Vehicle control device

Abstract

To prompt operation manipulation such as accelerator operation to an operator when a motor for travel is in a motor lock state.SOLUTION: A control device for a vehicle includes a torque setting unit which sets a first torque command value of a motor for travel on the basis of an accelerator operation amount, a torque correction unit which feedbacks a control result of the motor for travel to the first torque command value and corrects the first torque command value to a second torque command value restraining vibration of a drive system and an inverter control unit which generates a drive signal of a switching element on the basis of the second torque command value and a carrier signal. The torque correction unit, if it is determined that the motor for travel is in a motor lock state, sets feedback gain for correcting the first torque command value to the second torque command value, to a value smaller than a threshold value (S18). The inverter control unit, if it is determined that the motor for travel is in the motor lock state, sets frequency of the carrier signal for generating a drive signal, to a value smaller than the threshold value (S18).SELECTED DRAWING: Figure 7

Description

[Technical field]

[0001] The present invention relates to a vehicle control device that controls a driving motor that is a power source for a drive train. [Background technology]

[0002] Vehicles such as electric vehicles and hybrid vehicles are equipped with a traction motor as a power source for the drive system. Furthermore, power is supplied to the stator coil of the traction motor from a lithium ion battery or the like via an inverter (see Patent Documents 1 to 4). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 9-70195 [Patent Document 2] JP 2020-5373 A [Patent Document 3] JP 2007-325417 A [Patent Document 4] JP 2017-220971 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the driving motor is in a motor lock state where it operates in a lock region with high torque and low revolutions, there is a risk of the current flowing through the stator coil increasing locally. In this motor lock state, the temperature of the driving motor increases locally, so the driver is required to release the motor lock state by operating the accelerator or other driving operations. An object of the present invention is to prompt a driver to perform driving operations such as accelerator operation when a driving motor is in a motor lock state. [Means for solving the problem]

[0005] The present invention provides a vehicle control device for controlling a driving motor which is a power source for a drive train, the vehicle control device including an inverter having a plurality of switching elements for supplying power to the driving motor. The vehicle control device includes: a torque setting unit that sets a first torque command value for the driving motor based on an accelerator operation amount; The vehicle control device includes: a torque correction unit that feeds back a control result of the driving motor to the first torque command value and corrects the first torque command value to a second torque command value that suppresses vibration in the drive system; The vehicle control device includes: an inverter control unit that generates a drive signal for the switching element based on the second torque command value and a carrier signal; The vehicle control device includes: a motor lock determination unit that determines whether the running motor is in a motor lock state in which the running motor operates in a lock region; has. The torque correction unit determines that the driving motor is in a motor lock state. And the road gradient is determined to be an uphill gradient. a feedback gain for correcting the first torque command value to the second torque command value is set to be smaller than a threshold value. do. The inverter control unit determines that the driving motor is in a motor lock state. And the road gradient is determined to be an uphill gradient. In this case, the frequency of the carrier signal when generating the drive signal is set lower than a threshold value. Effect of the Invention

[0006] According to the present invention, when it is determined that the traveling motor is in a motor lock state, the torque correction unit sets the feedback gain when correcting the first torque command value to the second torque command value to be smaller than a threshold value, and when it is determined that the traveling motor is in a motor lock state, the inverter control unit sets the frequency of the carrier signal when generating a drive signal to be lower than a threshold value. As a result, when the traveling motor is in a motor lock state, the drive system is vibrated to prompt the driver to perform driving operations such as accelerator operation. [Brief description of the drawings]

