JP2017229127A - Device and method for controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress change in torque at a switching timing from voltage phase control to current vector control.SOLUTION: A method for controlling a motor executes: a current command value calculation step of calculating a current command value used for current vector control; a voltage command value calculation step of calculating a voltage command value; a selection step of selecting the current vector control or voltage phase control; and a voltage application step of applying an application voltage to a motor by the selected control method. The voltage command value calculation step includes: a phase calculation step of calculating a phase command value; a first estimation step of estimating a first torque on the basis of the current command value; a second estimation step of estimating a second torque on the basis of a value of a current flowing in the motor; and a correction step of correcting the phase command value so as to reduce a deviation between the first torque and the second torque, and calculating the voltage command value.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a motor control device and a control method.

  Known motor control methods include current vector control for controlling the magnitude of current flowing to the motor and voltage phase control for controlling the phase of the voltage applied to the motor. The current vector control and the voltage phase control are switched according to the operating state of the motor.

  In current vector control, a current command value is calculated based on a torque command value, and a voltage corresponding to the current command value is applied to the motor. In voltage phase control, a phase command value is calculated based on a torque command value, and a voltage corresponding to the phase command value is applied to the motor. Further, the estimated torque value is estimated based on the detected value of the current flowing through the motor, and the phase command value is feedback-controlled based on the deviation between the estimated torque value and the torque command value (for example, Patent Document 1).

JP 2013-192399 A

  Switching from the voltage phase control to the current vector control is performed when the d-axis current command value calculated in the current vector control exceeds the detected value of the d-axis current flowing to the motor. That is, the switching is performed when the current command value matches the current detection value on the d-axis.

  In the voltage phase control, the voltage applied to the motor is controlled by feedback control so that the torque command value and the estimated torque value coincide. However, when the above switching is performed, the current command value matches the current detection value on the d-axis, but it is guaranteed that the current command value matches the current detection value on the q-axis. Absent.

  For example, when the constant of the motor used for estimation of the estimated torque value is approximately equal to the actual motor constant, the estimated torque value substantially matches the actual torque. For this reason, at the switching timing, the current command value and the detected current value match on the d-axis, so the current command value and the actual current value also generally match on the q-axis. Therefore, at the switching timing, the difference between the current command value and the actual current value is extremely small on the d-axis and the q-axis. Therefore, the torque change due to the switching is less likely to occur.

  However, when the constant of the motor used for estimating the estimated torque value is significantly different from the actual motor constant, the estimated torque value is different from the actual torque. For this reason, even if the applied voltage is controlled so that the torque command value and the torque estimated value coincide with each other by feedback control, the torque command value is not appropriately controlled. Therefore, at the switching timing at which the switching from the voltage phase control to the current vector control is performed, the current command value and the current detection value coincide with each other on the d axis, but the current command value and the actual current on the q axis. It will no longer match the value.

  Thus, when the motor constant used for estimating the estimated torque value is significantly different from the actual motor constant at the switching timing, the current command value is different from the actual current value on the q-axis. Torque may change abruptly. Therefore, a change in torque occurs at the timing of switching from voltage phase control to current vector control.

  An object of the present invention is to suppress a change in torque at the switching timing from voltage phase control to current vector control.

  According to one aspect of the present invention, a motor control method includes a current command value calculation step for calculating a current command value used for current vector control according to a torque command value for the motor, and a voltage phase control according to the torque command value. A voltage command value calculating step for calculating a voltage command value to be used, a selection step for selecting current vector control or voltage phase control according to the motor operating state, and a command value used for the control selected by the selection step And a voltage applying step of applying an applied voltage to the motor. The voltage command value calculating step includes a phase calculating step for calculating a phase command value of the applied voltage according to the torque command value, and a first torque for estimating the torque generated in the motor as the first torque based on the current command value. Based on the estimation step, the second estimation step for estimating the torque generated in the motor as the second torque based on the value of the current flowing in the motor, and the deviation between the first torque and the second torque is reduced. A correction step of correcting the phase command value and calculating the voltage command value.

  A change in torque can be suppressed at the switching timing from voltage phase control to current vector control.

