WO2024057448A1

WO2024057448A1 - Electronic control device

Info

Publication number: WO2024057448A1
Application number: PCT/JP2022/034430
Authority: WO
Inventors: 泰亮佐藤; 滋久青柳; 正悟宮本; 貴哉塚越
Original assignee: 日立Astemo株式会社
Priority date: 2022-09-14
Filing date: 2022-09-14
Publication date: 2024-03-21

Abstract

The present disclosure provides an electronic control device that is capable of limiting noise from an electric motor when switching carrier frequencies. This electronic control device controls an electric motor for the travel of a vehicle, the device including a switching condition storage unit (122), a traveling load computing unit (121), a switching condition determining unit (123), and a frequency control unit (124). The switching condition storage unit (122) stores a switching condition in which the rotation speed of the electric motor is less than a predetermined lower limit value and a torque command of the electric motor is higher than a predetermined upper limit value. The traveling load computing unit (121) calculates a traveling load (Lt) of the vehicle on the basis of the rotation speed (ω) and the torque command (Tc) of the electric motor. The switching condition determining unit (123) determines whether the switching condition is satisfied after a predetermined time period has elapsed, on the basis of the traveling load (Lt) of the vehicle and the rotation speed (ω) and the torque command (Tc) of the electric motor. When the switching condition determining unit (123) has determined that the switching condition is satisfied, the frequency control unit (124) reduces the carrier frequency of the electric motor when the torque command of the electric motor is equal to or less than the upper limit value.

Description

electronic control unit

The present disclosure relates to an electronic control device that controls an electric motor.

The invention of a power output device that outputs power for driving has been conventionally known (see Patent Document 1 below). This conventional power output device includes, for example, a plurality of electric motors capable of outputting driving power, a plurality of drive circuits that respectively drive these plurality of electric motors, and a request to set required power based on an operator's operation. It includes a power setting means and a control means for driving and controlling a plurality of drive circuits (Patent Document 1, paragraph 0006, claim 1, abstract, etc.).

The plurality of drive circuits each have a switching element, and drive each of the plurality of electric motors by switching the switching element. The control means drives and controls the plurality of drive circuits so that when any of the plurality of drive circuits is in a normal state where it can function normally, the plurality of electric motors output power based on the set required power. . Furthermore, when any one of the plurality of drive circuits is in an abnormal state in which it cannot function normally, the control means drives and controls the plurality of drive circuits as follows.

That is, the control means controls the plurality of drive circuits based on the switching frequency of the switching element of the drive circuit in the abnormal state and the power from the electric motor driven by the drive circuit in the abnormal state. Drive control. More specifically, of the switching frequency and the power, the power is limited in priority to the switching frequency, and the power based on the set required power is output from the plurality of electric motors. drive control of multiple drive circuits so that

This conventional power output device can reduce the burden on the drive circuit that is in an abnormal state while suppressing the generation of noise caused by switching of switching elements included in the drive circuit that is in an abnormal state. As a result, it is possible to achieve both good driving of the driving circuit and suppression of noise caused by the driving. Further, the required power can be met regardless of whether any of the plurality of drive circuits is in a normal state (Patent Document 1, paragraph 0007).

Japanese Patent Application Publication No. 2006-197717

In the conventional power output device described above, for example, torque is distributed among multiple electric motors until the temperature of the drive circuit reaches a temperature limit, so the carrier frequency may not be switched while the electric motor is outputting high torque. be. In this way, if the carrier frequency is switched while the electric motor is outputting high torque, there is a risk that noise will be generated from the electric motor.

The present disclosure provides an electronic control device that can suppress motor noise when switching carrier frequencies.

One aspect of the present disclosure is an electronic control device that controls an electric motor for driving a vehicle, wherein a switching condition is such that the rotation speed of the electric motor is lower than a predetermined lower limit value and the torque command of the electric motor is higher than a predetermined upper limit value. a stored switching condition storage unit, a running load calculation unit that calculates a running load of the vehicle based on the rotational speed and torque command of the electric motor, and a running load calculation unit that calculates the running load of the vehicle based on the rotational speed and torque command of the electric motor; a switching condition determining unit that determines whether the switching condition is satisfied after a predetermined time has elapsed based on the switching condition, and when the switching condition determining unit determines that the switching condition is satisfied, the torque command of the electric motor is set to the upper limit The electronic control device is characterized in that it has a frequency control section that lowers the carrier frequency of the electric motor when the carrier frequency is equal to or less than the carrier frequency of the electric motor.

According to the above-described aspect of the present disclosure, it is possible to provide an electronic control device that can suppress the noise of the electric motor when switching the carrier frequency.

FIG. 1 is a block diagram showing an embodiment of an electronic control device of the present disclosure. FIG. 2 is a block diagram of a torque control section that constitutes the electronic control device of FIG. 1; FIG. 2 is a block diagram of a three-phase current control section that constitutes the electronic control device of FIG. 1. FIG. 4 is a graph illustrating a switching condition storage section that constitutes the three-phase current control section in FIG. 3. 4 is a graph illustrating a switching condition storage section that constitutes the three-phase current control section in FIG. 3. FIG. 4 is a block diagram of a PWM control section that constitutes the three-phase current control section in FIG. 3; FIG. 2 is a flow diagram illustrating the operation of the electronic control device in FIG. 1. FIG. FIG. 2 is a state transition diagram of the vehicle under control of the electronic control device of FIG. 1. FIG. 9 is a graph of torque commands, etc. of the electric motor in state (i) of FIG. 8. 9 is a graph showing a torque command etc. of the electric motor in state (ii) of FIG. 8 . 9 is a graph of torque commands, etc. of the electric motor in state (iii) of FIG. 8. 9 is a graph of torque commands, etc. of the electric motor in state (iv) of FIG. 8. 9 is a graph of the torque command, etc. of the electric motor in state (v) of FIG. 8. 9 is a graph of torque commands, etc. of the electric motor in state (vi) of FIG. 8.

Hereinafter, embodiments of an electronic control device according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of an electronic control device according to the present disclosure. The electronic control device 100 of this embodiment is, for example, an electronic control device that is mounted on a vehicle 10 such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, and controls an electric motor 11 for driving the vehicle 10. Although not shown in FIG. 1, the vehicle 10 includes, for example, a steering device, a braking device, a power transmission device, a power storage device, and the like that are generally included in a normal vehicle.

In the example shown in FIG. 1, the vehicle 10 is driven by two motors: a first electric motor 11F that drives left and right front wheels 13F via a gear 12F, and a second electric motor 11R that drives left and right rear wheels 13R via a gear 12R. It has an electric motor 11 for use. The vehicle 10 also includes, for example, an accelerator position sensor 14 that detects the opening degree of the accelerator pedal, and an acceleration sensor 15 that detects the acceleration of the vehicle 10 in the longitudinal direction.