[0007] [Figure 1]1 is a diagram showing an example of the configuration of a vehicle equipped with a vehicle control device according to an embodiment of the present invention; [Diagram 2] FIG. 4 is a diagram showing an example of a torque map used when setting a target torque command value. [Diagram 3] FIG. 2 is a diagram illustrating an example of an inverter and a motor controller. [Figure 4] FIG. 4 is a diagram illustrating a configuration example of a command value correction unit that executes vibration suppression control; [Diagram 5] FIG. 13 illustrates an example of a lock area. [Figure 6] 10 is a flowchart showing an example of a procedure for executing lock release control. [Figure 7] 10 is a flowchart showing an example of a procedure for executing lock release control. [Figure 8] FIG. 4 is a diagram showing a transition of the operating state of a driving motor. [Figure 9] 13(A) and (B) are diagrams showing changes in energizing current due to carrier frequency. [Figure 10] FIG. 13 is a diagram showing another example of a lock region. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0009] [Vehicle configuration] FIG. 1 is a diagram showing an example of the configuration of a vehicle 11 equipped with a vehicle control device 10 according to an embodiment of the present invention. As shown in FIG. 1, a drive system 12 of the vehicle 11 is provided with a driving motor 13 as a power source. The driving motor 13 shown in the figure is a three-phase AC motor such as a synchronous motor or an induction motor. A rotor 14 of the driving motor 13 is connected to wheels 18 via a motor output shaft 15, a differential mechanism 16, and a wheel drive shaft 17. An inverter 20 is connected to a stator 19 of the driving motor 13, and a battery 21 such as a lithium-ion battery is connected to the inverter 20. Furthermore, the driving motor 13 is provided with a rotation sensor 22 such as a resolver that detects the rotation speed from the rotation angle of the rotor 14.

[0010] The vehicle 11 is also provided with an electrohydraulic brake 30 that brakes the wheels 18. The electrohydraulic brake 30 has a master cylinder 33 to which a brake pedal 31 is connected and to which an electric motor 32 is attached. The electrohydraulic brake 30 also has a caliper 35 that brakes a disc rotor 34 of the wheel 18, and a hydraulic circuit unit 36 ​​that controls the brake hydraulic pressure supplied to each caliper 35. When the master cylinder 33 is pressed by depressing the brake pedal 31, or when the master cylinder 33 is pressed by the electric motor 32, the brake hydraulic pressure is transmitted from the master cylinder 33 through the hydraulic circuit unit 36 ​​to the caliper 35, and the disc rotor 34 of the wheel 18 is braked by the caliper 35.

[0011] [Main Controller] As shown in FIG. 1, the vehicle control device 10 is provided with a main controller 40 including a microcomputer and the like. The main controller 40 has a target torque setting unit (torque setting unit) 41, a brake control unit 42, and a meter control unit 43. The target torque setting unit 41 sets a target torque command value (first torque command value) Tm1 for the traveling motor 13 based on the accelerator operation of the driver and the like. The brake control unit 42 controls the electric hydraulic brake 30 according to the driving conditions and the like, and the meter control unit 43 controls the display information of the meter panel 44 according to the driving conditions and the like. The main controller 40 is also connected to an accelerator sensor 46 that detects the depression amount of an accelerator pedal 45 (hereinafter, referred to as accelerator operation amount Acc), a brake sensor 47 that detects the depression amount of a brake pedal 31, a vehicle speed sensor 48 that detects the driving speed of the vehicle 11, and a gradient sensor 49 that detects the road gradient. An acceleration sensor can be used as the gradient sensor 49.

[0012] FIG. 2 is a diagram showing an example of a torque map used when setting the target torque command value Tm1. As shown in FIG. 2, characteristic lines L1 to L4 indicating the target torque command value Tm1 for each accelerator operation amount Acc are set in the torque map. That is, when the accelerator operation amount Acc is 0%, the target torque command value Tm1 is set along the characteristic line L1, and when the accelerator operation amount Acc is 25%, the target torque command value Tm1 is set along the characteristic line L2. Similarly, when the accelerator operation amount Acc is 50%, the target torque command value Tm1 is set along the characteristic line L3, and when the accelerator operation amount Acc is 100%, the target torque command value Tm1 is set along the characteristic line L4. For example, when the accelerator operation amount Acc is "50%" and the rotation speed ωm of the rotor 14 is "Sa", "Ta" is set as the target torque command value Tm1. In addition, in the torque map shown in FIG. 2, four characteristic lines L1 to L4 are set as an example, but the present invention is not limited to this, and the torque map may have five or more characteristic lines set.

