Motor control device

Abstract

To protect a battery mounted on a vehicle and efficiently utilize the power of the battery.SOLUTION: A motor control device includes a plurality of processors (a motor ECU36 and a motor ECU37), and each processor derives first power to be consumed in the future and second power currently consumed by a motor corresponding to the processor. Acquiring second power from the other processor, deriving third power by adding the derived second power and the second power acquired from the other processor, acquiring fourth power being output from the battery, acquiring a power limit value of the battery, correcting the power limit value based on the third power and the fourth power to derive a control power limit value, and distributing the control power limit value to the motor corresponding to the processor; A power value distributed to the motor corresponding to the own processor is corrected based on the first power and the second power derived by the own processor to derive an individual power limit value, and when the first power exceeds the individual power limit value, the torque instruction value is corrected.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The technology of the present disclosure relates to a motor control device. [Background technology]

[0002] Patent Document 1 describes a vehicle charge / discharge control device that includes a storage device that stores power generated by a generator, an electric motor that functions as a drive source for the vehicle based on power from the generator or the storage device and that generates power regeneratively when the vehicle is braked to charge the storage device, and a controller that controls these devices in an integrated manner, wherein the controller is equipped with a chargeable power calculation means that calculates the power that can be charged by the storage device depending on the state of the storage device, and is equipped with a regenerative power consumption means that consumes power that exceeds the calculated chargeable power of the regenerative power generated when the vehicle is braked, and the controller is equipped with a chargeable power correction value calculation means that calculates a chargeable power correction value that corrects the chargeable power of the storage device depending on the chargeable power and a control error of the regenerative power consumption means, and a chargeable power correction value switching means that switches the chargeable power correction value depending on the control error of the regenerative power consumption means, and the regenerative power consumption means consumes the amount of regenerative power that exceeds the chargeable power correction value.

[0003] Patent Document 2 describes an electric vehicle drive control device that includes an electric machine, an electric machine rotational speed detection processing means that detects the electric machine rotational speed, an efficiency calculation processing means that calculates the efficiency of the electric machine, a power limit value calculation processing means that calculates a power limit value corresponding to a battery state, a torque limit value calculation processing means that calculates a torque limit value of the electric machine torque based on the electric machine rotational speed, the efficiency, and the power limit value, and an electric machine target torque calculation processing means that calculates an electric machine target torque that represents a target value of the electric machine torque based on the torque limit value. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-328961 [Patent Document 2] Japanese Patent Application Laid-Open No. 2003-259509 Summary of the Invention [Problem to be solved by the invention]

[0005] The technology disclosed herein aims to efficiently utilize the power of a battery mounted on a vehicle while protecting the battery. [Means for solving the problem]

[0006] A motor control device according to one aspect of the present disclosure is a motor control device provided in a vehicle equipped with a plurality of motors connected to a battery, the motor control device including a processor provided corresponding to each of the plurality of motors, and each of the processors acquires a torque command value, rotation speed, and power loss of the motor corresponding to the processor, derives a first power that is consumed by the motor or output from the motor to the battery when the motor operates to output torque of the torque command value based on the torque command value, the rotation speed, and the power loss, acquires a current value and a voltage value of the motor corresponding to the processor, derives a second power that is consumed by the motor or output from the motor to the battery based on the current value and the voltage value, transmits the second power to another of the processors, acquires the second power derived by the other of the processors from the other of the processors, and transmits the derived second power to the other of the processors. and the second power obtained from the other processor to derive a third power, obtain a fourth power output from or input to the battery, obtain a power limit value of the battery, correct the power limit value based on the third power and the fourth power to derive a control power limit value, allocate the control power limit value to the motor corresponding to the own processor based on the axle torque ratio of the plurality of motors, correct the power value allocated to the motor corresponding to the own processor based on the first power and the second power derived by the own processor to derive an individual power limit value of the battery for that motor, derive a power correction amount for the first power when the first power exceeds the individual power limit value, correct the torque command value of the motor corresponding to the own processor based on the power correction amount, and operate the motor according to the corrected torque command value. [Effects of the Invention]

[0007] According to the technology of the present disclosure, it is possible to efficiently utilize the power of a battery mounted on a vehicle while protecting the battery. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a general configuration of a vehicle equipped with a motor control device according to one embodiment of the disclosed technique. [Figure 2] FIG. 2 is a graph for explaining the control content of the motor ECU 31 during discharging. [Figure 3] FIG. 3 is a graph for explaining the control content of the motor ECU 31 during charging. [Figure 4] FIG. 4 is a graph for explaining a method for deriving the error ΔP1. [Figure 5] FIG. 5 is a graph for explaining a method for deriving the power loss ΔP2. [Figure 6] FIG. 6 is a flowchart for explaining the operation of the ICM1. [Figure 7] FIG. 7 is a flowchart illustrating the operation of the IPU 2. [Figure 8] FIG. 8 is a flowchart (part 1) for explaining the operation of the motor ECU 31. [Figure 9] FIG. 9 is a flowchart (part 2) for explaining the operation of the motor ECU 31. [Figure 10] FIG. 10 is a schematic diagram showing the general configuration of a vehicle 200 which is a modified example of the vehicle 100. As shown in FIG. [Figure 11] FIG. 11 is a flowchart (part 1) for explaining the operation of the motor ECU 36 of the vehicle 200. [Figure 12] FIG. 12 is a flowchart (part 2) for explaining the operation of the motor ECU 36 of the vehicle 200. [Figure 13] FIG. 13 is a schematic diagram (part 1) showing the relationship between the discharge-side power limit value and the control power limit value. [Figure 14] FIG. 14 is a schematic diagram (part 2) showing the relationship between the discharge-side power limit value and the control power limit value. [Figure 15] FIG. 15 is a schematic diagram (part 1) showing the relationship between the charging-side power limit value and the control power limit value. [Figure 16]FIG. 16 is a schematic diagram (part 2) showing the relationship between the charging-side power limit value and the control power limit value. DETAILED DESCRIPTION OF THE INVENTION

[0009] Fig. 1 is a schematic diagram showing the general configuration of a vehicle equipped with a motor control device that is one aspect of the technology disclosed herein. Vehicle 100 shown in Fig. 1 is an automobile having a pair of front wheels and a pair of rear wheels. The technology disclosed herein is not limited to four-wheeled vehicles, but can also be applied to three-wheeled vehicles, two-wheeled vehicles, etc.