Furthermore, in the example shown in FIG. 1, the vehicle 10 includes, for example, an ABS control section 16 that constitutes an anti-lock brake system (ABS), and a TCS control section 17 that constitutes a traction control system (TCS). . Further, although not shown in FIG. 1, the vehicle 10 includes various sensors that are generally included in a normal vehicle. Further, the vehicle 10 only needs to have at least one electric motor 11 for traveling, and may have four or more electric motors 11 (in-wheel motors) that drive each wheel 13.

The electronic control device 100 is configured by, for example, a plurality of microcontrollers (not shown) and a plurality of electronic circuits including a plurality of electronic components. Each microcontroller making up the electronic control device 100 has, for example, an input/output section, a memory, a timer, and a central processing unit (CPU). The electronic control device 100 realizes various functions described below by, for example, executing programs stored in a memory using a CPU.

In the example shown in FIG. 1, the electronic control device 100 includes, for example, a torque control section 110 and a three-phase current control section 120. Further, the electronic control device 100 may include an inverter 130, for example. The electronic control device 100 includes, for example, a first three-phase current control section 120F and a first inverter 130F that control a first electric motor 11F, and a second three-phase current control section 120R and a first inverter that control a second electric motor 11R. 2 inverters 130R. That is, one three-phase current control section 120 and one inverter 130 are provided for each electric motor 11.

The torque control unit 110 receives, for example, the accelerator pedal operation amount Qac from the accelerator position sensor 14 and the longitudinal acceleration α of the vehicle 10 from the acceleration sensor 15. Further, the torque control unit 110 receives, for example, a control signal Sab related to anti-lock brakes from the ABS control unit 16, and a control signal Stc related to traction control from the TCS control unit 17.

Further, the torque control unit 110 receives, for example, the rotational speed ω of the electric motor 11 from the three-phase current control unit 120. In the example shown in FIG. 1, the torque control unit 110 receives, for example, the rotational speed ωF of the first electric motor 11F from the first three-phase current control unit 120F, and the rotation speed ωF of the first electric motor 11F from the second three-phase current control unit 120R. The rotational speed ωR of 11R is input.

The torque control unit 110 sets the torque command Tc and the torque change rate limit based on, for example, the input accelerator pedal operation amount Qac, the acceleration α of the vehicle 10, the rotational speed ω of the electric motor 11, and the control signals Sab and Stc. Output ΔTr. More specifically, the torque control unit 110 outputs a torque command TcF and a torque change rate limit ΔTrF for the first electric motor 11F, and a torque command TcR and a torque change rate limit ΔTrR for the second electric motor 11R.

The three-phase current control unit 120 receives the torque command Tc and torque change rate limit ΔTr for the electric motor 11 from the torque control unit 110. More specifically, the first three-phase current control section 120F receives the torque command TcF and the torque change rate limit ΔTrF for the first electric motor 11F from the torque control section 110. Further, the second three-phase current control section 120R receives input from the torque control section 110 of the torque command TcR and the torque change rate limit ΔTrR for the second electric motor 11R.

Furthermore, the rotation angle θ is input to the three-phase current control unit 120 from the electric motor 11. More specifically, the first three-phase current control section 120F receives the rotation angle θF from the first electric motor 11F, and the second three-phase current control section 120R receives the rotation angle θR from the second electric motor 11R. Ru.

Furthermore, the three-phase current control unit 120 receives an inverter voltage Vin from the inverter 130. More specifically, the first three-phase current control section 120F receives the inverter voltage VinF from the first inverter 130F, and the second three-phase current control section 120R receives the inverter voltage VinR from the second inverter 130R. is input.

Additionally, the three-phase current control unit 120 receives three-phase currents Iu, Iv, and Iw from the inverter 130. More specifically, the first three-phase current control section 120F and the second three-phase current control section 120R receive three-phase currents Iu, Iv, and Iw from the first inverter 130F and the second inverter 130R, respectively. be done.

The three-phase current control section 120 outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz based on the above-mentioned inputs. More specifically, the first three-phase current control section 120F outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz to the first inverter 130F, and the second three-phase current control section 120R outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz to the first inverter 130F. Gate signals Iu, Iv, Iw, Ix, Iy, and Iz are output to the second inverter 130R.

The inverter 130 is connected to the power supply voltage Vs, for example, and receives gate signals Iu, Iv, Iw, Ix, Iy, and Iz from the three-phase current control section 120. More specifically, the first inverter 130F and the second inverter 130R receive gate signals Iu, Iv, Iw, Ix, Iy and Iz are input.

Based on the above input, the inverter 130 outputs, for example, three-phase currents Iu, Iv, and Iw to the electric motor 11, and outputs an inverter voltage Vin to the three-phase current control section 120. More specifically, the first inverter 130F and the second inverter 130R output three-phase currents Iu, Iv, and Iw to the first electric motor 11F and the second electric motor 11R, respectively. Further, the first inverter 130F and the second inverter 130R output inverter voltages VinF and VinR to the first three-phase current control section 120F and the second three-phase current control section 120R, respectively.

FIG. 2 is a block diagram of the torque control section 110 that constitutes the electronic control device 100 in FIG. 1. The torque control section 110 includes, for example, a required torque generation section 111, a running load calculation section 112, a control torque generation section 113, and a torque command generation section 114.

The required torque generation unit 111 receives, for example, the accelerator pedal operation amount Qac and the rotational speed ω (ωF, ωR) of each electric motor 11. Based on these inputs, the required torque generation unit 111 calculates, for example, the total required torque RTT, the required torque RTF of the first electric motor 11F, and the required torque RTR of the second electric motor 11R, and generates the torque command generation unit. 114.

The running load calculation unit 112 receives, for example, the rotational speed ω (ωF, ωR) of each electric motor 11 and the acceleration α of the vehicle 10 as input. The running load calculation unit 112 estimates the running resistance value due to the slope from the rotational speed ω of the electric motor 11 and the acceleration α of the vehicle 10. Further, the running load calculation unit 112 uses the estimated running resistance value, the weight and front projected area of the vehicle 10 stored in the memory, and calculates the running load Lt of the vehicle 10 and outputs it to the torque command generation unit 114. do.

The control torque generation unit 113 receives, for example, the control signal Sab from the ABS control unit 16 and the control signal Stc from the TCS control unit 17. Based on these inputs, control torque generation section 113 calculates control torque CT required for control to stabilize vehicle 10, such as anti-lock brakes and traction control, and outputs it to torque command generation section 114.

