CN117546404A - Control device and program for system - Google Patents

Abstract

A control device is applied to a system including a rotating electrical machine (20) having a rotor (22) and a stator winding (21), an electric storage unit (31), and an inverter (30) having an upper arm Switch (SWH) and a lower arm Switch (SWH). The control device comprises: a command calculation unit (55) that calculates a command value that is either a command torque (Trq) or a command rotational speed (Nm) of the rotating electrical machine; and a rotating electrical machine control unit (37) that performs switching control of the upper arm switch and the lower arm switch based on the calculated command value, so as to control the torque of the rotating electrical machine to the command torque. The rotating electric machine control unit calculates an upper limit rotation speed (Nmlim) of the rotor that does not overheat the rotating electric machine and the inverter, based on the driving state of the system. The command calculation unit performs a protection process for setting the rotation speed of the rotor to the calculated upper limit rotation speed or less.

Description

Control device and program for system

Citation of related application

The present application is based on Japanese patent application No. 2021-105121 filed on 24, 6, 2021, the contents of which are incorporated herein by reference.

Technical Field

The present disclosure relates to a control device and a program of a system.

Background

As such a control device, as described in patent document 1, a control device suitable for a system including a rotating electrical machine and an inverter is known. The control device calculates a command torque of the rotating electrical machine, and performs switching control of an upper arm switch and a lower arm switch constituting the inverter to control the torque of the rotating electrical machine to the calculated command torque.

In order to prevent the rotating electric machine and the inverter from being overheated, the control device increases the amount of decrease in the command torque for torque control with respect to the calculated command torque as the temperature of the rotating electric machine increases when the temperature of the rotating electric machine exceeds a predetermined temperature. By performing torque limitation in this way, overheat protection of the rotating electrical machine is achieved.

Prior art literature

Patent literature

Patent document 1: japanese patent laid-open No. 2008-260428

Disclosure of Invention

Depending on the driving state of the system including the rotating electrical machine and the inverter, overheat protection of the rotating electrical machine and the inverter may not be performed even if torque limitation is performed.

A main object of the present disclosure is to provide a control device and a program of a system capable of suppressing a rotating electrical machine and an inverter from becoming overheated.

The present disclosure is a control device of a system, the control device of the system being adapted for use in a system comprising:

a rotating electrical machine having a rotor and a stator winding;

an electric storage unit;

an inverter that has an upper arm switch and a lower arm switch and that electrically connects the stator winding and the power storage unit, wherein the control device of the system includes:

a command calculation unit configured to calculate a command value that is either a command torque or a command rotational speed of the rotating electrical machine; and

a rotating electrical machine control unit that performs switching control of the upper arm switch and the lower arm switch based on the calculated command value to control torque of the rotating electrical machine to the command torque,

the rotating electric machine control unit calculates an upper limit rotation speed of the rotor at which the rotating electric machine and the inverter are not overheated based on a driving state of the system,

the calculated upper limit rotation speed is sent to the upper control unit,

the command calculation unit performs a protection process for setting the rotation speed of the rotor to be equal to or lower than the received upper limit rotation speed.

As a case where overheat protection of the system is not possible even if torque limitation of the rotating electrical machine is performed, there is a case where the rotation speed of the rotor is high. Here, the rotational speed of the rotor in which at least one of the rotating electric machine and the inverter is in an overheated state varies according to the driving state of the system.

Accordingly, the rotating electrical machine control unit of the present disclosure calculates the upper limit rotation speed of the rotor that does not cause the rotating electrical machine and the inverter to be in an overheated state, based on the driving state of the system. The command calculation unit performs a protection process in which the rotational speed of the rotor is equal to or lower than the calculated upper limit rotational speed. This can suppress the overheat state of the rotating electrical machine and the inverter.

Drawings

The above objects, other objects, features and advantages of the present disclosure will become more apparent by reference to the accompanying drawings and the following detailed description. The drawings are as follows.

Fig. 1 is an overall configuration diagram of a system of a first embodiment.

Fig. 2 is a flowchart showing steps of the overheat protection process performed by the MGCU.

Fig. 3 is a diagram showing a change in the operation region of the rotating electrical machine according to a change in the power supply voltage.

Fig. 4 is a diagram showing a change in the operation region of the rotating electrical machine accompanying gradual degradation of the battery.

Fig. 5 is a diagram showing a change in the operation region of the rotating electrical machine according to a change in the carrier frequency.

Fig. 6 is a diagram showing a change in the operation region of the rotary electric machine accompanying a change in dead time.

Fig. 7 is a diagram showing a change in the operation region of the rotating electrical machine according to a change in the cooling water temperature.

Fig. 8 is a diagram showing a change in the operation region of the rotating electrical machine accompanying a change in the magnet temperature.

Fig. 9 is a graph showing a relationship between a motor temperature and a first coefficient.

Fig. 10 is a diagram showing a relationship between the inverter temperature and the second coefficient.

Fig. 11 is a flowchart showing steps of the overheat protection process performed by the EVCU.

Fig. 12 is a flowchart showing steps of the overheat protection process performed by the EVCU.

Fig. 13 is a flowchart showing steps of the overheat protection process performed by the MGCU of the second embodiment.

Fig. 14 is a flowchart showing steps of the overheat protection process performed by the MGCU of the third embodiment.

Detailed Description

< first embodiment >, first embodiment

Next, a first embodiment in which the control device of the present disclosure is mounted to an electric vehicle will be described with reference to the accompanying drawings.

As shown in fig. 1, the vehicle 10 includes a rotating electrical machine 20. The rotary electric machine 20 is a three-phase synchronous machine including stator windings 21 of respective phases of star connection. The stator windings 21 of the respective phases are arranged so as to be shifted by 120 ° in electrical angle. The rotating electrical machine 20 of the present embodiment is a permanent magnet synchronous machine including permanent magnets (corresponding to "excitation poles") in the rotor 22.

The rotating electrical machine 20 is an on-vehicle main unit, and the rotor 22 is capable of transmitting power to the drive wheels 11 of the vehicle 10. Torque generated by the rotating electric machine 20 functioning as a motor is transmitted from the rotor 22 to the driving wheel 11. Thereby, the driving wheel 11 is rotationally driven.

