Electronic control device

Abstract

The invention provides an electronic control device capable of suppressing noise of a motor at the time of carrier frequency switching. An electronic control device for controlling an electric motor for driving a vehicle is provided with a switching condition storage unit (122), a driving load calculation unit (121), a switching condition determination unit (123), and a frequency control unit (124). A switching condition storage unit (122) stores switching conditions in which the rotational speed of the motor is lower than a predetermined lower limit value and the torque command of the motor is greater than a predetermined upper limit value. The travel load calculation unit (121) calculates the travel load (Lt) of the vehicle on the basis of the rotational speed (omega) of the motor and the torque command (Tc). A switching condition determination unit (123) determines, on the basis of a travel load (Lt) of a vehicle, a rotational speed (omega) of a motor, and a torque command (Tc), whether or not a switching condition is satisfied after a prescribed time has elapsed. When the switching condition determination unit (123) determines that the switching condition is satisfied, the frequency control unit (124) reduces the carrier frequency of the motor when the torque command of the motor is equal to or less than the upper limit value.

Description

Technical Field

[0001] The invention relates to an electronic control device for controlling an electric motor. Background Art

[0002] Inventions of power output devices for outputting driving power are known in the past (see Patent Document 1 below). The existing power output device includes, for example, a plurality of motors capable of outputting driving power, a plurality of drive circuits for driving the plurality of motors, a required power setting unit for setting the required power according to an operation of an operator, and a control unit for driving and controlling the plurality of drive circuits (Patent Document 1, paragraph 0006, claim 1, abstract, etc., below).

[0003] The plurality of drive circuits have a switch element, and the plurality of motors are driven respectively by switching the switch element. The control unit drives and controls the plurality of drive circuits in a manner that the plurality of motors output power based on the set required power when any of the plurality of drive circuits is in a normal state where any of the plurality of drive circuits can work normally. In addition, the control unit drives and controls the plurality of drive circuits as follows when any of the plurality of drive circuits is in an abnormal state where any of the plurality of drive circuits cannot work normally.

[0004] That is, the control unit controls the driving of 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 motor driven by the drive circuit in the abnormal state. More specifically, the control unit limits the power with higher priority than the switching frequency between the switching frequency and the power, and controls the driving of the plurality of drive circuits in such a manner that the power based on the set required power is output from the plurality of motors.

[0005] This conventional power output device can suppress the occurrence of noise caused by the switching of the switch element of the drive circuit in an abnormal state, while reducing the burden of the drive circuit in an abnormal state. As a result, it is possible to take into account both the good driving of the drive circuit and the suppression of the noise caused by the driving. In addition, regardless of whether any one of the multiple drive circuits is in a normal state, it is possible to cope with the required power (Paragraph 0007 of Patent Document 1).

[0006] Prior art literature

[0007] Patent Literature

[0008] Patent Document 1: Japanese Patent Application Publication No. 2006-197717 Summary of the invention

[0009] Problems to be solved by the invention

[0010] In the above-mentioned conventional power output device, for example, torque is distributed among a plurality of motors before the temperature of the drive circuit reaches the temperature limit, so the carrier frequency may be switched when the motor outputs high torque. Thus, when the carrier frequency is switched when the motor outputs high torque, there is a risk that the motor generates noise.

[0011] The present invention provides an electronic control device capable of suppressing the noise of a motor when a carrier frequency is switched.

[0012] Technical solutions to solve problems

[0013] One embodiment of the present invention is an electronic control device for controlling an electric motor for driving a vehicle, characterized in that it includes: a switching condition storage unit, which stores a switching condition that the rotation speed of the electric motor is lower than a specified lower limit value and the torque command of the electric motor is greater than a specified upper limit value; a driving load calculation unit, which calculates the driving load of the vehicle based on the rotation speed and torque command of the electric motor; a switching condition judgment unit, which judges whether the switching condition is satisfied after a specified time based on the driving load of the vehicle and the rotation speed and torque command of the electric motor; and a frequency control unit, which, when the switching condition judgment unit judges that the switching condition is satisfied, reduces the carrier frequency of the electric motor when the torque command of the electric motor is below the upper limit value.

[0014] Effects of the Invention

[0015] According to the above aspect of the present invention, it is possible to provide an electronic control device capable of suppressing noise of a motor when a carrier frequency is switched. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a block diagram showing an embodiment of an electronic control device according to the present invention.

[0017] Figure 2 It is composed Figure 1 Block diagram of the torque control unit of an electronic control device.

[0018] Figure 3 It is composed Figure 1 Block diagram of the three-phase current control section of an electronic control device.

[0019] Figure 4 It is a description of the composition Figure 3 A graph of the switching condition storage unit of the three-phase current control unit.

[0020] Figure 5 It is a description of the composition Figure 3 A graph of the switching condition storage unit of the three-phase current control unit.

[0021] Figure 6 It is composed Figure 3 Block diagram of the PWM control unit of the three-phase current control unit.

[0022] Figure 7 Yes Description Figure 1 Flowchart of the operation of the electronic control device.

[0023] Figure 8 yes Figure 1 State transition diagram of a vehicle under the control of an electronic control device.

[0024] Fig. 9 yes Figure 8 A graph showing the torque command of the motor in state (i).

[0025] Fig.10 yes Figure 8 A graph showing the torque command of the motor in state (ii).

[0026] Fig.11 yes Figure 8 A graph of the torque command of the motor under state (iii).

[0027] Fig.12 yes Figure 8 A graph of the torque command of the motor in state (iv).

[0028] Fig.13 yes Figure 8 A graph showing the torque command of the motor under state (v).

[0029] Fig.14 yes Figure 8 A graph showing the torque command of the motor in state (vi). DETAILED DESCRIPTION

[0030] Hereinafter, embodiments of the electronic control device according to the present invention will be described with reference to the drawings.

[0031] Figure 1 1 is a block diagram showing an embodiment of the electronic control device of the present invention. The electronic control device 100 of this embodiment is mounted in a vehicle 10 such as an electric vehicle, a hybrid vehicle, or a fuel cell vehicle, and is an electronic control device for controlling a motor 11 for driving the vehicle 10. Figure 1 Although not shown in the figure, the vehicle 10 includes, for example, a steering device, a braking device, a transmission device, a power storage device, and the like which are generally included in a normal vehicle.

[0032] Figure 1In the example shown, the vehicle 10 includes two motors 11 for driving, namely, a first motor 11F for driving left and right front wheels 13F via a gear 12F, and a second motor 11R for driving left and right rear wheels 13R via a gear 12R. In addition, the vehicle 10 includes, for example, an accelerator position sensor 14 for detecting the opening degree of an accelerator pedal, and an acceleration sensor 15 for detecting the acceleration of the vehicle 10 in the front-rear direction.

