JP5354277B2 - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power conversion device which can directly detect open failures of a switching element by specifying the element in a normal operation state. <P>SOLUTION: A motor control device includes a switching circuit constituted by directly connecting two IGBTs. Each IGBT comprises a current sense terminal; a control circuit acquires a current flowing to the IGBT from an output of the current sense terminal of the IGBT connected to a positive electrode terminal of a battery while controlling the switching circuit so that a current flows out, and also acquires a current flowing to the IGBT from that of the IGBT connected to a negative electrode terminal of the battery while controlling the switching circuit so that a current flows in; the control circuit determines that the IGBT has the open failure when the acquired current is smaller than a target current, and when a difference between both the currents is equal to or larger than a determination threshold; and as a result, the open failure of the IGBT can be directly detected by specifying the element in normal operating state. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to a power conversion device including a switching circuit composed of switching elements.

  2. Description of the Related Art Conventionally, there is an inverter device disclosed in Patent Document 1, for example, as a power conversion device including a switching circuit made of a switching element. The inverter device includes a main circuit reverse conversion unit, a current detector, and a control device. The main circuit inverse conversion unit is configured by connecting two sets of two switching elements connected in series in parallel. Based on the detection result of the current detector, the control device turns on and off the switching elements constituting the main circuit inverse conversion unit, converts the input DC power into AC power, and supplies the AC power to the AC motor. By the way, this inverter device is provided with an abnormality determination circuit in order to detect an abnormality of the switching element constituting the main circuit inverse conversion unit. When a signal is output from the abnormality determination circuit, the control device sequentially turns on and off the switching elements constituting the main circuit inverse conversion unit based on a predetermined conduction pattern for detecting abnormality set in advance. The abnormality determination circuit determines whether the switching element is abnormal based on the detection result of the current detector corresponding to the conduction pattern. Thereby, it is possible to detect an abnormality of the switching element by specifying the element.

JP-A-8-308244

  In the inverter device described above, when an abnormality of the switching element is detected, the switching element must be turned on / off based on a predetermined conduction pattern for detecting the abnormality. For this reason, there is a problem that an abnormality of the switching element cannot be detected in a normal operation state in which the input DC power is converted into AC power and output. On the other hand, it is conceivable to detect the abnormality of the switching element indirectly by detecting another abnormality that secondarily occurs with the abnormality of the switching element. However, in this case, there is a possibility that a part other than the switching element is secondarily damaged.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a power conversion device capable of directly detecting an open failure of a switching element by specifying the element in a normal operation state. To do.

 Therefore, as a result of intensive research and trial and error to solve this problem, the present inventor constituted a switching circuit with a switching element having a current sense terminal, and determined based on the output of the current sense terminal, The inventors have come up with the idea that an open failure of a switching element can be directly detected by specifying the element in a normal operating state, and the present invention has been completed.

  That is, the power conversion device according to claim 1 is configured by connecting two switching elements in series, the input terminals are formed at both ends of the switching elements connected in series, and the output terminals are formed at the series connection points, respectively. The switching element connected to the positive terminal of the power supply so that the alternating current of the target amplitude value is output from the switching circuit whose terminal is connected to the power supply and the control terminal of the switching element, respectively, and is output from the output terminal of the switching circuit And a control circuit that complementarily turns on and off the switching element connected to the negative electrode terminal of the power supply, the switching element is turned on according to the flowing current when the current flows A current sense terminal that outputs current, and the control circuit controls the switching circuit so that current flows out of the output terminal. During the period, based on the output of the current sense terminal of the switching element connected to the positive terminal of the power source and the target amplitude value, an open failure of the switching element connected to the positive terminal of the power source is detected, and the current is output to the output terminal. Switching element connected to the negative terminal of the power source based on the output of the current sense terminal of the switching element connected to the negative terminal of the power source and the target amplitude value during the period in which the switching circuit is controlled to flow It is characterized by detecting an open failure.

  According to this configuration, the control circuit complementarily turns on and off the two switching elements connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. During a period in which the control circuit controls the switching circuit so that a current flows out from the output terminal, a current having a target amplitude value flows through the switching element connected to the positive terminal of the power supply at any timing. . In contrast, during the period in which the control circuit controls the switching circuit so that current flows into the output terminal, the current of the target amplitude value is applied to the switching element connected to the negative terminal of the power supply at any timing. It will flow. However, if the switching element has an open failure, the current having the target amplitude value does not flow through the switching element even during the above-described period. Here, the current flowing through the switching element is obtained based on the output of the current sense terminal. Therefore, during the period when the switching circuit is controlled so that current flows out from the output terminal, based on the output of the current sense terminal of the switching element connected to the positive terminal of the power supply and the target amplitude value, During the period when the switching circuit is controlled so that the current flows into the output terminal, the switching element breaks down based on the output of the current sense terminal of the switching element connected to the negative terminal of the power source and the target amplitude value. It can be directly determined whether or not. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in a normal operation state, an open failure of the switching element can be directly detected by specifying the element.

  The power conversion device according to claim 2, wherein the control circuit is connected to the positive terminal of the power source obtained from the output of the current sense terminal during the period in which the switching circuit is controlled so that current flows out from the output terminal. When the current flowing through the switching element is smaller than the target amplitude value and the difference between the currents is equal to or greater than the determination threshold, it is determined that the switching element connected to the positive terminal of the power supply has an open failure, and the output terminal During the period in which the switching circuit is controlled so that current flows, the current flowing through the switching element connected to the negative terminal of the power source obtained from the output of the current sense terminal is smaller than the target amplitude value, and When the difference is greater than or equal to the determination threshold, it is determined that the switching element connected to the negative terminal of the power supply has an open failure. According to this configuration, an open failure of the switching element can be reliably detected.

  The power conversion device according to claim 3 is configured by connecting two sets of switching element groups each having a plurality of switching elements in parallel, and input terminals are connected to both ends of the series-connected switching element groups. The output terminal is formed on the power supply circuit, the input terminal is connected to the power supply, and the control terminal of the switching element is connected to the power supply so that the alternating current of the target amplitude value is output from the output terminal of the switching circuit. A power conversion device comprising: a switching element constituting a switching element group connected to a positive terminal of the power supply; and a control circuit that complementarily turns on and off the switching element constituting the switching element group connected to a negative terminal of a power source In the current sense, when the switching element is turned on and a current flows, the current sensing outputs a current corresponding to the flowing current. In the period when the control circuit controls the switching circuit so that current flows out from the output terminal, the output of the current sense terminal of the switching element that constitutes the switching element group connected to the positive terminal of the power supply Based on the target amplitude value and the target amplitude value, the switching circuit constituting the switching element group connected to the positive electrode terminal of the power source is detected and the switching circuit is controlled so that the current flows into the output terminal. Based on the output of the current sense terminal of the switching element that constitutes the switching element group connected to the negative terminal of the power source and the target amplitude value, the switching element that constitutes the switching element group connected to the negative terminal of the power source is opened. It is characterized by detecting a failure.

  According to this configuration, the control circuit complementarily turns on the switching elements constituting the two sets of switching elements connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. Turn off. During the period in which the control circuit controls the switching circuit so that current flows out from the output terminal, the target amplitude value is set to the switching element constituting the switching element group connected to the positive terminal of the power supply at any timing. A current having a target amplitude value per element flows divided by the number of switching elements connected in parallel. In contrast, during the period in which the control circuit controls the switching circuit so that current flows into the output terminal, the target amplitude per element at any timing is applied to the switching element connected to the negative terminal of the power supply. Value current will flow. However, when an open failure occurs in a switching element, a current having a target amplitude value per element does not flow through the switching element even during the above-described period. Here, the current flowing through the switching element is obtained based on the output of the current sense terminal. Therefore, during the period in which the switching circuit is controlled so that current flows out from the output terminal, it is based on the output of the current sense terminal of the switching element connected to the positive electrode terminal of the power supply and the target amplitude value. On the other hand, during the period when the switching circuit is controlled so that current flows into the output terminal, the output of the current sense terminal of the switching element connected to the negative terminal of the power supply and the target amplitude Based on the value, it can be directly determined whether or not the switching element has failed. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in a normal operation state, an open failure of the switching element can be directly detected by specifying the element.

  The power conversion device according to claim 4, wherein the control circuit is connected to the positive terminal of the power source obtained from the output of the current sense terminal during the period in which the switching circuit is controlled so that current flows out from the output terminal. The current flowing through the switching elements constituting the switching element group is smaller than the target amplitude value per element obtained by dividing the target amplitude value by the number of switching elements connected in parallel, and the difference between these currents is equal to or greater than the determination threshold value. When the switching circuit constituting the switching element group connected to the positive electrode terminal of the power source is determined to be open failure and the switching circuit is controlled so that current flows into the output terminal, the current sensing terminal The current flowing through the switching elements that constitute the switching element group connected to the negative terminal of the power source, obtained from the output, is the target amplitude value. Switching that constitutes a group of switching elements connected to the negative terminal of the power supply when the amplitude is smaller than the target amplitude value per element divided by the number of switching elements connected in parallel and the current difference is equal to or greater than the determination threshold It is determined that the element has an open failure. According to this configuration, an open failure of the switching element can be reliably detected.

