JPWO2015083449A1 - Motor control device and control method - Google Patents

Abstract

The motor control device generates a current command value to the motor based on a motor constant and a torque command value corresponding to a predetermined temperature, and has a current control mode for controlling an applied voltage to the motor so as to follow the current command value. Voltage phase control mode that calculates the torque estimate value of the motor using the function to be executed and the motor constant corresponding to the predetermined temperature, and feedback operation of the voltage phase based on the deviation between the calculated torque estimate value and the torque command value And a function of executing The motor control device also determines switching of the control mode based on the magnitude relationship between the current command value and the detected current in the current control mode, and switches the control mode. The voltage amplitude command value in the voltage phase control mode is larger than the voltage amplitude in the current control mode in the application region of the voltage phase control mode, and is equal to or less than the voltage amplitude in the current control mode in the application region of the current control mode. .

Description

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

  Conventionally, a control device that controls an AC motor by selectively using voltage phase control and PWM current control is known. In the control device described in JP3683135B, it is disclosed that during voltage phase control, when the phase of the current detected by the current detector reaches a phase at which the torque / current ratio becomes maximum, switching to PWM current control is disclosed. .

  However, in the technology disclosed in JP3683135B, if there is a change in the temperature of the motor or manufacturing variations of the motor, even if the current phase is the same before and after switching from the voltage phase control to the PWM current control, the current amplitude and voltage The amplitudes do not match, and there is a possibility that a torque step will occur when switching control.

  An object of this invention is to provide the technique which suppresses generation | occurrence | production of the torque level difference at the time of switching from voltage phase control to electric current control.

  The motor control device according to one aspect of the present invention generates a current command value to the motor based on a motor constant and a torque command value corresponding to a predetermined temperature, and sets an applied voltage to the motor so as to follow the current command value. The current control mode for controlling the current control mode and the motor constant corresponding to the predetermined temperature are used to calculate the estimated torque value of the motor. Based on the deviation between the calculated estimated torque value and the torque command value, the voltage phase Based on the voltage phase control means for executing the voltage phase control mode for feedback operation and the magnitude relationship between the current command value and the detected current in the current control mode, the switching from the voltage phase control mode to the current control mode is determined. And a control mode for switching between control by the current control unit and control by the voltage phase control unit based on the determination result by the determination unit And a replacement means. The voltage amplitude command value in the voltage phase control mode is larger than the voltage amplitude realized in the current control mode in the application region of the voltage phase control mode, and the voltage realized in the current control mode in the application region of the current control mode. It is set to be less than the amplitude.

  Embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is a block diagram illustrating a configuration of an electric motor control device according to an embodiment. FIG. 2 is a block diagram illustrating processing performed inside the current control transition determination unit. FIG. 3 is a diagram that defines the relationship between the rotational speed N of the motor and the voltage amplitude command value V _a ^* in the voltage phase control mode. FIG. 4 is a diagram for explaining the behavior when the switching mode is switched by the conventional control device described in JP3683135B. FIG. 5 is a diagram for explaining the behavior when the switching mode is switched by the motor control device according to the embodiment. FIG. 6 is a flowchart showing control contents in the voltage phase control mode and the current control mode. FIG. 7 is a diagram illustrating an example of a control result by the motor control device according to the embodiment. FIG. 8 is a diagram for explaining a situation where the control mode is forcibly switched to the current control mode when the control mode is not switched from the voltage phase control mode to the current control mode even if the motor rotation speed is reduced to a predetermined rotation speed. is there.

  FIG. 1 is a block diagram illustrating a configuration of an electric motor control device according to an embodiment. This motor control device is applied to, for example, an electric vehicle. In addition to an electric vehicle, for example, the present invention can be applied to a hybrid vehicle or a system other than a vehicle.

The current command generator 1 determines the relationship between the torque command value T ^* , the DC voltage V _dc of the battery 7, and the rotation speed N (hereinafter referred to as motor rotation speed) N of the motor 9, and the d-axis current and the q-axis current. The determined table is stored, and the torque command value T ^* , the DC voltage V _dc of the battery 7 and the motor rotation speed N are input, and the d-axis current command value i _d ^* and The q-axis current command value i _q ^* is obtained. The d-axis current and the q-axis current defined in the table are a d-axis current and a q-axis current that obtain a desired torque when the motor temperature is 25 ° C. obtained in advance by experiment or analysis. The current command values i _d ^* and i _q ^* are current command values in the current control mode.