[0033] in addition, Figure 1 In the example shown, the vehicle 10 includes, for example, an ABS control unit 16 constituting an anti-lock braking system (ABS) and a TCS control unit 17 constituting a traction control system (TCS). Figure 1 Although not shown in the figure, the vehicle 10 has various sensors generally provided in a normal vehicle. In addition, the vehicle 10 only needs to have at least one motor 11 for driving, and may also have four or more motors 11 (in-wheel motors) for driving each wheel 13.

[0034] The electronic control device 100 is composed of, for example, a plurality of microcontrollers (not shown) and a plurality of electronic circuits including a plurality of electronic components. Each microcontroller constituting the electronic control device 100 has, for example, an input / output unit, a memory, a timer, and a central processing unit (CPU). The electronic control device 100 implements various functions described below by, for example, executing a program stored in the memory using the CPU.

[0035] Figure 1 In the example shown, the electronic control device 100 includes, for example, a torque control unit 110 and a three-phase current control unit 120. In addition, the electronic control device 100 may include, for example, an inverter 130. The electronic control device 100 includes, for example, a first three-phase current control unit 120F and a first inverter 130F for controlling the first motor 11F, and a second three-phase current control unit 120R and a second inverter 130R for controlling the second motor 11R. That is, one three-phase current control unit 120 and one inverter 130 are provided for each motor 11.

[0036] The torque control unit 110 receives an accelerator pedal operation amount Qac from, for example, the accelerator position sensor 14 and an acceleration α in the front-rear direction of the vehicle 10 from, for example, the acceleration sensor 15. The torque control unit 110 receives an anti-lock braking control signal Sab from, for example, the ABS control unit 16 and a traction control control signal Stc from, for example, the TCS control unit 17.

[0037] Furthermore, the torque control unit 110 receives the rotation speed ω of the electric motor 11 from, for example, the three-phase current control unit 120 . Figure 1In the illustrated example, the torque control unit 110 receives the rotation speed ωF of the first motor 11F from the first three-phase current control unit 120F and receives the rotation speed ωR of the second motor 11R from the second three-phase current control unit 120R.

[0038] The torque control unit 110 outputs a torque command Tc and a torque change rate limit ΔTr based on, for example, the input accelerator pedal operation amount Qac, the acceleration α of the vehicle 10, the rotation speed ω of the motor 11, and the control signals Sab, Stc, etc. More specifically, the torque control unit 110 outputs a torque command TcF and a torque change rate limit ΔTrF for the first motor 11F, and a torque command TcR and a torque change rate limit ΔTrR for the second motor 11R.

[0039] The three-phase current control unit 120 receives the torque command Tc and the torque change rate limit ΔTr for the motor 11 from the torque control unit 110. More specifically, the first three-phase current control unit 120F receives the torque command TcF and the torque change rate limit ΔTrF for the first motor 11F from the torque control unit 110. In addition, the second three-phase current control unit 120R receives the torque command TcR and the torque change rate limit ΔTrR for the second motor 11R from the torque control unit 110.

[0040] The three-phase current control unit 120 receives the rotation angle θ from the motor 11. More specifically, the first three-phase current control unit 120F receives the rotation angle θF from the first motor 11F, and the second three-phase current control unit 120R receives the rotation angle θR from the second motor 11R.

[0041] The three-phase current control unit 120 receives an inverter voltage Vin from the inverter 130. More specifically, the first three-phase current control unit 120F receives an inverter voltage VinF from the first inverter 130F, and the second three-phase current control unit 120R receives an inverter voltage VinR from the second inverter 130R.

[0042] 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 unit 120F and the second three-phase current control unit 120R receive three-phase currents Iu, Iv, and Iw from the first inverter 130F and the second inverter 130R, respectively.

[0043] The three-phase current control unit 120 outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz based on the above input. More specifically, the first three-phase current control unit 120F outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz to the first inverter 130F, and the second three-phase current control unit 120R outputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz to the second inverter 130R.

[0044] The inverter 130 is connected to the power supply voltage Vs, for example, and inputs gate signals Iu, Iv, Iw, Ix, Iy, and Iz from the three-phase current control unit 120. More specifically, the first inverter 130F and the second inverter 130R input gate signals Iu, Iv, Iw, Ix, Iy, and Iz from the first three-phase current control unit 120F and the second three-phase current control unit 120R, respectively.

[0045] Based on the above input, the inverter 130 outputs three-phase currents Iu, Iv, and Iw to the motor 11, and outputs an inverter voltage Vin to the three-phase current control unit 120. In more detail, the first inverter 130F and the second inverter 130R output three-phase currents Iu, Iv, and Iw to the first motor 11F and the second motor 11R, respectively. In addition, the first inverter 130F and the second inverter 130R output inverter voltages VinF and VinR to the first three-phase current control unit 120F and the second three-phase current control unit 120R, respectively.

[0046] Figure 2 It is composed Figure 1 1 is a block diagram of a torque control unit 110 of an electronic control device 100. The torque control unit 110 includes, for example, a required torque generation unit 111, a travel load calculation unit 112, a control torque generation unit 113, and a torque command generation unit 114.

[0047] The required torque generating unit 111 receives, for example, the accelerator pedal operation amount Qac and the rotation speed ω (ωF, ωR) of each motor 11. Based on these inputs, the required torque generating unit 111 calculates, for example, the total required torque RTT, the required torque RTF of the first motor 11F, and the required torque RTR of the second motor 11R, and outputs them to the torque command generating unit 114.

[0048] The running load calculation unit 112 receives, for example, the rotation speed ω (ωF, ωR) of each motor 11 and the acceleration α of the vehicle 10 as input. The running load calculation unit 112 estimates the running impedance value determined by the slope from the rotation speed ω of the motor 11 and the acceleration α of the vehicle 10. Furthermore, the running load calculation unit 112 calculates the running load Lt of the vehicle 10 using the estimated running impedance value and the front projection area of ​​the weight of the vehicle 10 stored in the memory, and outputs it to the torque command generation unit 114.

[0049] The control torque generating unit 113 receives, for example, a control signal Sab from the ABS control unit 16 and a control signal Stc from the TCS control unit 17. Based on these inputs, the control torque generating unit 113 calculates a control torque CT required for stabilizing the vehicle 10 such as antilock braking and traction control, and outputs the calculated control torque CT to the torque command generating unit 114.

[0050] The torque command generation unit 114 receives, for example, the total required torque RTT, the required torque RTF, and the required torque RTR from the required torque generation unit 111, and receives the rotation speed ω of each motor 11 from each three-phase current control unit 120. In addition, the torque command generation unit 114 receives the travel load Lt from the travel load calculation unit 112, and receives the control torque CT from the control torque generation unit 113. Based on these inputs, the torque command generation unit 114 calculates the torque command Tc (TcF, TcR) and the torque change rate limit ΔTr (ΔTrF, ΔTrR) of each motor 11, and outputs them to each three-phase current control unit 120.