FIG. 1 is a schematic configuration diagram of a voltage supply device. FIG. 2 is a detailed configuration diagram of the current control transition determination unit. FIG. 3 is a detailed configuration diagram of the voltage phase control transition determination unit. FIG. 4 is a schematic configuration diagram of a main part of the voltage supply device. FIG. 5 is a schematic configuration diagram of a main part of a voltage supply device of a comparative example.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

(First embodiment)
FIG. 1 is a schematic configuration diagram of a voltage supply device according to the first embodiment. The voltage supply device 100 as in the present embodiment is a device that controls the rotational drive of the motor 200 mounted on the electric vehicle.

The voltage supply device 100 is a device that supplies the PWM voltage v _u , v _v , v _w corresponding to the target torque T ^* to the motor 200. The target torque T ^* is a torque command value determined according to the accelerator depression amount (accelerator opening) or the like. The voltage supply device 100 controls the rotational drive of the motor 200. The motor 200 is an example of a multiphase motor connected to the drive wheels of the vehicle, and operates in three phases in the present embodiment.

The voltage supply device 100 controls the rotation drive of the motor 200 by either the current vector control by the current vector control unit 10 or the voltage phase control by the voltage phase control unit 20. Switching between the current vector control and the voltage phase control is performed by the control mode switching unit 30 according to the operation state of the motor 200. When the control mode switching unit 30 outputs the d-axis voltage command value v _d ^* and the q-axis voltage command value v _q ^* to the motor control unit 40, the motor control unit 40 outputs the PWM voltages v _u and v _v. , V _w are output to the motor 200.

  The voltage supply device 100 is an example of a motor control device that executes a motor control method. The current vector control unit 10 is an example of a current command value calculation unit that performs a current command value calculation step. The voltage phase control unit 20 is an example of a voltage command value calculation unit that executes a voltage command value calculation step. The control mode switching unit 30 is an example of a selection unit that performs a selection step. The motor control unit 40 is an example of a voltage application unit that executes a voltage application step.

  Below, the detailed structure of each block is demonstrated. First, the configuration of the current vector control unit 10 will be described. The current vector control unit 10 includes a current command generation unit 11, a current vector controller 12, and an interference voltage generation unit 13.

The current command generator 11 stores a table in which the target torque T ^{* is associated} with the d-axis current command value i _d ^* and the q-axis current command value i _q ^* . This table is obtained in advance by experiment or analysis. The current command generation unit 11 uses this table to determine the d-axis current command value i _d ^* and the q-axis current command value i _q ^* according to the target torque T ^* input from outside the voltage supply device 100. These command values are obtained and output to the current vector controller 12. The current command generation unit 11 also outputs these command values to the first torque estimator 25A of the voltage phase control unit 20 and the current control transition determination unit 31 of the control mode switching unit 30.

The interference voltage generation unit 13 uses a table stored in advance, and according to the target torque T ^* , the d-axis non- _interacting voltage command value v _{d _dcpl} ^* and the q-axis non- _interacting voltage command value v seeking _q _ _dcpl ^*, and outputs these command values to the current vector controller 12. By doing in this way, the interference voltage which generate | occur | produces when an electric current flows in a dq axis is suppressed.

The current vector controller 12 includes a d-axis current command value i _d ^* , a q-axis current command value i _q ^* , a d-axis non- _interacting voltage command value v _{d _dcpl} ^* , and a q-axis non- _interacting voltage command value. v _{q — dcpl} ^* is input. Further, the d-axis current value i _d and the q-axis current value i _q indicating the current flowing through the motor 200 are input to the current vector controller 12 from the coordinate converter 41 of the motor control unit 40.

In response to these inputs, the current vector controller 12 calculates a d-axis voltage command value v _di ^* and a q-axis voltage command value v _qi ^* used for current vector control, and controls these voltage command values. The data is output to the control mode switch 34 of the mode switching unit 30. The current vector controller 12 also outputs these voltage command values to the voltage phase control transition determination unit 32 of the control mode switching unit 30. Note that the current vector controller 12 performs a general current vector control using a technique such as a known non-interference control or a current feedback control.

  Next, a configuration related to the voltage phase control unit 20 will be described. The voltage phase controller 20 includes a voltage amplitude converter 21, a dq-axis voltage generator 22, a voltage phase generator 23, an adder 24, a first torque estimator 25A, a second torque estimator 25B, a subtractor 26, and A PI calculator 27 is included.