[0010] The vehicle 100 includes an ICM (intelligent control module) 1 including a processor (not shown), an IPU (intelligent power unit) 2 including a battery 20 and a processor (not shown), a PCU (power control unit) 3, an accessory 4, a front-wheel drive motor 43 capable of transmitting power to a drive shaft connected to the front wheels, a rear-wheel drive motor 44 capable of transmitting power to a drive shaft connected to the rear wheels, and a generator motor 45 connected to an internal combustion engine (not shown). Two front-wheel drive motors 43 and two rear-wheel drive motors 44 may be provided to provide four motors.

[0011] The dashed arrows in Fig. 1 indicate communication paths. The thick solid lines in Fig. 1 indicate power paths. Below, the front-wheel drive motor 43, the rear-wheel drive motor 44, and the power-generating motor 45 may each be simply referred to as a motor.

[0012] The front-wheel drive motor 43 and the rear-wheel drive motor 44 operate as electric motors using power supplied from the battery 20 to generate power for propelling the vehicle 100. The torque generated by the front-wheel drive motor 43 and the rear-wheel drive motor 44 is transmitted to the front wheels and rear wheels via the drive shafts. The front-wheel drive motor 43 and the rear-wheel drive motor 44 can each operate as a generator when braking the vehicle 100.

[0013] The electric power generated by the generator motor 45 is used to drive the front wheel drive motor 43 and the rear wheel drive motor 44, and to charge the battery 20. The front wheel drive motor 43, the rear wheel drive motor 44, and the generator motor 45 are each configured by, for example, a PMSM (Permanent Magnet Synchronous Motor) such as a three-phase AC IPM (Interior Permanent Magnet).

[0014] The battery 20 has, for example, a plurality of storage cells connected in series, and supplies a high voltage of, for example, 100 to 200 V. The storage cells are, for example, lithium ion batteries, nickel-metal hydride batteries, or all-solid-state batteries.

[0015] The IPU 2 is provided with sensors that detect the voltage, current, and temperature of the battery 20. Based on information from these sensors, the processor of the IPU 2 can derive the power output from or input to the battery 20 (hereinafter referred to as BAT power PB).

[0016] The processor of the IPU 2 also determines the state of the battery 20 (SOC (State Of Charge) and the like) based on the information from these sensors, reads out information on the power limit value determined according to the state from the memory, and transmits it to the motor ECU 31.

[0017] The power limit value of the battery 20 includes a discharge-side power limit value, which is the upper limit of output when power is output from the battery 20 (when discharging), and a charge-side power limit value, which is the upper limit of input when power is input to the battery 20 (when charging). The relationship between the state of the battery 20 and the power limit value is determined experimentally or stored in a memory or the like according to the usage conditions and specifications of the vehicle and the battery.

[0018] The PCU 3 comprises a PDU (power drive unit) 33 connected to the front wheel drive motor 43, a PDU 34 connected to the rear wheel drive motor 44, a PDU 35 connected to the generator motor 45, a VCU (voltage control unit) 32 connected to the PDU 33, PDU 34, and PDU 35, and a motor ECU (Electronic Control Unit) 31 that controls all of these.

[0019] The motor ECU 31 includes a processor such as a CPU (Central Processing Unit) and a memory. The motor ECU 31 may include a single processor or multiple processors. The processor is hardware that performs various processes by executing programs, and is specifically configured as an electric circuit.

[0020] When the front wheel drive motor 43 and the rear wheel drive motor 44 operate as electric motors, the VCU 32 boosts the DC voltage from the battery 20 and supplies it to the PDU 33 and the PDU 34. When the front wheel drive motor 43 and the rear wheel drive motor 44 operate as generators, the VCU 32 steps down the DC voltage supplied from the PDU 33 and the PDU 34 and inputs it to the battery 20. When the generator motor 45 is generating power, the VCU 32 steps down the DC voltage supplied from the PDU 35 and inputs it to the battery 20. The VCU 32 performs the step-up and step-down by controlling a built-in switching element. For this reason, power loss due to switching may occur in the VCU 32.

[0021] When the front wheel drive motor 43 operates as an electric motor, the PDU 33 converts the output voltage of the VCU 32 into AC. When braking the vehicle 100, the PDU 33 converts the AC generated by the front wheel drive motor 43 into DC.

[0022] When the rear wheel drive motor 44 operates as an electric motor, the PDU 34 converts the output voltage of the VCU 32 into AC. When the vehicle 100 is braking, the PDU 34 converts the AC generated by the rear wheel drive motor 44 into DC.

[0023] When the generator motor 45 is generating electricity, the PDU 35 converts the AC power generated by the generator motor 45 into DC power. Each of the PDUs 33, 34, and 35 converts between AC and DC power by controlling switching elements. Therefore, each of the PDUs 33, 34, and 35 may experience power loss due to switching.

[0024] PDU 33, PDU 34, and PDU 35 each perform vector control, and generate a d-axis current command value Id and a q-axis current command value Iq based on a d-axis voltage command value Vd, a q-axis voltage command value Vq, etc. input from the motor ECU 31, and supply three-phase AC currents based on these to the motor coils.

[0025] A rotation speed sensor that detects the rotation speed is provided to each of the front wheel drive motor 43, the rear wheel drive motor 44, and the generator motor 45. Information on the rotation speed of each motor is transmitted to the motor ECU 31.

[0026] Further, a current sensor that detects three-phase AC current flowing through the coil is provided in each of the front-wheel drive motor 43, the rear-wheel drive motor 44, and the generator motor 45. Information on the three-phase AC current of each motor is transmitted to the motor ECU 31.

[0027] The electric power consumed by a motor while the motor is operating or the electric power output from the motor to the battery 20 will be referred to as motor power. Hereinafter, the motor power of the front wheel drive motor 43 will be referred to as motor power P43, the motor power of the rear wheel drive motor 44 will be referred to as motor power P44, and the motor power of the generator motor 45 will be referred to as motor power P45. The motor power P45 is the electric power output from the generator motor 45 to the battery 20.

