JP6717695B2 - Power converter - Google Patents

Description

The present invention relates to a power conversion device.

Conventionally, an inverter with a winding switching function is known. For example, in Patent Literature 1, two sets of inverter circuits and two switches are provided to switch between Y-connection operation and Δ-connection operation.

JP-A-1-34198

Patent Document 1 does not mention the control sequence when switching between the Y connection operation and the Δ connection operation. Therefore, if the control switching timing and the switch opening/closing switching timing deviate from each other, an unintended increase in current or a voltage surge may occur.
The present invention has been made in view of the above problems, and an object thereof is to provide a power conversion device capable of appropriately switching between Y connection driving and Δ connection driving.

The power converter of the present invention converts power of a rotating electric machine (80) having coils (81, 82, 83) of a plurality of phases, and includes a first inverter (20) and a second inverter (30). And a high potential side connection line (51), a low potential side connection line (52), switches (52, 56), and a control unit (65).

The first inverter has a first upper arm element (21 to 23) provided on the high potential side and a first lower arm element (24 to 26) provided on the low potential side, and has one end of the coil (811, 821, 831) and a voltage source (40).
The second inverter has a second upper arm element (31 to 33) provided on the high potential side and a second lower arm element (34 to 36) provided on the low potential side, and the other end of the coil (812, 822). , 832).

The high potential side connecting line connects the positive side of the voltage source, the high potential side of the first upper arm element, and the high potential side of the second upper arm element.
The low potential side connecting line connects the negative side of the voltage source, the low potential side of the first lower arm element, and the low potential side of the second lower arm element.
The switch is provided on at least one of the high potential side connection line and the low potential side connection line, and can connect and disconnect the first inverter side and the second inverter side.

The control unit has an inverter control unit (651) and a switch control unit (652).
The inverter control unit controls the first inverter and the second inverter.
The switch controller 652 controls the open/closed state of the switch.

Here, the first inverter is controlled according to the drive request of the rotating electric machine, and the control state for neutralizing the second inverter is Y-controlled, and the switching states of different phases are synchronized between the first inverter and the second inverter. The control state is Δ control.
The control unit controls the inverter according to the open/closed state of the switch when switching between the Y connection drive that performs Y control when the switch is open and the Δ connection drive that performs Δ control when the switch is closed. Switch states.
As a result, it is possible to avoid a sharp increase in the phase current due to the switching between the Y connection driving and the Δ connection driving, and it is possible to appropriately switch between the Y connection driving and the Δ connection driving.

It is a schematic block diagram which shows the power converter device by 1st Embodiment of this invention. FIG. 3 is an explanatory diagram illustrating a drive area of the motor generator according to the first embodiment of the present invention. FIG. 3 is a circuit diagram illustrating (a) Y connection drive and (b) Δ connection drive according to the first embodiment of the present invention. 6 is a flowchart illustrating a switching process according to the first embodiment of the present invention. It is a circuit diagram explaining the zero vector control in the first embodiment of the present invention. 6 is a time chart illustrating a switching process according to the first embodiment of the present invention. 8 is a flowchart illustrating a switching process according to the second embodiment of the present invention. It is a circuit diagram explaining the switching process by 2nd Embodiment of this invention. 8 is a time chart illustrating a switching process according to the second embodiment of the present invention. It is a flowchart explaining the switching process by 3rd Embodiment of this invention. It is a circuit diagram explaining the switching process by 3rd Embodiment of this invention. It is a time chart explaining the switching process by 3rd Embodiment of this invention. It is a flowchart explaining the switching process by 4th Embodiment of this invention. It is a circuit diagram explaining the switching process by 4th Embodiment of this invention. It is a schematic block diagram which shows the power converter device by 5th Embodiment of this invention. It is a flowchart explaining the switching process by 5th Embodiment of this invention. It is a schematic block diagram which shows the power converter device by 6th Embodiment of this invention. It is a flowchart explaining the switching process by 6th Embodiment of this invention. It is a schematic block diagram which shows the power converter device by 7th Embodiment of this invention. It is a schematic block diagram which shows the power converter device by 8th Embodiment of this invention. It is a schematic block diagram which shows the power converter device by 9th Embodiment of this invention. It is a time chart explaining the case where an inverter control state and opening/closing of a switch switch simultaneously. It is a circuit diagram explaining the switching process by a reference example. 9 is a time chart illustrating a switching process according to a reference example.

Hereinafter, a power converter according to the present invention will be described with reference to the drawings. Hereinafter, in a plurality of embodiments, substantially the same configurations will be denoted by the same reference numerals, and description thereof will be omitted.
(First embodiment)
The power converter according to the first embodiment of the present invention is shown in FIGS.
As shown in FIG. 1, the rotary electric machine drive system 1 includes a power converter 11 and a motor generator 80 as a rotary electric machine.

The motor generator 80 is a so-called “main motor” that is applied to an electric vehicle such as an electric vehicle or a hybrid vehicle and generates torque for driving a drive wheel (not shown). The motor generator 80 has a function as an electric motor for driving the drive wheels and a function as a generator that is driven by kinetic energy transmitted from an engine (not shown) or the drive wheels to generate electric power. In the present embodiment, the case where the motor generator 80 functions as an electric motor will be mainly described.

The motor generator 80 is a three-phase AC rotating machine, and has a U-phase coil 81, a V-phase coil 82, and a W-phase coil 83. Hereinafter, the U-phase coil 81, the V-phase coil 82, and the W-phase coil 83 will be appropriately referred to as “coils 81, 82, 83”. A current flowing through the U-phase coil 81 is a U-phase current Iu, a current flowing through the V-phase coil 82 is a V-phase current Iv, and a current flowing through the W-phase coil 83 is a W-phase current Iw. Regarding the currents flowing through the coils 81 to 83, the current flowing from the first inverter 20 side to the second inverter 30 side is positive, and the current flowing from the second inverter 30 side to the first inverter 20 side is negative.

The power conversion device 11 converts the power of the motor generator 80, and includes the first inverter 20, the second inverter 30, the high-potential-side connection line 51, the low-potential-side connection line 55, the control unit 65, and the like. Prepare
The first inverter 20 is a three-phase inverter that switches the energization of the coils 81 to 83, and includes switching elements 21 to 26. The second inverter 30 is a three-phase inverter that switches the energization of the coils 81 to 83, and includes switching elements 31 to 36.
The switching element 21 has a transistor 211 and a diode 221. Similarly, the switching elements 22 to 26, 31 to 36 have transistors 212 to 216, 311 to 316, and diodes 222 to 226 and 321 to 326, respectively.

The transistors 211 to 216 and 311 to 316 are IGBTs (insulated gate bipolar transistors), and the on/off operation is controlled by the control unit 65. When the transistors 211 to 216 and 311 to 316 are turned on, energization from the high potential side to the low potential side is allowed, and when turned off, the energization is cut off. The transistors 211 to 216 and 311 to 316 are not limited to IGBTs, and may be MOSFETs or the like.