The rotating electrical machine 20 of the present embodiment is an in-wheel motor integrally provided to a wheel of the vehicle 10. No transmission is provided in the power transmission path between the rotor 22 and the drive wheel 11, and the rotor 22 is fixed with respect to the rim of the drive wheel 11. Therefore, the rotational speed [ rpm ] of the rotor 22 is the same as the rotational speed [ rpm ] of the driving wheel 11. In the case where the vehicle 10 includes left and right front wheels and left and right rear wheels, in-wheel motor units are provided for the four wheels, respectively, or in-wheel motors are provided for the respective front wheels or the respective rear wheels. An inverter 30 described later is provided separately for the rotating electrical machines 20 of the drive wheels 11. In addition, the number of wheels is not limited to four.

The vehicle 10 includes an inverter 30, a capacitor 31 (corresponding to a "power storage unit"), and a battery 40. The inverter 30 includes a series connection of an upper arm switch SWH and a lower arm switch SWL corresponding to three phases. In the present embodiment, each of the switches SWH and SWL is a voltage-controlled semiconductor switching element, specifically, an IGBT. Therefore, the high-potential side terminal of each switch SWH, SWL is a collector, and the low-potential side terminal is an emitter. The switches SWH and SWL are connected in anti-parallel with the flywheel diodes DH and DL.

In each phase, a first end of the stator winding 21 is connected to an emitter of the upper arm switch SWH and a collector of the lower arm switch SWL. The second ends of the stator windings 21 of the phases are connected to each other at a neutral point. In the present embodiment, the number of turns of the stator winding 21 of each phase is set to be the same.

The collector of upper arm switch SWH of each phase and the positive terminal of battery 40 are connected by positive electrode side bus bar Lp. The emitter of the lower arm switch SWL of each phase and the negative terminal of the battery 40 are connected by a negative electrode side bus line Ln. The positive electrode-side bus bar Lp and the negative electrode-side bus bar Ln are connected by a capacitor 31. The capacitor 31 may be built in the inverter 30 or may be provided outside the inverter 30.

The battery 40 is, for example, a battery pack, and the terminal voltage of the battery 40 is, for example, several hundred V. The battery 40 is, for example, a secondary battery such as a lithium ion battery or a nickel hydrogen battery.

The vehicle 10 includes a current sensor 32, a voltage sensor 33, a rotation angle sensor 34, a motor temperature sensor 35, an inverter temperature sensor 36, and an MGCU 37 (electric motor control unit (Motor Generator Control Unit), which corresponds to a "rotating electric machine control unit"). The current sensor 32 detects the current flowing through the stator winding 21 of at least two of the respective phases. The voltage sensor 33 detects the terminal voltage of the capacitor 31 as the power supply voltage Vdc. The rotation angle sensor 34 is, for example, an resolver, and detects the rotation angle (electrical angle) of the rotor 22. The motor temperature sensor 35 detects the temperature of the rotating electrical machine 20 as a motor temperature Tmgd. In the present embodiment, the motor temperature sensor 35 detects the temperature of the stator winding 21 as the motor temperature Tmgd. The motor temperature sensor 35 is, for example, a thermistor. The inverter temperature sensor 36 detects the temperature of the inverter 30 as an inverter temperature Tinvd. The inverter temperature sensor 36 is, for example, a temperature sensing diode or a thermistor. The temperature of the inverter 30 is, for example, the temperatures of the upper arm switch SWH and the lower arm switch SWL. The detection values of the sensors 32 to 36 are input to the MGCU 37.

In addition, the detection value of the voltage sensor 33 is actually input to the MGCU 37 via the battery CU included in the vehicle 10. However, since it is not critical that the vehicle 10 includes the MGCU 37, the EVCU 55, and the CUs other than the brake CU 62 in the on-vehicle CUs and the like, the battery CU and the like are not illustrated in fig. 1.

The MGCU 37 is mainly composed of a microcomputer 37a (corresponding to "first computer"), and the microcomputer 37a includes a CPU. The functions provided by the microcomputer 37a can be provided by software recorded in the physical memory means and a computer executing the software, only hardware, or a combination thereof. For example, in the case where the microcomputer 37a is provided by an electronic circuit as hardware, it can be provided by a digital circuit or an analog circuit including a plurality of logic circuits. For example, the microcomputer 37a executes a program stored in a non-transitory physical storage medium (non-transitory tangible storage medium) included as a storage section. The program includes, for example, a program of the processing shown in fig. 2 and the like. The method corresponding to the program is executed by executing the program. The storage unit is, for example, a nonvolatile memory. The program stored in the storage unit is updated, for example, via a network such as the internet.

The MGCU 37 receives a command torque Trq transmitted from an EVCU 55 (Electric Vehicle Control Unit: electric vehicle control unit) described later. MGCU 37 performs switching control of each of switches SWH and SWL constituting inverter 30 to control the torque of rotary electric machine 20 to the received command torque Trq. In each phase, the upper arm switch SWH and the lower arm switch SWL are alternately turned on while sandwiching the dead time.

The MGCU 37 performs power running drive control. The powering drive control is a switching control of the inverter 30 for converting the dc power output from the battery 40 into ac power and supplying the ac power to the stator winding 21. In this control, the rotating electrical machine 20 functions as an electric motor, and generates a power running torque. The MGCU 37 performs regenerative drive control. The regenerative drive control is a switching control of the inverter 30 for converting ac power generated by the rotating electric machine 20 into dc power and supplying the dc power to the battery 40. In this control, the rotating electrical machine 20 functions as a generator, and generates regenerative torque.

The vehicle 10 includes: a circulation path 50 through which cooling water circulates; and an electric water pump 51, a radiator 52, and an electric fan 53 as cooling devices. The cooling water is circulated by driving the water pump 51 by supplying power. In the circulation path 50, the inverter 30 and the rotating electric machine 20 are disposed in this order on the downstream side of the water pump 51. However, the order of arrangement of the rotating electrical machine 20 and the inverter 30 in the circulation path 50 is not limited to the above.

A radiator 52 is provided between the inverter 30 and the water pump 51 in the circulation path 50. The radiator 52 cools the cooling water flowing in through the circulation path 50 and supplies the cooling water to the water pump 51. The cooling water flowing into the radiator 52 is cooled by the running wind that is blown toward the radiator 52 along with the running of the vehicle 10 and the wind that is blown toward the radiator 52 by the rotation of the drive fan 53.

The vehicle 10 includes a cooling water temperature sensor 54 and an EVCU 55 (corresponding to a "command calculation portion"). The cooling water temperature sensor 54 detects the temperature of the cooling water flowing to the inverter 30 in the circulation path 50.