  The power conversion device according to claim 5 is configured by serially connecting two sets of switching element groups each having a plurality of switching elements arranged in parallel, and input terminals are connected to both ends of the series-connected switching element groups. A switching circuit in which an output terminal is formed and an input terminal is connected to a power source, a current sensor that detects a current output from the output terminal of the switching circuit, a control terminal of the switching element, and an output terminal of the current sensor, respectively Based on the detection result of the current sensor, the switching elements constituting the switching element group connected to the positive terminal of the power source and the power source so that the alternating current of the target amplitude value is output from the output terminal of the switching circuit. A control circuit for complementarily turning on and off the switching elements constituting the switching element group connected to the negative electrode terminal; When the switching element is turned on and a current flows, the switching element has a current sense terminal that outputs a current corresponding to the flowing current, and the control circuit is configured so that the current flows out from the output terminal. During the period in which the switching circuit is controlled, the positive electrode of the power source is determined based on the output of the current sense terminal of the switching element constituting the switching element group connected to the positive electrode terminal of the power source and the output current detected by the current sensor. The switching element group connected to the negative terminal of the power source during the period when the open circuit of the switching element constituting the switching element group connected to the terminal is detected and the switching circuit is controlled so that current flows into the output terminal The negative terminal of the power source based on the output of the current sense terminal of the switching element and the output current detected by the current sensor And detecting an open fault in switching elements constituting the switching elements connected groups.

  According to this configuration, the control circuit complementarily turns on the switching elements constituting the two sets of switching elements connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. Turn off. The current output from the output terminal of the switching circuit is detected by a current sensor. During the period in which the control circuit controls the switching circuit so that current flows out from the output terminal, the amplitude of the output current is applied to the switching element constituting the switching element group connected to the positive terminal of the power supply at any timing. That is, a current having an output amplitude value per element flows by dividing the output amplitude value by the number of switching elements connected in parallel. On the other hand, during the period in which the control circuit controls the switching circuit so that current flows into the output terminal, the output amplitude per element is applied to the switching element connected to the negative terminal of the power supply at any timing. Value current will flow. However, if an open failure occurs in a switching element, a current having an output amplitude value per element does not flow through the switching element even during the above-described period. Here, the current flowing through the switching element is obtained based on the output of the current sense terminal. Therefore, during the period when the switching circuit is controlled so that current flows out from the output terminal, the output of the current sense terminal of the switching element constituting the switching element group connected to the positive terminal of the power supply and the output detected by the current sensor On the other hand, during the period in which the switching circuit is controlled so that the current flows into the output terminal, the current sensing terminal of the switching element constituting the switching element group connected to the negative terminal of the power supply Based on the output and the output current detected by the current sensor, it can be directly determined whether or not the switching element has failed. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in a normal operation state, an open failure of the switching element can be directly detected by specifying the element.

  The power conversion device according to claim 6, wherein the control circuit is connected to the positive terminal of the power source obtained from the output of the current sense terminal during the period in which the switching circuit is controlled so that current flows out from the output terminal. The current flowing through the switching elements constituting the switching element group is smaller than the output amplitude value per element obtained by dividing the output amplitude value obtained from the output current detected by the current sensor by the number of parallel connections of the switching elements, and When the difference between the currents is equal to or greater than the determination threshold, it is determined that the switching elements constituting the switching element group connected to the positive electrode terminal of the power supply have an open failure, and the switching circuit is set so that the current flows into the output terminal. During the period of control, the switching elements constituting the switching element group connected to the negative terminal of the power source obtained from the output of the current sense terminal are used. The current flowing through the chucking element is smaller than the output amplitude value per element obtained by dividing the output amplitude value obtained from the output current detected by the current sensor by the number of parallel connections of the switching elements, and the difference between these currents is When it is equal to or higher than the determination threshold, it is determined that an open failure has occurred in a switching element that constitutes a switching element group connected to the negative terminal of the power supply. According to this configuration, an open failure of the switching element can be reliably detected.

  The power conversion device according to claim 7 is configured by serially connecting two sets of switching element groups in which a plurality of switching elements are arranged in parallel, and input terminals are connected to both ends of the series-connected switching element groups. A switching circuit in which an output terminal is formed and an input terminal is connected to a power source, a current sensor that detects a current output from the output terminal of the switching circuit, a control terminal of the switching element, and an output terminal of the current sensor, respectively Based on the detection result of the current sensor, the switching elements constituting the switching element group connected to the positive terminal of the power source and the power source so that the alternating current of the target amplitude value is output from the output terminal of the switching circuit. A control circuit for complementarily turning on and off the switching elements constituting the switching element group connected to the negative electrode terminal; When the switching element is turned on and a current flows, the switching element has a current sense terminal that outputs a current corresponding to the flowing current, and the control circuit is configured so that the current flows out from the output terminal. During the period in which the switching circuit is controlled, the switching element group connected to the positive terminal of the power source is selected based on the output of the current sense terminal of the switching element constituting the switching element group connected to the positive terminal of the power source. In the period when the switching circuit is controlled so that an open failure of the switching element is detected and the current flows into the output terminal, the current sense terminal of the switching element constituting the switching element group connected to the negative terminal of the power supply Based on the output of the switching element, the switching element constituting the switching element group connected to the negative terminal of the power source And detecting the emissions failure.

  According to this configuration, the control circuit complementarily turns on the switching elements constituting the two sets of switching elements connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. Turn off. During a period in which the control circuit controls the switching circuit so that current flows out from the output terminal, an equal current flows through each of the switching elements constituting the switching element group connected to the positive terminal of the power supply. On the other hand, during the period when the control circuit controls the switching circuit so that current flows into the output terminal, equal current flows through each of the switching elements constituting the switching element group connected to the negative terminal of the power supply. It becomes. However, if one of the switching elements constituting the switching element group has an open failure, no current flows through the switching element, but a larger current flows through the other switching elements. That is, the current flowing through the switching element is different between a normal time and an open failure. Here, the current flowing through the switching element can be obtained based on the output of the current sense terminal. Therefore, during the period when the switching circuit is controlled so that current flows out from the output terminal, based on the output of the current sense terminal of the switching element constituting the switching element group connected to the positive electrode terminal of the power supply, During the period when the switching circuit is controlled so that current flows into the output terminal, the switching element is opened based on the output of the current sense terminal of the switching element constituting the switching element group connected to the negative terminal of the power source. It is possible to directly determine whether or not a failure has occurred. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in a normal operation state, an open failure of the switching element can be directly detected by specifying the element.

  The power converter according to claim 8 is connected to the positive terminal of the power source obtained from the output of the current sense terminal during the period in which the control circuit controls the switching circuit so that the current flows out from the output terminal. The current flowing in one switching element that constitutes the switching element group is smaller than the current flowing in all other switching elements, and the current flowing in one switching element and the current flowing in all other switching elements. When all the differences are equal to or greater than the determination threshold, it is determined that one switching element constituting the switching element group connected to the positive electrode terminal of the power supply has an open failure, and the switching circuit is set so that current flows into the output terminal. During the controlled period, the switching element connected to the negative terminal of the power source, obtained from the output of the current sense terminal, is used. The current flowing through one switching element constituting the group is smaller than the current flowing through all other switching elements, and the difference between the current flowing through one switching element and the current flowing through all other switching elements is When all are equal to or greater than the determination threshold, it is determined that one switching element constituting the switching element group connected to the negative terminal of the power supply has an open failure. According to this configuration, an open failure of the switching element can be reliably detected.

  In the power conversion device according to claim 9, the control circuit is based on a command input from the external device and a physical quantity indicating a state of the load device input from the load device connected to the output terminal of the switching circuit. A target amplitude value is determined, and an open failure of a switching element is detected based on at least one of a command input from an external device and a physical quantity indicating a state of a load device. According to this configuration, an open failure of the switching element can be detected based on a command input from the outside or a physical quantity indicating a load state.

  The power conversion device according to claim 10 is characterized in that the control circuit does not determine the open failure of the switching element when the target amplitude value is a predetermined value or less. According to this configuration, erroneous determination of an open failure can be prevented.

  The power conversion device according to claim 11 is characterized in that the determination threshold is set so as not to be affected by an output error of the current sensor. According to this configuration, it is possible to prevent erroneous determination associated with the output error of the current sensor.

