Electric vehicle control system

Abstract

To provide an electric vehicle control system capable of correcting motor efficiency set as a design value to bring the motor efficiency closer to an actual value. [Solution] The system comprises a motor 2, a battery 4 that supplies power to the motor 2, and a control unit 5 that controls the motor 2 based on a predetermined motor efficiency, which is the ratio of the output of the motor 2 to the power input to the motor 2. If the deviation between the actual motor output, which is the actual output of the motor 2, and the estimated motor output obtained by multiplying the actual power, which is the actual power input to the motor 2 from the battery 4, by the motor efficiency is outside a predetermined range, the control unit 5 corrects the motor efficiency so that it falls within the range.

Description

[Technical Field]

[0001] The present invention relates to an electric vehicle control system. [Background technology]

[0002] Conventionally, motors in electric vehicles are controlled using motor efficiency, which is the ratio of motor output to electric power.

[0003] Patent Document 1 describes a method of calculating the power generation drive efficiency, which is the total efficiency of the generator and motor, by multiplying the generator efficiency and the motor efficiency, calculating the power generation drive conversion coefficient between the generator and the motor by multiplying the power generation drive speed ratio, which is the ratio of the rotational speeds of the generator and the motor, multiplying the power generation drive conversion coefficient by the power generation torque command value to calculate a motor drive torque estimate, and calculating the power generation torque command value based on the motor drive torque estimate that has been filtered. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6326755 Summary of the Invention [Problem to be solved by the invention]

[0005] Motor efficiency is determined in advance as a design value through experiments, calculations, etc., but there is a possibility that the design value and the actual value may differ due to variations in the manufacturing of motor parts, etc. Because the battery power required to output a specified motor torque is calculated based on the motor efficiency, if the degree of deviation is large, there is a possibility that the allowable output may not be maintained or the performance may not be fully utilized.

[0006] Therefore, an object of the present invention is to provide an electric vehicle control system that can correct the motor efficiency set as a design value to bring the motor efficiency closer to the actual value. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention comprises a motor, a battery that supplies power to the motor, and a control unit that controls the motor based on a predetermined motor efficiency, which is the ratio of the motor's output to the power input to the motor, and if the deviation between the actual motor output, which is the actual output of the motor, and the estimated motor output obtained by multiplying the actual power, which is the actual power input to the motor from the battery, by the motor efficiency is outside a predetermined range, the control unit corrects the motor efficiency so that it falls within the range. [Effects of the Invention]

[0008] In this way, according to the present invention, the motor efficiency set as a design value can be corrected to bring the motor efficiency closer to the actual value. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic diagram of a vehicle equipped with an electric vehicle control system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a control block diagram showing the procedure of the motor efficiency correction process of the electric vehicle control system according to one embodiment of the present invention. [Figure 3] FIG. 3 is a control block diagram showing the procedure of the control execution determination process of the electric vehicle control system according to one embodiment of the present invention. [Figure 4] FIG. 4 is a time chart showing changes in the motor efficiency correction coefficient due to the motor efficiency correction process and the control execution determination process of the electric vehicle control system according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] An electric vehicle control system according to one embodiment of the present invention includes a motor, a battery that supplies power to the motor, and a control unit that controls the motor based on a predetermined motor efficiency, which is the ratio of the motor output to the power input to the motor. The control unit is configured to correct the motor efficiency, if the deviation between the actual motor output, which is the actual output of the motor, and the estimated motor output obtained by multiplying the actual power, which is the actual power input to the motor from the battery, by the motor efficiency, is outside a predetermined range, so that the deviation falls within the range.

[0011] As a result, the electric vehicle control system according to one embodiment of the present invention can correct the motor efficiency that is set as a design value, and bring the motor efficiency closer to the actual value. [Example]

[0012] Hereinafter, an electric vehicle control system according to an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] In FIG. 1, a vehicle 1 equipped with an electric vehicle control system according to an embodiment of the present invention includes a motor 2, an inverter 3, a battery 4, and a control unit 5.

[0014] The motor 2 is configured as a synchronous motor, for example, equipped with a rotor in which multiple permanent magnets are embedded and a stator around which a stator coil is wound. When three-phase AC power is applied to the stator coil, a rotating magnetic field is formed in the stator, which rotates the rotor and generates a driving force.

[0015] Furthermore, the motor 2 is driven so that the rotational resistance generated during power generation is used to brake the vehicle 1. This allows the motor 2 to generate power through regeneration. In this way, the motor 2 also functions as a generator, and is capable of generating power to charge the battery 4.

[0016] The rotating shaft of the motor 2 is connected to the drive shaft 11 via a reducer 21. The motor 2 drives the drive wheels 10 via the drive shaft 11.

