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 Art

[0002] Patent Document 1 discloses a vehicle charge-discharge control device including a power storage device that stores electric power generated by a generator, an electric motor that functions as a drive source for a vehicle based on electric power from the generator or the power storage device and performs regenerative power generation during vehicle braking to charge the power storage device, and a controller that integrally controls these components. The controller includes chargeable power calculation means for calculating the chargeable power of the power storage device according to the state of the power storage device. During vehicle braking, the vehicle charge-discharge control device further includes regenerative power consumption means for consuming the power exceeding the calculated chargeable power of the regenerative power generated. The controller includes chargeable power correction value calculation means for calculating a chargeable power correction value obtained by correcting the chargeable power of the power storage device according to the control error between the chargeable power and the regenerative power consumption means, and chargeable power correction value switching means for switching the chargeable power correction value according to the control error of the regenerative power consumption means. The regenerative power consumption means consumes the power exceeding the chargeable power correction value among the regenerative power.

[0003] Patent Document 2 discloses an electric vehicle drive control device having an electromechanical machine, electromechanical machine rotation speed detection processing means for detecting the rotation speed of the electromechanical machine, efficiency calculation processing means for calculating the efficiency of the electromechanical machine, power limit value calculation processing means for calculating a power limit value corresponding to the battery state, torque limit value calculation processing means for calculating a torque limit value of the electromechanical machine torque based on the electromechanical machine rotation speed, efficiency, and power limit value, and electromechanical machine target torque calculation processing means for calculating an electromechanical machine target torque representing the target value of the electromechanical machine torque based on the torque limit value.

Prior Art Documents

Patent Documents

[0004] [Patent Document 1] Japanese Patent Publication No. 2004-328961 [Patent Document 2] Japanese Patent Publication No. 2003-259509 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] The technology disclosed herein aims to protect the battery installed in a vehicle while efficiently utilizing the battery's power. [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, comprising a processor provided corresponding to each of the plurality of motors, each of which acquires the torque instruction value, rotational speed, and power loss of the motor corresponding to its own processor, derives a first power consumed by the motor or output from the motor to the battery when the motor operates to output the torque of the torque instruction value based on the torque instruction value, acquires the current value and voltage value of the motor corresponding to its own processor, derives a second power consumed by the motor or output from the motor to the battery based on the current value and voltage value, transmits the second power to the other processor, acquires the second power derived by its processor from the other processor, and transmits the second power derived The process involves adding the power and the second power obtained from the other processor to derive a third power, obtaining a fourth power output from or input to the battery, obtaining the battery's power limit, correcting the power limit based on the third and fourth powers to derive a control power limit, distributing the control power limit to the motor corresponding to the processor based on the foot shaft torque ratio of the multiple motors, correcting the power value distributed to the motor corresponding to the processor based on the first power and the second power derived by the processor to derive an individual power limit for the battery for that motor, deriving a power correction amount for the first power if the first power exceeds the individual power limit, correcting the torque instruction value of the motor corresponding to the processor based on the power correction amount, and operating the motor according to the corrected torque instruction value. [Effects of the Invention]

[0007] The technology disclosed herein allows for the efficient use of battery power while protecting the battery installed in the vehicle. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing the general configuration of a vehicle equipped with a motor control device, which is one embodiment of the technology of this disclosure. [Figure 2] Figure 2 is a graph illustrating the control process of the motor ECU31 during discharge. [Figure 3] Figure 3 is a graph illustrating the control process of the motor ECU 31 during charging. [Figure 4] Figure 4 is a graph illustrating the method for deriving the error ΔP1. [Figure 5] Figure 5 is a graph illustrating the method for deriving the power loss ΔP2. [Figure 6] Figure 6 is a flowchart illustrating the operation of ICM1. [Figure 7] Figure 7 is a flowchart illustrating the operation of IPU2. [Figure 8] Figure 8 is a flowchart (part 1) illustrating the operation of the motor ECU 31. [Figure 9] Figure 9 is a flowchart (part 2) illustrating the operation of the motor ECU 31. [Figure 10] Figure 10 is a schematic diagram showing the general configuration of vehicle 200, which is a modified example of vehicle 100. [Figure 11] Figure 11 is a flowchart (part 1) illustrating the operation of the motor ECU 36 of vehicle 200. [Figure 12] Figure 12 is a flowchart (part 2) illustrating the operation of the motor ECU 36 of vehicle 200. [Figure 13] Figure 13 is a schematic diagram (part 1) showing the relationship between the power limit value on the discharge side and the power limit value for control. [Figure 14] Figure 14 is a schematic diagram (part 2) showing the relationship between the power limit value on the discharge side and the power limit value for control. [Figure 15] Figure 15 is a schematic diagram (part 1) showing the relationship between the charging power limit and the control power limit. [Figure 16]FIG. 16 is a schematic diagram (part 2) showing the relationship between the power limit value on the charging side and the control power limit value.