  The power conversion device according to claim 12 is characterized in that the determination threshold is set so as not to be affected by an output error of the current sense terminal. According to this configuration, it is possible to prevent erroneous determination associated with the output error of the current sense terminal.

  A power conversion device according to a thirteenth aspect is mounted on a vehicle and converts DC power into AC power. According to this configuration, in a power conversion device that is mounted on a vehicle and converts DC power to AC power, an open failure of a switching element can be identified and directly detected in a normal operating state.

  According to a fourteenth aspect of the present invention, there is provided a power converter that supplies AC power to an AC motor mounted on a vehicle. According to this configuration, in a power converter that supplies AC power to an AC motor mounted on a vehicle, an open failure of the switching element can be directly detected by specifying the element in a normal operation state.

It is a circuit diagram of the motor control device in a 1st embodiment. 3 is a flowchart for explaining an open failure detection operation of an IGBT in the motor control device of FIG. 1. It is a circuit diagram of the motor control apparatus in 2nd Embodiment. 4 is a flowchart for explaining an open failure detection operation of an IGBT in the motor control device of FIG. 3. It is a flowchart for demonstrating the open failure detection operation | movement of IGBT in the motor control apparatus of 3rd Embodiment. It is a flowchart for demonstrating the open failure detection operation | movement of IGBT in the motor control apparatus of 4th Embodiment.

  Next, the present invention will be described in more detail with reference to embodiments. In this embodiment, an example in which the power conversion device according to the present invention is applied to a motor control device that is mounted on a vehicle, converts DC power to AC power, and supplies the same to a three-phase AC motor mounted on the vehicle. Show.

(First embodiment)
First, the configuration of the motor control device will be described with reference to FIG. Here, FIG. 1 is a circuit diagram of the motor control device according to the first embodiment.

  A motor control device 1 (power conversion device) shown in FIG. 1 converts a DC voltage output from a battery B1 (power supply) into a three-phase AC voltage and supplies the same to a three-phase AC motor M1 (load device). It is a device for driving the motor M1. That is, it is a device that converts DC power into AC power and drives the three-phase AC motor M1. The motor control device 1 includes a smoothing capacitor 10, a power conversion circuit 11, a drive circuit 12, current sensors 13 and 14, and a control circuit 15.

  The smoothing capacitor 10 is an element for smoothing the DC voltage of the battery B1. The positive terminal and the negative terminal of the smoothing capacitor 10 are connected to the positive terminal and the negative terminal of the battery B1, respectively.

  The power conversion circuit 11 is a circuit that converts the DC voltage of the battery B1 smoothed by the smoothing capacitor 10 into a three-phase AC voltage and supplies it to the three-phase AC motor M1. That is, it is a circuit that converts DC power into AC power and supplies it to the three-phase AC motor M1. The power conversion circuit 11 includes switching circuits 110 to 112.

  The switching circuit 110 is composed of two IGBTs 110a and 110b (switching elements). The IGBTs 110a and 110b include a current sense terminal S that outputs a current smaller than the flowing current that is proportional to the flowing current when the current flows when the IGBT is turned on. The IGBTs 110a and 110b are connected in series. Specifically, the emitter terminal E of the IGBT 110a is connected to the collector terminal C of the IGBT 110b. Input terminals are formed at both ends of the IGBTs 110a and 110b connected in series, and output terminals are formed at the series connection points. The collector terminal C of the IGBT 110a which is one input terminal is connected to the positive terminal of the battery B1. The emitter terminal E of the IGBT 110b, which is the other input terminal, is connected to the negative terminal of the battery B1. The output terminal is connected to the U-phase terminal of the three-phase AC motor M1. The gate terminals G (control terminals) of the IGBTs 110a and 110b are connected to the drive circuit 12, respectively. Further, the current sense terminals S are connected to the control circuit 15 respectively.

  The switching circuit 111 includes IGBTs 110a and 110b. The switching circuit 112 includes IGBTs 112a and 112b. The switching circuits 111 and 112 have the same configuration as the switching circuit 110.

  The drive circuit 12 is a circuit that outputs a drive signal based on the drive command signal input from the control circuit 15 and drives the IGBTs 110a, 110b, 111a, 111b, 112a, and 112b. The drive circuit 12 is connected to the control circuit 15. Further, the gate terminals G of the IGBTs 110a, 110b, 111a, 111b, 112a, and 112b are respectively connected.

The current sensors 13 and 14 are elements that respectively detect a U-phase current and a W-phase current supplied from the power conversion circuit 11 to the three-phase AC motor M1. Current sensors 13 and 14 output signals corresponding to the U-phase current and the W-phase current, respectively. Current sensor 13 is provided between the output terminal of switching circuit 110 and the U-phase terminal of three-phase AC motor M1. The current sensor 14 is provided between the output terminal of the switching circuit 112 and the W-phase terminal of the three-phase AC motor M1.

  The control circuit 15 detects the command signal input from the controller C1 (external device), the rotation angle of the three-phase AC motor M1 detected by the rotation angle sensor R1 (physical quantity indicating the state of the load device), and the current sensors 13 and 14. The switching circuits 110 to 112 are controlled based on the U-phase current and the W-phase current of the three-phase AC motor M1. Further, it is also a circuit that detects an open failure of the IGBTs 110a, 110b, 111a, 111b, 112a, and 112b constituting the switching circuits 110 to 112 based on the output of the current sense terminal S and the target amplitude value. Here, the target amplitude value indicates the amplitude of the alternating current to be output from the switching circuits 110 to 112. During the period in which the control circuit 15 controls the switching circuits 110 to 112 so that current flows from the output terminal, the target amplitude is applied to the IGBTs 110a, 111a, and 112a connected to the positive terminal of the battery B1 at any timing. Value current will flow. On the other hand, during the period in which the control circuit 15 controls the switching circuits 110 to 112 so that current flows into the output terminal, any one of the IGBTs 110b, 111b, and 112b connected to the negative terminal of the battery B1 The current of the target amplitude value flows at the timing. The target amplitude value is determined based on the command signal, the rotation angle, the U-phase current, and the W-phase current.

  The control circuit 15 is based on the command signal input from the controller C1, the rotation angle that is the detection result of the rotation angle sensor R1, the U-phase current and the W-phase current that are the detection results of the current sensors 13 and 14, and the switching circuit 110. Determine the target amplitude value for ~ 112. And the drive command signal for turning on / off IGBT110a, 110b, 111a, 111b, 112a, 112b is output so that the alternating current of a target amplitude value may be output from the output terminal of switching circuits 110-112. Specifically, drive command signals for turning on and off the IGBTs 110a and 110b, the IGBTs 111a and 111b, and the IGBTs 112a and 112b in a complementary manner are output. Further, during the period in which the switching circuits 110 to 112 are controlled so that current flows out from the output terminals, these IGBTs are opened based on the outputs of the current sense terminals S and the target amplitude values of the IGBTs 110a, 111a, and 112a. Detect failure. On the other hand, during the period in which the switching circuits 110 to 112 are controlled so that current flows into the output terminals, these IGBTs are based on the outputs of the current sense terminals S and the target amplitude values of the IGBTs 110b, 111b, and 112b. Detects open failure.

  The control circuit 15 is connected to the controller C1. Moreover, it connects to the rotation angle sensor R1 and the current sensors 13 and 14, respectively. Further, they are connected to the current sense terminals S of the IGBTs 110a, 110b, 111a, 111b, 112a, 112b, respectively.

  Next, the operation of the motor control device will be described with reference to FIG. In FIG. 1, the control circuit 15 includes a command signal input from the controller C1, a rotation angle of the three-phase AC motor M1 detected by the rotation angle sensor R1, and a U phase of the three-phase AC motor M1 detected by the current sensors 13 and 14. Based on the current and the W-phase current, target amplitude values to be output by the switching circuits 110 to 112 are determined. And the drive command signal for turning on / off IGBT110a, 110b, 111a, 111b, 112a, 112b is output so that the alternating current of a target amplitude value may be output from the output terminal of switching circuits 110-112. Specifically, drive command signals for turning on and off the IGBTs 110a and 110b, the IGBTs 111a and 111b, and the IGBTs 112a and 112b in a complementary manner are output. The drive circuit 12 outputs a drive signal based on the drive command signal input from the control circuit 15, and drives IGBT110a, 110b, 111a, 111b, 112a, 112b. Thereby, the IGBTs 110a, 110b, 111a, 111b, 112a, 112b are turned on and off, and the DC voltage of the battery B1 smoothed by the smoothing capacitor 10 is converted into a three-phase AC voltage and supplied to the three-phase AC motor M1. . That is, DC power is converted into AC power and supplied to the three-phase AC motor M1.

  Next, the open failure detection operation of the IGBT will be described in detail with reference to FIGS. Here, FIG. 2 is a flowchart for explaining an open failure detection operation of the IGBT in the motor control device of FIG.

