JP6643062B2 - Electric car control device - Google Patents

Description

  The present invention relates to an electric vehicle control device that controls an electric motor that drives an electric vehicle.

  As an example of an electric vehicle control device that controls an electric motor that drives an electric vehicle (vehicle), Patent Document 1 discloses an electric vehicle control device that determines the rotational speed of the electric motor by calculation and controls the torque of the electric motor. According to such an electric vehicle control device, the electric motor can be controlled according to the torque command Tqr without using the speed sensor. By transmitting the torque of the electric motor to the wheel shaft of the vehicle, the vehicle can be accelerated or decelerated.

  FIG. 6 is a diagram illustrating a configuration example of an electric vehicle control device that controls the electric motor by calculating the rotational speed of the electric motor by calculation as described above.

  The electric vehicle control device 10 shown in FIG. 6 includes a power converter 11, a current detector 12, a speed calculator 13, a slip frequency command generator 14a, an adder 15, a current command generator 16a, a torque And a control unit 17a.

  The torque command Tqr and the magnetic flux command Ifr are input to the slip frequency command generator 14a and the current command generator 16a.

Power converter 11 is outputted from the torque control section 17a, amplifies instructs the voltage command V ^* to output voltages to the motor 1 applies a voltage v corresponding to the voltage command V ^* obtained by amplifying the motor 1.

  The current detector 12 detects a current i flowing through the electric motor 1 and outputs a detection result to the speed calculation unit 13 and the torque control unit 17a.

Based on the voltage command V ^* output from the torque controller 17a and the current i detected by the current detector 12, the speed calculator 13 calculates the speed of the electric motor 1 using the following equations (1) to (5). The rotation speed (calculation speed ωmc) is calculated.

Here, R1 and R2 are the primary resistance and the secondary resistance of the motor 1, respectively, and L1 and L2 are the primary self-inductance and the secondary self-inductance of the motor 1, respectively. FA and FB are the a-axis component and the b-axis component of the magnetic flux φ of the induction machine determined by Expression (1). Note that a voltage v applied to the electric motor 1 may be used instead of the voltage command V ^* .

  The speed calculation unit 13 outputs the calculated calculation speed ωmc to the adder 15.

  The slip frequency command generator 14a generates a slip frequency command ωsr using the following equation (6) based on the torque command Tqr and the magnetic flux command Ifr, and outputs the slip frequency command ωsr to the adder 15.

  The adder 15 adds the calculation speed ωmc output from the speed calculation unit 13 and the slip frequency command ωsr output from the slip frequency command generation unit 14a, and specifies a frequency command that indicates the frequency of the voltage applied to the electric motor 1. ωi is generated and output to the torque control unit 17a.

  Based on the torque command Tqr and the magnetic flux command Ifr, the current command generating unit 16a uses the following equations (7) and (8) to flow the magnetic flux of the motor 1 to the motor 1 to control the magnetic flux according to the magnetic flux command Ifr. A magnetic flux component current command Id for instructing a current and a torque component current command Iq for instructing a current flowing through the motor 1 for controlling the torque of the motor 1 in accordance with the torque command Tqr are generated and output to the torque control unit 17a.

The torque control unit 17a includes a magnetic flux component current command Id and a torque component current command Iq output from the current command generation unit 16a, a current i detected by the current detector 12, and a frequency command ωi output from the adder 15. , And generates a voltage command V ^*, and outputs it to the power converter 11 and the speed calculator 13.

JP-A-11-69895

  In the electric vehicle control device 10 shown in FIG. 6, when the primary resistance R1 fluctuates due to the temperature fluctuation of the electric motor 1, an error occurs in the induction motor magnetic flux φ obtained by using the equation (1). Errors also occur. In particular, when the vehicle is running at low speed, large errors are likely to occur in the induction machine magnetic flux φ and the calculation speed ωmc. If an error occurs in the calculation speed ωmc, it becomes impossible to control the torque of the electric motor 1 in accordance with the torque command Tqr. As a result, the vehicle cannot be accelerated or decelerated as expected, and the vehicle may move in a direction opposite to a desired traveling direction when the vehicle is traveling at a low speed (including when the vehicle is stopped).

