Multilevel inverter control device, program, and multilevel inverter

Abstract

To provide a multilevel inverter control device capable of suppressing a large voltage drop in a capacitor with which an electric device is connected in parallel.SOLUTION: A control device 50 is applied to an inverter 30, and is configured to control switches SUH to SWL and QU to QW so as to output any of voltages outputtable from a serial connection body of a first capacitor 21 and a second capacitor 22. A DCDC converter 40 and an electric compressor 41 are connected in parallel with the second capacitor 22. The control device 50 determines whether or not a suppliable current value for the DCDC converter 40 and the electric compressor 41 is less than a requested current value for the DCDC converter 40 and the electric compressor 41, and controls the switches SUH to SWL and QU to QW in such a way that current to flow to phase winding wires 13U to 13W of a rotary electric machine 10 in a case where the suppliable current value is determined to be less than the requested current value, is larger than that in a case where the suppliable current value is determined to be equal to or greater than the requested current value.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device for a multilevel inverter, a program, and a multilevel inverter. [Background technology]

[0002] As an example of this type of control device, Patent Document 1 describes a control device that turns on and off a switch of a three-level inverter. The three-level inverter includes a first capacitor and a second capacitor connected in series. The control device turns on and off the switch so that three levels of potential that can be output from the series connection of the first capacitor and the second capacitor are output to an armature winding of a rotating electric machine electrically connected to the switch. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-37592 Summary of the Invention [Problem to be solved by the invention]

[0004] In a three-level inverter, a power supply is connected in parallel to a series-connected first and second capacitors, and an electrical device is connected in parallel to either the first or second capacitor. In this case, if the current value supplied to the electrical device, which is powered by the power supply, falls below the current value required by the electrical device, the voltage of the capacitor connected in parallel to the electrical device may drop significantly. As a result, the electrical device may not operate properly.

[0005] The above-mentioned problem is not limited to three-level inverters, but also occurs in the case of multilevel inverters that output potentials at more than three levels.

[0006] A main object of the present invention is to provide a control device, a program, and a multilevel inverter that can suppress a large drop in voltage of a capacitor to which an electric device is connected in parallel. [Means for solving the problem]

[0007] The first configuration of the present invention comprises a plurality of capacitors connected in series, a switch electrically connected to the capacitor and an armature winding of a rotating electric machine, A control device for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power supply, An electric device can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, a determination unit that determines whether a current value that can be supplied to the electrical device is less than a current value required by the electrical device; and a control unit that, when it is determined that the supplyable current value is less than the required current value, controls the switch so that the current flowing through the armature winding is larger than when it is determined that the supplyable current value is equal to or greater than the required current value.

[0008] In the first configuration, a series-connected set of multiple capacitors is connected in parallel to a power supply, and a target capacitor, which is a portion of the multiple capacitors, is connected in parallel to an electrical device. In this case, if the current value supplied to the electrical device, which uses the power supply as a power source, falls below the required current value of the electrical device, the voltage of the target capacitor drops. To prevent the voltage drop of the target capacitor, power must be supplied to the target capacitor. However, the impedance of the DC component of the capacitor is very large. Therefore, although the series-connected set of multiple capacitors is connected in parallel to the power supply, the power that can be directly supplied from the power supply to the capacitor is very small, or cannot be directly supplied from the power supply to the capacitor. To supply sufficient power from the power supply to the target capacitor, power must be supplied from the power supply to the target capacitor via the inverter and the armature winding by controlling the switches provided in the multilevel inverter.

[0009] In consideration of this, in the control device of the first configuration, when it is determined that the current value that can be supplied to the electrical device is less than the required current value of the electrical device, the control device controls the switch to increase the current that flows through the armature winding compared to when it is determined that the current value that can be supplied is equal to or greater than the required current value. When the current value that flows through the armature winding increases, the current value that can be supplied to the target capacitor also increases. This makes it possible to suppress a voltage drop in the target capacitor.

[0010] A second configuration of the present invention includes a plurality of capacitors connected in series, a switch electrically connected to the capacitor and an armature winding of a rotating electric machine, A control device for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power supply, An electric device can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, a control unit that controls the switch so that the greater the required current value of the electrical equipment, the greater the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding.

[0011] According to the second configuration, the switches are controlled so that the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding increases as the required current value of the electrical device increases. This increases the current value supplied to the electrical device as the required current value increases, thereby making it possible to effectively suppress a voltage drop in the target capacitor. [Brief explanation of the drawings]

[0012] [Figure 1] Vehicle configuration diagram. [Figure 2] Control system configuration diagram. [Figure 3] FIG. 2 is a block diagram of a control unit that generates operation signals for each switch. [Figure 4] FIG. 4 is a diagram showing a method for setting a command current vector. [Figure 5] 4 is a flowchart showing a control procedure performed by the control device. [Figure 6] FIG. 4 is a diagram showing an example of a command current vector. [Figure 7] FIG. 4 is a diagram showing an example of auxiliary current supply control. [Figure 8] FIG. 4 is a diagram showing an example of auxiliary current supply control. [Figure 9] 4 is a time chart showing an example of auxiliary current supply control; [Figure 10] 6 is a time chart showing an example of control in a comparative example. [Figure 11] FIG. 10 is a diagram showing an example of auxiliary current supply control according to the second embodiment. [Figure 12] FIG. 4 is a diagram showing an example of auxiliary current supply control. [Figure 13] FIG. 10 is a configuration diagram of a control system according to another embodiment. [Figure 14] FIG. 10 is a configuration diagram of a vehicle according to another embodiment. [Figure 15] FIG. 10 is a configuration diagram of a control system according to another embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] First Embodiment A first embodiment of a control device according to the present invention will now be described with reference to the drawings. In this embodiment, the control device is mounted on an electrically powered vehicle such as an electric vehicle or a hybrid vehicle.

[0014] FIG. 1 shows a plan view illustrating a schematic configuration of a vehicle 100, and FIG. 2 shows a configuration diagram of a control system mounted on the vehicle 100. As shown in FIGS. 1 and 2, the vehicle 100 includes a rotating electric machine 10, a storage battery 20, and an inverter 30. The rotating electric machine 10 is an on-board main engine, and its rotor 11 is capable of transmitting power to drive wheels 12 of the vehicle. In this embodiment, the rotating electric machine 10 is a three-phase synchronous machine, and includes a star-connected U-phase winding 13U, a V-phase winding 13V, and a W-phase winding 13W as stator windings. The phase windings 13U, 13V, and 13W are arranged with an offset of 120° in electrical angle. The rotating electric machine 10 is, for example, a permanent magnet synchronous machine.

[0015] The storage battery 20 is electrically connected to the rotating electric machine 10 via the inverter 30. The storage battery 20 is a power source that supplies driving power to the rotating electric machine 10. In this embodiment, the storage battery 20 is, for example, a battery pack configured as a series connection of battery cells serving as single cells. For example, secondary batteries such as lithium ion batteries can be used as the battery cells. The terminal voltage of the storage battery 20 is, for example, 600 to 800 V.

[0016] The inverter 30 is a power conversion circuit that converts DC power supplied from the storage battery 20 into three-phase AC power by switching control and supplies the converted AC power to the rotating electric machine 10. A first capacitor 21 and a second capacitor 22 are provided on the storage battery 20 side of the inverter 30. The first capacitor 21 and the second capacitor 22 are connected in series. The storage battery 20 is connected in parallel to the series connection of the first and second capacitors 21 and 22. In this embodiment, the capacitance of the first capacitor 21 and the capacitance of the second capacitor 22 are set to the same value. The first capacitor 21 and the second capacitor 22 may be provided outside the inverter 30 or may be built into the inverter 30.