Various methods for generating the current command value have been proposed. For example, using the maximum efficiency method described in the following reference, it is calculated computationally using the motor constant at 25 ° C. It is also possible to ask for it.
References: "Practical motor drive control system design and practice", Chapter 7, Item 4, Haruo Naito, published by Japan Techno Center

The interference voltage generation unit 2 stores a table that defines the relationship between the torque command value T ^* , the DC voltage V _dc of the battery 7, the motor rotation speed N, and the d-axis and q-axis interference voltages. The command value T ^* , the DC voltage V _dc of the battery 7 and the motor rotational speed N are input, and the d-axis interference voltage V _{d_dcpl} ^* and the q-axis interference voltage V _{q _dcpl} ^* are obtained by referring to the above table.

The current vector controller 3 includes a d-axis current command value i _d ^* and a q-axis current command value i _q ^* , a d-axis current detection value i _d and a q-axis current command value i _q, and a d-axis interference voltage V _{d_dcpl} ^*. Based on the q-axis interference voltage V _{q_dcpl} ^* , vector current control by known non-interference control and current feedback control is performed to calculate the d-axis voltage command value V _di ^* and the q-axis voltage command value V _qi ^* . The voltage command values V _di ^* and V _qi ^* are voltage command values in the current control mode.

The voltage amplitude generation unit 13 obtains _a voltage amplitude command value V _a ^* in the voltage phase control mode by a method described later.

Torque calculator 15, the magnet flux _φ a_25 ℃ in motor temperature 25 ° C. which is previously stored, the inductance difference of the d-axis and q-axis in the motor temperature _{25 ℃ (L d -L q)} 25 ℃, and, d-axis current The command value i _d ^* and the q-axis current command value i _q ^* are input, and the estimated torque value T _cal of the electric motor 9 is calculated by the following equation (1).

In Equation (1), p is the number of pole pairs of the electric motor 9. Further, the inductance difference between the d-axis and the q-axis at the electric motor temperature of 25 ° C. (L _d −L _q ) ₂₅ ° C. is obtained by the inductance generator 14. Specifically, an offline analysis or experiment is performed in advance, and the torque command value T ^* , the DC voltage V _dc of the battery 7, the motor rotation speed N, and the d-axis and q-axis inductance difference (L _d −L _q ) Prepare a table that defines the relationship with ₂₅ ° C., input the torque command value T ^* , the DC voltage V _dc of the battery 7 and the motor rotation speed N, and refer to the above table to obtain the d axis And q-axis inductance difference (L _d −L _q ) of ₂₅ ° C.

The torque controller 16 inputs a difference between the torque command value T ^* and the estimated torque value T _cal and calculates a value obtained by PI amplification by the following equation (2) as a voltage phase command value α ^* . However, a K _p is a proportional gain in formula (2), K _i is an integral gain.

The dq-axis voltage generation unit 17 inputs the voltage amplitude command value V _a ^* obtained by the voltage amplitude generation unit 13 and the voltage phase command value α ^* calculated by the torque controller 16, and the following equation (3) The d-axis voltage command value V _dv ^* and the q-axis voltage command value V _qv ^* are calculated. The voltage command values V _dv ^* and V _qv ^* are voltage command values in the voltage phase control mode.

The current control transition determination unit 20 includes a d-axis current command value i _d ^* and a q-axis current command value i _q ^* obtained by the current command generation unit 1, and a d-axis current detection value i _d and a q-axis current command value i _q. And whether or not to shift from the voltage phase control mode to the current control mode is determined based on the magnitude relationship between the current command value and the detected current in the current control mode.

