JP2015142452A - Motor drive device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To include a shut-down function of a power device in a drive device of electrical equipment utilizing the power device, and to further reduce the drive device in size.SOLUTION: The drive device includes: a switching element module 2 in which an inverter circuit 10 is formed; and a control device 3 which outputs a switching control signal. The switching element module 2 further includes: a detection result input terminal Tc to which a detection result Cin of an abnormality detection circuit 8 is inputted; and a protection circuit 6 that performs shut-down control on the basis of an input signal to the detection result input terminal Tc. The control device 3 is configured to output a shut-down command SD for stopping operating the switching element module 2 regardless of the detection result Cin of the abnormality detection circuit 8 and to the detection result input terminal Tc, the shut-down command SD is inputted in addition to the detection result Cin of the abnormality detection circuit 8.

Description

  The present invention relates to a motor drive device that includes an inverter circuit and drives an AC motor.

  In general, a semiconductor switching element called a power device having a large withstand power is used to drive an electric device such as a motor. When an abnormality such as overcurrent or overvoltage occurs in such a power device and a circuit using the power device, so-called shutdown control is performed. The shutdown control is control that cuts off power to the power device, or changes the switching control signal of the power device to an inactive state to turn the power device off. For example, Japanese Patent Laid-Open No. 2003-13497 (Patent Document 1) discloses an abnormality detection circuit and an overcurrent detection circuit in an IPM (intelligent power module) in which a plurality of power modules are integrated to form an inverter circuit. An example in which shutdown control is performed based on the detection result is disclosed (FIG. 1 and the like).

  As in Patent Document 1, an IPM configured to be able to perform a protection operation based on a detection result by an external detection circuit even if an abnormality detection circuit or an overcurrent detection circuit is not incorporated is also put into practical use. Has been. For example, in the driving apparatus 100 shown in FIG. 6, the voltage generated by the current flowing through the shunt resistor 800 connected to the outside of the IPM 200 is fed back. The protection circuit 600 in the IPM 200 is operated by the feedback input to control the input to the control terminal of the switching element, and the switching element is controlled to be in the off state. On the other hand, a command (shutdown control signal) for shutting down the inverter circuit may be given from a control device higher than the switching control signal generation circuit 300. In order to control the input to the control terminal of the switching element in response to this command, a gate IC 900 such as a bus buffer is often used as shown in FIG. By the way, when the electric device to be controlled using the IPM is small, it is natural that the drive device including the IPM is also required to be small. In order to reduce the size, it is preferable that the number of electronic components constituting the driving device is small. Therefore, a technique for reducing the size of the drive device at low cost while maintaining the shutdown function is desired.

JP 2003-134797 A

  In view of the above background, it is desired to provide a technology for further reducing the size of a drive device for an electric device using a power device, which has a shutdown function for the power device.

In view of the above problems, the characteristic configuration of the motor drive device according to the present invention is as follows:
A motor drive device that includes an inverter circuit and drives an AC motor,
A switching element module in which the inverter circuit is configured such that an arm configured to include an upper-stage switching element and a lower-stage switching element that are complementarily switched is provided corresponding to a plurality of phases of alternating current;
A control device that outputs a switching control signal that controls switching of the switching elements that constitute the inverter circuit, and
The switching element module further detects an abnormality of the inverter circuit based on a detection result input terminal to which a detection result of an abnormality detection circuit for detecting an abnormality of the inverter circuit is input, and an input signal to the detection result input terminal. A protective circuit for performing a shutdown control for controlling the switching element so as to shut off all of the arms of a plurality of phases when determined,
The control device is configured to output a shutdown command for stopping the operation of the switching element module regardless of the detection result of the abnormality detection circuit.
The detection result input terminal is that the shutdown command is input in addition to the detection result of the abnormality detection circuit.

  According to this configuration, switching is performed according to the shutdown command without requiring a relay circuit (for example, the bus buffer illustrated in FIG. 6) that can shut off the switching control signal by the shutdown command for stopping the operation of the switching element module. The element module can be caused to execute shutdown control. Therefore, a gate IC for installing a bus buffer or the like can be omitted, and the number of parts can be reduced to further reduce the size of the motor drive device. That is, according to this configuration, it is possible to further reduce the size of the drive device for the electric device using the power device while having a power device shutdown function.