  As shown in FIG. 2, the control circuit 15 shown in FIG. 1 determines whether or not it is a period during which the switching circuit is controlled so that current flows out from the output terminal (step S100). In step S100, when it is the period, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT connected to the positive terminal of the battery B1 (step S101). Thereafter, the control circuit 15 determines whether or not the current flowing through the IGBT is smaller than the target amplitude value and the difference between the currents is greater than or equal to the determination threshold value during the period (step S102). Here, the determination threshold is a threshold for determining whether or not the current flowing through the IGBT obtained from the output of the current sense terminal S is the target amplitude value based on the difference between the currents. The determination threshold value is set to a value that is not affected by the output error of the current sense terminal S so as not to be erroneously determined due to the effect of the output error of the current sense terminal S.

  In step S102, when the current flowing through the IGBT during the period is smaller than the target amplitude value and the difference between the currents is equal to or greater than the determination threshold value, it is considered that the current of the target amplitude value does not flow. Then, it is determined that the IGBT has an open failure (step S103). On the other hand, in step S102, when the current flowing through the IGBT during the period is smaller than the target amplitude value and the difference between the currents is not equal to or greater than the determination threshold, the target amplitude is detected at any timing during the period. Since it is considered that the current of the value has flowed, it is determined that the IGBT does not have an open failure (step S104).

  On the other hand, in step S100, when it is not a period in which the switching circuit is controlled so that current flows out from the output terminal, the control circuit 15 is in a period in which the switching circuit is controlled so that current flows into the output terminal. Is determined (step S105). In step S105, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT connected to the negative terminal of the battery B1 during the period (step S106). Thereafter, the control circuit 15 determines whether or not the current flowing through the IGBT is smaller than the target amplitude value and the difference between the currents is greater than or equal to the determination threshold value during the period (step S107). Here, the determination threshold is the same as the determination threshold in step S102.

  In step S107, when the current flowing through the IGBT is smaller than the target amplitude value during the period and the difference between the currents is equal to or greater than the determination threshold value, it is considered that the current of the target amplitude value does not flow. It is determined that the IGBT has an open failure (step S103). On the other hand, in step S107, when the current flowing through the IGBT is smaller than the target amplitude value during the period and the difference between the currents is not equal to or greater than the determination threshold, at any timing during the period, the target amplitude Since it is considered that the current of the value is flowing, it is determined that the IGBT does not have an open failure (step S104).

  In step S105, when it is not a period in which the switching circuit is controlled so that current flows into the output terminal, the process returns to step S100.

  For example, during the period in which the control circuit 15 controls the switching circuit 110 so that current flows out from the output terminal, the current flowing from the output of the current sense terminal S of the IGBT 110a connected to the positive terminal of the battery B1 to the IGBT 110a. Ask. Thereafter, during the period, it is determined whether or not the current flowing through the IGBT 110a is smaller than the target amplitude value and the difference between the currents is equal to or greater than a determination threshold value. Then, during the period, when the current flowing through the IGBT 110a is smaller than the target amplitude value and the difference between the currents is equal to or larger than the determination threshold value, the IGBT 110a is determined to be open, and otherwise, the IGBT 110a is Judge that there is no open failure.

  On the other hand, during the period in which the control circuit 15 controls the switching circuit 110 so that current flows into the output terminal, the current flowing from the output of the current sense terminal S of the IGBT 110b connected to the negative terminal of the battery B1 to the IGBT 110b. Ask. Thereafter, during the period, it is determined whether the current flowing through the IGBT 110b is smaller than the target amplitude value and the difference between the currents is equal to or greater than a determination threshold value. Then, during the period, when the current flowing through the IGBT 110b is smaller than the target amplitude value and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 110b has an open failure, and otherwise, the IGBT 110b Judge that there is no open failure.

  The control circuit 15 shown in FIG. 1 repeats the same processing, and determines whether or not there is an open failure for all IGBTs in a normal operation state.

  Finally, the effect will be described. According to the first embodiment, the control circuit 15 complementarily turns on and off the two IGBTs connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. During the period in which the control circuit 15 controls the switching circuit so that current flows out from the output terminal, the current of the target amplitude value flows through the IGBT connected to the positive terminal of the battery B1 at any timing. Become. On the other hand, during the period when the control circuit 15 controls the switching circuit so that the current flows into the output terminal, the current connected to the negative terminal of the battery B1 has the current of the target amplitude value at any timing. Will flow. However, if the IGBT has an open failure, the current having the target amplitude value does not flow through the IGBT even during the above-described period. Here, the current flowing through the IGBT is obtained based on the output of the current sense terminal S. Therefore, during the period in which the switching circuit is controlled so that current flows out from the output terminal, based on the output of the current sense terminal S of the IGBT connected to the positive terminal of the battery B1 and the target amplitude value, During the period in which the switching circuit is controlled so that current flows into the output terminal, the IGBT fails based on the output of the current sense terminal S of the IGBT connected to the negative terminal of the battery B1 and the target amplitude value. It can be directly determined whether or not. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in the motor control device 1 that is mounted on a vehicle and converts DC power into AC power to the three-phase AC motor M1 mounted on the vehicle, an open failure of the IGBT is directly identified and specified in the normal operation state. Can be detected.

  Further, according to the first embodiment, during the period when the control circuit 15 controls the switching circuit so that current flows out from the output terminal, the current flowing through the IGBT connected to the positive terminal of the battery B1 is the target amplitude value. When it is smaller and the difference between the currents is equal to or greater than the determination threshold, it is determined that the IGBT has an open failure, and the battery B1 is controlled during the period when the switching circuit is controlled so that the current flows into the output terminal. When the current flowing through the IGBT connected to the negative electrode terminal of the current is smaller than the target amplitude value and the difference between the currents is equal to or larger than the determination threshold value, it is determined that the IGBT has an open failure. Therefore, an open failure of the IGBT can be reliably detected.

  Further, according to the first embodiment, the determination threshold value is set to a value that is not affected by the output error of the current sense terminal so that the determination threshold value is not erroneously determined due to the effect of the output error of the current sense terminal S. Yes. For this reason, it is possible to prevent erroneous determination due to an output error of the current sense terminal.

(Second Embodiment)
Next, the motor control device of the second embodiment will be described. The motor control device according to the second embodiment is an IGBT formed by connecting two IGBTs in parallel, whereas the motor control device according to the first embodiment configures a switching circuit by connecting two IGBTs in series. Two groups are connected in series to form a switching circuit.

  First, the configuration of the motor control device will be described with reference to FIG. Here, FIG. 3 is a circuit diagram of the motor control device according to the second embodiment. Here, only the configuration of the switching circuit, which is different from the motor control device of the first embodiment, will be described, and description of common parts will be omitted.

As shown in FIG. 3, the motor controller 2, a smoothing capacitor 20, a power conversion circuit 21, a drive circuit 22, and a current sensor 23, and a control circuit 25.

  The power conversion circuit 21 includes switching circuits 210 to 212. The switching circuit 210 includes two sets of IGBT groups 2100 and 2101 (switching element groups). The IGBT group 2100 is composed of two IGBTs 2100a and 2100b connected in parallel. The IGBT group 2101 is configured by two IGBTs 2101a and 2101b connected in parallel. The IGBTs 2100a, 2100b, 2101a, and 2101b each include a current sense terminal S that outputs a current that is proportional to the flowing current and smaller than the flowing current when the current flows. The IGBT groups 2100 and 2101 are connected in series. Specifically, the emitter terminals E of the IGBTs 2100a and 2100b are connected to the collector terminals C of the IGBTs 2101a and 2101b. Input terminals are formed at both ends of the IGBT groups 2100 and 2101 connected in series, and output terminals are formed at the series connection points. The collector terminals C of the IGBTs 2100a and 2100b, which are one input terminal, are connected to the positive terminal of the battery B2. The emitter terminal E of IGBTs 2101a and 2101b, which are the other input terminals, is connected to the negative terminal of the battery B2. The output terminal is connected to the U-phase terminal of the three-phase AC motor M2. The gate terminals G of the IGBTs 2100a, 2100b, 2101a, and 2101b are connected to the drive circuit 22, respectively. Further, the current sense terminals S are connected to the control circuit 15 respectively.

  The switching circuit 211 includes an IGBT group 2110 composed of IGBTs 2110a and 2110b, and an IGBT group 2111 composed of IGBTs 2111a and 2111b. The switching circuit 212 includes an IGBT group 2120 composed of IGBTs 2120a and 2120b, and an IGBT group 2121 composed of IGBTs 2121a and 2121b. The switching circuits 211 and 212 have the same configuration as the switching circuit 210.