[0017] In this embodiment, the inverter 30 is a T-type three-level inverter. The inverter 30 includes three phases of series-connected upper-arm switches SUH, SVH, and SWH and lower-arm switches SUL, SVL, and SWL. A voltage-controlled semiconductor switching element, specifically an N-channel MOSFET, is used as each of the switches SUH to SWL. Therefore, the high-potential terminal of each of the switches SUH to SWL is the drain, and the low-potential terminal is the source. Each of the switches SUH, SVH, SWH, SUL, SVL, and SWL has a corresponding body diode DUH, DVH, DWH, DUL, DVL, or DWL.

[0018] The source of the U-phase upper arm switch SUH is connected to the drain of the U-phase lower arm switch SUL. The junction between the U-phase upper arm switch SUH and the U-phase lower arm switch SUL is connected to a first end of the U-phase winding 13U. The source of the V-phase upper arm switch SVH is connected to the drain of the V-phase lower arm switch SVL. The junction between the V-phase upper arm switch SVH and the V-phase lower arm switch SVL is connected to a first end of the V-phase winding 13V. The source of the W-phase upper arm switch SWH is connected to the drain of the W-phase lower arm switch SWL. The junction between the W-phase upper arm switch SWH and the W-phase lower arm switch SWL is connected to a first end of the W-phase winding 13W. The second ends of the phase windings 13U, 13V, and 13W are connected to each other.

[0019] The drains of the upper arm switches SUH to SWH are connected by a positive bus 31 such as a bus bar. The positive bus 31 is connected to the positive terminal of the storage battery 20 and a first end of the first capacitor 21. A second end of the first capacitor 21 is connected to a first end of the second capacitor 22 via a neutral point O. The sources of the lower arm switches SUL to SWL are connected by a negative bus 32 such as a bus bar. The negative bus 32 is connected to the negative terminal of the storage battery 20 and a second end of the second capacitor 22.

[0020] The inverter 30 includes clamp switches QU, QV, and QW that conduct and cut off current in both directions. In this embodiment, voltage-controlled semiconductor switching elements, specifically N-channel MOSFETs, are used as the switches that make up the clamp switches QU to QW. Each switch that makes up the clamp switches QU to QW has a corresponding body diode DU, DV, or DW.

[0021] Specifically, taking the U phase as an example, the sources of the switches that make up the U-phase clamp switch QU are connected to each other. Of the switches that make up the U-phase clamp switch QU, one drain is connected to the connection point between the U-phase upper arm switch SUH and the U-phase lower arm switch SUL, and the other drain is connected to the neutral point O. When turned on, the U-, V-, and W-phase clamp switches QU to QW allow bidirectional current flow, and when turned off, they block bidirectional current flow.

[0022] The vehicle 100 is equipped with a DC-DC converter 40 and an electric compressor 41 as "electrical equipment." The DC-DC converter 40 is driven to step down the output voltage of the storage battery 20 and supply power to a low-voltage battery (not shown, for example, a 12V auxiliary battery). The electric compressor 41 constitutes an interior air conditioning system and is driven by power supplied from the storage battery 20 to circulate refrigerant in the vehicle refrigeration cycle. In addition to the DC-DC converter 40 and the electric compressor 41, the vehicle 100 may also be equipped with a heater or other components as "electrical equipment." The heater is, for example, a PTC heater for heating.

[0023] In this embodiment, the DC-DC converter 40 and the electric compressor 41 are connected in parallel to the second capacitor 22. Specifically, a neutral terminal 42a is provided at the neutral point O, and a negative terminal 43a is provided at the negative bus 32 so that the DC-DC converter 40 and the electric compressor 41 can be connected in parallel to the second capacitor 22. Each terminal 42a, 43a is an external terminal for connecting the inverter 30 to an electrical device external to the inverter 30. The positive side of the electric compressor 41 is connected to the neutral terminal 42a via the neutral wiring 42. The positive side of the DC-DC converter 40 is connected to the neutral wiring 42. The negative side of the electric compressor 41 is connected to the negative terminal 43a via the negative wiring 43. The negative side of the DC-DC converter 40 is connected to the negative wiring 43. This reduces the voltage applied to the DC-DC converter 40 and the electric compressor 41 compared to when the DC-DC converter 40 and the electric compressor 41 are connected in parallel to the storage battery 20. In this embodiment, the second capacitor 22 corresponds to the "target capacitor."

[0024] 1 and 2 show a configuration in which a branch is made from the neutral point wiring 42 to connect the neutral point O and the positive electrode side of the DC-DC converter 40, but this is not limiting. For example, the inverter 30 may be provided with a plurality of connectors connectable to the neutral point O, and the positive electrode side of the DC-DC converter 40 and the positive electrode side of the electric compressor 41 may be connected to the connectors. Also, while FIGS. 1 and 2 show a configuration in which a branch is made from the negative electrode side wiring 43 to connect to the negative terminal of the storage battery 20 and the negative electrode side of the DC-DC converter 40, this is not limiting. For example, the storage battery 20 may be provided with a plurality of connectors connectable to the negative terminal of the storage battery 20, and the negative electrode side of the DC-DC converter 40 and the negative electrode side of the electric compressor 41 may be connected to the connectors.

[0025] The vehicle 100 includes a control device 50, a phase current sensor 51, a rotation angle sensor 52, an auxiliary current sensor 53, and a voltage sensor 54. The phase current sensor 51 detects U-, V-, and W-phase currents Iuvw flowing through the rotating electric machine 10. The phase current sensor 51 is required to detect at least two of the three-phase currents. The rotation angle sensor 52 is, for example, a resolver, and detects the electrical angle θe of the rotating electric machine 10. The auxiliary current sensor 53 detects the current flowing through the DC-DC converter 40 and the electric compressor 41. In this embodiment, the auxiliary current sensor 53 detects the current flowing through the neutral point wiring 42. The voltage sensor 54 detects the terminal voltage of the second capacitor 22. The detection values ​​of the sensors 51, 52, 53, and 54 are input to the control device 50. The vehicle 100 may also include a voltage sensor that detects the terminal voltage of the first capacitor 21.

[0026] The control device 50 is primarily composed of a microcomputer (corresponding to a "computer"), which includes a CPU. The functions provided by the microcomputer can be provided by software stored in a physical memory device and a computer that executes the software, by software alone, by hardware alone, or a combination of these. For example, when the microcomputer is provided by hardware electronic circuits, the functions can be provided by digital circuits including multiple logic circuits or analog circuits. For example, the microcomputer executes programs stored in a non-transitory tangible storage medium that serves as its own storage unit. The programs include, for example, programs for the processes shown in FIG. 5, etc. Execution of the programs results in the execution of a method corresponding to the programs. The storage unit is, for example, a non-volatile memory. The programs stored in the storage unit can be updated, for example, via a network such as the Internet.

[0027] The control device 50 generates drive commands to turn on and off each of the switches SUH to SWL, QU to QW of the inverter 30. Based on the generated drive commands, the control device 50 turns on and off each of the corresponding switches SUH to SWL, QU to QW. Below, with reference to FIG. 3, a process of generating drive commands for each of the switches SUH to SWL, QU to QW by the control device 50 will be described.