[0017] The motor 2 is provided with a motor state sensor 91 that detects the rotation speed of the rotary shaft of the motor 2 and the torque output by the motor 2. The drive wheels 10 are provided with wheel speed sensors 96 that detect the rotation speed of the drive wheels 10.

[0018] The inverter 3 supplies three-phase AC power to the motor 2 under the control of the control unit 5. The inverter 3 also converts the three-phase AC power generated by the motor 2 into DC power and charges the battery 4.

[0019] The battery 4 is, for example, a nickel storage battery or a lithium storage battery, and is configured by connecting multiple cells in series. The battery 4 supplies power to the motor 2 via the inverter 3. The battery 4 is provided with a battery state sensor 92. The battery state sensor 92 detects the charge / discharge current, voltage, and battery temperature of the battery 4.

[0020] The control unit 5 is configured by a computer unit that includes a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), an input port, and an output port.

[0021] The ROM of the control unit 5 stores various control constants, various maps, and the like, as well as a program for causing the computer unit to function as the control unit 5. That is, the computer unit functions as the control unit 5 when the CPU executes the program stored in the ROM.

[0022] The input port of the control unit 5 is connected to various sensors including the motor state sensor 91, the battery state sensor 92, and the wheel speed sensor 96. On the other hand, the output port of the control unit 5 is connected to various control targets including the inverter 3.

[0023] In this embodiment, if the deviation between the actual motor output, which is the actual output of the motor 2, and the estimated motor output obtained by multiplying the actual power, which is the actual power input to the motor 2 from the battery 4, by the motor efficiency is outside a predetermined range, the control unit 5 corrects the motor efficiency so that it falls within the predetermined range.

[0024] If the deviation between the actual motor output and the estimated motor output is outside a predetermined range and the actual motor output is greater than the estimated motor output, the control unit 5 corrects the motor efficiency to increase it. If the deviation between the actual motor output and the estimated motor output is outside a predetermined range and the actual motor output is smaller than the estimated motor output, the control unit 5 corrects the motor efficiency to decrease it. The correction amount should be set taking into consideration that drivability will not deteriorate. The correction amount may be gradually changed up to the target correction amount. The smaller the correction amount, the smaller the fluctuation in the output of the motor 2 after correction. The predetermined range is the range within which the deviation of the motor efficiency from the actual state of the motor 2 is acceptable.

[0025] The actual motor output is calculated by multiplying the actual motor rotation speed, which is the actual rotation speed of the motor 2, by the actual motor torque, which is the actual output torque of the motor. The estimated motor output is calculated by multiplying the battery output, which is calculated by multiplying the actual current value of the battery 4 by the actual voltage value of the battery 4, by the motor efficiency.

[0026] The control unit 5 integrates the actual motor output and the estimated motor output at a predetermined cycle, and when either integrated value becomes larger than a predetermined integrated value, it performs motor efficiency correction control and then resets each integrated value to zero.

[0027] As a motor efficiency correction control, the control unit 5 compares the integrated value of the actual motor output with the integrated value of the estimated motor output, and if the difference between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range, corrects the motor efficiency so that it falls within the predetermined range.

[0028] If the difference between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range and the integrated value of the actual motor output is larger than the integrated value of the estimated motor output, the control unit 5 corrects the motor efficiency to be larger.If the difference between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range and the integrated value of the actual motor output is smaller than the integrated value of the estimated motor output, the control unit 5 corrects the motor efficiency to be smaller.

[0029] The control unit 5 corrects the motor efficiency, for example, by multiplying the design motor efficiency by a motor efficiency correction coefficient. The motor efficiency correction coefficient is initially set to 1, and the value is updated by correction. The corrected motor efficiency correction coefficient is stored and used in the next driving cycle.

[0030] The motor efficiency, the integrated value of the actual motor output, the integrated value of the estimated motor output, and the motor efficiency correction coefficient are calculated separately for when the motor 2 is powering and when it is regenerating.

[0031] The motor efficiency correction process performed by the electric vehicle control system according to this embodiment configured as described above will be described with reference to Fig. 2. The motor efficiency correction process described below starts when the control unit 5 starts operating, and is executed at preset time intervals.

[0032] In the multiplication unit 101, the control unit 5 multiplies the design value (Spec value) of the motor efficiency by the motor efficiency correction coefficient of the previous cycle to calculate and output the corrected motor efficiency.

[0033] The design value of the motor efficiency is found from a map that determines the motor efficiency from the motor torque and motor rotation speed when the motor 2 is powering and when it is regenerating.

[0034] The motor efficiency correction coefficient for the previous cycle is a correction coefficient obtained by the motor efficiency correction process for the previous cycle.