Embodiments for Carrying Out the Invention

[0009] FIG. 1 is a schematic diagram showing a schematic configuration of a vehicle equipped with a motor control device according to an aspect of the technology of the present disclosure. The vehicle 100 shown in FIG. 1 is an automobile having a pair of front wheels and a pair of rear wheels. The technology of the present disclosure is applicable not only to four-wheel vehicles but also to three-wheel vehicles, two-wheel vehicles, etc.

[0010] The vehicle 100 includes an ICM (intelligent control module) 1 including a processor (not shown), a battery 20, an IPU (intelligent power unit) 2 including 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 power generation motor 45 connected to an internal combustion engine (not shown). It is also possible to provide two front-wheel drive motors 43 and two rear-wheel drive motors 44 respectively as four motors.

[0011] The dashed arrows shown in FIG. 1 indicate communication paths. The thick solid lines shown in FIG. 1 indicate power paths. Hereinafter, each of the front-wheel drive motor 43, the rear-wheel drive motor 44, and the power generation motor 45 may also 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 by power supply from the battery 20 and generate power for the vehicle 100 to travel. The torque generated by the front-wheel drive motor 43 and the rear-wheel drive motor 44 is transmitted to the front wheels and the 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 during braking of the vehicle 100.

[0013] The electric power generated by the power generation motor 45 is used to drive the front-wheel drive motor 43 and the rear-wheel drive motor 44, or to charge the battery 20. The front-wheel drive motor 43, the rear-wheel drive motor 44, and the power generation motor 45 are each composed of, 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 power storage cells connected in series and supplies a high voltage of, for example, 100 to 200V. The power storage cell is, for example, a lithium-ion battery, a nickel-hydrogen battery, or an all-solid-state battery.

[0015] The IPU2 is provided with sensors for detecting the voltage, current, and temperature of the battery 20. Based on the information of these sensors, the processor of the IPU2 can derive the electric power (hereinafter referred to as BAT power PB) output from or input to the battery 20.

[0016] Also, the processor of the IPU2 determines the state of the battery 20 (such as SOC (State Of Charge)) based on the information of these sensors, reads out the information of the power limit value determined according to the state from the memory, and transmits it to the motor ECU31.

[0017] The power limit value of the battery 20 includes a discharge-side power limit value that is the output upper limit when the battery 20 outputs power (during discharge) and a charge-side power limit value that is the input upper limit when the battery 20 inputs power (during charging). The relationship between the state of the battery 20 and the power limit value is obtained experimentally or stored in a memory according to the usage conditions and specifications of the vehicle and the battery.

[0018] The PCU3 includes 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 PDU 33, PDU 34, and PDU 35, and a motor ECU (Electronic Control Unit) 31 that controls these in an overall manner.

[0019] The motor ECU31 includes a processor such as a CPU (Central Processing Unit) and memory. The motor ECU31 may contain a single processor or multiple processors. A processor is hardware that performs various processes by executing a program, and its specific configuration is an electrical circuit.

[0020] When the front-wheel drive motor 43 and rear-wheel drive motor 44 are operating as electric motors, the VCU32 boosts the DC voltage from the battery 20 and supplies it to the PDU33 and PDU34. When the front-wheel drive motor 43 and rear-wheel drive motor 44 are operating as generators, the VCU32 steps down the DC voltage supplied from the PDU33 and PDU34 and inputs it to the battery 20. When the generator motor 45 is generating power, the VCU32 steps down the DC voltage supplied from the PDU35 and inputs it to the battery 20. The VCU32 performs step-up and step-down voltage adjustment by controlling its built-in switching elements. Therefore, power loss due to switching may occur in the VCU32.

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

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

[0023] When the generator motor 45 is generating power, PDU35 converts the alternating current (AC) generated by the generator motor 45 into direct current (DC). PDU33, PDU34, and PDU35 each perform the AC-DC conversion by controlling a switching element. Therefore, power loss due to switching may occur in each of PDU33, PDU34, and PDU35.

[0024] PDU33, PDU34, and PDU35 each perform vector control. Based on the d-axis voltage command value Vd and q-axis voltage command value Vq input from the motor ECU31, they generate the d-axis current command value Id and the q-axis current command value Iq, and supply a three-phase AC current based on these values ​​to the motor coils.

[0025] The front-wheel drive motor 43, the rear-wheel drive motor 44, and the generator motor 45 are each equipped with a rotational speed sensor to detect their rotational speed. The rotational speed information of each motor is transmitted to the motor ECU 31.