[0028] The motor power can be derived by multiplying the d-axis current value Id and the q-axis current value Iq obtained by dq conversion of the three-phase AC current detected by a current sensor provided in the motor by the d-axis voltage command value Vd and the q-axis voltage command value Vq of the motor (Id×Vd+Iq×Vq).

[0029] Motor power P43 and motor power P44 are each positive values ​​when they are power consumed by the motor. Motor power P43 and motor power P44 are each negative values ​​when they are power output from the motor to battery 20 (i.e., power generated). Motor power P45 is power output from the motor to battery 20, so it is negative.

[0030] For example, assume that the front wheel drive motor 43 and the rear wheel drive motor 44 are operating as electric motors and the generator motor 45 is generating electricity. In this case, the power output from the battery 20 is calculated by adding the power loss ΔP2 (switching loss in each PDU, switching loss in the VCU 32, loss in the auxiliary equipment 4, etc.) in the power path from the battery 20 to each motor to the value obtained by calculating {P43+P44+(-P45)}.

[0031] Also, assume that the front wheel drive motor 43 and the rear wheel drive motor 44 operate as generators, and the generator motor 45 generates electricity. In this case, the value obtained by subtracting the power loss ΔP2 from the absolute value of the value obtained by the calculation of {(-P43) + (-P44) + (-P45)} is input to the battery 20.

[0032] The processor of the motor ECU 31 controls the motor power P43, the motor power P44, and the motor power P45 so that the BAT power PB does not exceed the above-mentioned power limit value. However, since information about the BAT power PB is sent from the IPU 2 to the motor ECU 31 via a communication line, a delay occurs. In other words, the processor of the motor ECU 31 cannot monitor the BAT power PB in real time.

[0033] Therefore, in this embodiment, when the processor of the motor ECU 31 receives the torque command value of each motor from the ICM 1, it obtains the rotation speed of each motor from the rotation speed sensor and obtains the motor power loss (motor loss) determined by the state of each motor from memory. The motor loss is experimentally determined and stored in advance in the memory of the motor ECU 31.

[0034] Based on the torque command value, rotation speed, and motor loss obtained for each motor, the processor of the motor ECU 31 derives the expected power that will be consumed by each motor or output from each motor to the battery 20 when each motor operates to output the torque of the torque command value.

[0035] in particular, (torque indication value + correction torque in the motor) x rotation speed + motor loss The expected power of each motor is calculated by the above calculation. The correction torque in the motor is a value experimentally determined for each motor, or a value corrected in real time by feedback from the motor's rotation speed. The motor loss is a positive value when the motor is consuming power, and a negative value when the motor is generating power.

[0036] The expected power consumed by the front wheel drive motor 43 or the expected power output from the front wheel drive motor 43 to the battery 20 is referred to as expected power Pf. The expected power consumed by the rear wheel drive motor 44 or the expected power output from the rear wheel drive motor 44 to the battery 20 is referred to as expected power Pr. The expected power output from the generator motor 45 to the battery 20 is referred to as expected power Pg. The sum of the expected power Pf, the expected power Pr, and the expected power Pg is referred to as total expected power PE.

[0037] The expected power Pf and the expected power Pr are each positive values ​​when they are power consumed by the motor. The expected power Pf and the expected power Pr are each negative values ​​when they are power output from the motor to the battery 20, except when power is being discarded. The expected power Pg is power output from the motor to the battery 20, and therefore is a negative value when power is being discarded.

[0038] The total expected power PE is calculated by (Pf+Pr+(-Pg)) when the front wheel drive motor 43 and the rear wheel drive motor 44 are operated as electric motors. When the front wheel drive motor 43 and the rear wheel drive motor 44 are operated as generators, the total expected power PE is calculated as the absolute value of the value obtained by the calculation ((-Pf)+(-Pr)+(-Pg)).

[0039] Figure 2 is a graph illustrating the control content of the motor ECU 31 during discharge. For simplicity, in Figure 2, the torque command values ​​for the rear-wheel drive motor 44 and the generator motor 45 are assumed to be 0. As mentioned above, the BAT power PB cannot be monitored in real time. For this reason, the processor of the motor ECU 31 uses the total expected power PE and the control power limit value to control the BAT power PB so that it does not exceed the discharge-side power limit value.

[0040] Specifically, the processor of the motor ECU 31 derives a control power limit value that is basically smaller than the discharge power limit value (a value obtained by subtracting a discharge correction amount, described later, from the discharge power limit value), although this may change depending on the error. If the total expected power PE derived at the time of acquiring the torque command value from the ICM1 ​​exceeds this control power limit value, the processor of the motor ECU 31 corrects the total expected power PE to the control power limit value (see the downward arrow in the upper part of Figure 2).

[0041] The processor of the motor ECU 31 converts the corrected total expected power PE into a torque command value, taking into account the motor loss of each motor. As shown in the lower part of Figure 2, the converted torque command value is changed to a value smaller than the original torque command value (see the downward arrow in the lower part of Figure 2). The processor of the motor ECU 31 drives each motor so that the torque of this converted torque command value is output. As a result, the BAT power PB changes as shown in the upper part of Figure 2.

[0042] Assuming that there is no error in the motor loss of each motor, when each motor is driven to generate a torque of the converted torque command value shown in Figure 2, the value consumed from battery 20 is the corrected total expected power PE plus the power loss ΔP2 that occurs in the power path from battery 20 to each motor.

[0043] However, in reality, motor loss can contain errors. Regarding the motor loss error ΔP1 for the entire three motors, the direction in which loss increases is taken as a positive value, and the direction in which loss decreases is taken as a negative value.

[0044] When the error ΔP1 is a positive value, the control power limit value plus the error ΔP1 and the power loss ΔP2 becomes the upper limit of the power output from the battery 20. Therefore, by making the discharge correction amount equal to the sum of the error ΔP1 (positive value) and the power loss ΔP2, the power output from the battery 20 will not exceed the discharge-side power limit value.

[0045] This makes it possible to prevent the BAT power PB from exceeding the discharge-side power limit value while keeping the upper limit of the BAT power PB as close as possible to the discharge-side power limit value, thereby protecting the battery 20 and enabling efficient use of the power of the battery 20.

