JP4720636B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device that performs vector control of motor operation.

  As a motor control device that performs vector control of motor operation, PI control is performed using the current command value and the actual current actually flowing to the motor for the first term on the right side of each voltage equation shown in the following equations 1 and 2. By carrying out, the voltage command values Vd and Vq on the left side of the following equations 1 and 2 are obtained, and each switching element of the inverter for driving the motor is turned on and off based on the voltage command values Vd and Vq. There is something to make. (For example, see Patent Document 1)

  R is the resistance of the electric winding, p is the differential operator, ω is the angular velocity, Id is the d-axis current, Iq is the q-axis current, Ld is the d-axis inductance, Lq is the q-axis inductance, and Ke is the induced voltage constant. Show.

  In such a motor control device, the output voltage of the inverter is limited in the field-weakening region during power running or the region where the input voltage to the inverter is used more than the maximum value. At this time, in order to increase the torque, if the first term on the right side of Formula 2 above, that is, the voltage command value Vq on the left side of Formula 2 is increased by increasing the current command value of the q axis, the above number is relatively increased. The voltage command value Vd on the left side of 1 decreases, and the current flowing through the d-axis decreases. For this reason, the current that can be passed through the q-axis also decreases, and the torque is limited, which may prevent the torque from being increased to a desired value.

Therefore, in order to prevent the torque from being limited when setting the current command value in the field-weakening field region during power running or the region where the input voltage to the inverter is used more than the maximum value, There is a motor control device that sets a current command value in preference to a q-axis current command value. (For example, see Patent Document 2)
JP 2003-88193 A JP-A-9-74800

  However, as described above, in the motor control device that preferentially sets the d-axis current command value, the d-axis current command value is set from the detected voltage vector length based on the detected input voltage of the inverter, and then q Since the configuration is such that the current command value for the axis is set, for example, a configuration for determining the fluctuation amount of the current command value for the q-axis in accordance with the increase or decrease of the current command value for the d-axis is required. There is a problem of becoming.

  Therefore, an object of the present invention is to provide a motor control device that does not complicate motor control even if the d-axis current command value is set with priority.

In order to solve the above problems, the present invention adopts the following configuration.
That is, the motor control device of the present invention includes a first current command value setting means for setting a first current command value with respect to an input requested value, and a second current command value so as to follow the first current command value. A second current command value setting means for setting the second current command value setting means, the first current command value is compared with the previous second current command value, and the d-axis is increased or decreased. If priority is given to the d-axis, the d-axis second current command value is set closer to the d-axis first current command value than the previous d-axis second current command value. ON / OFF of each switching element of the inverter for driving the motor in accordance with the voltage command value, the priority determination unit for setting the voltage, the voltage command value setting unit for setting the voltage command value in accordance with the second current command value Switching control means for controlling

  This eliminates the need for a configuration for determining the fluctuation amount of the q-axis current command value according to the increase / decrease of the d-axis current command value as in the conventional motor control device described above. Even if priority is set, motor control can be prevented from becoming complicated.

The priority determination means may be configured to set the previous q-axis second current command value as the q-axis second current command value when giving priority to the d-axis.
When setting the d-axis with priority, by not changing the second current command value for the q-axis, the d-axis is reliably controlled with simple control.

  In addition, when the priority is given to the d-axis, the priority determination unit is configured to approach the d-axis first current command value according to the d-axis motor current value and the previous d-axis second current command value. The second current command value may be set.

  In addition, when the priority is given to the d-axis, the priority determination unit determines a fluctuation value according to the d-axis motor current value and the second d-axis current command value of the previous d-axis, and sets the fluctuation value to the previous d-axis. A value obtained by adding the second current command value may be set as the d-axis second current command value.

  The priority determination means may be configured to give priority to the d-axis when either the second current command value for the d-axis or the second current command value for the q-axis increases and the other decreases. Good.

  According to the present invention, in a motor control device that performs vector control, motor control can be prevented from becoming complicated even if the d-axis current command value is set with priority.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram illustrating a motor control device according to an embodiment of the present invention.
A motor control device 1 shown in FIG. 1 includes a rotor electrical angle calculation unit 2, a rotation speed calculation unit 3, an angular velocity calculation unit 4, a three-phase / two-phase conversion unit 5, a subtraction unit 6, and a PI control unit 7. And a map 8 (first current command value setting means), a current command value setting unit 9 (second current command value setting means), and an inverter control unit 10.