[0028] The control device 50 includes a command value setting unit 60. A command torque Trq* output from a higher-level control device (not shown) is input to the command value setting unit 60. The command value setting unit 60 sets a d-axis command current Id* and a q-axis command current Iq* in a two-phase rotating coordinate system (dq coordinate system) based on the command torque Trq*. In this embodiment, the command value setting unit 60 sets the d-axis command current Id* and the q-axis command current Iq* by minimum current maximum torque action (MTPA).

[0029] The control device 50 includes a three-phase conversion unit 61. A d-axis command current Id* and a q-axis command current Iq* are input to the three-phase conversion unit 61. The three-phase conversion unit 61 converts the d-axis command current Id* and the q-axis command current Iq* into U-, V-, and W-phase command currents Iuvw* in a three-phase fixed coordinate system based on the electrical angle θe. Note that the detection value of the rotation angle sensor 52 may be used as the electrical angle θe.

[0030] The control device 50 includes a deviation calculation unit 62. The deviation calculation unit 62 receives the U-, V-, and W-phase command currents Iuvw* and the U-, V-, and W-phase currents Iuvw. The deviation calculation unit 62 calculates a U-phase current deviation as a value obtained by subtracting the U-phase current from the U-phase command current. The deviation calculation unit 62 calculates a V-phase current deviation as a value obtained by subtracting the V-phase current from the V-phase command current. The deviation calculation unit 62 calculates a W-phase current deviation as a value obtained by subtracting the W-phase current from the W-phase command current. Note that the detection values ​​of the phase current sensors 51 may be used as the U-, V-, and W-phase currents Iuvw.

[0031] The control device 50 includes a feedback control unit 63. The U, V, and W-phase current deviations are input to the feedback control unit 63. Based on the U, V, and W-phase current deviations, the feedback control unit 63 calculates U, V, and W-phase command voltages Vuvw as manipulated variables for feedback-controlling the U, V, and W-phase currents Iuvw to U, V, and W-phase command currents Iuvw*. The feedback control may be, for example, proportional-plus-integral control.

[0032] The control device 50 includes a modulation unit 64. U-, V-, and W-phase command voltages Vuvw are input to the modulation unit 64. The modulation unit 64 generates operation signals for the switches SUH-SWL, QU-QW of the inverter 30 based on the U-, V-, and W-phase command voltages Vuvw. The modulation unit 64 may generate the operation signals for the switches SUH-SWL, QU-QW by, for example, space vector modulation control or triangular wave comparison PWM control.

[0033] However, if the current value supplied to the DC-DC converter 40 and the electric compressor 41, which use the storage battery 20 as a power supply source, falls below the current value required by the DC-DC converter 40 and the electric compressor 41, the voltage of the second capacitor 22 may drop significantly. As a result, the voltage of the second capacitor 22 falls below the lower limit voltage at which the DC-DC converter 40 and the electric compressor 41 can operate, and the DC-DC converter 40 and the electric compressor 41 may not be able to operate properly.

[0034] In order to suppress a voltage drop in the second capacitor 22, it is necessary to supply power to the second capacitor 22. Here, the impedance of the DC component of the capacitor is very large. For this reason, although the series connection of the first capacitor 21 and the second capacitor 22 is connected in parallel to the storage battery 20, the power that can be directly supplied from the storage battery 20 to the second capacitor 22 is very small, or power cannot be directly supplied from the storage battery 20 to the second capacitor 22. In order to supply a sufficient amount of power from the storage battery 20 to the second capacitor 22, it is necessary to supply power from the storage battery 20 to the second capacitor 22 via the inverter 30 and the respective phase windings 13U to 13W by controlling the respective switches SUH to SWL and QU to QW.

[0035] In view of this, in this embodiment, as shown in Fig. 4, the control device 50 increases the magnitude of the command current vector Ia determined from the d-axis command current Id* and the q-axis command current Iq* as the total value of the required current values ​​of the DC-DC converter 40 and the electric compressor 41 (hereinafter, required current value In) increases. In this case, as the magnitude of the command current vector Ia increases, the switches SUH to SWL and QU to QW are controlled so that the current supplied to the second capacitor 22 increases.

[0036] Depending on the driving conditions of the rotating electric machine 10, the switches SUH to SWL, QU to QW with a small magnitude of the command current vector Ia are controlled, and the current supplied to the DC-DC converter 40 and the electric compressor 41 using the storage battery 20 as a power supply source may fall below the required current value In. For example, in a situation where the running load is small, such as when the vehicle speed of the vehicle 100 is low or the torque of the rotating electric machine 10 is low, the magnitude of the command current vector Ia decreases, and the current supplied to the DC-DC converter 40 and the electric compressor 41 decreases. In this case, the supply current may fall below the required current value In. Therefore, in this embodiment, in a situation where the current supplied to the DC-DC converter 40 and the electric compressor 41 using the storage battery 20 as a power supply source may fall below the required current value In, the magnitude of the command current vector Ia is intentionally increased.

[0037] 5 shows the control procedure performed by the control device 50. This control is executed repeatedly, for example, at a predetermined control period.

[0038] In step S10, it is determined whether the supplyable current value Is to the DC-DC converter 40 and the electric compressor 41, which use the storage battery 20 as a power supply source, is equal to or greater than the required current value In of the DC-DC converter 40 and the electric compressor 41. In this embodiment, a value calculated based on the detection value of the phase current sensor 51 is used as the supplyable current value Is, and a value calculated based on the detection value of the auxiliary current sensor 53 is used as the required current value In. If the determination in step S10 is affirmative, the process proceeds to step S11. On the other hand, if the determination in step S10 is negative, the process proceeds to step S12.

[0039] The available supply current value Is may be calculated based on a value other than the detection value of the phase current sensor 51. For example, a value calculated based on the command torque Trq* or the detection value of the rotation angle sensor 52 may be used. The required current value In may be calculated based on a value other than the detection value of the auxiliary current sensor 53. For example, a preset value may be used as the required current value In. In this case, the more electrical devices, including the DC-DC converter 40 and the electric compressor 41, that are operating, the higher the required current value In may be variably set to.

[0040] In step S11, normal inverter control is performed. In this embodiment, in normal inverter control, a command torque Trq* is used as an input, and a d-axis command current Id* and a q-axis command current Iq* are set by minimum current maximum torque action (MTPA) control. The set d-axis command current Id* and q-axis command current Iq* are converted into U-, V-, and W-phase command currents Iuvw*, and U-, V-, and W-phase command voltages Vuvw are calculated as manipulated variables for feedback-controlling the U-, V-, and W-phase currents Iuvw*. Based on the U-, V-, and W-phase command voltages Vuvw, operation signals for the switches SUH-SWL and QU-QW of the inverter 30 are generated. As a result, the torque of the rotating electrical machine 10 is controlled to the command torque Trq*.

[0041] In step S12, auxiliary current supply control is performed. The auxiliary current supply control is control that generates operation signals for the switches SUH-SWL, QU-QW of the inverter 30 so as to increase the amplitude of the current flowing through the phase windings 13U-13W compared to normal inverter control. In this embodiment, the auxiliary current supply control controls the torque of the rotating electric machine 10 to the command torque Trq*, while increasing the magnitude of the command current vector Ia compared to normal inverter control.