For example, the torque command generation unit 114 receives the total required torque RTT, required torque RTF, and required torque RTR from the required torque generation unit 111, and receives the rotational speed ω of each electric motor 11 from each three-phase current control unit 120. is input. Further, the torque command generation unit 114 receives the running load Lt from the running load calculation unit 112 and receives the control torque CT from the control torque generation unit 113. The torque command generation unit 114 calculates the torque command Tc (TcF, TcR) and torque change rate limit ΔTr (ΔTrF, ΔTrR) for each electric motor 11 based on these inputs, Output to 120.

FIG. 3 is a block diagram of the three-phase current control section 120 that constitutes the electronic control device 100 of FIG. 1. The three-phase current control unit 120 includes, for example, a running load calculation unit 121, a switching condition storage unit 122, a switching condition determination unit 123, a frequency control unit 124, and a pulse width modulation (PWM) control unit 125. It has .

The running load calculation unit 121 estimates the running resistance value of the vehicle 10 due to the slope, for example, by inputting the torque command Tc and rotational speed ω of each electric motor 11. Furthermore, the running load calculation unit 121 calculates the running load Lt of the vehicle 10 from the running resistance value, the weight of the vehicle 10, the rotational speed ω of each electric motor 11, the front projected area of the vehicle 10, etc. It is output to the condition determination section 123.

4 and 5 are graphs explaining the switching condition storage section 122, which is a part of the three-phase current control section 120 in FIG. 3. More specifically, in the graph of FIG. 4, the horizontal axis represents the rotational speed ω of the electric motor 11, the vertical axis represents the torque command Tc of the electric motor 11, and shows the operating range OA and the switching area SA of the electric motor 11.

The switching region SA is, for example, a region where the rotational speed ω of the electric motor 11 is less than or equal to a predetermined lower limit value ωl, and the torque command Tc of the electric motor 11 is greater than or equal to a predetermined upper limit value Tch. In this switching region SA, it is necessary to lower the carrier frequency of the electric motor 11 in order to protect the inverter 130. That is, the graph shown in FIG. 4 represents the switching conditions under which carrier frequency switching is required as the switching area SA.

However, if the carrier frequency of the electric motor 11 is switched in a state where the relationship between the torque command Tc and the rotational speed ω of the electric motor 11 is within the switching region SA, noise is generated. Therefore, in the switching area SA, it is necessary to avoid switching the carrier frequency of the electric motor 11. That is, the switching area SA is also a restricted area in which switching of the carrier frequency should be restricted from the viewpoint of suppressing the noise of the electric motor 11.

In addition, in the graph of FIG. 5, the horizontal axis is the rotational speed ω of the electric motor 11, and the vertical axis is the torque command Tc of the electric motor 11, and the torque command Tc of the electric motor 11 and The relationship with rotational speed ω is shown. As shown in FIG. 5, as the running load Lt increases, the change in the torque command Tc with respect to the change in the rotational speed ω of the electric motor 11 increases. The graphs in FIGS. 4 and 5 are created for each electric motor 11, set and recorded in the switching condition storage section 122, and output from the switching condition storage section 122 to the switching condition determination section 123 as necessary.

The switching condition determining unit 123 receives, for example, the torque command Tc, torque change rate limit ΔTr, and rotational speed ω of each electric motor 11, and the running load Lt of the vehicle 10. The switching condition determination unit 123 obtains, for example, the operating range OA and switching range SA of each electric motor 11 shown in FIG. Obtain the relationship with ω. As described above, the switching area SA represents a switching condition that requires switching the carrier frequency of the electric motor 11.

For example, the switching condition determining unit 123 determines whether the relationship between the torque command Tc and the rotational speed ω of each electric motor 11 is a predetermined value based on the above input, the switching area SA shown in FIG. 4, and the relationship shown in FIG. After a period of time has elapsed, it is determined whether or not the switching area SA is entered. Whether or not the switching region SA is entered has the same meaning as whether or not the switching condition that requires lowering the carrier frequency of the electric motor 11 is satisfied. More specifically, the switching condition determination unit 123 superimposes the graphs in FIGS. 4 and 5, and determines whether each electric motor It is determined that the relationship between the torque command Tc and the rotational speed ω of No. 11 satisfies the switching condition after a predetermined period of time has elapsed.

The switching condition determining unit 123 determines whether the relationship between the torque command Tc and the rotational speed ω of the electric motor 11 falls within the switching region SA after a predetermined period of time has elapsed, that is, whether the rotational speed ω is lower than the lower limit value ωl and the torque command Tc is lower than the lower limit ωl. A determination result DR as to whether the switching condition greater than the upper limit Tch is satisfied is output to the frequency control unit 124.

For example, the frequency control unit 124 outputs a control signal Cfc that lowers the carrier frequency of the electric motor 11 to be controlled to the PWM control unit 125, based on the determination result DR input from the switching condition determination unit 123. More specifically, if the determination result DR is affirmative, the frequency control unit 124 determines that the relationship between the torque command Tc and the rotational speed ω of the electric motor 11 to be controlled satisfies the switching condition after a predetermined period of time has elapsed. If determined, the control signal Cfc is output.

FIG. 6 is a block diagram of the PWM control section 125, which is a part of the three-phase current control section 120 in FIG. 3. The PWM control unit 125 inputs the three-phase currents Iu, Iv, Iw of each electric motor 11, the rotation angle θ, the torque command Tc, the inverter voltage Vin, and the control signal Cfc of the frequency control unit 124, and receives the gate signals Iu, Iv, Iw, Ix, Iy, Iz and rotational speed ω are output.

The PWM control unit 125 has, for example, a speed calculation unit 125a, a three-phase/dq conversion calculation unit 125b, a current command generation unit 125c, a current control unit 125d, a dq/three-phase conversion calculation unit 125e, and a PWM calculation unit 125f. Each of these units has a general configuration for vector control of the electric motor 11, which is a permanent magnet motor, so a description thereof will be omitted. The PWM control unit 125 lowers the carrier frequency of the power switching device in the inverter 130, for example, based on a control signal Cfc that lowers the carrier frequency of each electric motor 11.

Hereinafter, the operation of the electronic control device 100 of this embodiment will be explained with reference to FIGS. 7 to 14. FIG. 7 is a flow diagram illustrating the operation of the electronic control device 100. FIG. 8 is a state transition diagram of the vehicle 10 under control of the electronic control device 100.

A state (o) shown in FIG. 8 indicates a state in which the electric motor 11 (11F, 11R) is not controlled by the electronic control device 100, such as a state in which the vehicle 10 is stopped. From this state (o), for example, when the electronic control device 100 starts controlling the electric motor 11 and the vehicle 10 starts running, the vehicle 10 transitions to, for example, the state (i) shown in FIG. The device 100 executes the process P1 shown in FIG. State (i) is, for example, a state in which the running load Lt of the vehicle 10 is low and switching of the carrier frequency of the electric motor 11 is unnecessary.