  The rotor electrical angle calculation unit 2 calculates the electrical angle θ of the rotor based on a position (for example, the U-phase axis) of the motor 11 based on a signal output from the electrical angle detection unit 12 provided in the motor 11. To do. The electrical angle detector 12 may be, for example, a resolver or a rotary encoder. The motor 11 may be a PM motor (Permanet Magnet Motor).

The rotational speed calculator 3 calculates the rotational speed V (r / min) of the rotor of the motor 11 based on the electrical angle θ and the rotational time of the rotor.
The angular velocity calculation unit 4 calculates the angular velocity ω (rad / s) based on the rotational speed V.

  The three-phase / two-phase conversion unit 5 calculates an electrical angle from a U-phase current Iu and a W-phase current Iw output from a current detection unit 14 provided between the motor 11 and an inverter 13 for driving the motor 11. Based on θ, the U-phase current Iu, the V-phase current Iv, and the W-phase current Iw that flow in each phase of the motor 11 are the actual current Id1 (d-axis motor current value) that flows in the d-axis direction of the motor 11 and the motor 11. To the actual current Iq1 flowing in the q-axis direction. In addition, the said current detection part 14 can consider a Hall element etc., for example.

  The subtraction unit 6 calculates a difference value Vdc3 between the voltage Vdc1 detected by the voltage detection unit 16 provided between the inverter 13 and the battery 15 and the required value Vdc2 input from the outside. Note that the voltage detector 16 may be a shunt resistor, for example.

The PI control unit 7 performs PI control on the difference value Vdc3 and outputs a torque command value T.
The map 8 includes a map command value Id2 (d-axis first current command value) and map command value Iq2 (q-axis first current) corresponding to the input torque command value T, the requested value Vdc2, and the rotation speed V. Command value) and field weakening current command value Id3 (d-axis current command value when torque is zero).

  The current command value setting unit 9 generates a current command value Id4 (a second current of the d-axis) based on the actual current Id1, the actual current Iq1, the map command value Id2, the map command value Iq2, and the field weakening current command value Id3. Command value) and current command value Iq4 (second current command value of q-axis) are set.

The inverter control unit 10 includes a voltage command value setting unit 17 (voltage command value setting unit) and a PWM control unit 18 (switching control unit).
The voltage command value setting unit 17 sets the voltage command value Vd and the voltage command value Vq based on the actual current Id1, the actual current Iq1, the current command value Id4, the current command value Iq4, and the angular velocity ω.

  For example, the voltage command value setting unit 17 multiplies the difference value between the actual current Id1 and the current command value Id4 by a constant Kp in the p (Proportional) term of the PI control calculation, and the actual current Id1 and the current command value Id4. A value corresponding to the first term of the right side of Equation 1 is obtained by adding the value obtained by multiplying the difference value of I by the constant Ki of the I (Integral) term of the PI control calculation, and the right side of Equation 1 is obtained from that value. The voltage command value Vd is set by subtracting the second term ωLqIq.

  For example, the voltage command value setting unit 17 multiplies the difference value between the actual current Iq1 and the current command value Iq4 by a constant Kp, and the difference value between the actual current Iq1 and the current command value Iq4 by a constant Ki. The value corresponding to the first term on the right side of the equation (2) is obtained by adding the calculated value to the value, and the second term ωLdId on the right side of the equation (2) and ωKe of the third term are added to the value. Set the value Vq.

  Based on the electrical angle θ, the voltage command value Vd, and the voltage command value Vq, the PWM control unit 18 applies PWM (Pulse Width Modulation) to each switching element of the inverter 13 (for example, IGBT (Insulated Gate Bipolar Transistor)). ) Drive signals S1 to S6 for turning on / off by control are output.

For example, the PWM control unit 18 adds the electrical angle θ and tan ⁻¹ (voltage command value Vq / voltage command value Vd) to thereby adjust the rotor position based on a certain position (for example, the U-phase axis) of the motor 11. The control phase is obtained, the fundamental wave for PWM control corresponding to the control phase is compared with the reference wave, and the drive signals S1 to S6 are output.

  Note that the inverter control unit 10 may turn on and off each switching element of the inverter 13 by control other than PWM control (for example, overmodulation control, 180-degree rectangular wave control, or the like).

