Vehicle motor control device

Abstract

To provide a controller of a motor for a vehicle which can execute control of the motor according to individual vehicles.SOLUTION: A control device controls a motor for driving a driving wheel through a transmission mechanism. The control device includes: a control part which controls the motor based on a torque control value including a vibration component according to detection that the motor is mechanically constrained, and outputs a torque from the motor; and an estimation part for estimating resonance frequency that a driving mechanism having the motor, the driving wheel and the transmission mechanism causes torsional resonance on the basis of rotation speed of the motor when the motor outputs the torque according to the torque control value, wherein the control part controls the motor based on the torque control value while changing a frequency of the vibration component, and the estimation part estimates the resonance frequency on the basis of a change of the rotation speed of the motor according to the change of the frequency of the vibration component.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control device for an electric motor for a vehicle. [Background technology]

[0002] Conventionally, electric vehicles and other vehicles are equipped with electric motors to drive the drive wheels. In this case, the load on the drive wheels may cause the motor to be mechanically constrained. When an AC motor is driven through a three-phase inverter circuit, if the AC motor is locked, current may be concentrated in one inverter circuit.

[0003] Patent Document 1 discloses a vehicle motor control device that controls an AC motor that drives drive wheels via a drive torque transmission mechanism to output torque corresponding to a torque command value to the AC motor. When the output shaft of the AC motor is mechanically restrained from the load side and does not rotate, the vehicle motor control device described in Patent Document 1 changes the torque command value at the torsional resonance frequency of the drive torque transmission mechanism, thereby suppressing current concentration in one inverter circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2006-238560 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, the torsional resonance frequency of the drive torque transmission mechanism differs from vehicle to vehicle, and the torsional resonance frequency changes due to aging. For this reason, the technique described in Patent Document 1 has difficulty in matching the frequency of the torque command value to the resonance frequency of the drive torque transmission mechanism, and may not be able to achieve a sufficient effect.

[0006] The present invention has been made in view of the above circumstances, and one of the exemplary objects of the present invention is to provide a control device for an electric motor for a vehicle that can execute control of the electric motor according to each individual vehicle. [Means for solving the problem]

[0007] In order to solve the above problem, a control device for a vehicle electric motor according to one embodiment of the present invention controls an electric motor that drives a drive wheel via a transmission mechanism. The control device includes: a control unit that controls the electric motor based on a torque control value including a vibration component in response to detection of a state in which the electric motor is mechanically restrained, and causes the electric motor to output torque; and an estimation unit that estimates a resonance frequency at which a drive mechanism having the electric motor, the drive wheel, and the transmission mechanism causes torsional resonance, based on a rotation speed of the electric motor when the electric motor outputs torque according to the torque control value, the control unit controls the electric motor based on the torque control value while changing the frequency of the vibration component, and the estimation unit estimates the resonance frequency based on a change in the rotation speed of the electric motor corresponding to the change in the frequency of the vibration component.

[0008] Any combination of the above components, and any transformation of the present invention into a method, device, system, recording medium, computer program, etc., are also effective as aspects of the present invention. Effect of the Invention

[0009] According to the present invention, it is possible to provide a control device for a vehicle electric motor that can execute control of the electric motor according to each individual vehicle. [Brief description of the drawings]

[0010] [Figure 1] 1 is a schematic configuration diagram of a vehicle according to an embodiment of the present invention; [Diagram 2] 4A and 4B are diagrams showing the time change in torque of an electric motor, the frequency dependence of a transmission value which is a value indicating the degree to which torque is transmitted as vibration to a drive mechanism, and the time change in current flowing through an inverter element of an inverter circuit. [Diagram 3] FIG. 2 is a block diagram for explaining functions of a control device according to an embodiment of the present invention. [Figure 4] FIG. 11 is a diagram for explaining a first method for acquiring a transmission value. [Diagram 5] FIG. 11 is a diagram for explaining a second method for acquiring a transmission value. [Figure 6] 4 is a flowchart showing an example of a control process performed by a control device according to an embodiment of the present invention. [Figure 7] 13 is a flowchart showing a transmission value control process. [Figure 8] 7 is a diagram showing an example of a time change in a torque frequency and a time change in a transmission value when the control process shown in FIG. 6 is performed. FIG. [Figure 9] 4 is a flowchart showing an example of a control process performed by a control device according to an embodiment of the present invention. [Figure 10] 10 is a diagram illustrating an example of a time change in a torque frequency and a time change in a transmission value when the control process shown in FIG. 9 is performed. FIG. [Figure 11] 10 is a diagram illustrating an example of a time change in a torque frequency and a time change in a transmission value when the control process shown in FIG. 9 is performed. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, the embodiments of the present invention will be described in detail with reference to the drawings. In this specification and the drawings, components having substantially the same functional configurations are denoted by the same reference numerals, and duplicated explanations will be omitted. Furthermore, the configurations described below are merely examples, and do not limit the scope of the present invention in any way.