In the process P1 shown in FIG. 7, the torque control unit 110 of the electronic control device 100 includes, for example, the accelerator pedal operation amount Qac, the acceleration α of the vehicle 10, the control of the ABS control unit 16 and the TCS control unit 17, as described above. Signals Sab and Stc are input. Based on these inputs, the torque control unit 110 outputs the torque command Tc and the torque change rate limit ΔTr to each three-phase current control unit 120 that controls each electric motor 11, as described above.

Next, the electronic control device 100 executes a process P2 of acquiring switching conditions. In this process P2, the switching condition determination unit 123 constituting the three-phase current control unit 120 of the electronic control device 100 determines, for example, the operating area OA and switching area SA in FIG. 4 and the running area SA in FIG. The relationship between the torque command Tc and the rotational speed ω according to the load Lt is acquired from the switching condition storage unit 122.

Next, the electronic control device 100 executes a process P3 to determine whether the switching condition is appropriate. In this process P3, the switching condition determination unit 123 of the electronic control device 100 receives the torque command Tc, torque change rate limit ΔTr, and rotational speed ω of each electric motor 11, as well as the running load Lt of the vehicle 10, as described above. is input. The switching condition determining unit 123 determines whether each electric motor 11 satisfies the switching condition after a predetermined period of time has passed, based on these inputs and the graphs of FIGS. 4 and 5 obtained in the previous process P2, for example. judge.

FIG. 9 is a graph showing an example of the torque command Tc (TcF, TcR) of each electric motor 11, the carrier frequency, and the total torque of all electric motors 11 in state (i) of the vehicle 10 in FIG. In the graphs of the first and second torque commands TcF and TcR from the top in FIG. 9, the maximum torques T1max and T2max of the first electric motor 11F and the second electric motor 11R, respectively, and the noise at the time of carrier frequency switching are sufficiently suppressed. Possible torques T1q and T2q are shown.

In this state (i) of the vehicle 10, the running load Lt is relatively small, so as shown in FIG. 5, the change in the torque command Tc with respect to the change in the rotational speed ω of each electric motor 11 is relatively small. As a result, the torque commands Tc (TcF, TcR) of each electric motor 11 after a predetermined period of time do not enter the switching area SA shown in FIG. 4, and the switching conditions are not satisfied after a predetermined period of time has elapsed.

In this case, in process P3 shown in FIG. 7, the switching condition determining unit 123 determines that the switching condition is not satisfied after a predetermined time (NO), and the electronic control device 100 does not execute process P4, which will be described later. Process P5 is executed. In process P5, the PWM control section 125f that constitutes the PWM control section 125 of the three-phase current control section 120 generates a control signal Cfc for lowering the carrier frequency and a gate signal Iu, which corresponds to the command voltages Vu ^* , Vv ^* , Vw ^* . Outputs Iv, Iw, Ix, Iy, and Iz.

Here, the torque control unit 110 controls the torque control unit 110 so that, for example, the relationship between the torque commands TcF, TcR and the rotational speeds ωF, ωR of the first electric motor 11F and the second electric motor 11R does not fall into the switching region SA shown in FIG. Torque may be distributed between the first electric motor 11F and the second electric motor 11R.

The same applies when the vehicle 10 has four or more electric motors 11. That is, the torque control unit 110 appropriately distributes torque among the plurality of electric motors 11 so that the relationship between the torque command Tc and the rotational speed ω does not fall within the switching region SA, and carrier frequency switching is not necessary. Good too. Further, in this process P5, the torque control unit 110 does not change the torque change rate limit ΔTr, for example.

Each inverter 130 outputs three-phase currents Iu, Iv, Iw to each electric motor 11 based on input gate signals Iu, Iv, Iw, Ix, Iy, Iz. As a result, each electric motor 11 rotates to rotate the left and right front wheels 13F and the left and right rear wheels 13R via the

gears

12F and 12R, thereby causing the vehicle 10 to travel. After that, the electronic control device 100 ends the process shown in FIG. 7, for example, and repeatedly executes the process at a predetermined period.

For example, when the running load Lt increases due to, for example, running uphill immediately after the vehicle 10 starts running, the state of the vehicle 10 transitions from the state (o) shown in FIG. 8 to the state (ii). State (ii) is, for example, a state in which the running load Lt of vehicle 10 is higher than state (i), and carrier frequency switching is required in order to protect inverter 130 in some of the plurality of electric motors 11.

In the electronic control device 100 of the present embodiment, state (ii) is, for example, when the carrier frequency of the second electric motor 11R is between the first electric motor 11F that drives the front wheels 13F and the second electric motor 11R that drives the rear wheels 13R. The state requires switching. When the electronic control device 100 executes the above-mentioned process P3 in this state (ii), for example, as shown in FIG. The change in torque command Tc (TcR) with respect to the change in is larger than in the above-mentioned state (i).

As a result, the switching condition determination unit 123 determines that, for example, in process P3, the relationship between the torque command TcR and the rotational speed ωR of the second electric motor 11R enters the switching region SA shown in FIG. It is determined that the conditions are satisfied (YES). Further, the switching condition determination unit 123 determines that, for example, in process P3, the relationship between the torque command TcF and the rotational speed ωF of the first electric motor 11F does not fall within the switching region SA shown in FIG. It is determined that the conditions are not satisfied (NO). Thereafter, the frequency control unit 124 outputs the determination result DR of process P3 to the PWM control unit 125.

In process P3, for example, when it is determined that the switching condition is satisfied in at least one electric motor 11 after a predetermined time has elapsed (YES), the electronic control device 100 executes the next process P4. In this process P4, the electronic control device 100 performs torque distribution among the plurality of electric motors 11, and lowers the carrier frequency of the electric motor 11 that is determined to satisfy the switching condition after a predetermined period of time has elapsed.

FIG. 10 shows an example of the torque command Tc (TcF, TcR) of each electric motor 11, carrier frequency, and total torque of all electric motors 11 (11F, 11R) in state (ii) of the vehicle 10 in FIG. It is a graph. The first and second graphs of torque commands TcF and TcR from the top in FIG. 10 show torques T1q and T2q that can sufficiently suppress noise when switching the carrier frequency.

In process P4, the electronic control device 100, for example, sends a control signal Cfc that lowers the carrier frequency from the frequency control section 124 to the PWM control section 125 in the second three-phase current control section 120R that controls the second electric motor 11R. Output. Here, the frequency control unit 124 transmits the control signal Cfc to the PWM control unit 125, for example, before the torque command TcR of the second electric motor 11R exceeds the torque T2q that can sufficiently suppress noise at the time of carrier frequency switching. Output.