[0042] Specifically, in the auxiliary current supply control, the d-axis command current Id* flowing through each phase winding 13U to 13W is increased, thereby increasing the magnitude of the command current vector Ia compared to normal inverter control. FIG. 6 illustrates an example of a command current vector Ia1 in normal inverter control and command current vectors Ia2 and Ia3 in the auxiliary current supply control. In the command current vectors Ia2 and Ia3 in the auxiliary current supply control, the d-axis command current Id* is increased on the negative side compared to the command current vector Ia1 in normal inverter control. In other words, in the auxiliary current supply control, the command current vectors Ia2 and Ia3 are set so that the field-weakening current is larger compared to normal inverter control. As a result, the magnitudes of the command current vectors Ia2 and Ia3 in the auxiliary current supply control are increased compared to the magnitude of the command current vector Ia1 in normal inverter control.

[0043] In the auxiliary current supply control, it is preferable to increase the magnitude of the command current vector Ia as the required current value In increases, as explained above in Fig. 4. For example, as shown in Fig. 6, it is preferable to set the command current vector in the auxiliary current supply control to Ia2 when the required current value In is small, and to set it to Ia3, which is the d-axis command current Id* increased to the negative side compared to Ia2, when the required current value In is large.

[0044] In the auxiliary current supply control, the d-axis command current Id* is increased, and the switches SUH-SWL and QU-QW are controlled so that the operating point determined by the d- and q-axis currents flowing through the phase windings 13U-13W is on the equal torque curve of the rotating electric machine 10 in the normal inverter control. For example, as shown in Fig. 6, the command current vectors Ia2 and Ia3 in the auxiliary current supply control are controlled to be on the equal torque curve A of the command current vector Ia1 in the normal inverter control.

[0045] In the auxiliary current supply control, when the rotor 11 of the rotating electrical machine 10 is not driven to rotate and is brought to a rotation-stop state, it is preferable to control the switches SUH-SWL and QU-QW so that only the d-axis current of the d- and q-axis currents flows through the phase windings 13U-13W. In this case, as shown in FIG. 6, the command current vector Ib in the auxiliary current supply control is controlled on the d-axis. This causes the q-axis current flowing through the phase windings 13U-13W to be zero, suppressing rotation of the rotor 11 of the rotating electrical machine 10 while increasing the current flowing through the phase windings 13U-13W. Note that the command current vector Ib in the auxiliary current supply control may be controlled so that the q-axis current has a value other than zero within a range in which the rotor 11 is allowed to rotate.

[0046] In controlling the auxiliary current supply, when the control device 50 stops the rotation of the rotor 11 of the rotating electric machine 10, it turns on the clamp switch of a specific phase among the U, V, and W phase clamp switches QU, QV, and QW determined according to the electrical angle θe of the rotating electric machine 10, turns off the lower arm switches SUL, SVL, and SWL of each phase, and turns on and off the upper arm switches of the phases other than the specific phase, thereby flowing a d-axis current through each phase winding 13U to 13W.

[0047] 7 and 8 show an example of auxiliary current supply control when the rotor 11 of the rotary electric machine 10 is brought into a rotation-stop state. Here, a case where the specific phase is the U phase will be described.

[0048] When the specific phase is the U phase, the U phase clamp switch QU is turned on, the V and W phase clamp switches QV and QW, the lower arm switches SUL to SWL of each phase, and the U phase upper arm switch SUH are turned off, and the V and W phase upper arm switches SVH and SWH are turned on and off.

[0049] 7 shows the current path when the V- and W-phase upper-arm switches SVH and SWH are turned on. In this case, current flows through a closed circuit including first capacitor 21, V- and W-phase upper-arm switches SVH and SWL, phase windings 13U to 13W, and U-phase clamp switch QU. This causes magnetic energy to accumulate in phase windings 13U, 13V, and 13W.

[0050] 8 shows the current path when the V- and W-phase upper-arm switches SVH and SWH are turned off. In this case, a closed circuit is formed including the second capacitor 22, DC-DC converter 40, electric compressor 41, V- and W-phase lower-arm diodes DVL and DWL, each phase winding 13U to 13W, and U-phase clamp switch QU, and current flows as the magnetic energy stored in each phase winding 13U, 13V, and 13W is released. This supplies power to the second capacitor 22, DC-DC converter 40, and electric compressor 41.

[0051] If the specific phase is the V phase, the V-phase clamp switch QV is turned on, the U- and W-phase clamp switches QU and QW, the respective phase lower arm switches SUL to SWL, and the V-phase upper arm switch SVH are turned off, and the U- and W-phase upper arm switches SUH and SWH are turned on and off.If the specific phase is the W phase, the W-phase clamp switch QW is turned on, the U- and V-phase clamp switches QU and QV, the respective phase lower arm switches SUL to SWL, and the W-phase upper arm switch SWH are turned off, and the U- and V-phase upper arm switches SUH and SVH are turned on and off.

[0052] When the specific phases are the U and V phases, the U and V phase clamp switches QU and QV are turned on, the W phase clamp switch QW, the lower arm switches SUL to SWL of each phase, and the U and V phase upper arm switches SUH and SVH are turned off, and the W phase upper arm switch SWH is turned on and off. When the specific phases are the V and W phases, the V and W phase clamp switches QV and QW are turned on, the U phase clamp switch QU, the lower arm switches SUL to SWL of each phase, and the V and W phase upper arm switches SVH and SWH are turned off, and the U phase upper arm switch SUH is turned on and off. When the specific phases are the U and W phases, the U and W phase clamp switches QU and QW are turned on, the V phase clamp switch QV, the lower arm switches SUL to SWL of each phase, and the U and W phase upper arm switches SUH and SWH are turned off, and the V phase upper arm switch SVH is turned on and off.

[0053] The specific phase is not necessarily fixed during the execution of the auxiliary current supply control, and may be variable. For example, an operation signal may be generated so that the U phase is the specific phase for half of one switching period of the auxiliary current supply control, and so that the U and V phases are the specific phases for the remaining period. The reason why the specific phase is variable during the execution of the auxiliary current supply control is that if an operation signal is generated so that the specific phase is fixed to the U phase, V phase, W phase, U and V phases, V and W phases, or U and W phases, depending on the position of the rotor 11, the q-axis current may not be zero.

[0054] Next, Fig. 9 shows an example of waveforms during auxiliary current supply control. In Fig. 9, (a) shows the change in voltage applied to U-phase winding 13U, (b) shows the change in voltage applied to V-phase winding 13V, (c) shows the change in voltage applied to W-phase winding 13W, (d) shows the change in current flowing through each phase winding 13U-13W, (e) shows the change in terminal voltage of second capacitor 22, and (f) shows the change in auxiliary current flowing through DC-DC converter 40 and electric compressor 41. Note that in Fig. 9, (a)-(c) show the phase voltages when the negative terminal of storage battery 20 is set to a reference potential (0 V), and in (d), the solid line indicates the current flowing through U-phase winding 13U and the dashed line indicates the current flowing through V- and W-phase windings 13V and 13W.

[0055] By performing the auxiliary current supply control, the current flowing through each phase winding 13U-13W is increased, thereby suppressing a large drop in the terminal voltage of the second capacitor 22. Here, it is preferable that the terminal voltage of the second capacitor 22 is controlled within an appropriate voltage range including a median value Vo (e.g., 400 V) of the terminal voltage (e.g., 800 V) of the series-connected body of the first capacitor 21 and the second capacitor 22. The upper limit voltage of the appropriate voltage range is preferably determined based on the allowable values ​​of the voltages applied to the DC-DC converter 40 and the electric compressor 41, and the lower limit voltage of the appropriate voltage range is preferably determined based on the voltages at which the DC-DC converter 40 and the electric compressor 41 can operate. Note that the appropriate voltage range may be determined based on the withstand voltages of the switches SUH-SWL and QU-QW.

