JP2020022268A - Drive control device for vehicle drive system - Google Patents

Abstract

To provide a drive control device that is applied to a drive system comprising a plurality of electric motors for driving a vehicle and that can reduce a bias of a temperature of each electric motor.SOLUTION: A drive control device (40) for driving a drive system for a vehicle driven by a plurality of electric motors comprises: a temperature acquisition part (41) that acquires temperatures of the plurality of electric motors; and a torque distribution part (44) that distributes required torque, required by the vehicle, to each of the electric motors so that temperature differences among the plurality of electric motors, based on the temperatures of the plurality of electric motors, acquired by the temperature acquisition part, can become small.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a drive control device applied to a drive system of a vehicle.

  Patent Literature 1 describes an electric vehicle including a first motor (electric motor) for driving front wheels of a vehicle and a second motor for driving rear wheels, which are separately provided. In this electric vehicle, the motor control device distributes a required torque required for the vehicle and controls driving of the first motor and the second motor. In order to suppress heat generation due to the driving of the motor, the motor control device sets a reference torque based on the temperature of each motor, and the motor that rotates for a predetermined time or more at a driving torque exceeding the reference torque is used. , The torque distribution control is executed to reduce the driving torque and increase the driving torque in the other electric motor.

JP 2012-95378 A

  In a vehicle provided with a plurality of motors for driving the wheels, it is preferable to minimize the bias in the temperature of each motor in order to equalize the characteristics and life of each motor. In the technique of Patent Document 1, the torque distribution control is performed based on whether or not the driving torque exceeds the reference torque in each of the electric motors for a predetermined time or more, so that it is difficult to reduce the temperature deviation among the electric motors. .

  In view of the above, an object of the present invention is to provide a drive control device that is applied to a drive system including a plurality of electric motors that drive a vehicle and that can reduce the unevenness in the temperature of each electric motor.

  The present invention provides a drive control device that drives a drive system of a vehicle driven by a plurality of electric motors. This drive control device, a temperature acquisition unit that acquires the temperature of the plurality of electric motors, such that a temperature difference between the plurality of electric motors based on the temperature of the plurality of electric motors acquired by the temperature acquisition unit is reduced. And a torque distribution unit that distributes a required torque required for the vehicle to the electric motors. And.

  According to the present invention, when the torque distribution unit distributes the required torque required for the vehicle to the plurality of motors, the temperature difference between the plurality of motors based on the temperatures of the plurality of motors acquired by the temperature acquisition unit is small. Distribute so that For this reason, it is possible to reduce the temperature deviation among the electric motors, and it is possible to prevent the characteristics and the life of the electric motors from being unequally reduced.

FIG. 1 is a schematic diagram of a drive system controlled by a drive control device according to a first embodiment. FIG. 1 is a schematic diagram of a drive control device according to a first embodiment. 5 is a flowchart of a drive control process according to the first embodiment. 4 is a time chart of drive control according to the first embodiment. 9 is a flowchart of a drive control process according to the second embodiment. 9 is a flowchart of a drive control process according to a third embodiment. 13 is a flowchart of a drive control process according to a fourth embodiment. 15 is a flowchart of a drive control process according to a fifth embodiment.

(1st Embodiment)
FIG. 1 shows a drive system 10 of a vehicle 20 according to the present embodiment. The drive system 10 is mounted on a vehicle 20 that is an electric vehicle (EV vehicle), and can drive drive shafts 21 and 22 of the vehicle 20. The drive system 10 includes a storage battery 11, MGs 12 and 13 as drive generator motors (motor generators: MG), inverters 14 and 15, and an ECU 40. FIG. 2 shows a schematic diagram of a specific configuration of the ECU 40.

  The storage battery 11 is a secondary battery, and more specifically, for example, a lithium ion storage battery having an output voltage of about 200 to 300 V.

  First MG 12 is connected to storage battery 11 via first inverter 14. Second MG 13 is connected to storage battery 11 via second inverter 15. When MGs 12 and 13 operate as generators, inverters 14 and 15 can convert the generated AC power into DC power and cause storage battery 11 to store the power. When MGs 12 and 13 operate as electric motors, inverters 14 and 15 can convert the DC power output from storage battery 11 into AC power and operate MGs 12 and 13.

  First MG 12 is connected to first drive shaft 21 arranged in front of vehicle 20. Wheels 31 and 32 that are front wheels of the vehicle 20 are connected to both ends of the first drive shaft 21. The second MG 13 is connected to a second drive shaft 22 arranged behind the vehicle 20. Wheels 33 and 34 that are rear wheels of the vehicle 20 are connected to both ends of the second drive shaft 22.

  The MGs 12 and 13 convert the rotational energy of the wheels 31 to 34 into electric power when operating as a generator, and convert the electric power supplied from the storage battery 11 into rotational energy when operating as a motor to drive the shaft 21. , 22 are driven.

  Braking devices 35 to 38 are installed on the wheels 31 to 34, respectively. The braking devices 35 to 38 are hydraulic brakes, and generate braking torque by applying a braking pressure to the corresponding wheels 31 to 34 to brake the wheels 31 to 34.

  The sensors 50 are conventionally known sensors capable of detecting the state of the vehicle 20 and the surrounding state of the vehicle 20. Specifically, the sensors 50 include an accelerator sensor 51, a vehicle speed sensor 52, a first temperature sensor 53, and a second temperature. The sensor 54 and the like can be exemplified. The first temperature sensor 53 is installed in the first MG 12, and can detect the temperature of the first MG. The second temperature sensor 54 is installed in the second MG 13 and can detect the temperature of the second MG 13.