The diodes 221 to 226 and 321 to 326 are freewheeling diodes that are connected in parallel to the transistors 211 to 216 and 311 to 316, respectively, and allow energization from the low potential side to the high potential side. For example, the diodes 221 to 226 and 321 to 326 may be built in the transistors 211 to 216 and 311 to 316, such as a parasitic diode of MOSFET, or may be externally attached. ..

In the first inverter 20, the switching elements 21 to 23 are provided on the high potential side and the switching elements 24 to 26 are provided on the low potential side. The high potential side of the switching elements 21 to 23 is connected to the positive electrode of the battery 40, and the low potential side of the switching elements 24 to 26 is connected to the negative electrode of the battery 40.

One end 811 of the U-phase coil 81 is connected to the connection point of the U-phase switching elements 21 and 24, one end 821 of the V-phase coil 82 is connected to the connection point of the V-phase switching elements 22 and 25, and the W-phase One end 831 of the W-phase coil 83 is connected to the connection point of the switching elements 23 and 26 of. That is, the first inverter 20 is connected between the ends 811, 821, 831 of the coils 81, 82, 83 and the battery 40.

In the second inverter 30, the switching elements 31 to 33 are provided on the high potential side and the switching elements 34 to 36 are provided on the low potential side.
The other end 812 of the U-phase coil 81 is connected to the connection point of the U-phase switching elements 31 and 34, and the other end 822 of the V-phase coil 82 is connected to the connection point of the V-phase switching elements 32 and 35. The other end 832 of the W-phase coil 83 is connected to the connection point of the W-phase switching elements 33 and 36.

Hereinafter, in the first inverter 20, the switching elements 21 to 23 connected to the high potential side are “first upper arm elements”, and the switching elements 24 to 26 connected to the low potential side are “first lower arm elements” as appropriate. And In the second inverter 30, the switching elements 31 to 33 connected to the high potential side are referred to as “second upper arm elements”, and the switching elements 34 to 36 connected to the low potential side are referred to as “second lower arm elements”. To do.

The battery 40 is connected to the first inverter 20. In the present embodiment, a voltage source such as a battery is not provided on the second inverter 30 side.
The capacitor 43 is a smoothing capacitor connected between the first inverter 20 and the battery 40.
The current detector 45 detects the phase currents Iu, Iv, Iw. In the present embodiment, a current detection element such as a Hall element is provided for each phase as the current detection unit 45.

The high potential side connection line 51 connects the positive electrode side of the battery 40, the high potential side of the first upper arm elements 21 to 23, and the high potential side of the second upper arm elements 31 to 33. In other words, the high potential side connection line 51 is a connection wiring that connects the high potential side of the inverters 20 and 30 without passing through the motor generator 80.
The low potential side connection line 55 connects the negative electrode side of the battery 40, the low potential side of the first lower arm elements 24 to 26, and the low potential side of the second lower arm elements 34 to 36. In other words, the low potential side connection line 55 is a connection wiring that connects the low potential side of the inverters 20 and 30 without passing through the motor generator 80.

The high-potential side connection line 51 is provided with a high-potential side switch 52 capable of switching between conduction and interruption between the first inverter 20 side and the second inverter 30 side. A current sensor 521 is provided on the high potential side connection line 51. The current detected by the current sensor 521 is the high potential side switch current IswH. In the present embodiment, the open/closed state of the high potential side switch 52 is determined based on the high potential side switch current IswH.

The low-potential side connection line 55 is provided with a high-potential side switch 56 capable of switching between conduction and interruption between the first inverter 20 side and the second inverter 30 side. A current sensor 561 is provided on the low potential side connection line 55. The current detected by the current sensor 561 is the low potential side switch current IswL. In the present embodiment, the open/closed state of the high potential side switch 56 is determined based on the low potential side switch current IswL.
The switches 52 and 56 may be mechanical ones or semiconductor switches or the like as long as they can switch between conduction and interruption between the first inverter 20 side and the second inverter 30 side. In the present embodiment, the high potential side switch 52 and the low potential side switch 56 correspond to the “switch”. Hereinafter, the high-potential side switch 52 will be appropriately referred to as "upper side SW", and the low-potential side switch 56 will be referred to as "lower side SW". Further, in the figure, closing the SWs 52 and 56 is described as “ON”, and opening the SWs 52 and 56 is described as “OFF”.

The control signal generation unit 60 has a first driver circuit 61, a second driver circuit 62, and a control unit 65.
The control unit 65 is mainly composed of a microcomputer and performs various arithmetic processes. Each processing in the control unit 65 may be software processing by executing a program stored in advance by the CPU, or may be hardware processing by a dedicated electronic circuit.
The control unit 65 includes an inverter control unit 651, a switch control unit 652, a switching control unit 655 and the like.
The inverter control unit 651 controls the first inverter 20 and the second inverter 30. Specifically, based on command values related to driving the motor generator 80, such as the torque command value trq ^* and the current command values Iu ^* , Iv ^* , Iw ^*, etc., the transistors 211-216 of the switching elements 21-26, 31-36. , 311 to 316 are generated and output to the driver circuits 61 and 62.

The first driver circuit 61 generates and outputs a gate signal for controlling the on/off operation of the transistors 211 to 216 according to the control signal from the control unit 65. The second driver circuit 62 generates and outputs a gate signal for controlling the on/off operation of the transistors 311 to 316 according to the control signal from the control unit 65. By turning on/off the transistors 211 to 216 and 311 to 316 according to the control signal, the DC power of the battery 40 is converted into AC power and supplied to the motor generator 80. As a result, the drive of the motor generator 80 is controlled by the control unit 65 via the first inverter 20 and the second inverter 30.

Hereinafter, appropriately controlling the on/off operation of the transistors 211 to 216 and 311 to 316 of the switching elements 21 to 26, 31 to 36 is simply referred to as controlling the on/off operation of the switching elements 21 to 26, 31 to 36. In the present embodiment, the switching elements 21 to 26, 31 to 36 can be independently turned on and off by the driver circuits 61 and 62.

The switch controller 652 generates an open/close signal that controls opening/closing of the SWs 52 and 56, and outputs the open/close signal to the SWs 52 and 56.
The switching control unit 655 outputs an inverter control command to the inverter control unit 651 according to the high-potential-side switch current IswH and the low-potential-side switch current IswL, and a drive request to be described later, thereby changing the control state of the inverters 20 and 30. Control switching. In addition, the switching control unit 655 outputs a switch control command to the switch control unit 652 according to the high-potential side switch current IswH and the low-potential side switch current IswL, and a drive request described later, so that the SWs 52 and 56 are output. Controls switching between open and closed states.

The drive control of the motor generator 80 will be described. In the present embodiment, the rotation speed and torque of the motor generator 80 are “drive request”. As shown in FIG. 2, the drive region is divided into a Y connection drive region and a Δ connection drive region according to the rotation speed and torque of the motor generator 80. In the present embodiment, when the rotation speed N is equal to or lower than the rotation speed determination threshold Nth, the Y connection drive is performed, and when the rotation speed N is higher than the rotation speed determination threshold Nth, the Δ connection drive is performed. The boundary between the Y connection drive region and the Δ connection drive region can be appropriately set according to the rotation speed N, the torque trq, and the like.