[0012] In addition, in this specification and drawings, multiple components having substantially the same functional configuration may be distinguished by adding different alphabets after the same reference numeral. However, when there is no need to particularly distinguish between multiple components having substantially the same functional configuration, only the same reference numeral is added to each of the multiple components. In the description of the drawings, the same reference numeral is added to the same elements, and duplicated descriptions are omitted as appropriate. For example, when there is no particular distinction between the drive wheels 120a and 120b, they are simply referred to as "drive wheels 120."

[0013] 1 is a schematic diagram of a vehicle 1 according to an embodiment of the present invention. The vehicle 1 according to this embodiment includes a drive mechanism 10, a PCU (Power Control Unit) 12, a battery 14, a control device 20, an electric motor sensor 22, an output shaft sensor 24, an axle sensor 26, and the like.

[0014] The vehicle 1 may be an electric vehicle such as a hybrid electric vehicle, a plug-in hybrid electric vehicle, a fuel cell electric vehicle, or a battery electric vehicle.

[0015] The drive mechanism 10 is a mechanism that is driven by receiving a supply of electric power from the PCU 12. The drive mechanism 10 includes an electric motor 100, drive wheels 120a, 120b, and a transmission mechanism 140. In addition to the electric motor 100, the drive mechanism 10 may further include an engine as a drive source for traveling.

[0016] The electric motor 100 receives power from the PCU 12 and outputs torque to drive the drive wheels 120a, 120b via a transmission mechanism 140. In this embodiment, the electric motor 100 is described as being a three-phase AC motor. However, the electric motor 100 is not limited to this and may be, for example, a DC motor.

[0017] The transmission mechanism 140 is a mechanism that transmits the torque output by the electric motor 100 to the drive wheels 120a, 120b. The transmission mechanism 140 includes an output shaft 142 connected to the electric motor 100, axles 144a, 144b connected to the drive wheels 120a, 120b, respectively, and a differential gear 146 that connects the output shaft 142 and the axles 144a, 144b.

[0018] The output shaft 142 rotates due to the torque output by the electric motor 100, and transmits the torque to the axles 144a, 144b via the differential gear 146. The axles 144a, 144b receive this torque and rotate, causing the drive wheels 120a, 120b to rotate.

[0019] The PCU 12 is a device that converts the power supplied from the battery 14 and supplies the converted power to the electric motor 100. The PCU 12 may have a boost converter, a smoothing circuit, an inverter circuit, etc. In this embodiment, since the electric motor 100 is a three-phase AC motor, the PCU 12 has a three-phase inverter circuit having a U phase, a V phase, and a W phase.

[0020] The electric motor sensor 22 is a sensor that measures the rotation speed of the electric motor 100 and transmits the measurement result to the control device 20. In addition, the output shaft sensor 24 is a sensor that measures the rotation speed of the output shaft 142 and transmits the measurement result to the control device 20. In addition, the axle sensor 26 is a sensor that measures the rotation speed of the axle 144 and transmits the measurement result to the control device 20.

[0021] The control device 20 is a device that controls the driving of the drive mechanism 10. The control device 20 may include a CPU (Central Processing Unit), a RAM (Read Access Memory), and a ROM (Read Only Memory). In this embodiment, the control device 20 controls the electric motor 100 via the PCU 12.