  The ECU 40 is a drive control device that controls each component of the drive system 10 such as the storage battery 11, the MGs 12, 13, the inverters 14, 15, and the like. The ECU 40 is applied to the drive system 10 including the first MG 12 that drives the front wheels 31 and 32 of the vehicle 20 and the second MG 13 that drives the rear wheels 33 and 34.

  The ECU 40 can acquire information from the sensors 50 mounted on the vehicle 20 and output control signals to the storage battery 11, the MGs 12, 13, the inverters 14, 15, and the like. In addition, the information input from the outside of the vehicle 20 or from the driving support device can be acquired by the ECU 40 from an information terminal (not shown) mounted on the vehicle 20.

  The ECU 40 is mainly configured by a microcomputer including a CPU, a ROM, a RAM, a backup RAM, an I / O (all not shown), and executes various control programs stored in the ROM. Each function described in this document can be realized.

  The ECU 40 includes a temperature acquisition unit 41, a temperature prediction unit 42, a torque calculation unit 43, a torque distribution unit 44, and a control command unit 45.

  The temperature acquisition unit 41 acquires a first temperature T1 that is the temperature of the first MG 12 and a second temperature T2 that is the temperature of the second MG 13. The temperature acquisition unit 41 may use measured values input from the first temperature sensor 53 and the second temperature sensor 54 as the first temperature T1 and the second temperature T2. Further, the temperature acquisition unit 41 may use the predicted values of the first temperature T1 and the second temperature T2 predicted by the temperature prediction unit 42 described later as the first temperature T1 and the second temperature T2. Further, the temperature acquisition unit 41 predicts and detects a detected value (actually measured value) for the first temperature T1 and the second temperature T2 based on an operation input by a driver or the like, a driving situation of the vehicle 20, a traveling route situation, and the like. The value may be configured to be selectable.

  The temperature predicting unit 42 predicts a temporal change of the first temperature T1 and the second temperature T2. Specifically, for example, a detection value (actual measurement value) of the first temperature T1 detected by the first temperature sensor 53, a detection value (actual measurement value) of the second temperature T2 detected by the second temperature sensor 54, a navigation system, and the like. Of the traveling path of the vehicle 20, such as the situation of the traveling path of the vehicle 20, the outside temperature, the inclination and curvature of the traveling path, and the state of the traveling path where the vehicle 20 is traveling, the SOC of the storage battery 11, the vehicle speed, the accelerator opening, the vehicle interior temperature, and the like. The predicted value of the first temperature T1 and the predicted value of the second temperature T2 corresponding to the elapsed time from the present time can be calculated based on the traveling state of the vehicle 20 and the like. Specifically, for example, the first temperature T1 and the second temperature T2 can be predicted by predicting a time change of the required torque RC from the traveling history of the vehicle 20. Further, for example, the first temperature T1 and the second temperature T2 can be predicted by calculating the cooling speed of the MGs 12 and 13 from the vehicle interior temperature and the outside air temperature of the vehicle 20.

  The torque calculator 43 calculates a required torque RC required when the vehicle 20 travels. In the case where the MGs 12 and 13 are driven by power, the driving torque required to drive the drive shafts 21 and 22 can be calculated as the required torque RC based on the driving conditions of the vehicle 20 and the conditions of the traveling road. . When the MGs 12 and 13 are regeneratively operated, the braking torque required to brake the drive shafts 21 and 22 can be calculated as the required torque RC based on the driving conditions of the vehicle 20 and the conditions of the traveling road. .

  The torque distribution unit 44 distributes the required torque RC calculated by the torque calculation unit 43 into a first rotation torque R1 in which the first MG 12 rotates and a second rotation torque R2 in which the second MG 13 rotates. For example, when the required torque RC is secured only by the first rotation torque R1 and the second rotation torque R2, the first rotation torque R1 and the second rotation torque R2 are determined so as to satisfy RC = R1 + R2. At the time of torque distribution, each torque value may be calculated, or a distribution ratio may be calculated for each torque. The rotation torque of MGs 12 and 13 includes both the drive torque output by MGs 12 and 13 during power running operation and the regenerative torque input to MGs 12 and 13 during regenerative operation. Hereinafter, in this specification, the drive torque will be described as a positive rotation torque, and the regenerative torque will be described as a negative rotation torque.

  The torque distribution unit 44 determines the distribution of torque such that the temperature difference dT between the first temperature T1 and the second temperature T2 is small, and determines the distribution of torque regardless of the temperature difference dT. "Normal mode" can be executed. The torque distribution unit 44 may be configured to be able to select which mode to determine the distribution of torque.

  In the temperature difference mode, torque distribution section 44 rotates first MG 12 with respect to required torque RC required for vehicle 20 such that temperature difference dT between first temperature T1 and second temperature T2 is reduced. Distribution of the first rotation torque R1 and the second rotation torque R2 at which the second MG 13 rotates is determined.

  The torque distribution unit 44 is configured to select a higher-temperature high-temperature motor and a lower-temperature low-temperature motor from the first MG 12 and the second MG 13 based on the first temperature T1 and the second temperature T2. Is also good. Further, the torque distribution unit 44 reduces the rotational torque of the high-temperature electric motor so that the temperature difference dT between the first temperature T1 and the second temperature T2 is reduced, and according to the amount of decrease, the rotational torque of the low-temperature electric motor is reduced. May be configured to determine the amount of increase.

  Specifically, for example, when the first temperature T1 is higher than the second temperature T2 (T1> T2), the first MG 12 is selected as the high-temperature motor, and the second MG 13 is selected as the low-temperature motor. Then, torque distribution unit 44 decreases first rotation torque R1 of first MG 12 and increases second rotation torque R2 of second MG 13. The torque distribution unit 44 determines the increase amount of the second rotation torque R2 so as to complement the reduction amount of the first rotation torque R1. For example, the torque distribution is determined so that the reduction amount of the first rotation torque R1 and the increase amount of the second rotation torque R2 are substantially the same. Thus, the torque distribution can be determined so as to secure the required torque RC and reduce the temperature difference dT.