[0046] If the error ΔP1 is a negative value, the power loss ΔP2 is added to the control power limit value, and the absolute value of the error ΔP1 is further subtracted from it, which becomes the upper limit of the power output from the battery 20. In this case, too, by making the discharge correction amount equal to the sum of the error ΔP1 (negative value) and the power loss ΔP2, the power output from the battery 20 will not exceed the discharge-side power limit value.

[0047] This makes it possible to prevent the BAT power PB from exceeding the discharge-side power limit value while keeping the upper limit of the BAT power PB as close as possible to the discharge-side power limit value, thereby protecting the battery 20 and enabling efficient use of the power of the battery 20.

[0048] Figure 3 is a graph for explaining the control content of the motor ECU 31 during charging on the negative side, when the discharging side in Figure 2 is considered to be the positive side. During charging (when the front wheel drive motor 43 and the rear wheel drive motor 44 are in regenerative operation), the processor of the motor ECU 31 derives a value greater than the charging side power limit value (a value obtained by adding a charging correction amount to the charging side power limit value) as the control power limit value.

[0049] If the total expected power PE calculated at the time of acquiring the torque command value from ICM1 ​​exceeds this control power limit value, the processor of motor ECU 31 corrects the total expected power PE to the control power limit value (see the downward arrow in Figure 3). The processor of motor ECU 31 converts the corrected total expected power PE into a torque command value taking into account the motor loss of each motor.

[0050] When the error ΔP1 is a positive value, the power obtained by subtracting the error ΔP1 from the control power limit value and then subtracting the power loss ΔP2 becomes the upper limit of the power input to the battery 20. Therefore, by making the difference (charging correction amount) between the control power limit value and the charge-side power limit value in Fig. 3 equal to the sum of the error ΔP1 and the power loss ΔP2, it is possible to prevent the power input to the battery 20 from exceeding the charge-side power limit value.

[0051] This makes it possible to prevent the BAT power PB from exceeding the charge-side power limit value while keeping the upper limit of the BAT power PB as close as possible to the charge-side power limit value, thereby enabling protection of the battery 20 and efficient charging of the battery 20.

[0052] If the error ΔP1 is a negative value, the error ΔP1 (absolute value) is added to the control power limit value, and the power loss ΔP2 is further subtracted from it, resulting in the upper limit of power input to the battery 20. Therefore, by making the charging correction amount equal to the sum of the error ΔP1 (negative value) and the power loss ΔP2, it is possible to prevent the power input to the battery 20 from exceeding the charging-side power limit value.

[0053] This makes it possible to prevent the BAT power PB from exceeding the charge-side power limit value while keeping the upper limit of the BAT power PB as close as possible to the charge-side power limit value, thereby enabling protection of the battery 20 and efficient charging of the battery 20.

[0054] In this way, the control power limit value is derived by correcting the power limit value based on the motor loss error ΔP1 across all three motors and the power loss ΔP2. Because the error ΔP1 and the power loss ΔP2 can vary depending on the situation, it is difficult to determine them experimentally in advance.

[0055] Therefore, the processor of the motor ECU 31 derives the error ΔP1 based on the total motor power PM, which is the sum of the motor powers of the individual motors, and the total anticipated power PE. The processor of the motor ECU 31 also derives the power loss ΔP2 based on the total motor power PM and the BAT power PB.

[0056] In other words, the processor of the motor ECU 31 corrects the power limit value based on the total motor power PM, the total expected power PE, and the BAT power PB, and derives the control power limit value.

[0057] FIG. 4 is a graph illustrating a method for deriving the error ΔP1. FIG. 4 shows an example of the time variation of the total expected power PE and the total motor power PM. The total motor power PM is the value when each motor operates and outputs torque according to the torque command value immediately before the timing at which the total expected power PE is derived. For this reason, there is a time lag between the total expected power PE and the total motor power PM.

[0058] The processor of the motor ECU 31 eliminates the time difference between the total anticipated power PE and the total motor power PM, and then calculates the difference between the total anticipated power PE and the total motor power PM to derive the error ΔP1.

[0059] First, if the calculated total expected power PE exceeds the control power limit value calculated when the previous torque command value was received, the processor of the motor ECU 31 corrects the total expected power PE to the control power limit value. In the example of Fig. 4, the portion PX indicated by the dashed line in the figure is corrected to the control power limit value.

[0060] Next, the processor of the motor ECU 31 delays the corrected total expected power PE using a ring buffer and a low-pass filter (see the white arrow in the figure).

[0061] Next, the processor of the motor ECU 31 derives the difference between the delayed total expected power PE' and the total motor power PM as the motor loss error ΔP1 for all three motors. The error ΔP1 can also be derived during charging in a similar manner.

[0062] Fig. 5 is a graph for explaining a method for deriving the power loss ΔP2. Fig. 5 shows an example of changes over time in the total motor power PM and the BAT power PB. The BAT power PB arrives at the motor ECU 31 with a delay from the timing at which the total motor power PM is derived. For this reason, there is a time lag between the BAT power PB and the total motor power PM.

[0063] The processor of the motor ECU 31 eliminates the time difference between the BAT power PB and the total motor power PM, and then calculates the difference between the BAT power PB and the total motor power PM to derive the power loss ΔP2.

[0064] First, the processor of the motor ECU 31 delays the total motor power PM using a ring buffer and a low-pass filter (see the white arrow in the figure). The processor of the motor ECU 31 derives the difference (absolute value) between the delayed total motor power PM' and the BAT power PB as the power loss ΔP2. The power loss ΔP2 can also be derived during charging using a similar method.

[0065] FIG. 6 is a flowchart for explaining the operation of the processor of the ICM1.

[0066] The processor of ICM1 ​​derives a driving force limit value from the states of the three motors and the battery 20 (step S11). Next, the processor of ICM1 ​​acquires a driver request based on information such as a shift operation, an accelerator pedal operation, and a brake operation, and derives a vehicle required driving force from the driver request and the driving force limit value derived in step S11 (step S12).