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

[0027] Motor power refers to the power consumed by a motor when it is operating, or the power output from that motor to the battery 20. In the following, 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 as motor power P44, and the motor power of the generator motor 45 as motor power P45. Motor power P45 is the power output from the generator motor 45 to the battery 20.

[0028] Motor power can be derived by multiplying the d-axis current value Id and q-axis current value Iq, obtained by dq-converting the three-phase AC current detected by a current sensor installed on the motor, by the motor's d-axis voltage command value Vd and q-axis voltage command value Vq (Id × Vd + Iq × Vq).

[0029] Motor power P43 and motor power P44 should have a positive sign if they represent power consumed by the motor. Motor power P43 and motor power P44 should have a negative sign if they represent power output from the motor to the battery 20 (i.e., power being generated). Motor power P45 is power output from the motor to the battery 20, so it should have a negative sign.

[0030] For example, consider a case where 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 power. In this case, the power output from the battery 20 will be the value obtained by the calculation {P43 + P44 + (-P45)} plus the power loss ΔP2 in the power path from the battery 20 to each motor (switching loss in each PDU, switching loss in the VCU 32, and loss in the auxiliary equipment 4, etc.).

[0031] Furthermore, we consider the case where the front-wheel drive motor 43 and the rear-wheel drive motor 44 are operating as generators, and the generator motor 45 is generating power. In this case, the value obtained by subtracting the power loss ΔP2 from the absolute value of the calculation {(-P43)+(-P44)+(-P45)} will be input to the battery 20.

[0032] The processor in the motor ECU31 controls motor power P43, motor power P44, and motor power P45 to ensure that the BAT power PB does not exceed the above power limit. However, since the BAT power PB information is sent from the IPU2 to the motor ECU31 via a communication line, a delay occurs. In other words, the processor in the motor ECU31 cannot monitor the BAT power PB in real time.

[0033] Therefore, in this configuration, when the processor of the motor ECU 31 obtains the torque command value for each motor from the ICM1, it obtains the rotational speed of each motor from the rotational speed sensor and obtains the motor power loss (motor loss), which is determined by the state of each motor, from memory. The motor loss is determined experimentally and stored in advance in the memory of the motor ECU 31.

[0034] The processor of the motor ECU 31 derives the estimated power consumed by each motor or output from each motor to the battery 20 when each motor operates to output the torque of the specified torque value, based on the torque instruction value, rotational speed, and motor losses acquired for each motor.

[0035] in particular, (torque instruction value + motor internal correction torque) × rotational speed + motor losses The expected power of each motor is derived through this calculation. The correction torque within the motor is a value experimentally determined for each motor, or a value corrected in real time by feedback from the motor's rotational speed. Motor loss is a positive value when the motor is consuming power, and a negative value when the motor is generating power.

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

[0037] If the estimated power Pf and estimated power Pr are power consumed by the motor, they should be positive values. If the estimated power Pf and estimated power Pr are power output from the motor to the battery 20, they should be negative values, except when the motor is de-energized. Since the estimated power Pg is power output from the motor to the battery 20, it should be negative, except when the motor is de-energized.

[0038] The total estimated power PE can be calculated using the formula (Pf + Pr + (-Pg)) when the front-wheel drive motor 43 and rear-wheel drive motor 44 are operating as electric motors. When the front-wheel drive motor 43 and rear-wheel drive motor 44 are operating as generators, the total estimated power PE can be calculated as the absolute value of the value obtained using the formula ((-Pf) + (-Pr) + (-Pg)).

[0039] Figure 2 is a graph illustrating the control of the motor ECU 31 during discharge. For simplification, Figure 2 assumes that the torque values ​​of the rear-wheel drive motor 44 and the generator motor 45 are 0. As mentioned above, the BAT power PB cannot be monitored in real time. Therefore, the processor of the motor ECU 31 uses the total estimated 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 ECU31 derives a control power limit value that is basically smaller than the discharge-side power limit value (the discharge-side power limit value minus the discharge correction amount described later), although this may vary depending on the error. If the total estimated power PE derived when the torque instruction value is obtained from the ICM1 ​​exceeds this control power limit value, the processor of the motor ECU31 corrects the total estimated power PE to the control power limit value (see the downward arrow in the upper part of Figure 2).

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

[0042] Assuming there are no errors in the motor losses of each motor, if each motor is driven to generate the torque of the converted torque instruction value shown in Figure 2, the power consumed from the battery 20 will be the corrected total estimated power PE plus the power loss ΔP2 that occurs in the power path from the battery 20 to each motor.