  The torque distribution unit 44 determines that the temperature difference dT is equal to or greater than a predetermined temperature difference threshold value A (dT ≧ A) and the first rotation torque R1 with respect to the required torque RC so as to reduce the temperature difference dT. It may be configured to determine the distribution with the second rotation torque R2. Furthermore, the torque distribution unit 44 may be configured to change the temperature difference threshold A according to which of the first temperature T1 and the second temperature T2 is higher. For example, the cooling speed of MGs 12 and 13 may be different depending on the installation positions of MGs 12 and 13 in vehicle 20. In this case, when the cooling rate of the first MG 12 is higher than the cooling rate of the second MG 13, when the first temperature T1 is higher than the second temperature T2, the temperature difference threshold A is set to be large, and the first temperature T1 When the temperature is lower than the second temperature T2, the temperature difference threshold value A is preferably set to be small.

  The torque distribution unit 44 sets the temperature thresholds B1 and B2 for the first temperature T1 or the second temperature T2, and selects the temperature difference mode and the normal mode based on the comparison with the temperature thresholds B1 and B2. May be configured. Specifically, for example, the torque distribution unit 44 determines that the first temperature T1 is equal to or higher than a predetermined first temperature threshold B1 (T1 ≧ B1) and the second temperature T2 is equal to or higher than a predetermined second temperature threshold B2 ( When T2 ≧ B2), the temperature difference mode may be selected, and in other cases, the normal mode may be selected. The first temperature threshold B1 and the second temperature threshold B2 can be set according to the temperature characteristics of the MGs 12, 13. When the cooling rate of the first MG 12 is faster than the cooling rate of the second MG 13, the first temperature threshold B1 can be set higher than the second temperature threshold B2.

  Alternatively, the first temperature T1 and the second temperature T2 may be compared using one temperature threshold B. In this case, the temperature threshold B may be changed according to which of the first temperature T1 and the second temperature T2 is higher. For example, when the cooling rate of the first MG 12 is higher than the cooling rate of the second MG 13, if the first temperature T1 is higher than the second temperature T2, the temperature threshold B is set to a higher temperature, and the first temperature T1 is When the temperature is lower than the second temperature T2, the temperature threshold B may be set to a low temperature.

  The torque distribution unit 44 sets a torque range (first rotation torque range, second rotation torque range) required for ensuring the running stability of the vehicle 20 for the first rotation torque R1 and the second rotation torque R2. May be. In this case, the distribution of the torque is determined such that the first rotation torque R1 falls within the first rotation torque range and the second rotation torque R2 falls within the second rotation torque range. The torque range required for ensuring the running stability of the vehicle 20 is calculated based on the driving status of the vehicle 20 of the vehicle 20, the status of the traveling route, and the like. When the distribution of the first rotation torque R1 and the second rotation torque R2 is calculated by the torque distribution ratio X (for example, X = R1 / R2), the first rotation torque range and the second rotation torque range are respectively set. Instead of setting, a range of the torque distribution ratio X may be set.

  For example, when the vehicle 20 slips, control is performed to reduce the drive torque of the drive shafts 21 and 22 for the purpose of suppressing the slip. Therefore, the first rotation torque range and the second rotation torque range are set to relatively low ranges. You.

  Further, the first rotation torque range and the second rotation torque range are set according to the inclination angle and the curvature of the traveling route and the posture of the vehicle 20 corresponding thereto. For example, when the vehicle 20 climbs a hill, the first rotation torque range is set relatively low so that the second rotation torque R2 for driving the rear wheels 33 and 34 is larger, and the second rotation torque range is compared. Set high. Conversely, when the vehicle 20 descends a slope, the first rotation torque range is set relatively high so that the first rotation torque R1 for driving the front wheels 31, 32 is increased, and the second rotation torque range is set. Set relatively low.

  When the drive system is configured to be able to independently control the rotational torque of the left and right wheels, when the vehicle is traveling on a curved road, the torque for driving the wheels on the outer corners of the curve is the wheel on the inner corners. The torque range may be determined so as to be larger than the torque for driving the motor. More specifically, using the vehicle 20, when the vehicle 20 travels on a curved road that makes a right turn, the torque range is set so that the driving torque of the wheels 31 and 33 on the outer side becomes larger than the wheels 32 and 34 on the inner side. May be set.

The required torque RC may be calculated as a braking torque. Hereinafter, in this specification, the braking torque will be described as a negative torque. In this case, the torque distribution unit 44 may determine the distribution of the braking torque at which the braking devices 35 to 38 brake the wheels 31 to 34, respectively. As the braking torque, the braking torque of the braking devices 35 and 36 for braking the front wheels 31 and 32 is defined as the first braking torque RB1, and the braking torque of the braking devices 37 and 38 for braking the wheels 33 and 34 as the rear wheels. Assuming the second braking torque RB2, the braking torques RB1 and RB2 can be calculated from the following equation (1).
RB1 + RB2 = RC- (R1 + R2) (1)

  The control command unit 45 transmits a control command signal to each component of the drive system 10 such as the storage battery 11, the MGs 12, 13 and the inverters 14, 15, and controls each component. For example, a torque command signal for each of the MGs 12 and 13 is created based on the required torque calculated by the torque calculation unit 43 and the torque distribution determined by the torque distribution unit 44 and output to the inverters 14 and 15 and the like. Thus, rotation torques R1, R2 of MGs 12, 13 can be controlled.