As a result, as shown in the second graph from the top and the second graph from the bottom in FIG. 10, the carrier frequency of the second electric motor 11R changes to down to a predetermined frequency that can be protected. Thereby, the noise generated when lowering the carrier frequency of the second electric motor 11R that drives the rear wheels 13R of the vehicle 10 can be sufficiently suppressed.

Note that before the curve indicating the relationship between the torque command TcR of the second electric motor 11R and the rotational speed ωR enters the switching region SA, that is, when the torque command TcR of the second electric motor 11R is equal to or lower than the upper limit value Tch, the second electric motor By lowering the carrier frequency of 11R, it is possible to obtain a noise suppression effect.

Furthermore, in process P4 shown in FIG. 7, the electronic control device 100 distributes torque to the plurality of electric motors 11, for example, by the torque control unit 110. More specifically, for example, the torque command generation unit 114 shown in FIG. Allocate.

In the graphs of the first and second torque commands TcF and TcR from the top in FIG. It shows. This upper limit Tch is an upper limit for preventing the curves showing the relationship between the torque command Tc and rotational speed ω of each of the first electric motor 11F and the second electric motor 11R shown in FIG. 5 from falling into the switching area SA shown in FIG. The value is Tch.

In process P4, the torque control unit 110 controls the first electric motor 11F and the second electric motor so that, for example, the torque command TcF of the first electric motor 11F that drives the front wheels 13F of the vehicle 10 does not enter the switching area SA shown in FIG. Distribute the torque of 11R. More specifically, the torque control unit 110 limits the torque command TcF of the first electric motor 11F that does not reduce the carrier frequency to below the upper limit value Tch.

In addition, the torque control unit 110 increases the torque command TcR of the second electric motor 11R, which has a lower carrier frequency, beyond the upper limit value Tch within a range that does not exceed the maximum torque T2max. Further, in process P4, the torque control unit 110, for example, reduces the torque change rate limit ΔTrR of the second electric motor 11R, and does not change the torque change rate limit ΔTrF of the first electric motor 11F.

After that, the electronic control device 100 executes the above-mentioned process P5, for example, and ends the process shown in FIG. 7. As a result, the torque that is insufficient by limiting the torque command TcF of the first electric motor 11F to below the upper limit value Tch is supplemented by the torque of the second electric motor 11R, and the desired total torque is achieved by the first electric motor 11F and the second electric motor 11R. It becomes possible to output.

Further, when the vehicle 10 travels on a steep uphill slope and the running load Lt increases significantly or due to sudden acceleration, the state of the vehicle 10 changes from state (o) to state (iii) shown in FIG. 8, for example. . In state (iii), for example, the running load Lt of vehicle 10 is higher than state (ii), and it is necessary to switch carrier frequencies in all electric motors 11 to protect inverters 130.

In the electronic control device 100 of the present embodiment, state (iii) is, for example, a state in which the carrier frequency of both the first electric motor 11F that drives the front wheels 13F and the second electric motor 11R that drives the rear wheels 13R needs to be switched. It is. When the electronic control device 100 executes the above-mentioned process P3 in this state (iii), the running load Lt of the vehicle 10 increases, for example, as shown in FIG. 5, the first electric motor 11F and the second electric motor 11R The change in torque command Tc (TcF, TcR) with respect to the change in rotational speed ω (ωF, ωR) becomes larger than in state (ii).

As a result, in process P3, for example, the switching condition determining unit 123 determines that the relationship between the torque commands TcF, TcR and the rotational speeds ωF, ωR of the first electric motor 11F and the second electric motor 11R is as shown in FIG. It enters the switching area SA shown in and determines that the switching conditions are satisfied (YES). Thereafter, the frequency control section 124 outputs this determination result DR to the PWM control section 125.

After that, the electronic control device 100 executes the next process P4, for example. In this process P4, the electronic control device 100 lowers the carrier frequencies of both the first electric motor 11F and the second electric motor 11R, which are determined to satisfy the switching condition after a predetermined period of time has elapsed, and Torque is distributed between the two electric motors 11R.

FIG. 11 is a graph showing an example of the torque command Tc (TcF, TcR) of the electric motor 11, the carrier frequency, and the total torque of all the electric motors 11 (11F, 11R) in state (iii) of FIG. 8. The first and second graphs of torque commands TcF and TcR from the top in FIG. 11 show torques T1q and T2q that can sufficiently suppress noise when switching the carrier frequency.

In process P4, the electronic control device 100 lowers the carrier frequency from the frequency control section 124 to the PWM control section 125 in each three-phase current control section 120 that controls the first electric motor 11F and the second electric motor 11R. Outputs control signal Cfc. Here, the frequency control unit 124 of each three-phase current control unit 120 is configured such that, for example, each torque command TcF, TcR of the first electric motor 11F and the second electric motor 11R sufficiently suppresses noise at the time of carrier frequency switching. A control signal Cfc is output to the PWM control unit 125 before each possible torque T1q, T2q is exceeded.

As a result, as shown in FIG. 11, before the torque commands TcF and TcR of the first electric motor 11F and the second electric motor 11R exceed the torques T1q and T2q, the carrier frequencies of the first electric motor 11F and the second electric motor 11R change. is lowered to a predetermined frequency that can protect the inverter 130. Thereby, the noise generated when lowering the carrier frequency of the first electric motor 11F and the second electric motor 11R of the vehicle 10 can be sufficiently suppressed.

Note that before the torque commands TcR of the first electric motor 11F and the second electric motor 11R exceed the upper limit value Tch and enter the switching area SA, that is, before the switching conditions are satisfied, the first electric motor 11F and the second electric motor 11R It is possible to obtain a noise suppression effect by lowering the carrier frequency of. Further, in this process P4, the electronic control device 100, for example, uses the torque control unit 110 to appropriately distribute torque to the first electric motor 11F and the second electric motor 11R.

After that, the electronic control device 100 executes the above-mentioned process P5, for example, and ends the process shown in FIG. 7. As described above, in state (iii) of the vehicle 10, the electronic control device 100 controls the first electric motor 11F and The carrier frequency of the second electric motor 11R is lowered. Thereby, noise generated when lowering the carrier frequency of the first electric motor 11F and the second electric motor 11R of the vehicle 10 can be suppressed.

Further, as shown in FIG. 8, the state (i) in which the running load Lt of the vehicle 10 is low and there is no need to lower the carrier frequencies of all electric motors 11 is a state in which, for example, due to an increase in the running load Lt of the vehicle 10, After (iv), the state transitions to the above-mentioned state (ii). In state (iv), for example, the running load Lt of vehicle 10 is higher than in state (i), and it is necessary to switch carrier frequencies in some of the plurality of electric motors 11 to protect inverter 130.