  The voltage phase generation unit 23 is an example of a phase calculation unit that executes a phase calculation step. The first torque estimator 25A is an example of a first estimation unit that executes a first estimation step. The second torque estimator 25B is an example of a second estimation unit that executes a second estimation step. The subtractor 26 and the PI calculator 27 are an example of a correction unit that executes a correction step.

Based on the voltage detection value V _dc detected by the voltage sensor 42 of the motor control unit 40 and the command value modulation factor M ^* , the voltage amplitude conversion unit 21 calculates the voltage amplitude command value V _a ^* using the following equation. calculate. As the command value modulation rate M ^* , a predetermined value (for example, 1.1) according to the configuration of the motor 200 is used. Then, the voltage amplitude conversion unit 21 outputs the voltage amplitude command value V _a ^* to the dq axis voltage generation unit 22.

The voltage phase generator 23 includes a table obtained in advance by experiment or analysis, and a first voltage phase command used for voltage phase control according to the input target torque T ^* and the detected voltage value V _dc. Find the value α ₁ ^* . Then, the voltage phase generation unit 23 outputs the first voltage phase command value α ₁ ^* to the adder 24.

  The first torque estimator 25 </ b> A stores a table indicating the relationship between the d-axis and q-axis current values flowing to the motor 200 and the torque of the motor 200. In addition, this table shall be calculated | required by experiment or analysis.

The d-axis current command value i _d ^* and the q-axis current command value i _q ^* are input from the current command generation unit 11 to the first torque estimator 25A. First torque estimator 25A, based on these input values, using the table, calculates the norm torque command value T _ref ^*, and outputs the norm torque command value T _ref ^* to the subtracter 26. The reference torque command value T _ref ^* is a torque corresponding to the current command value in the current vector control unit 10.

The second torque estimator 25B stores the same table as the first torque estimator 25A. The second torque estimator 25B calculates an estimated torque T _est based on this table, the d-axis current value i _d output from the coordinate converter 41, and the q-axis current value i _q . The estimated torque T _est is a torque estimated from the current value of the motor 200.

  In the present embodiment, the same table is used for the first torque estimator 25A and the second torque estimator 25B, but the present invention is not limited to this. The first torque estimator 25A and the second torque estimator 25B may use substantially the same tables.

The subtractor 26 subtracts the estimated torque T _est from the reference torque command value T _ref ^*, and outputs a deviation as a result of the subtraction as a torque difference T _diff .

When PI calculator 27 receives torque difference T _diff (T _ref ^* −T _est ), PI calculator 27 performs PI amplification calculation using the following equation. Then, the PI calculator 27 outputs the PI calculation result to the adder 24 as the second voltage phase command value α ₂ ^* .

Here, K _p is a proportional gain, and K _i is an integral gain.

The adder 24 adds the first voltage phase command value α ₁ ^* and the second voltage phase command value α ₂ ^*, and sets the added value as the voltage phase command value α ^* to the dq-axis voltage generation unit 22. Output.

The dq-axis voltage generation unit 22 uses the following formula based on the input of the voltage amplitude command value V _a ^* and the voltage phase command value α ^* , and uses the following formula to determine the d-axis voltage command value v _dv ^* and the q-axis The voltage command value v _qv ^* is calculated. Then, the dq axis voltage generation unit 22 outputs these voltage command values to the control mode switch 34.

A voltage command value is input to the control mode switching unit 30 from the current vector control unit 10 and the voltage phase control unit 20. Then, the control mode switching unit 30 selects one of these voltage command values according to the control method, and uses the selected voltage command value as the d-axis voltage command value v _d ^* and the q-axis voltage command value. It outputs to the coordinate converter 43 as _vq ^* . The detailed configuration of the control mode switching unit 30 will be described later.

  Next, the motor control unit 40 will be described. The motor control unit 40 includes a coordinate converter 41, a voltage sensor 42, a coordinate converter 43, a PWM converter 44, an inverter 45, a battery 46, and a current sensor 47.