The EVCU 55 is mainly composed of a microcomputer 55a (corresponding to "second computer"), and the microcomputer 55a includes a CPU. In the present embodiment, the EVCU 55 corresponds to a host control unit of the MGCU 37 and a brake CU 62 described later. The functions provided by the microcomputer 55a can be provided by software recorded in the physical memory means and a computer executing the software, only hardware, or a combination thereof. For example, in the case where the microcomputer 55a is provided by an electronic circuit as hardware, it can be provided by a digital circuit or an analog circuit including a plurality of logic circuits. For example, the microcomputer 55a executes a program stored in a storage section included in itself. The program includes, for example, the process of driving the cooling device, and the process shown in fig. 11 and 12. The method corresponding to the program is executed by executing the program. The program stored in the storage unit is updated, for example, via a network such as the internet.

The vehicle 10 includes a brake device 60, a brake sensor 61, and a brake CU 62. The brake device 60 generates braking force by applying friction to wheels including the driving wheels 11. The brake device 60 includes a master cylinder and a brake pad that operate according to the amount of depression of a brake pedal. The brake sensor 61 detects a brake stroke, which is a depression amount of a brake pedal of a brake operation member of a driver. The detection value of the brake sensor 61 is input to the brake CU 62.

The brake CU 62 is mainly composed of a microcomputer 62a, and the microcomputer 62a includes a CPU. The functions provided by the microcomputer 62a can be provided by software recorded in the physical memory means and a computer executing the software, only hardware, or a combination thereof. For example, in the case where the microcomputer 62a is provided by an electronic circuit as hardware, it can be provided by a digital circuit or an analog circuit including a plurality of logic circuits. For example, the microcomputer 62a executes a program stored in a storage section included in itself. The program includes, for example, a program such as a braking force control process of the brake device 60. The method corresponding to the program is executed by executing the program. The program stored in the storage unit is updated, for example, via a network such as the internet.

The MGCU 36, the EVCU 55, and the brake CU 62 CAN exchange information with each other through a prescribed communication form (e.g., CAN).

The vehicle 10 includes a throttle sensor 70 and a steering angle sensor 71. The accelerator sensor 70 detects an accelerator stroke, which is a depression amount of an accelerator pedal that is an accelerator operation member of the driver. The steering angle sensor 71 detects a steering angle accompanying the operation of the steering wheel by the driver. The detection values of the accelerator sensor 70 and the steering angle sensor 71 are input to the EVCU 55. The EVCU 55 calculates a command rotation speed Nm of the rotor 22 based on the accelerator stroke detected by the accelerator sensor 70 and the steering angle detected by the steering angle sensor 71. The EVCU 55 calculates the command torque Trq as an operation amount for feedback-controlling the rotational speed of the rotor 22 to the calculated command rotational speed Nm. The EVCU 55 transmits the calculated command torque Trq (corresponding to the "command value") to the MGCU 36. The rotation speed of the rotor 22 may be calculated based on the detection value of the rotation angle sensor 34, for example. In addition, in the case where the vehicle 10 includes an autopilot function, the EVCU 55 may calculate the command rotation speed Nm when executing the autopilot mode, for example, based on the target travel speed of the vehicle 10 set by the autopilot CU included in the vehicle 10.

The brake CU 62 calculates the total braking torque Fbrk to be applied to the wheels based on the braking stroke detected by the brake sensor 61. The brake CU 62 receives the regenerative braking torque Fgmax from the EVCU 55. The regenerative braking torque Fgmax is the maximum value of the current state of the braking torque that can be applied to the wheels by the regenerative drive control.

The brake CU 62 calculates a regenerative requested braking torque Fgb and a mechanical requested braking torque Fmb based on the regenerative braking torque Fgmax and the total braking torque Fbrk. For example, the brake CU 62 calculates the mechanical requested braking torque Fmb by subtracting the regenerative requested braking torque Fgb from the total braking torque Fbrk.

The brake CU 62 transmits the calculated regenerative request brake torque Fgb to the EVCU 55. The EVCU 55 transmits the received regenerative request braking torque Fgb as the command torque Trq to the MGCU 37. The larger the regenerative request braking torque Fgb is, the larger the generated electric power is supplied from the rotating electric machine 20 to the battery 40 via the inverter 30.

In addition, the brake CU 62 transmits the calculated mechanical requested braking torque Fmb to the brake device 60. Thereby, the braking torque applied to the wheels by the brake device 60 is controlled to the mechanically requested braking torque Fmb.

Next, overheat protection control performed by the EVCU 55 and the MGCU 37 will be described.

First, overheat protection control performed by the MGCU 37 will be described with reference to fig. 2. The process shown in fig. 2 is repeatedly executed at a predetermined control cycle, for example.

In step S10, the current rotation speed Nmc of the rotor 22 is acquired. The rotation speed Nmc may be, for example, a rotation speed of the rotor 22 calculated based on a detection value of the rotation angle sensor 34. Note that, when the command rotation speed Nm is transmitted from the EVCU 55, the rotation speed Nmc may be the command rotation speed Nm.

In step S11, the power supply voltage Vdc detected by the voltage sensor 33, the control state of the inverter 30, the cooling water temperature WTd detected by the cooling water temperature sensor 54, and the temperature of the permanent magnet of the rotor 22 (hereinafter, the magnet temperature tΦd) are acquired. Here, for example, the motor temperature Tmgd detected by the motor temperature sensor 35 may be used as the magnet temperature tΦd, or the magnet temperature tΦd estimated based on the motor temperature Tmgd may be used.

The control states of the inverter 30 include carrier frequency, dead time, control mode, and modulation mode. The control modes include PWM control, overmodulation control and rectangular wave control.

The PWM control is a switching control for switching the upper arm switch SWH and the lower arm switch SWL, which are used to make the respective phase voltages applied to the stator winding 21 have PWM voltage waveforms, when the peak value of the respective phase voltages applied to the stator winding 21 is equal to or lower than the terminal voltage of the battery 40. Specifically, the PWM control is a switching control based on a comparison between the command voltage of each phase and the magnitude of the carrier signal. The modulation scheme of PWM control includes three-phase modulation or two-phase modulation.

The overmodulation control is switching control of the upper arm switch SWH and the lower arm switch SWL for making each phase voltage applied to the stator winding 21 have a PWM voltage waveform higher in modulation ratio than the PWM voltage waveform realized by the PWM control when the peak value of each phase voltage applied to the stator winding 21 exceeds the terminal voltage of the battery 40. The rectangular wave control is a switching control that turns on each of the upper arm switch SWH and the lower arm switch SWL once while sandwiching the dead time in one electrical angle period.