  Here, the motor control device according to the present invention includes, as one aspect, the switching element module including an abnormal state signal output terminal that outputs a determination result based on an input to the detection result input terminal as an abnormal state signal, It is preferable that the control device is configured to receive the abnormal state signal and the detection result of the abnormality detection circuit. For example, when there is a relay circuit that can cut off a switching control signal by a shutdown command, as in the driving device illustrated in FIG. 6, the switching element module performs shutdown in a state in which normal operation (operation that is not shutdown control) is performed. be able to. However, in the configuration like the motor control device according to the present invention, when the shutdown command is input to the detection result input terminal, the switching element module executes the shutdown control. At this time, the switching element module outputs from the abnormal state signal output terminal an abnormal state signal indicating that an abnormality that causes the shutdown control to occur. When the control device receives this abnormal state signal, it cannot be determined whether the abnormal state signal is output from the abnormal state signal output terminal based on the detection result of the abnormality detection circuit or the shutdown command. However, if the control device is configured to receive the abnormal state signal and the detection result of the abnormality detection circuit, the state of the switching element module can be correctly determined. For example, if the detection result of the abnormality detection circuit indicates an abnormality and the abnormal state signal is active, the motor control device determines that the abnormality is detected by the abnormality detection circuit and the shutdown control is being executed, and the abnormality is detected. When the detection result of the detection circuit does not indicate an abnormality and the abnormal state signal is active, it can be determined that the shutdown control is being executed by the shutdown command.

Block diagram schematically showing a configuration example of a motor control device The block diagram which shows the comparative example of the motor control apparatus of FIG. 1 typically The flowchart which shows an example of the procedure which determines the state of IPM by a control apparatus. The flowchart which shows an example of the procedure which determines the state of IPM by a control apparatus. Block diagram schematically showing another configuration example of the motor control device The block diagram which shows typically the example of a basic structure of the motor control apparatus provided with the relay circuit (bus buffer) which can interrupt | block a switching control signal

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 schematically shows a configuration example of the motor control device 1. The motor M is a drive source of an electric oil pump (EOP) of an automobile, for example. The motor control device 1 includes a switching element module (IPM: intelligent power module) 2, a control device 3, and peripheral circuits (8, 11, 12, 19, 91, etc.). In FIG. 1, terminals indicated by squares on the left and right ends are terminals of the motor control device 1, for example, terminals of a connector provided on a board constituting the motor control device 1. As shown in FIG. 1, the IPM 2 as the switching element module has a plurality of arms each having an upper switching element 9a (9) and a lower switching element 9b (9) that are complementarily switched. An inverter circuit 10 is configured corresponding to the alternating current of the phases. In the present embodiment, the control device 3 is a logical operation processor such as a microcomputer. The control device 3 generates and outputs a switching control signal for controlling the switching of the switching elements 9 constituting the inverter circuit 10.

  The motor M operates by receiving power from a high-voltage power supply having a higher voltage than that of an electronic circuit such as a microcomputer. The high-voltage power supply is a DC high-voltage battery (not shown) having a positive electrode P and a negative electrode N, and the power supply voltage is, for example, several hundreds [V]. The motor control device 1 (inverter circuit 10) converts DC power supplied from the DC high-voltage battery into three-phase AC and supplies it to the motor M. A high voltage relay (not shown) is provided between the DC high voltage battery and the motor control device 1. The power supply from the DC high-voltage battery to the motor control device 1 is configured to be cut off by a high-voltage relay command from a control device (for example, a host control device) different from the control device 3.