[0035] In the multiplication unit 102, the control unit 5 multiplies the battery output by the corrected motor efficiency to calculate and output the estimated motor output.

[0036] In the integrating section 103, the control section 5 outputs an integrated value calculated by adding the value of the actual motor output in the current cycle to the integrated value of the actual motor output up to the previous cycle.

[0037] In the integrating section 104, the control section 5 outputs an integrated value calculated by adding the value of the estimated motor output in the current cycle to the integrated value of the estimated motor output up to the previous cycle.

[0038] The integration in the integration unit 103 and the integration unit 104 is performed when the motor 2 is in power running and when it is in regeneration, respectively.

[0039] In the integrating units 103 and 104, when the control execution condition signal from the control execution determination process described later is "1" indicating "reset", the control unit 5 resets the integrated value of the actual motor output and the integrated value of the estimated motor output to zero.

[0040] In the division unit 105, the control unit 5 divides the integrated value of the actual motor output by the integrated value of the estimated motor output and outputs the result.

[0041] In processing unit 106, control unit 5 updates the motor efficiency correction coefficient to correct motor efficiency when the control execution condition signal from the control execution determination process described below is "1" indicating "reflected" and when the value output by division unit 105 is outside a predetermined range. The closer the value output by division unit 105 is to 1, the smaller the deviation between the design value and the actual value, and if the value deviates from 1 by more than a predetermined tolerance, it is determined to be outside the predetermined range.

[0042] When the control unit 5 determines that the value output by the division unit 105 is outside the predetermined range and the integrated value of the actual motor output is greater than the integrated value of the estimated motor output, the control unit 5 adds a value obtained by multiplying the motor efficiency correction coefficient of the previous cycle by the weighting coefficient to the motor efficiency correction coefficient of the previous cycle and outputs the result as a new motor efficiency correction coefficient.

[0043] When the control unit 5 determines that the value output by the division unit 105 is outside the predetermined range and the integrated value of the actual motor output is smaller than the integrated value of the estimated motor output, the control unit 5 subtracts the value obtained by multiplying the motor efficiency correction coefficient of the previous cycle by the weighting coefficient from the motor efficiency correction coefficient of the previous cycle and outputs the result as a new motor efficiency correction coefficient.

[0044] When correcting the motor efficiency correction coefficient, the motor efficiency correction coefficient is gradually changed by multiplying it by a weighting coefficient, thereby preventing deterioration of drivability.

[0045] In the multiplication unit 107, the control unit 5 multiplies the design value (Spec value) of the motor efficiency by the updated motor efficiency correction coefficient to calculate and output the corrected motor efficiency. The corrected motor efficiency output from the multiplication unit 107 is used as the motor efficiency.

[0046] In the delay unit 108, the control unit 5 delays the motor efficiency correction coefficient calculated this time until the processing of the next cycle, and then outputs the delayed coefficient.

[0047] The control execution determination process by the electric vehicle control system according to this embodiment will be described with reference to Fig. 3. The control execution determination process described below is started simultaneously with the motor efficiency correction process described above when the control unit 5 starts operation, and is executed at the same time intervals as the motor efficiency correction process described above. In Fig. 3, the control execution condition signal is output by determining whether the integrated value of the estimated motor output is greater than a predetermined integrated value, but the determination may also be made based on the integrated value of the actual motor output, or whether any integrated value is greater than a predetermined integrated value.

[0048] In the multiplication unit 111, the control unit 5 multiplies the design value (Spec value) of the motor efficiency by the motor efficiency correction coefficient of the previous cycle to calculate and output the corrected motor efficiency.

[0049] In the multiplication unit 112, the control unit 5 multiplies the battery output by the corrected motor efficiency to calculate and output the estimated motor output.

[0050] In the integrating section 113, the control section 5 outputs an integrated value calculated by adding the value of the estimated motor output in the current cycle to the integrated value of the estimated motor output up to the previous cycle.

[0051] In the judgment unit 114, the control unit 5 judges whether the integrated value of the estimated motor output output by the integrator 113 is greater than a predetermined integrated value, and if the integrated value of the estimated motor output output by the integrator 113 is greater than the predetermined integrated value, outputs "1" as the control implementation condition signal, and if the integrated value of the estimated motor output output by the integrator 113 is not greater than the predetermined integrated value, outputs "0" as the control implementation condition signal.

[0052] In the delay unit 115, the control unit 5 delays the control execution condition signal calculated this time until the processing of the next cycle and outputs it.

[0053] In the integrating unit 113, the control unit 5 resets the integrated value of the estimated motor output to zero when the control execution condition signal in the previous cycle from the delay unit 115 is "1" indicating "reset."