[0056] Unlike this embodiment, Fig. 10 shows, as a comparative example, waveforms of normal inverter control when the command torque Trq* is 0. Figs. 10(a) to (f) correspond to Figs. 9(a) to (f).

[0057] In normal inverter control, when the command torque Trq* is 0, for example, the switches SUH-SWL and QU-QW are turned on and off synchronously so as to output the same voltage in each phase, and the current flowing through each phase winding 13U-13W is set to 0. Note that Figures 10(a)-(c) show the transition of each phase voltage when the clamp switches QU-QW and the lower arm switches SUL-SWL are alternately turned on.

[0058] When the current flowing through each of the phase windings 13U to 13W becomes zero, power is not supplied from the storage battery 20 to the second capacitor 22 via the inverter 30 and each of the phase windings 13U to 13W, causing a voltage drop in the terminal voltage of the second capacitor 22. As a result, there is a possibility that current cannot be supplied to the DC-DC converter 40 and the electric compressor 41.

[0059] According to the present embodiment described above in detail, the following effects can be obtained.

[0060] When it is determined that the supplyable current value Is to the DC-DC converter 40 and the electric compressor 41, which use the storage battery 20 as a power supply source, is less than the required current value In of the DC-DC converter 40 and the electric compressor 41, the switches SUH-SWL and QU-QW are controlled to increase the current flowing through the phase windings 13U-13W compared to when it is determined that the supplyable current value Is is equal to or greater than the required current value In. When the current flowing through the phase windings 13U-13W increases, for example, the period during which current is supplied to the second capacitor 22 in one electrical angle cycle becomes longer, and the current value that can be supplied to the second capacitor 22 also increases. Therefore, according to this embodiment, a voltage drop across the second capacitor 22 can be suppressed.

[0061] The larger the required current value In of the DC-DC converter 40 and the electric compressor 41, the larger the magnitude of the command current vector Ia is. In this case, as the magnitude of the command current vector Ia increases, the switches SUH to SWL and QU to QW are controlled so that the current supplied to the second capacitor 22 increases. As a result, the current value supplied to the DC-DC converter 40 and the electric compressor 41 increases as the required current value In increases, so that a voltage drop in the second capacitor 22 can be suitably suppressed.

[0062] When it is determined that the available current value Is is less than the required current value In, the switches SUH-SWL and QU-QW are controlled to increase the d-axis current value flowing through the phase windings 13U-13W compared to when it is determined that the available current value Is is equal to or greater than the required current value In. This makes it possible to intentionally increase the d-axis current and increase the current value supplied to the DC-DC converter 40 and the electric compressor 41. Furthermore, since an increase in the d-axis current value increases reactive current that does not contribute to torque generation, it becomes possible to prevent the actual torque of the rotor 11 from deviating significantly from the command torque Trq*.

[0063] The switches SUH-SWL, QU-QW are controlled to increase the d-axis current value, and the switches SUH-SWL, QU-QW are controlled so that the operating point determined by the d- and q-axis currents flowing through the phase windings 13U-13W is on the equal torque curve of the rotary electric machine 10 when it is determined that the supplyable current value Is is equal to or greater than the required current value In. This makes it possible to suppress torque fluctuations of the rotary electric machine 10 while suppressing a voltage drop in the second capacitor 22, and to prevent the user of the vehicle 100 from feeling uncomfortable.

[0064] When the vehicle 100 is stopped, the rotor 11 of the rotating electric machine 10 is not rotated, and the current value that can be passed through each of the phase windings 13U to 13W is small. Therefore, by allowing a d-axis current to flow during auxiliary current supply control when the rotor 11 is not driven to rotate, the current vector is increased and the current value that can be passed through each of the phase windings 13U to 13W is increased. As a result, the power that can be supplied to the second capacitor 22 can be ensured even when the vehicle is stopped.

[0065] In the auxiliary current supply control when rotor 11 is maintained in a rotation-stopped state, the q-axis current is set to 0. This suppresses the rotation of rotor 11, allowing vehicle 100 to be maintained in a stopped state and preventing the user of vehicle 100 from feeling uncomfortable.

[0066] Second Embodiment The second embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In this embodiment, instead of the second capacitor 22, a DC-DC converter 40 and an electric compressor 41 are connected in parallel to a first capacitor 21 (corresponding to a "target capacitor").

[0067] When the DC-DC converter 40 and the electric compressor 41 are connected in parallel to the first capacitor 21, if the current value supplied to the DC-DC converter 40 and the electric compressor 41 using the storage battery 20 as a power supply source falls below the required current value In of the DC-DC converter 40 and the electric compressor 41, the voltage of the first capacitor 21 may drop significantly. As a result, the DC-DC converter 40 and the electric compressor 41 may not be able to operate properly.

[0068] Therefore, in this embodiment, the control device 50 controls the switches SUH-SWL and QU-QW to supply power from the storage battery 20 to the first capacitor 21 via the inverter 30 and the phase windings 13U-13W. At this time, as shown in Fig. 4 above, the control device 50 may increase the magnitude of the command current vector Ia as the required current value In of the DC-DC converter 40 and the electric compressor 41 increases. As described above with reference to Figs. 5 and 6 above, the control device 50 may perform auxiliary current supply control when it determines that the supplyable current value Is is less than the required current value In.

[0069] In this embodiment, when the control device 50 maintains the rotor 11 of the rotating electric machine 10 in a stopped rotation state during auxiliary current supply control, it turns on the clamp switch in a specific phase determined according to the electrical angle θe of the rotating electric machine 10, turns off the upper arm switches in each phase, and turns on and off the lower arm switches in phases other than the specific phase, thereby causing a d-axis current to flow through each phase winding 13U to 13W.

[0070] 11 and 12 show an example of auxiliary current supply control when the rotor 11 is brought into a rotation-stop state. Here, a positive terminal 44a is provided on the positive bus 31 so that the DC-DC converter 40 and the electric compressor 41 can be connected in parallel to the first capacitor 21. The positive terminal 44a is an external terminal for connecting the inverter 30 to an electric device external to the inverter 30. The positive side of the electric compressor 41 is connected to the positive terminal 44a via a positive wiring 44. The positive side of the DC-DC converter 40 is connected to the positive wiring 44. The negative side of the electric compressor 41 is connected to a neutral terminal 42a via a neutral wiring 42. The negative side of the DC-DC converter 40 is connected to the neutral wiring 42. The case where the specific phase is a U phase will be described below.

[0071] When the specific phase is the U phase, the U phase clamp switch QU is turned on, the V and W phase clamp switches QV and QW, the upper arm switches SUH to SWH of each phase, and the U phase lower arm switch SUL are turned off, and the V and W phase lower arm switches SVL and SWL are turned on and off.

[0072] 11 shows the current path when the V- and W-phase lower arm switches SVL and SWL are turned on. In this case, current flows through a closed circuit including second capacitor 22, U-phase clamp switch QU, each phase winding 13U to 13W, and V- and W-phase lower arm switches SVL and SWL. This causes magnetic energy to be stored in each phase winding 13U, 13V, and 13W.

[0073] 12 shows the current path when the V- and W-phase lower-arm switches SVL and SWL are turned off. In this case, a closed circuit is formed including the first capacitor 21, DC-DC converter 40, electric compressor 41, U-phase clamp switch QU, each phase winding 13U to 13W, and V- and W-phase upper-arm diodes DVH and DWH, and current flows as the magnetic energy stored in each phase winding 13U, 13V, and 13W is released. This supplies power to the first capacitor 21, DC-DC converter 40, and electric compressor 41.