The coordinate converter 43 is a converter that performs coordinate conversion from the dq axis to the UVW phase. The coordinate converter 43 performs coordinate conversion of the d-axis voltage command value v _d ^* and the q-axis voltage command value v _q ^* using the following formula, and converts the conversion result into the three-phase voltage command values v _u ^* , v _v ^*, v PWM converter 44 is output as _w ^*.

The PWM converter 44 receives the three-phase voltage command values v _u ^* , v _v ^* , and v _w ^* from the coordinate converter 41 and the voltage detection value V _dc from the voltage sensor 42. The voltage sensor 42 is a sensor that detects a drive voltage from the battery 46 to the inverter 45. The PWM converter 44 corrects the three-phase voltage command values v _u ^* , v _v ^* , and v _w ^* by using a known dead time compensation technique, a voltage utilization ratio improvement technique, or the like. The PWM converter 44 generates drive signals D _uu ^* , D _ul ^* , D _vu ^* , D _vl ^* , D _wu ^* , and D _wl ^* to be used for driving the power element included in the inverter 45, and Output.

The inverter 45 is composed of three-phase six-arms and includes six power elements, two for each phase. The inverter 45 generates PWM voltages v _u , v _v , and v _w that are pseudo AC voltages by driving each of the power elements based on the drive signal output from the PWM converter 44. The inverter 45 supplies the PWM voltages v _u , v _v and v _w to the motor 200.

Since the motor 200 is driven in three phases, the inverter 45 and the motor 200 are connected by three wires corresponding to the three phases. The PWM voltage v _u is input to the motor 200 via the u-phase wiring, the PWM voltage v _v is input via the v-phase wiring, and the PWM voltage v _w is input via the w-phase wiring. The u-phase wiring is provided with a current sensor 47u, and the v-phase wiring is provided with a current sensor 47v. The u-phase current value i _u detected by the current sensor 47 _u and the v-phase current value i _v detected by the current sensor 47 _v are output to the coordinate converter 41.

Here, since the sum of i _u , i _v , and i _w , which are three-phase currents, becomes zero, the w-phase current value i _w can be expressed by the following equation.

  The coordinate converter 41 is a converter that performs coordinate conversion from the UVW phase to the dq axis by performing coordinate conversion represented by the following expression using Expression (5).

(6) As indicated formula, the coordinate converter 41, u-phase current value i _u, and, with respect to v-phase current value i _v, a coordinate conversion based on the electrical angle θ outputted from the rotation sensor 48 Do. Then, the coordinate converter 41 is a conversion result d-axis current value i _d, and the q-axis current value i _q, the current vectors controller 12, the second torque estimator 25B, and a current control shift determining unit 31 Output to.

  The rotation sensor 48 is provided adjacent to the motor 200 and detects the electrical angle θ of the rotor of the motor 200. The rotation sensor 48 outputs the detected electrical angle θ to the coordinate converters 41 and 43 and the rotation speed calculator 49.

  The rotation speed calculator 49 calculates the rotation speed N of the motor 200 from the amount of change of the electrical angle θ per time and outputs it to the outside of the voltage supply device 100.

  Next, a detailed configuration of the control mode switching unit 30 will be described. The control mode switching unit 30 includes a current control transition determination unit 31, a voltage phase control transition determination unit 32, a control mode determination unit 33, and a control mode switch 34.

The d-axis current command value i _d ^* , the q-axis current command value i _q ^* , the d-axis current value i _d , and the q-axis current value i _q are input to the current control transition determination unit 31. Based on these input values, the current control transition determination unit 31 determines switching from voltage phase control to current vector control, and outputs a signal Si indicating the determination to the control mode determination unit 33. The detailed configuration of the current control transition determination unit 31 will be described later with reference to FIG.

The detected voltage value V _dc , the d-axis voltage command value v _di ^* , and the q-axis voltage command value v _qi ^* are input to the voltage phase control transition determination unit 32. Based on these input values, voltage phase control transition determination unit 32 determines switching from current vector control to voltage phase control, and outputs a signal Sv indicating the determination to control mode determination unit 33. The detailed configuration of the voltage phase control transition determination unit 32 will be described later with reference to FIG.

  The control mode determination unit 33 selects either current vector control or voltage phase control based on the input signal Si and signal Sv, and outputs a signal S indicating the selected control method to the control mode switch 34. To do.