FIG. 2 is a block diagram illustrating processing performed inside the current control transition determination unit 20. The d-axis current command value i _d ^* and the q-axis current command value i _q ^* are subjected to filter processing corresponding to the normative response by the norm response filter 21 in consideration of the transient state, By _{obtaining the} sum of squares, _{ia_LPF} ² is calculated. Further, by calculating the sum of squares of the detected d-axis current value i _d and the q-axis current command value i _q , i _a ² is calculated. Then, as shown in Table 1, if i _{a_LPF} ² is larger than i _a ² , it is determined that the voltage phase control mode does not shift to the current control mode. If i _{a_LPF} ² is equal to or less than i _a ² , the voltage phase control mode is determined. Is determined to shift to the current control mode, and a control mode switching request is output.

The voltage phase control transition determination unit 19 performs transition determination from the current control mode to the voltage phase control mode. The threshold value T _ref set on the high rotation high torque side from the range where the switching from the voltage phase control mode to the current control mode occurs is stored in advance as a table using the motor rotation speed and the DC voltage of the battery 7 as an index, When the torque command value T ^* is equal to or greater than the threshold value T _ref obtained by referring to the table, it is determined that the current control mode is shifted to the voltage phase control mode and a control mode switching request is output.

  When the control mode switching request is output from the current control transition determination unit 20 or the voltage phase control transition determination unit 19, the control mode determination unit 21 outputs the control mode after switching to the control mode switch 18.

The control mode switch 18 is input from the control mode determination unit 21 among the voltage command values V _di ^* and V _qi ^* based on the current control mode and the voltage command values V _dv ^* and V _qv ^* based on the voltage phase control mode. A voltage command value corresponding to the control mode is selected and output to the dq axis / UVW phase converter 4 as the d axis voltage command value V _d ^* and the q axis voltage command value V _q ^* .

The dq-axis / UVW phase converter 4 calculates the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* based on the electrical angle θ of the rotor detected by the position detector 10 according to the following formula ( 4) is converted into three-phase voltage command values Vu *, Vv *, and Vw *.

The PWM converter 5 performs dead time compensation and voltage utilization rate improvement processing (both are publicly known), and power element drive signals of the inverter 6 corresponding to the three-phase voltage command values V _u ^* , V _v ^* , V _w ^*. D _{uu *} , D _{ul *} , D _{vu *} , D _{vl *} , D _{wu *} and D _{wl *} are generated.

A battery 7 is connected to the inverter 6, and the battery voltage V _dc is detected by a DC voltage sensor. The inverter 6 converts the DC voltage of the battery 7 from the pseudo AC voltages V _u , V _v , V _{wl *} , D _{wl *} , D _{vl *} , D _{wu *} , D _{wl *} based on the power element driving signals D _{uu *} , D _{ul *} , D _{vu *} , Convert to V _w and output.

The pseudo-alternating voltages V _u , V _v and V _w converted by the inverter 6 are applied to the electric motor 9. Current sensor 8, of the current flowing through each phase of the motor 9, any two-phase current, for example, detects the U-phase current i _u and the V-phase current i _v. The remaining one-phase current that is not detected, for example, the W-phase current i _w can be calculated based on the following equation (5).

The UVW phase / dq axis converter 12 is based on i _u , i _v detected by the current sensor 8 based on the electrical angle θ of the rotor of the electric motor 9 detected by the position detector 10, and Equation (5). The calculated i _w is converted into a d-axis current i _d and a q-axis current i _q based on the following equation (6).

  The rotational speed calculator 11 calculates the rotational speed N of the electric motor 9 from the amount of change per hour of the electrical angle θ detected by the position detector 10.

A method in which the voltage amplitude generation unit 13 obtains the voltage amplitude command value V _a ^* will be described.

FIG. 3 is a diagram defining the relationship between the rotational speed N of the electric motor 9 and the voltage amplitude command value V _a ^* in the voltage phase control mode. In FIG. 3, the voltage amplitude Va at the lowest temperature and the voltage amplitude Va at the highest temperature in the operation guarantee range of the electric motor 9 are shown together with the voltage amplitude Va in the current control mode at the reference temperature (25 ° C.). The control in the current control mode is performed in the low rotation region, and the control in the voltage phase control mode is performed in the high rotation region where the flux weakening control is performed.