  The switching element 9 is, for example, a power semiconductor element such as an insulated gate bipolar transistor (IGBT), a field effect transistor (FET), or a power transistor. Inside the IPM 2, the upper switching element 9 a is connected to the high voltage positive electrode P, and the lower switching element 9 b is connected to the high voltage negative electrode N. Although not shown, each switching element 9 is configured to include a free wheel diode in parallel. The control device 3 that generates and outputs the switching control signal has an operating voltage of 3.3 to 5 [V], for example. Accordingly, the voltage is insufficient to drive the switching element 9, and the switching control signal is input to the control terminal (for example, gate terminal) of the switching element 9 via the drive circuit 4.

  In the present embodiment, the drive circuit 4 is built in the IPM 2. The drive circuit 4 is operated by a drive power supply (drive power supply). The power supply voltage (Vcc) of the drive power supply is, for example, 15 to 20 [V]. The drive circuit 4 is provided with one common drive circuit (lower stage drive circuit 42) for the lower stage side switching element 9b since the negative electrode N serving as the ground side reference of the switching control signal is common. ing. On the other hand, since the output voltage to the motor M fluctuates individually for each phase, the upper switching element 9a does not determine the ground-side reference of the switching control signal. Therefore, the drive circuit (upper stage drive circuit 41) for the upper stage switching element 9a is provided for each phase. In FIG. 1, for simplification, they are integrated and shown as a drive circuit (upper side drive circuit 41). Note that the switching control signal generated by the control device 3 and input to the IPM 2 is a high-active signal, and the switching control signal for each switching element 9 in the IPM 2 (input terminal portion) passes through the resistor 5. Pulled down.

  The IPM2 has a function of responding to some abnormalities occurring in the IPM2. The protection circuit 6 shown in FIG. 1 controls the switching element 9 so as to shut off all of the arms of the plurality of phases when the abnormality of the inverter circuit 10 is determined based on the input signal to the detection result input terminal Tc. Performs shutdown control. In the present embodiment, the protection circuit 6 controls all the switching control signals of the lower-stage switching element 9b to an invalid state (a state in which the switching element 9 is controlled to be turned off). When all the lower switching elements 9b are turned off, all the arms of the inverter circuit 10 are turned off, and the supply of AC power to the motor M is cut off. The electric power generated by the motor M continuing to rotate by the inertial force is returned by a free wheel diode connected in parallel to each switching element 9.

  As described above, the protection circuit 6 performs shutdown control when determining an abnormality of the inverter circuit 10 based on the input signal to the detection result input terminal Tc. A detection result (Cin) of an abnormality detection circuit that detects an abnormality of the inverter circuit 10 is input to the detection result input terminal Tc. FIG. 1 illustrates an overcurrent detection circuit as the abnormality detection circuit. Here, a shunt resistor 8 is illustrated as an overcurrent detection circuit. The overcurrent generated in the inverter circuit 10 generates a voltage corresponding to the magnitude of the current when flowing through the shunt resistor 8. The protection circuit 6 performs the above-described shutdown control (protection operation) by determining the voltage received via the detection result input terminal Tc by, for example, a comparator (determination circuit) provided in the protection circuit 6. At the same time, the protection circuit 6 outputs the determination result based on the input to the detection result input terminal Tc as the abnormal state signal Fout via the abnormal state signal output terminal Tf.

  The IPM 2 also has a built-in circuit (drive power supply monitoring circuit) that detects a voltage drop in the power supply voltage (Vcc) of the drive power supply (not shown). The drive power supply monitoring circuit executes drive power supply voltage drop protection control when detecting a drop in the power supply voltage (Vcc) of the drive power supply. The drive power supply voltage drop protection control is a control for cutting off the switching control signal via the drive circuit 4. In consideration of the case where the voltage drops momentarily as the load increases temporarily, the drive power supply monitoring circuit has a built-in filter of several [μs] to several tens [μs]. It is preferable that

  A drive power supply monitoring circuit is provided for each drive circuit 4. As described above, the upper drive circuit 41 is provided for each phase. Therefore, the drive power supply monitoring circuit corresponding to the upper drive circuit 41 is provided for each phase. Since the lower drive circuit 42 is common to each phase, one drive power supply monitoring circuit is also provided. Each drive power supply monitoring circuit executes drive power supply voltage drop protection control for the corresponding drive circuit 4. By the way, as described above, the function of outputting the abnormal state signal Fout from the abnormal state signal output terminal Tf is added to the lower stage when overcurrent is detected. When the drive power supply monitoring circuit for the lower drive circuit 42 detects a voltage drop, the abnormal state signal Fout is similarly output from the abnormal state signal output terminal Tf.