[0013] [Motor controller] As shown in Fig. 1, the vehicle control device 10 is provided with a motor controller 50 consisting of a microcomputer or the like in order to control the driving motor 13 via the inverter 20. The motor controller 50 and the main controller 40 are connected to each other so as to be able to communicate with each other via an in-vehicle network 51 such as a CAN. Fig. 3 is a diagram showing an example of the inverter 20 and the motor controller 50.

[0014] As shown in Fig. 3, the inverter 20 is provided with a three-phase bridge circuit having a plurality of switching elements SW1 to SW6 in order to supply power to the traveling motor 13. These switching elements SW1 to SW6 are driven by pulse width modulation control, i.e., PWM control, and DC power from the battery 21 is converted to AC power via the switching elements SW1 to SW6. The AC power output from the inverter 20 is then supplied to the field coils Cu, Cv, and Cw of each phase (U phase, V phase, and W phase) that constitute the stator coil 52 of the traveling motor 13. In this way, by supplying AC power to the field coils Cu, Cv, and Cw of the traveling motor 13, a rotating magnetic field can be generated in the stator 19 to rotate the rotor 14.

[0015] As shown in FIG. 3, the motor controller 50 has a command value correction unit (torque correction unit) 53 and an inverter control unit 54. The command value correction unit 53 corrects the target torque command value Tm1 to a vibration-damping torque command value (second torque command value) Tm2 in order to suppress vibration of the drive system 12 by vibration-damping control, which will be described later. The inverter control unit 54 is composed of a carrier output unit 55, a duty output unit 56, a pulse setting unit 57, and a gate drive unit 58. The carrier output unit 55 outputs a carrier signal Sc of a predetermined frequency, and the duty output unit 56 outputs command duties Du, Dv, and Dw of each phase that are set based on the vibration-damping torque command value Tm2. The pulse setting unit 57 compares the carrier signal Sc output from the carrier output unit 55 with the command duties Du, Dv, and Dw output from the duty output unit 56, and sets pulse signals Pu, Pv, and Pw that are drive signals for the switching elements SW1 to SW6. The gate driver 58 drives the switching elements SW1 to SW6 based on the pulse signals Pu, Pv, and Pw. The duty output unit 56 receives the energizing currents of the field coils Cu, Cv, and Cw from the current sensor 59 and the rotation angle of the rotor 14 from the rotation sensor 22 in order to set the command duties Du, Dv, and Dw.

[0016] [Vibration control] Next, the vibration damping control of the traveling motor 13 by the motor controller 50 will be described. The vibration damping control of the traveling motor 13 is torque control of the traveling motor 13 that is executed to suppress torsional vibration of the wheel drive shaft 17 that constitutes the drive system 12. Here, FIG. 4 is a diagram showing an example of the configuration of the command value correction unit 53 that executes the vibration damping control. The motor system 60 shown in FIG. 4 is a control system made up of the inverter control unit 54, the inverter 20, and the traveling motor 13.

[0017] 4, in order to execute vibration suppression control of the traveling motor 13, the command value correction unit 53 of the motor controller 50 is provided with a feedforward processing unit 61 and a feedback processing unit 62. The feedforward processing unit 61 executes feedforward processing for attenuating the resonance component of the wheel drive shaft 17 with respect to the target torque command value Tm1 received from the main controller 40. Then, the feedback processing unit 62 feeds back the rotation speed ωm of the rotor 14, which is the control result of the traveling motor 13, with respect to the target torque command value Tm1 that has been subjected to the feedforward processing, and corrects the target torque command value Tm1 to a vibration suppression torque command value Tm2 so as to cancel out the vibration of the wheel drive shaft 17.