[0067] Next, the processor of ICM1 ​​derives the distribution of driving force between the front and rear wheels (step S13). Next, the processor of ICM1 ​​determines the final driving force of the front wheel drive motor 43, the final driving force of the rear wheel drive motor 44, and the final driving force of the internal combustion engine (step S14).

[0068] Next, the processor of the ICM 1 derives a final torque command for each motor (step S15), and transmits the torque command value for each motor to the motor ECU 31 (step S16).

[0069] FIG. 7 is a flowchart for explaining the operation of the processor of the IPU 2.

[0070] The processor of the IPU 2 acquires the current, voltage, and temperature of the battery 20 from sensors included in the IPU 2 (step S21). Next, the processor of the IPU 2 derives the battery state such as the SOC, resistance value, and heat generation amount of the battery 20 (step S22).

[0071] Next, based on the derived battery state, the processor of the IPU 2 obtains the power limit value of the battery 20 corresponding to that battery state from the map stored in the memory (step S23).

[0072] Next, the processor of the IPU 2 derives the BAT power PB, which is the power output from or input to the battery 20, based on the current and voltage acquired in step S21 (step S24).

[0073] Next, the processor of the IPU 2 transmits the power limit value acquired in step S23 and the BAT power PB derived in step S24 to the motor ECU 31 (step S25).

[0074] 8 and 9 are flowcharts for explaining the operation of the motor ECU 31. The processor of the motor ECU 31 receives the torque command value of each motor from the ICM 1 (step S31), and receives the power limit value and the BAT power PB from the IPU 2 (step S32). The processor of the motor ECU 31 also acquires the rotation speed of each motor from the rotation speed sensor provided in each motor (step S33).

[0075] The processor of the motor ECU 31 also acquires three-phase AC current values ​​from current sensors provided in each motor. Based on the d-axis voltage command value and q-axis voltage command value of each motor and the acquired three-phase AC current values ​​of each motor, the processor of the motor ECU 31 derives motor power P43 of the front-wheel drive motor 43, motor power P44 of the rear-wheel drive motor 44, and motor power P45 of the generator motor 45, and adds these together to derive total motor power PM (step S34).

[0076] In addition, the processor of the motor ECU 31 obtains from the memory the motor loss determined by the combination of the torque command value received in step S31 and the rotation speed obtained in step S33, and derives the expected power for each motor based on the motor loss, torque command value, and rotation speed (step S35).

[0077] After step S35, the processor of the motor ECU 31 adds up the expected powers of the respective motors to derive a total expected power PE (step S36). The processor of the motor ECU 31 derives a correction amount (discharge correction amount or charge correction amount) for the power limit value received in step S32 using the method described above, based on the BAT power PB received in step S32, the total motor power PM derived in step S34, and the total expected power PE derived in step S36 (step S37).

[0078] After step S37, the processor of the motor ECU 31 derives a control power limit value from the power limit value received in step S32 and the correction amount derived in step S37 (step S38).

[0079] Next, the processor of the motor ECU 31 derives the power correction amount of the total expected power PE (the difference between the total expected power PE and the control power limit value when the total expected power PE exceeds the control power limit value) from the control power limit value derived in step S38 and the total expected power PE derived in step S36 (step S39).

[0080] If the total expected power PE is the value to be input to the battery 20 (step S40: charging), the processor of the motor ECU 31 performs a correction to reduce the expected power Pg of the generator motor 45 by the amount of the power correction amount derived in step S39 (step S40). In other words, by reducing the power that is expected to be generated by the generator motor 45, the total expected power PE is controlled so as not to exceed the control power limit value.

[0081] When the total expected power PE is the value output from the battery 20 (step S40: Discharge), the processor of the motor ECU 31 acquires the average rotation speed of the front wheels, the average rotation speed of the rear wheels, and the motor rotation speed.

[0082] If the average rotation speed of the front wheels is greater than the average rotation speed of the rear wheels by a threshold value or more (step S45: YES), the processor of the motor ECU 31 performs a correction to reduce the expected power Pf of the front-wheel drive motor 43 by the amount of the power correction amount calculated in step S39 (step S46). In other words, by reducing the power expected to be consumed by the front-wheel drive motor 43, control is performed so that the total expected power PE does not exceed the control power limit value. The determination in step S45 is YES when, for example, only the front wheels are slipping out of the front and rear wheels.

[0083] If the average rotation speed of the front wheels is not higher than the average rotation speed of the rear wheels by the threshold or more (step S45: NO), the processor of the motor ECU 31 determines whether the average rotation speed of the rear wheels is higher than the average rotation speed of the front wheels by the threshold or more (step S47).

[0084] If the determination in step S47 is YES, the processor of the motor ECU 31 performs a correction to reduce the expected power Pr of the rear-wheel drive motor 44 by the amount of the power correction amount calculated in step S39 (step S48). In other words, by reducing the power expected to be consumed by the rear-wheel drive motor 44, control is performed so that the total expected power PE does not exceed the control power limit value. The determination in step S47 is YES, for example, when only the rear wheels are slipping out of the front and rear wheels.

[0085] If the determination in step S47 is NO, the processor of the motor ECU 31 distributes the power correction amount derived in step S39 to the front wheel drive motor 43 and the rear wheel drive motor 44 in accordance with the power ratio between the expected power Pf of the front wheel drive motor 43 and the expected power Pr of the rear wheel drive motor 44. Then, the processor of the motor ECU 31 corrects the expected power Pf of the front wheel drive motor 43 to decrease it by the amount of the power correction amount distributed to the front wheel drive motor 43, and corrects the expected power Pr of the rear wheel drive motor 44 to decrease it by the amount of the power correction amount distributed to the rear wheel drive motor 44 (step S49).

[0086] After step S41, step S46, step S48, or step S49, the processor of the motor ECU 31 converts the corrected expected power of each motor into torque, taking into account the motor loss of that motor (step S42).

[0087] Next, the processor of the motor ECU 31 corrects the torque command value of each motor received in step S31 so that the torque command value matches the converted torque obtained in step S42 (step S43).

[0088] Thereafter, the processor of the motor ECU 31 controls the driving of each motor in accordance with the torque command value corrected in step S43 (step S44).