  The abnormal state signal Fout is transmitted to the control device 3. When the abnormal state signal Fout is in the valid state, the control device 3 knows that some abnormality (in this case, an overcurrent (short circuit) or a voltage drop in the drive power supply) has occurred. The type of abnormality cannot be determined only by Fout. Therefore, as shown in FIG. 1, an overcurrent determination circuit 12 that determines the occurrence of overcurrent from the voltage across the shunt resistor 8 and a voltage monitor 19 that monitors the power supply voltage (Vcc) of the drive power supply are provided. It is preferable that the determination result (detection result) of this circuit is input to the control device 3. Based on the abnormal state signal Fout, the determination result of the overcurrent determination circuit 12, and the determination result of the voltage monitor 19, the control device 3 determines the type of abnormality and the behavior of the IPM 2 (operating state, specifically whether or not shutdown control is performed). Can know.

  By the way, the shutdown control of the inverter circuit 10 is not always executed when an abnormality occurs in the IPM 2. For example, when an event that requires stopping the electric oil pump occurs, a shutdown command (upper shutdown command SDin) may be issued by a control device higher than the control device 3. As shown in FIG. 1, such an upper shutdown command SDin is generally notified to the control device 3, and the control device 3 outputs a shutdown command SD to the IPM 2. However, in order to ensure urgency, as shown in FIG. 1, an OR gate (91) may be used to take a logical sum of the upper shutdown command SDin and the shutdown command SD.

  Since such a shutdown command SD is not caused by an abnormality in the IPM 2, in many cases, shutdown control is performed outside the IPM 2. For example, in the configuration shown in the comparative example of FIG. 2, the shutdown command SD is input to the relay circuit configured by the gate IC 90, and the switching control signal output from the control device 3 is interrupted. Specifically, the control terminal of the tristate buffer is disabled by the shutdown command SD, and the output of the tristate buffer becomes high impedance. Since the switching control signals are pulled down inside the input terminal of the IPM 2, all the switching control signals are in a low state, and the switching control signals of all the switching elements 9 are in an invalid state. Thereby, all the switching elements 9 of the inverter circuit 10 are turned off, and the inverter circuit 10 is shut down.

  However, if the shutdown control according to the host shutdown command SDin is performed using such a relay circuit by the gate IC 90, the circuit scale of the motor control device 1 increases. Therefore, in the present embodiment, without using such a relay circuit, the shutdown command SD is input to the detection result input terminal Tc in addition to the detection result (Cin) of the abnormality detection circuit (shunt resistor 8). The function is realized. That is, the shutdown control is executed using the protection circuit 6 of the IPM 2. As shown in FIG. 1, in addition to the detection result (Cin), the shutdown command SD is input to the detection result input terminal Tc, so that the OR of the detection result (Cin) and the shutdown command SD is obtained by the OR gate (11). Taken. Usually, 2 to 4 OR gates are included in one semiconductor package. As described above, when the OR gate (91) is used to take the logical sum of the upper shutdown command SDin and the shutdown command SD, there are 1 to 3 OR gates, so the circuit scale (implementation) The OR gate (11) can be added without affecting the scale / mounting area).

  Even when the shutdown control associated with the host shutdown command SDin is left to the protection circuit 6 of the IPM 2 as described above, the control device 3 does not recognize the type of abnormality or the behavior (operation state, specifically, the IPM 2). Whether there is shutdown control). Details will be described with reference to the flowcharts of FIGS.