[0054] The integrated value is calculated when the motor 2 is powered and when it is regenerated, and is determined to be a predetermined integrated value.

[0055] The operations of the motor efficiency correction process and the control execution determination process will be described with reference to FIG.

[0056] The actual motor output and the estimated motor output are accumulated, and at time t1, when the accumulated value of the estimated motor output becomes larger than a predetermined accumulated value, it is determined whether the deviation between the accumulated value of the actual motor output and the accumulated value of the estimated motor output is outside a predetermined range, and since the accumulated value of the actual motor output is smaller than the accumulated value of the estimated motor output, the motor efficiency correction coefficient is changed to a smaller value, the accumulated value is reset, and accumulation begins again.

[0057] At time t2, when the integrated value of the estimated motor output becomes larger than a predetermined integrated value, it is determined whether the deviation between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range, and since the integrated value of the actual motor output is smaller than the integrated value of the estimated motor output, the motor efficiency correction coefficient is changed to a smaller value, the integrated value is reset, and accumulation begins again.

[0058] At time t3, when the integrated value of the estimated motor output becomes larger than a predetermined integrated value, it is determined whether the deviation between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range. Since the deviation between the integrated value of the actual motor output and the integrated value of the estimated motor output is not outside the predetermined range, the motor efficiency correction coefficient is not changed, the integrated value is reset, and accumulation begins again.

[0059] In this way, in this embodiment, if the deviation between the actual motor output, which is the actual output of the motor 2, and the estimated motor output obtained by multiplying the actual power, which is the actual power input to the motor 2 from the battery 4, by the motor efficiency is outside a predetermined range, the control unit 5 corrects the motor efficiency so that it falls within the range.

[0060] As a result, the estimated motor output calculated from the actual power and motor efficiency is compared with the actual motor output, and if the deviation is outside a specified range, it is corrected to fall within the specified range, thereby correcting the motor efficiency set as a design value and bringing the motor efficiency closer to the actual value.

[0061] In addition, the control unit 5 accumulates the actual motor output and the estimated motor output at a predetermined cycle, and when either accumulated value becomes larger than a predetermined accumulated value, it compares the accumulated value of the actual motor output with the accumulated value of the estimated motor output.If the difference between the accumulated value of the actual motor output and the accumulated value of the estimated motor output is outside a predetermined range, it corrects the motor efficiency so that it falls within the predetermined range, and then resets each accumulated value to zero.

[0062] As a result, the actual motor output and the estimated motor output are integrated and compared, so that fluctuations in motor efficiency due to sudden disturbances can be suppressed.

[0063] In addition, since the integrated value is reset when it becomes larger than a predetermined integrated value, after correcting the motor efficiency, the estimated motor output and actual motor output values ​​before correction can be excluded, and the deviation of the motor efficiency from the actual state of motor 2 can be determined using the corrected integrated value.

[0064] In this embodiment, an example has been described in which the control unit 5 performs various judgments and calculations based on various sensor information, but this is not limited to this. The vehicle 1 may be provided with a communication unit capable of communicating with an external device such as an external server, and various judgments and calculations may be performed by the external device based on the detection information of the various sensors transmitted from the communication unit. The judgment results and calculation results may be received by the communication unit, and various controls may be performed using the received judgment results and calculation results.

[0065] While an embodiment of the present invention has been disclosed, it will be apparent to one skilled in the art that modifications may be made thereto without departing from the scope of the present invention, and it is intended that all such modifications and equivalents be included in the following claims. [Explanation of symbols]

[0066] 1 vehicle 2 motors 3 inverters 4 Battery 5. Control section 91 Motor status sensor 92 Battery Status Sensor

Claims

1. a motor, a battery for supplying power to the motor; a control unit that controls the motor based on a preset motor efficiency, which is a ratio of an output of the motor to an electric power input to the motor; When a deviation between an actual motor output, which is the actual output of the motor, and an estimated motor output obtained by multiplying actual power, which is the actual power input to the motor from the battery, by the motor efficiency is outside a predetermined range, the control unit corrects the motor efficiency so that the deviation falls within the range.

2. 2. The electric vehicle control system according to claim 1, wherein the control unit integrates the actual motor output and the estimated motor output at a predetermined cycle, and when either integrated value becomes larger than a predetermined integrated value, compares the integrated value of the actual motor output with the integrated value of the estimated motor output, and when a difference between the integrated value of the actual motor output and the integrated value of the estimated motor output is outside a predetermined range, corrects the motor efficiency so that it falls within the predetermined range, and when a difference between the integrated value of the actual motor output and the integrated value of the estimated motor output is within a predetermined range, leaves the motor efficiency as it is and then resets each integrated value to zero.

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