[0018] The feedback processor 62 is composed of a filter processor 63, a torque converter 64, and a gain processor 65. The filter processor 63 extracts the resonance component ω1 of the wheel drive shaft 17 from the rotation speed ωm by performing a predetermined filter process on the rotation speed ωm. Next, the torque converter 64 performs a predetermined conversion process on the resonance component ω1 of the rotation speed ωm to convert the resonance component ω1 of the rotation speed ωm into a resonance component t1 of the motor torque. Furthermore, the gain processor 65 multiplies the resonance component t1 of the motor torque by a predetermined feedback gain K to calculate a torque correction value t2 for canceling the vibration of the wheel drive shaft 17. Then, the correction processor 66 of the command value corrector 53 corrects the target torque command value Tm1 that has been subjected to the feedforward process to a vibration suppression torque command value Tm2 by using the torque correction value t2.

[0019] In this way, by generating pulse signals Pu, Pv, and Pw using the corrected vibration suppression torque command value Tm2, ​​it is possible to control the traveling motor 13 so as to cancel out the vibration of the wheel drive shaft 17, and it is possible to suppress the vibration of the drive system 12 during traveling. When the feedback gain K is set large, the feedback process is strengthened, so the responsiveness of the motor torque decreases, but the vibration of the drive system 12 can be effectively suppressed. When the feedback gain K is set small, the feedback process is weakened, so the drive system 12 is more likely to vibrate, but the responsiveness of the motor torque can be improved.

[0020] [Motor locked] Next, the motor lock state of the traveling motor 13 will be described. Fig. 5 is a diagram showing an example of a lock region. As shown in Fig. 5, a region where the rotation speed ωm of the traveling motor 13 falls below a threshold value Sb and the motor torque (torque) of the traveling motor 13 exceeds a threshold value Tb is set as a high torque and low rotation lock region. When the traveling motor 13 is in a motor lock state where it operates in the lock region, there is a risk that the current flowing through the stator coil 52 will increase locally. In other words, when the traveling motor 13 is in a motor lock state, the current flowing through the field coils Cu, Cv, and Cw will increase locally, and this may result in a local rise in the temperature of the stator coil 52.

[0021] Therefore, as shown in Fig. 3, the motor controller 50 is provided with a motor lock determination unit 67 that determines whether the traveling motor 13 is operating within the lock region, that is, whether the traveling motor 13 is in a motor lock state. The motor lock determination unit 67 determines whether the traveling motor 13 is operating within the lock region based on the motor torque and rotation speed of the traveling motor 13. If it is determined that the traveling motor 13 is in a motor lock state for a predetermined period of time, the command value correction unit 53 of the motor controller 50 actively reduces the vibration damping torque command value Tm2 in order to protect the traveling motor 13 from heat generation due to excessive current flow. This makes it possible to reduce the motor torque of the traveling motor 13, so that the traveling motor 13 can be operated outside the lock region as shown by the arrow α1, and the traveling motor 13 can be protected.

[0022] Incidentally, as a situation in which the traveling motor 13 operates in the lock region, it is assumed that the driver stops the vehicle 11 on an uphill road surface by adjusting the accelerator operation amount. That is, it is assumed that the force Fm that moves the vehicle 11 forward by the motor torque and the force Fg that moves the vehicle 11 backward by gravity are balanced with each other to stop the vehicle 11. In this way, when the vehicle 11 is stopped by the accelerator operation, if the motor lock state is determined to be present and the motor torque is reduced, there is a risk that the vehicle 11 will be reversed against the driver's intention. Therefore, when it is determined that the traveling motor 13 is in the motor lock state, the vehicle control device 10 of this embodiment does not immediately reduce the motor torque, but instead executes a lock release control to be described later to actively vibrate the vehicle 11. That is, the motor lock state of the traveling motor 13 is released by using vehicle vibration to make the driver aware of the occurrence of the motor lock state and prompting the driver to operate the accelerator or brake.

[0023] [Unlock control] The lock release control by the vehicle control device 10 will be described below. Fig. 6 and Fig. 7 are flowcharts showing an example of the execution procedure of the lock release control. The flowcharts shown in Fig. 6 and Fig. 7 are connected to each other at the points indicated by the symbols A and B. Fig. 8 is a diagram showing the transition of the operating state of the driving motor 13. In the following description, the frequency of the carrier signal Sc will be referred to as the "carrier frequency".