  FIG. 3 shows a flowchart of the drive control process executed by the ECU 40.

  First, in step S101, the required torque RC of the vehicle 20 is calculated. The ECU 40 calculates the torque required to drive the drive shafts 21 and 22 as the required torque RC based on the driving situation of the vehicle 20, the situation of the traveling road, and the like. After that, it advances to step S102.

  In the next step S102, a first temperature T1 and a second temperature T2 are obtained. Specifically, for example, the detection value of the first temperature sensor 53 is obtained as the first temperature T1, and the detection value of the second temperature sensor 54 is obtained as the second temperature T2. Thereafter, the process proceeds to step S103.

In step S103, a temperature difference dT between the first temperature T1 and the second temperature T2 is calculated. As shown in the following equation (2), the temperature difference dT is calculated as the absolute value abs (T1-T2) of the difference between the first temperature T1 and the second temperature T2. Thereafter, the process proceeds to step S108.
dT = abs (T1-T2) (2)

  In step S108, it is determined whether or not the temperature difference dT is equal to or larger than the temperature difference threshold A. If dT ≧ A, the process proceeds to step S109, and it is determined that torque distribution is performed in the temperature difference mode. If dT <A, the process proceeds to step S110, and it is determined that torque distribution is performed in the normal mode.

In step S109, the torque distribution is determined by the temperature difference mode. That is, required torque RC is distributed to MGs 12 and 13 such that temperature difference dT is reduced. More specifically, the ratio between the first rotation torque R1 and the second rotation torque R2 in the required torque RC is determined so as to satisfy the following expression (3).
RC = R1 + R2 (3)

  Specifically, for example, the first rotation torque R1 and the second rotation torque R2 are acquired, and when the first temperature T1 is higher than the second temperature T2 (T1> T2), the first rotation torque is obtained. The amount of reduction of the torque R1 and the amount of increase of the second rotation torque R2 are calculated. The torque distribution is determined so that the amount of decrease in the first rotational torque R1 and the amount of increase in the second rotational torque R2 are substantially the same. Conversely, when the first temperature T1 is lower than the second temperature T2 (T1 <T2), the amount of increase in the first rotation torque R1 and the amount of decrease in the second rotation torque R2 are calculated. The torque distribution is determined so that the amount of increase in the first rotational torque R1 and the amount of decrease in the second rotational torque R2 are substantially the same.

  By outputting a control command signal created based on the torque distribution determined in step S109 to inverters 14, 15, and the like, rotation torques R1, R2 of MGs 12, 13 are controlled to reduce temperature difference dT. be able to. After step S109, the process ends.

  In step S110, the torque distribution is determined in the normal mode. That is, similarly to the conventionally known technique, the torque distribution is determined in consideration of the drivability such as the traveling speed, acceleration, and fuel efficiency of the vehicle 20. After step S110, the process ends.

  FIG. 4 shows a time chart of the drive control processing according to the flowchart of FIG. In FIG. 4A, the horizontal axis represents time, and the vertical axis represents torque. The width of the region indicated by reference numeral 61 in the vertical axis direction indicates the first rotational torque R1, and the width of the region indicated by reference numeral 62 in the vertical axis direction indicates the second rotational torque R2. In FIG. 4B, the horizontal axis indicates time, and the vertical axis indicates the temperatures of MGs 12 and 13. The dashed line indicated by reference numeral 63 is the first temperature T1, and the solid line indicated by reference numeral 64 is the second temperature T2.

  In the period of time s0 to s1, as shown in FIG. 4B, the first temperature T1 and the second temperature T2 are substantially the same, and dT = 0. Therefore, the torque distribution is determined in the normal mode. As shown in FIG. 4A, the first MG 12 and the second MG 13 are driven with the same rotational torque, and R1 = R2 = RC / 2.

  As shown in FIG. 4B, after the time s1, the first temperature T1 becomes higher than the second temperature T2 (T1 ≧ T2). However, since the temperature difference dT is less than the temperature difference threshold A, the torque distribution is determined in the normal mode. At time s1 to s2, the temperature difference dT (= T1−T2) increases with time, and at time s2, the temperature difference dT reaches the temperature difference threshold A (dT = A).

  At time s2, the condition that the temperature difference dT is equal to or larger than the temperature difference threshold value A is satisfied, so that the torque distribution mode switches from the normal mode to the temperature difference mode. As a result, as shown in FIG. 4A, the first rotation torque R1 of the first MG12 that is the high-temperature motor is reduced, and the second rotation torque R2 of the second MG13 that is the low-temperature motor is increased. By making the amount of reduction of the first rotation torque R1 and the amount of increase of the second rotation torque R2 the same, it is possible to maintain a state where R1 + R2 = RC and RC are constant as shown in FIG. it can.

  In the period from time s2 to s3, the amount of reduction of the first rotation torque R1 and the amount of increase of the second rotation torque R2 are adjusted based on the temperature difference dT. Thereby, as shown in FIG. 4B, the temperature rise of the first temperature T1 is suppressed, and the temperature difference dT is reduced. At time s3, the temperature difference dT becomes smaller than the temperature difference threshold A (dT <A).

  At time s3, since the temperature difference dT is less than the temperature difference threshold A, the torque distribution mode switches from the temperature difference mode to the normal mode. Thus, as shown in FIG. 4A, the first MG 12 and the second MG 13 are driven with the same rotational torque, as in the period from time s0 to s2.