In the electronic control device 100 of this embodiment, the state (iv) is, for example, the carrier frequency of the second electric motor 11R among the first electric motor 11F that drives the front wheels 13F and the second electric motor 11R that drives the rear wheels 13R. The state requires switching. When the electronic control device 100 executes the above-mentioned process P3 in this state (iv), the switching condition determination unit 123 determines that the relationship between the torque command TcR and the rotational speed ωR of the second electric motor 11R is as shown in FIG. It enters the switching area SA shown and determines that the switching conditions are satisfied (YES). Thereafter, the frequency control section 124 outputs this determination result DR to the PWM control section 125.

After that, the electronic control device 100 executes the next process P4, for example. In this process P4, the electronic control device 100 first performs torque distribution between the first electric motor 11F and the second electric motor 11R, and then lowers the carrier frequency of the second electric motor 11R.

FIG. 12 is a graph showing an example of the torque command Tc (TcF, TcR) of the electric motor 11, the carrier frequency, and the total torque of all the electric motors 11 (11F, 11R) in state (iv) of FIG. 8. In process P4, before the frequency control unit 124 reduces the carrier frequency of the second electric motor 11R, the torque control unit 110, for example, reduces the torque command TcR of the second electric motor 11R and increases the torque command TcF of the first electric motor 11F to maintain the total torque at a constant value. At this time, the torque control unit 110, for example, increases the torque change rate limits ΔTrF, ΔTrR of the first electric motor 11F and the second electric motor 11R.

Thereafter, when the torque command TcR of the second electric motor 11R decreases to a predetermined value that can suppress noise caused by carrier frequency switching, the frequency control unit 124 outputs a control signal Cfc to the PWM control unit 125, The carrier frequency of the second electric motor 11R is lowered. Thereby, noise caused by switching the carrier frequency of the second electric motor 11R can be suppressed.

For example, the torque control unit 110 reduces the torque change rate limit ΔTrR at a timing when the carrier frequency of the second electric motor 11R is desired to be switched. Further, the torque control unit 110 increases the torque command TcR of the second electric motor 11R and switches the torque command TcF of the first electric motor 11F, for example, after the frequency control unit 124 decreases the carrier frequency of the second electric motor 11R. It is limited to below the upper limit value Tch that falls within the area SA. This eliminates the need to switch the carrier frequency of the first electric motor 11F, and can prevent the generation of noise when switching the carrier frequency with high torque.

Further, as shown in FIG. 8, the state (i) in which the running load Lt of the vehicle 10 is low and there is no need to lower the carrier frequencies of all electric motors 11 is a state in which, for example, the running load Lt of the vehicle 10 suddenly increases. This causes a transition to the above-mentioned state (iii) via state (v). In state (v), for example, the running load Lt of vehicle 10 is higher than in state (ii), and it is necessary to switch carrier frequencies for protection of inverter 130 in all electric motors 11.

When the electronic control device 100 executes the above-mentioned process P3 in this state (v), the switching condition determination unit 123 determines that the respective torque commands TcF, TcR and rotational speeds ωF, ωR of the first electric motor 11F and the second electric motor 11R It is determined that the relationship enters the switching area SA shown in FIG. 4 after a predetermined period of time has passed and that the switching condition is satisfied (YES). The switching condition determining section 123 outputs this determination result DR to the frequency controlling section 124.

After that, the electronic control device 100 executes the next process P4, for example. In this process P4, the electronic control device 100 first lowers the carrier frequency of the second electric motor 11R, then performs torque distribution between the first electric motor 11F and the second electric motor 11R, and then Lower the carrier frequency of 11F.

FIG. 13 is a graph showing an example of the torque command Tc (TcF, TcR) of the electric motor 11, the carrier frequency, and the total torque of all the electric motors 11 (11F, 11R) in state (v) of FIG. 8. In process P4, the frequency control unit 124 sends a control signal to the PWM control unit 125 before the relationship between the torque command TcR and the rotational speed ωR of the second electric motor 11R enters the switching region SA shown in FIG. 4 and satisfies the switching conditions. Cfc is output to lower the carrier frequency of the second electric motor 11R.

After that, in this process P4, the torque control unit 110, for example, decreases the torque command TcF of the first electric motor 11F, increases the torque command TcR of the second electric motor 11R, and maintains the total torque at a constant value. At this time, the torque control unit 110 increases the torque change rate limits ΔTrF and ΔTrR of the first electric motor 11F and the second electric motor 11R, for example.

Thereafter, the frequency control unit 124 outputs a control signal Cfc to the PWM control unit 125 when the torque command TcF of the first electric motor 11F has decreased to a torque T1q that can sufficiently suppress noise caused by carrier frequency switching. , lowers the carrier frequency of the first electric motor 11F. Thereby, noise caused by switching the carrier frequency of the first electric motor 11F can be suppressed.

For example, the torque control unit 110 reduces the torque change rate limit ΔTrF at a timing at which the carrier frequency of the first electric motor 11F is desired to be switched. Furthermore, for example, after decreasing the carrier frequency of the first electric motor 11F, the torque control unit 110 increases the torque command TcF to the maximum torque T1max, and maintains the torque command TcR of the second electric motor 11R at the maximum torque T2max.

Further, as shown in FIG. 8, the state (ii) in which it is necessary to lower the carrier frequency of some electric motors 11 of the vehicle 10 can be changed to state (vi) due to a further increase in the running load Lt of the vehicle 10, for example. After that, the state transitions to the state (iii) described above. State (vi) is, for example, a state in which the running load Lt of vehicle 10 is higher than state (ii), and it is necessary to switch carrier frequencies in all electric motors 11 in order to protect inverter 130.

When the electronic control device 100 executes the above-mentioned process P3 in this state (vi), the switching condition determination unit 123 determines that the respective torque commands TcF, TcR and rotational speeds ωF, ωR of the first electric motor 11F and the second electric motor 11R It is determined that the relationship enters the switching area SA shown in FIG. 4 after a predetermined period of time has passed and that the switching condition is satisfied (YES). Thereafter, the frequency control section 124 outputs this determination result DR to the PWM control section 125.

FIG. 14 is a graph showing an example of the torque command Tc (TcF, TcR) of the electric motor 11, the carrier frequency, and the total torque of all the electric motors 11 (11F, 11R) in state (vi) of FIG. 8. In process P4, the frequency control unit 124 sends a control signal to the PWM control unit 125 before the relationship between the torque command TcR and the rotational speed ωR of the second electric motor 11R enters the switching region SA shown in FIG. 4 and satisfies the switching conditions. Cfc is output to lower the carrier frequency of the second electric motor 11R.