[0051] Figure 3 It is composed Figure 1 The three-phase current control unit 120 of the electronic control device 100 is a block diagram. 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.

[0052] The running load calculation unit 121 takes as input, for example, the torque command Tc and the rotation speed ω of each motor 11, and estimates the running resistance value of the vehicle 10 determined by the slope. Furthermore, the running load calculation unit 121 calculates the running load Lt of the vehicle 10 based on the running resistance value, the weight of the vehicle 10, the rotation speed ω of each motor 11, and the front projection area of ​​the vehicle 10, and outputs it to the switching condition determination unit 123.

[0053] Figure 4 and Figure 5 It is described as Figure 3 1 is a graph of a switching condition storage unit 122 of a part of the three-phase current control unit 120. More specifically, Figure 4 The graph of represents the rotation speed ω of the motor 11 on the horizontal axis and the torque command Tc of the motor 11 on the vertical axis, and shows the operation section OA and the switching section SA of the motor 11 .

[0054] The switching interval SA is, for example, an interval in which the rotation speed ω of the motor 11 is below a predetermined lower limit ωl and the torque command Tc of the motor 11 is above a predetermined upper limit Tch. In this switching interval SA, the carrier frequency of the motor 11 needs to be reduced in order to protect the inverter 130. That is, Figure 4 The graph shown represents the switching conditions requiring switching of the carrier frequency as switching intervals SA.

[0055] However, when the relationship between the torque command Tc and the rotation speed ω of the motor 11 enters the switching interval SA, noise is generated when the carrier frequency of the motor 11 is switched. Therefore, it is necessary to avoid switching the carrier frequency of the motor 11 in the switching interval SA. That is, the switching interval SA is a restricted interval in which the switching of the carrier frequency should be restricted from the viewpoint of suppressing the noise of the motor 11.

[0056] in addition, Figure 5 The graph has the horizontal axis as the rotation speed ω of the motor 11 and the vertical axis as the torque command Tc of the motor 11, and shows the relationship between the torque command Tc of the motor 11 and the rotation speed ω for different driving loads Lt. Figure 5 As shown, the larger the running load Lt is, the larger the change in the torque command Tc with respect to the change in the rotation speed ω of the electric motor 11 is. Figure 4 and Figure 5 The graph is generated for each motor 11, is set and recorded in the switching condition storage unit 122, and is output from the switching condition storage unit 122 to the switching condition determination unit 123 as needed.

[0057] The switching condition determination unit 123 receives, for example, the torque command Tc, the torque change rate limit ΔTr, the rotation speed ω of each motor 11, and the running load Lt of the vehicle 10. The switching condition determination unit 123 obtains, for example, the switching condition storage unit 122 Figure 4 The operation interval OA and the switching interval SA of each motor 11 are shown, and Figure 5 The relationship between the torque command Tc and the rotation speed ω according to the travel load Lt is shown. The switching section SA indicates the switching condition that requires switching of the carrier frequency of the electric motor 11 as described above.

[0058] The switching condition determination unit 123 determines the switching condition based on the above input, Figure 4 The switching interval SA and Figure 5 The relationship shown in FIG. 1 is used to determine whether the relationship between the torque command Tc and the rotation speed ω of each motor 11 enters the switching interval SA after a predetermined time has passed. Whether the switching interval SA is entered is synonymous with whether the switching condition that requires the carrier frequency of the motor 11 to be reduced is satisfied. More specifically, the switching condition determination unit 123 determines whether the relationship between the torque command Tc and the rotation speed ω of each motor 11 enters the switching interval SA after a predetermined time has passed. Figure 4 and Figure 5The curves overlap, Figure 5 The Tc-ω curve enters Figure 4 When the switching interval SA is in the switching interval SA or is tangential thereto, it is determined that the relationship between the torque command Tc and the rotation speed ω of each motor 11 satisfies the switching condition after a predetermined time has passed.

[0059] The switching condition judgment unit 123 outputs a judgment result DR to the frequency control unit 124 as to whether the relationship between the torque command Tc and the rotation speed ω of the motor 11 enters the switching interval SA after a specified time, that is, whether the switching condition that the rotation speed ω is lower than the lower limit value ωl and the torque command Tc is greater than the upper limit value Tch is satisfied.

[0060] The frequency control unit 124 outputs a control signal Cfc for reducing the carrier frequency of the motor 11 to be controlled to the PWM control unit 125, for example, based on the determination result DR input from the switching condition determination unit 123. More specifically, the frequency control unit 124 outputs the control signal Cfc when the determination result DR is positive, that is, when it is determined that the relationship between the torque command Tc and the rotation speed ω of the motor 11 to be controlled satisfies the switching condition after a predetermined time has passed.

[0061] Figure 6 As Figure 3 The PWM control unit 125 is a block diagram of a part of the three-phase current control unit 120. The PWM control unit 125 receives the three-phase currents Iu, Iv, Iw, the rotation angle θ, and the torque command Tc of each motor 11, the inverter voltage Vin, and the control signal Cfc of the frequency control unit 124 as inputs, and outputs gate signals Iu, Iv, Iw, Ix, Iy, Iz and the rotation speed ω.

[0062] The PWM control unit 125 includes, 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. These units are general structures for vector control of the permanent magnet motor, i.e., the motor 11, so description thereof is omitted. The PWM control unit 125 reduces the carrier frequency of the power switching device in the inverter 130, for example, based on the control signal Cfc for reducing the carrier frequency of each motor 11.

[0063] Below, reference Figures 7 to 14 , the function of the electronic control device 100 of this embodiment is described. Figure 7 : is a flowchart explaining the operation of the electronic control device 100 . Figure 8 1 is a state transition diagram of the vehicle 10 under the control of the electronic control device 100 .

[0064] Figure 8The state (o) shown in the figure indicates, for example, a state in which the vehicle 10 is stopped, or a state in which the electronic control device 100 is not controlling the electric motor 11 (11F, 11R). From this state (o), for example, the electronic control device 100 starts controlling the electric motor 11, and when the vehicle 10 starts to travel, the vehicle 10 is transferred to, for example, Figure 8 In the state (i) shown, the electronic control device 100 executes Figure 7 The process P1 shown in FIG. 1 is a state (i) in which, for example, the running load Lt of the vehicle 10 is low and the carrier frequency of the electric motor 11 does not need to be switched.

[0065] Figure 7 In the process P1 shown, the accelerator pedal operation amount Qac, the acceleration α of the vehicle 10, and the control signals Sab and Stc of the ABS control unit 16 and the TCS control unit 17 are input to the torque control unit 110 of the electronic control device 100 as described above. 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 motor 11 as described above.