[0089] 8 and 9 may be performed in any order as long as there is no contradiction. For example, step S35 may be performed after step S31 and step S33, and may be performed in parallel with step S32 or step S34, or before step S32 or step S34. Furthermore, steps S31 to S34 may be performed in parallel, or the order may be changed arbitrarily.

[0090] According to the vehicle 100 configured as described above, the battery 20 is protected by preventing over-discharging and over-charging, while the power of the battery 20 is consumed without waste and the battery 20 can be charged efficiently.

[0091] Although the vehicle 100 is assumed to have three motors, the technology of the present disclosure can be applied even to a configuration in which any one of the three motors is omitted, or a configuration in which any one of the front wheel drive motor 43 and the rear wheel drive motor 44 and the generator motor 45 are omitted.

[0092] Fig. 10 is a schematic diagram showing the general configuration of vehicle 200, which is a modified example of vehicle 100. Vehicle 200 has a configuration in which VCU 32, PDU 35, and generator motor 45 are eliminated from vehicle 100, and PCU 3 is divided into PCU 3A and PCU 3B. The dashed arrows in Fig. 10 indicate communication paths. The thick solid lines in Fig. 10 indicate power paths.

[0093] The PCU 3A includes a PDU 33 and a motor ECU 36 that controls the PDU 33. The PCU 3B includes a PDU 34 and a motor ECU 37 that controls the PDU 34. The motor ECU 36 and the motor ECU 37 are configured to be able to communicate with the ICM 1 and the IPU 2, respectively. The motor ECU 36 and the motor ECU 37 are configured to be able to communicate with each other.

[0094] It should be noted that the PCU 3A and the PCU 3B do not have to be physically separated, but even in this case, the motor ECU 36 and the motor ECU 37 are provided separately.

[0095] 11 and 12 are flowcharts for explaining the operation of the motor ECU 36 of the vehicle 200. The operation of the motor ECU 37 of the vehicle 200 is the same as the operation of the motor ECU 36, and therefore a description thereof will be omitted.

[0096] In the following, the front-wheel drive motor 43 connected to the PDU 33 controlled by the motor ECU 36 will be referred to as the "own motor." Regarding the operation of the motor ECU 37, the "own motor" in the following description can be read as the rear-wheel drive motor 44.

[0097] The processor of the motor ECU 36 receives the torque command value of its own motor from the ICM 1 (step S51), and receives the power limit value and the BAT power PB from the IPU 2 (step S52). The processor of the motor ECU 36 also acquires the rotation speed of its own motor from a rotation speed sensor provided in its own motor (step S53).

[0098] The processor of the motor ECU 36 also acquires three-phase AC current values ​​from a current sensor provided in the motor itself. The processor of the motor ECU 36 derives the motor power of the motor itself (the same as the motor power P43 described above) based on the d-axis voltage command value and q-axis voltage command value of the motor itself and the acquired three-phase AC current value of the motor itself, and transmits the derived motor power to another motor ECU (motor ECU 37) (step S54). The processor of the motor ECU 37 also transmits the motor power of the rear-wheel drive motor 44 derived by similar processing to the motor ECU 36.

[0099] The processor of the motor ECU 36 receives the motor power (same as the motor power P44 described above) of the rear wheel drive motor 44 transmitted from the motor ECU 37 (step S55).

[0100] The processor of the motor ECU 36 obtains from memory the motor loss of the motor itself, which is determined by the combination of the torque command value received in step S51 and the rotation speed obtained in step S53, and derives the expected power of the motor itself (the same as the expected power Pf described above) based on the obtained motor loss, torque command value, and rotation speed (step S56).

[0101] Next, the processor of the motor ECU 36 sums the motor power of its own motor derived in step S54 and the motor power of the other motor (rear-wheel drive motor 44) received in step S55 to derive the total motor power PM. The method of deriving the total motor power PM is as described above. Then, the processor of the motor ECU 36 derives the correction amount (discharge correction amount or charge correction amount) for the power limit value received in step S52 based on the derived total motor power PM and the BAT power PB received in step S52 (step S57).

[0102] In step S57, the processor of motor ECU 36 delays total motor power PM, as described in Figure 5, and derives the difference between delayed total motor power PM' and BAT power PB as the correction amount for the power limit value. This difference is the power loss occurring in the power paths from battery 20 to each motor, and will be referred to as power loss ΔP3.

[0103] Next, the processor of the motor ECU 36 derives a control power limit value for the two motors as a whole from the power limit value received in step S52 and the correction amount derived in step S57 (step S58).

[0104] Figures 13 and 14 are schematic diagrams showing the relationship between the discharge-side power limit value and the control power limit value, and Figures 15 and 16 are schematic diagrams showing the relationship between the charge-side power limit value and the control power limit value.

[0105] In step S58, the processor of the motor ECU 36 derives the value obtained by subtracting the correction amount (power loss ΔP3) derived in step S57 from the discharge-side power limit value as the discharge-side control power limit value (see Figures 13 and 14).

[0106] In step S58, the processor of the motor ECU 36 derives the charging-side control power limit value by adding the correction amount (power loss ΔP3) derived in step S57 to the charging-side power limit value (see FIGS. 15 and 16).

[0107] Next, the processor of the motor ECU 36 allocates the control power limit value derived in step S58 to each motor based on the axle torque ratio between the front wheel drive motor 43 and the rear wheel drive motor 44, and derives the allocated power value for that motor (see FIGS. 13 and 14) (step S59). For example, if the axle torque ratio between the front wheel drive motor 43 and the rear wheel drive motor 44 is 2:1, 2 / 3 of the control power limit value is derived as the allocated power value for that motor.

[0108] Next, the processor of the motor ECU 36 derives the error in the motor loss of the own motor based on the expected power Pf of the own motor derived in step S56 and the motor power P43 of the own motor derived in step S54 (step S60).

[0109] In step S60, as explained in Fig. 4, if the expected power Pf of the motor exceeds the immediately preceding individual power limit value of the motor (described in detail later), the processor of the motor ECU 36 corrects the expected power Pf to this individual power limit value, delays the corrected expected power Pf, and derives the difference between the delayed expected power Pf' and the motor power P43 of the motor as the motor loss error ΔP4 of the motor. For the error ΔP4, a positive value indicates an increase in loss, and a negative value indicates a decrease in loss.