When the motor 1 is rotating forward, the frequency command ωi is limited to a lower limit by a positive value, and when the motor 1 is rotating backward, a voltage command V ^* is generated using a limited frequency command ωiL in which the frequency command ωi is limited to an upper limit by a negative value. Is also conceivable. By generating the voltage command V ^* using the limited frequency command ωiL, even if an error occurs in the calculation speed ωmc, the voltage command V ^* that causes the motor 1 to output a torque in a direction opposite to the rotation direction command of the motor 1 is generated. Since it is not performed, it is possible to suppress the vehicle from moving in the opposite direction to the desired traveling direction.

  However, when the frequency of the frequency command ωi is limited, when the motor 1 is stopped or started from an extremely low speed, a slip corresponding to the limited frequency command ωiL occurs in the motor 1. If the slip generated in the electric motor 1 is larger than the slip frequency command ωsr, the torque of the electric motor 1 will be lower than the torque command Tqr.

  When the torque of the electric motor 1 is lower than the torque command Tqr, when the electric motor 1 is driven on the uphill gradient, the propulsive force of the electric vehicle due to the torque of the electric motor 1 loses the gravity caused by the upward gradient, and the electric vehicle may retreat. is there.

  An object of the present invention is to solve the above-described problems and to provide an electric vehicle control device that can prevent the electric vehicle from moving backward even when the electric vehicle is started uphill.

In order to solve the above problems, an electric vehicle control device according to the present invention is an electric vehicle control device that controls an electric motor that drives an electric vehicle, comprising: a current detector that detects a current flowing through the electric motor; A speed calculation unit that calculates a rotation speed of the motor based on a current detected by a motor and a voltage command that indicates an output voltage to the motor, a slip frequency command generation unit that generates a slip frequency command of the motor, An adder that generates a frequency command obtained by adding the rotation speed calculated by the speed calculation unit and the slip frequency command generated by the slip frequency command generation unit, and the adder according to the rotation direction of the electric motor. A frequency limiter that generates a limited frequency command by frequency-limiting the generated frequency command, and a magnetic flux command attenuation that generates an attenuated magnetic flux command that attenuates the magnetic flux command Based on a torque command and an attenuated magnetic flux command generated by the magnetic flux command attenuating unit, a current command generating unit that generates a magnetic flux component current command and a torque component current command, and a current detected by the current detector, A limiting frequency command generated by the frequency limiting unit, and a torque control unit that generates the voltage command based on a magnetic flux component current command and a torque component current command generated by the current command generating unit , flux command damping unit, based on said torque command and the limiting frequency command, that generates said attenuating magnetic flux command.

  Further, in the electric vehicle control device according to the present invention, the frequency limiter may correct the frequency command when the frequency indicated by the frequency command is equal to or less than a first positive threshold value when the electric motor rotates forward. When the frequency indicated by the frequency command is greater than or equal to a negative second threshold, the upper limit of the frequency command is limited to a negative value to generate the limited frequency command when the motor rotates in the reverse direction. The magnetic flux command attenuating section, when the frequency command is frequency-limited by the frequency limiting section, generates the attenuated magnetic flux command by attenuating the magnetic flux command, and the frequency command is not frequency-limited. In this case, it is desirable that the magnetic flux command be the damping magnetic flux command.

In the electric vehicle control device according to the present invention, when the damping magnetic flux command is IfrD, the secondary resistance of the electric motor is R2, the torque command is Tqr, and the limiting frequency command is ωiL, the magnetic flux command damping is performed. The part is the following formula
IfrD = √ (R2 * Tqr / ωiL)
It is desirable to generate the damping magnetic flux command based on the following .

  ADVANTAGE OF THE INVENTION According to the electric vehicle control apparatus which concerns on this invention, even at the time of starting on an ascending slope, retreat of an electric vehicle can be prevented.