When the rotation speed N and the torque trq are in the Y connection drive region, the control unit 65 controls the switching elements 21 to 26, 31 to 36 and the SWs 52 and 56 so that the coils 81 to 83 are in the Y connection state.
Specifically, the SWs 52 and 56 are opened.
The first inverter 20 is controlled according to a drive request of the motor generator 80, for example, by PWM control.
The second inverter 30 is turned to a neutral point by turning on all the phases of the second upper arm elements 31 to 33 or all the phases of the second lower arm elements 34 to 36 and turning the other off. Accordingly, it can be considered that the coils 81 to 83 are Y-connected.

For example, as shown in FIG. 3A, by turning on the upper arm elements 31 to 33 of the second inverter 30, the second inverter 30 side is neutralized, and the switching elements 21, 25 of the first inverter 20, When 26 is turned on, the current in the path indicated by arrow A1 flows.
The state in which the second upper arm elements 31 to 33 are turned on in all phases and the state in which the second lower arm elements 34 to 36 are turned on in all phases can be appropriately switched depending on, for example, the heat generation state of the elements. is there. By exchanging the elements that are turned on, heat generation can be dispersed.

When the rotation speed N and the torque trq are in the Δ-connection drive region, the control unit 65 controls the switching elements 21 to 26, 31 to 36 and the SWs 52 and 56 so that the coils 81 to 83 are in the Δ connection state.
Specifically, in the Δ connection drive, the SWs 52 and 56 are closed.
The control unit 65 controls the first inverter 20 and the second inverter 30 by PWM control or the like so that the switching states of the different phases of the first inverter 20 and the second inverter 30 are synchronized. Since the phases in which the switching states are synchronized have the same potential, the coils 81 to 83 can be regarded as equivalently Δ-connected.

In the Δ connection drive, for example, the U phase of the first inverter 20 (hereinafter, “U1 phase”), the W phase of the second inverter 30 (hereinafter, “W2 phase”), the V phase of the first inverter 20 (hereinafter, “ "V1 phase") and the U phase of the second inverter 30 (hereinafter "U2 phase"), the W phase of the first inverter 20 (hereinafter "W1" phase) and the V phase of the second inverter 30 (hereinafter "V2") The switching states of the phases are controlled so as to be synchronized.
For example, as shown in FIG. 3B, when the switching elements 21, 25, 26 of the first inverter 20 and the switching elements 33, 34, 35 of the second inverter 30 are turned on, the path indicated by the arrow A2. Current flows.
Further, for example, control may be performed so that the U1 phase and the V2 phase, the V1 phase and the W2 phase, and the W1 phase and the U2 phase are synchronized.
In FIG. 3, elements that are turned on are shown by solid lines, elements that are turned off are shown by broken lines, and energization paths are shown by two-dot chain arrows. Further, in FIG. 3, description of a part of the configuration such as the control signal generation unit 60 is omitted. The same applies to FIG. 5 and the like.

Here, switching between Y connection driving and Δ connection driving will be described. In the following description, the control state in which the first inverter 20 is controlled according to the drive request and the second inverter 30 is neutralized regardless of the states of the SWs 52 and 56 is “Y control”, and the first inverter 20 is controlled. The control state in which the switching states of different phases are synchronized between the second inverter 30 and the second inverter 30 is referred to as “Δ control”.

When switching between the Y connection driving and the Δ connection driving, it is necessary to switch the control states of the inverters 20 and 30 and the opening and closing of the SWs 52 and 56. Ideally, the inverter control state and the switch control state are switched at the same time. In this case, as shown in FIG. 22, when the open/closed states of the SWs 52 and 56 and the controlled states of the inverters 20 and 30 are simultaneously switched at time x91, the phase current does not rise and the voltage surge does not occur. The connection drive can be switched to the Δ connection drive. Although FIG. 22 shows the switching from the Y connection driving to the Δ connection driving, the same applies to the switching from the Δ connection driving to the Y connection driving.
In FIG. 22, (a) shows the phase current and (b) shows the driving state.

On the other hand, when the inverter control state and the switch control state are switched over and over, the switching timing may shift.
The reference examples shown in FIGS. 23 and 24 show an example in which the Y connection drive is switched to the Δ connection drive. In FIG. 24, (a) shows the phase current, (b) shows the open/close state of the upper SW 52, (c) shows the open/close state of the lower SW 56, and (d) shows the inverter control state. In the inverter control state, “MΔ” means Δ control, and “MY” means Y control. FIG. 24E is a diagram in which FIG. 23A is reduced in the vertical direction so that the entire phase current can be seen.

As shown in FIGS. 23A and 24, the driving state is Y connection driving until the time x95, and the second inverter 30 is turned on by turning on all the phases of the second lower arm elements 34 to 36. It is neutralized.
As shown in FIG. 23B, even if the upper SW 52 is turned on at time x95, the energized state does not change.
On the other hand, as shown in FIG. 23C, at time x96, when the lower SW 56 is turned on while the second lower arm elements 34 to 36 are in all phases on, a new energization path indicated by arrow AX is formed. I can do it. Therefore, the phase currents Iu, Iv, and Iw suddenly increase until the time x97 at which the control is switched to the Δ control (see FIG. 23D), and the control becomes impossible. Although not shown, when the upper SW 52 is turned on while the second inverter 30 is in the neutral point by turning on all the phases of the upper arm elements 31 to 33, the phase currents Iu and Iv. , Iw suddenly rises and becomes out of control.

Therefore, in the present embodiment, switching between Y connection driving and Δ connection driving is performed in order to avoid the loss of control as in the reference example.
The switching process of the present embodiment will be described based on the flowchart shown in FIG. In FIG. 4, this process is executed by the control unit 65 at a predetermined cycle. Hereinafter, the “step” of step S101 will be omitted and simply referred to as the symbol “S”. The same applies to the other steps.

In the first step S101, the rotation speed N and the torque trq of the motor generator 80 are input to the control unit 65 as drive point information.
In S102, the control unit 65 determines whether or not it is necessary to switch between the Y connection drive and the Δ connection drive. When it is determined that the switching is not necessary (S102: NO), the processing after S104 is not performed. When it is determined that the switching is necessary (S102: YES), the process proceeds to S103.

In S103, the switching control unit 655 determines whether or not the current drive state is Δ connection drive. If the current drive state is not Δ connection drive (S103: NO), that is, if the current drive state is Y connection drive, the process proceeds to S108. When the current drive state is the Δ connection drive (S103: YES), the process proceeds to S104.
When the current drive state is Δ connection drive, that is, when switching from Δ connection drive to Y connection drive, in S104, the switching control unit 655 issues a command to switch the switch control state to open. Output to the control unit 652. The switch controller 652 outputs a signal for opening the SWs 52 and 56 to the SWs 52 and 56.