[0074] If the specific phase is the V phase, the V-phase clamp switch QV is turned on, the U- and W-phase clamp switches QU and QW, the respective phase upper arm switches SUH to SWH, and the V-phase lower arm switch SVL are turned off, and the U- and W-phase lower arm switches SUL and SWL are turned on and off.If the specific phase is the W phase, the W-phase clamp switch QW is turned on, the U- and V-phase clamp switches QU and QV, the respective phase upper arm switches SUH to SWH, and the W-phase lower arm switch SWL are turned off, and the U- and V-phase lower arm switches SUL and SVL are turned on and off.

[0075] When the specific phases are the U and V phases, the U and V phase clamp switches QU and QV are turned on, the W phase clamp switch QW, the upper arm switches SUH to SWH of each phase, and the U and V phase lower arm switches SUL and SVL are turned off, and the W phase lower arm switch SWL is turned on and off. When the specific phases are the V and W phases, the V and W phase clamp switches QV and QW are turned on, the U phase clamp switch QU, the upper arm switches SUH to SWH of each phase, and the V and W phase lower arm switches SVL and SWL are turned off, and the U phase lower arm switch SUL is turned on and off. When the specific phases are the U and W phases, the U and W phase clamp switches QU and QW are turned on, the V phase clamp switch QV, the upper arm switches SUH to SWH of each phase, and the U and W phase lower arm switches SUL and SWL are turned off, and the V phase lower arm switch SVL is turned on and off.

[0076] As in the first embodiment, the specific phase is not necessarily fixed during the execution of the auxiliary current supply control, but may be variable.

[0077] <Other embodiments> The above embodiment may be modified as follows, for example.

[0078] The control device 50 may be configured to periodically change the command current vector in the feedback control of the auxiliary current supply control. In this case, for example, the control device 50 may alternately set the command current vector between Ia2 and Ia3 shown in FIG. 6 in the auxiliary current supply control.

[0079] The inverter 30 is not limited to a T-type three-level inverter, and may be, for example, a neutral-point clamped three-level inverter. As shown in FIG. 13 , the inverter 30 includes first to fourth U-phase switches Su1 to Su4, first to fourth V-phase switches Sv1 to Sv4, first to fourth W-phase switches Sw1 to Sw4, and first to sixth clamp diodes Dc1 to Dc6. In this embodiment, voltage-controlled semiconductor switching elements, more specifically, IGBTs, are used as the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4. In this case, the high-potential side terminals of the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 are collectors, and the low-potential side terminals are emitters. For convenience, the same reference numerals are used in FIG. 13 for components identical to those shown in FIG. 2.

[0080] The U-phase first to fourth switches Su1 to Su4 are connected in series with their emitters connected to their collectors. The collector of the U-phase first switch Su1 is connected to the positive terminal of the storage battery 20 via a positive bus 31, and the emitter of the U-phase fourth switch Su4 is connected to the negative terminal of the storage battery 20 via a negative bus 32. A connection point between the U-phase second switch Su2 and the U-phase third switch Su3 is connected to a first end of the U-phase winding 13U of the rotating electrical machine 10. A cathode of a first clamp diode Dc1 is connected to the connection point between the U-phase first switch Su1 and the U-phase second switch Su2, and a cathode of a second clamp diode Dc2 is connected to the anode of the first clamp diode Dc1. A connection point between the U-phase third switch Su3 and the U-phase fourth switch Su4 is connected to the anode of the second clamp diode Dc2. Freewheel diodes Du1, Du2, Du3, and Du4 are connected in antiparallel to the U-phase switches Su1, Su2, Su3, and Su4, respectively.

[0081] The V-phase first to fourth switches Sv1 to Sv4 are connected in series with their emitters connected to their collectors. The collector of the V-phase first switch Sv1 is connected to the positive terminal of the storage battery 20 via a positive bus 31, and the emitter of the V-phase fourth switch Sv4 is connected to the negative terminal of the storage battery 20 via a negative bus 32. The connection point between the V-phase second switch Sv2 and the V-phase third switch Sv3 is connected to a first end of the V-phase winding 13V of the rotating electrical machine 10. The connection point between the V-phase first switch Sv1 and the V-phase second switch Sv2 is connected to the cathode of a third clamp diode Dc3, and the anode of the third clamp diode Dc3 is connected to the cathode of a fourth clamp diode Dc4. The anode of the fourth clamp diode Dc4 is connected to the connection point between the V-phase third switch Sv3 and the V-phase fourth switch Sv4. Freewheel diodes Dv1, Dv2, Dv3, and Dv4 are connected in antiparallel to the V-phase switches Sv1, Sv2, Sv3, and Sv4, respectively.

[0082] The W-phase first to fourth switches Sw1 to Sw4 are connected in series with their emitters connected to their collectors. The collector of the W-phase first switch Sw1 is connected to the positive terminal of the storage battery 20 via a positive bus 31, and the emitter of the W-phase fourth switch Sw4 is connected to the negative terminal of the storage battery 20 via a negative bus 32. A connection point between the W-phase second switch Sw2 and the W-phase third switch Sw3 is connected to a first end of the W-phase winding 13W of the rotating electrical machine 10. A cathode of a fifth clamp diode Dc5 is connected to the connection point between the W-phase first switch Sw1 and the W-phase second switch Sw2, and a cathode of a sixth clamp diode Dc6 is connected to an anode of the fifth clamp diode Dc5. A connection point between the W-phase third switch Sw3 and the W-phase fourth switch Sw4 is connected to an anode of the sixth clamp diode Dc6. Freewheel diodes Dw1, Dw2, Dw3, and Dw4 are connected in antiparallel to the W-phase switches Sw1, Sw2, Sw3, and Sw4, respectively.

[0083] A neutral point O is connected to the connection point of the first clamp diode Dc1 and the second clamp diode Dc2, the connection point of the third clamp diode Dc3 and the fourth clamp diode Dc4, and the connection point of the fifth clamp diode Dc5 and the sixth clamp diode Dc6.

[0084] As in the first embodiment, the control device 50 may control the switches Su1 to Su4, Sv1 to Sv4, and Sw1 to Sw4 so that the magnitude of the command current vector Ia increases as the required current value In of the DC-DC converter 40 and the electric compressor 41 increases. As in the first embodiment, the control device 50 may perform auxiliary current supply control when it is determined that the supplyable current value Is is less than the required current value In.

[0085] The connection manner of the storage battery 20, the inverter 30, the DC-DC converter 40, and the electric compressor 41 may be changed. For example, as shown in Fig. 14, in a configuration in which the neutral point O of the inverter 30 and the DC-DC converter 40 are connected via a neutral point wiring 42 and the negative side bus 32 and the DC-DC converter 40 are connected via a negative side wiring 43, the electric compressor 41 may be connected to the DC-DC converter 40. In this case, the DC-DC converter 40 may be provided with a connector that can be connected to the neutral point wiring 42 and a connector that can be connected to the negative side wiring 43, so that the electric compressor 41 can be connected to the DC-DC converter 40.

[0086] The inverter may be a multilevel inverter having four or more levels. Fig. 15 shows only the U-phase arm of a five-level inverter 70. Note that in Fig. 15, the control device is not shown, and the same components as those shown in Fig. 2 are denoted by the same reference numerals for convenience.