  Next, the operation of the motor control device will be described with reference to FIGS. The operation of the motor control device of the second embodiment is the same as the operation of the motor control device of the first embodiment except for the open failure detection operation of the IGBT. Therefore, the IGBT open failure detection operation in the motor control device will be described. Here, FIG. 4 is a flowchart for explaining an open failure detection operation of the IGBT in the motor control device of FIG.

  As shown in FIG. 4, the control circuit 25 shown in FIG. 3 determines whether or not it is a period during which the switching circuit is controlled so that a current flows out from the output terminal (step S200). In step S200, when it is the said period, the electric current which flows into the said IGBT is calculated | required from the output of the current sense terminal S of IGBT which comprises the IGBT group connected to the positive electrode terminal of battery B2 (step S201). Thereafter, the control circuit 25 determines that the current flowing in the IGBT during the period is smaller than the target amplitude value per element of the IGBT obtained by dividing the target amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group, and Then, it is determined whether or not the difference between these currents is equal to or greater than a determination threshold (step S202). Here, the determination threshold is used to determine whether or not the current flowing through the IGBT obtained from the output of the current sense terminal S is a target amplitude value per one element of the IGBT based on the difference between the currents. It is a threshold value. The determination threshold value is set to a value that is not affected by the output error of the current sense terminal S so as not to be erroneously determined due to the effect of the output error of the current sense terminal S.

  In step S202, when the current flowing through the IGBT during the period is smaller than the target amplitude value per IGBT element and the difference between the currents is equal to or greater than the determination threshold, the target amplitude per IGBT element Since it is considered that the current of the value does not flow, it is determined that the IGBT has an open failure (step S203). On the other hand, in step S202, when the current flowing through the IGBT during the period is smaller than the target amplitude value per IGBT element and the difference between the currents is not equal to or greater than the determination threshold value, Since it is considered that the current of the target amplitude value per one element of the IGBT has flowed at this timing, it is determined that the IGBT does not have an open failure (step S204).

  On the other hand, in step S200, when it is not a period in which the switching circuit is controlled so that current flows out from the output terminal, the control circuit 25 is in a period in which the switching circuit is controlled so that current flows into the output terminal. Is determined (step S205). In step S205, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the negative terminal of the battery B2 during the period (step S206). Thereafter, the control circuit 25 is configured such that during the period, the current flowing through the IGBT is smaller than the target amplitude value per element of the IGBT obtained by dividing the target amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group, and It is determined whether or not the difference between these currents is greater than or equal to a determination threshold (step S207). Here, the determination threshold value is the same as the determination threshold value in step S202.

  In step S207, when the current flowing through the IGBT during the period is smaller than the target amplitude value per IGBT element and the difference between the currents is equal to or greater than the determination threshold, the current of the target amplitude value is flowing. Therefore, it is determined that the IGBT has an open failure (step S203). On the other hand, in step S207, if the current flowing through the IGBT during the period is smaller than the target amplitude value per IGBT element and the difference between the currents is not equal to or greater than the determination threshold value, Since it is considered that the current of the target amplitude value per one element of the IGBT is flowing at this timing, it is determined that the IGBT is not in an open failure (step S204).

  In step S205, when it is not a period in which the switching circuit is controlled so that current flows into the output terminal, the process returns to step S200.

  For example, during the period in which the control circuit 25 controls the switching circuit 210 so that current flows out from the output terminal, the output of the current sense terminal S of the IGBT 2100a constituting the IGBT group 2100 connected to the positive terminal of the battery B2 To obtain the current flowing through the IGBT 2100a. Thereafter, during this period, it is determined whether or not the current flowing through the IGBT 2100a is smaller than the target amplitude value per IGBT element, and the difference between the currents is equal to or greater than a determination threshold value. Here, the target amplitude value per element of the IGBT is a value obtained by dividing the target amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group 2100. When the current flowing through the IGBT 2100a is smaller than the target amplitude value per IGBT element during the period and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 2100a has an open failure. Otherwise, the IGBT 2100a determines that there is no open failure.

  On the other hand, during the period when the control circuit 25 controls the switching circuit 210 so that the current flows into the output terminal, the output of the current sense terminal S of the IGBT 2101a constituting the IGBT group 2101 connected to the negative terminal of the battery B2. To obtain the current flowing through the IGBT 2101a. Thereafter, during this period, it is determined whether or not the current flowing through the IGBT 2101a is smaller than the target amplitude value per IGBT element and the difference between the currents is equal to or greater than a determination threshold value. Here, the target amplitude value per element of the IGBT is a value obtained by dividing the target amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group 2101. When the current flowing through the IGBT 2101a is smaller than the target amplitude value per IGBT element during the period and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 2101a has an open failure. Otherwise, it is determined that the IGBT 2101a does not have an open failure.

  The control circuit 25 shown in FIG. 3 repeats the same processing and determines whether or not there is an open failure for all IGBTs in a normal operation state.

  Finally, the effect will be described. According to the second embodiment, the control circuit 25 complementarily turns on the IGBTs constituting two sets of IGBT groups connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. Turn off. During a period in which the control circuit 25 controls the switching circuit so that current flows out from the output terminal, the target amplitude value is applied to the IGBT constituting the IGBT group connected to the positive terminal of the battery B2 at any timing. Is divided by the number of IGBTs connected in parallel, and a current having a target amplitude value per IGBT element flows. On the other hand, during the period in which the control circuit 25 controls the switching circuit so that current flows into the output terminal, the IGBT that constitutes the IGBT group connected to the negative terminal of the battery B2 has any timing. A current having a target amplitude value per IGBT element flows. However, if the IGBT has an open failure, the current having the target amplitude value per IGBT element does not flow through the IGBT even during the above-described period. Here, the current flowing through the IGBT is obtained based on the output of the current sense terminal S. Therefore, during the period in which the switching circuit is controlled so that current flows out from the output terminal, it is based on the output of the current sense terminal S of the IGBT and the target amplitude value that constitute the IGBT group connected to the positive terminal of the battery B2. On the other hand, during the period in which the switching circuit is controlled so that current flows into the output terminal, the output of the current sense terminal S of the IGBT and the target amplitude constituting the IGBT group connected to the negative terminal of the battery B2 Based on the value, it can be directly determined whether or not the IGBT has failed. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in the motor control device 2 that is mounted on the vehicle and converts the DC power into the AC power to the three-phase AC motor M2 mounted on the vehicle, the open failure of the IGBT is directly identified and specified in the normal operation state. Can be detected.

  In addition, according to the second embodiment, the control circuit 25 flows to the IGBTs constituting the IGBT group connected to the positive terminal of the battery B2 during the period in which the switching circuit is controlled so that current flows out from the output terminal. When the current is smaller than the target amplitude value per element of the IGBT and the difference between the currents is equal to or greater than the determination threshold, it is determined that the IGBT has an open failure, and the current flows into the output terminal. During the period when the switching circuit is controlled, the current flowing through the IGBTs constituting the IGBT group connected to the negative terminal of the battery B2 is smaller than the target amplitude value per IGBT element, and the difference between these currents is When it is equal to or greater than the determination threshold, it is determined that the IGBT has an open failure. Therefore, an open failure of the IGBT can be reliably detected.

(Third embodiment)
Next, the motor control apparatus of 3rd Embodiment is demonstrated. The motor control device of the third embodiment is different from the motor control device of the second embodiment that detects an open failure based on the output of the current sense terminal and the target current, whereas the output of the current sense terminal An open failure is detected based on the output current detected by the current sensor.

  Here, since the configuration of the motor control device of the third embodiment is the same as the configuration of the motor control device of the second embodiment, the description thereof is omitted.

  First, the operation of the motor control device will be described with reference to FIGS. The operation of the motor control device of the third embodiment is the same as the operation of the motor control device of the second embodiment except for the open failure detection operation of the IGBT. Therefore, an open failure detection operation of the IGBT will be described. Here, FIG. 5 is a flowchart for explaining an open failure detection operation of the IGBT in the motor control device of the third embodiment.

  As shown in FIG. 5, the control circuit 25 shown in FIG. 3 determines whether or not it is a period during which the switching circuit is controlled so that current flows out from the output terminal (step S300). In step S300, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the positive terminal of the battery B2 during the period (step S301). Thereafter, the output amplitude value of the switching circuit including the IGBT is obtained from the output current detected by the current sensor (step S302). Note that a current sensor that directly detects the output current of the switching circuit 211 is not provided, but can be obtained from the other current sensors 23 and 24. In the control circuit 25, the current flowing through the IGBT during the period is smaller than the output amplitude value per element of the IGBT obtained by dividing the output amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group, and Then, it is determined whether or not the difference between the currents is equal to or greater than a determination threshold (step S303). Here, the determination threshold is a threshold for determining whether or not the current flowing through the IGBT obtained from the output of the current sense terminal S is an output current per one element of the IGBT based on the difference between the currents. It is. The determination threshold value is set to a value that is not affected by the output error of the current sense terminal S and the current sensors 23 and 24 so as not to be erroneously determined due to the influence of the output error of the current sense terminal S and the current sensors 23 and 24 Is set.