[0110] Next, the processor of the motor ECU 36 derives an individual power limit value corresponding to its own motor based on the distribution power value derived in step S59 and the error ΔP4 derived in step S60 (step S61).

[0111] In step S61, if the error ΔP4 is a positive value (the loss of the motor itself is greater than expected), the value obtained by subtracting the error ΔP4 (positive value) from the allocated power value of the front wheel drive motor 43 is derived as the individual power limit value 43A of the front wheel drive motor 43, as shown in Figure 13.

[0112] When the error ΔP4 is a negative value (loss of the motor itself is less than expected), as shown in Figure 14, the value obtained by subtracting the error ΔP4 (negative value) from the allocated power value of the front wheel drive motor 43, that is, the value obtained by adding the absolute value of the error ΔP4 to the allocated power value of the front wheel drive motor 43, is derived as the individual power limit value 43A of the front wheel drive motor 43 (see Figure 14).

[0113] The processes of steps S51 to S61 are also performed by the processor of the motor ECU 37. In Figures 13 and 14, the error derived by the processor of the motor ECU 37 in the process of step S60 is indicated as error ΔP5.

[0114] The error ΔP5 is derived as the difference between the expected power Pr' obtained by delaying the expected power Pr of the rear wheel drive motor 44 and the motor power P44 of the rear wheel drive motor 44. The error ΔP5 is set to a positive value when the loss increases, and a negative value when the loss decreases.

[0115] If the error ΔP5 is a positive value, as shown in FIG. 13, the value obtained by subtracting the error ΔP5 (positive value) from the allocated power value of the rear wheel drive motor 44 is derived as the individual power limit value 44A of the rear wheel drive motor 44.

[0116] If the error ΔP5 is a negative value, as shown in Figure 14, the value obtained by subtracting the error ΔP5 (negative value) from the allocated power value of the rear wheel drive motor 44, that is, the value obtained by adding the absolute value of the error ΔP5 to the allocated power value of the rear wheel drive motor 44, is derived as the individual power limit value 44A of the rear wheel drive motor 44.

[0117] After step S61, the processor of the motor ECU 36 derives a power correction amount for the expected power of the motor (the difference between the expected power and the individual power limit value when the expected power exceeds the individual power limit value) from the individual power limit value derived in step S61 and the expected power of the motor derived in step S56 (step S62).

[0118] After step S62, the processor of the motor ECU 36 performs a correction to reduce the expected power of the motor by the amount of the power correction amount derived in step S62 (step S63). That is, the processor controls the expected power of the motor so that it does not exceed the individual power limit value.

[0119] Next, the processor of the motor ECU 36 converts the corrected expected electric power of the motor into torque, taking into account the motor loss of the motor (step S64).

[0120] Next, the processor of the motor ECU 36 corrects the torque command value of its own motor received in step S51 so that the torque command value of its own motor matches the converted torque obtained in step S64 (step S65).

[0121] Thereafter, the processor of the motor ECU 36 controls the motor to be driven in accordance with the torque command value corrected in step S65 (step S66).

[0122] 13, the power consumption of the front-wheel drive motor 43 operating as an electric motor in accordance with the corrected torque command value is limited to the value obtained by adding the error ΔP4 to the individual power limit value 43A (= the power distribution value of the front-wheel drive motor 43).Furthermore, the power consumption of the rear-wheel drive motor 44 operating as an electric motor in accordance with the corrected torque command value is limited to the value obtained by adding the error ΔP5 to the individual power limit value 44A (= the power distribution value of the rear-wheel drive motor 44).When the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate in accordance with the corrected torque command value, a power loss ΔP3 occurs.

[0123] Therefore, the power consumed from the battery 20 when the front wheel drive motor 43 and the rear wheel drive motor 44 are operated according to the corrected torque command value is the sum of the allocated power value of the front wheel drive motor 43, the allocated power value of the rear wheel drive motor 44, and the power loss ΔP3, and this sum matches the power limit value on the discharge side.

[0124] Therefore, by correcting the torque command value of the front wheel drive motor 43 so that the expected power of the front wheel drive motor 43 does not exceed the individual power limit value 43A, and by correcting the torque command value of the rear wheel drive motor 44 so that the expected power of the rear wheel drive motor 44 does not exceed the individual power limit value 44A, the power output from the battery 20 can be kept below the power limit value on the discharge side.

[0125] In the example shown in FIG. 14, the power consumption of the front-wheel drive motor 43, which operates as an electric motor in accordance with the corrected torque command value, is limited to the value obtained by subtracting the error ΔP4 from the individual power limit value 43A (= the allocated power value of the front-wheel drive motor 43). Similarly, the power consumption of the rear-wheel drive motor 44, which operates as an electric motor in accordance with the corrected torque command value, is limited to the value obtained by subtracting the error ΔP5 from the individual power limit value 44A (= the allocated power value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate in accordance with the corrected torque command value, a power loss ΔP3 occurs. Therefore, as in the case of FIG. 13, the power output from the battery 20 can be limited to or below the power limit value on the discharge side.

[0126] 15, the power generated by the front-wheel drive motor 43 operating as a generator in accordance with the corrected torque command value has an upper limit of the value obtained by subtracting the error ΔP4 from the individual power limit value 43A (= the power distribution value of the front-wheel drive motor 43). Similarly, the power generated by the rear-wheel drive motor 44 operating as a generator in accordance with the corrected torque command value has an upper limit of the value obtained by subtracting the error ΔP5 from the individual power limit value 44A (= the power distribution value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate in accordance with the corrected torque command value, a power loss ΔP3 occurs.

[0127] Therefore, when the front wheel drive motor 43 and the rear wheel drive motor 44 are operated according to the corrected torque command value, the power input to the battery 20 is the sum of the allocated power value of the front wheel drive motor and the allocated power value of the rear wheel drive motor minus the power loss ΔP3, and this value coincides with the power limit value on the charging side.

[0128] Therefore, by correcting the torque command value of the front wheel drive motor 43 so that the expected power of the front wheel drive motor 43 does not exceed the individual power limit value 43A, and by correcting the torque command value of the rear wheel drive motor 44 so that the expected power of the rear wheel drive motor 44 does not exceed the individual power limit value 44A, the power input to the battery 20 can be kept below the power limit value on the charging side.