[0043] However, in reality, motor losses can contain errors. For the motor loss error ΔP1 across all three motors, a positive value indicates an increase in loss, and a negative value indicates a decrease in loss.

[0044] When the error ΔP1 is a positive value, the power output from the battery 20 becomes the control power limit value plus the error ΔP1 and the power loss ΔP2. Therefore, by setting the discharge correction amount to be 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 power limit value.

[0045] This allows the upper limit of the BAT power PB to be brought as close as possible to the discharge-side power limit, while preventing the BAT power PB from exceeding the discharge-side power limit. As a result, the battery 20 is protected and its power is used efficiently.

[0046] If the error ΔP1 is a negative value, the power loss ΔP2 is added to the control power limit, and the absolute value of the error ΔP1 is subtracted to obtain the upper limit of power output from the battery 20. In this case as well, 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 power limit.

[0047] This allows the upper limit of the BAT power PB to be brought as close as possible to the discharge-side power limit, while preventing the BAT power PB from exceeding the discharge-side power limit. As a result, the battery 20 is protected and its power is used efficiently.

[0048] Figure 3 is a graph illustrating the control of the motor ECU 31 during charging, which is the negative side when the discharge in Figure 2 is considered the positive side. During charging (during the regenerative operation of the front-wheel drive motor 43 and the rear-wheel drive motor 44), the processor of the motor ECU 31 derives a control power limit value that is greater than the charging-side power limit value (the charging-side power limit value plus a charging correction amount).

[0049] The processor in the motor ECU 31 corrects the total estimated power PE, which is derived when the torque instruction value is obtained from the ICM1, to the control power limit value if it exceeds this control power limit value (see the downward arrow in Figure 3). The processor in the motor ECU 31 then converts the corrected total estimated power PE into a torque instruction value, taking into account the motor losses of each motor.

[0050] If the error ΔP1 is a positive value, the power input to the battery 20 is the upper limit obtained by subtracting the error ΔP1 from the control power limit and then subtracting the power loss ΔP2. Therefore, by making the difference between the control power limit and the charging power limit in Figure 3 (charging correction amount) 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 charging power limit.

[0051] This allows the upper limit of the BAT power PB to be brought as close as possible to the charging power limit while preventing the BAT power PB from exceeding the charging power limit. As a result, the battery 20 is protected and its charging is efficient.

[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 subtracted to obtain 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 power limit value.

[0053] This allows the upper limit of the BAT power PB to be brought as close as possible to the charging power limit while preventing the BAT power PB from exceeding the charging power limit. As a result, the battery 20 is protected and its charging is efficient.

[0054] Thus, the control power limit is derived by correcting the power limit based on the motor loss error ΔP1 and power loss ΔP2 across all three motors. Since the error ΔP1 and power loss ΔP2 can vary considerably depending on the circumstances, 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 power of each motor, and the total estimated 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 estimated power PE, and the BAT power PB to derive a control power limit value.

[0057] Figure 4 is a graph illustrating the derivation method of the error ΔP1. Figure 4 shows an example of the time variation of the total estimated 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 instruction value immediately before the timing at which the total estimated power PE was derived. Therefore, there is a time difference between the total estimated power PE and the total motor power PM.

[0058] The processor in the motor ECU31 derives the error ΔP1 by eliminating the time lag between the total estimated power PE and the total motor power PM, and then calculating the difference between the total estimated power PE and the total motor power PM.

[0059] First, the motor ECU31 processor corrects the calculated total estimated power PE to the control power limit value if the calculated total estimated power PE exceeds the control power limit value calculated when the previous torque instruction value was received. In the example in Figure 4, the portion PX shown by the dashed line in the figure is corrected to the control power limit value.

[0060] Next, the motor ECU31 processor delays the corrected total estimated power PE using a ring buffer and a low-pass filter (see the white arrow in the diagram).

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

[0062] Figure 5 is a graph illustrating the derivation method for power loss ΔP2. Figure 5 shows an example of the time evolution of the total motor power PM and the battery power PB. The battery power PB reaches the motor ECU 31 with a delay from the timing at which the total motor power PM is derived. Therefore, there is a time difference between the battery power PB and the total motor power PM.

[0063] The processor in the motor ECU31 derives the power loss ΔP2 by eliminating the time lag between the battery power PB and the total motor power PM, and then calculating the difference between the battery power PB and the total motor power PM.

[0064] First, the processor in 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 diagram). The processor in 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 be derived in the same way during charging.

[0065] Figure 6 is a flowchart illustrating the operation of the ICM1 ​​processor.