FIG. 2 is a diagram showing the current command value setting unit 9.
The current command value setting unit 9 shown in FIG. 2 includes subtraction units 19 and 20, an Id variation value determination unit 21, an Iq variation value determination unit 22, subtraction units 23 and 24, a priority flag determination unit 25, a new A current command value determination unit 26 and command value storage units 27 and 28 are provided. Note that the priority determination means described in the claims is configured by, for example, a priority flag determination unit 25 and a new current command value determination unit 26.

The subtractor 19 calculates a difference value ΔId1 between the actual current Id1 and the previous current command value Id5 (previous d-axis second current command value).
The subtracting unit 20 calculates a difference value ΔIq1 between the actual current Iq1 and the previous current command value Iq5 (previous q-axis second current command value).

  The Id fluctuation value determining unit 21 determines a fluctuation value Id6 of the current command value Id4 based on the difference value ΔId1. The fluctuation value Id6 can be set arbitrarily. For example, the fluctuation value Id6 may be set so that the fluctuation value Id6 is 1A when the difference value ΔId1 is 0 to 3A, and the fluctuation value Id6 is 2A when the difference value ΔId1 is 4 to 6A.

  The Iq fluctuation value determining unit 22 determines the fluctuation value Iq6 of the current command value Iq4 based on the difference value ΔIq1. The variation value Iq6 can be arbitrarily set within a preset upper limit value. Thus, by providing the upper limit value for the fluctuation value Iq6, a sudden change in the current command value Iq4 is prevented. As a result, the voltage command value setting unit 17 prevents the output voltage of the inverter 13 from being saturated due to the gain (Kp, Ki, etc.) during the PI control calculation, and performs motor control with good response to the current command value Iq4. It can be carried out.

The subtracting unit 23 calculates a difference value ΔId2 obtained by subtracting the absolute value of the previous current command value Id5 from the absolute value of the map command value Id2.
The subtracting unit 24 calculates a difference value ΔIq2 obtained by subtracting the absolute value of the previous current command value Iq5 from the absolute value of the map command value Iq2.

The priority flag determination unit 25 outputs the priority flag F1 or the priority flag F2 based on the respective signs of the difference value ΔId2 and the difference value ΔIq2.
That is, the priority flag determination unit 25 outputs the priority flag F1 when the signs of the difference value ΔId2 and the difference value ΔIq2 are both positive or negative. The priority flag determination unit 25 also determines that the sign of the difference value ΔId2 is positive and the sign of the difference value ΔIq2 is negative, or the sign of the difference value ΔId2 is negative and the sign of the difference value ΔIq2 is positive. At this time, the priority flag F2 is output.

  The new current command value determination unit 26 determines the d-axis current based on the field weakening current Id3, the previous current command value Id5, the previous current command value Iq5, the fluctuation value Id6, the fluctuation value Iq6, and the priority flag F1 or F2. The command value Id4 and the q-axis current command value Iq4 are determined.

  That is, when the priority flag F1 is input, the new current command value determination unit 26 adds the previous current command value Iq5 and the fluctuation value Iq6 so that the current command value Iq4 approaches the map command value Iq2, and then the weakening field. The previous current command value Id5 and the fluctuation value Id6 are added so that the current command value Id4 approaches the map command value Id2 with the magnetic current Id3 as a lower limit value.

  Further, when the priority flag F2 is input, the new current command value determination unit 26 sets the field weakening current Id3 as a lower limit value and the current command value Id5 and the fluctuation value so that the current command value Id4 approaches the map command value Id2. After adding Id6, the previous current command value Iq5 and the fluctuation value Iq6 are added so that the current command value Iq4 approaches the map command value Iq2.

  When adding the previous current command value Id5 and the fluctuation value Id6, the current command value Id4 increases from the previous setting when the sign of the fluctuation value Id6 is positive, and when the sign of the fluctuation value Id6 is negative, the current command The value Id4 decreases from the previous setting.

  Further, when adding the previous current command value Iq5 and the fluctuation value Iq6, the current command value Iq4 increases from the previous setting when the sign of the fluctuation value Iq6 is positive, and when the sign of the fluctuation value Iq6 is negative, the current command The value Iq4 decreases from the previous setting.

The command value storage unit 27 stores the current command value Id4 and outputs the stored current command value Id4 as the previous current command value Id5 when the next current command value Id4 is set.
The command value storage unit 28 stores the current command value Iq4, and outputs the stored current command value Iq4 as the previous current command value Iq5 when the next current command value Iq4 is set.