[0022] The control device 20 transmits a control signal to the PCU 12 and controls the electric motor 100 via the PCU 12. The control signal includes a torque control value that indicates the torque to be output by the electric motor 100, and the electric motor 100 is controlled based on this torque control value. The torque control value may be a constant value or a value that includes an oscillatory component. In this specification, the frequency of the oscillatory component is also referred to as the "torque frequency."

[0023] While the vehicle 1 is traveling, the electric motor 100 (or the output shaft 142 connected to the electric motor 100) may be mechanically restricted. More specifically, there may be cases where the electric motor 100 is not rotating or barely rotating even though torque is generated in the electric motor 100 due to the control of the control device 20. In this specification, such a state in which the electric motor 100 is mechanically restricted is also referred to as a locked state of the electric motor 100.

[0024] When the electric motor 100 is in a locked state, current may concentrate in inverter elements of some phases among the inverter elements included in the three-phase inverter circuit of the PCU 12. The control device 20 according to this embodiment oscillates the electrical angle of the electric motor 100 by including an oscillation component in the torque control value, and distributes the current flowing in the inverter circuit to the three-phase inverter elements, thereby making it possible to suppress current concentration in some inverter elements.

[0025] A preferred torque frequency will be described with reference to Fig. 2. Fig. 2 is a diagram showing the time change in torque of the electric motor 100, the frequency dependency of the transmission value, and the time change in the current flowing through the inverter element of the inverter circuit (hereinafter also referred to as "element current"). Here, the transmission value is a value indicating the likelihood of vibration occurring in the drive mechanism 10 due to the oscillating torque. Fig. 2(a) shows a case in which the torque of the drive mechanism 10 oscillates at a resonance frequency in torsional vibration (hereinafter also referred to as "torsional resonance frequency"), and Fig. 2(b) shows a case in which the torque oscillates at a frequency different from the torsional resonance frequency.

[0026] An upper limit is set for the torque output by the electric motor 100, and the electric motor 100 cannot output a torque greater than Trmax. In this case, in order to prevent the torque from exceeding Trmax, the average torque value Tr1 must be set lower than Trmax by at least the maximum amplitude of vibration. Under such constraints, when the torque is oscillated at the torsional resonance frequency f1 so that the maximum torque value becomes Trmax, the average value of the element current becomes Iave, and its maximum value is Imax.

[0027] In order to make the temperature of the element current the same as that of the torsional resonance frequency f1, it is necessary to make the magnitude of the element current the same as that of the torsional resonance frequency f1. In this case, if the frequency is different from the torsional resonance frequency f1, the transmission value will be lower than that of the torsional resonance frequency f1, and it will be necessary to make the motor output a torque that vibrates more than that of the torsional resonance frequency f1.

[0028] 2(b), when the torque vibrates at a frequency f2 different from the torsional resonance frequency f1, it is necessary to vibrate the torque with a larger amplitude than in the case of the torsional resonance frequency f1. In this case, in order to prevent the torque from exceeding Trmax, it is necessary to make the average torque value Tr2 lower than the average torque value Tr1 in the case of the torsional resonance frequency f1, and the driving force of the driving mechanism decreases.

[0029] In this way, when the frequency at which the torque oscillates is different from the resonant frequency, the magnitude of the average torque is limited. Therefore, in order to prevent the average torque from decreasing as much as possible, it is necessary to oscillate the torque control value at the torsional resonant frequency of the drive mechanism. However, due to product variations between vehicles and deterioration over time, it is difficult to match the torque frequency to the resonant frequency of the drive mechanism, and there are cases in which sufficient effect cannot be obtained.

[0030] The control device 20 according to the present embodiment, with the configuration described below, can estimate an appropriate torque frequency according to the torsional resonance frequency of the drive mechanism of each vehicle. This makes it possible to suppress current concentration in some circuit elements (e.g., inverter elements) while suppressing a decrease in the drive force of the drive mechanism.

[0031] 3 is a block diagram for explaining the function of the control device 20 according to the present embodiment. As shown in FIG.

[0032] The processing unit 21 executes various processes, for example, executes various processes based on sensor information and controls the driving of the drive mechanism 10. The processing unit 21 includes a sensor information acquisition unit 200, a detection unit 210, a transmission value acquisition unit 220, an estimation unit 230, and a control unit 240.