In S105, the switching control unit 655 determines whether the switching of the SWs 52 and 56 to the open state is completed based on the switch currents IswH and IswL. In the present embodiment, when the high potential side switch current IswH is 0, it is determined that the SW 52 is open. When the low potential side switch current IswL is 0, it is determined that the switch 56 is open. Here, when the switch currents IswH and IswL are smaller than the determination threshold value Ith1 set according to the detection error or the like, the switch currents IswH and IswL are regarded as 0. When it is determined that both the SWs 52 and 56 have been switched to the open state (S105: YES), the process proceeds to S107. When it is determined that the switching of at least one of the SWs 52 and 56 is not completed (S105: NO), the process proceeds to S106.

In S106, the switching control unit 655 outputs a control command to the inverter control state to the zero vector control to the inverter control unit 651, and returns to S105. The inverter control unit 651 controls the inverters 20 and 30 to be in the zero vector state. In the present embodiment, control is performed such that one of all phases of the upper arm elements 21 to 23, 31 to 33 or one of all phases of the lower arm elements 24 to 26, 34 to 36 is turned on and the other is turned off (FIG. 5).

In FIG. 5A, zero vector control is performed by turning on the lower arm elements 24-26 and 34-36 and turning off the upper arm elements 21-23, 31-33. In FIG. 5B, zero vector control is performed by turning on the upper arm elements 21-23, 31-33 and turning off the lower arm elements 24-26, 24-36. In the zero vector control, electric power is not exchanged with the battery 40, and current flows back through the inverters 20, 30 and the motor generator 80. FIG. 5 shows an example in which the U-phase current Iu is positive and the V-phase current Iv and the W-phase current are negative, as indicated by the two-dot chain line arrow, but the current direction of each phase is zero vector control. Depending on the direction of energization immediately before switching to. Further, although FIG. 5 shows the energized state in which the SWs 52 and 56 are open, the same applies when at least one of the SWs 52 and 56 is closed.

FIG. 5 illustrates a case where one of the upper arm elements 21 to 23, 31 to 33 or one of the lower arm elements 24 to 26 and 34 to 36 is on and the other is off. The upper arm elements 21 to 23 may be turned on and the lower arm elements 34 to 36 may be turned on in the second inverter 30, or the lower arm elements 24 to 26 may be turned on in the first inverter 20 and the second inverter 30 may be turned on. The upper arm elements 31 to 34 may be on.

Returning to FIG. 4, when it is determined that the switching of the SWs 52 and 56 to the open state is completed (S105: YES), in S107, the switching control unit 655 issues a command to switch the inverter control state to the Y control. Output to the inverter control unit 651. The inverter control unit 651 performs Y control based on the driving point information so that the desired rotation speed N and torque trq are achieved. As a result, the drive state is switched to the Y connection drive.

When the current control state is Y connection drive, that is, when switching from Y connection drive to Δ connection drive, in S108, the switching control unit 655 issues a command to close the switch control state. It is output to the control unit 652. The switch controller 652 outputs a signal for closing the SWs 52 and 56 to the SWs 52 and 56.

In S109, the switching control unit 655 determines whether or not the switching of the SWs 52 and 56 to the closed state is completed based on the switch currents IswH and IswL. In the present embodiment, when the high potential side switch current Isw_H is not 0, it is determined that the SW 52 is closed. When the low potential side switch current Isw_L is 0, it is determined that the switch 56 is closed. Here, when the switch currents IswH and IswL are greater than or equal to the determination threshold value Ith2, it is considered that the switch currents IswH and IswL are not zero. The determination thresholds Ith1 and Ith2 may have the same value or different values. When it is determined that both the SWs 52 and 56 are completely closed (S109: YES), the process proceeds to S111. When it is determined that the switching of at least one of the SWs 52 and 56 is not completed (S109: NO), the process proceeds to S110.

In S110, similarly to S106, the switching control unit 655 outputs a control command for setting the inverter control state to the zero vector control to the inverter control unit 651, and returns to S109.
When it is determined that the switching of the SWs 52 and 56 to the closed state is completed (S109: YES), the switching control unit 655 instructs the inverter control unit 651 to switch the inverter control state to the Δ control in S111. Output. The inverter control unit 651 performs Δ control based on the drive point information so that the desired rotation speed N and torque trq are achieved. As a result, the drive state is switched to the Δ drive control.

The switching process of this embodiment will be described based on the time chart of FIG. In FIG. 6, (a) shows the phase current, (b) shows the open/closed state of the upper SW 52, (c) shows the open/closed state of the lower SW 56, and (d) shows the inverter control state. “M0” in the inverter control state means zero vector control. The same applies to FIGS. 9 and 12.
When it is necessary to switch from the Y connection drive to the Δ connection drive at time x11, a command to switch the SWs 52 and 56 from closed to open is output, and the inverter control state is set to the zero vector control. The zero vector control is continued until the time x12 when the switching of the SWs 52 and 56 to the closed state is completed.

As a result, as shown in FIG. 6A, it is possible to switch between the Y connection driving and the Δ connection driving without causing the phase currents Iu, Iv, and Iw to rapidly increase. Further, the zero vector control is performed between the Y control and the Δ control so that the opening and closing of the SW52 and 56 is switched during the zero vector control, thereby suppressing the occurrence of the voltage surge accompanying the switching of the opening and closing of the SW52 and 56. can do.
In FIG. 6, the upper SW 52 is closed first, and then the lower SW 56 is closed. However, if the inverter control state is zero vector control, the switching order of SW 52 and 56 is reversed. It doesn't matter.

As described above, the power conversion device 11 of the present embodiment converts the power of the motor generator 80 having the coils 81, 82, 83 of multiple phases, and includes the first inverter 20 and the second inverter 30. A high potential side connection line 51, a low potential side connection line 55, and a control unit 65.

The first inverter 20 has a plurality of first upper arm elements 21 to 23 provided on the high potential side and a plurality of first lower arm elements 24 to 26 provided on the low potential side, and includes coils 81, 82, and 83. It is connected to one ends 811, 821, 831 and the battery 40.
The second inverter 30 has a plurality of second upper arm elements 31 to 33 provided on the low potential side and a plurality of second lower arm elements 34 to 36 provided on the low potential side, and includes the coils 81, 82, 83. The other ends 812, 822, 832 are connected.

The high potential side connection line 51 connects the positive electrode side of the battery 40, the high potential side of the first upper arm elements 21 to 23, and the high potential side of the second upper arm elements 31 to 33.
The low potential side connection line 55 connects the negative electrode side of the battery 40, the low potential side of the first lower arm elements 24 to 26, and the low potential side of the second lower arm elements 34 to 36.
The switches 52 and 56 are provided on at least one of the high potential side connection line 51 and the low potential side connection line 55, and can connect and disconnect the first inverter 20 side and the second inverter 30 side.

The control unit 65 has an inverter control unit 651 and a switch control unit 652.
The inverter control unit 651 controls the first inverter 20 and the second inverter 30. The switch controller 652 controls the open/close state of the switches 52 and 56.
Here, the control state in which the first inverter 20 is controlled in accordance with the drive request of the motor generator 80 and the second inverter 30 is set to the neutral point is referred to as Y control. Further, the control state that synchronizes the switching states of different phases in the first inverter 20 and the second inverter 30 is referred to as Δ control.