In step S303, when the current flowing through the IGBT during the period is smaller than the output amplitude value per IGBT element and the difference between the currents is equal to or greater than the determination threshold, the output amplitude per IGBT element. Value current is considered not flowing,
It is determined that the IGBT has an open failure (step S304). On the other hand, in step S303, when the current flowing through the IGBT during the period is smaller than the output amplitude value per IGBT element and the difference between the currents is not equal to or greater than the determination threshold value, At this timing, it is considered that a current having an output amplitude value per one element of the IGBT has flown, and therefore it is determined that the IGBT is not in an open failure (step S305).

  On the other hand, in step S300, when it is not a period in which the switching circuit is controlled so that current flows out from the output terminal, the control circuit 25 is in a period in which the switching circuit is controlled so that current flows into the output terminal. Is determined (step S306). In step S306, when it is the period, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the negative terminal of the battery B2 (step S307). Thereafter, the output amplitude value of the switching circuit including the IGBT is obtained from the output current detected by the current sensor (step S308). Then, the control circuit 25 is configured such that, during the period, the current flowing through the IGBT is smaller than the output amplitude value per one element of the IGBT obtained by dividing the output amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group, and It is determined whether or not the difference between these currents is greater than or equal to a determination threshold (step S309).

  In step S309, when the current flowing through the IGBT during the period is smaller than the output amplitude value per IGBT element and the difference between the currents is equal to or greater than the determination threshold, the output amplitude per IGBT element Since it is considered that the current of the value does not flow, it is determined that the IGBT has an open failure (step S304). On the other hand, in step S309, when the current flowing through the IGBT during the period is smaller than the output amplitude value per IGBT element and the difference between the currents is not equal to or greater than the determination threshold value, At this timing, it is considered that a current having an output amplitude value per one element of the IGBT has flown, and therefore it is determined that the IGBT is not in an open failure (step S305).

  In step S306, when it is not a period in which the switching circuit is controlled so that current flows into the output terminal, the process returns to step S300.

  For example, during the period in which the control circuit 25 controls the switching circuit 210 so that current flows out from the output terminal, the output of the current sense terminal S of the IGBT 2100a constituting the IGBT group 2100 connected to the positive terminal of the battery B2 To obtain the current flowing through the IGBT 2100a. Thereafter, the output amplitude value of the switching circuit 210 including the IGBT 2100 a is obtained from the output current detected by the current sensor 23. Then, during this period, it is determined whether or not the current flowing through the IGBT 2100a is smaller than the output amplitude value per IGBT element, and the difference between the currents is equal to or greater than a determination threshold value. Here, the output amplitude value per element of the IGBT is a value obtained by dividing the output amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group 2100. When the current flowing through the IGBT 2100a is smaller than the output amplitude value per IGBT element during the period and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 2100a has an open failure, Otherwise, the IGBT 2100a determines that there is no open failure.

  On the other hand, during the period when the control circuit 25 controls the switching circuit 210 so that the current flows into the output terminal, the output of the current sense terminal S of the IGBT 2101a constituting the IGBT group 2101 connected to the negative terminal of the battery B2. To obtain the current flowing through the IGBT 2101a. Thereafter, the output amplitude value of the switching circuit 210 including the IGBT 2101 a is obtained from the output current detected by the current sensor 23. Then, during this period, it is determined whether or not the current flowing through the IGBT 2101a is smaller than the output amplitude value per IGBT element, and the difference between the currents is equal to or greater than a determination threshold value. Here, the output amplitude value per element of the IGBT is a value obtained by dividing the output amplitude value by the number of parallel connections of the IGBTs constituting the IGBT group 2101. When the current flowing through the IGBT 2101a is smaller than the output amplitude value per IGBT element during the period and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 2101a has an open failure. Otherwise, it is determined that the IGBT 2101a does not have an open failure.

  The control circuit 25 shown in FIG. 3 repeats the same processing and determines whether or not there is an open failure for all IGBTs in a normal operation state.

  Finally, the effect will be described. According to the third embodiment, the control circuit complementarily turns on the IGBTs constituting the two sets of IGBT groups connected in series so that the alternating current having the target amplitude value is output from the output terminal of the switching circuit. Turn off. The current output from the output terminal of the switching circuit is detected by a current sensor. During the period in which the control circuit 25 controls the switching circuit so that current flows out from the output terminal, the output amplitude value is given to the IGBTs constituting the IGBT group connected to the positive terminal of the battery B2 at any timing. Is divided by the number of IGBTs connected in parallel, and a current having an output amplitude value per IGBT element flows. On the other hand, during the period in which the control circuit 25 controls the switching circuit so that current flows into the output terminal, the IGBT that constitutes the IGBT group connected to the negative terminal of the battery B2 has any timing. A current having an output amplitude value per IGBT element flows. However, if the IGBT is in an open failure, a current having an output amplitude value per IGBT element does not flow through the IGBT even during the above-described period. Here, the current flowing through the IGBT is obtained based on the output of the current sense terminal S. Therefore, during the period when the switching circuit is controlled so that current flows out from the output terminal, the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the positive terminal of the battery B2 and the output detected by the current sensor On the other hand, during the period when the switching circuit is controlled so that the current flows into the output terminal, the current sense terminal S of the IGBT constituting the IGBT group connected to the negative terminal of the battery B2 is controlled. Based on the output and the output current detected by the current sensor, it can be directly determined whether or not the IGBT has failed. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in the motor control device 2 that is mounted on the vehicle and converts the DC power into the AC power to the three-phase AC motor M2 mounted on the vehicle, the open failure of the IGBT is directly identified and specified in the normal operation state. Can be detected.

  Further, according to the third embodiment, the control circuit 25 flows to the IGBTs constituting the IGBT group connected to the positive terminal of the battery B2 during the period in which the switching circuit is controlled so that the current flows from the output terminal. When the current is smaller than the output amplitude value per element of the IGBT and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT has an open failure, and the current flows into the output terminal. During the period when the switching circuit is controlled, the current flowing through the IGBTs constituting the IGBT group connected to the negative terminal of the battery B2 is smaller than the output amplitude value per IGBT element, and the difference between the currents is When it is equal to or greater than the determination threshold, it is determined that the IGBT has an open failure. Therefore, an open failure of the IGBT can be reliably detected.

  Furthermore, according to the third embodiment, the determination threshold value is set to a value that is not affected by the output error of the current sensors 23 and 24 so that the determination threshold value is not erroneously determined due to the influence of the output error of the current sensors 23 and 24. Is set. Therefore, it is possible to prevent erroneous determination due to output errors of the current sensors 23 and 24.

(Fourth embodiment)
Next, a motor control device according to a fourth embodiment will be described. In the motor control device of the fourth embodiment, the motor control device of the second embodiment is based on the output of the current sense terminal and the target current. While open faults were detected based on the output current detected by the sensor, open faults were detected based on the output of the current sense terminals of the IGBTs that make up the IGBT group. is there.

  Here, since the configuration of the motor control device of the fourth embodiment is the same as the configuration of the motor control device of the second embodiment, the description thereof is omitted.

  First, the operation of the motor control device will be described with reference to FIGS. The operation of the motor control device of the fourth embodiment is the same as the operation of the motor control device of the second embodiment except for the open failure detection operation of the IGBT. Therefore, an open failure detection operation of the IGBT will be described. Here, FIG. 6 is a flowchart for explaining an open failure detection operation of the IGBT in the motor control device of the fourth embodiment.

  As shown in FIG. 6, the control circuit 25 shown in FIG. 3 determines whether or not it is a period during which the switching circuit is controlled so that current flows from the output terminal (step S400). In step S400, the current flowing through the IGBT is obtained from the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the positive terminal of the battery B2 during the period (step S401). Thereafter, the control circuit 25 determines that the current flowing through one IGBT constituting the IGBT group connected to the positive terminal of the battery B2 is smaller than the current flowing through all the other IGBTs, and the current flowing through the one IGBT. It is determined whether or not the difference between the currents flowing through all other IGBTs is equal to or greater than the determination threshold value (step S402). Here, the determination threshold value is a threshold value for determining the current flowing through the one IGBT obtained from the output of the current sense terminal S and the current flowing through all other IGBTs based on the difference between the currents. It is. The determination threshold value is set to a value that is not affected by the output error of the current sense terminal S so as not to be erroneously determined due to the effect of the output error of the current sense terminal S.