  The flowchart of FIG. 3 shows an example ($ 1) when there is no shutdown command SD (upper shutdown command SDin), and the flowchart of FIG. 4 shows an example when there is a shutdown command SD (upper shutdown command SDin) ( $ 2). As shown in step # 1 and step # 11 of FIG. 3, when there is no shutdown command SD and there is no abnormal output from the IPM 2 (output in the valid state of the abnormal state signal Fout), the control device 3 performs the shutdown control. It is determined that normal control is being performed in the IPM 2.

  If there is an abnormal output from the IPM 2 (output in the valid state of the abnormal state signal Fout), the type of the abnormal state is determined (steps # 12 and # 13 in the broken line portion of FIG. 3). If it is determined that an overcurrent has occurred based on the determination result of the overcurrent determination circuit 12 (# 12), the control device 3 determines that the type of abnormal state is the occurrence of an overcurrent (# 14). On the other hand, when it is determined that the power supply voltage (Vcc) of the drive power supply is decreasing based on the determination result of the voltage monitor 19 (# 13), the control device 3 indicates that the abnormal state type is an abnormality of the drive power supply. It is determined that there is (# 15).

  On the other hand, when neither the overcurrent determination circuit 12 nor the voltage monitor 19 determines the occurrence of an abnormality despite the presence of an abnormal output from the IPM 2 (output in the valid state of the abnormal state signal Fout), the IPM 2 Is abnormal, for example, it is determined that there is at least an abnormality in the protection circuit 6 or the circuit that outputs the abnormal state signal Fout (# 16). When the control device 3 determines that there is an abnormality in the IPM 2, a high voltage provided between the DC high voltage battery and the motor control device 1 is used to cut off the power supply from the DC high voltage battery to the motor control device 1. A request to open a voltage relay (not shown) is output to the host controller (# 17).

  Next, an example ($ 2) when there is a shutdown command SD (upper shutdown command SDin) will be described. As shown in Step # 1 and Step # 21 of FIG. 4, when there is a shutdown command SD and there is no abnormal output from the IPM 2 (output in the valid state of the abnormal state signal Fout), the control device 3 has a detection result input terminal. It is determined that the shutdown control is not performed despite the shutdown command SD being input at Tc, and it is determined that the IPM 2 is abnormal (# 28). That is, it is determined that there is at least an abnormality in the protection circuit 6 and the circuit that outputs the abnormal state signal Fout. Then, in accordance with the abnormality of the IPM 2, a high voltage relay (not shown) provided between the DC high voltage battery and the motor control device 1 is opened in order to cut off the power supply from the DC high voltage battery to the motor control device 1. The request is output to the host control device (# 29).

  When the shutdown command SD in the valid state is input to the detection result input terminal Tc and the IPM 2 is performing a specified operation, the protection circuit 6 executes the shutdown control and outputs an abnormal output (abnormal state signal Fout) from the IPM 2. Output in the valid state). The control device 3 determines the type of the abnormal state (steps # 22 and # 23 in the broken line portion in FIG. 4). When it is determined that an overcurrent has occurred based on the determination result of the overcurrent determination circuit 12 (# 22), the control device 3 determines that the type of abnormal state is the occurrence of an overcurrent (# 24). On the other hand, if it is determined that the power supply voltage (Vcc) of the drive power supply is decreasing based on the determination result of the voltage monitor 19 (# 23), the control device 3 indicates that the abnormal state type is an abnormality of the drive power supply. It is determined that there is (# 25). In such a case, there is a possibility that the control device 3 redundantly outputs the shutdown command SD based on the determination result of the overcurrent determination circuit 12 or the determination result of the voltage monitor 19. As described above, the flow of “$ 2” overlaps because the shutdown command SD has already been output. However, since it is determined that the motor control device 1 is abnormal, a high voltage relay (not shown) Is released to the host controller (# 29).

  On the other hand, in the case where neither the overcurrent determination circuit 12 nor the voltage monitor 19 determines that an abnormality has occurred even though there is an abnormal output from the IPM 2 (output in the valid state of the abnormal state signal Fout), the shutdown is performed. It can be determined that the protection circuit 6 is performing shutdown control based on the command SD or the host shutdown command SDin. Therefore, it is determined that the IPM 2 is performing a prescribed operation (# 26). After receiving the determination result of step # 26, since it is not determined that the motor control device 1 is abnormal, a request to open a high voltage relay (not shown) is not output. In addition, even if it becomes any determination result of step # 24- # 26, it is the operation | movement state prescribed | regulated according to the shutdown command SD (or high-order shutdown command SDin).