In accordance with the control method selected by the control mode determination unit 33, the control mode switch 34 converts the current vector control or voltage phase control command value into the d-axis voltage command value v _d ^* and the q-axis voltage command value. It outputs to the coordinate converter 43 as _vq ^* . Specifically, when current vector control is selected, the control mode switch 34 outputs the d-axis voltage command value v _di ^* and the q-axis voltage command value v _qi ^* . When the voltage phase control is selected, the control mode switch 34 outputs the d-axis voltage command value v _dv ^* and the q-axis voltage command value v _qv ^* .

  FIG. 2 is a diagram illustrating a detailed configuration of the current control shift determination unit 31. The current control transition determination unit 31 includes blocks 311A and 311B corresponding to a normative response considering a transient state, and a current vector comparison unit 312. Note that the filters of the blocks 311A and 311B are represented by the following equations.

When receiving an input of the d-axis current command value i _d ^* from the current command generation unit 11, the block 311 </ _b ^> A performs a filtering process on the input value and outputs the filtered command value to the current vector comparison unit 312. . When the block 311B receives an input of the q-axis current command value i _q ^* from the current command generation unit 11, the block 311B performs a filtering process on the input value and outputs the filtered command value to the current vector comparison unit 312. .

The current vector comparison unit 312 receives the d-axis current value i _d and the q-axis current value i _q from the coordinate converter 41 in addition to the inputs from the blocks 311A and 311B. Then, the current vector comparison unit 312 determines whether or not to request a shift to current vector control using the following table. Then, the current vector comparison unit 312 outputs a signal Si indicating the presence / absence of the request.

Table 1 is an example of a determination condition for determining whether or not there is a request to shift to current vector control. According to Table 1, when the d-axis current value i _d is smaller than the d-axis current command value i _d ^* , the current vector comparison unit 312 does not request a shift to current vector control. On the other hand, when the d-axis current value i _d is equal to or greater than the d-axis current command value i _d ^* , the current vector comparison unit 312 requests a shift to current vector control. In this manner, the request for shifting to the current vector control is determined based on the magnitude relationship between the d-axis current value i _d and the d-axis current command value i _d ^* .

  Here, the transition condition from voltage phase control to current vector control will be described. When the motor 200 is in the high rotation region, voltage phase control is performed because there is a possibility that sufficient electric power cannot be applied by the current vector control. On the other hand, when the motor 200 is in the high rotation region, the voltage applied to the motor is saturated, so that a weak magnetic flux that weakens the magnetic flux of the permanent magnet is generated by applying a negative d-axis current. Weak field control is performed.

That is, when the d-axis current value i _d is smaller than the d-axis current command value i _d ^*, field-weakening control in which a negative d-axis current is applied is performed, and it is determined that the region is in the high rotation region. Perform voltage phase control. On the other hand, when the d-axis current value i _d is equal to or greater than the d-axis current command value i _d ^*, it is determined that the high-rotation region where the field-weakening control is performed is performed, so the voltage phase control is changed to the current vector control. Migration is required.

  The determination condition for the request to shift to current vector control is not limited to the example shown in Table 1. As in the example shown in the following table, determination may be made using a condition corresponding to the operating point of the motor 200 using the q-axis current.

  In Table 2, conditions differ depending on whether the operating point of the motor 200 is in a power running state or a regenerative state. This is because the q-axis current also changes when field control is performed, but the increase / decrease direction of the q-axis current differs depending on the operating point of the motor 200.

When the operating point is power running, when the q-axis current value i _q is larger than the q-axis current command value i _q ^* , the shift to the current vector control is not required. On the other hand, when the q-axis current value i _q is equal to or less than the q-axis current command value i _q ^* , the shift to the current vector control is required.

When the operating point is regenerative and the q-axis current value i _q is smaller than the q-axis current command value i _q ^* , the transition to the current vector control is not required. On the other hand, when the q-axis current value i _q is equal to or greater than the q-axis current command value i _q ^* , a shift to current vector control is required.