  As shown in FIG. 3, in the current control mode, the voltage amplitude Va increases as the motor rotation speed increases, and the voltage amplitude Va reaches the upper limit when the rotation speed exceeds a certain rotation speed. The rate of increase of the voltage amplitude Va with respect to the increase in the motor rotation speed varies depending on the temperature of the electric motor 9, and the upper limit value of the voltage amplitude Va also varies depending on the temperature of the electric motor 9. Specifically, when the temperature is lower than the reference temperature, the increasing rate of the voltage amplitude Va is larger than the increasing rate of the voltage amplitude Va at the reference temperature, and the upper limit value of the voltage amplitude is the upper limit of the voltage amplitude at the reference temperature. Greater than the value. When the temperature is higher than the reference temperature, the rate of increase of the voltage amplitude Va is smaller than the rate of increase of the voltage amplitude Va at the reference temperature, and the upper limit value of the voltage amplitude is higher than the upper limit value of the voltage amplitude at the reference temperature. small.

In the motor rotation region to which the voltage phase control mode is applied, even if the voltage amplitude Va due to the current control mode fluctuates due to temperature changes and manufacturing variations of the motor 9, the voltage amplitude command value is always greater than the voltage amplitude Va. Set V _a ^* . In the motor rotation region to which the current control mode is applied, even if the voltage amplitude Va due to the current control mode fluctuates due to a temperature change or manufacturing variation of the electric motor 9, the voltage amplitude command value V is always kept below the voltage amplitude Va. _a Set ^* .

Referring to FIG. 3, in the current control mode, in the operation region a where the voltage amplitude Va at the reference temperature reaches the upper limit, a voltage amplitude command value V _a ^* exceeding the upper limit value of the voltage amplitude Va is generated. In the region b where the motor rotation speed is lower than the region a, a voltage amplitude command value V _a ^* lower than the voltage amplitude Va realized in the current control mode is generated. In the region b, even if the voltage amplitude Va in the current control mode changes due to a temperature change or manufacturing variation of the electric motor 9, the voltage amplitude command value V _a ^* is set so that the voltage amplitude Va does not fall below the voltage amplitude command value V _a ^*. Is set in advance. Thus, by setting the voltage amplitude command value V _a ^* so that the voltage amplitude is always reversed between the control modes, the magnitude of the current is also reversed between the control modes.

An experiment or analysis is performed in accordance with the above-described rules, and a table defining the relationship between the torque command value, the motor rotation speed, the DC voltage of the battery 7 and the voltage amplitude command value V _a ^* is prepared in advance. The voltage amplitude command value V _a ^* is obtained by referring to the table based on the value T ^* , the motor rotation speed N, and the DC voltage V _dc of the battery 7.

  It is also possible to calculate and obtain the minimum voltage amplitude realized in consideration of the temperature change and the manufacturing variation of the electric motor 9 from the current command value in the current control mode.

  FIG. 4 is a diagram for explaining the behavior when the switching mode is switched by the conventional control device described in JP3683135B. In the conventional control device, the control mode is switched from the voltage phase control mode to the current control mode when the phase of the detected current reaches a phase where the torque / current ratio becomes maximum.

  As described above, the voltage amplitude Va in the current control mode changes due to a temperature change or manufacturing variation of the electric motor 9. When there is no temperature change or manufacturing variation of the electric motor 9, the voltage amplitude Va does not change sharply when the control mode is switched. That is, when there is no temperature change or manufacturing variation of the electric motor 9, when the motor rotation speed decreases from the high rotation side, the voltage phase control mode is switched to the current control mode at the point P1, so the control mode is switched. Sometimes the voltage amplitude Va does not change sharply.

  On the other hand, when the temperature of the motor 9 is lower than the reference temperature (25 ° C.), the voltage phase control mode is switched from the voltage phase control mode to the current control mode at the point P2, so that the voltage amplitudes before and after switching of the control mode do not match. The voltage amplitude Va changes abruptly. When the temperature of the electric motor 9 is higher than the reference temperature (25 ° C.), the voltage amplitude Va changes sharply because the voltage phase control mode is switched to the current control mode at the point P3.

  In FIG. 4, even when the temperature of the motor 9 is the reference temperature, when there is a manufacturing variation of the motor 9, the point at which the voltage phase control mode is switched to the current control mode is changed from the point P <b> 1. A steep change in the voltage amplitude Va occurs.