  As described above, according to the motor control device 1 according to the present embodiment, it is possible to further reduce the size of the drive device for the electric device using the power device while having a power device shutdown function. . Comparing the motor control device 1 shown in FIG. 1 with the motor control device shown in FIG. 2 as a comparative example, it is clear that the motor control device 1 according to this embodiment is smaller. In addition, while the circuit scale can be reduced, as shown in FIGS. 3 and 4, the control device 3 can detect the type of abnormality and the behavior of the IPM 2 (operation state, specifically, shutdown control). Presence / absence).

[Other Embodiments]
Hereinafter, other embodiments of the present invention will be described. Note that the configuration of each embodiment described below is not limited to being applied independently, and can be applied in combination with the configuration of other embodiments as long as no contradiction arises.

(1) In the above description, an overcurrent detection circuit (shunt resistor 8) that detects an overcurrent is illustrated as an abnormality detection circuit that detects an abnormality of the inverter circuit 10. However, the abnormality detection circuit is not limited to the overcurrent detection circuit, and may be a temperature detection circuit having a temperature sensor for measuring the temperature of the IPM 2 as a core. The voltage monitor 19 can also be an abnormality detection circuit.

(2) FIG. 1 illustrates a mode in which the terminal voltage of the shunt resistor 8 is input to the detection result input terminal Tc. However, the output of the overcurrent determination circuit 12 may be input to the detection result input terminal Tc as illustrated in FIG. For example, depending on the electrical characteristics (for example, input threshold level) of the input terminal of the OR gate (11), the voltage value of the shunt resistor 8 generated by the overcurrent may not be recognized as a valid input. There is a possibility that a more stable circuit can be configured by connecting the output of the digital value from the overcurrent determination circuit 12 having an OP amplifier or the like to the input terminal of the OR gate (11). Of course, it is also preferable to change the resistance value of the shunt resistor 8 so that the voltage value caused by the overcurrent sufficiently satisfies the electrical characteristics of the input terminal of the OR gate (11).

  The present invention can be used in a motor drive device that includes an inverter circuit and drives an AC motor.

1: Motor control device 3: Control device 6: Protection circuit 8: Shunt resistance (abnormality detection circuit)
9: Switching element 9a: Upper stage switching element (switching element)
9b: Lower stage side switching element (switching element)
10: Inverter circuit 12: Overcurrent determination circuit 19: Voltage monitor Fout: Abnormal state signal M: Motor SD: Shutdown command SDin: Host shutdown command Tc: Detection result input terminal Tf: Abnormal state signal output terminal

Claims (2)

A motor drive device that includes an inverter circuit and drives an AC motor,
A switching element module in which the inverter circuit is configured such that an arm configured to include an upper-stage switching element and a lower-stage switching element that are complementarily switched is provided corresponding to a plurality of phases of alternating current;
A control device that outputs a switching control signal that controls switching of the switching elements that constitute the inverter circuit, and
The switching element module further detects an abnormality of the inverter circuit based on a detection result input terminal to which a detection result of an abnormality detection circuit for detecting an abnormality of the inverter circuit is input, and an input signal to the detection result input terminal. A protective circuit for performing a shutdown control for controlling the switching element so as to shut off all of the arms of a plurality of phases when determined,
The control device is configured to output a shutdown command for stopping the operation of the switching element module regardless of the detection result of the abnormality detection circuit.
The detection result input terminal is a motor drive device to which the shutdown command is input in addition to the detection result of the abnormality detection circuit. The switching element module includes an abnormal state signal output terminal that outputs a determination result based on an input to the detection result input terminal as an abnormal state signal,
The motor drive device according to claim 1, wherein the control device is configured to receive the abnormal state signal and the detection result of the abnormality detection circuit.

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