[0087] The inverter 70 includes first to eighth switches S1 to S8 and first to fourth capacitors 71 to 74. In this embodiment, an IGBT is used as each of the switches S1 to S8. Freewheel diodes D1, D2, D3, D4, D5, D6, D7, and D8 are connected in anti-parallel to the switches S1, S2, S3, S4, S5, S6, S7, and S8, respectively.

[0088] The first to fourth switches S1 to S4 are connected in series with their emitters and collectors connected. A series connection of first to fourth capacitors 71 to 74 is connected in parallel to the series connection of the first to fourth switches S1 to S4. The storage battery 20 is connected in parallel to the series connection of the first to fourth capacitors 71 to 74. Specifically, the positive terminal of the storage battery 20, the collector of the first switch S1, and the positive terminal of the first capacitor 71 are connected by a positive bus 75 such as a bus bar. The negative terminal of the storage battery 20, the emitter of the fourth switch S4, and the negative terminal of the fourth capacitor 74 are connected by a negative bus 76 such as a bus bar.

[0089] The collector of a fifth switch S5 is connected to the connection point between the first switch S1 and the second switch S2. The collector of a sixth switch S6 is connected to the emitter of the fifth switch S5. The connection point between the third switch S3 and the fourth switch S4 is connected to the emitter of the sixth switch S6. A first end of a U-phase winding 13U (not shown) is connected to the connection point between the fifth switch S5 and the sixth switch S6.

[0090] The emitters of the switches constituting the seventh switch S7 are connected to each other. Of the switches constituting the seventh switch S7, one collector is connected to the connection point between the first switch S1 and the second switch S2, and the other collector is connected to the connection point between the first capacitor 71 and the second capacitor 72. The emitters of the switches constituting the eighth switch S8 are connected to each other. Of the switches constituting the eighth switch S8, one collector is connected to the connection point between the third switch S3 and the fourth switch S4, and the other collector is connected to the connection point between the third capacitor 73 and the fourth capacitor 74. The connection point between the second switch S2 and the third switch S3 is connected to the connection point between the second capacitor 72 and the third capacitor 73.

[0091] In this embodiment, the DC-DC converter 40 and the electric compressor 41 are connected in parallel to a fourth capacitor 74, which serves as a "target capacitor." Specifically, the positive electrode side of the electric compressor 41 is connected to a connection point between the third capacitor 73 and the fourth capacitor 74 via a neutral point wiring 42, and the negative electrode side of the electric compressor 41 is connected to a negative bus 76 via a negative electrode side wiring 43. The positive electrode side of the DC-DC converter 40 is connected to the neutral point wiring 42, and the negative electrode side of the DC-DC converter 40 is connected to the negative electrode side wiring 43. In this case, the control device may control each of the switches S1 to S8 in consideration of the possibility of a large drop in the voltage of the fourth capacitor 74.

[0092] The DC-DC converter 40 and the electric compressor 41 may be connected in parallel to any of the first to fourth capacitors 71 to 74 except the fourth capacitor 74. Also, the DC-DC converter 40 and the electric compressor 41 may be connected in parallel to a series-connected capacitor assembly including any two or three of the first to fourth capacitors 71 to 74.

[0093] In the first and second embodiments, the drains of the clamp switches for each phase may be connected to each other instead of the sources being connected to each other. In this case, for example, of the switches constituting the U-phase clamp switch QU, the source of one may be connected to the connection point between the U-phase upper arm switch SUH and the U-phase lower arm switch SUL, and the source of the other may be connected to the neutral point O.

[0094] In the first embodiment, the semiconductor switches constituting the inverter 30 are not limited to N-channel MOSFETs and may be, for example, IGBTs. Also, in the configurations shown in Figures 13 and 15, the semiconductor switches constituting the inverter are not limited to IGBTs and may be N-channel MOSFETs.

[0095] The rotating electric machine is not limited to one in which the windings of each phase are star-connected, but may be one in which they are delta-connected.Furthermore, the rotating electric machine and inverter are not limited to one with three phases, but may be one with two phases or four or more phases.

[0096] The inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle, such as an aircraft or a ship. If the mobile body is an aircraft, the rotating electric machine serves as a power source for the aircraft's flight, and if the mobile body is a ship, the rotating electric machine serves as a power source for the ship's navigation. Furthermore, the inverter, rotating electric machine, and control device may be installed in a mobile body other than a vehicle.

[0097] The control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor and memory programmed to perform one or more functions embodied in a computer program. Alternatively, the control unit and the method described herein may be implemented by a special-purpose computer configured by configuring a processor with one or more dedicated hardware logic circuits. Alternatively, the control unit and the method described herein may be implemented by one or more special-purpose computers configured by combining a processor and memory programmed to perform one or more functions with a processor configured with one or more hardware logic circuits. Furthermore, the computer program may be stored as instructions executed by a computer on a computer-readable non-transitory tangible storage medium.

[0098] The following describes characteristic configurations extracted from the above-described embodiments. [Configuration 1] A plurality of capacitors (21, 22, 71 to 74) connected in series; The present invention is applied to a multilevel inverter (30, 70) including switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and an armature winding (13U to 13W) of a rotating electric machine (10), A control device (50) for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), an electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors; a determination unit that determines whether a current value that can be supplied to the electrical device is less than a current value required by the electrical device; a control unit that, when it is determined that the supplyable current value is less than the required current value, controls the switch so that the current flowing through the armature winding is larger than that when it is determined that the supplyable current value is equal to or greater than the required current value. [Configuration 2] The control device for a multilevel inverter according to configuration 1, wherein the control unit controls the switch so that the larger the requested current value, the larger the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding. [Configuration 3] A plurality of capacitors (21, 22, 71 to 74) connected in series; The present invention is applied to a multilevel inverter (30, 70) including switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and an armature winding (13U to 13W) of a rotating electric machine (10), A control device (50) for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), an electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors; A control device for a multilevel inverter, comprising: a control unit that controls the switch so that the greater the required current value of the electrical device, the greater the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding. [Configuration 4] 3. The control device for a multilevel inverter according to configuration 1 or 2, wherein, when it is determined that the supplyable current value is less than the required current value, the control unit controls the switch so that a d-axis current value to be passed through the armature winding is larger than when it is determined that the supplyable current value is equal to or greater than the required current value. [Configuration 5] 5. The control device for a multilevel inverter according to configuration 4, wherein the control unit controls the switch to increase the d-axis current value when it is determined that the supplyable current value is less than the required current value, and controls the switch so that an operating point determined by the d-axis and q-axis currents flowing through the armature winding is on an equal torque curve of the rotating electric machine when it is determined that the supplyable current value is equal to or greater than the required current value. [Configuration 6] The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), a three-level inverter including, as the switches, switches (SUH to SWL, QU to QW, Su1 to Sw4) that electrically connect the armature winding to any one of the positive side of the first capacitor, a neutral point between the negative side of the first capacitor and the positive side of the second capacitor, and the negative side of the second capacitor; 6. The control device for a multilevel inverter according to any one of configurations 1 to 5, which controls the switch so as to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor. [Configuration 7] 6. The control device for a multilevel inverter according to any one of configurations 1, 2, 4, and 5, wherein, when it is determined that the supplyable current value is less than the required current value in a case where the rotor (11) of the rotating electric machine is maintained in a rotation stopped state, the control unit controls the switch so that a d-axis current flows through the armature winding while a q-axis current flowing through the armature winding is set to 0 or a value close to 0. [Configuration 8] The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), The switch may be: Upper arm switches (SUH to SWH) and lower arm switches (SUL to SWL) connected in series; a clamp switch (QU to QW) for switching between conduction and interruption of a current flowing between a neutral point between the negative electrode side of the first capacitor and the positive electrode side of the second capacitor and the armature winding, the clamp switches being equal to the number of phases; the control device controls the switch to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor; the target capacitor is the second capacitor, The control device for a multilevel inverter according to configuration 7, wherein the control unit turns on the clamp switch in a specific phase determined according to the electrical angle of the rotating electric machine, turns off the lower arm switches in each phase, and turns on and off the upper arm switches in phases other than the specific phase among the phases, thereby causing a d-axis current to flow through the armature winding. [Configuration 9] The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), The switch may be: Upper arm switches (SUH to SWH) and lower arm switches (SUL to SWL) connected in series; a clamp switch (QU to QW) for switching between conduction and interruption of a current flowing between a neutral point between the negative electrode side of the first capacitor and the positive electrode side of the second capacitor and the armature winding, the clamp switches being equal to the number of phases; the control device controls the switch to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor; the target capacitor is the first capacitor, The control device for a multilevel inverter according to configuration 7, wherein the control unit turns on the clamp switch in a specific phase determined according to the electrical angle of the rotating electric machine, turns off upper arm switches in each phase, and turns on and off lower arm switches in phases other than the specific phase among the phases, thereby causing a d-axis current to flow through the armature winding. [Explanation of symbols]