More specifically, before the torque command TcR of the second electric motor 11R exceeds the torque T2q that can sufficiently suppress noise when the carrier frequency is switched, the frequency control unit 124 outputs a control signal Cfc to the PWM control unit 125 to lower the carrier frequency of the second electric motor 11R. This makes it possible to more reliably suppress noise caused by switching the carrier frequency of the second electric motor 11R.

Thereafter, when the torque command TcF of the first electric motor 11F decreases to a predetermined value capable of suppressing noise caused by carrier frequency switching, the electronic control device 100 sends a control signal Cfc from the frequency control unit 124 to the PWM control unit 125. is output to lower the carrier frequency of the first electric motor 11F. Thereby, noise caused by switching the carrier frequency of the first electric motor 11F can be suppressed.

For example, the torque control unit 110 reduces the torque change rate limit ΔTrF at a timing at which the carrier frequency of the first electric motor 11F is desired to be switched. Further, the torque control unit 110 increases the torque command TcF after decreasing the carrier frequency of the first electric motor 11F, and limits the torque command TcR of the second electric motor 11R to the maximum torque T2max or less, for example.

As described above, the electronic control device 100 of the present embodiment includes a switching condition storage section 122, a running load calculation section 121, a switching condition determining section 123, and a frequency control section 124, and has a The electric motor 11 is controlled. The switching condition storage unit 122 stores a switching area SA as a switching condition in which the rotational speed ω of the electric motor 11 is lower than a predetermined lower limit value ωl and the torque command Tc of the electric motor 11 is larger than a predetermined upper limit value Tch. The running load calculation unit 121 calculates the running load Lt of the vehicle 10 based on the rotational speed ω of the electric motor 11 and the torque command Tc. The switching condition determining unit 123 determines whether or not the switching condition is satisfied after a predetermined period of time has elapsed based on the running load Lt of the vehicle 10, the rotational speed ω of the electric motor 11, and the torque command Tc. When the switching condition determination unit 123 determines that the switching condition is satisfied, the frequency control unit 124 lowers the carrier frequency of the electric motor 11 when the torque command Tc of the electric motor 11 is equal to or lower than the upper limit value Tch.

With such a configuration, the electronic control device 100 of this embodiment can suppress the noise of the electric motor 11 when switching the carrier frequency. More specifically, in the electronic control device 100 of the present embodiment, the switching condition determination unit 123 can determine whether the electric motor 11 satisfies the switching condition after a predetermined period of time has elapsed. This switching condition corresponds to the switching area SA shown in FIG. A necessary condition is to lower the carrier frequency of . However, if the carrier frequency is lowered after the electric motor 11 satisfies the switching conditions, the carrier frequency will be switched while the torque command Tc of the electric motor 11 is high, which may generate noise. Therefore, in the electronic control device 100 of the present embodiment, when the switching condition determining unit 123 determines that the switching condition is satisfied after a predetermined time has elapsed, when the torque command Tc of the electric motor 11 is equal to or less than the predetermined upper limit value Tch, That is, before the switching conditions are satisfied, the carrier frequency of the electric motor 11 is lowered by the frequency control unit 124. As a result, the carrier frequency of the electric motor 11 can be lowered when the torque command Tc is lower than when the carrier frequency is lowered after the electric motor 11 satisfies the switching conditions, and the noise caused by switching the carrier frequency can be reduced. It becomes possible to suppress it.

Furthermore, in the electronic control device 100 of this embodiment, the electric motor 11 includes at least a first electric motor 11F and a second electric motor 11R. Further, the switching condition determination unit 123 determines whether the switching conditions are satisfied for each of the first electric motor 11F and the second electric motor 11R. Then, the frequency control unit 124 changes the carrier frequency of at least one of the first electric motor 11F and the second electric motor 11R, which has been determined by the switching condition determination unit 123 to satisfy the switching condition after a predetermined period of time, before the switching condition is satisfied. lower.

With such a configuration, according to the electronic control device 100 of the present embodiment, when the torque commands TcF and TcR of at least one of the first electric motor 11F and the second electric motor 11R are equal to or lower than the predetermined upper limit value Tch, the electric motor 11 carrier frequency can be lowered. Therefore, compared to the case where the carrier frequency is switched in a state where the torque command Tc of the electric motor 11 is higher than the upper limit value Tch, noise at the time of carrier frequency switching can be suppressed.

Furthermore, the electronic control device 100 of this embodiment includes a torque control section 110 that outputs torque commands TcF and TcR to the first electric motor 11F and the second electric motor 11R, respectively. For example, as shown in FIG. 12, the torque control unit 110 outputs the carrier frequency to one of the first electric motor 11F and the second electric motor 11R, which is not to be switched, for which the switching condition determining unit 123 has determined that the switching condition is not satisfied. The torque command Tc to be used is increased within a range below a predetermined upper limit value Tch. Further, the torque control unit 110 sets a torque command Tc to a predetermined value to be output to the other of the first electric motor 11F or the second electric motor 11R, which is the target of switching the carrier frequency determined by the switching condition determining unit 123 to satisfy the switching condition. lower to The frequency control unit 124 lowers the carrier frequency of the electric motor 11 to be switched when the torque control unit 110 reduces the torque command Tc output to the electric motor 11 to be switched to a predetermined value.

With such a configuration, the electronic control device 100 of this embodiment can prevent the electric motor 11 whose carrier frequency is not to be switched from satisfying the switching condition. Therefore, it is possible to suppress noise caused by switching the carrier frequency of the electric motor 11 that is not the carrier frequency switching target. Further, after reducing the torque command Tc output to the electric motor 11 whose carrier frequency is to be switched to a predetermined value, the carrier frequency of the electric motor 11 whose carrier frequency is to be switched is lowered. Therefore, noise caused by switching the carrier frequency of the electric motor 11 whose carrier frequency is to be switched with high torque can be suppressed.

Furthermore, in the electronic control device 100 of this embodiment, the torque control unit 110 reduces the torque command Tc output to the electric motor 11 to be switched to a predetermined value, for example, as shown in FIG. Thereafter, the torque control unit 110 may increase the torque command Tc to be output to the electric motor 11 to be switched, for example, when the torque command Tc to be output to the electric motor 11 to be switched has reached a predetermined upper limit value Tch. .

With such a configuration, the electronic control device 100 of the present embodiment can reduce the torque command Tc output to the electric motor 11 whose carrier frequency is to be switched to a predetermined value, thereby reducing the noise when switching the carrier frequency. Can be done. Furthermore, it is possible to suppress the torque command Tc to be lower than the upper limit value Tch in the electric motor 11 that is not the target of switching, thereby preventing the necessity of switching the carrier frequency. Furthermore, by suppressing the torque command Tc of the electric motor 11 that is not the target of switching, the insufficient torque can be compensated for by increasing the torque command Tc of the electric motor 11 after switching the carrier frequency.