It is a figure showing the example of composition of the electric car control device concerning a 1st embodiment of the present invention. FIG. 2 is a diagram illustrating a configuration example of a frequency limiting unit illustrated in FIG. 1. It is a figure showing the example of composition of the electric car control device concerning a 2nd embodiment of the present invention. FIG. 4 is a diagram illustrating a configuration example of a frequency limiting unit illustrated in FIG. 3. It is a figure showing the example of composition of the electric car control device concerning a 3rd embodiment of the present invention. FIG. 9 is a diagram illustrating a configuration example of an electric vehicle control device according to a conventional example.

  Hereinafter, embodiments of the present invention will be described.

(First embodiment)
FIG. 1 is a diagram illustrating a configuration example of an electric vehicle control device 100 according to the first embodiment of the present invention. 1, the same components as those in FIG. 6 are denoted by the same reference numerals, and description thereof will be omitted.

  The electric vehicle control device 100 shown in FIG. 1 differs from the electric vehicle control device 10 shown in FIG. 6 in that a frequency limiter 110 and a magnetic flux command attenuator 120 are added, a slip frequency command generator 14a, a current command The difference is that the generator 16a and the torque controller 17a are changed to a slip frequency command generator 14, a current command generator 16 and a torque controller 17, respectively.

  The torque command Tqr is input to the slip frequency command generator 14 and the current command generator 16. Further, the magnetic flux command Ifr is input to the magnetic flux command attenuator 120.

  The frequency limiting unit 110 generates a limited frequency command ωiL obtained by frequency-limiting the frequency command ωi output from the adder 15 according to the rotation direction of the electric motor 1, and outputs the limited frequency command ωiL to the torque control unit 17.

  FIG. 2 is a diagram illustrating a configuration example of the frequency limiting unit 110.

  The frequency limiting unit 110 illustrated in FIG. 2 includes a lower limit limiting unit 111, an upper limit limiting unit 112, and a switch 113.

  Frequency command ωi is input to lower limit limiting section 111 and upper limit limiting section 112.

  When the frequency indicated by the frequency command ωi is equal to or lower than the predetermined frequency ωi1 (> 0), the lower limit limiting unit 111 outputs the positive value a to the switch 113 as the limited frequency ωiL_F, and is indicated by the frequency command ωi. If the frequency is higher than the predetermined frequency ωi1, the switch 113 outputs the frequency indicated by the frequency command ωi as the limited frequency ωiL_F. That is, the lower limit limiting unit 111 limits the lower limit of the frequency command ωi by the positive value a and outputs the frequency command ωi to the switch 113 as the limited frequency ωiL_F. The frequency ωi1 is a value that causes the vehicle to run at low speed (including stopping) when the electric motor 1 rotates forward.

  When the frequency indicated by the frequency command ωi is smaller than the predetermined frequency ωi2 (<0), the upper limit limiting unit 112 outputs the frequency indicated by the frequency command ωi to the switch 113 as the limited frequency ωiL_R, and outputs the frequency command ωi Is higher than the predetermined frequency ωi2, the negative value b is output to the switch 113 as the limited frequency ωiL_R. That is, upper limiter 112 limits upper limit of frequency command ωi by negative value b, and outputs the same to switch 113 as limited frequency ωiL_R. The frequency ωi2 is a value that causes the vehicle to run at low speed (including stopping) when the electric motor 1 rotates in the reverse direction.

  The switch 113 receives the rotation direction command FR indicating the rotation direction of the motor 1, and limits the limit frequency ωiL_F output from the lower limit limit unit 111 when the motor 1 rotates forward based on the input rotation direction command FR. It outputs as the frequency command ωiL, and when the motor 1 rotates in the reverse direction, outputs the limited frequency ωiL_R output from the upper limit limiting unit 112 to the torque control unit 17 as the limited frequency command ωiL. The switch 113 may perform switching using the acceleration / deceleration command and the sign of the torque command Tqr.

  Therefore, when the frequency indicated by the frequency command ωi is equal to or higher than the positive frequency ωi1 (first threshold) during the forward rotation of the electric motor 1, the frequency limiter 110 limits the frequency command ωi to a lower limit with a positive value a, When the motor 1 rotates in the reverse direction, when the frequency indicated by the frequency command ωi is equal to or lower than the negative frequency ωi2, the motor control unit 1 generates a limited frequency command ωiL in which the upper limit of the frequency command ωi is limited by a negative value b, and outputs it to the torque control unit 17.