FIG. 5 is a diagram for explaining the behavior when the switching mode is switched by the motor control device according to the embodiment. In the motor control apparatus according to the embodiment, even when there is a temperature change or manufacturing variation of the motor 9, if the motor rotation speed decreases, the voltage amplitude command value V _a ^* in the voltage phase control mode and the current There is a point where the voltage amplitude Va in the control mode matches. Further, the feedback control configuration allows torque fluctuation due to magnetic flux change. Further, the motor control device according to the embodiment determines the transition from the voltage phase control mode to the current control mode based on the current amplitude value. As a result, even when the temperature of the electric motor 9 is higher or lower than the reference temperature (25 ° C.) or when there is manufacturing variation of the electric motor 9, at the time of transition from the voltage phase control mode to the current control mode. Since the voltage amplitude command value V _a ^* in the voltage phase control mode matches the voltage amplitude Va in the current control mode, a sharp change in the voltage amplitude does not occur when the control mode is switched.

  In the example shown in FIG. 5, when the temperature of the electric motor 9 is the reference temperature (25 ° C.), when the motor rotation speed decreases from the high rotation side, the voltage phase control mode is switched to the current control mode at point P4, and the control is performed. The voltage amplitude Va does not change abruptly when the mode is switched. When the temperature of the motor 9 is lower than the reference temperature, the voltage phase control mode is switched to the current control mode at the point P5. When the temperature of the motor 9 is higher than the reference temperature, the voltage phase control is performed at the point P6. Switch from mode to current control mode. As shown in FIG. 5, even when the temperature of the electric motor 9 changes, a sharp change in voltage amplitude does not occur when switching from the voltage phase control mode to the current control mode.

  FIG. 6 is a flowchart showing control contents in the voltage phase control mode and the current control mode. If the current control mode is the voltage phase control mode, the process of step S10 is started. If the current control mode is the current control mode, the process of step S100 is started.

In step S10, torque command value T ^* , d-axis current command value i _d ^* and q-axis current command value i _q ^* , d-axis current detection value i _d and q-axis current command value i _q , rotor electrical angle θ The motor rotation speed N and the DC voltage V _dc of the battery 7 are acquired.

In step S20, i _a ² and i _{a_LPF} ² are calculated (see FIG. 2).

In step S30, i _a ² calculated in step S20 is equal to or _i a_LPF ² or more. If it is determined that i _a ² is greater than or _equal to i _{a_LPF} ² , the process proceeds to step S130 in order to switch the control mode from the voltage phase control mode to the current control mode. If it is determined that i _a ² is less than i _{a_LPF} ² , the process proceeds to step S40 in order to continue the processing in the voltage phase control mode.

In step S40, the voltage amplitude command value V _a ^* is calculated by the voltage amplitude generator 13, and the inductance difference between the d-axis and the q-axis (L _d −L _q ) ₂₅ ° C. is obtained by the inductance generator.

In step S50, the torque calculator 15 calculates the estimated torque value T _cal of the electric motor 9 from the equation (1).

In step S60, the torque controller 16 calculates the voltage phase command value α ^* from the equation (2) based on the difference between the torque command value T ^* and the estimated torque _Tcal .

In step S70, the dq-axis voltage generation unit 17 calculates the d-axis voltage command value V _dv ^* and the q-axis voltage command value from Equation (3) based on the voltage amplitude command value V _a ^* and the voltage phase command value α ^*. V _qv ^* is calculated. The control mode switch 18 converts the d-axis voltage command value V _dv ^* and the q-axis voltage command value V _qv ^* into the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* , and a dq-axis / UVW phase converter. 4 is output.

In step S80, the dq-axis / UVW phase converter 4 converts the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* into the three-phase voltage command values V _u ^* , V _v from equation (4). ^* , Converted to V _w ^* .

Next, processing in the current control mode will be described. In step S100, the torque command value T ^* , the d-axis current detection value i _d and the q-axis current command value i _q , the rotor electrical angle θ, the motor rotation speed N, and the DC voltage V _dc of the battery 7 are acquired.

In step S110, the voltage phase control transition determination unit 19 obtains a threshold value T _ref .