[0033] The sensor information acquiring unit 200 acquires various types of sensor information, and specifically, can acquire the measurement results of the electric motor sensor 22, the output shaft sensor 24, and the axle sensor 26. The sensor information acquiring unit 200 can transmit the acquired sensor information to the detection unit 210 and the transmission value acquiring unit 220.

[0034] The detection unit 210 can detect a state in which the electric motor 100 is mechanically restrained. Specifically, the detection unit 210 can detect a locked state of the electric motor 100 based on sensor information. More specifically, the detection unit 210 can detect a locked state of the electric motor 100 based on the rotation speed and torque control value of the electric motor 100. For example, the detection unit 210 may detect that the electric motor 100 is in a locked state when the rotation speed of the electric motor 100 is equal to or lower than a predetermined rotation speed (e.g., 100 rpm, etc.) and the torque control value output by the control device 20 is equal to or higher than a predetermined value (e.g., 1000 N·m, etc.). Furthermore, the detection unit 210 can transmit the detection result of the locked state to the control unit 240.

[0035] The transmission value acquisition unit 220 can acquire the transmission value based on the sensor information. For example, the transmission value acquisition unit 220 may calculate the transmission value based on the rotation speed of the electric motor 100 and the rotation speed of the output shaft 142, etc. The transmission value acquisition unit 220 may transmit the acquired transmission value to the estimation unit 230 and the control unit 240, or may store the acquired transmission value in the storage unit 250. A method in which the transmission value acquisition unit 220 acquires the transmission value will be described in detail later.

[0036] The estimation unit 230 estimates the torsional resonance frequency of the drive mechanism 10 based on the rotation speed of the electric motor 100 when the electric motor 100 is outputting a torque based on the torque control value. The torsional resonance frequency is determined by the configuration of the drive mechanism 10, and is generally several Hz to several tens of Hz. The estimation unit 230 may transmit the estimated torsional resonance frequency to the control unit 240, or may store it in the storage unit 250.

[0037] The control unit 240 controls the electric motor 100. Specifically, the control unit 240 transmits a control signal including a torque control value and the like to the PCU 12, and causes the electric motor 100 to output a torque according to the torque control value via the PCU 12.

[0038] In response to detection of a state in which the electric motor 100 is mechanically restrained, the control unit 240 controls the electric motor 100 based on a torque control value including a vibration component, and causes the electric motor 100 to output torque. Furthermore, the control unit 240 controls the electric motor 100 based on the torque control value while changing the torque frequency. The torque frequency may be, for example, a frequency that is set in advance, or may be a torsional resonance frequency estimated by the estimation unit 230.

[0039] Here, the magnitude of the vibration component of the torque control value may be such that the torque vibration caused by the vibration component is not transmitted to the drive wheels 120. This suppresses rattling of the drive wheels 120 caused by the torque vibration, and suppresses discomfort to passengers in the vehicle 1.

[0040] The storage unit 250 stores various types of information. The storage unit 250 stores programs for the processing unit 21 to perform various processes, and may store, for example, an estimation program for estimating a torsional resonance frequency and a control program for controlling the driving of the electric motor 100. The storage unit 250 may also store information such as the transmission value acquired by the transmission value acquisition unit 220, the estimation result by the estimator 230, and a control program for the controller 240 to execute control.

[0041] An example of a method in which the transmission value acquisition section 220 acquires a transmission value will be described with reference to Fig. 4 and Fig. 5. Fig. 4 is a diagram for explaining a first method for acquiring a transmission value, and Fig. 5 is a diagram for explaining a second method for acquiring a transmission value.

[0042] The four graphs in Figure 4 show, from top to bottom, the change in torque frequency over time, the change in rotational speed of electric motor 100 over time, the change in rotational speed of axle 144 over time, and the change in absolute value of the difference between the rotational speed of electric motor 100 and the rotational speed of axle 144 over time, respectively.

[0043] In the first method, the torque frequency starts at f3, and increases in a stepwise manner over time. Specifically, the torque frequency increases discontinuously every time a half-cycle of the period corresponding to the torque frequency elapses. For example, when a time T1 corresponding to a half-cycle of the period corresponding to the torque frequency f3 elapses, the torque frequency increases from f3 to f4.