  As described above, according to the first embodiment, the ECU 40 controls the first MG 12 that drives the first wheels (wheels 31 and 32) of the vehicle 20 and the second MG 13 that drives the second wheels (wheels 33 and 34). It functions as a drive control device applied to the provided drive system 10, and includes a temperature acquisition unit 41 and a torque distribution unit 44. The temperature acquisition unit 41 acquires a first temperature T1 and a second temperature T2. The torque distribution unit 44 determines distribution of the first rotation torque R1 and the second rotation torque R2 in the required torque RC such that the temperature difference dT between the first temperature T1 and the second temperature T2 is reduced. Therefore, temperature difference dT between MGs 12 and 13 can be reduced by torque distribution unit 44.

  The torque distribution unit 44 selects a high-temperature motor and a low-temperature motor based on the first temperature T1 and the second temperature T2. For example, the higher temperature first MG 12 is selected as a high temperature motor, and the lower temperature second MG 13 is selected as a low temperature motor. Then, the amount of increase in second rotational torque R2 of second MG13, which is a low-temperature motor, is determined in accordance with the amount of reduction of first rotational torque R1 of first MG12, which is a high-temperature electric motor. For this reason, the reduction amount of the first rotation torque R1 can be compensated for by the increase amount of the second rotation torque R2.

  Further, the torque distribution unit 44 determines the distribution of the first rotational torque R1 and the second rotational torque R2 such that the amount of decrease in the first rotational torque R1 is substantially equal to the amount of increase in the second rotational torque R2. I do. For this reason, the reduction amount of the first rotation torque R1 can be complemented by the increase amount of the second rotation torque R2, and the required torque RC can be secured.

(2nd Embodiment)
FIG. 5 shows a flowchart of a drive control process executed by the ECU 40 according to the second embodiment. The second embodiment is an example of a drive control process when the MGs 12 and 13 execute a regenerative operation. The flowchart shown in FIG. 5 differs from the flowchart shown in FIG. 3 in the processing shown in steps S202 to S204. The processes shown in S201, S205, S206, and S208 to S210 shown in FIG. 5 are the same as the processes shown in S101 to S103 and S108 to S110 shown in FIG. 3, respectively, and the description is omitted by replacing the reference numerals. .

  In step S201, a required torque RC of the vehicle 20 is calculated. In this case, the required torque RC is calculated as a braking torque. Thereafter, the process proceeds to step S202.

  In step S202, the MGs 12, 13 are determined based on the rotational torques of the MGs 12, 13, which are input from the drive shafts 21, 22, the upper limit of the input power of the inverters 14, 15, and the state (SOC, temperature, etc.) of the storage battery 11. The regenerative limit torque RGh, which is the limit value of the sum of the regenerative torques of the above, is calculated. Regenerative limit torque RGh is a value at which the absolute value of the regenerative torque obtained by MGs 12 and 13 is maximized. The limit value of the regenerative torque of the first MG (the value of R1 when the amount of regenerative torque obtained by the first MG 12 is maximum) is R1h, and the limit value of the regenerative torque of the second MG (the amount of regenerative torque obtained by the second MG 13 is When the value of R2 at the maximum) is R2h, it can be calculated by RGh = R1h + R2h. Thereafter, the process proceeds to step S203.

  In step S203, it is determined whether or not the regeneration limit torque RGh exceeds the required torque RC. If RC ≧ RGh, the process proceeds to step S204, and a braking torque RB to be distributed to the braking devices 35 to 38 is calculated. Thereafter, the process proceeds to step S205. If RC <RGh in step S203, the process proceeds directly to step S205.

  After step S205, the distribution of the first rotation torque R1 and the second rotation torque R2 in the required torque RC is determined by the same processing as in the first embodiment. When the process of step S204 is performed, the distribution of the first rotation torque R1, the second rotation torque R2, the first braking torque RB1, and the second braking torque RB2 is calculated based on the above equation (1). .

  As described above, according to the second embodiment, the ECU 40 determines whether the required torque RC is the first regenerative torque that is the rotational torque during regenerative operation of the first MG 12 and the second regenerative torque that is the rotational torque during regenerative operation of the second MG 13. Distribution of the second regenerative torque, the first braking torque RB1 in which the braking devices 35, 36 brake the front wheels 31, 32, and the second braking torque RB2 in which the braking devices 37, 38 brake the rear wheels 33, 34. To determine. By distributing the required torque RC also to the braking devices 35 to 38, the temperature burden on the MGs 12, 13 is reduced, so that the temperature rise of the MGs 12, 13 can be suppressed.

(Third embodiment)
FIG. 6 shows a flowchart of a drive control process executed by the ECU 40 according to the third embodiment. The third embodiment is an example of a drive control process for comparing and determining the first temperature T1 and the second temperature T2 with a temperature threshold. The flowchart shown in FIG. 6 differs from the flowchart shown in FIG. 3 in the processing shown in steps S304 to S306. The processes shown in S301 to S303, S309, and S310 shown in FIG. 6 are the same as the processes shown in S101 to S103, S109, and S110 shown in FIG. 3, respectively, and thus the description will be omitted by replacing the reference numerals.

  In steps S301 to S303, the required torque RC is calculated, the first temperature T1 and the second temperature T2 are obtained, the temperature difference dT is calculated, and the process proceeds to step S304. In step S304, similarly to step S108 shown in FIG. 3, it is determined whether the temperature difference dT is equal to or larger than the temperature difference threshold A. If dT ≧ A, the process proceeds to step S305. If dT <A, the process proceeds to step S310, and it is determined that torque distribution is performed in the normal mode.

  In step S305, it is determined whether the first temperature T1 is equal to or higher than the first temperature threshold B1. Note that the first temperature threshold B1 is set to a temperature at which the temperature load of the first MG 12 does not cause a problem in consideration of the deterioration of the temperature characteristics and the life of the first MG 12. If T1 ≧ B1, the process proceeds to step S306. If T1 <B1, the process proceeds to step S310, and it is determined that torque distribution is performed in the normal mode.