[0024] As shown in FIG. 6, in step S10, the feedback gain is set to a predetermined value K1, and the carrier frequency is set to a predetermined value FH. Next, in step S11, it is determined whether the traveling motor 13 is in a motor lock state. If it is determined in step S11 that the traveling motor 13 is in a motor lock state, the process proceeds to step S12, where it is determined whether the road surface gradient is an upward gradient exceeding a predetermined value SL1. If it is determined in step S12 that the road surface gradient is an upward gradient exceeding the predetermined value SL1, the process proceeds to step S13, where it is determined whether the elapsed time in the motor lock state exceeds a predetermined value Ti1. If it is determined in step S13 that the elapsed time exceeds the predetermined value Ti1, the process proceeds to step S14, where it is determined whether the accelerator operation amount by the driver falls below a predetermined value Ac1. If it is determined in step S14 that the accelerator operation amount falls below the predetermined value Ac1, that is, if there is a depression left on the accelerator pedal 45, the process proceeds to step S15, where the accelerator operation or brake operation for releasing the motor lock state is displayed to the driver on the meter panel 44.

[0025] That is, if the motor lock state continues for a predetermined time, the road gradient is an upward gradient, and the accelerator pedal 45 has a depression left, it is assumed that the vehicle 11 will be stopped on the uphill road by operating the accelerator. In this case, since there is a risk that the temperature of the stator coil 52 will excessively increase, the process proceeds to step S15, and the meter panel 44 displays a further depression of the accelerator pedal 45 or a further depression of the brake pedal 31 to prompt the driver to operate the accelerator or brake to release the motor lock state. Then, when the driver who has confirmed the display on the meter panel 44 further depresses the accelerator pedal 45, as shown by the arrow β1 in FIG. 8, the motor torque of the traveling motor 13 is increased, and the motor lock state of the traveling motor 13 is released. Also, when the driver who has confirmed the display on the meter panel 44 depresses the brake pedal 31, as shown by the arrow β2 in FIG. 8, the motor torque of the traveling motor 13 is reduced, and the motor lock state of the traveling motor 13 is released.

[0026] As shown in FIG. 6, when the driver is prompted to further depress the accelerator pedal 45 or the like in step S15, the process proceeds to step S16, where it is determined whether or not the motor lock state continues. If it is determined in step S16 that the motor lock state exists, the process proceeds to step S17, where it is determined whether or not the elapsed time in the motor lock state exceeds a predetermined value Ti2. If it is determined in step S17 that the elapsed time exceeds the predetermined value Ti2, the process proceeds to step S18, as shown in FIG. 7, where the feedback gain is reduced to a predetermined value K2 and the carrier frequency is reduced to a predetermined value FL. If it is determined in steps S11 and S16 that the driving motor 13 is not in a motor lock state, the routine ends without changing the feedback gain or the carrier frequency.

[0027] In step S18, by reducing the feedback gain to a predetermined value K2, the drivetrain 12 is actively vibrated by the driving motor 13, and the torque responsiveness of the driving motor 13 can be improved. Here, the feedback gain K2 is a gain smaller than the feedback gain K1, which is an initial value, and is set smaller than a predetermined threshold value from the viewpoint of vibrating the drivetrain 12. As described above, by setting the feedback gain small, the feedback process for suppressing the vibration of the drivetrain 12 is weakened, and therefore the vibration suppression torque command value Tm2 of the driving motor 13 is set so as to vibrate the drivetrain 12. In other words, by setting the feedback gain small, the drivetrain 12 can be actively vibrated. In addition, by setting the feedback gain small, the responsiveness of the motor torque can be improved in preparation for the subsequent accelerator operation.

[0028] In step S18, the carrier frequency is lowered to a predetermined value FL, so that the drive train 12 can be actively vibrated by the traveling motor 13. The carrier frequency FL used in step S18 is a frequency lower than the initial carrier frequency FH, and is a frequency set lower than a predetermined threshold value in terms of vibrating the drive train 12. Here, Figs. 9(A) and (B) are diagrams showing changes in energizing current depending on the carrier frequency. Fig. 9(A) shows the transition of energizing current when a carrier signal Sc1 with a carrier frequency of "FH" is used, and Fig. 9(B) shows the transition of energizing current when a carrier signal Sc2 with a carrier frequency of "FL" is used. Note that, although the field coil Cu of the traveling motor 13 will be described as an example, similar energizing currents also flow in the other field coils Cv and Cw.