[0044] In the first method, the transmission value acquisition unit 220 acquires the maximum absolute value of the value obtained by subtracting the rotation speed of the axle 144 from the rotation speed of the electric motor 100 during a period in which the torque control value oscillates at a certain torque frequency, as the transmission value of that torque frequency. In the example shown in Fig. 4, the values ​​of the four points shown in the graph of the absolute value of the difference in rotation speeds are acquired as the transmission value. For example, the transmission value acquisition unit 220 can acquire the absolute value V1 of the difference in rotation speeds as the transmission value of the torque frequency f3.

[0045] A second method of acquiring the transmission value will be described with reference to Fig. 5. The three graphs shown in Fig. 5 show, from the top, the time change of the torque frequency, the time change of the rotation speed of the electric motor 100, and the time change of the amount of change in the rotation speed of the electric motor. In the example shown in Fig. 5, similar to the example shown in Fig. 4, the torque frequency increases in a step manner with the passage of time. Furthermore, the torque frequency changes when a time equivalent to half a period of the corresponding period has passed. For example, when a time T2 equivalent to half a period of the period corresponding to f5 has passed, the torque frequency increases from f5 to f6.

[0046] In the second method, the transmission value acquisition unit 220 acquires the amount of change in the rotation speed of the electric motor 100 as the transmission value. In Fig. 5, the amount of change in the rotation speed of the electric motor 100 is shown as the absolute value of the value obtained by subtracting the rotation speed Vs from the rotation speed of the electric motor 100 and adding Vs. In the example shown in Fig. 5, the values ​​of four points shown in the graph of the amount of change in the rotation speed of the electric motor 100 are acquired as the transmission value. For example, the transmission value acquisition unit 220 can acquire the amount of change V2 in the rotation speed of the electric motor 100 as the transmission value of the torque frequency f5.

[0047] [First processing example] A first processing example of the control processing by the control device 20 according to the present embodiment will be described with reference to Figs. 6 to 8. Fig. 6 is a flowchart showing the first processing example of the control processing by the control device 20 according to the present embodiment. Fig. 7 is a flowchart showing the transmission value comparison processing in S113 shown in Fig. 6. Fig. 8 is a diagram showing an example of the change over time of the torque frequency and the change over time of the transmission value when the control processing shown in Fig. 6 is performed.

[0048] Hereinafter, the flow of the control process by the control device 20 will be described along the flowcharts shown in Figures 6 and 7, while referring to Figure 8. Here, it is assumed that when the control process shown in Figure 6 is started, the control unit 240 is controlling the electric motor 100 by a torque control value that does not include a vibration component.

[0049] First, the sensor information acquisition unit 200 acquires sensor information (S101). Next, the detection unit 210 determines whether or not the electric motor 100 is in a locked state based on the sensor information acquired in S101 (S103). For example, the detection unit 210 may determine that the electric motor 100 is in a locked state when the rotation speed of the electric motor 100 is 100 rpm or less and the torque control value is 1000 N·m or more. If it is determined in S103 that the electric motor 100 is not in a locked state, the control process shown in FIG. 6 ends. On the other hand, if it is determined in S103 that the electric motor 100 is in a locked state, the process proceeds to S105.

[0050] When it is determined in S103 that the electric motor 100 is in a locked state, the control unit 240 sets the torque frequency to 1 Hz (S105). Next, the control unit 240 starts to control the electric motor 100 based on a torque control value that includes an oscillation component (S107). Here, from time t0, the control unit 240 controls the electric motor 100 using a torque control value that oscillates at a torque frequency of 1 Hz.

[0051] Next, the sensor information acquiring unit 200 acquires sensor information (S109). Here, the sensor information acquiring unit 200 acquires sensor information such as the rotation speed of the electric motor 100 when the torque frequency is 1 Hz. Next, the transmission value acquiring unit 220 acquires a transmission value based on the sensor information acquired in S109 (S111). Here, the transmission value acquiring unit 220 acquires a transmission value C0 when the torque frequency is 1 Hz. In FIG. 8, the transmission value in the section from time t0 to t1 is shown as the acquired C0.