When switching the Y connection drive that performs Y control when the switches 52 and 56 are open and the Δ connection drive that performs Δ control when the switches 52 and 56 are closed, the control unit 65 switches the switch 52, The inverter control state is switched according to the open/close state of 56.
In the present embodiment, since the Y connection drive and the Δ connection drive are switched according to the drive area, the efficiency is improved. Further, by switching the inverter control state according to the open/close state of the switches 52, 56, it is possible to avoid a sudden increase in the phase currents Iu, Iv, Iw, and to appropriately switch between the Y connection drive and the Δ connection drive. You can

The inverter control unit 651 controls the first inverter 20 and the second inverter 30 with zero vector during the period from the output of the switching signal for switching the switching of the switches 52 and 56 to the completion of the switching of the switches 52 and 56. And In addition, the inverter control unit 651 switches to Y control or Δ control after it is determined that the opening/closing of the switch has been switched.
As a result, it is possible to appropriately prevent a sudden increase in the phase currents Iu, Iv, and Iw that accompany the switching between the Y connection drive and the Δ connection drive. Further, it is possible to suppress the occurrence of a voltage surge that accompanies the switching between the Y connection drive and the Δ connection drive.

The high potential side connection line 51 and the low potential side connection line 55 are provided with current sensors 521 and 561 for detecting currents flowing through the switches 52 and 56. The control unit 65 determines the open/closed state of the switches 52, 56 based on the detection values of the current sensors 521, 561.
Thereby, the open/closed state of the switches 52 and 56 can be appropriately determined.

(Second embodiment)
The second embodiment of the present invention is shown in FIGS. Since the switching control is different between the second embodiment and the sixth embodiment, this point will be mainly described.
The switching process of this embodiment will be described based on the flowchart of FIG. 7.
The processing of S201 to S203 is the same as the processing of S101 to S103. When it is determined that the current drive state is the Δ connection drive (S203: YES), the process proceeds to S204, and when it is determined that the Y connection drive is performed (S203: NO), the process proceeds to S207.

In the process of S204, similarly to S104, the SW 52 and 56 are instructed to be opened.
The determination process in S205 is similar to S105, and when it is determined that the switching of at least one of the SWs 52 and 56 to the open state is not completed (S205: NO), this determination process is repeated. When it is determined that the switching of both the SWs 52 and 56 to the open state is completed (S205: YES), the process proceeds to S206.
In S206, the inverter control state is switched to Y control, as in S107.

When the current control state is the Y connection drive, that is, when the Y connection drive is switched to the Δ connection drive, the process of S207 is switched to the Δ control, similarly to S111.
In the process of S208, as in S108, the SW 52 and 56 are instructed to be closed.
The determination process in S209 is similar to S109, and when it is determined that the switching of at least one of the SWs 52 and 56 to the closed state is not completed (S209: NO), this determination process is repeated. When it is determined that the switching of both the SWs 52 and 56 to the closed state is completed (S209: YES), it is determined that the switching to the Δ connection drive is completed, and this processing is ended.

An example of switching from the Y connection drive to the Δ connection drive by the switching processing of the present embodiment will be described based on FIGS. 8 and 9.
As shown in FIG. 9 and FIG. 8A, the drive state until the time x21 is Y connection drive, and the second inverter 30 is turned on by turning on all the phases of the second lower arm elements 34 to 36. It is neutralized.
As shown in FIG. 8B, at time x21, the SW 52 and 56 are open, and the inverter control state is switched from Y control to Δ control. Even if the SW control is switched from the Y control to the Δ control with the SWs 52 and 56 in the open state, the energization path of each phase is secured, and the phase currents Iu, Iv, and Iw do not rise sharply.
When the upper SW 52 is closed at time x22 as shown in FIG. 8C and the lower SW 56 is closed at time x23 as shown in FIG. 8D, switching to the Δ connection drive is performed. Complete.

In the present embodiment, the SWs 52 and 56 are closed after the inverter control state is switched from Y control to Δ control. If the inverter control state is switched from Y control to Δ control, the phase currents Iu, Iv, and Iw do not suddenly increase even when the upper SW 52 and the lower SW 56 are closed. Although the upper SW 52 and the lower SW 56 are closed in this order in the examples of FIGS. 8 and 9, the order in which the SW 52 and 56 are closed does not matter as long as the inverter control state is switched to the Δ control.
As a result, as shown in FIG. 9A, it is possible to switch between the Y connection drive and the Δ connection drive without causing a sudden increase in the phase currents Iu, Iv, and Iw. Further, it is possible to switch between the Y connection drive and the Δ connection drive without reducing the torque.

When switching from Δ connection driving to Y connection driving, the inverter control unit 651 switches from Δ control to Y control after it is determined that the switches 52 and 56 have switched from closed to open.
When switching from Y connection drive to Δ connection drive, the switch control unit 652 switches the inverter control state from Y control to Δ control and then switches the switches 52 and 56 from open to closed.
As a result, Y control is not performed when the switches 52 and 56 are closed, so that a sudden increase in the phase currents Iu, Iv, and Iw can be appropriately avoided.
Moreover, the same effect as that of the above-described embodiment is obtained.

(Third Embodiment)
A third embodiment of the present invention is shown in FIGS. In the present embodiment, in the Y control, the lower arm elements 34 to 36 are turned on in all phases to make the second inverter 30 neutral.
The switching process of the present embodiment will be described based on the flowchart of FIG.
The processing of S301 to S303 is the same as the processing of S101 to S103. When it is determined that the current drive state is the Δ connection drive (S303: YES), the process proceeds to S304, and when it is determined that the Y connection drive is performed (S303: NO), the process proceeds to S308.
In S304, the switching control unit 655 outputs a command to switch the lower SW 56 to open to the switch control unit 652. The switch controller 652 outputs a signal for opening the lower SW 56 to the lower SW 56.

In S305, the switching control unit 655 determines whether the switching of the lower SW 56 to open is completed. When it is determined that the switching of the lower SW 56 to open has not been completed (S305: NO), this determination process is repeated. When it is determined that the switching of the lower SW 56 to the open state is completed (S305: YES), the process proceeds to S306.
In S306, the inverter control state is switched to Y control, as in S107.
In S307, the switching control unit 655 outputs a command to switch the upper SW 52 to open to the switch control unit 652. The switch controller 652 outputs a signal for opening the upper SW 52 to the upper SW 52.

When the current control state is Y connection drive, that is, when switching from Y connection drive to Δ connection drive, in S308, the switching control unit 655 issues a command to switch the upper SW 52 to close. Output to 652. The switch controller 652 outputs a signal for closing the upper SW 52 to the upper SW 52.
In S309, as in S111, the inverter control state is switched to Δ control.
In S310, the switching control unit 655 outputs to the switch control unit 652 a command to switch the lower SW 56 to close. The switch controller 652 outputs a signal for closing the lower SW 56 to the lower SW 56.