[0066] Next, the electronic control device 100 executes a process P2 for acquiring a switching condition. In the process P2, the switching condition determination unit 123 of the three-phase current control unit 120 constituting the electronic control device 100 acquires, for example, the switching condition of each motor 11 from the switching condition storage unit 122. Figure 4 The operation area OA and the switching area SA, and Figure 5 The relationship between the torque command Tc corresponding to the traveling load Lt and the rotation speed ω.

[0067] Next, the electronic control device 100 executes a process P3 for determining whether the switching condition is suitable. In the process P3, the torque command Tc, torque change rate limit ΔTr and rotation speed ω of each motor 11, and the running load Lt of the vehicle 10 are input to the switching condition determination unit 123 of the electronic control device 100 as described above. The switching condition determination unit 123 determines the switching condition based on these inputs and the torque change rate limit ΔTr and rotation speed ω of each motor 11, and the running load Lt of the vehicle 10, for example. Figure 4 and Figure 5 , and judge whether each motor 11 satisfies the switching condition after a specified time.

[0068] Fig. 9 Yes means Figure 8 Graph showing an example of the torque command Tc (TcF, TcR) of each motor 11 , the carrier frequency, and the total torque of all the motors 11 in the state (i) of the vehicle 10 . Fig. 9The graphs of the first and second torque commands TcF and TcR from the top show the maximum torques T1max and T2max of the first motor 11F and the second motor 11R, respectively, and the torques T1q and T2q that can sufficiently suppress noise when the carrier frequency is switched.

[0069] In the state (i) of the vehicle 10, since the running load Lt is relatively small, Figure 5 As shown in FIG. 1 , the change in the torque command Tc of each motor 11 relative to the change in the rotation speed ω is relatively small. As a result, the torque command Tc (TcF, TcR) of each motor 11 after a predetermined time has passed does not enter Figure 4 The switching section SA shown does not satisfy the switching condition after a predetermined time has passed.

[0070] In this case, Figure 7 In the process P3 shown, the switching condition determination unit 123 determines that the switching condition is not satisfied after the predetermined time (NO), and the electronic control device 100 does not execute the process P4 described later, but executes the process P5. In the process P5, the PWM control unit 125f of the PWM control unit 125 constituting the three-phase current control unit 120 outputs the control signal Cfc for reducing the carrier frequency and the gate signals Iu, Iv, Iw, Ix, Iy, Iz corresponding to the command voltages Vu*, Vv*, Vw*.

[0071] Here, the torque control unit 110 may, for example, set the relationship between the torque commands TcF and TcR of the first motor 11F and the second motor 11R and the rotation speeds ωF and ωR to be equal to or smaller than the relationship between the torque commands TcF and TcR of the first motor 11F and the second motor 11R. Figure 4 In the switching section SA shown, the torque distribution between the first electric motor 11F and the second electric motor 11R is performed.

[0072] The same is true when the vehicle 10 has four or more motors 11. That is, the torque control unit 110 can appropriately distribute the torque between the plurality of motors 11 in such a manner that the relationship between the torque command Tc and the rotation speed ω does not enter the switching interval SA and the carrier frequency does not need to be switched. In addition, in the process P5, the torque control unit 110 does not change the torque change rate limit ΔTr, for example.

[0073] Each inverter 130 outputs three-phase currents Iu, Iv, Iw to each motor 11 based on the input gate signals Iu, Iv, Iw, Ix, Iy, and Iz. As a result, each motor 11 rotates, and the left and right front wheels 13F and the left and right rear wheels 13R rotate via the gears 12F and 12R, so that the vehicle 10 travels. Then, the electronic control device 100, for example, Figure 7 The processing shown is completed and is repeatedly executed in a predetermined cycle.

[0074] For example, when the vehicle 10 starts to travel and the travel load Lt increases, such as when traveling uphill, the state of the vehicle 10 changes from Figure 8 The state (o) shown shifts to the state (ii). The state (ii) is, for example, a state in which the running load Lt of the vehicle 10 is higher than that of the state (i) and the carrier frequency needs to be switched in order to protect the inverter 130 in some of the plurality of motors 11 .

[0075] In the electronic control device 100 of the present embodiment, the state (ii) is, for example, a state in which the carrier frequency of the second motor 11R needs to be switched between the first motor 11F driving the front wheel 13F and the second motor 11R driving the rear wheel 13R. When the electronic control device 100 executes the above-mentioned process P3 in this state (ii), for example, Figure 5 As shown, the running load Lt of the vehicle 10 increases, and as a result, the change in the torque command Tc (TcR) of the second electric motor 11R relative to the change in the rotation speed ω (ωR) is larger than that in the above state (i).

[0076] As a result, the switching condition determination unit 123 determines, for example, in process P3 that the relationship between the torque command TcR and the rotation speed ωR of the second electric motor 11R enters the state of Figure 4 The switching interval SA shown satisfies the switching condition (YES). In addition, the switching condition determination unit 123 determines, for example, in process P3 that the relationship between the torque command TcF and the rotation speed ωF of the first motor 11F does not enter the state after a predetermined time has passed. Figure 4 The switching interval SA shown does not satisfy the switching condition (No). Thereafter, the frequency control unit 124 outputs the determination result DR of the process P3 to the PWM control unit 125 .

[0077] In the process P3, when the electronic control device 100 determines that at least one of the motors 11 satisfies the switching condition after the prescribed time has passed (Yes), the next process P4 is executed. In the process P4, the electronic control device 100 distributes the torques of the plurality of motors 11 and reduces the carrier frequency of the motor 11 that satisfies the switching condition after the prescribed time has passed.

[0078] Fig.10 Yes means Figure 8 Graph showing an example of the torque command Tc (TcF, TcR) of each motor 11 in the state (ii) of the vehicle 10 , the carrier frequency, and the total torque of all the motors 11 ( 11F, 11R). Fig.10 In the graph of the first and second torque commands TcF and TcR from the top, torques T1q and T2q are shown that can fully suppress noise when the carrier frequency is switched.

[0079] In the process P4, the electronic control device 100 outputs the control signal Cfc for reducing the carrier frequency from the frequency control unit 124 to the PWM control unit 125 in the second three-phase current control unit 120R for controlling the second motor 11R. Here, the frequency control unit 124 outputs the control signal Cfc to the PWM control unit 125 before the torque command TcR of the second motor 11R exceeds the torque T2q that can sufficiently suppress the noise when the carrier frequency is switched.