  In step S306, it is determined whether the second temperature T2 is equal to or higher than the second temperature threshold B2. The second temperature threshold value B2 is set to a temperature at which the temperature load of the second MG 13 does not matter in consideration of the temperature characteristics and the life of the second MG 13. If T2 ≧ B2, the process proceeds to step S309, and it is determined that torque distribution is performed in the temperature difference mode. If T2 <B2, the process proceeds to step S310, and it is determined that torque distribution is to be performed in the normal mode. Since the cooling rate of the first MG 12 is higher than the cooling rate of the second MG 13, B1> B2 is set.

  After step S305, the distribution of the first rotation torque R1 and the second rotation torque R2 in the required torque RC is determined by the same processing as in the first embodiment.

  As described above, according to the third embodiment, the ECU 40 determines that the first temperature T1 is equal to or higher than the predetermined first temperature threshold B1 and that the second temperature T2 is equal to or higher than the predetermined second temperature threshold B2. As a condition, distribution with torque is determined in the temperature difference mode. When the first temperature T1 and the second temperature T2 are sufficiently low and there is no problem that the MGs 12 and 13 are deteriorated by the temperature load, the normal mode is selected and the required torque RC is distributed with priority given to drivability. be able to.

  Further, for the first temperature T1 of the first MG 12 having a high cooling rate, it is possible to perform the torque distribution giving priority to drivability by making it difficult to select the temperature difference mode using the higher first temperature threshold B1. it can. For the second temperature T2 of the second MG 13 having a slow cooling speed, the lower temperature threshold mode B2 is used to make it easier to select the temperature difference mode, thereby performing the torque distribution giving priority to the reduction of the temperature difference dT. Can be.

(Fourth embodiment)
FIG. 7 shows a flowchart of a drive control process executed by the ECU 40 according to the fourth embodiment. The fourth embodiment is an example of a drive control process for changing the temperature difference threshold A based on the first temperature T1 and the second temperature T2. The flowchart shown in FIG. 7 differs from the flowchart shown in FIG. 3 in the processing shown in steps S404 to S406. The processes shown in S401 to S403 and S408 to S410 shown in FIG. 7 are the same as the processes shown in S101 to S103 and S108 to S110 shown in FIG. 3, respectively, and thus the description will be omitted by replacing the reference numerals.

  In steps S401 to S403, the required torque RC is calculated, the first temperature T1 and the second temperature T2 are obtained, the temperature difference dT is calculated, and the process proceeds to step S404.

  In step S404, it is determined whether the first temperature T1 is higher than the second temperature T2. If T1> T2, the process proceeds to step S405, and the temperature difference threshold A is set to the first temperature difference threshold A1 (A = A1). If T1 <T2, the process proceeds to step S406, and the temperature difference threshold A is set to the second temperature difference threshold A2 (A = A2). Since the cooling rate of the first MG 12 is faster than the cooling rate of the second MG 13, A1> A2 is set. After steps S405 and S406, the process proceeds to step S408.

  After step S408, distribution of the first rotation torque R1 and the second rotation torque R2 in the required torque RC is determined by the same processing as in the first embodiment. The temperature difference threshold value A used in step S408 is set to the first temperature difference threshold value A1 or the second temperature difference threshold value A2 in the processing in steps S404 to S406.

  As described above, according to the fourth embodiment, the ECU 40 changes the temperature difference threshold value A according to which of the first temperature T1 and the second temperature T2 is higher. For this reason, the required torque RC can be appropriately distributed according to the case where the first MG 12 and the second MG 13 have different temperature characteristics.

  Further, when the first MG 12 having a high cooling rate becomes higher in temperature, the temperature distribution mode is selected with a higher first temperature difference threshold A1 so as to make it difficult to select the temperature difference mode, thereby performing torque distribution giving priority to drivability. Can be. When the temperature of the second MG 13 having a low cooling rate becomes higher, the temperature distribution mode is easily selected using the lower second temperature difference threshold value A2, thereby performing the torque distribution giving priority to the reduction of the temperature difference dT. be able to.

(Fifth embodiment)
FIG. 8 shows a flowchart of a drive control process executed by the ECU 40 according to the fifth embodiment. In the fifth embodiment, whether the torque distribution determined by the torque distribution unit 44 is within a torque range (hereinafter, sometimes referred to as a stable torque range) required to ensure the running stability of the vehicle 20. 7 is an example of a drive control process including a process of determining whether or not the driving control is performed; The flowchart shown in FIG. 8 differs from the flowchart shown in FIG. 3 in the processing shown in steps S511 to S513. The processes shown in S501 to S510 shown in FIG. 8 are the same as the processes shown in S101 to S110 shown in FIG. 3 respectively, and thus the description will be omitted by replacing the reference numerals.

  In step S509 or S510, the required torque RC is divided into the first rotation torque R1 and the second rotation torque R2 in the temperature difference mode or the normal mode, and the process proceeds to step S511.

  In step S511, a torque distribution ratio X = R1 / R2 is calculated. Further, a lower limit value XL and an upper limit value XH of the torque distribution ratio that define the stable torque range of the vehicle 20 are set. The lower limit value XL and the upper limit value XH of the torque distribution ratio are calculated based on the driving situation of the vehicle 20, the situation of the traveling route, and the like. For example, when climbing a hill, the range of the torque distribution ratio X is set relatively low so that the second rotational torque R2 for driving the rear wheels becomes larger. Conversely, when descending a slope, the range of the torque distribution ratio X is set relatively high so that the first rotational torque R1 for driving the front wheels becomes larger. After step S511, the process proceeds to step S512.