Furthermore, the electronic control device 100 of this embodiment includes a torque control section 110 that outputs torque commands TcF and TcR to the first electric motor 11F and the second electric motor 11R, respectively. When the switching condition determining unit 123 determines that the first electric motor 11F and the second electric motor 11R satisfy the switching condition after a predetermined period of time has elapsed, the frequency control unit 124 controls the first electric motor 11F and the second electric motor 11R as shown in FIGS. Before one of the

electric motors

11F and 11R satisfies the switching condition, the carrier frequency of that one electric motor 11 is lowered. Further, after the frequency control unit 124 reduces the carrier frequency of the one electric motor 11, the torque control unit 110 increases the torque command Tc of the one electric motor 11, and also increases the torque command Tc of the one electric motor 11 and the first electric motor 11F and the second electric motor 11R. The torque command Tc of the other electric motor 11 is decreased to a predetermined value. Furthermore, the frequency control unit 124 reduces the carrier frequency of the other electric motor 11 when the torque control unit 110 reduces the torque command Tc of the other electric motor 11 to the predetermined value.

With this configuration, the electronic control device 100 of this embodiment can suppress noise by switching the carrier frequency of the one electric motor 11 when the torque command Tc of that electric motor 11 is lower than the upper limit value Tch. Furthermore, noise can be suppressed by lowering the torque command Tc of the other electric motor 11 to a predetermined value and then lowering the carrier frequency of that electric motor 11. In addition, when lowering the torque command Tc of the other electric motor 11, a decrease in the total torque can be suppressed by increasing the torque command Tc of the one electric motor 11 whose carrier frequency has been switched.

Furthermore, in the electronic control device 100 of the present embodiment, the torque control unit 110 reduces the torque command Tc of the other electric motor 11 to the predetermined value. Thereafter, when the relationship between the torque command Tc of the one electric motor 11 and the rotational speed ω reaches the upper limit of the operating range of the one electric motor 11, the torque control unit 110 controls the torque command Tc of the other electric motor 11. increase.

With such a configuration, according to the electronic control device 100 of the present embodiment, torque is distributed between the first electric motor 11F and the second electric motor 11R, and when the torque command Tc is lower than the upper limit value Tch, the carrier frequency is Noise can be suppressed by switching. Further, by distributing torque between the first electric motor 11F and the second electric motor 11R, it is possible to suppress a decrease in the total torque.

Although the embodiment of the electronic control device according to the present disclosure has been described above in detail using the drawings, the specific configuration is not limited to this embodiment, and design changes may be made within the scope of the gist of the present disclosure. etc., they are included in the present disclosure. For example, in the above-described embodiment, the electronic control device suppresses switching of the carrier frequency of the first electric motor close to the driver's seat of the vehicle by preferentially switching the carrier frequency of the second electric motor that is distant from the driver's seat of the vehicle. I explained an example. However, the electronic control device may preferentially switch the carrier frequency of the first electric motor that is closer to the driver's seat of the vehicle. Further, the electronic control device may include a machine learning unit that learns the driving tendency of the vehicle driver and updates information stored in the switching condition storage unit.

10 Vehicle 11 Electric motor 11F First electric motor 11R Second electric motor 100 Electronic control unit 110 Torque control unit 121 Running load calculation unit 122 Switching condition storage unit 123 Switching condition determining unit 124 Frequency control unit Lt Running load Tc Torque command TcF Torque command Tch Upper limit Value TcR Torque command ω Rotation speed ωF Rotation speed ωl Lower limit value ωR Rotation speed

Claims

An electronic control device that controls an electric motor for driving a vehicle,
a switching condition storage unit storing switching conditions in which the rotation speed of the electric motor is lower than a predetermined lower limit value and the torque command of the electric motor is higher than a predetermined upper limit value;
a running load calculation unit that calculates a running load of the vehicle based on the rotational speed and torque command of the electric motor;
a switching condition determining unit that determines whether or not the switching condition is satisfied after a predetermined period of time based on the running load of the vehicle and the rotational speed and torque command of the electric motor;
a frequency control unit that reduces the carrier frequency of the electric motor when the torque command of the electric motor is equal to or less than the upper limit value when the switching condition determination unit determines that the switching condition is satisfied;
An electronic control device comprising:
The electric motor includes at least a first electric motor and a second electric motor,
The switching condition determining unit determines whether the switching condition is satisfied for each of the first electric motor and the second electric motor,
The frequency control section controls the carrier frequency of at least one of the first electric motor and the second electric motor, which is determined by the switching condition determination section to satisfy the switching condition after a predetermined period of time, before the switching condition is satisfied. 2. The electronic control device according to claim 1, wherein the electronic control device lowers the power consumption.
a torque control unit that outputs a torque command to each of the first electric motor and the second electric motor,
The torque control unit is configured to output a torque command to one of the first electric motor and the second electric motor, which is not the carrier frequency switching target for which the switching condition is determined not to satisfy the switching condition by the switching condition determination unit, to be less than or equal to the upper limit value. and decreases to a predetermined value a torque command to be output to the other of the first electric motor or the second electric motor to which the carrier frequency determined by the switching condition determination unit satisfies the switching condition is to be switched. let me,
Claim characterized in that the frequency control unit reduces the carrier frequency of the electric motor to be switched when the torque control unit reduces the torque command output to the electric motor to be switched to the predetermined value. Item 2. Electronic control device according to item 2.
The torque control unit reduces the torque command output to the electric motor that is the switching target to the predetermined value, and then controls the switching when the torque command output to the electric motor that is not the switching target reaches the upper limit value. The electronic control device according to claim 3, wherein the electronic control device increases a torque command output to the target electric motor.
a torque control unit that outputs a torque command to each of the first electric motor and the second electric motor,
The frequency control unit is configured to select one of the first electric motor and the second electric motor when the switching condition determining unit determines that the first electric motor and the second electric motor satisfy the switching condition after a predetermined period of time has elapsed. before the one of the electric motors satisfies the switching condition, lowering the carrier frequency of the one of the electric motors,
The torque control unit increases the torque command of the one electric motor after the frequency control unit reduces the carrier frequency of the one electric motor, and increases the torque command of the one of the electric motors. reducing the torque command of the electric motor to a predetermined value;
3. The frequency control section lowers the carrier frequency of the other electric motor when the torque control section lowers the torque command of the other electric motor to the predetermined value. electronic control unit.
The torque control unit reduces the torque command of the other electric motor to the predetermined value, and then controls the relationship between the torque command and rotational speed of the one electric motor to reach an upper limit of the operating range of the one electric motor. 6. The electronic control device according to claim 5, wherein the torque command for the other electric motor is increased when the electric motor is turned off.