[0080] Results, such as Fig.10 As shown in the second graph from the top and the second graph from the bottom, before the torque command TcR of the second motor 11R exceeds the torque T2q, the carrier frequency of the second motor 11R is reduced to a predetermined frequency that can protect the inverter 130. Thus, the noise generated when the carrier frequency of the second motor 11R driving the rear wheels 13R of the vehicle 10 is reduced can be fully suppressed.

[0081] Furthermore, before the curve showing the relationship between the torque command TcR of the second motor 11R and the rotation speed ωR enters the switching interval SA, that is, when the torque command TcR of the second motor 11R is equal to or less than the upper limit value Tch, the carrier frequency of the second motor 11R is reduced, thereby achieving a noise suppression effect.

[0082] and then, Figure 7 In the process P4 shown, the electronic control device 100 distributes torque to the plurality of motors 11 using, for example, the torque control unit 110. More specifically, for example Figure 2 The torque command generating unit 114 shown distributes the torque commands TcF and TcR to the first motor 11F and the second motor 11R within a range where the carrier frequency of the first motor 11F does not need to be switched.

[0083] Fig.10 The graphs of the first and second torque commands TcF and TcR from the top of FIG. 1 show the maximum torques T1max and T2max of the first motor 11F and the second motor 11R, respectively, and the upper limits Tch of the torque commands TcF and TcR of the respective motors. The upper limit Tch is to make Figure 5 The curves showing the relationship between the torque command Tc and the rotation speed ω of the first electric motor 11F and the second electric motor 11R are not shown. Figure 4 The upper limit value Tch of the switching section SA is shown.

[0084] In the process P4, the torque control unit 110, for example, does not enter the torque command TcF of the first electric motor 11F driving the front wheels 13F of the vehicle 10. Figure 4The torque of the first motor 11F and the second motor 11R are distributed in the switching section SA shown. More specifically, the torque control unit 110 limits the torque command TcF of the first motor 11F to be equal to or less than the upper limit value Tch without reducing the carrier frequency.

[0085] In addition, the torque control unit 110 increases the torque command TcR of the second motor 11R with the carrier frequency reduced by exceeding the upper limit value Tch within the range not exceeding the maximum torque T2max. In addition, in the process P4, the torque control unit 110 reduces the torque change rate limit ΔTrR of the second motor 11R, for example, and does not change the torque change rate limit ΔTrF of the first motor 11F.

[0086] Afterwards, the electronic control device 100 executes the above-mentioned process P5, for example, Figure 7 Thus, the torque shortage caused by limiting the torque command TcF of the first motor 11F to be equal to or less than the upper limit value Tch is compensated by the torque of the second motor 11R, and the first motor 11F and the second motor 11R can output the required total torque.

[0087] In addition, when the vehicle 10 is traveling on a steep uphill slope and the travel load Lt increases greatly or when the vehicle 10 is accelerating suddenly, the state of the vehicle 10 changes from, for example, Figure 8 The state (o) shown shifts to the state (iii). The state (iii) is, for example, a state in which the running load Lt of the vehicle 10 is higher than that of the state (ii) and the carrier frequency needs to be switched in all the motors 11 in order to protect the inverter 130 .

[0088] In the electronic control device 100 of the present embodiment, the state (iii) is, for example, a state in which the carrier frequencies of the first motor 11F driving the front wheels 13F and the second motor 11R driving the rear wheels 13R need to be switched. 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, and thus, for example, Figure 5 As shown, the changes in the torque commands Tc (TcF, TcR) of the first motor 11F and the second motor 11R with respect to the changes in the rotation speeds ω (ωF, ωR) are greater than those in the state (ii).

[0089] As a result, the switching condition determination unit 123 determines, for example, in process P3 that the relationship between the torque commands TcF and TcR of the first motor 11F and the second motor 11R and the rotational speeds ωF and ωR respectively enters a state where the switching condition is the same as the state in which ... Figure 4 The switching interval SA shown satisfies the switching condition (Yes). Then, the frequency control unit 124 outputs the determination result DR to the PWM control unit 125 .

[0090] Then, the electronic control device 100 executes the next process P4 , for example. In the process P4 , the electronic control device 100 reduces the carrier frequencies of the first motor 11F and the second motor 11R, for example, to distribute torque between the first motor 11F and the second motor 11R when the switching condition is satisfied after a predetermined time.

[0091] Fig.11 Yes means Figure 8 Graph showing an example of the torque command Tc (TcF, TcR) of the motor 11 in the state (iii), the carrier frequency, and the total torque of all the motors 11 (11F, 11R). Fig.11 In the graph of the first and second torque commands TcF and TcR from the top, torques T1q and T2q are shown that can fully suppress noise when the carrier frequency is switched.

[0092] In the process P4, the electronic control device 100 outputs the control signal Cfc for reducing the carrier frequency from the frequency control unit 124 to the PWM control unit 125 in the three-phase current control unit 120 for controlling the first motor 11F and the second motor 11R, for example. Here, the frequency control unit 124 of each three-phase current control unit 120 outputs the control signal Cfc to the PWM control unit 125 before the torque instructions TcF and TcR of the first motor 11F and the second motor 11R exceed the torques T1q and T2q that can sufficiently suppress the noise when the carrier frequency is switched.

[0093] Results, such as Fig.11 As shown, before the torque commands TcF and TcR of the first motor 11F and the second motor 11R exceed the torques T1q and T2q, respectively, the carrier frequencies of the first motor 11F and the second motor 11R are reduced to a predetermined frequency capable of protecting the inverter 130. Thus, the noise generated when the carrier frequencies of the first motor 11F and the second motor 11R of the vehicle 10 are reduced can be sufficiently suppressed.

[0094] In addition, before the torque commands TcR of the first motor 11F and the second motor 11R exceed the upper limit value Tch and enter the switching interval SA, that is, before the switching condition is satisfied, the noise suppression effect can be obtained by reducing the carrier frequency of the first motor 11F and the second motor 11R. Furthermore, in the process P4, the electronic control device 100, for example, uses the torque control unit 110 to appropriately distribute the torque to the first motor 11F and the second motor 11R.

[0095] Afterwards, the electronic control device 100 executes the above-mentioned process P5, for example, Figure 7The processing shown ends. As described above, the electronic control device 100 reduces the carrier frequency of the first motor 11F and the second motor 11R in the state (iii) of the vehicle 10 before the torque commands TcF and TcR exceed the torques Tq1 and Tq2 or do not enter the upper limit value Tch of the switching interval SA. As a result, the noise generated when the carrier frequency of the first motor 11F and the second motor 11R of the vehicle 10 is reduced can be suppressed.

[0096] In addition, if Figure 8 As shown, the state (i) in which the running load Lt of the vehicle 10 is low and the carrier frequency of all the motors 11 does not need to be reduced is transferred to the above state (ii) through state (iv) due to, for example, an increase in the running load Lt of the vehicle 10. State (iv) is, for example, a state in which the running load Lt of the vehicle 10 is higher than that of state (i) and the carrier frequency needs to be switched in some of the plurality of motors 11 in order to protect the inverter 130.