  Referring again to FIG. 1, the magnetic flux command attenuator 120 generates an attenuated magnetic flux command IfrD (indicating a magnetic flux smaller than the magnetic flux indicated by the magnetic flux command Ifr) that attenuates the magnetic flux command Ifr, and generates the slip frequency command generator 14. And the current command generation unit 16.

  The slip frequency command generator 14 generates a slip frequency command ωsr using the following equation (9) based on the torque command Tqr and the damped magnetic flux command IfrD output from the magnetic flux command attenuator 120, and generates an adder 15 Output to

  Based on the torque command Tqr and the attenuated magnetic flux command IfrD output from the magnetic flux command attenuating unit 120, the current command generating unit 16 uses the following equations (10) and (11) to calculate the magnetic flux component current command Id and the torque component A current command Iq is generated.

  As described above, the damped magnetic flux command IfrD is obtained by attenuating the magnetic flux command Ifr. Therefore, torque current command Iq generated based on damping magnetic flux command IfrD is larger than torque current command Iq (FIG. 6) generated based on magnetic flux command Ifr.

The torque control unit 17 includes a magnetic flux component current command Id and a torque component current command Iq output from the current command generation unit 16, a current i detected by the current detector 12, and a limiting frequency output from the frequency limiting unit 110. A voltage command V ^* is generated based on the command ωiL, and is output to the power converter 11 and the speed calculator 13.

As described above, when the motor 1 is rotating forward, the frequency indicated by the limit frequency command ωiL is equal to or higher than the positive value a, that is, is always a positive value. Also, when the motor 1 rotates in the reverse direction, the frequency indicated by the limit frequency command ωiL is equal to or less than the negative value b, that is, always a negative value. Therefore, the rotation direction of the electric motor 1 does not become opposite to the direction indicated by the rotation direction command FR. Therefore, even if an error occurs in the calculation speed ωmc, the voltage command V ^* for causing the electric motor 1 to output the torque in the reverse direction to the rotation direction command FR is not generated, and the vehicle moves in the desired traveling direction. Moving in the opposite direction can be suppressed.

In the present embodiment, a torque current command Iq generated based on the damping magnetic flux command IfrD is generated, and a voltage command V ^* is generated using the torque current command Iq. Therefore, the current flowing through the electric motor 1 becomes larger than when the magnetic flux command Ifr is used as it is, and the torque of the electric motor 1 increases. Therefore, it is possible to mitigate a decrease in torque caused by the frequency limiter 110 and prevent the electric vehicle from moving backward even when the electric vehicle is started on an uphill slope.

As described above, according to the present embodiment, the electric vehicle control device 100 calculates the current speed of the electric motor 1 based on the current detector 12 that detects the current i flowing through the electric motor 1 and the detected current i and the voltage command V ^*. a speed calculator 13 for calculating ωmc, a slip frequency command generator 14 for generating a slip frequency command ωsr, an adder 15 for generating a frequency command ωi obtained by adding the calculated speed ωmc and the frequency command ωsr, A frequency limiting unit 110 that generates a limited frequency command ωiL that limits the frequency command ωi according to the rotation direction, a magnetic flux command attenuating unit 120 that generates an attenuated magnetic flux command IfrD that attenuates the magnetic flux command Ifr, and a torque command Tqr A current command generating unit 16 that generates a magnetic flux component current command Id and a torque component current command Iq based on the damping magnetic flux command IfrD and the detected current i And a torque control unit 17 that generates a voltage command V ^* based on the limit frequency command ωiL, the magnetic flux component current command Id, and the torque component current command Iq.

By generating a torque component current command Iq based on the attenuated magnetic flux command IfrD obtained by attenuating the magnetic flux command Ifr, and generating the voltage command V ^* using the torque component current command Iq, the magnetic flux command Ifr can be used as it is. The current flowing through the motor 1 increases, and the torque of the motor 1 increases. Therefore, it is possible to mitigate a decrease in torque caused by the frequency limiting unit 110 and prevent the electric vehicle from moving backward even when the electric vehicle is started on an uphill slope.