  FIG. 3A is a diagram for explaining an example of a current command value setting operation in the current command value setting unit 9 at the time of regeneration, and FIG. 3B is a diagram in the current command value setting unit 9 at the time of power running. It is a figure for demonstrating an example of electric current command value setting operation | movement. 3A and 3B, the horizontal axis indicates the current command value Iq4, and the vertical axis indicates the current command value Id4. Point A indicates current command values Id4 and Iq4 (that is, previous current command values Id5 and Iq5) at the previous setting, and the tips of the thick arrows indicate map command values Id2 and Iq2. Of the thick arrows, the white arrow indicates the direction of torque fluctuation, and the hatched arrow indicates the direction of fluctuation of the rotational speed of the motor 11. The thin arrows indicate the setting order of the current command values Id4 and Iq4. Further, the command value setting operation in the current command value setting unit 9 is the same in both power running and regeneration.

(When the priority flag F1 is output from the priority flag determination unit 25)
First, the current command value setting unit 9 adds the previous current command value Iq5 and the fluctuation value Iq6 so that the current command value Iq4 becomes equal to the map command value Iq2, and outputs the added value as the current command value Iq4. The previous current command value Id5 is output as it is as the current command value Id4. Next, the current command value setting unit 9 outputs the previous current command value Iq5 as the current command value Iq4 as it is, and the previous current command value Id5 and the fluctuation value Id6 so that the current command value Id4 becomes equal to the map command value Id2. And the added value is output as a current command value Id4.

That is, the current command value setting unit 9 changes the current command value Id4 and the current command value Iq4 in the direction (1) shown in FIG. 3A or 3B (the difference value ΔId2 and the difference value ΔIq2). When both signs are positive), after increasing the current command value Iq4 (1-1), the current command value Id4 is increased (1-2). Thereby, the voltage Vdc rises while the torque of the motor 11 increases. Here, “increase” and “decrease” the current command value means to increase / decrease the current amount without changing the sign, and to increase / decrease the absolute value of the current value. (The same applies to the following)
Further, the current command value setting unit 9 changes the current command value Id4 and the current command value Iq4 in the direction (2) shown in FIG. 3A or 3B (the difference value ΔId2 and the difference value ΔIq2). When both signs are negative), the current command value Iq4 is decreased (2-1), and then the current command value Id4 is decreased (2-2). As a result, the voltage Vdc decreases while the torque of the motor 11 decreases.

(When the priority flag F2 is output from the priority flag determination unit 25)
First, the current command value setting unit 9 adds the previous current command value Id5 and the fluctuation value Id6 so that the current command value Id4 becomes equal to the map command value Id2, and outputs the added value as the current command value Id4. The previous current command value Iq5 is output as it is as the current command value Iq4. Next, the current command value setting unit 9 outputs the previous current command value Id5 as it is as the current command value Id4, and also the previous current command value Iq5 and the fluctuation value Iq6 so that the current command value Iq4 becomes equal to the map command value Iq2. And the added value is output as a current command value Iq4.

  That is, the current command value setting unit 9 changes the current command value Id4 and the current command value Iq4 in the direction (3) shown in FIG. 3A or 3B (the sign of the difference value ΔId2 is plus, When the sign of the difference value ΔIq2 is negative), after increasing the current command value Id4 (3-1), the current command value Iq4 is decreased (3-2). As a result, the voltage Vdc decreases while the rotational speed of the motor 11 increases.

  Further, the current command value setting unit 9 changes the current command value Id4 and the current command value Iq4 in the direction (4) shown in FIG. 3A or 3B (the sign of the difference value ΔId2 is minus, When the sign of the difference value ΔIq2 is positive), after decreasing the current command value Id4 (4-1), the current command value Iq4 is increased (4-2). As a result, the voltage Vdc increases while the rotational speed of the motor 11 decreases.

  When the current command values Id4 and Iq4 are brought closer to the map command values Id2 and Iq2, as described above, the current command values Id4 and Iq4 may be brought closer to the map command values Id2 and Iq2 at one time, or the current command values Id4 and Iq4 may be approximated to map command values Id2 and Iq2 by a plurality of times.