[0097] In the electronic control device 100 of the present embodiment, the state (iv) is, for example, a state in which the carrier frequency of the second motor 11R needs to be switched between the first motor 11F driving the front wheel 13F and the second motor 11R driving the rear wheel 13R. When the electronic control device 100 executes the above-mentioned process P3 in the state (iv), the switching condition determination unit 123 determines whether the relationship between the torque command TcR and the rotation speed ωR of the second motor 11R enters the state after a predetermined time has passed. Figure 4 The switching interval SA shown satisfies the switching condition (Yes). Then, the frequency control unit 124 outputs the determination result DR to the PWM control unit 125 .

[0098] Thereafter, the electronic control device 100 executes, for example, the next process P4. In the process P4, the electronic control device 100 first distributes torque between the first motor 11F and the second motor 11R, and then reduces the carrier frequency of the second motor 11R.

[0099] Fig.12 Yes means Figure 8 Graph showing an example of the torque command Tc (TcF, TcR) of the motor 11 under state (iv), the carrier frequency, and the total torque of all the motors 11 (11F, 11R). In process P4, before the frequency control unit 124 reduces the carrier frequency of the second motor 11R, the torque control unit 110, for example, reduces the torque command TcR of the second motor 11R and increases the torque command TcF of the first motor 11F to maintain the total torque at a fixed value. At this time, the torque control unit 110, for example, increases the torque change rate limits ΔTrF, ΔTrR of the first motor 11F and the second motor 11R.

[0100] After that, when the torque command TcR of the second motor 11R decreases to a predetermined value that can suppress the noise caused by the carrier frequency switching, the frequency control unit 124 outputs a control signal Cfc to the PWM control unit 125 to reduce the carrier frequency of the second motor 11R. Thus, the noise caused by the carrier frequency switching of the second motor 11R can be suppressed.

[0101] The torque control unit 110, for example, reduces the torque change rate limit ΔTrR when the carrier frequency of the second motor 11R is to be switched. In addition, the torque control unit 110, for example, increases the torque command TcR of the second motor 11R after the frequency control unit 124 reduces the carrier frequency of the second motor 11R, and limits the torque command TcF of the first motor 11F to less than the upper limit value Tch entering the switching interval SA. As a result, it is not necessary to switch the carrier frequency of the first motor 11F, and it is possible to prevent the generation of noise when switching the carrier frequency at high torque.

[0102] In addition, if Figure 8 As shown, the state (i) in which the running load Lt of the vehicle 10 is low and the carrier frequency of all the motors 11 does not need to be reduced is transferred to the above-mentioned state (iii) through state (v) due to a sharp increase in the running load Lt of the vehicle 10. State (v) is, for example, a state in which the running load Lt of the vehicle 10 is higher than that of state (ii) and the carrier frequency needs to be switched in all the motors 11 in order to protect the inverter 130.

[0103] 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 relationship between the torque commands TcF and TcR of the first motor 11F and the second motor 11R and the rotation speeds ωF and ωR respectively enters the state after a predetermined time has passed. Figure 4 The switching interval SA shown satisfies the switching condition (Yes). The switching condition determination unit 123 outputs the determination result DR to the frequency control unit 124 .

[0104] Then, the electronic control device 100 executes the next process P4 , for example. In the process P4 , the electronic control device 100 first reduces the carrier frequency of the second motor 11R, then distributes torque between the first motor 11F and the second motor 11R, and then reduces the carrier frequency of the first motor 11F.

[0105] Fig.13 Yes means Figure 8 The torque command Tc (TcF, TcR) of the motor 11 in the state (v), the carrier frequency and the total torque of all the motors 11 (11F, 11R) are shown in the figure. In the process P4, the frequency control unit 124 enters the relationship between the torque command TcR and the rotation speed ωR of the second motor 11R. Figure 4Before the switching condition is satisfied in the switching interval SA shown, the control signal Cfc is output to the PWM control unit 125 to reduce the carrier frequency of the second electric motor 11R.

[0106] Then, in process P4, the torque control unit 110 reduces the torque command TcF of the first motor 11F and increases the torque command TcR of the second motor 11R to maintain the total torque at a fixed value. At this time, the torque control unit 110 increases the torque change rate limits ΔTrF and ΔTrR of the first motor 11F and the second motor 11R, for example.

[0107] After that, when the torque command TcF of the first motor 11F is reduced to the torque T1q that can sufficiently suppress the noise caused by the carrier frequency switching, the frequency control unit 124 outputs the control signal Cfc to the PWM control unit 125 to reduce the carrier frequency of the first motor 11F. Thus, the noise caused by the carrier frequency switching of the first motor 11F can be suppressed.

[0108] The torque control unit 110 reduces the torque change rate limit ΔTrF when the carrier frequency of the first motor 11F is to be switched, for example. In addition, after reducing the carrier frequency of the first 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 motor 11R at the maximum torque T2max.

[0109] In addition, if Figure 8 As shown, the state (ii) in which the carrier frequency of a part of the motors 11 of the vehicle 10 needs to be reduced is transferred to the above-mentioned state (iii) through the state (vi) due to a further increase in the running load Lt of the vehicle 10. State (vi) is, for example, a state in which the running load Lt of the vehicle 10 is higher than that of state (ii) and the carrier frequency of all the motors 11 needs to be switched in order to protect the inverter 130.

[0110] 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 relationship between the torque commands TcF, TcR and the rotation speeds ωF, ωR of the first motor 11F and the second motor 11R respectively enters the state after a predetermined time has passed. Figure 4 The switching interval SA shown satisfies the switching condition (Yes). Then, the frequency control unit 124 outputs the determination result DR to the PWM control unit 125 .

[0111] Then, the electronic control device 100 executes the next process P4 , for example. In the process P4 , the electronic control device 100 first reduces the carrier frequency of the second motor 11R, then distributes torque between the first motor 11F and the second motor 11R, and then reduces the carrier frequency of the first motor 11F.

[0112] Fig.14 Yes means Figure 8 The torque command Tc (TcF, TcR) of the motor 11, the carrier frequency, and the total torque of all the motors 11 (11F, 11R) in the state (vi) are shown in the figure. In the process P4, the frequency control unit 124 enters the relationship between the torque command TcR and the rotation speed ωR of the second motor 11R. Figure 4 Before the switching condition is satisfied in the switching interval SA shown, the control signal Cfc is output to the PWM control unit 125 to reduce the carrier frequency of the second electric motor 11R.