  In step S512, it is determined whether or not the torque distribution ratio X calculated in step S511 is within the range of the torque distribution ratio set in step S511. That is, it is determined whether or not XL ≦ X ≦ XH is satisfied. If XL ≦ X ≦ XH is not satisfied, the process proceeds to step S513, and the torque distribution ratio X is recalculated within the range of the torque distribution ratio set in step S511. That is, the torque distribution ratio X is recalculated within a range satisfying XL ≦ X ≦ XH. If XL ≦ X ≦ XH is satisfied, the process ends.

  As described above, according to the fifth embodiment, the ECU 40 calculates the torque distribution ratio X between the first rotation torque R1 and the second rotation torque R2, and determines the lower limit of the torque distribution ratio that defines the stable torque range of the vehicle 20. The value XL and the upper limit XH are calculated. When the torque distribution ratio X calculated in the temperature difference mode or the normal mode is not within the torque range (when XL ≦ X ≦ XH is not satisfied), the torque is redistributed to satisfy the torque range. Execute. Therefore, priority can be given to ensuring the running stability of vehicle 20, and control can be performed to reduce temperature difference dT between MGs 12, 13 within the allowable torque range.

  According to the above embodiment, the following effects can be obtained.

  The ECU 40 functions as a drive control device that drives a drive system of a vehicle driven by the plurality of electric motors (MG12, 13), and acquires a temperature (T1, T2) of the plurality of electric motors; And a torque distribution unit 44 that distributes a required torque RC required of the vehicle 20 to each motor such that a temperature difference dT between the plurality of motors obtained from the temperatures of the plurality of motors acquired by the unit 41 is reduced. Prepare. Therefore, temperature difference dT between MGs 12 and 13 can be reduced by torque distribution unit 44.

  According to one embodiment, the torque distribution unit 44 determines the rotational torque from the plurality of motors (MG12, 13) based on the temperatures (T1, T2) of the plurality of motors acquired by the temperature acquisition unit 41. A high-temperature motor to be reduced and a low-temperature motor to increase the rotation torque are selected, and the torque distribution unit 44 is configured to determine the increase in the rotation torque of the low-temperature motor according to the decrease in the rotation torque of the high-temperature motor. Have been. With this configuration, the temperature difference dT between the plurality of electric motors (MGs 12, 13) can be reduced. Further, the amount of decrease in the rotational torque of the high-temperature motor can be compensated for by the amount of increase in the rotational torque of the low-temperature motor. Further, the torque distribution unit 44 may be configured to determine the amount of decrease in the rotational torque of the high-temperature motor and the amount of increase in the rotational torque of the low-temperature motor to be substantially the same. The reduction amount of the rotation torque of the high-temperature motor can be complemented by the increase amount of the rotation torque of the low-temperature motor, and the required torque RC can be secured.

  The drive system 10 includes braking devices 35 to 38 that brake the wheels 31 to 34 of the vehicle 20, and includes MGs 12 and 13 that are generator motors as a plurality of motors. In this case, the torque distribution unit 44 may be configured to distribute the required torque RC to the MGs 12, 13 and the braking devices 35 to 38. Since the load on the generator motors (MG12, 13) is reduced by distributing the required torque RC to the braking devices 35 to 38, the temperature rise of the generator motors (MG12, 13) can be suppressed.

  According to one embodiment, the torque distribution unit 44 determines that the temperature difference dT between the motors (MG12, 13) obtained from the temperatures of the plurality of motors (MG12, 13) acquired by the temperature acquisition unit 41 is a predetermined temperature. On condition that the difference is equal to or larger than the difference threshold A, the required torque RC is distributed to the electric motors (MG12, MG13) so that the temperature difference dT becomes small. When the temperature difference dT is small enough not to exceed the temperature difference threshold value A, and there is no problem that the motors (MG12, 13) are deteriorated unequally, the normal mode is selected and priority is given to drivability. The torque RC can be distributed. Furthermore, torque distribution unit 44 may be configured to change temperature difference threshold value A according to which of the plurality of electric motors (MGs 12, 13) has the highest temperature. The required torque RC can be appropriately distributed according to a case where the temperature characteristics of the plurality of electric motors (MG12, 13) are different.

  According to one embodiment, the torque distribution unit 44 determines whether the temperature of the plurality of electric motors (MG12, 13) acquired by the temperature acquisition unit 41 is equal to or higher than a predetermined temperature threshold (B1, B2). The required torque RC is applied to each of the motors (MG12, 13) such that the temperature difference dT between the motors (MG12, 13) obtained from the temperatures of the plurality of motors (MG12, 13) obtained by the obtaining unit 41 is reduced. It is configured to distribute. When the temperature of each of the electric motors (MG12, 13) is sufficiently low and deterioration due to temperature load does not pose a problem, the normal mode is selected, and the required torque RC can be distributed with priority on drivability. Further, torque distribution unit 44 may be configured to change temperature difference threshold value A according to which of the plurality of electric motors (MGs 12, 13) has the highest temperature. Requested torque RC can be appropriately distributed according to the temperature characteristics of each electric motor (MG 12, 13).

  According to one embodiment, the torque distribution unit 44 sets a torque range (stable torque range) required to secure the running stability of the vehicle 20 for each of the plurality of electric motors (MG12, 13). The configuration is such that the required torque RC is distributed to each of the electric motors (MG12, 13) within the stable torque range of each of the electric motors (MG12, 13). The control to reduce the temperature difference dT between the plurality of electric motors (MG12, 13) within the stable torque range can be executed with priority given to ensuring the running stability of the vehicle 20.