  As described above, when one of the current command value Id4 and the current command value Iq4 increases and the other decreases, the current command value Id4 is given priority using the predetermined map command values Id2 and Iq2. Even if Id4 and Iq4 are set, by setting the map command values Id2 and Iq2 to appropriate values, it is not necessary to adjust the current command value Iq4 after setting the current command value Id4. it can. Therefore, the motor control device 1 of the present embodiment requires a configuration for obtaining the variation amount of the q-axis current command value according to the increase / decrease of the d-axis current command value, as in the above-described conventional motor control device. Therefore, even if the current command value Id4 is set with priority, the motor control can be prevented from becoming complicated.

  Further, the motor control device 1 of the present embodiment decreases the current command value Iq4 after increasing the current command value Id4 when the rotation speed of the motor 11 during regeneration increases. Thereby, even if the rotation speed of the motor 11 is increased, the upper limit value of the voltage Vdc1 can be set first, so that the voltage Vdc can be prevented from becoming too higher than the voltage of the battery 15.

  Further, the motor control device 1 of the present embodiment increases the current command value Iq4 after decreasing the current command value Id4 when the rotation speed of the regenerative motor 11 decreases. Thereby, even if the rotation speed of the motor 11 decreases, the lower limit value of the voltage Vdc1 can be set first, so that the voltage Vdc1 can be prevented from becoming lower than the voltage of the battery 15.

  In this embodiment, the Iq fluctuation value determining unit 22 sets the magnitude of the fluctuation value Iq6 within the preset upper limit value. However, the Id fluctuation value determining unit 21 similarly sets the magnitude of the fluctuation value Id6 in advance. It may be within the upper limit set. In this case, a sudden change in the current command value Id4 is prevented. As a result, it is possible to prevent the output voltage from being saturated during the PI control calculation of the voltage command value setting unit 17.

It is a figure which shows the motor control apparatus of embodiment of this invention. It is a figure which shows an electric current command value setting part. (A) is a figure for demonstrating the electric current command value setting operation | movement at the time of regeneration. (B) is a figure for demonstrating the electric current command value setting operation | movement at the time of power running.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor controller 2 Rotor electrical angle calculation part 3 Rotational speed calculation part 4 Angular speed calculation part 5 3 phase / 2 phase conversion part 6 Subtraction part 7 PI control part 8 Map 9 Current command value setting part 10 Inverter control part 11 Motor 12 Electricity Angle detection unit 13 Inverter 14 Current detection unit 15 Battery 16 Voltage detection unit 17 Voltage command value setting unit 18 PWM control unit 19 Subtraction unit 20 Subtraction unit 21 Id fluctuation value determination unit 22 Iq fluctuation value determination unit 23 Subtraction unit 24 Subtraction unit 25 Priority flag determination unit 26 New current command value determination unit 27 Command value storage unit 28 Command value storage unit

Claims (5)

First current command value setting means for setting a first current command value for the input requested value;
Second current command value setting means for setting a second current command value so as to follow the first current command value;
It is arranged in the second current command value setting means, compares the first current command value with the previous second current command value, and determines the d-axis current command value from the setting of the q-axis current command value based on the increase / decrease. In the case where priority is given to setting of the d-axis current command value, the d-axis first current command value is brought closer to the previous d-axis second current command value. When the d-axis second current command value is set in the above and the setting of the d-axis current command value is not prioritized, the q-axis first current command value is brought closer to the previous q-axis second current command value. Priority determination means for setting the second current command value of the q-axis ,
Voltage command value setting means for setting a voltage command value according to the second current command value;
Switching control means for controlling on / off of each switching element of the inverter for driving the motor in accordance with the voltage command value;
A motor control device comprising: The motor control device according to claim 1,
The priority determination means sets the previous second current command value of the q-axis as the second current command value of the q-axis when giving priority to the setting of the d-axis current command value .
The motor control apparatus characterized by the above-mentioned. The motor control device according to claim 1,
When the priority determination means prioritizes the setting of the d-axis current command value, the d-axis first current command value depends on the d-axis motor current value and the previous d-axis second current command value. A second current command value for the d-axis is set so as to approach
The motor control apparatus characterized by the above-mentioned. The motor control device according to claim 1,
The priority determination means determines a fluctuation value according to the d-axis motor current value and the previous d-axis second current command value when priority is given to the setting of the d-axis current command value. A value obtained by adding the previous d-axis second current command value to the d-axis second current command value.
The motor control apparatus characterized by the above-mentioned. The motor control device according to claim 1,
The priority determination means gives priority to the setting of the d-axis current command value when one of the second current command value for the d-axis and the second current command value for the q-axis increases and the other decreases.
The motor control apparatus characterized by the above-mentioned.

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