An example of switching from Y connection driving to Δ connection driving by the switching processing of the present embodiment will be described based on FIGS. 11 and 12.
As shown in FIG. 12 and FIG. 11A, the drive state until the time x31 is Y connection drive, and the second inverter 30 is turned on by turning on all the phases of the second lower arm elements 34 to 36. It is neutralized.
As shown in FIG. 11B, the energization path does not change even when the upper SW 52 is closed at time x31.
As shown in FIG. 11C, at time x32, the inverter control state is switched from Y control to Δ control. At this time, the energization path for each phase is secured, and the phase currents Iu, Iv, and Iw do not suddenly rise.
As shown in FIG. 11D, when the lower SW 56 is closed at time x33 after switching to Δ control, switching to Δ connection drive is completed. If the lower SW 56 is closed during the Y control, the phase currents Iu, Iv, and Iw suddenly increase. Therefore, in the present embodiment, the lower SW 56 is closed after the inverter control state is set to the Δ control. ..
When switching from Δ connection driving to Y connection driving, switching is performed in the order of FIGS. 11D, 11C, 11B, and 11A.

In the present embodiment, when switching from Δ connection drive to Y connection drive, the inverter control unit 651 switches the inverter control state from Δ control to Y control after it is determined that the lower SW 56 has switched from closed to open. At this time, in the Y control, the second lower arm elements 34 to 36 are turned on in all phases to make the second inverter 30 neutral.

In addition, when the second inverter 30 is neutralized by turning on all the phases of the second lower arm elements 34 to 36 by the Y connection drive, the inverter control unit 651 closes the upper SW 52 and then , The inverter control state is switched from Y control to Δ control. The switch control unit 652 closes the lower SW 56 after the inverter control state is switched from Y control to Δ control.

As a result, the lower side SW 56 does not close in the state where the second inverter 30 is in the neutral point by turning on all the phases of the second lower arm elements 34 to 36. Therefore, the phase current Iu , Iv, Iw can be appropriately avoided.
Moreover, the same effect as that of the above-described embodiment is obtained.

(Fourth Embodiment)
A fourth embodiment of the present invention is shown in FIGS. 13 and 14. In the present embodiment, in the Y control, the upper arm elements 31 to 33 are turned on in all phases to make the second inverter 30 neutral.
The switching process of the present embodiment will be described based on the flowchart of FIG.
The processing of S401 to S403 is the same as the processing of S101 to S103. If it is determined that the current drive state is Δ connection drive (S403: YES), the process proceeds to S404, and if it is determined to be Y connection drive (S403: NO), the process proceeds to S408.
In S404, as in S307, a command to open the upper SW 52 is output.

In S405, the switching control unit 655 determines whether or not the switching of the upper SW 52 to open is completed. When it is determined that the switching of the upper SW 52 to the open state is not completed (S405: NO), this determination process is repeated. When it is determined that the switching of the upper SW 52 to the open state is completed (S405: YES), the process proceeds to S406.
In S406, the inverter control state is switched to Y control, as in S107.
In S407, as in S303, a command to open the lower SW 56 is output.

When the current drive state is Y connection drive, that is, when switching from Y connection drive to Δ connection drive, in S408, as in S310, a command to close the lower SW 56 is output.
In S409, as in S111, the inverter control state is switched to Δ control.
In S410, as in S308, a command to close the upper SW 52 is output.

An example of switching from Y connection driving to Δ connection driving by the switching processing of the present embodiment will be described with reference to FIG.
As shown in FIG. 14A, in the present embodiment, the second inverter 30 is neutralized by turning on the second upper arm elements 31 to 33 in all phases.
As shown in FIG. 14B, even if the lower SW 56 is closed while the second upper arm elements 31 to 33 are in the on-state in all phases, the energization path does not change.
As shown in FIG. 14C, the inverter control state is switched from Y control to Δ control when the lower SW 56 is closed. At this time, the energization path for each phase is secured, and the phase currents Iu, Iv, and Iw do not suddenly rise.
As shown in FIG. 14D, when the upper SW 52 is set to the system after switching to the Δ control, the switching to the Δ connection drive is completed. When the upper SW 52 is closed during Y control, the phase currents Iu, Iv, and Iw suddenly rise. Therefore, in the present embodiment, the upper SW 52 is closed after the inverter control state is set to Δ control.
When switching from the Δ connection driving to the Y connection driving, the switching is performed in the order of FIGS. 14D, 14C, 14B, and 14A.

In the present embodiment, when switching from Δ connection driving to Y connection driving, the inverter control unit 651 switches the inverter control state from Δ control to Y control after it is determined that the upper SW 52 has switched from closed to open. At this time, in the Y control, the second upper arm elements 31 to 33 are turned on for all the phases, so that the second inverter 30 is set to the neutral point.

Further, in the Y connection drive, when switching from the neutralized state of the second inverter 30 to the Δ connection drive by turning on all the phases of the second upper arm elements 31 to 33, the inverter control unit 651, After closing the lower SW 56, the inverter control state is switched from Y control to Δ control. Further, the switch controller 652 closes the upper SW 52 after the inverter control state is switched from Y control to Δ control.

As a result, the upper SW 52 does not close in the state where the second inverter 30 is in the neutral point by turning on all the phases of the second upper arm elements 31 to 33, so that the phase current Iu, It is possible to appropriately avoid a sharp increase in Iv and Iw.
Moreover, the same effect as that of the above-described embodiment is obtained.

(Fifth Embodiment)
A fifth embodiment of the present invention is shown in FIGS. 15 and 16.
As shown in FIG. 15, the power conversion device 12 of the present embodiment is different from the above embodiments in that the lower SW 56 and the current sensor 561 are omitted.

The switching process of the present embodiment will be described based on the flowchart of FIG.
The processing of S501 to S503 is the same as the processing of S101 to S103. When it is determined that the current drive state is the Δ connection drive (S503: YES), the process proceeds to S504, and when it is determined that the Y connection drive is performed (S503: NO), the process proceeds to S507.
In S504, as in S307, a command to open the upper SW 52 is output.

In S505, similarly to S405, the switching control unit 655 determines whether or not the switching of the upper SW 52 to open is completed. When it is determined that the switching of the upper SW 52 to open has not been completed (S505: NO), this determination process is repeated. When it is determined that the switching of the upper SW 52 to the open state is completed (S505: YES), the process proceeds to S506.
In S506, the inverter control state is switched to Y control as in S107.

When the current drive state is Y connection drive, that is, when switching from Y connection drive to Δ connection drive, in S507, the inverter control state is switched to Δ control as in S111.
In S508, as in S308, a command to close the upper SW 52 is output.

In this embodiment, the inverters 20 and 30 cannot be separated on the low potential side. Therefore, at the time of Y connection driving, the upper side SW 52 is opened and the upper arm elements 31 to 33 are turned on in all phases, so that the second inverter 30 is made to have a neutral point.
When the Δ connection driving is switched to the Y connection driving, after the upper SW 52 is determined to be switched from the closed state to the open state, all the phases of the upper arm elements 31 to 33 are turned on, so that the second inverter 30 is neutralized. ..
When switching from Y connection drive to Δ connection drive, the upper SW 52 is closed after switching from Y control to Δ control.
As a result, it is possible to switch between the Δ connection drive and the Y connection drive without causing a sudden increase in the phase currents Iu, Iv, and Iw.
Moreover, the same effect as that of the above-described embodiment is obtained.