[0113] More specifically, the frequency control unit 124 outputs the control signal Cfc to the PWM control unit 125 to reduce the carrier frequency of the second motor 11R before the torque command TcR of the second motor 11R exceeds the torque T2q that can sufficiently suppress the noise during the carrier frequency switching. This can more reliably suppress the noise caused by the carrier frequency switching of the second motor 11R.

[0114] Then, in process P4, the torque control unit 110 reduces the torque command TcF of the first motor 11F and increases the torque command TcR of the second motor 11R to maintain the total torque at a fixed value. At this time, the torque control unit 110 increases the torque change rate limits ΔTrF and ΔTrR of the first motor 11F and the second motor 11R, for example.

[0115] Afterwards, when the torque command TcF of the first motor 11F is reduced to a predetermined value that can suppress the noise caused by the carrier frequency switching, the electronic control unit 100 outputs a control signal Cfc from the frequency control unit 124 to the PWM control unit 125 to reduce the carrier frequency of the first motor 11F. Thus, the noise caused by the carrier frequency switching of the first motor 11F can be suppressed.

[0116] The torque control unit 110 reduces the torque change rate limit ΔTrF when the carrier frequency of the first motor 11F is to be switched. The torque control unit 110 increases the torque command TcF after reducing the carrier frequency of the first motor 11F and limits the torque command TcR of the second motor 11R to less than the maximum torque T2max.

[0117] As described above, the electronic control device 100 of the present embodiment includes the switching condition storage unit 122, the running load calculation unit 121, the switching condition determination unit 123, and the frequency control unit 124, and controls the motor 11 for running of the vehicle 10. The switching condition storage unit 122 stores the switching interval SA as the switching condition that the rotation speed ω of the motor 11 is lower than the prescribed lower limit value ωl and the torque command Tc of the motor 11 is greater than the prescribed upper limit value Tch. The running load calculation unit 121 calculates the running load Lt of the vehicle 10 based on the rotation speed ω of the motor 11 and the torque command Tc. The switching condition determination unit 123 determines whether the switching condition is satisfied after a prescribed time has passed based on the running load Lt of the vehicle 10 and the rotation speed ω and the torque command Tc of the motor 11. When the switching condition determination unit 123 determines that the switching condition is satisfied, the frequency control unit 124 reduces the carrier frequency of the motor 11 when the torque command Tc of the motor 11 is below the upper limit value Tch.

[0118] With such a structure, the electronic control device 100 of this embodiment can suppress the noise of the motor 11 when the carrier frequency is switched. More specifically, the electronic control device 100 of this embodiment can use the switching condition determination unit 123 to determine whether the motor 11 satisfies the switching condition after a predetermined time has passed. The switching condition corresponds to Figure 4 The switching interval SA shown is a condition in which the rotation speed ω of the motor 11 is lower than the specified lower limit ωl, and the torque command Tc of the motor 11 is greater than the specified upper limit Tch, and the carrier frequency of the motor 11 needs to be reduced. However, when the carrier frequency is reduced after the motor 11 satisfies the switching condition, the carrier frequency is switched in a state where the torque command Tc of the motor 11 is high, and there is a risk of generating noise. Therefore, in the electronic control device 100 of the present embodiment, when the switching condition judgment unit 123 judges that the switching condition is satisfied after a specified time, when the torque command Tc of the motor 11 is below the specified upper limit Tch, that is, before the switching condition is satisfied, the carrier frequency of the motor 11 is reduced by the frequency control unit 124. As a result, compared with the case in which the carrier frequency is reduced after the motor 11 satisfies the switching condition, the carrier frequency of the motor 11 can be reduced at a lower torque command Tc, and the noise caused by the carrier frequency switching can be suppressed.

[0119] In the electronic control device 100 of the present embodiment, the motor 11 includes at least a first motor 11F and a second motor 11R. The switching condition determination unit 123 determines whether the switching condition is satisfied for each of the first motor 11F and the second motor 11R. The frequency control unit 124 reduces the carrier frequency of at least one of the first motor 11F and the second motor 11R, which is determined by the switching condition determination unit 123 to satisfy the switching condition after a predetermined time, before the switching condition is satisfied.

[0120] With such a configuration, the electronic control device 100 of the present embodiment can reduce the carrier frequency of the motor 11 when the torque command TcF, TcR of at least one of the first motor 11F and the second motor 11R is below the predetermined upper limit value Tch. Thus, compared with the case where the carrier frequency is switched when the torque command Tc of the motor 11 is higher than the upper limit value Tch, noise when the carrier frequency is switched can be suppressed.

[0121] The electronic control device 100 of the present embodiment includes a torque control unit 110 that outputs torque commands TcF and TcR to the first electric motor 11F and the second electric motor 11R, respectively. The torque control unit 110 is, for example, Fig.12 As shown, the torque control unit 110 increases the torque command Tc to be output to one of the first motor 11F and the second motor 11R, which are not the carrier frequency switching targets and are determined by the switching condition determination unit 123 to not satisfy the switching condition, within a range below the prescribed upper limit value Tch. In addition, the torque control unit 110 reduces the torque command Tc to be output to the other of the first motor 11F and the second motor 11R, which are the carrier frequency switching targets and are determined by the switching condition determination unit 123 to satisfy the switching condition, to a prescribed value. When the torque control unit 110 reduces the torque command Tc output to the switching target motor 11 to a prescribed value, the frequency control unit 124 reduces the carrier frequency of the switching target motor 11.

[0122] With such a structure, according to the electronic control device 100 of this embodiment, it is possible to prevent the motor 11 that is not the target of the carrier frequency switching from satisfying the switching condition. Thus, it is possible to suppress the noise caused by the carrier frequency switching of the motor 11 that is not the target of the carrier frequency switching. In addition, after the torque command Tc output to the motor 11 that is the target of the carrier frequency switching is reduced to a predetermined value, the carrier frequency of the motor 11 that is the target of the switching is reduced. Thus, it is possible to suppress the noise caused by the carrier frequency of the motor 11 that is the target of the carrier frequency switching under high torque.

[0123] In the electronic control device 100 of the present embodiment, the torque control unit 110 is, for example, Fig.12 As shown, the torque command Tc output to the switching target motor 11 is reduced to a predetermined value. Thereafter, the torque control unit 110 may increase the torque command Tc output to the switching target motor 11, for example, when the torque command Tc output to the non-switching target motor 11 reaches a predetermined upper limit value Tch.

[0124] With such a structure, according to the electronic control device 100 of this embodiment, the torque command Tc output to the motor 11 of the carrier frequency switching object can be reduced to a predetermined value, thereby reducing the noise when the carrier frequency is switched. In addition, the torque command Tc can be suppressed below the upper limit value Tch in the motor 11 that is not the switching object, thereby preventing the need to switch the carrier frequency. Furthermore, the insufficient torque due to the suppression of the torque command Tc of the motor 11 that is not the switching object can be compensated by increasing the torque command Tc of the motor 11 after the carrier frequency is switched.