In step S120, it is determined whether or not the torque command value T ^* is greater than or equal to a threshold value _Tref . If it is determined that the torque command value T ^* is equal to or greater than the threshold value T _ref , the process proceeds to step S40 to shift the control mode from the current control mode to the voltage phase control mode. If it is determined that the torque command value T ^* is less than the threshold value T _ref , the process proceeds to step S130 in order to continue the current control mode process.

In step S130, the current command generator 1 determines the d-axis current command value i _d ^* and the q-axis current command value i _q ^* .

In step S140, the current vector controller 3 calculates the d-axis voltage command value V _di ^* and the q-axis voltage command value V _qi ^* . The control mode switching unit 18 converts the d-axis voltage command value V _di ^* and the q-axis voltage command value V _qi ^* into the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* as a dq-axis / UVW phase converter. 4 is output.

In step S150, the dq-axis / UVW phase converter 4 converts the d-axis voltage command value V _d ^* and the q-axis voltage command value V _q ^* into the three-phase voltage command values V _u ^* , V _v according to equation (4). ^* , Converted to V _w ^* .

  FIG. 7 is a diagram illustrating an example of a control result by the motor control device according to the embodiment. FIG. 7 shows control mode switching timing, voltage amplitude Va, and current amplitude Ia over time when the motor rotation speed increases and decreases while the torque command value remains constant.

  In the region where the motor rotation speed is low, the current control mode is applied. As the motor speed increases, the voltage amplitude Va also increases. When the voltage amplitude Va reaches the upper limit, the negative d-axis current is increased and field weakening control is performed, so that the current amplitude Ia increases and the increase in the voltage amplitude Va is suppressed.

When the motor rotation speed further increases and the timing of Ta is reached, the torque command value T ^* becomes equal to or greater than the threshold value _Tref , and the control mode is switched from the current control mode to the voltage phase control mode. When the mode is switched to the voltage phase control mode, the voltage amplitude Va is increased, so that the weakening current is decreased and the current amplitude Ia is decreased.

When the motor rotation speed changes from increase to decrease and the motor rotation speed decreases below a certain level, the voltage amplitude command value V _a ^* is decreased and the current amplitude decrease rate is suppressed. The amplitude of the command value approaches the amplitude of the current command value in current control. When the magnitude relationship is reversed at the timing of Tb, the control mode is switched from the voltage phase control mode to the current control mode.

  Since the torque of the electric motor 9 is a product of a magnetic flux vector and a current vector, when the magnet temperature of the electric motor 9 changes, the torque changes as the magnetic flux changes. In the current control, the current is controlled to be constant, but in the voltage phase control, since the current is not controlled, the current is also changed. Therefore, the voltage phase control mode and the current control mode have different torque sensitivities with respect to changes in the motor temperature.

  However, in the voltage phase control mode, the torque is estimated based on the same temperature condition as the precondition for generating the current command value in the current control mode, and the voltage phase is fed back, so that the sensitivity of the torque to the temperature change of the motor is achieved. Can be made equivalent to those in the current control mode, and the steady torque between the control modes can be made to coincide. The voltage amplitude command value in the voltage phase control mode is set so that the voltage amplitude intersects in the current control mode and the voltage phase control mode, and the current command value amplitude in the current control mode and the voltage phase control mode are detected. The voltage phase control mode is switched to the current control mode at the timing when the amplitude of the current that has been crossed. As a result, the motor torque, d-axis voltage and q-axis voltage, d-axis current and q-axis current can all be switched without any step, and torque steps and shocks associated with switching the control mode can be suppressed. it can.

  In the motor control device according to the present embodiment, even if the motor rotation speed falls to a predetermined rotation speed because the temperature and manufacturing variation of the motor 9 exceed the guaranteed operating range, the control mode changes from the voltage phase control mode to the current. If the control mode is not switched, the control for forcibly switching to the current control mode is also performed.

  FIG. 8 is a diagram for explaining a situation where the control mode is forcibly switched to the current control mode when the control mode is not switched from the voltage phase control mode to the current control mode even if the motor rotation speed is reduced to a predetermined rotation speed. is there. In FIG. 8, a line 81 indicates the voltage amplitude in the current control mode when the temperature of the electric motor 9 becomes a high temperature exceeding the guaranteed operating range.