(Sixth Embodiment)
A sixth embodiment of the present invention is shown in FIGS. 17 and 18.
As shown in FIG. 17, the power conversion device 13 of the present embodiment is different from the above embodiments in that the upper SW 52 and the current sensor 521 are omitted.
The switching process of the present embodiment will be described based on the flowchart of FIG.
The processing of S601 to S603 is the same as the processing of S103 to S103. If it is determined that the current drive state is Δ connection drive (S603: YES), the process proceeds to S604, and if it is determined to be Y connection drive (S603: NO), the process proceeds to S607.
In S604, as in S303, a command to open the lower SW 56 is output.
In S605, the switching control unit 655 determines whether or not the switching of the lower SW 56 to open has been completed. When it is determined that the switching of the lower SW 56 to open has not been completed (S605: NO), this determination process is repeated. When it is determined that the lower SW 56 has been switched to the open state (S605: YES), the process proceeds to S606.
In S606, the inverter control state is switched to Y control, as in S107.

When the current drive state is Y connection drive, that is, when switching from Y connection drive to Δ connection drive, in S607, the inverter control state is switched to Δ control as in S111.
In S608, as in S310, a command to close the lower SW 56 is output.

In this embodiment, the inverters 20 and 30 cannot be separated on the high potential side. Therefore, at the time of the Y connection drive, the lower SW 56 is opened and all the phases of the lower arm elements 34 to 36 are turned on, so that the second inverter 30 becomes a neutral point.
When the Δ connection drive is switched to the Y connection drive, after the lower SW 56 is determined to be switched from the closed state to the open state, all the phases of the lower arm elements 34 to 36 are turned on, thereby making the second inverter 30 a neutral point. To do.
When switching from Y connection drive to Δ connection drive, the lower SW 56 is closed after switching from Y control to Δ control.
As a result, it is possible to switch between the Δ connection drive and the Y connection drive without causing a sudden increase in the phase currents Iu, Iv, and Iw.
Thereby, the same effect as that of the above-described embodiment is obtained.

(Seventh embodiment)
The seventh embodiment of the present invention is shown in FIG.
As shown in FIG. 19, the power conversion device 14 of the present embodiment is provided with voltage sensors 522 and 562 instead of the current sensors 521 and 561.
The high potential side voltage sensor 522 detects the voltage applied to the upper side SW52, and the voltage detected by the high potential side voltage sensor 522 is the high potential side switch voltage VswH. The switching control unit 655 determines the open/closed state of the upper SW 52 based on the high potential side switch voltage VswH. When the high potential side switch voltage VswH is equal to or higher than the determination threshold Vth, it is determined that the upper SW 52 is closed, and when it is lower than the determination threshold Vth, the upper SW 52 is determined to be open.

The low-potential side voltage sensor 562 detects the voltage applied to the lower SW 56, and the voltage detected by the low-potential side voltage sensor 562 is the low-potential side switch voltage VswL. The switching control unit 655 determines the open/closed state of the lower SW 56 based on the low potential side switch voltage VswL. When the low potential side switch voltage VswL is equal to or higher than the determination threshold Vth, it is determined that the lower SW 56 is closed, and when it is lower than the determination threshold Vth, the lower SW 56 is determined to be open.

The threshold value for determining the open state and the threshold value for determining the closed state may be different. Further, the threshold value for determining whether the upper SW 52 is open or closed may be different from the threshold value for determining whether the lower SW 56 is open or closed.
The switching process of this embodiment may be any of the processes of the first to fourth embodiments. Also, one of the SWs 52 and 56 may be omitted as in the fifth or sixth embodiment.
The same applies to the embodiments described later.

In the present embodiment, the high potential side connection line 51 and the low potential side connection line 55 are provided with voltage sensors 522 and 562 that detect the voltage applied to the switches 52 and 56. The control unit 65 determines the open/close state of the switches 52, 56 based on the detection values of the voltage sensors 522, 562.
Even with this configuration, the same effect as that of the above-described embodiment can be obtained.

(Eighth Embodiment)
FIG. 20 shows the eighth embodiment of the present invention.
As shown in FIG. 20, the power conversion device 15 of the present embodiment is provided with temperature sensors 523 and 563 instead of the current sensors 521 and 561.
The high-potential-side temperature sensor 523 detects the temperature of the upper SW 52, and the temperature detected by the high-potential-side temperature sensor 523 is the high-potential-side switch temperature TswH. The switching control unit 655 determines the open/closed state of the upper SW 52 based on the high potential side switch temperature TswH. When the high potential side switch temperature TswH is equal to or higher than the determination threshold Tth, it is determined that the upper SW 52 is closed, and when it is lower than the determination threshold Tth, the upper SW 52 is determined to be open.

The low-potential-side temperature sensor 563 detects the temperature of the lower SW 56, and the temperature detected by the low-potential-side temperature sensor 563 is the low-potential-side switch temperature TswL. The switching control unit 655 determines the open/closed state of the lower SW 56 based on the low potential side switch temperature TswL. When the low potential side switch temperature TswL is equal to or higher than the determination threshold Tth, it is determined that the lower SW 56 is closed, and when it is lower than the determination threshold Tth, the lower SW 56 is determined to be open.

In the present embodiment, the high potential side connection line 51 and the low potential side connection line 55 are provided with temperature sensors 523 and 563 that detect the temperatures of the switches 52 and 56. The control unit 65 determines the open/closed state of the switches 52, 56 based on the detection values of the temperature sensors 523, 563.
Even with this configuration, the same effect as that of the above-described embodiment can be obtained.

(9th Embodiment)
FIG. 21 shows a ninth embodiment of the present invention.
As shown in FIG. 21, in the power conversion device 16 of this embodiment, the current sensors 521 and 561 are omitted. The switching control unit 655 determines that the switching of the opening/closing of the upper SW 52 has been completed when the determination time Xth has elapsed since the command for switching the opening/closing of the upper SW 52 was output. Similarly, the switching control unit 655 determines that the switching of the opening/closing of the lower SW 56 is completed when the determination time Xth has elapsed since the command for switching the opening/closing of the lower SW 56 was output.
The determination time Xth is set according to the time required to switch between opening and closing of the switches 52 and 56 after the opening/closing signal is output. Further, the value for determining completion of switching from open to closed and the value for determining completion of switching from closed to open may be different.

The control unit 651 determines that the open/closed states of the switches 52, 56 are switched when the determination time Xth has elapsed after outputting the open/close signal for switching the switches 52, 56. Thereby, the sensor for determining the opening/closing of the SWs 52 and 56 can be omitted. Further, it is possible to determine the completion of the switching of the open/close of the SWs 52 and 56 without being affected by the surge of current and voltage.
Moreover, the same effect as that of the above-described embodiment is obtained.