FIG. 3 is a diagram illustrating a detailed configuration of the voltage phase control transition determination unit 32. The voltage phase control transition determination unit 32 receives the d-axis voltage command value v _di ^* and the q-axis voltage command value v _qi ^* from the current vector controller 12, and receives the voltage detection value V _dc from the voltage sensor 42. Entered. The voltage phase control transition determination unit 32 includes blocks 321A, 321B, and 321C, a norm calculation unit 322, and a voltage norm comparison unit 323.

In block 321A, the d-axis voltage command value v _di ^* is squared. Similarly, in the block 321B, the q-axis voltage command value v _qi ^* is squared. The norm calculation unit 322 outputs the sum of these square values as a voltage norm value V _a ^{* 2} .

In block 321C, the square value of the voltage detection value V _dc is obtained. Then, the voltage norm comparison unit 323 determines whether or not to shift to voltage phase control using the following table. Then, the voltage norm comparison unit 323 outputs a signal Sv indicating the presence / absence of this request.

Voltage norm value V _a ^{* 2,} if below the reference norm value "V _dc ^2/2" which is half the value of the square values of the voltage detection value V _dc, the voltage norm comparator unit 323, to the voltage phase control Do not require migration. On the other hand, when the voltage norm value V _a ^{* 2} is greater than or equal to the reference norm value, the voltage norm comparison unit 323 requests a shift to voltage phase control.

Here, conditions for determining a request to shift to voltage phase control will be described. When current vector control is performed, the voltage norm value V _a ^{* 2} determined based on the voltage command value changes according to the target torque T ^* . However, the voltage norm value V _a ^{* 2} of the voltage applied to the motor 200 in the current vector control depends on the magnitude of the voltage detection value V _dc supplied to the inverter 45, and the upper limit value is the reference norm value. .

Therefore, when the voltage norm value V _a ^{* 2} is lower than the reference norm value, it is determined that the current vector control can be appropriately performed, and the shift to the voltage phase control is not required. If the voltage norm value V _a ^{* 2} is greater than or equal to the reference norm value, it is determined that current vector control may not be performed properly, and a shift to voltage phase control is required.

  Hereinafter, the point that the change in torque of the motor 200 is suppressed when the switching from the voltage phase control to the current vector control is performed by the above-described configuration will be described with reference to FIGS. 4 and 5.

  FIG. 4 is a schematic configuration diagram of a main part of the voltage supply device 100. In this figure, only the main part of the configuration other than the voltage phase control unit 20 is shown.

In the voltage phase control unit 20, the first torque estimator 25A is based on the d-axis current command value i _d ^* and the q-axis current command value i _q ^* calculated in the current vector control unit 10. A reference torque command value T _ref ^* is calculated. The second torque estimator 25B calculates an estimated torque T _est based on the d-axis current value i _d and the q-axis current value i _q which are actual current values in the motor 200.

As shown in Table 1, when the d-axis current value i _d exceeds the d-axis current command value i _d ^* , switching from voltage phase control to current vector control is required. Therefore, the d-axis current command value i _d ^* coincides with the d-axis current value i _{d at the} timing of switching from the voltage phase control to the current vector control.

Further, the PI calculator 27 controls the reference torque command value T _ref ^* and the estimated torque T _est to coincide with each other. Therefore, the reference torque command value T _ref ^* is equal to the estimated torque T _est . Therefore, at the timing of switching from voltage phase control to current vector control, the reference torque command value T _ref ^* and the estimated torque T _est are equal, so the d-axis current value i _d is equal to the d-axis current command value i _d ^*. .

In the first torque estimator 25A and the second torque estimator 25B, when the d-axis current value and the q-axis current value are input, the torque is estimated. The tables used for calculating these torques are the same. The reference torque command value T _ref ^* that is the estimation result is controlled to be equal to the estimated torque T _est , and the d-axis current value i _d and the d-axis current command value i _d that are one of the inputs are controlled. ^* Is equal. Therefore, the q-axis current command value i _q ^* , which is the other input, is equal to the q-axis current value i _q .

  Therefore, at the timing of switching from voltage phase control to current vector control, the actual current value matches the current command value on the d-axis and the q-axis. Therefore, a change in torque of the motor 200 can be suppressed.

FIG. 5 is a schematic configuration diagram of a main part of the voltage supply device 100 used for comparison. Compared with the main part of the voltage supply apparatus 100 shown in FIG. 4, the voltage supply apparatus 100 in this figure has the first torque estimator 25 </ b ^{> A} deleted, and the target torque T ^* is input to the subtractor 26. The point is different.