[0129] In the example shown in FIG. 16, the power generated by the front-wheel drive motor 43, which operates as a generator in accordance with the corrected torque command value, has an upper limit of the value obtained by adding an error ΔP4 to the individual power limit value 43A (= the power distribution value of the front-wheel drive motor 43). Similarly, the power generated by the rear-wheel drive motor 44, which operates as a generator in accordance with the corrected torque command value, has an upper limit of the value obtained by adding an error ΔP5 to the individual power limit value 44A (= the power distribution value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate in accordance with the corrected torque command value, a power loss ΔP3 occurs. Therefore, as in the case of FIG. 15, the power input to the battery 20 can be kept below the power limit value on the charging side.

[0130] As described above, according to vehicle 200, the motor ECUs (motor ECU 36, motor ECU 37) provided for each motor can derive an individual power limit value for the corresponding motor. In this way, an individual power limit value and expected power can be derived for each motor, and the torque command value can be corrected based on the individual power limit value and expected power. Therefore, for example, compared to a configuration in which motor ECU 36 and motor ECU 37 are replaced by a single ECU, torque correction for each motor can be performed more quickly.

[0131] This specification describes at least the following items. Note that the components in parentheses correspond to those in the above-described embodiment, but are not limited to these.

[0132] (1) A motor control device (a concept including PCU3A and PCU3B) provided in a vehicle (vehicle 100) equipped with a plurality of motors (front wheel drive motor 43, rear wheel drive motor 44) connected to a battery, processors (motor ECU 36, motor ECU 37) provided corresponding to each of the plurality of motors; Each of said processors: acquires a torque command value, a rotation speed, and a power loss of the motor corresponding to the own processor, and derives a first power (anticipated power Pf or anticipated power Pr) that will be consumed by the motor or output from the motor to the battery when the motor operates to output a torque of the torque command value based on the torque command value, the rotation speed, and the power loss; acquires a current value and a voltage value of the motor corresponding to the own processor, and derives a second power (motor power P43 or motor power P44) consumed by the motor or output from the motor to the battery based on the current value and the voltage value; transmitting the second power to another of the processors; obtaining from the other processor the second power derived by that processor; deriving a third power (total motor power PM) by adding up the derived second power and the second power obtained from the other processor; Acquire a fourth power (BAT power PB) output from or input to the battery; Obtain the power limit value of the battery; deriving a control power limit value by correcting the power limit value based on the third power and the fourth power; allocating the control power limit value to the motors corresponding to the own processor based on axle torque ratios of the plurality of motors; correcting a power value (distributed power value) allocated to the motor corresponding to the own processor based on the first power and the second power derived by the own processor to derive an individual power limit value of the battery for that motor, and deriving a power correction amount for the first power when the first power exceeds the individual power limit value; The motor control device corrects the torque command value of the motor corresponding to its own processor based on the power correction amount, and operates the motor in accordance with the corrected torque command value.

[0133] (2) The motor control device according to (1), Each of said processors: If the first power derived based on the torque command value exceeds the individual power limit value immediately before the torque command value is acquired, the first power is corrected to the individual power limit value; A motor control device that corrects the allocated power value based on a delayed version of the corrected first power (prospective power Pf' or prospective power Pr') and the second power (motor power P43 or motor power P44) derived by its own processor.

[0134] (3) The motor control device according to (2), Each of said processors: deriving a difference value (error ΔP4 or error ΔP5) between the delayed first power after correction and the second power derived by the own processor; The motor control device corrects the allocated power value based on the difference value to derive a new individual power limit value.

[0135] (4) The motor control device according to (3), Each of the processors derives the individual power limit value by subtracting the difference value from the allocated power value or by adding the difference value to the allocated power value. [Explanation of symbols]

[0136] 1 ICM 2 IPU 3,3A,3B PCU 4 Auxiliary equipment 20 Battery 31, 36, 37 Motor ECU 32 VCU 33, 34, 35 PDUs 43 Front wheel drive motor 44 Rear wheel drive motor 45 Generator motor 100,200 vehicles

Claims

1. A motor control device provided in a vehicle equipped with a plurality of motors connected to a battery, a processor provided corresponding to each of the plurality of motors; Each of the processors acquires a torque instruction value, a rotation speed, and a power loss of the motor corresponding to the own processor, and derives a first power that is consumed by the motor or that is output from the motor to the battery when the motor operates to output a torque of the torque instruction value based on the torque instruction value, the rotation speed, and the power loss; acquiring a current value and a voltage value of the motor corresponding to the own processor, and deriving a second power consumed by the motor or output from the motor to the battery based on the current value and the voltage value; transmitting the second power to another of the processors; obtaining the second power derived by the processor from the other processor; deriving a third power by adding the derived second power and the second power acquired from the other processor; acquiring a fourth power output from or input to the battery; obtaining a power limit value for the battery; deriving a control power limit value by correcting the power limit value based on the third power and the fourth power; allocating the control power limit value to the motors corresponding to the own processor based on axle torque ratios of the plurality of motors; correcting a power value allocated to the motor corresponding to the own processor based on the first power and the second power derived by the own processor to derive an individual power limit value of the battery for the motor, and deriving a power correction amount for the first power when the first power exceeds the individual power limit value; A motor control device that corrects the torque command value of the motor corresponding to its own processor based on the power correction amount, and operates the motor according to the corrected torque command value.

2. 2. The motor control device according to claim 1, Each of the processors If the first power derived based on the torque command value exceeds the individual power limit value immediately before the torque command value is acquired, the first power is corrected to the individual power limit value; A motor control device that corrects the allocated power value based on a delayed version of the corrected first power and the second power derived by its own processor.

3. 3. The motor control device according to claim 2, Each of the processors deriving a difference value between a delayed version of the corrected first power and the second power derived by the processor itself; The motor control device corrects the allocated power value based on the difference value to derive a new individual power limit value.

4. 4. The motor control device according to claim 3, Each of the processors derives the individual power limit value by subtracting the difference value from the allocated power value or by adding the difference value to the allocated power value.

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