[0052] Next, the control device 20 performs a transmission value comparison process (S113). The transmission value comparison process will be described with reference to the flowchart shown in FIG. 7. First, the control unit 240 increases the torque frequency by 1 Hz (S115). In this example, when the process of S115 is performed for the first time, the control unit 240 increases the torque frequency from 1 Hz to 2 Hz at time t1, as shown in FIG. 8.

[0053] Next, the sensor information acquiring unit 200 acquires the sensor information (S117). Next, the transmission value acquiring unit 220 acquires the transmission value based on the sensor information acquired in S117 (S119). In this example, when the process of S117 is performed for the first time, for example, the transmission value acquiring unit 220 acquires the transmission value C1 when the torque frequency is 2 Hz from time t1 to t2.

[0054] Next, the transmission value acquisition unit 220 determines whether the transmission value acquired in S119 has decreased compared to the previous transmission value (S121). If the process of S119 has already been performed in the transmission value comparison process, it determines whether the transmission value acquired in this S119 has decreased compared to the transmission value acquired in the previous S119.

[0055] Furthermore, when the process of S119 is performed for the first time in the transmission value comparison process, the transmission value acquisition unit 220 determines whether the transmission value acquired in S119 has decreased compared to the transmission value acquired in S111 shown in Fig. 6. In the present example, since the transmission value C1 is higher than the transmission value C0, when the process of S119 is performed for the first time, it is determined that the transmission value has not decreased.

[0056] If it is determined in S121 that the transmission value has decreased, the transmission value comparison process ends. On the other hand, if it is determined in S121 that the transmission value has not decreased, the process returns to S115. Thereafter, the processes of S115 to S121 are repeated until it is determined in S121 that the transmission value has decreased.

[0057] In this example, the processing of S115 to S121 is repeated, the torque frequency increases from 2 Hz to 3 Hz, . . ., 6 Hz, and 7 Hz, and the transmission value of each torque frequency is acquired and compared. In this example, as shown in Fig. 8, the transmission value C2 when the torque frequency is 7 Hz (times t6 to t7) is lower than the transmission value C3 when the torque frequency is 6 Hz (times t5 to t6). Therefore, when the processing of S121 is performed when the torque frequency is 7 Hz (times t6 to t7), it is determined that the transmission value has decreased, and the transmission value comparison processing ends.

[0058] Returning to Fig. 6, the process after the transmission value comparison process is completed will be described. When the transmission value comparison process of S113 is completed, the estimation unit 230 estimates a value obtained by reducing the torque frequency by 1 Hz as the torsional resonance frequency of the drive mechanism 10. In this example, the estimation unit 230 estimates the torsional resonance frequency to be 6 Hz, which is obtained by reducing by 1 Hz from the torque frequency of 7 Hz at the end of S113. Next, the control unit 240 controls the electric motor 100 based on the torque control value that oscillates at the estimated torsional resonance frequency (S125), and the control process is completed.

[0059] The control device 20 according to this embodiment gradually changes the torque frequency, and estimates the torsional resonance frequency based on the change in the transmission value caused by the change in the torque frequency. In this example, the control device 20 estimates the torque frequency at which the transmission value reaches its highest value as the torsional resonance frequency in the process of changing the torque frequency. By controlling the electric motor 100 based on the torque control value that oscillates at this torsional resonance frequency, the control device 20 distributes the current flowing through the inverter circuit of the PCU 12 to the three-phase inverter elements even when the electric motor 100 is in a locked state, thereby preventing current concentration in a specific inverter element and protecting the inverter elements from heat.

[0060] In addition, the control device 20 according to this embodiment can oscillate the torque control value at a torque frequency when the transmission value is high, thereby suppressing a decrease in the drive torque of the drive wheels. Therefore, the control device 20 according to this embodiment can protect the inverter elements from heat while suppressing a decrease in the drive torque.

[0061] Furthermore, the control device 20 according to this embodiment can estimate the torsional resonance frequency according to product variations or aging deterioration, and therefore can control the electric motor according to each individual vehicle.

[0062] [Second processing example] A second processing example of the control processing by the control device 20 according to one embodiment of the present invention will be described with reference to Fig. 9 and Fig. 10. Fig. 9 is a flowchart showing the second processing example of the control processing by the control device 20. Fig. 10 is a diagram showing an example of the change over time of the torque frequency and the change over time of the transmission value when the control processing shown in Fig. 9 is performed.