[0099] 10... rotating electric machine, 13U to 13W... U to W phase windings, 20... storage battery, 21, 22... first and second capacitors, 30... inverter, 40... DC-DC converter, 41... electric compressor, 50... control device, SUH to SWH... U to W phase upper arm switches, SUL to SWL... U to W phase lower arm switches, QU to QW... U to W phase clamp switches.

Claims

1. a plurality of capacitors (21, 22, 71 to 74) connected in series; The present invention is applied to a multilevel inverter (30, 70) including switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and an armature winding (13U to 13W) of a rotating electric machine (10), A control device (50) for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), An electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, a determination unit that determines whether a current value that can be supplied to the electrical device is less than a current value required by the electrical device; a control unit that, when it is determined that the supplyable current value is less than the required current value, controls the switch so that the current flowing through the armature winding is larger than that when it is determined that the supplyable current value is equal to or greater than the required current value.

2. 2. The control device for a multilevel inverter according to claim 1, wherein the control unit controls the switch so that the larger the required current value, the larger the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding.

3. a plurality of capacitors (21, 22, 71 to 74) connected in series; The present invention is applied to a multilevel inverter (30, 70) including switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and an armature winding (13U to 13W) of a rotating electric machine (10), A control device (50) for a multilevel inverter that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), An electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, A control device for a multilevel inverter, comprising: a control unit that controls the switch so that the greater the required current value of the electrical device, the greater the current value supplied from the power source to the target capacitor via the multilevel inverter and the armature winding.

4. 3. The control device for a multilevel inverter according to claim 1, wherein, when it is determined that the supplyable current value is less than the required current value, the control unit controls the switch so that a d-axis current value to be passed through the armature winding is larger than when it is determined that the supplyable current value is equal to or greater than the required current value.

5. 5. The control device for a multilevel inverter according to claim 4, wherein, when it is determined that the supplyable current value is less than the required current value, the control unit controls the switch to increase the d-axis current value, and controls the switch so that an operating point determined by the d- and q-axis currents flowing through the armature winding is on an equal torque curve of the rotating electric machine when it is determined that the supplyable current value is equal to or greater than the required current value.

6. The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), a three-level inverter including, as the switches, switches (SUH to SWL, QU to QW, Su1 to Sw4) that electrically connect the armature winding to any one of the positive side of the first capacitor, a neutral point between the negative side of the first capacitor and the positive side of the second capacitor, and the negative side of the second capacitor; The multilevel inverter control device according to any one of claims 1 to 3, wherein the switch is controlled to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor.

7. 3. The control device for a multilevel inverter according to claim 1, wherein when it is determined that the supplyable current value is less than the required current value in a case where the rotor (11) of the rotating electric machine is maintained in a rotation stopped state, the control unit controls the switch so that a d-axis current flows through the armature winding while a q-axis current flowing through the armature winding is set to 0 or a value close to 0.

8. The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), The switch may be: upper arm switches (SUH to SWH) and lower arm switches (SUL to SWL) connected in series; and clamp switches (QU to QW) for switching between conduction and interruption of a current flowing between a neutral point between the negative electrode side of the first capacitor and the positive electrode side of the second capacitor and the armature winding, the number of which corresponds to the number of phases; the control device controls the switch to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor; the target capacitor is the second capacitor, 8. The control device for a multilevel inverter according to claim 7, wherein the control unit turns on the clamp switch in a specific phase determined according to an electrical angle of the rotating electric machine, turns off lower arm switches in each phase, and turns on and off upper arm switches in phases other than the specific phase among the phases, thereby causing a d-axis current to flow through the armature winding.

9. The multilevel inverter comprises: The capacitors include a first capacitor (21) and a second capacitor (22), The switch may be: upper arm switches (SUH to SWH) and lower arm switches (SUL to SWL) connected in series; and clamp switches (QU to QW) for switching between conduction and interruption of a current flowing between a neutral point between the negative electrode side of the first capacitor and the positive electrode side of the second capacitor and the armature winding, the number of which corresponds to the number of phases; the control device controls the switch to output one of three voltages that can be output from the series connection of the first capacitor and the second capacitor; the target capacitor is the first capacitor, 8. The control device for a multilevel inverter according to claim 7, wherein the control unit turns on the clamp switch in a specific phase determined according to an electrical angle of the rotating electric machine, turns off upper arm switches in each phase, and turns on and off lower arm switches in phases other than the specific phase among the phases, thereby causing a d-axis current to flow through the armature winding.

10. a plurality of capacitors (21, 22, 71 to 74) connected in series; switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and the armature windings (13U to 13W) of the rotating electric machine (10); A computer (50) and a multilevel inverter (30, 70) including: a program for causing the computer to execute a process of controlling the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), An electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, a determining step of determining whether or not a supplyable current value to the electrical device is less than a required current value of the electrical device; a control step of controlling the switch so that, when it is determined that the supplyable current value is less than the required current value, the current flowing through the armature winding is larger than that when it is determined that the supplyable current value is equal to or greater than the required current value.

11. a plurality of capacitors (21, 22, 71 to 74) connected in series; switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and the armature windings (13U to 13W) of the rotating electric machine (10); a control device (50) that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), An electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, The control device a determination unit that determines whether a current value that can be supplied to the electrical device is less than a current value required by the electrical device; a control unit that, when it is determined that the supplyable current value is less than the required current value, controls the switch so that the current flowing through the armature winding is larger than that when it is determined that the supplyable current value is equal to or greater than the required current value.

12. a plurality of capacitors (21, 22, 71 to 74) connected in series; switches (SUH to SWL, QU to QW, Su1 to Sw4, S1 to S8) electrically connected to the capacitor and the armature windings (13U to 13W) of the rotating electric machine (10); a control device (50) that controls the switch so as to output one of a plurality of voltages that can be output from a series connection of a plurality of the capacitors, The plurality of series-connected capacitors can be connected in parallel to a power source (20), An electric device (40, 41) can be connected in parallel to a target capacitor that is a part of the plurality of capacitors, The control device is a multilevel inverter having a control unit that controls the switch so that the value of the current supplied from the power source to the target capacitor via the multilevel inverter and the armature winding increases as the required current value of the electrical equipment increases.

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