(Second embodiment)
FIG. 3 is a diagram illustrating a configuration example of an electric vehicle control device 100A according to a second embodiment of the present invention. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and description thereof will be omitted.

  The electric vehicle control device 100A shown in FIG. 3 is different from the electric vehicle control device 100 shown in FIG. 1 in that the frequency limiting unit 110 and the magnetic flux command attenuating unit 120 are changed to a frequency limiting unit 110A and a magnetic flux command attenuating unit 120A, respectively. Is different.

  Frequency limiter 110A outputs signal LmtSt indicating whether or not frequency limitation (upper limit or lower limit) of frequency command ωi is performed to magnetic flux command attenuator 120A. In the following, the frequency limiter 110A sets the signal LmtSt = ON when the frequency command ωi is frequency-limited (ωiL ≠ ωi), and does not perform the frequency command ωi frequency limit (ωiL = ωi). ), The signal LmtSt = OFF.

  FIG. 4 is a diagram illustrating a configuration example of the frequency limiting unit 110A. 4, the same components as those in FIG. 2 are denoted by the same reference numerals, and description thereof will be omitted.

  The frequency limiter 110A shown in FIG. 4 differs from the frequency limiter 110 shown in FIG. 2 in that a comparator 114 is added.

  The comparator 114 receives the frequency command ωi and the limit frequency command ωiL, and compares the input frequency command ωi with the limit frequency command ωiL. When the frequency command ωi matches the limited frequency command ωiL, the comparator 114 determines that the frequency command ωi has not been subjected to the frequency limitation, and sets the signal LmtSt = OFF. When the frequency command ωi does not match the limited frequency command ωiL, the comparator 114 determines that the frequency command ωi is in the frequency limit state, and sets the signal LmtSt = ON.

  Referring again to FIG. 3, when the signal LmtSt = ON, the magnetic flux command attenuating unit 120A attenuates the magnetic flux command Ifr to generate and output an attenuated magnetic flux command IfrD. On the other hand, when the signal LmtSt = OFF, the magnetic flux command attenuating unit 120A outputs the magnetic flux command Ifr as it is as the damped magnetic flux command IfrD.

  As described above, according to the present embodiment, when the frequency limit of the frequency command ωi is performed by the frequency limiter 110A, the electric vehicle control device 100A attenuates the magnetic flux command Ifr to generate the damped magnetic flux command IfrD. However, when the frequency limitation of the frequency command ωi is not performed by the frequency limiting unit 110A, a magnetic flux command attenuation unit 120A that sets the magnetic flux command Ifr to the attenuation magnetic flux command IfrD is provided.

  Therefore, when the motor 1 accelerates and the restriction of the frequency command ωi becomes unnecessary, the damping magnetic flux command IfrD becomes equal to the magnetic flux command Ifr, and thus the torque of the motor 1 can be controlled according to the torque command Tqr.

(Third embodiment)
FIG. 5 is a diagram illustrating a configuration example of an electric vehicle control device 100B according to a third embodiment of the present invention. 5, the same components as those in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

  The electric vehicle control device 100B shown in FIG. 5 is different from the electric vehicle control device 100A shown in FIG. 3 in that the frequency limiting unit 110A and the magnetic flux command attenuating unit 120A are changed to a frequency limiting unit 110B and a magnetic flux command attenuating unit 120B, respectively. Is different.

  The frequency limiting unit 110B outputs the limited frequency command ωiL to the magnetic flux command attenuating unit 120B in addition to the signal LmtSt.

  The magnetic flux command attenuating unit 120B receives the torque command Tqr, and based on the input torque command Tqr and the limited frequency command ωiL output from the frequency limiting unit 110B, uses the following equation (12) to attenuate the amount of attenuated magnetic flux. Calculate IfrD0.