[0029] As shown in FIG. 9(A) and (B), when the carrier signals Sc1 and Sc2 are below the command duty Du, the pulse signal Pu is set to a high level, and when the carrier signals Sc1 and Sc2 are above the command duty Du, the pulse signal Pu is set to a low level. Therefore, when the low-frequency carrier signal Sc2 is used, the number of switching operations of the inverter 20 can be reduced compared to when the high-frequency carrier signal Sc1 is used, and the current supplied to the field coil Cu can be changed roughly. In other words, by lowering the carrier frequency to a predetermined value FL, the pulse signal Pu can be set so as to increase the torque pulsation, i.e., the torque ripple, of the driving motor 13, and the drive system 12 can be actively vibrated by the torque pulsation. Furthermore, by lowering the carrier frequency to a predetermined value FL, the switching control sound of the inverter 20 can be brought closer to the human audible range.

[0030] As described above, in step S18 of FIG. 7, by decreasing the feedback gain to a predetermined value K2 and lowering the carrier frequency to a predetermined value FL, the drivetrain 12 can be actively vibrated by the traveling motor 13. That is, when the driver does not perform the accelerator operation or the like to release the motor lock state even though the accelerator operation or the like is displayed on the meter panel 44 for the driver, the vehicle 11 can be actively vibrated by the traveling motor 13, so that the driver can be made aware of the meter panel display. Furthermore, by lowering the carrier frequency to the predetermined value FL, the switching control sound of the inverter 20 can be brought closer to the human audible range, so that the driver can be made aware of the meter panel display not only by vibration but also by sound. This allows the driver to perform the accelerator operation or the brake operation, and the motor lock state of the traveling motor 13 can be released as shown by arrows β1 and β2 in FIG. 8.

[0031] Also, when the driver, who notices the meter panel display due to vehicle vibration, further depresses the accelerator pedal 45, the feedback gain is increased to a predetermined value K1, while the carrier frequency is maintained at a predetermined value FL until the motor lock state is resolved. That is, as shown in FIG. 7, in the above-mentioned step S18, when the feedback gain is decreased to a predetermined value K2 and the carrier frequency is lowered to a predetermined value FL, the process proceeds to step S19, where it is determined whether the accelerator pedal 45 is further depressed, that is, whether the accelerator operation amount exceeds a predetermined threshold value. In step S19, if it is determined that the accelerator pedal 45 is further depressed, and in the following step S20, it is determined that the elapsed time since the accelerator pedal 45 was further depressed exceeds a predetermined value Ti2, the process proceeds to step S21. In this step S21, the feedback gain is increased to the predetermined value K1, while the carrier frequency is maintained at the predetermined value FL.

[0032] That is, the situation in which the process proceeds to step S21 is one in which the driver, having noticed the vehicle vibration, depresses the accelerator pedal 45. In other words, since the purpose of the vehicle vibration has been achieved, the feedback gain is increased to a predetermined value K1 in order to suppress the vehicle vibration. Also, since the motor lock state of the traveling motor 13 continues in step S21, the carrier frequency is maintained at a low predetermined value FL to reduce the number of switching operations and suppress heat generation in the inverter 20. Note that, in the above-mentioned step S19, the threshold value compared with the accelerator operation amount to determine whether the accelerator pedal 45 has been depressed further is set to be greater than the accelerator operation amount required to release the motor lock state of the traveling motor 13.