The PI calculator 27 controls the target torque T ^* and the estimated torque T _est to coincide. Further, as described above, the d-axis current value i _d matches the d-axis current command value i _d ^{* at the} timing of switching from the voltage phase control to the current vector control.

Here, when the table used for torque estimation in the second torque estimator 25B appropriately indicates the actual state of the motor 200, the estimated torque T _est substantially coincides with the actual torque. Therefore, if the d-axis current command value i _d ^* matches the d-axis current value i _d , the q-axis current command value i _q ^* is approximately equal to the actual q-axis current value i _q .

After the voltage phase control is switched to the current vector control, the control is performed using the d-axis current command value i _d ^* and the q-axis current command value i _q ^* . As described above, since the current command value is substantially equal to the actual current value for both the d-axis and the q-axis, the torque of the motor 200 does not change significantly at the switching timing.

However, if the table in the second torque estimator 25B does not appropriately indicate the actual state of the motor 200, the estimated torque T _est will deviate from the actual torque.

At the switching timing, the d-axis current command value i _d ^* coincides with the d-axis current value i _d . However, even if the feedback control is performed so that the target torque T ^* and the estimated torque T _est match, the target torque T ^* is different from the actual torque. For this reason, the shaft current command value i _q ^* deviates from the q-axis current value i _q . Therefore, at the timing of switching from voltage phase control to current vector control, the torque of the motor 200 may change abruptly due to this deviation.

  As described above, in the present embodiment, the configuration as shown in FIG. 4 can suppress the change in the torque of the motor 200 at the timing when the voltage phase control is switched to the current vector control.

  In the present embodiment, the first torque estimator 25A and the second torque estimator 25B calculate the torque according to the d-axis current and the q-axis current, but the present invention is not limited to this. Further, the torque may be calculated according to the rotation state of the motor 200 such as the temperature of the motor 200 and the rotation speed of the motor 200. In this way, since the accuracy of torque estimation is increased, switching from voltage phase control to current vector control can be performed smoothly.

  In the present embodiment, the first torque estimator 25A and the second torque estimator 25B estimate the torque using the same table, but the present invention is not limited to this. Even if the first torque estimator 25A and the second torque estimator 25B have substantially the same table, a change in torque can be suppressed at the switching timing from the voltage phase control to the current vector control.

  According to the present embodiment, the following effects can be obtained.

  According to the embodiment of the present invention, the current command value calculation step by the current vector control unit 10, the voltage command value calculation step by the voltage phase control unit 20, the selection step by the control mode switching unit 30, and the motor control unit 40 And a voltage applying step. The voltage command value calculation step includes a phase calculation step by the voltage phase generator 23, a first estimation step by the first torque estimator 25A, a second estimation step by the second torque estimator 25B, a PI calculator 27, and And a voltage command value calculation step by the adder 24.

  In the first estimation step, the first torque is estimated by performing a first estimation process on the current command value calculated in the current command value calculation step. In the second estimation step, the second torque is estimated by performing the second estimation process on the actual current value flowing through the motor 200.

  For example, on the d axis, when the current command value exceeds the actual current value flowing through the motor 200, switching from voltage phase control to current vector control is performed. Therefore, at this switching timing, the current command value becomes equal to the actual current value on the d axis.

  Further, the torque obtained from the current command value by the first torque estimator 25A and the torque obtained from the actual current value flowing through the motor 200 by the second torque estimator 25B by performing the correction step are: Control is made to be substantially equal to each other.

  If attention is paid to the first torque estimator 25A that performs the first estimation process and the second torque estimator 25B that performs the second estimation process, the torque that is the output value is substantially equal. The current command value is equal to the actual current value. For this reason, the current command value on the q axis is equal to the actual current value. Therefore, when the voltage phase control is switched to the current vector control, the current command value becomes equal to the actual current value in both the d-axis and the q-axis, so that a rapid change in torque is suppressed. .