  When the signal LmtSt = ON, the magnetic flux command attenuator 120B outputs the calculated attenuation magnetic flux amount IfrD0 to the current command generator 16 as an attenuation magnetic flux command IfrD. On the other hand, when the signal LmtSt = OFF, the magnetic flux command attenuating unit 120B sets the magnetic flux command Ifr as it is as the damped magnetic flux command IfrD.

  As described above, according to the present embodiment, the electric vehicle control device 100B includes the magnetic flux command damping unit 120B that generates the damping magnetic flux command IfrD based on the limit frequency command ωiL and the torque command Tqr.

  Therefore, the magnetic flux component current command Id and the torque component current command Iq can be generated such that the slip frequency command ωsr is matched with the actual slip of the electric motor 1 and a torque close to the torque command Tqr is output.

  In the first embodiment, the magnetic flux command attenuator 120 calculates the amount of damped magnetic flux IfrD0 by using the equation (12), and outputs the obtained amount of damped magnetic flux IfrD0 to the current command generator 16 as the damped magnetic flux command IfrD. You may.

  Although the present invention has been described with reference to the drawings and embodiments, it should be noted that those skilled in the art can easily make various changes or modifications based on the present disclosure. Therefore, it should be noted that these variations or modifications are included in the scope of the present invention. For example, functions included in each block and the like can be rearranged so as not to be logically inconsistent, and a plurality of blocks can be combined into one or divided.

Reference Signs List 1 motor 11 power converter 12 current detector 13 speed calculation unit 14 slip frequency command generation unit 15 adder 16 current command generation unit 17 torque control unit 100, 100A, 110B electric vehicle control device 110, 110A, 110B frequency limit unit 111 Lower limiter 112 Upper limiter 113 Switch 114 Comparator 120, 120A, 120B Magnetic flux command attenuator

Claims (3)

An electric vehicle control device that controls an electric motor that drives an electric vehicle,
A current detector for detecting a current flowing through the motor,
A speed calculation unit that calculates the rotation speed of the motor based on the current detected by the current detector and a voltage command that indicates an output voltage to the motor;
A slip frequency command generation unit that generates a slip frequency command of the motor,
An adder that generates a frequency command obtained by adding the rotation speed calculated by the speed calculation unit and the slip frequency command generated by the slip frequency command generation unit;
According to the rotation direction of the electric motor, a frequency limiting unit that generates a limited frequency command frequency-limited the frequency command generated by the adder,
A magnetic flux command attenuating unit that generates an attenuated magnetic flux command by attenuating the magnetic flux command;
A current command generating unit that generates a magnetic flux component current command and a torque component current command based on a torque command and an attenuated magnetic flux command generated by the magnetic flux command attenuating unit;
Based on the current detected by the current detector, the limited frequency command generated by the frequency limiter, and the magnetic flux component current command and the torque component current command generated by the current command generator, the voltage command A torque control unit to generate;
Equipped with a,
The magnetic flux command damping unit, based on said limit frequency command and said torque command, the damping flux electric vehicle control device according to claim that you generate command. The electric vehicle control device according to claim 1,
The frequency limiting unit, when the motor is rotating forward, when the frequency indicated by the frequency command is equal to or less than a positive first threshold, the frequency command is limited to a lower limit with a positive value, and when the motor is rotating in reverse, When the frequency indicated by the frequency command is equal to or greater than a negative second threshold, the frequency command is generated by limiting the upper limit of the frequency command to a negative value to generate the limited frequency command,
The magnetic flux command attenuator generates the attenuated magnetic flux command by attenuating the magnetic flux command when the frequency command is frequency-limited by the frequency limiter, and the frequency command is not frequency-limited. , Wherein the magnetic flux command is the damped magnetic flux command.   The electric vehicle control device according to claim 1 or 2,
  Assuming that the damping magnetic flux command is IfrD, the secondary resistance of the electric motor is R2, the torque command is Tqr, and the limiting frequency command is ωiL, the magnetic flux command attenuating unit is represented by the following equation:
  IfrD = √ (R2 * Tqr / ωiL)
  An electric vehicle control device that generates the damping magnetic flux command based on the following.

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