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

[0067] Next, the ICM1 ​​processor derives the distribution of driving force between the front and rear wheels (step S13). Then, the ICM1 ​​processor 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 ICM1 ​​processor derives the final torque instruction for each motor (step S15) and transmits the torque instruction values ​​for each motor to the motor ECU31 (step S16).

[0069] Figure 7 is a flowchart illustrating the operation of the IPU2 processor.

[0070] The IPU2 processor obtains the current, voltage, and temperature of the battery 20 from the sensors included in the IPU2 (step S21). Next, the IPU2 processor derives the battery state of the battery 20, such as the state of clock (SOC), resistance, and heat generation (step S22).

[0071] Next, the IPU2 processor obtains the power limit value for battery 20 corresponding to that battery state from a map stored in memory, based on the derived battery state (step S23).

[0072] Next, the IPU2 processor derives BAT power PB, which is the power output from or input to the battery 20, based on the current and voltage obtained in step S21 (step S24).

[0073] Next, the IPU2 processor sends the power limit value obtained in step S23 and the BAT power PB derived in step S24 to the motor ECU31 (step S25).

[0074] Figures 8 and 9 are flowcharts illustrating the operation of the motor ECU 31. The processor of the motor ECU 31 receives torque command values ​​for each motor from the ICM1 ​​(step S31) and power limit values ​​and BAT power PB from the IPU2 (step S32). The processor of the motor ECU 31 also acquires the rotational speed of each motor from the rotational speed sensor installed on each motor (step S33).

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

[0076] Furthermore, the processor of the motor ECU 31 retrieves the motor loss, which is determined by the combination of the torque instruction value received in step S31 and the rotational speed acquired in step S33, from the memory, and derives the estimated power for each motor based on the motor loss, torque instruction value, and rotational speed (step S35).

[0077] After step S35, the processor of the motor ECU 31 derives the total estimated power PE by summing the estimated power of each motor (step S36). Based on the BAT power PB received in step S32, the total motor power PM derived in step S34, and the total estimated power PE derived in step S36, the processor of the motor ECU 31 derives the correction amount (discharge correction amount or charge correction amount) for the power limit value received in step S32 using the method described above (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 a power correction amount for the total estimated power PE (the difference between the total estimated power PE and the control power limit when the total estimated power PE exceeds the control power limit) from the control power limit value derived in step S38 and the total estimated power PE derived in step S36 (step S39).

[0080] If the total estimated 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 estimated power Pg of the generator motor 45 by the amount of power correction derived in step S39 (step S40). In other words, by reducing the power that is to be generated by the generator motor 45, the total estimated power PE is controlled so as not to exceed the control power limit value.

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

[0082] Then, if the average rotational speed of the front wheels is greater than or equal to a threshold (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 power correction derived in step S39 (step S46). In other words, by reducing the power that is expected to be consumed by the front wheel drive motor 43, the system controls the system so that the total expected power PE does not exceed the control power limit value. The judgment in step S45 is YES when, for example, only the front wheels are slipping out of the two rear wheels.

[0083] If the average rotational speed of the front wheels is not greater than a threshold (step S45: NO), the processor of the motor ECU 31 determines whether the average rotational speed of the rear wheels is greater than a threshold (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 power correction derived in step S39 (step S48). In other words, by reducing the power that is expected to be consumed by the rear-wheel drive motor 44, the system controls the system so that the total expected power PE does not exceed the control power limit value. The determination in step S47 is YES when, for example, 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 at the power ratio of 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 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 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 losses of that motor (step S42).

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

[0088] Subsequently, the processor of the motor ECU 31 controls each motor to drive according to the corrected torque instruction value in step S43 (step S44).

[0089] The execution order of steps S31-S36 in Figures 8 and 9 can be arbitrary as long as it is consistent. For example, step S35 may be performed after steps S31 and S33, and may be performed in parallel with or before step S32 or step S34. Also, steps S31 to S34 may be performed in parallel, or their order may be arbitrarily changed.

[0090] With the vehicle 100 configured as described above, it is possible to protect the battery 20 by preventing over-discharge and over-charging, while also consuming the power of the battery 20 without waste and efficiently charging the battery 20.

[0091] Although the vehicle 100 is provided to have three motors, the technology of this disclosure is also applicable to configurations in which one of the three motors is removed, or in which one of the front-wheel drive motor 43 and the rear-wheel drive motor 44 and the generator motor 45 are removed.

[0092] Figure 10 is a schematic diagram showing the general configuration of vehicle 200, which is a modified version of vehicle 100. In vehicle 200, the VCU32, PDU35, and generator motor 45 are removed from vehicle 100, and the PCU3 is divided into PCU3A and PCU3B. The dashed arrows in Figure 10 indicate the communication paths. The thick solid lines in Figure 10 indicate the power paths.