(Other embodiments)
(A) Switching control For example, in the second embodiment, when switching from Δ connection driving to Y connection driving, the inverter control state is switched from Δ control to Y control after it is determined that the switch has been switched from closed to open. When switching from wire connection drive to Δ wire connection drive, the inverter control state is switched from Y control to Δ control, and then the switch is switched from open to closed. In another embodiment, one of switching from Δ connection driving to Y connection driving or switching from Y connection driving to Δ connection driving may be the switching control of a different embodiment. The same applies to the first, third, and fourth embodiments. That is, the switching control of different embodiments may be combined when switching from Δ connection driving to Y connection driving and when switching from Y connection driving to Δ connection driving.
In addition, in the second to fourth embodiments, the zero vector control may be performed from the time when the switching signal for switching the switching of the switch is output until the switching switching of the switch is completed.

(A) Voltage source In the above embodiment, a lithium ion battery or the like is illustrated as the voltage source. In other embodiments, the voltage source may be a lead acid battery other than a lithium ion battery, a fuel cell, or the like.
(C) Rotary Electric Machine In the above embodiment, the rotary electric machine is a motor generator. In another embodiment, the rotating electric machine may be a motor that does not have the function of a generator, or may be a generator that does not have the function of a motor. Further, the rotary electric machine of the above embodiment has three phases. In another embodiment, the rotating electric machine may have four or more phases.

Further, in the above embodiment, the rotating electric machine is the main motor of the electric vehicle. In other embodiments, the rotary electric machine is not limited to the main motor, but may be a so-called ISG (Integrated Starter Generator) having both a starter function and an alternator function, or an auxiliary motor. Further, the power conversion device may be applied to a device other than the vehicle.
As described above, the present invention is not limited to the above-described embodiment, and can be implemented in various forms without departing from the spirit of the invention.

11-16: Power converter 20... 1st inverter 21-23... 1st upper arm element 24-26... 1st lower arm element 30... 2nd inverter 31-33... 2 upper arm element 34-46... second lower arm element 40... battery (voltage source)
51... High potential side connection line 52... High potential side switch (switch)
55... Low potential side connection line 56... Low potential side switch (switch)
65... Control unit 651... Inverter control unit 652... Switch control unit 80... Motor generator (rotating electric machine)

Claims (12)

A power conversion device for converting the power of a rotating electric machine (80) having a plurality of phase coils (81, 82, 83),
A plurality of first upper arm elements (21 to 23) provided on the high potential side and a plurality of first lower arm elements (24 to 26) provided on the low potential side are provided, and one end (811, 821, 831) and a voltage source (40), and a first inverter (20),
It has a plurality of second upper arm elements (31 to 33) provided on the high potential side and a plurality of second lower arm elements (34 to 36) provided on the low potential side, and has the other ends (812, 822) of the coil. , 832) connected to a second inverter (30),
A high potential side connecting line (51) connecting the positive side of the voltage source, the high potential side of the first upper arm element, and the high potential side of the second upper arm element;
A low potential side connecting line (55) connecting the negative side of the voltage source, the low potential side of the first lower arm element, and the low potential side of the second lower arm element,
A switch (52, 56) provided on at least one of the high potential side connection line and the low potential side connection line and capable of connecting and disconnecting the first inverter side and the second inverter side,
A control unit (65) having an inverter control unit (651) for controlling the first inverter and the second inverter, and a switch control unit (652) for controlling the open/close state of the switch;
Equipped with
The control state of controlling the first inverter according to the drive request of the rotating electric machine to neutralize the second inverter is Y-controlled, and the switching states of different phases are synchronized between the first inverter and the second inverter. If the control state to be performed is Δ control,
When switching the Y connection drive that performs the Y control when the switch is open and the Δ connection drive that performs the Δ control when the switch is closed, the control unit determines whether the switch is opened or closed. A power conversion device that switches the inverter control state according to the inverter. The inverter control unit,
The power conversion device according to claim 1, wherein when the Δ connection drive is switched to the Y connection drive, the Δ control is switched to the Y control after it is determined that the switch is switched from closed to open. The inverter control unit,
When switching from the Δ connection driving to the Y connection driving, after it is determined that the switch (56) provided in the low potential side connection line has switched from closed to open, the Δ control is switched to the Y control,
The power conversion device according to claim 1, wherein, in the Y control, the second lower arm element is turned on in all phases to neutralize the second inverter. The inverter control unit,
When switching from the Δ connection drive to the Y connection drive, after it is determined that the switch (52) provided in the high potential side connection line is switched from closed to open, the Δ control is switched to the Y control,
The power conversion device according to claim 1, wherein, in the Y control, the second upper arm element is turned on in all phases to make the second inverter have a neutral point. The switch control unit switches the switch from open to closed after switching the inverter control state from the Y control to the Δ control when switching from the Y connection drive to the Δ connection drive. The power converter according to any one of 1. The switch is a high potential side switch (52) provided on the high potential side connection line, and a low potential side switch (56) provided on the low potential side connection line,
When switching from the neutralized state of the second inverter to the Δ connection driving by turning on all the phases of the second lower arm elements by the Y connection driving,
The inverter control unit switches the Y control to the Δ control after closing the high potential side switch,
The power converter according to claim 1, wherein the switch control unit closes the low potential side switch after the inverter control state is switched from the Y control to the Δ control. The switch is a high potential side switch (52) provided on the high potential side connection line, and a low potential side switch (56) provided on the low potential side connection line,
When switching from the neutralized state of the second inverter to the Δ connection driving by turning on all the phases of the second upper arm elements in the Y connection driving,
The inverter control unit switches the Y control to the Δ control after closing the low potential side switch,
The power converter according to claim 1, wherein the switch control unit closes the high potential side switch after the inverter control state is switched from the Y control to the Δ control. The inverter control unit,
The first inverter and the second inverter are set to zero vector control during a period from the output of the switching signal for switching the switching of the switch to the completion of switching of the switching of the switch,
The power conversion device according to any one of claims 1 to 7, which is switched to the Y control or the Δ control after it is determined that the opening/closing of the switch has been switched. A current sensor (521, 561) for detecting a current flowing through the switch is provided on the high potential side connection line and the low potential side connection line where the switch is provided,
The power conversion device according to claim 1, wherein the control unit determines the open/closed state of the switch based on a detection value of the current sensor. A voltage sensor (522, 562) for detecting a voltage applied to the switch is provided on the high potential side connecting line and the low potential side connecting line where the switch is provided,
The power converter according to any one of claims 1 to 8, wherein the control unit determines the open/closed state of the switch based on a detection value of the voltage sensor. 9. The control unit determines that the open/closed state of the switch has been switched when a determination time has elapsed after outputting an open/close signal for switching the open/close of the switch. Power converter. Temperature sensors (523, 563) for detecting the temperature of the switch are provided on the high potential side connection line and the low potential side connection line where the switch is provided,
The power conversion device according to any one of claims 1 to 8, wherein the control unit determines an open/closed state of the switch based on a detection value of the temperature sensor.

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