  In step S402, the current flowing through one IGBT constituting the IGBT group connected to the positive terminal of the battery B2 is smaller than the current flowing through each of the other IGBTs, and the current flowing through the one IGBT and the other When the difference between the currents flowing in all the IGBTs is equal to or greater than the determination threshold value, it is determined that the one IGBT has an open failure (step S403). On the other hand, in step S402, the current flowing through one IGBT constituting the IGBT group connected to the positive electrode terminal of battery B2 is smaller than the current flowing through all other IGBTs and flows through the one IGBT. When the difference between the current and each of the currents flowing through all other IGBTs is not equal to or greater than the determination threshold value, it is determined that the one IGBT is not in an open failure (step S404).

  On the other hand, in step S400, when it is not a period in which the switching circuit is controlled so that current flows out from the output terminal, the control circuit 25 is in a period in which the switching circuit is controlled so that current flows into the output terminal. Is determined (step S405). In step S405, the current flowing through the IGBT is determined from the output of the current sense terminal S of the IGBT constituting the IGBT group connected to the negative terminal of the battery B2 during the period (step S406). Thereafter, the control circuit 25 determines that the current flowing in one IGBT constituting the IGBT group connected to the negative terminal of the battery B2 is smaller than the current flowing in all other IGBTs, and the current flowing in the one IGBT. Then, it is determined whether or not the difference between the currents flowing through all the other IGBTs is not less than the determination threshold value (step S407). Here, the determination threshold value is the same as the determination threshold value in step S402.

  In step S404, the current flowing in one IGBT constituting the IGBT group connected to the negative electrode terminal of battery B2 is smaller than the current flowing in all other IGBTs, and the current flowing in the one IGBT and the other When the difference between the currents flowing in all the IGBTs is equal to or greater than the determination threshold value, it is determined that the one IGBT has an open failure (step S403). On the other hand, in step S407, the current flowing through one IGBT constituting the IGBT group connected to the negative terminal of the battery B2 is smaller than the current flowing through all other IGBTs, and flows through the one IGBT. When the difference between the current and each of the currents flowing through all other IGBTs is not equal to or greater than the determination threshold value, it is determined that the one IGBT is not in an open failure (step S404).

  In step S405, when it is not the period during which the switching circuit is controlled so that current flows into the output terminal, the process returns to step S400.

  For example, during the period in which the control circuit 25 controls the switching circuit 210 so that current flows out from the output terminal, the current sense terminals S of the IGBTs 2100a and 2100b constituting the IGBT group 2100 connected to the positive terminal of the battery B2. The currents flowing in the IGBTs 2100a and 2100b are obtained from the output of. Thereafter, it is determined whether the current flowing through the IGBT 2100a is smaller than the current flowing through the IGBT 2100b and the difference between these currents is equal to or greater than a determination threshold value. If the current flowing through the IGBT 2100a is smaller than the current flowing through the IGBT 2100b and the difference between the currents is equal to or larger than the determination threshold, it is determined that the IGBT 2100a has an open failure, and otherwise, the IGBT 2100a has an open failure. Judge that it is not.

  On the other hand, during the period in which the control circuit 25 controls the switching circuit 210 so that current flows into the output terminal, the current sense terminals S of the IGBTs 2101a and 2101b constituting the IGBT group 2101 connected to the negative terminal of the battery B2. The currents flowing in the IGBTs 2101a and 2101b are obtained from the outputs of. Thereafter, it is determined whether the current flowing through the IGBT 2101a is smaller than the current flowing through the IGBT 2101b and the difference between the currents is equal to or greater than a determination threshold value. If the current flowing through the IGBT 2101a is smaller than the current flowing through the IGBT 2101b and the difference between the currents is equal to or greater than the determination threshold, it is determined that the IGBT 2101a has an open failure, and otherwise, the IGBT 2101a has an open failure. Judge that it is not.

  The control circuit 25 shown in FIG. 3 repeats the same processing and determines whether or not there is an open failure for all IGBTs in a normal operation state.

  Finally, the effect will be described. According to the fourth embodiment, the control circuit 25 complementarily turns on the IGBTs constituting two sets of IGBT groups connected in series so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. Turn off. During the period in which the control circuit 25 controls the switching circuit so that current flows out from the output terminal, equal current flows through each of the IGBTs constituting the IGBT group connected to the positive terminal of the battery B2. On the other hand, during the period in which the control circuit 25 controls the switching circuit so that current flows into the output terminal, equal current flows through the IGBTs constituting the IGBT group connected to the negative terminal of the battery B2. It becomes. However, if one of the IGBTs constituting the IGBT group has an open failure, no current flows through the IGBT, while a larger current flows through the other IGBTs. That is, the current flowing through the IGBT is different between a normal time and an open failure. Here, the current flowing through the IGBT is obtained based on the output of the current sense terminal. Therefore, during the period in which the switching circuit is controlled so that current flows out from the output terminal, based on the output of the current sense terminal of the IGBT constituting the IGBT group connected to the positive terminal of the battery B2, During the period when the switching circuit is controlled so that the current flows into the output terminal, the IGBT has an open failure based on the output of the current sense terminals of the IGBTs constituting the IGBT group connected to the negative terminal of the battery B2. It can be directly determined whether or not. Moreover, since it is not necessary to turn on and off with a predetermined conduction pattern for detecting an abnormality as in the prior art, an open failure can be detected by specifying an element in a normal operation state. Therefore, in the motor control device 2 that is mounted on the vehicle and converts the DC power into the AC power to the three-phase AC motor M2 mounted on the vehicle, the open failure of the IGBT is directly identified and specified in the normal operation state. Can be detected.

  Further, according to the fourth embodiment, the control circuit 25 is one IGBT constituting the IGBT group connected to the positive terminal of the battery B2 during the period in which the switching circuit is controlled so that current flows out from the output terminal. When the current flowing in each of the other IGBTs is smaller than the currents flowing in all the other IGBTs and the difference between all the currents is equal to or greater than the determination threshold, it is determined that the IGBT has an open failure, and the current is output to the output terminal. During the period in which the switching circuit is controlled to flow, the current flowing to one IGBT constituting the IGBT group connected to the negative terminal of the battery B2 is smaller than the current flowing to all other IGBTs, and those When all the current differences are equal to or greater than the determination threshold, it is determined that the IGBT has an open failure. Therefore, an open failure of the IGBT can be reliably detected.

  In the first embodiment and the second embodiment, an example is described in which an open failure of the IGBT is determined based on the target amplitude value, but the present invention is not limited to this. Since the target amplitude value is determined based on the command signal and the rotation angle, the open failure of the IGBT may be determined based on at least one of them. In this case, the same effect can be obtained.

  In the first to fourth embodiments, an example in which an open failure is always determined in a normal operation state is described. However, the present invention is not limited to this. For example, when the target amplitude value is equal to or less than a predetermined value that may cause an erroneous determination, the determination of the IGBT open failure may not be performed. In this case, an erroneous determination of an open failure can be prevented.

  Further, in the second to fourth embodiments, the IGBT groups 2100, 2101, 2110, 2111, 2120, and 2121 that constitute the switching circuits 210 to 212 are configured by connecting two IGBTs in parallel. It is mentioned, but not limited to this. The IGBT group may be configured by connecting three or more IGBTs in parallel. What is necessary is just to be comprised by connecting the some IGBT in parallel.

DESCRIPTION OF SYMBOLS 1, 2 ... Motor control apparatus (power conversion device) 10, 20 ... Smoothing capacitor, 11, 21 ... Power conversion circuit, 110, 111, 112, 210, 211, 212 ... Switching circuit 110a, 110b, 111a, 111b, 112a, 112b ... IGBT (switching element), 2100, 2101, 2110, 2111, 2120, 2121 ... IGBT group (switching element group), 2100a, 2100b, 2101a, 2101b 2110a, 2110b, 2111a, 2111b, 2120a, 2120b, 2121a, 2121b ... IGBT (switching element), 12, 22 ... drive circuit, 13, 14, 23, 24 ... current sensor, 15, 25 ... Control circuit, B1, B2 ... Battery (electric ), M1, M2 ··· 3-phase AC motor (load device), R1, R2 ··· rotation angle sensor, C1, C2 ··· controller (external device)

Claims (14)