[0033] Next, in step S22, it is determined whether the motor lock state has been eliminated. If it is determined in step S22 that the motor lock state has been eliminated, the process proceeds to step S23, where the carrier frequency is returned to the predetermined value FH, and the routine is terminated. On the other hand, if it is determined in step S19 that the accelerator pedal 45 is not depressed, the process proceeds to step S24, where it is determined whether the brake pedal 31 is depressed. Furthermore, if it is determined in step S24 that the brake pedal 31 is depressed and, in the following step S25, it is determined that the motor lock state has been eliminated, the process proceeds to step S23, where the feedback gain is returned to the predetermined value K1 and the carrier frequency is returned to the predetermined value FH, and the routine is terminated. The feedback gain K2 returned in step S23 is a gain that is set to be larger than a predetermined threshold value in terms of suppressing vibration of the drive system 12. The carrier frequency FH ​​returned in step S23 is a frequency that is set to be larger than a predetermined threshold value in terms of suppressing vibration of the drive system 12 and heat generation of the inverter 20.

[0034] [summary] As described above, when it is determined that the traction motor 13 is in a motor lock state, the feedback gain is set to be smaller than a predetermined threshold value, and the carrier frequency is set to be lower than a predetermined threshold value. This allows the traction motor 13 to actively vibrate the drivetrain 12, making the driver feel uncomfortable and encouraging him / her to perform a driving operation to eliminate the motor lock state. Furthermore, by setting the carrier frequency lower than the predetermined threshold value, the switching control sound of the inverter 20 can be brought closer to the human audible range, making it possible to make the driver feel uncomfortable and encouraging him / her to perform a driving operation to eliminate the motor lock state. This allows the driver to perform an accelerator operation or a brake operation, and the motor lock state of the traction motor 13 can be eliminated.

[0035] In the above description, the driver notices the occurrence of a motor lock state due to vibrations in the drive system 12 and performs an accelerator operation or brake operation, but a case is also assumed in which the driver does not perform an accelerator operation, etc. In this case, in order to protect the traveling motor 13 from excessive heat generation, the command value correction unit 53 of the motor controller 50 actively reduces the vibration damping torque command value Tm2. Furthermore, since the reduction of the vibration damping torque command value Tm2 may lead to unintended reverse movement by the driver, the brake control unit 42 of the main controller 40 controls the electric hydraulic brake 30, and the wheels 18 are braked by the electric hydraulic brake 30. In this way, the motor controller 50 has a protection function that protects the traveling motor 13 from heat generation in a motor lock state.

[0036] As described above, the motor controller 50 is provided with the command value correction unit 53 and the inverter control unit 54. When the driving motor 13 is in a motor lock state, the command value correction unit 53 and the inverter control unit 54 set the feedback gain to be smaller than a predetermined threshold value and set the carrier frequency to be lower than a predetermined threshold value. That is, the motor controller 50 has a notification function that notifies the driver of the motor lock state by vibrating the drive system 12. In this way, by providing a protection function and a notification function to one motor controller 50, the execution timing of the protection function can be delayed until just before protecting the driving motor 13 from excessive heat generation, and the driving performance can be ensured by suppressing the situation in which the motor torque is limited. That is, when the protection function and the notification function preceding it are provided in separate controllers, it is necessary to consider communication delays between the controllers, and therefore it is required to set the execution timing of the protection function with a sufficient time margin. In contrast, if the protection function and notification function are provided in a single controller, the timing of execution of the protection function can be delayed until just before protecting the driving motor 13 from excessive heat generation, thereby preventing situations in which motor torque is restricted and ensuring driving performance.

[0037] The present invention is not limited to the above-described embodiment, and it goes without saying that various modifications can be made without departing from the gist of the present invention. In the above description, an electric vehicle having only a driving motor 13 as a power source is exemplified as the vehicle 11 to which the vehicle control device 10 is applied, but the present invention is not limited to this, and may be a hybrid vehicle having a driving motor and an engine as a power source. In the above description, the main controller 40 is provided with the target torque setting unit 41, and the motor controller 50 is provided with the command value correction unit 53, the inverter control unit 54, and the motor lock determination unit 67, but the present invention is not limited to this. For example, the target torque setting unit 41, the command value correction unit 53, the inverter control unit 54, and the motor lock determination unit 67 may be provided in one controller, or may be provided separately in multiple controllers.