[0063] An example of the control process will be described with reference to Fig. 9 and the flowchart shown in Fig. 10. Here, it is assumed that when the control process shown in Fig. 10 is started, the control unit 240 controls the electric motor 100 based on a torque control value that does not include a vibration component.

[0064] First, the processes of S201 and S203 are performed, but since these processes are substantially the same as the processes of S101 and S103 described with reference to Fig. 6, the description thereof will be omitted here. When it is determined in S103 that the electric motor 100 is not in a locked state, the control process shown in Fig. 9 ends.

[0065] When it is determined in S103 that the electric motor 100 is in a locked state, the control unit 240 sets the torque frequency to the fundamental frequency (S205). The fundamental frequency may be, for example, a torsional resonance frequency calculated in advance based on the configuration of the drive mechanism 10.

[0066] Next, the control unit 240 starts the control of the electric motor 100 based on the torque control value including the vibration component (S207). Here, the control unit 240 starts the control of the electric motor 100 based on the torque control value including the vibration component (S207) at a time t 10 In this embodiment, the electric motor 100 is controlled using a torque control value that oscillates at a fundamental frequency f7.

[0067] Next, the sensor information acquisition unit 200 acquires the sensor information (S209). Next, the transmission value acquisition unit 220 acquires a transmission value based on the sensor information acquired in S209 (S211). Next, the control device 20 performs a transmission value comparison process (S213). The transmission value comparison process in S213 is substantially the same as the transmission value comparison process described with reference to FIG. 7, and therefore a description thereof will be omitted here. In this example, the processes from S115 to S121 of the transmission value comparison process shown in FIG. 7 are performed once, and the time t 11 ~t 12 In the section, the transmission value comparison process is terminated when the torque frequency is f7+1 Hz. In this example, in the transmission value comparison process, when the torque frequency is f7+1 Hz (time t 11 ~t 12 ) and the transmission value C 11 is assumed to have been obtained.

[0068] Next, the control unit 240 reduces the torque frequency by 1 Hz (S215). 12 In step S217, the torque frequency is lowered from f7+1 Hz to the fundamental frequency f7. Next, the control unit 240 determines whether the torque frequency is the fundamental frequency or not (S217). If it is determined in S217 that the torque frequency is not the fundamental frequency, the control process shown in FIG. 9 ends, and the torque frequency at the time when the control process ends is estimated to be the torsional resonance frequency. On the other hand, if it is determined in S217 that the torque frequency is the fundamental frequency, the process proceeds to S219. The process when it is determined in S217 that the torque frequency is the fundamental frequency will be described below.

[0069] If it is determined in S217 that the torque frequency is the fundamental frequency, the sensor information acquisition unit 200 acquires sensor information (S219). Next, the transmission value acquisition unit 220 acquires a transmission value based on the sensor information acquired in S219 (S221). In this example, when the process of S221 is performed for the first time, the transmission value acquisition unit 220 acquires a transmission value when the torque frequency is the fundamental frequency f7 (at time t 12 ~t 13 ) transmission value C 10 The following shall be obtained:

[0070] Next, the transmission value acquisition unit 220 determines whether the transmission value acquired this time has decreased compared to the transmission value acquired last time (S223). When the process of S223 is performed for the first time, the transmission value acquisition unit 220 determines whether the transmission value acquired in S221 has decreased compared to the transmission value last acquired in S213. When the process of S223 has already been performed, the transmission value acquisition unit 220 determines whether the transmission value acquired in the immediately preceding S221 is lower than the transmission value acquired in the previous S221.

[0071] If it is determined in S223 that the transmission value has not decreased, the process proceeds to S225. On the other hand, if it is determined in S223 that the transmission value has decreased, the process proceeds to S227. In this example, when the process of S223 is performed for the first time, the time t 11 ~t 12 The transmission value C 11 Compared to time t 12 ~t 13 The transmission value C 10 Since the value is high, it is determined that the transmission value has not decreased.