In step S12, an upper limit value of torque (hereinafter, possible torque Trqpb) that can be generated by the rotating electrical machine 20 is calculated based on the parameters acquired in step S11.

First, a method of calculating the possible torque Trqpb based on the power supply voltage Vdc will be described with reference to fig. 3. Fig. 3 shows an operation region of the operation point determined by the torque Trq and the rotation speed Nm. The action region includes a first region RA and a second region RB. The first region RA is a region in which field weakening control for causing field weakening current to flow through the stator winding 21 is not performed. The second region RB is a region in which field weakening control is performed, and is a region adjacent to the first region RA and on the high-speed side with respect to the first region RA. The boundary on the higher rotational speed side of the second region RB is the maximum value of the rotational speed Nm (hereinafter, the highest rotational speed Nmax).

When the torque Trq is a positive value, the power running drive control is performed. On the other hand, when the torque Trq is negative, the regenerative drive control is performed.

The boundary on the high torque side that defines the region in which the power running drive control is performed in the operation region is the power running torque TmC, and the boundary on the high torque side that defines the region in which the regenerative drive control is performed is the regenerative torque TgC.

The rotational speed defining the boundary between the first region RA and the second region RB is a speed threshold Nth. The MGCU 37 determines that the current operation point is in the first region RA when determining that the rotational speed Nmc is equal to or less than the speed threshold Nth, and determines that the current operation point is in the second region RB when determining that the rotational speed Nmc exceeds the speed threshold Nth.

Fig. 3 shows a case where the power supply voltage Vdc is the first voltage VB1 and a case where the power supply voltage Vdc is the second voltage VB2 (> VB 1). In fig. 3, RA (VB 1) represents a first region RA when the power supply voltage Vdc is the first voltage VB1, and RA (VB 2) represents a first region RA when the power supply voltage Vdc is the second voltage VB 2. The same is true for the second region RB, the speed threshold Nth, the power running torque TmC, the regenerative torque TgC, and the highest rotational speed Nmax.

As shown in fig. 3, the higher the power supply voltage Vdc is, the wider the operation region is. Therefore, the higher the power supply voltage Vdc, the larger the possible torque Trqpb corresponding to the current rotation speed Nmc. Specifically, the higher the power supply voltage Vdc, the larger the power running torque TmC corresponding to the current rotation speed Nmc, and the larger the absolute value of the regenerative torque TgC corresponding to the current rotation speed Nmc.

Incidentally, as shown in fig. 4, the operation region may be narrowed as the degradation degree of the battery 40 is increased. That is, the greater the degree of degradation, the smaller the power running torque TmC and the smaller the absolute value of the regenerative torque TgC may be.

Next, a method of calculating the possible torque Trqpb based on the frequency of the carrier signal (hereinafter, carrier frequency) when the control scheme is PWM control will be described with reference to fig. 5. Fig. 5 shows a case where the carrier frequency is the first frequency FC1 and a case where the carrier frequency is the second frequency FC2 (< FC 1). In fig. 5, RA (FC 1) represents a first region RA when the carrier frequency is the first frequency FC1, and RA (FC 2) represents a first region RA when the carrier frequency is the second frequency FC 2. The same is true for the second region RB, the speed threshold Nth, the power running torque TmC, the regenerative torque TgC, and the highest rotational speed Nmax.

As shown in fig. 5, the lower the carrier frequency is, the higher the voltage utilization ratio is, and thus the operation region is widened. Therefore, the lower the carrier frequency, the larger the possible torque Trqpb corresponding to the current rotation speed Nmc. Specifically, the lower the carrier frequency, the larger the power running torque TmC corresponding to the current rotation speed Nmc, and the larger the absolute value of the regenerative torque TgC corresponding to the current rotation speed Nmc.

Next, a method of calculating the possible torque Trqpb based on the dead time will be described with reference to fig. 6. Fig. 6 shows a case where the dead time is the first time DT1 and a case where the dead time is the second time DT2 (< DT 1). In fig. 6, RA (DT 1) represents a first region RA when the dead time is a first time DT1, and RA (DT 2) represents a first region RA when the dead time is a second time DT 2. The same is true for the second region RB, the speed threshold Nth, the power running torque TmC, the regenerative torque TgC, and the highest rotational speed Nmax.

As shown in fig. 6, the shorter the dead time is, the higher the voltage utilization ratio is, and thus the operation region is enlarged. Therefore, the shorter the dead time, the larger the possible torque Trqpb. In detail, the shorter the dead time, the larger the power running torque TmC corresponding to the current rotation speed Nmc, and the larger the absolute value of the regenerative torque TgC corresponding to the current rotation speed Nmc.

Further, the power running torque TmC and the regenerative torque TgC may be calculated based on which of PWM control, overmodulation control, or rectangular wave control the control method is. Further, the power running torque TmC and the regenerative torque TgC may be calculated based on which of two-phase modulation and three-phase modulation the modulation scheme is.

Next, using fig. 7, a method of calculating the possible torque Trqpb based on the cooling water temperature WTd is used. Fig. 7 shows a case where the cooling water temperature WTd is the first water temperature WT1 and a case where the cooling water temperature WTd is the second water temperature WT2 (< WT 1). In fig. 7, the speed threshold Nth is not illustrated. In fig. 7, ra+rb (WT 1) represents an operation region when the cooling water temperature WTd is the first water temperature WT1, and ra+rb (WT 2) represents an operation region when the cooling water temperature WTd is the second water temperature WT 2. The same applies to the power running torque TmC, the regenerative torque TgC, and the highest rotational speed Nmax.

As shown in fig. 7, the operation region increases as the cooling water temperature WTd decreases. Therefore, the lower the cooling water temperature WTd, the greater the possible torque Trqpb corresponding to the current rotation speed Nmc. Specifically, the lower the cooling water temperature WTd, the larger the power running torque TmC corresponding to the current rotation speed Nmc, and the larger the absolute value of the regenerative torque TgC corresponding to the current rotation speed Nmc.

Next, a method of calculating the possible torque Trqpb based on the magnet temperature tΦd will be described with reference to fig. 8. Fig. 8 shows the case where the magnet temperature tΦd is the first temperature tΦ1 to the third temperature tΦ3 (tΦ1 < tΦ2 < tΦ3). In fig. 8, the speed threshold Nth and the operation area on the reproduction side are not shown. In fig. 8, ra+rb (tΦ1) represents an operation region when the magnet temperature tΦd is the first temperature tΦ1, ra+rb (tΦ2) represents an operation region when the magnet temperature tΦd is the second temperature tΦ2, and ra+rb (tΦ3) represents an operation region when the magnet temperature tΦd is the third temperature tΦ3. The same is true for the power running torque TmC and the highest rotation speed Nmax.