[0093] PCU3A comprises a PDU33 and a motor ECU36 that controls the PDU33. PCU3B comprises a PDU34 and a motor ECU37 that controls the PDU34. Motor ECU36 and motor ECU37 are configured to communicate with ICM1 ​​and IPU2, respectively. Motor ECU36 and motor ECU37 are configured to communicate with each other.

[0094] Note that PCU3A and PCU3B do not need to be physically separated, but even in that case, motor ECU36 and motor ECU37 are provided separately.

[0095] Figures 11 and 12 are flowcharts illustrating the operation of the motor ECU 36 of vehicle 200. The operation of the motor ECU 37 of vehicle 200 is the same as that of the motor ECU 36, so its explanation is 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 "self-motor." For the operation of the motor ECU 37, simply replace "self-motor" with "rear-wheel drive motor 44" in the following explanation.

[0097] The processor of the motor ECU36 receives the torque command value for its own motor from the ICM1 ​​(step S51) and the power limit value and BAT power PB from the IPU2 (step S52). The processor of the motor ECU36 also obtains the rotational speed of its own motor from the rotational speed sensor installed on the motor (step S53).

[0098] Furthermore, the processor of the motor ECU 36 acquires a three-phase AC current value from a current sensor installed on its own motor. Based on the d-axis voltage command value and q-axis voltage command value of its own motor and the acquired three-phase AC current value of its own motor, the processor of the motor ECU 36 derives the motor power of its own motor (the same as the motor power P43 described above) and transmits the derived motor power to another motor ECU (motor ECU 37) (step S54). The processor of the motor ECU 37 then transmits the motor power of the rear-wheel drive motor 44, which is derived by a similar process, to the motor ECU 36.

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

[0100] The processor of the motor ECU 36 retrieves the motor loss of its own motor from memory, which is determined by the combination of the torque instruction value received in step S51 and the rotational speed acquired in step S53. Based on the acquired motor loss, torque instruction value, and rotational speed, it derives the estimated power of its own motor (the same as the estimated power Pf mentioned above) (step S56).

[0101] Next, the processor of the motor ECU 36 adds 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 for deriving the total motor power PM is as described above. Then, based on the derived total motor power PM and the BAT power PB received in step S52, the processor of the motor ECU 36 derives the correction amount for the power limit value received in step S52 (discharge correction amount or charge correction amount) (step S57).

[0102] In step S57, the processor of the motor ECU 36 delays the total motor power PM, as explained in Figure 5, and derives the difference between the delayed total motor power PM' and the BAT power PB as the correction amount for the power limit. This difference is the power loss that occurs in the power path from the battery 20 to each motor, and is denoted as the 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 power limit on the discharge side and the power limit on the control side. Figures 15 and 16 are schematic diagrams showing the relationship between the power limit on the charge side and the power limit on the control side.

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

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

[0107] Next, the processor of the motor ECU 36 distributes the control power limit value derived in step S58 to each motor based on the shaft torque ratio of the front-wheel drive motor 43 and the rear-wheel drive motor 44, and derives the distributed power value for its own motor (see Figures 13 and 14) (step S59). For example, if the shaft torque ratio of the front-wheel drive motor 43 and the rear-wheel drive motor 44 is 2:1, then 2 / 3 of the control power limit value is derived as the distributed power value for its own motor.

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

[0109] In step S60, the motor ECU36 processor, as explained in Figure 4, corrects the expected power Pf of its own motor to the individual power limit value of the motor immediately before (details will be described later), then delays the corrected expected power Pf, and derives the difference between the delayed expected power Pf' and the motor power P43 of its own motor as the motor loss error ΔP4 of its own 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 distributed 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 (meaning the motor's losses are greater than expected), as shown in Figure 13, the value obtained by subtracting the error ΔP4 (positive value) from the distributed power value of the front-wheel drive motor 43 is derived as the individual power limit value 43A for the front-wheel drive motor 43.

[0112] If the error ΔP4 is a negative value (meaning the motor's losses are less than expected), as shown in Figure 14, the value obtained by subtracting the error ΔP4 (negative value) from the distributed 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 distributed power value of the front-wheel drive motor 43, is derived as the individual power limit value 43A for the front-wheel drive motor 43 (see Figure 14).

[0113] The processor in the motor ECU 37 also performs the processing from steps S51 to S61. In Figures 13 and 14, the error derived by the processor in step S60 is denoted as error ΔP5.

[0114] The error ΔP5 is derived as the difference between the expected power Pr' of the rear-wheel drive motor 44 after delaying the expected power Pr, and the motor power P44 of the rear-wheel drive motor 44. For the error ΔP5, a positive value indicates an increase in loss, and a negative value indicates a decrease in loss.