  The drive system 10 includes temperature sensors 53 and 54 for detecting the temperatures of the plurality of electric motors (MG12 and 13), and the ECU 40 calculates a predicted value of the temperature of the plurality of electric motors (MG12 and 13) after a predetermined time has elapsed. A temperature predicting unit 42 for predicting the temperature is provided. In this case, the temperature acquisition unit 41 acquires the detection values of the temperature sensors 53 and 54 and the prediction values predicted by the temperature prediction unit 42 as the temperatures (T1 and T2) of the plurality of electric motors (MG12 and 13). It may be configured to be possible. In addition, in the temperature difference mode, the torque distribution unit 44 determines the required torque based on the temperature difference dT calculated using one or both of the detected value and the predicted value of the temperature of the plurality of electric motors (MG12, 13). It may be configured to distribute RC to each motor. Since the detected values of the temperatures of the plurality of motors (MG12, 13) can be used as appropriate with the predicted values, the temperature difference between the motors (MG12, 13) can be reduced more reliably.

(Other embodiments)
-In above-mentioned embodiment, although demonstrated the vehicle 20 provided with two generator motors (MG12, 13), it is not limited to this. The technical concept described in each of the above embodiments can also be applied to a drive system of a vehicle including three or more motors or generator motors, and the temperature difference between each motor or the generator motor described in each of the above embodiments can be applied. Can be configured to obtain an effect such as reduction of

  The technical concept described in each of the above embodiments can be applied to a drive system of a vehicle having an internal combustion engine as a torque generation source, in addition to the generator motor, and each of the motors or The present invention can be configured to obtain operational effects such as reducing the temperature difference of the generator motor.

  In the above, the case where one ECU 40 controls each configuration of the drive system 10 has been described as an example, but the present invention is not limited to this. Similarly to the ECU 40, a main ECU including a temperature acquisition unit 41, a temperature prediction unit 42, a torque calculation unit 43, a torque distribution unit 44, and a control command unit 45, and the MGs 12, 13, the inverters 14, 15, and the like. An ECU for controlling each of the components may be separately provided. In this case, the main ECU may be configured to transmit a control command signal to an ECU that controls each component of the drive system 10 and control each component.

DESCRIPTION OF SYMBOLS 10 ... Drive system, 12 ... 1st MG, 13 ... 2nd MG, 20 ... Vehicle, 40 ... ECU, 41 ... Temperature acquisition part, 44 ... Torque distribution part

Claims (10)

A drive control device (40) for driving a drive system (10) of a vehicle (20) driven by a plurality of electric motors (12, 13),
A temperature acquisition unit (41) for acquiring temperatures of the plurality of electric motors;
A torque distribution unit (44) that distributes a required torque required for the vehicle to each of the motors such that a temperature difference between the plurality of electric motors based on the temperatures of the plurality of electric motors acquired by the temperature acquisition unit is reduced. And a drive control device comprising: The torque distribution unit, based on the temperature of the plurality of electric motors acquired by the temperature acquisition unit, among the plurality of electric motors, a high-temperature electric motor that reduces rotational torque, and a low-temperature electric motor that increases rotational torque. Select,
2. The drive control device according to claim 1, wherein the amount of increase in the rotational torque of the low-temperature motor is determined according to the amount of decrease in the rotational torque of the high-temperature motor. 3.   3. The drive control device according to claim 2, wherein the torque distribution unit determines that the amount of decrease in the rotational torque of the high-temperature motor and the amount of increase in the rotational torque of the low-temperature motor are substantially the same. 4. The drive system includes a braking device (35 to 38) that brakes wheels (31 to 34) of the vehicle,
The plurality of motors is a generator motor capable of a power running operation for driving the wheels and a regenerative operation for generating power by rotational energy of the wheels,
The drive control device according to claim 1, wherein the torque distribution unit distributes the required torque to the generator motor and the braking device.   The torque distributing unit is obtained by the temperature obtaining unit on condition that a temperature difference between the plurality of electric motors based on the temperatures of the plurality of electric motors obtained by the temperature obtaining unit is equal to or greater than a predetermined temperature difference threshold. The drive control device according to any one of claims 1 to 4, wherein the required torque is distributed to each of the motors such that the determined temperature difference between the plurality of motors is reduced.   The drive control device according to claim 5, wherein the torque distribution unit changes the temperature difference threshold value according to which of the plurality of electric motors has the highest temperature.   The torque distribution unit is based on the temperature of the plurality of electric motors acquired by the temperature acquisition unit, provided that the temperatures of the plurality of electric motors acquired by the temperature acquisition unit are equal to or higher than a predetermined temperature threshold. The drive control device according to any one of claims 1 to 5, wherein the required torque is distributed to each of the motors such that a temperature difference between the plurality of motors is reduced.   The drive control device according to claim 7, wherein the torque distribution unit changes the temperature threshold according to which of the plurality of electric motors has the highest temperature.   The torque distribution unit sets a torque range required to ensure the running stability of the vehicle for each of the plurality of electric motors, and within the torque range set for each of the plurality of electric motors. The drive control device according to any one of claims 1 to 8, wherein the required torque is distributed to the electric motors. The drive system includes a temperature sensor (53, 54) for detecting a temperature of the plurality of electric motors,
The drive control device includes a temperature prediction unit (42) that predicts a predicted value of a temperature of the plurality of electric motors after a predetermined time has elapsed.
The temperature acquisition unit, as the temperature of the plurality of electric motors, the detection value of the temperature sensor, it is possible to acquire a predicted value by the temperature prediction unit,
The torque distribution unit is configured to reduce the required torque based on at least one of the detected value and the predicted value acquired by the temperature acquisition unit so that a temperature difference between the plurality of electric motors is reduced. The drive control device according to any one of claims 1 to 9, wherein the drive control device is distributed to each electric motor.

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