As shown in fig. 8, since the higher the magnet temperature tΦd, the lower the magnetic flux of the permanent magnet, the smaller the possible torque Trqpb corresponding to the current rotation speed Nmc. In detail, the higher the magnet temperature tΦd, the smaller the power running torque TmC corresponding to the current rotation speed Nmc, and the smaller the absolute value of the regenerative torque TgC corresponding to the current rotation speed Nmc.

In addition, the possible torque Trqpb may be calculated based on, for example, map information or equation information that correlates the respective parameters acquired in step S11 with the possible torque Trqpb.

Returning to the explanation of fig. 2, next, in step S13, the motor temperature Tmgd detected by the motor temperature sensor 35 and the inverter temperature Tinvd detected by the inverter temperature sensor 36 are acquired.

In step S14, the upper limit torque Trqlim of the rotating electrical machine 20 is calculated based on the calculated possible torque Trqpb. First, the power running side will be described, and the product value of the power running torque TmC and the first coefficient Kmg and the product value of the power running torque TmC and the second coefficient Kinv will be calculated. As shown in fig. 9, the first coefficient Kmg is a value of 1 or less. In the present embodiment, when the motor temperature Tmgd is equal to or lower than the first motor temperature Tm1, the first coefficient Kmg is a first predetermined value KH (< 1). When the motor temperature Tmgd is higher than the first motor temperature Tm1 and smaller than the second motor temperature Tm2 (> Tm 1), the higher the motor temperature Tmgd is, the smaller the first coefficient Kmg is. When the motor temperature Tmgd is equal to or higher than the second motor temperature Tm2, the first coefficient Kmg becomes a second predetermined value KL (< KH) greater than 0.

As shown in fig. 10, the second coefficient Kinv is a value of 1 or less. In fig. 10 and 9, LL denotes a common horizontal axis scale. In the present embodiment, when the inverter temperature Tinvd is equal to or lower than the first inverter temperature Ti1, the second coefficient Kinv is the first predetermined value KH. In the case where the inverter temperature Tinvd is higher than the first inverter temperature Ti1 and smaller than the second inverter temperature Ti2 (> Ti 1), the higher the inverter temperature Tinvd is, the smaller the second coefficient Kinv is. When the inverter temperature Tinvd is equal to or higher than the second inverter temperature Ti2, the second coefficient Kinv becomes the second predetermined value KL. In the present embodiment, the first inverter temperature Ti1 is higher than the first motor temperature Tm1, and the second inverter temperature Ti2 is higher than the second motor temperature Tm 2.

The first coefficient Kmg when the motor temperature Tmgd is equal to or lower than the first motor temperature Tm1 and the second coefficient Kinv when the inverter temperature Tinvd is equal to or lower than the first inverter temperature Ti1 may be different values. The first coefficient Kmg when the motor temperature Tmgd is equal to or higher than the second motor temperature Tm2 and the second coefficient Kinv when the inverter temperature Tinvd is equal to or higher than the second inverter temperature Ti2 may be different values.

Then, the smaller of the calculated "tmc× Kmg" and "tmc×kinv" is set as the power running upper limit torque Trqmlim.

Next, the regenerative side will be described, and the product value of the regenerative torque TgC and the first coefficient Kmg and the product value of the regenerative torque TgC and the second coefficient Kinv are calculated. Then, the smaller of the absolute value of "TgC × Kmg" and the absolute value of "TgC ×kinv" is given a negative value and the regeneration upper limit torque Trqglim is given.

For example, when the torque of the rotating electric machine 20 is "tmc× Kmg" or "TgC × Kmg", the first coefficient Kmg may be set to a value that allows continuous driving of the rotating electric machine 20 without bringing the rotating electric machine into an overheated state. In the present embodiment, the overheat state of the rotating electrical machine 20 means that the temperature of the rotating electrical machine 20 (specifically, the stator winding 21) exceeds the allowable upper limit temperature of the rotating electrical machine 20 (specifically, the stator winding 21). For example, when the torque of the rotating electric machine 20 is "tmc×kinv" or "TgC ×kinv", the second coefficient Kinv may be set to a value that allows the inverter 30 to be continuously driven without being overheated. In the present embodiment, the inverter 30 being in the overheat state means that the temperature of the inverter 30 exceeds the allowable upper limit temperature of the inverter 30.

In step S15, the upper limit rotation speed Nmlim of the rotor 22 is calculated based on the parameters acquired in step S11. In the present embodiment, the upper limit rotation speed Nmlim is set as the speed threshold Nth. By this setting, the rotating electrical machine 20 and the inverter 30 do not become overheated. That is, the magnitude of the current vector flowing through the stator winding 21 to generate the predetermined torque is larger in the case of performing the field weakening control than in the case of not performing the field weakening control. Therefore, in order not to overheat the rotating electric machine 20 and the inverter 30, it is desirable to perform field weakening control as little as possible. Thereby, the upper limit rotation speed Nmlim is set as the speed threshold Nth.

First, a method of calculating the upper limit rotation speed Nmlim based on the power supply voltage Vdc will be described with reference to fig. 3. As shown in fig. 3, the higher the power supply voltage Vdc is, the larger the operation region is, and the higher the line of the speed threshold Nth is shifted. Therefore, the higher the power supply voltage Vdc, the higher the upper limit rotation speed Nmlim. In the present embodiment, the higher the power supply voltage Vdc, the higher the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC. The upper limit rotation speed Nmlim associated with the command torque Trq is information to be transmitted in step S16 described later.

Incidentally, as shown in fig. 4, in view of the fact that the greater the degree of deterioration of the battery 40, the smaller the operation region, the greater the degree of deterioration, the lower the upper limit rotation speed Nmlim may be.

Next, a method for calculating the upper limit rotation speed Nmlim based on the carrier frequency when the control method is PWM control will be described with reference to fig. 5. As shown in fig. 5, the lower the carrier frequency, the wider the operation region, and the higher the line of the speed threshold Nth is shifted. Therefore, the lower the carrier frequency, the higher the upper limit rotation speed Nmlim. In the present embodiment, the lower the carrier frequency, the higher the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC.