[0115] If the error ΔP5 is a positive value, as shown in Figure 13, the value obtained by subtracting the error ΔP5 (positive value) from the distributed 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 distributed 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 distributed 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 estimated power of the motor (the difference between the estimated power and the individual power limit when the estimated power exceeds the individual power limit) from the individual power limit value derived in step S61 and the estimated 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 its own motor by the amount of power correction derived in step S62 (step S63). In other words, it controls the motor so that its expected power does not exceed the individual power limit.

[0119] Next, the processor of the motor ECU36 converts the corrected estimated power of its own motor into torque, taking into account the motor losses of its own motor (step S64).

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

[0121] Subsequently, the processor of the motor ECU36 performs control to drive its own motor according to the corrected torque instruction value in step S65 (step S66).

[0122] In the example shown in Figure 13, the power consumption of the front-wheel drive motor 43, which operates as an electric motor according to the corrected torque instruction value, is capped at the value obtained by adding the error ΔP4 to the individual power limit value 43A (= the distributed 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 according to the corrected torque instruction value, is capped at the value obtained by adding the error ΔP5 to the individual power limit value 44A (= the distributed power value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and rear-wheel drive motor 44 operate according to the corrected torque instruction value, a power loss ΔP3 occurs.

[0123] Therefore, when the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate according to the corrected torque instruction value, the power consumed from the battery 20 is the sum of the power distribution value of the front-wheel drive motor 43, the power distribution value of the rear-wheel drive motor 44, and the power loss ΔP3. This sum matches the power limit value on the discharge side.

[0124] Therefore, by correcting the torque instruction 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 instruction 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 Figure 14, the power consumption of the front-wheel drive motor 43, which operates as an electric motor according to the corrected torque instruction value, is capped at the value obtained by subtracting the error ΔP4 from the individual power limit value 43A (= the distributed 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 according to the corrected torque instruction value, is capped at the value obtained by subtracting the error ΔP5 from the individual power limit value 44A (= the distributed power value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and rear-wheel drive motor 44 operate according to the corrected torque instruction value, a power loss ΔP3 occurs. Therefore, as in the case of Figure 13, the power output from the battery 20 can be kept below the power limit value on the discharge side.

[0126] In the example shown in Figure 15, the power generated by the front-wheel drive motor 43, which operates as a generator according to the corrected torque instruction value, is capped at the value obtained by subtracting the error ΔP4 from the individual power limit value 43A (= the distributed power value of the front-wheel drive motor 43). Similarly, the power generated by the rear-wheel drive motor 44, which operates as a generator according to the corrected torque instruction value, is capped at the value obtained by subtracting the error ΔP5 from the individual power limit value 44A (= the distributed power value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and rear-wheel drive motor 44 operate according to the corrected torque instruction value, a power loss ΔP3 occurs.

[0127] Therefore, when the front-wheel drive motor 43 and the rear-wheel drive motor 44 operate according to the corrected torque instruction value, the power input to the battery 20 is the sum of the power distribution value of the front-wheel drive motor and the power distribution value of the rear-wheel drive motor minus the power loss ΔP3, and this value matches the power limit value on the charging side.

[0128] Therefore, by correcting the torque instruction 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 instruction 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 Figure 16, the power generated by the front-wheel drive motor 43, which operates as a generator according to the corrected torque instruction value, is capped at the value obtained by adding the error ΔP4 to the individual power limit value 43A (= the distributed power value of the front-wheel drive motor 43). Similarly, the power generated by the rear-wheel drive motor 44, which operates as a generator according to the corrected torque instruction value, is capped at the value obtained by adding the error ΔP5 to the individual power limit value 44A (= the distributed power value of the rear-wheel drive motor 44). When the front-wheel drive motor 43 and rear-wheel drive motor 44 operate according to the corrected torque instruction value, a power loss ΔP3 occurs. Therefore, as in the case of Figure 15, the power input to the battery 20 can be kept below the power limit value on the charging side.

[0130] As described above, in the vehicle 200, each motor ECU (motor ECU 36, motor ECU 37) provided for each motor can derive its own individual power limit value for the motor it corresponds to. In this way, an individual power limit value and estimated power can be derived for each motor, and the torque instruction value can be corrected based on that individual power limit value and estimated power. Therefore, compared to a configuration in which, for example, motor ECU 36 and motor ECU 37 are replaced by a single ECU, torque correction for each motor can be performed at high speed.

[0131] This specification contains at least the following information. Note that the components etc. in parentheses indicate those corresponding to the embodiments described above, but are not limited thereto.