[0125] In addition, the electronic control device 100 of the present embodiment includes a torque control unit 110 that outputs torque commands TcF and TcR to the first motor 11F and the second motor 11R, respectively. When the switching condition determination unit 123 determines that the first motor 11F and the second motor 11R satisfy the switching condition after a predetermined time has passed, the frequency control unit 124 Fig.13 and Fig.14 As shown, before one of the first motor 11F and the second motor 11R satisfies the switching condition, the carrier frequency of the one motor 11 is reduced. In addition, after the frequency control unit 124 reduces the carrier frequency of the one motor 11, the torque control unit 110 increases the torque command Tc of the one motor 11 and reduces the torque command Tc of the other motor 11 of the first motor 11F and the second motor 11R to a specified value. Furthermore, the frequency control unit 124 reduces the carrier frequency of the other motor 11 when the torque control unit 110 reduces the torque command Tc of the other motor 11 to the specified value.

[0126] With such a structure, according to the electronic control device 100 of this embodiment, the carrier frequency of the above-mentioned one motor 11 can be switched when the torque command Tc of the motor 11 is lower than the upper limit value Tch, thereby suppressing noise. Furthermore, after the torque command Tc of the above-mentioned other motor 11 is reduced to a predetermined value, the carrier frequency of the motor 11 is reduced, thereby suppressing noise. In addition, when the torque command Tc of the above-mentioned other motor 11 is reduced, the torque command Tc of the above-mentioned one motor 11 whose carrier frequency is switched is increased, thereby suppressing the reduction of the total torque.

[0127] In addition, in the electronic control device 100 of the present embodiment, the torque control unit 110 reduces the torque command Tc of the other motor 11 to the above-mentioned predetermined value. Thereafter, when the relationship between the torque command Tc of the one motor 11 and the rotation speed ω reaches the upper limit of the operating range of the one motor 11, the torque control unit 110 increases the torque command Tc of the other motor 11.

[0128] With such a configuration, the electronic control device 100 of this embodiment can distribute torque between the first motor 11F and the second motor 11R, switch the carrier frequency when the torque command Tc is lower than the upper limit value Tch, and suppress noise. In addition, it is possible to distribute torque between the first motor 11F and the second motor 11R and suppress a decrease in total torque.

[0129] The above embodiment of the electronic control device of the present invention is described in detail using the accompanying drawings, but the specific structure is not limited to the embodiment, and even if a design change occurs within the scope of the main purpose of the present invention, it is also included in the present invention. For example, in the above embodiment, an example is described in which the electronic control device suppresses the switching of the carrier frequency of the first motor close to the driver's seat of the vehicle by preferentially switching the carrier frequency of the second motor away from the driver's seat of the vehicle. However, the electronic control device may also preferentially switch the carrier frequency of the first motor close to the driver's seat of the vehicle. In addition, the electronic control device may also have a machine learning unit that learns the driving tendency of the driver of the vehicle and updates the information stored in the switching condition storage unit.

[0130] Description of Reference Numerals

[0131] 10 Vehicles

[0132] 11 Electric Motor

[0133] 11F First Motor

[0134] 11R Second motor

[0135] 100 Electronic Control Devices

[0136] 110 Torque control unit

[0137] 121 Driving load calculation unit

[0138] 122 Switching condition storage unit

[0139] 123 Switching condition judgment unit

[0140] 124 Frequency Control Unit

[0141] Lt Travel Load

[0142] Tc torque command

[0143] TcF torque command

[0144] Tch upper limit value

[0145] TcR torque command

[0146] ω Rotation speed

[0147] ωF Rotation speed

[0148] ωl lower limit

[0149] ωR rotation speed.

Claims

1. An electronic control device for controlling an electric motor for driving a vehicle, characterized in that: include: a switching condition storage unit storing a switching condition that a rotation speed of the motor is lower than a prescribed lower limit value and a torque command of the motor is higher than a prescribed upper limit value; a running load calculation unit that calculates a running load of the vehicle based on a rotation speed and a torque command of the electric motor; a switching condition determination unit that determines whether the switching condition is satisfied after a predetermined time has passed based on the running load of the vehicle and the rotation speed and torque command of the motor; and A frequency control unit that, when the switching condition determination unit determines that the switching condition is satisfied, reduces a carrier frequency of the motor when a torque command of the motor is equal to or less than an upper limit value.

2. The electronic control device according to claim 1, characterized in that: The electric motor comprises at least a first electric motor and a second electric motor, The switching condition determination unit determines whether the switching condition is satisfied for each of the first motor and the second motor. The frequency control unit reduces the carrier frequency of at least one of the first motor and the second motor determined by the switching condition determination unit to satisfy the switching condition after a predetermined time has elapsed, before the switching condition is satisfied.

3. The electronic control device according to claim 2, characterized in that: A torque control unit is provided for outputting torque commands to the first motor and the second motor respectively. The torque control unit increases the torque command to be output to one of the first motor and the second motor that is not the carrier frequency switching object determined by the switching condition determination unit as not satisfying the switching condition within a range below the upper limit value, and reduces the torque command to be output to the other of the first motor and the second motor that is the carrier frequency switching object determined by the switching condition determination unit as satisfying the switching condition to a specified value, The frequency control unit reduces the carrier frequency of the electric motor as the switching target when the torque control unit reduces the torque command to be output to the electric motor as the switching target to the predetermined value.

4. The electronic control device according to claim 3, characterized in that: After the torque control unit reduces the torque command to be output to the electric motor of the switching object to the specified value, when the torque command to be output to the electric motor that is not the switching object reaches the upper limit value, the torque control unit increases the torque command to be output to the electric motor of the switching object.

5. The electronic control device according to claim 2, characterized in that: A torque control unit is provided for outputting torque commands to the first motor and the second motor respectively. The frequency control unit, when the switching condition determination unit determines that the first motor and the second motor satisfy the switching condition after a predetermined time has passed, reduces the carrier frequency of the one of the first motor and the second motor before the one of the first motor and the second motor satisfies the switching condition, the torque control unit increases the torque command of the one motor after the frequency control unit reduces the carrier frequency of the one motor, and reduces the torque command of the other motor of the first motor and the second motor to a prescribed value, The frequency control unit reduces the carrier frequency of the other electric motor when the torque control unit reduces the torque command of the other electric motor to the predetermined value.

6. The electronic control device according to claim 5, characterized in that: The torque control unit increases the torque command of the other motor when the relationship between the torque command and the rotation speed of the one motor reaches an upper limit of the operating range of the one motor after reducing the torque command of the other motor to the predetermined value.

Images