Next, a method of calculating the upper limit rotation speed Nmlim based on the dead time will be described with reference to fig. 6. As shown in fig. 6, the shorter the dead time, the wider the operation region, and the higher the line of the speed threshold Nth is shifted. Therefore, the shorter the dead time, the higher the upper limit rotation speed Nmlim. In the present embodiment, the shorter the dead time, the higher the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC.

The upper limit rotation speed Nmlim may be calculated based on which of PWM control, overmodulation control, and rectangular wave control the control method is. The upper limit rotation speed Nmlim may be calculated based on which of the two-phase modulation and the three-phase modulation the modulation scheme is.

Next, a method for calculating the upper limit rotation speed Nmlim based on the cooling water temperature WTd will be described. As shown in fig. 7, the lower the cooling water temperature WTd, the wider the operation region, and the higher the line of the speed threshold Nth is shifted. Therefore, the lower the cooling water temperature WTd, the higher the upper limit rotation speed Nmlim. In the present embodiment, the lower the cooling water temperature WTd, the higher the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC.

Next, a method for calculating the upper limit rotation speed Nmlim based on the magnet temperature T phid will be described. Since the magnetic flux of the permanent magnet is lower as the magnet temperature tΦd is higher, the line of the speed threshold Nth is shifted to the high-speed side. Therefore, the higher the magnet temperature tΦd, the higher the upper limit rotation speed Nmlim. In the present embodiment, the higher the magnet temperature tΦ, the higher the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC.

The upper limit rotation speed Nmlim may be calculated based on, for example, map information or equation information that correlates the respective parameters acquired in step S11 with the upper limit rotation speed Nmlim.

Returning to the explanation of fig. 2, in step S16, the power running upper limit torque Trqmlim and the regeneration upper limit torque Trqglim calculated in step S14 and the upper limit rotation speed Nmlim calculated in step S15 are transmitted to the EVCU 55. Specifically, the EVCU 55 is sent with information on each upper limit torque Trqmlim, trqglim associated with the current rotation speed Nmc and information on the upper limit rotation speed Nmlim associated with the command torque Trq from the power running torque TmC to the regenerative torque TgC.

Next, overheat protection control performed by the EVCU 55 will be described with reference to fig. 11 and 12. The processing shown in fig. 11 and 12 is repeatedly executed at a predetermined control cycle, for example. The control period of the EVCU 55 and the control period of the MGCU 37 may be the same or different.

First, the process of fig. 11 will be described. This process is a process of limiting the running speed of the vehicle 10.

In step S20, the current running speed Vs of the vehicle 10 is acquired. The travel speed Vs may be calculated based on the detection value of the rotation angle sensor 34, for example.

In step S21, the upper limit rotation speed Nmlim transmitted from the MGCU 37 is received.

In step S22, a running speed of the vehicle 10 (hereinafter, upper limit running speed Vlim) assuming that the rotation speed of the rotor 22 is the upper limit rotation speed Nmlim is calculated. For example, the upper limit running speed Vlim may be calculated using the following equation (eq 1). In the following formula (eq 1), RT represents the outer diameter of the wheel.

[ mathematics 1]

In order to receive information on the upper limit rotational speed Nmlim associated with the command torque Trq, an upper limit running speed Vlim associated with the command torque Trq is calculated.

In step S23, it is determined whether or not the current running speed Vs is equal to or lower than the upper limit running speed Vlim corresponding to the current command torque Trq. If a negative determination is made in step S23, a process is performed to reduce the running speed Vs of the vehicle 10 until the current running speed Vs becomes equal to or lower than the upper limit running speed Vlim.

The reason why the travel speed Vs is equal to or lower than the upper limit travel speed Vlim is described below. The magnitude of the current vector flowing through the stator winding 21 is larger when the field weakening control is performed than when the field weakening control is not performed. As a result, even if the command torque Trq is reduced to, for example, 0 when the operating point is located in the second region RB, the effective value of the phase current flowing through the stator winding 21 may not be equal to or less than the allowable upper limit current (specifically, the normal allowable current, for example) of the rotating electrical machine 20 (specifically, the stator winding 21).

In this case, the motor temperature Tmgd further increases to reach the off temperature Tshut, and the MGCU 37 performs off control to turn off all of the upper arm switch SWH and the lower arm switch SWL of each phase. However, in the second region RB, which is the high-speed side region, since the counter electromotive force induced in the stator winding 21 is high, the peak value of the line-to-line voltage of the stator winding 21 can exceed the terminal voltage of the capacitor 31. In this case, electric power regeneration is generated, and a current flows through a closed circuit including the stator winding 21, the diode DH of the upper arm switch SWH, the capacitor 31, and the diode DL of the lower arm switch SWL. As a result, the temperatures of the rotating electrical machine 20 and the inverter 30 further rise, and there is a possibility that the rotating electrical machine 20 and the inverter 30 may malfunction. Therefore, by reducing the running speed and reducing the rotational speed of the rotor 22, the counter electromotive force is reduced, and no electric power regeneration is generated. Thereby, the rotating electrical machine 20 and the inverter 30 are prevented from malfunctioning due to overheat abnormality.

In the present embodiment, the traveling speed may be reduced by implementing at least one of the following (a) and (B).

(A) The brake CU 62 is subjected to a process of giving an instruction to apply braking force to the wheels through the brake device 60.

According to the mechanical brake 60, it is not necessary to flow a current for generating regenerative torque through the stator winding 21. Therefore, the rotational speed of the rotor 22 and, in turn, the running speed is reduced while appropriately suppressing the temperature rise of the rotating electrical machine 20 and the inverter 30. Thereby, the operating point is shifted from the second region RB to the first region RA, the field weakening control is not performed, and the rotating electrical machine 20 and the inverter 30 are protected from overheating.

Further, according to the brake device 60, the rotational speed of the rotor 22 can be reduced and the running speed can be reduced irrespective of the switching control of the inverter 30. Therefore, for example, even in the case where the control of the inverter 30 is stopped, it is possible to reduce the rotation speed of the rotor 22 and reliably limit the current flowing through the stator winding 21, and to protect the rotating electrical machine 20 and the inverter 30 from overheating.

The process of applying braking force to the wheels by the brake device 60 is effective, for example, in the following cases. If the running road surface of the vehicle 10 is a downhill, the rotational speed of the rotor 22 may not be reduced even if the command torque Trq is reduced. In addition, when the SOC of the battery 40 is in a high SOC state higher than a predetermined amount, there is a possibility that the regenerative torque is limited or cannot be generated in order to prevent overcharge of the battery 40. In these cases, the process of applying braking force to the wheels by the brake device 60 is effective.