[0132] (1) A motor control device (a concept including PCU3A and PCU3B) provided in a vehicle (vehicle 100) equipped with multiple motors (front-wheel drive motor 43, rear-wheel drive motor 44) connected to a battery, Each of the above-mentioned motors is equipped with a corresponding processor (motor ECU36, motor ECU37), Each of the above processors is: The system obtains the torque instruction value, rotational speed, and power loss of the motor corresponding to the processor, and derives the first power (estimated power Pf or estimated power Pr) that is consumed by the motor or output from the motor to the battery when the motor operates to output the torque of the torque instruction value, based on the torque instruction value, rotational speed, and power loss. The current and voltage values ​​of the motor corresponding to the processor are obtained, and based on the current and voltage values, the second power (motor power P43 or motor power P44) consumed by the motor or output from the motor to the battery is derived. The above second power is transmitted to the other above processors, The second power derived from the other processor is obtained from that processor. The second power derived above and the second power obtained from the other processors are added together to derive the third power (total motor power PM). The fourth power (BAT power PB) output from or input to the above battery is obtained. Obtain the power limit value of the above battery, Based on the above third power and fourth power, the above power limit value is corrected to derive the control power limit value. The above control power limit is distributed to the motor corresponding to the processor based on the foot shaft torque ratio of the multiple motors. The power value (distributed power value) allocated to the motor corresponding to the self-processor is corrected based on the first power and the second power derived by the self-processor to derive an individual power limit value for the battery for that motor, and if the first power exceeds the individual power limit value, a power correction amount for the first power is derived. A motor control device that corrects the torque instruction value of the motor corresponding to its own processor based on the above power correction amount, and operates the motor according to the corrected torque instruction value.

[0133] (2) (1) The motor control device described above, Each of the above processors is: If the first power derived based on the torque instruction value exceeds the individual power limit value immediately before acquiring the torque instruction value, the first power is corrected to the individual power limit value. A motor control device that corrects the allocated power value based on the first power after correction (estimated power Pf' or estimated power Pr') with a delay, and the second power (motor power P43 or motor power P44) derived by its own processor.

[0134] (3) (2) The motor control device described above, Each of the above processors is: The difference between the corrected first power (after delay) and the second power (error ΔP4 or error ΔP5) derived by the processor is calculated. A motor control device that corrects the allocated power values ​​based on the difference values ​​to derive new individual power limit values.

[0135] (4) (3) The motor control device described above, Each of the above processors is a motor control device that derives the above individual power limit value by subtracting the above difference value from the above allocated power value, or by adding the above difference value to the above allocated power value. [Explanation of Symbols]

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

Claims

1. A motor control device installed in a vehicle equipped with multiple motors connected to a battery, Each of the aforementioned multiple motors is equipped with a processor corresponding to it. Each of the aforementioned processors is The system obtains the torque instruction value, rotational speed, and power loss of the motor corresponding to the processor, and derives a first power that is consumed by the motor or output from the motor to the battery when the motor operates to output the torque of the torque instruction value, based on the torque instruction value, rotational speed, and power loss. The current and voltage values ​​of the motor corresponding to the processor are obtained, and based on the current and voltage values, the second power consumed by the motor or output from the motor to the battery is derived. The second power is transmitted to the other processor, The second power derived from the other processor is obtained from the said processor, The derived second power and the second power obtained from the other processor are added together to derive the third power. The fourth power output from or input to the aforementioned battery is acquired. The power limit value of the aforementioned battery is obtained, Based on the third power and the fourth power, the power limit value is corrected to derive a control power limit value. The control power limit is distributed to the motor corresponding to the processor based on the foot shaft torque ratio of the plurality of motors. The power value allocated to the motor corresponding to the self-processor is corrected based on the first power and the second power derived by the self-processor to derive an individual power limit value for the battery for the motor, and if the first power exceeds the individual power limit value, a power correction amount for the first power is derived. A motor control device that corrects the torque instruction value of the motor corresponding to its own processor based on the power correction amount, and operates the motor according to the corrected torque instruction value.

2. A motor control device according to claim 1, Each of the aforementioned processors is If the first power derived based on the torque instruction value exceeds the individual power limit value immediately before acquiring the torque instruction value, the first power is corrected to the individual power limit value. A motor control device that corrects the allocated power value based on the first power after correction and the second power derived by its own processor, with the first power delayed.

3. A motor control device according to claim 2, Each of the aforementioned processors is The difference between the first power after correction and the second power derived by the processor is calculated. A motor control device that corrects the allocated power values ​​based on the difference value to derive new individual power limit values.

4. A motor control device according to claim 3, Each of the processors is a motor control device that 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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