A switching circuit configured by connecting two switching elements in series, an input terminal being formed at both ends of the switching elements connected in series, an output terminal being formed at a series connection point, and the input terminal being connected to a power source;
The switching element connected to the positive terminal of the power source and the negative terminal of the power source, respectively connected to the control terminal of the switching element, so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. And a control circuit for complementarily turning on and off the connected switching elements;
In a power conversion device comprising:
The switching element has a current sense terminal that outputs a current according to the flowing current when the switching element is turned on and a current flows;
The control circuit controls the switching circuit so that current flows out from the output terminal, and outputs the current sense terminal of the switching element connected to the positive terminal of the power source and a target amplitude. And detecting the open failure of the switching element connected to the positive terminal of the power source, and controlling the switching circuit so that a current flows into the output terminal, the negative electrode of the power source A power conversion device that detects an open failure of the switching element connected to the negative terminal of the power supply based on an output of the current sense terminal of the switching element connected to the terminal and a target amplitude. .   The control circuit flows to the switching element connected to the positive terminal of the power source, which is obtained from the output of the current sense terminal, during a period in which the switching circuit is controlled so that current flows out from the output terminal. When the current is smaller than the target amplitude and the difference between the currents is greater than or equal to the determination threshold, it is determined that the switching element connected to the positive terminal of the power supply has an open failure, and the current is output to the output terminal. The current flowing through the switching element connected to the negative terminal of the power source, obtained from the output of the current sense terminal, is smaller than the target amplitude, and is obtained from the output of the current sense terminal during the period in which the switching circuit is controlled to flow When the current difference of the current is equal to or greater than the determination threshold, the switching element connected to the negative terminal of the power source is open. Power converter according to claim 1, characterized in that determined to be. Two sets of switching elements formed by connecting a plurality of switching elements are connected in series, input terminals are formed at both ends of the series connected switching elements, and output terminals are formed at series connection points. A switching circuit whose terminals are connected to the power supply;
The switching elements constituting the switching element group connected to the positive terminal of the power supply so that an alternating current having a target amplitude value is output from the output terminal of the switching circuit. A control circuit for complementarily turning on and off the switching elements constituting the switching element group connected to a negative electrode terminal of the element and the power source;
In a power conversion device comprising:
The switching element has a current sense terminal that outputs a current according to the flowing current when the switching element is turned on and a current flows;
The control circuit controls the switching circuit such that a current flows out from the output terminal, and the current sensing of the switching element constituting the switching element group connected to the positive terminal of the power source is performed. Based on the output of the terminal and the target amplitude, the switching circuit is configured to detect an open failure of the switching element constituting the switching element group connected to the positive terminal of the power source and to allow current to flow into the output terminal. During the period of controlling the negative terminal of the power source based on the output and the target amplitude of the current sense terminal of the switching element constituting the switching element group connected to the negative terminal of the power source Detecting an open failure of the switching elements constituting the switching element group connected to the Power converter, wherein the door.   The control circuit obtains the switching element group connected to the positive terminal of the power source, which is obtained from the output of the current sense terminal, during the period in which the switching circuit is controlled so that current flows out from the output terminal. When the current flowing through the switching element is smaller than the target amplitude value per element obtained by dividing the target amplitude by the number of parallel connections of the switching elements, and the difference between the currents is equal to or greater than a determination threshold, the power source During the period in which it is determined that the switching element constituting the switching element group connected to the positive electrode terminal is in an open failure and the switching circuit is controlled so that current flows into the output terminal. The switch constituting the switching element group connected to the negative terminal of the power source, obtained from the output of the sense terminal. When the current flowing through the switching element is smaller than a target amplitude value per element obtained by dividing the target amplitude by the number of switching elements connected in parallel, and the difference between the currents is equal to or greater than a determination threshold, the negative electrode of the power supply The power conversion device according to claim 3, wherein the switching element configuring the switching element group connected to a terminal is determined to have an open failure. Two switching element groups formed by connecting a plurality of switching elements are connected in series, input terminals are formed at both ends of the switching element groups connected in series, and output terminals are formed at series connection points. A switching circuit connected to the power supply;
A current sensor for detecting a current output from the output terminal of the switching circuit;
The switching element is connected to a control terminal and an output terminal of the current sensor, respectively, and based on a detection result of the current sensor, an alternating current having a target amplitude value is output from the output terminal of the switching circuit. complementarily turned on the switching elements constituting the switching element group that is connected to the negative terminal of said switching element and said power supply constituting the switching element group connected to the positive terminal of the power supply, and a control circuit for turning off,
In a power conversion device comprising:
The switching element has a current sense terminal that outputs a current according to the flowing current when the switching element is turned on and a current flows;
The control circuit controls the switching circuit such that a current flows out from the output terminal, and the current sensing of the switching element constituting the switching element group connected to the positive terminal of the power source is performed. Based on the output of the terminal and the output current detected by the current sensor, an open failure of the switching element constituting the switching element group connected to the positive terminal of the power source is detected, and the current is output to the output terminal. the said period of time that controls the switching circuit to flow, detected output of said current sensor and an output of the current sense terminal of the switching elements constituting the switching element group connected to said negative terminal of said power supply The switching element group connected to the negative terminal of the power supply based on the current Power conversion apparatus characterized by detecting the open failure of that the switching element.   The control circuit obtains the switching element group connected to the positive terminal of the power source, which is obtained from the output of the current sense terminal, during the period in which the switching circuit is controlled so that current flows out from the output terminal. The current flowing through the switching element is less than the output amplitude value per element obtained by dividing the output amplitude value obtained by the output current detected by the current sensor by the number of parallel connections of the switching elements, and When the difference between the currents is equal to or greater than a determination threshold, it is determined that the switching elements constituting the switching element group connected to the positive terminal of the power supply have an open failure, and current flows into the output terminal. The negative terminal of the power source obtained from the output of the current sense terminal during the period of controlling the switching circuit The output amplitude per element obtained by dividing the output amplitude value obtained by the current flowing through the switching elements constituting the connected switching element group from the output current detected by the current sensor by the number of parallel connections of the switching elements. And when the difference between the currents is equal to or greater than a determination threshold value, it is determined that the switching element constituting the switching element group connected to the negative terminal of the power supply has an open failure. The power converter according to claim 5, wherein Two sets of switching elements formed by connecting a plurality of switching elements are connected in series, input terminals are formed at both ends of the series connected switching elements, and output terminals are formed at series connection points. A switching circuit whose terminals are connected to the power supply;
A current sensor for detecting a current output from the output terminal of the switching circuit;
The switching element is connected to a control terminal and an output terminal of the current sensor, respectively, and based on a detection result of the current sensor, an alternating current having a target amplitude value is output from the output terminal of the switching circuit. complementarily turned on the switching elements constituting the switching element group that is connected to the negative terminal of said switching element and said power supply constituting the switching element group connected to the positive terminal of the power supply, and a control circuit for turning off,
In a power conversion device comprising:
The switching element has a current sense terminal that outputs a current according to the flowing current when the switching element is turned on and a current flows;
The control circuit controls the switching circuit such that a current flows out from the output terminal, and the current sensing of the switching element constituting the switching element group connected to the positive terminal of the power source is performed. Based on the output of the terminal, an open failure of the switching element constituting the switching element group connected to the positive terminal of the power source is detected, and the switching circuit is controlled so that current flows into the output terminal. The switching element group connected to the negative terminal of the power source based on the output of the current sense terminal of the switching element constituting the switching element group connected to the negative terminal of the power source during the period A power conversion characterized by detecting an open failure of the switching element constituting Location.   The switching circuit group connected to the positive terminal of the power source, obtained from the output of the current sense terminal, during a period in which the control circuit controls the switching circuit so that current flows out from the output terminal The current flowing through one of the switching elements constituting the current is smaller than the current flowing through all the other switching elements, and the current flowing through the one switching element and the current flowing through all the other switching elements When all of the differences are equal to or greater than the determination threshold, it is determined that one of the switching elements constituting the switching element group connected to the positive terminal of the power supply has an open failure, and current flows into the output terminal In the period during which the switching circuit is controlled, the output from the current sense terminal was obtained, The current flowing through one switching element constituting the switching element group connected to the negative electrode terminal of the power source is smaller than the current flowing through all the other switching elements, and flows through one switching element. One of the switching elements constituting the switching element group connected to the negative terminal of the power supply is open failure when the difference between the current and each of the currents flowing through all the other switching elements is equal to or greater than a determination threshold. The power conversion device according to claim 7, wherein it is determined that the power conversion is in progress.   The control circuit determines a target amplitude value based on a command input from an external device and a physical quantity indicating a state of the load device input from a load device connected to the output terminal of the switching circuit, 4. The open failure of the switching element is detected based on at least one of a command input from the external device and a physical quantity indicating a state of the load device. 5. The power converter device described in 1.   The power converter according to any one of claims 1 to 9, wherein the control circuit does not determine an open failure of the switching element when a target amplitude value is equal to or less than a predetermined value.   The power conversion device according to claim 6, wherein the determination threshold value is set so as not to be affected by an output error of the current sensor.   The power conversion device according to any one of claims 2, 4, 6, 8, and 11, wherein the determination threshold is set so as not to be affected by an output error of the current sense terminal. .   The power conversion apparatus according to claim 1, wherein the power conversion apparatus is mounted on a vehicle and converts DC power to AC power.   The power converter according to claim 13, wherein AC power is supplied to an AC motor mounted on the vehicle.

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