[0072] If it is determined in S223 that the transmission value has not decreased, the control unit 240 decreases the torque frequency by 1 Hz (S225). Thereafter, the processes of S219 to S225 are repeated until it is determined in S223 that the transmission value has decreased. In this example, 14 ~t 15 At this point, the torque frequency becomes f7-2Hz and C 10The transmission value is acquired, and these processes are repeated until it is determined in S223 that the transmission value has decreased, and then the process proceeds to S227.

[0073] When it is determined in S223 that the transmission value has decreased, the estimation unit 230 adds 1 Hz to the torque frequency and estimates the torque frequency as the torsional resonance frequency (S227). Next, the control unit 240 controls the electric motor 100 based on the torque control value that oscillates at the torsional resonance frequency estimated in S227 (S229).

[0074] In the second processing example, the control device 20 changes the torque frequency based on a pre-calculated torsional resonance frequency (fundamental frequency) of the drive mechanism, making it possible to find a torque frequency with a high transmission value more quickly.

[0075] [Third processing example] The third processing example will be described with reference to the flowchart of FIG. 9 and with reference to FIG. 11. First, the processing of S201 to S211 is performed. However, since the processing of S201 to S211 is substantially the same as the processing described in the second processing example, the description of the processing of the control device 20 will be omitted here. By performing the processing of S201 to S211, the time t 20 In the torque frequency is set to the fundamental frequency f7, and the transmission value C 20 is obtained.

[0076] When the process of S211 is completed, the transmission value comparison process of S213 is performed. In the third processing example, in the transmission value comparison process, the processes of S115 to S121 described with reference to FIG. 7 are repeated twice. At this time, as shown in FIG. 22 ~t 23 At this torque frequency, the transmission value C 20 is obtained, and then at time t 23 At f7, the torque frequency decreases to f7+1Hz.

[0077] Next, in S217, the control unit 240 determines that the torque frequency is not the fundamental frequency f7, and the control process shown in FIG. 20 ~t 23 The highest transmission value in 21 The torque frequency f7+1 Hz is estimated to be the torsional resonance frequency. Also, it becomes possible to control the electric motor 100 based on the torque control value that oscillates at the estimated torsional resonance frequency.

[0078] [supplement] The present invention has been described above based on the embodiment. This embodiment is merely an example, and it will be understood by those skilled in the art that various modifications are possible in the combination of each component and each treatment process, and that such modifications are also within the scope of the present invention.

[0079] In the above embodiment, the control unit 240 has been described as changing the torque frequency at a fixed interval of 1 Hz. However, the present invention is not limited to this, and the control unit 240 may change the torque frequency at another frequency interval, or may change the torque frequency at an irregular interval.

[0080] In addition, each step in the processing of the control device 20 in this specification does not necessarily have to be processed in chronological order according to the order described in the flowchart. For example, each step in the processing of the control device 20 may be processed in an order different from the order described in the flowchart, or may be processed in parallel, as long as there is no logical contradiction.

[0081] It is also possible to create a computer program for causing hardware such as a CPU, ROM, and RAM built into the control device 20 to perform functions equivalent to those of the above-described components of the control device 20. Also provided is a storage medium having the computer program stored therein. [Explanation of symbols]

[0082] 1 vehicle, 10 drive mechanism, 12 PCU, 20 control device, 21 processing unit, 22 motor sensor, 24 output shaft sensor, 26 axle sensor, 100 motor, 140 transmission mechanism, 142 output shaft, 200 sensor information acquisition unit, 210 detection unit, 220 transmission value acquisition unit, 230 estimation unit, 240 control unit, 250 storage unit

Claims

[Claim 1] A control device that controls an electric motor that drives a drive wheel via a transmission mechanism, a control unit that controls the electric motor based on a torque control value including a vibration component in response to detection of a state in which the electric motor is mechanically restrained, and causes the electric motor to output torque; an estimation unit that estimates a resonance frequency at which a drive mechanism having the electric motor, the drive wheels, and the transmission mechanism causes torsional resonance, based on a rotation speed of the electric motor when the electric motor outputs a torque corresponding to the torque control value, the control unit controls the electric motor based on the torque control value while changing the frequency of the vibration component; The estimation unit estimates the resonant frequency based on a change in rotation speed of the electric motor corresponding to a change in frequency of the vibration component. A control device for a vehicle electric motor.

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