(B) The MGCU 37 is instructed to execute the regenerative drive control.

Specifically, this process is a process of setting the command torque Trq transmitted to the MGCU 37 to a negative value. In this case, the regenerative torque can be generated, and the running speed is reduced. Thereby, the operating point is shifted from the second region RB to the first region RA, and the rotating electrical machine 20 and the inverter 30 are protected from overheating. The regenerative drive control may be performed so that the effective value of the phase current flowing through the stator winding 21 is equal to or less than the allowable upper limit current (specifically, for example, the normal allowable current) of the rotating electric machine 20 (specifically, the stator winding 21).

In the case where the command rotation speed Nm is transmitted from the EVCU 55 to the MGCU 37, the EVCU 55 may perform a process of reducing the command rotation speed Nm transmitted to the MGCU 37.

By this process, the rotational speed of the rotor 22 decreases, and the running speed of the vehicle 10 decreases. Thereby, the operating point is shifted from the second region RB to the first region RA, and the rotating electrical machine 20 and the inverter 30 are protected from overheating. The command rotation speed Nm to be transmitted may be gradually reduced so that the deceleration of the vehicle 10 becomes equal to or smaller than the predetermined deceleration. The predetermined deceleration may be set to a value (for example, 0.2G) that can ensure safety of the occupant of the vehicle 10.

Next, the process of fig. 12 will be described. This process is a process of limiting torque.

In step S30, the upper limit torque Trqlim (specifically, the power running upper limit torque Trqmlim and the regeneration upper limit torque Trqglim) transmitted from the MGCU 37 is received.

In step S31, when the power running drive control is performed, it is determined whether or not the command torque Trq transmitted to the MGCU 37 is equal to or less than the power running upper limit torque Trqmlim. If it is determined that the command torque Trq exceeds the power running upper limit torque Trqmlim, the flow proceeds to step S32, where the command torque Trq sent to the MGCU 37 is reduced to the power running upper limit torque Trqmlim or less. Thereby, the rotating electrical machine 20 and the inverter 30 are protected from overheating.

On the other hand, in the case of performing the regenerative drive control, it is determined whether or not the absolute value of the command torque Trq transmitted to the MGCU 37 is equal to or less than the absolute value of the regenerative upper limit torque Trqglim. If it is determined that the absolute value of the command torque Trq exceeds the absolute value of the regeneration upper limit torque Trqglim, the flow proceeds to step S32, where the absolute value of the command torque Trq transmitted to the MGCU 37 is reduced to the absolute value of the regeneration upper limit torque Trqglim or less. Thereby, the rotating electrical machine 20 and the inverter 30 are protected from overheating.

In the present embodiment described above, MGCU 37 and EVCU 55 cooperate with each other to perform overheat protection of rotary electric machine 20 and inverter 30. Here, the MGCU 37 calculates the upper limit rotation speed Nmlim based on the power supply voltage Vdc, the cooling water temperature WTd, and other parameters. Therefore, the control of the rotating electric machine 20 can be continued without limiting the operation range of the operation point of the rotating electric machine 20 as much as possible. As a result, overheat protection of the rotating electrical machine 20 and the inverter 30 can be performed without limiting the driving force of the vehicle 10 as much as possible.

< modification of the first embodiment >

Communication between the CUs 37, 55, 62 via CAN or the like is accompanied by delay. Accordingly, the MGCU 37 may transmit the upper limit torque Trqlim and the upper limit rotation speed Nmlim corresponding to the operation point expected in the future to the EVCU 55 in consideration of the influence of the communication delay.

< second embodiment >

Hereinafter, a second embodiment will be described with reference to the drawings, focusing on differences from the first embodiment. In the present embodiment, the calculation method of the upper limit rotation speed Nmlim in the MGCU 37 is changed.

The overheat protection control performed by the MGCU 37 will be described with reference to fig. 13. The process shown in fig. 13 is repeatedly executed at a predetermined control cycle, for example.

In step S40, the upper limit rotation speed Nmlim is set to the rotation speed of the rotor 22 so that the peak value Vemf of the line-to-line voltage induced in the stator winding 21 with the rotation of the rotor 22 is the same as the power supply voltage Vdc detected by the voltage sensor 33. Since the line-to-line voltage depends on the rotation speed of the rotor 22, the upper limit rotation speed Nmlim may be calculated based on, for example, map information or equation information that correlates the rotation speed of the rotor 22, the power supply voltage Vdc, and the upper limit rotation speed Nmlim, the rotation speed, and the power supply voltage Vdc. The upper limit rotation speed Nmlim of the present embodiment is a value higher than the speed threshold Nth when the command torque Trq is 0.

In step S41, the upper limit rotation speed Nmlim calculated in step S40 is transmitted to the EVCU 55.

According to the present embodiment described above, even when the control of the inverter 30 is stopped, for example, the rotation speed of the rotor 22 can be reduced, the current flowing through the stator winding 21 can be reliably limited, and the rotating electric machine 20 and the inverter 30 can be protected from overheating.

< modification of the second embodiment >

In step S40, the rotation speed of the rotor 22, in which the peak value of the line-to-line voltage is the same as the power supply voltage Vdc when the magnet temperature T phid is the lower limit value of the value range of the magnet temperature T phid, may be calculated as the upper limit rotation speed Nmlim. In this case, it is assumed that the line-to-line voltage induced in the stator winding 21 becomes high and the upper limit rotation speed Nmlim is calculated. Therefore, even when the operating point temporarily fluctuates due to the temporal fluctuation of the power supply voltage Vdc or the rotational speed of the rotor 22, the operating point can be made to stay in the first region RA as much as possible.

< third embodiment >

The third embodiment will be described below with reference to the drawings, focusing on differences from the first embodiment. In the embodiment, the calculation method of the upper limit rotation speed Nmlim in the MGCU 37 is changed.

The overheat protection control performed by the MGCU 37 will be described with reference to fig. 14. The process shown in fig. 14 is repeatedly executed at a predetermined control cycle, for example.

In step S50, the upper limit rotation speed Nmlim is set to an upper limit value of the rotation speed of the rotor 22 at which the effective value of the current flowing through the stator winding 21 can be equal to or less than the allowable upper limit current (specifically, for example, the normal allowable current) while the torque of the rotary electric machine 20 is set to 0. The upper limit rotation speed Nmlim of the present embodiment is a value higher than the upper limit rotation speed Nmlim of the second embodiment.