  Further, according to the embodiment of the present invention, the first torque estimator 25A that performs the first estimation process and the second torque estimator 25B that performs the second estimation process include the same or substantially the same table. Here, the torque output from these estimated values is controlled by the PI calculator 27 to be equal. At the timing of switching from voltage phase control to current vector control, the d-axis current command value, which is one input to these estimators, is equal to the measured value. Therefore, the q-axis current command value, which is the other input to these estimators, is equal to the measured value. Therefore, since the difference between the current command value and the actual current value can be made smaller on the d-axis and the q-axis, a change in torque can be suppressed.

  According to the embodiment of the present invention, in the selection step, the current vector control is selected when the current value in the motor on the d-axis exceeds the current command value. By doing so, the d-axis current command value and the measured value substantially coincide with each other at the timing of switching from the voltage phase control to the current vector control. Therefore, since the difference between the current command value and the actual current value can be made smaller on the d-axis and the q-axis, a change in torque can be suppressed.

  Further, according to the embodiment of the present invention, in the first torque estimator 25A that performs the first estimation process and the second torque estimator 25B that performs the second estimation process, the temperature, rotation speed, and the like of the motor 200 are further increased. The torque is estimated according to the rotation state of the motor 200. By doing in this way, since the estimation accuracy of torque improves, the motor 200 can be controlled more accurately.

  In addition, the example shown in this embodiment does not limit the current command value generation method and the torque estimation method, and can be applied to any method. Therefore, the same effect can be obtained even if different methods are used.

  The embodiment of the present invention has been described above. However, the above embodiment only shows a part of application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent. Moreover, the said embodiment can be combined suitably.

DESCRIPTION OF SYMBOLS 10 Current vector control part 11 Current command generation part 12 Current vector controller 13 Interference voltage generation part 20 Voltage phase control part 21 Voltage amplitude conversion part 22 dq axis voltage generation part 23 Voltage phase generation part 24 Adder 25A 1st torque estimator 25B Second torque estimator 26 Subtractor 27 PI calculator 30 Control mode switching unit 31 Current control transition determining unit 32 Voltage phase control transition determining unit 33 Control mode determining unit 34 Control mode switching unit 40 Motor control unit 100 Voltage supply device 200 motor

Claims (6)

A current command value calculating step for calculating a current command value used for current vector control according to a torque command value for the motor;
A voltage command value calculating step for calculating a voltage command value used for voltage phase control according to the torque command value;
A selection step of selecting the current vector control or the voltage phase control according to the operating state of the motor;
A voltage application step of applying an applied voltage to the motor in accordance with a command value used for control selected in the selection step,
The voltage command value calculation step includes:
A phase calculating step of calculating a phase command value of the applied voltage according to the torque command value;
A first estimating step for estimating a torque generated in the motor as a first torque based on the current command value;
A second estimating step of estimating a torque generated in the motor as a second torque based on a current value flowing through the motor;
A motor control method comprising: a correction step of correcting the phase command value and calculating the voltage command value so that a deviation between the first torque and the second torque is small. A motor control method according to claim 1, comprising:
The same estimation process is performed in the first estimation step and the second estimation step.
Motor control method. The motor control method according to claim 1 or 2,
In the selection step, when the current in the motor exceeds the current command value, the current vector control is selected.
Motor control method. A motor control method according to any one of claims 1 to 3,
In the first estimation step and the second estimation step, a motor torque is further estimated based on the state of the motor.
Motor control method. The motor control method according to claim 4,
The state of the motor is at least one of the temperature of the motor and the rotational speed.
Motor control method. A current command value calculation unit that calculates a current command value used for current vector control according to a torque command value for the motor;
A voltage command value calculation unit for calculating a voltage command value used for voltage phase control according to the torque command value;
A selection unit that selects the current vector control or the voltage phase control according to the operation state of the motor;
A voltage application unit that applies an applied voltage to the motor according to a command value used for control selected in the selection unit, and a motor control device comprising:
The voltage command value calculator is
A phase calculation unit that calculates a phase command value of the applied voltage according to the torque command value;
A first estimating unit that estimates torque generated in the motor as a first torque based on the current command value;
A second estimation unit configured to estimate a torque generated in the motor as a second torque based on a current value flowing through the motor;
A motor control device comprising: a correction unit that corrects the phase command value and calculates the voltage command value so that a deviation between the first torque and the second torque is small.

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