[0038] In the example shown in FIG. 5, the lock region is set as a region where the rotation speed of the traveling motor 13 falls below a certain threshold value Sb and the motor torque of the traveling motor 13 exceeds a certain threshold value Tb, but the present invention is not limited to this. For example, the threshold value Sb to be compared with the rotation speed of the traveling motor 13 may be changed according to the motor torque, and the threshold value Tb to be compared with the motor torque of the traveling motor 13 may be changed according to the rotation speed. Here, FIG. 10 is a diagram showing another example of the lock region. As shown in FIG. 10, a characteristic line (threshold value) Lx may be set based on the motor torque and the rotation speed, and the high torque side and low rotation side of the characteristic line Lx may be set as the lock region. It goes without saying that the characteristic line Lx is not limited to a straight line and may be a curved line.

[0039] In the above description, "K1" or "K2" is used as the feedback gain, and "FH" or "FL" is used as the carrier frequency, but the present invention is not limited to this. For example, it goes without saying that the feedback gain and the carrier frequency may be changed according to the rotation speed and motor torque of the traveling motor 13. Also, in the above flowchart, when the traveling motor 13 is in a motor lock state and the road gradient of the traveling road surface is an uphill gradient, the feedback gain is set small and the carrier frequency is set low, but the present invention is not limited to this. For example, when it is determined that the traveling motor 13 is in a motor lock state on a flat road, the feedback gain may be set small and the carrier frequency may be set low. [Explanation of symbols]

[0040] 10 Vehicle control device 11 Vehicles 12 Drive system 13. Driving motor (power source) 20 Inverter 41 Target torque setting unit (torque setting unit) 53 Command value correction unit (torque correction unit) 54 Inverter control unit 67 Motor lock determination unit SW1~SW6 Switching elements Tm1 Target torque command value (first torque command value) Tm2 Vibration suppression torque command value (second torque command value) Acc Accelerator operation amount ωm Rotational speed (control result) Sc, Sc1, Sc2 carrier signals Pu, Pv, Pw Pulse signal (drive signal) K, K1, K2 feedback gains FL,FH frequency

Claims

1. A vehicle control device that controls a driving motor that is a power source of a drive system, an inverter including a plurality of switching elements for supplying power to the driving motor; a torque setting unit that sets a first torque command value for the driving motor based on an accelerator operation amount; a torque correction unit that feeds back a control result of the driving motor to the first torque command value and corrects the first torque command value to a second torque command value that suppresses vibration of the drive system; an inverter control unit that generates a drive signal for the switching element based on the second torque command value and a carrier signal; a motor lock determination unit that determines whether the driving motor is in a motor lock state in which the driving motor operates in a lock region; having the torque correction unit sets a feedback gain used when correcting the first torque command value to the second torque command value to be smaller than a threshold value when it is determined that the traveling motor is in a motor lock state and a road surface gradient is determined to be an upward gradient, the inverter control unit sets a frequency of the carrier signal when generating the drive signal lower than a threshold value when it is determined that the traction motor is in a motor lock state and that a road surface gradient is an upward gradient. Vehicle control device.

2. 2. The vehicle control device according to claim 1, the lock region is a region in which the rotation speed of the driving motor is below a threshold value and the torque of the driving motor is above a threshold value. Vehicle control device.

3. 3. The vehicle control device according to claim 1, The torque correction unit is After it is determined that the driving motor is in a motor lock state and the feedback gain is set to a value smaller than a threshold value, when it is determined that the driving motor is in a motor lock state and the accelerator operation amount exceeds a threshold value, or when it is determined that the driving motor is not in a motor lock state, the feedback gain is set to be greater than a threshold value. Vehicle control device.

4. The vehicle control device according to any one of claims 1 to 3, The inverter control unit is After it is determined that the driving motor is in a motor lock state and the frequency of the carrier signal is set lower than a threshold value, When it is determined that the driving motor is not in a motor lock state, the frequency of the carrier signal is set to be higher than a threshold value. Vehicle control device.

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