In step S51, the upper limit rotation speed Nmlim calculated in step S50 is transmitted to the EVCU 55.

According to the present embodiment described above, the same effects as those of the second embodiment can be achieved.

< other embodiments >

The above embodiments may be modified as follows.

The EVCU 55 may also send a commanded rotational speed Nm to the MGCU 37. In this case, the MGCU 37 may calculate the command torque Trq as an operation amount for feedback-controlling the rotational speed of the rotor 22 to the received command rotational speed Nm.

The semiconductor switch constituting the inverter is not limited to an IGBT, and may be an N-channel MOSFET having a body diode built therein, for example. In this case, the high-potential side terminal of the switch is a drain, and the low-potential side terminal is a source.

The transmission may be provided in the power transmission path between the rotor 22 and the drive wheel 11.

The arithmetic functions of the EVCU 55, MGCU 37 and brake CU 62 may be integrated into one CU.

The rotating electrical machine is not limited to the in-wheel motor, and may be, for example, a so-called on-board motor included in a vehicle body.

The rotating electric machine is not limited to the star-connection rotating electric machine, and may be, for example, a delta-connection rotating electric machine.

The control section and the method thereof described in the present disclosure may also be implemented by a special purpose computer provided by constituting a processor and a memory, the processor being programmed to execute one or more functions embodied by a computer program. Alternatively, the control unit and the method of the control unit described in the present disclosure may be implemented by a special purpose computer provided by a processor configured by one or more special purpose hardware logic circuits. Alternatively, the control unit and the method of the control unit described in the present disclosure may be implemented by one or more special purpose computers configured by a combination of a processor and a memory programmed to perform one or more functions and a processor configured by one or more hardware logic circuits. Furthermore, the computer program may also be stored on a non-transitory tangible storage medium readable by a computer as instructions executed by the computer.

Although the present disclosure has been described based on the embodiments, it should be understood that the present disclosure is not limited to the above-described embodiments, constructions. The present disclosure also includes various modifications and modifications within the equivalent scope. In addition, various combinations and modes, and other combinations and modes including only one element, more than or equal to the element, are also within the scope and spirit of the present disclosure.

Claims (10)

1. A control device of a system, the control device of the system being adapted for use in a system comprising:

a rotating electrical machine (20) having a rotor (22) and a stator winding (21);

a power storage unit (31); and

an inverter (30) that has an upper arm Switch (SWH) and a lower arm Switch (SWL), and that electrically connects the stator winding with the power storage portion,

the control device of the system comprises:

a command calculation unit (55) that calculates a command value that is either a command torque (Trq) or a command rotational speed (Nm) of the rotating electrical machine; and

a rotating electrical machine control unit (37) that performs switching control of the upper arm switch and the lower arm switch based on the calculated command value to control the torque of the rotating electrical machine to the command torque,

The rotating electric machine control unit calculates an upper limit rotation speed (Nmlim) of the rotor that does not overheat the rotating electric machine and the inverter based on a driving state of the system,

the command calculation unit performs a protection process for setting the rotation speed of the rotor to the calculated upper limit rotation speed or less.

2. A control device for a system according to claim 1, wherein,

the system is included in a vehicle (10), the vehicle (10) having a drive wheel (11) rotated by transmitting power from the rotor,

as the protection process, the command calculation unit calculates an upper limit running speed (Vslim) of the vehicle when the rotation speed of the rotor becomes the upper limit rotation speed,

processing is performed to set the running speed of the vehicle to the upper limit running speed or lower.

3. A control device for a system according to claim 2, wherein,

as the protection processing, the command calculation unit performs processing for reducing the command value used in the rotating electrical machine control unit so that the running speed of the vehicle becomes equal to or lower than the upper limit running speed.

4. A control device for a system according to claim 2 or 3,

The vehicle comprises a mechanical brake device (60) for applying a braking force to the driving wheels,

as the protection processing, the command calculation unit performs processing for setting the running speed of the vehicle to the upper limit running speed or lower by applying a braking force to the driving wheels by the brake device.

5. A control device for a system according to any one of claims 1 to 4,

the rotating electrical machine control unit performs the switching control so that a field weakening current flows through the stator winding when the rotational speed of the rotor is equal to or greater than a speed threshold (Nth),

the upper limit rotation speed is set as the speed threshold.

6. A control device for a system according to any one of claims 1 to 4,

the rotating electrical machine control unit sets the upper limit rotation speed to a rotation speed of the rotor at which a peak value of a line-to-line voltage induced in the stator winding by rotation of the rotor including the excitation pole is identical to a voltage of the power storage unit.

7. A control device for a system according to claim 6, wherein,

the upper limit rotation speed is a rotation speed of the rotor in which a peak value of the line-to-line voltage when a temperature of the excitation pole included in the rotor is set to a lower limit value of a range of values of the temperature is equal to a voltage of the power storage unit.

8. A control device for a system according to any one of claims 1 to 4,

the rotating electrical machine control unit sets the upper limit rotation speed to an upper limit value of the rotation speed of the rotor at which the current flowing through the stator winding is equal to or less than an allowable upper limit current while setting the torque of the rotating electrical machine to 0.

9. A control device for a system according to any one of claims 1 to 8,

as a driving state of the system, the rotating electrical machine control unit calculates the upper limit rotation speed using at least one of a frequency of a carrier signal when the switching control is performed by PWM control, a dead time when the switching control is performed, a voltage of the power storage unit, and a temperature of an excitation pole included in the rotor.

10. A program adapted to a system, the system comprising:

a rotating electrical machine (20) having a rotor (22) and a stator winding (21);

a power storage unit (31);

an inverter (30) that has an upper arm Switch (SWH) and a lower arm Switch (SWL), and that electrically connects the stator winding with the power storage portion; and

a computer (37 a, 55 a),

The following processing is performed in the computer:

a process of calculating a command value that is either one of a command torque (Trq) or a command rotational speed (Nm) of the rotating electrical machine;

performing switching control of the upper arm switch and the lower arm switch based on the calculated command value to control the torque of the rotating electrical machine to the command torque;

a process of calculating an upper limit rotation speed (Nmlim) of the rotor that does not cause the rotating electric machine and the inverter to be in a overheated state, based on a driving state of the system;

a process of transmitting the calculated upper limit rotation speed to the first computer; and

and a protection process of setting the rotation speed of the rotor to be equal to or lower than the received upper limit rotation speed.