As shown in FIG. 8, when the temperature of the electric motor 9 exceeds the guaranteed operating range, the voltage amplitude command value V _a ^* in the voltage phase control mode and the current control mode It does not intersect with the voltage amplitude command value Va (line 81). Therefore, in the method of switching to the current control mode based on the current amplitude (see Table 1), the voltage phase control mode does not switch to the current control mode even if the motor rotation speed decreases. However, when the control in the voltage phase control mode is continued in the low rotation region, the voltage that needs to be applied to the electric motor 9 becomes very small in the low rotation region, so it is difficult to ensure control accuracy. In addition, mechanical resonance that does not cause a problem in the current control mode may occur.

  Therefore, in the motor control device according to the present embodiment, if the control mode is not switched from the voltage phase control mode to the current control mode even if the motor rotation speed is reduced to the predetermined rotation speed, the current control mode is forcibly set. Switch to. If the temperature and manufacturing variation of the electric motor 9 are within the operation guarantee range, the predetermined rotation number is set in advance to an appropriate value based on the motor rotation number at which the voltage phase control mode is switched to the current control mode.

  As described above, the motor control device according to the embodiment generates a current command value to the motor 9 based on the motor constant and the torque command value corresponding to the predetermined temperature, and supplies the current to the motor 9 so as to follow the current command value. A torque estimation value of the motor 9 is calculated by using current control means (current command generator 1, current vector controller 3) for executing a current control mode for controlling the applied voltage, and a motor constant corresponding to a predetermined temperature. Based on the deviation between the estimated torque value and the torque command value, voltage phase control means (a torque calculator 15, a torque controller 16, a dq axis voltage generator 17) that executes a voltage phase control mode in which the voltage phase is feedback-operated. And determining means for determining switching from the voltage phase control mode to the current control mode based on the magnitude relationship between the current command value and the detected current in the current control mode Based on the determination result by the current control transition determination unit 20) and the determination unit, the control mode switching unit (control mode determination unit 21, control mode switch 18) for switching between the control by the current control mode or the control by the voltage phase control mode. With. The voltage amplitude command value in the voltage phase control mode is larger than the voltage amplitude realized in the current control mode in the application region of the voltage phase control mode, and the voltage realized in the current control mode in the application region of the current control mode. It is set to be less than the amplitude. As a result, there is a point where the current command value in the current control mode and the detected current value in the voltage phase control mode are reversed when the rotation speed of the electric motor 9 decreases from the high rotation side. At this point, the voltage phase control mode is switched to the current control mode. As described above, in the voltage phase control mode, the torque is estimated based on the same temperature condition as the precondition for generating the current command value in the current control mode, and the voltage phase is fed back, so that before and after the control mode switching. Therefore, the torque and current amplitude and phase, and the voltage amplitude and phase do not change before and after the control mode switching, and torque steps and shocks can be suppressed.

  In addition, in the motor control device according to the embodiment, if the determination to switch from the voltage phase control mode to the current control mode is not performed even when the rotation speed of the motor 9 is equal to or lower than the predetermined rotation speed, Thus, the voltage phase control mode is switched to the current control mode. As a result, it is possible to prevent a decrease in control accuracy that occurs when the voltage phase control mode is continued, and a mechanical resonance that does not cause a problem in the current control mode.

  The present invention is not limited to the above-described embodiments, and various modifications and applications are possible. For example, as an example of using the motor constant at 25 ° C. as the motor constant corresponding to the predetermined temperature, the example has been described, but the predetermined temperature is not limited to 25 ° C.

  This application claims the priority based on Japanese Patent Application No. 2013-250522 for which it applied to Japan Patent Office on December 3, 2013, and all the content of this application is integrated in this specification by reference.

Claims (3)

Current control for generating a current command value to the motor based on a motor constant and a torque command value corresponding to a predetermined temperature, and executing a current control mode for controlling a voltage applied to the motor so as to follow the current command value Means,
Executes a voltage phase control mode in which an estimated torque value of the motor is calculated using a motor constant corresponding to the predetermined temperature, and a voltage phase is feedback-operated based on a deviation between the calculated estimated torque value and the torque command value Voltage phase control means to
A determination unit for determining switching from the voltage phase control mode to the current control mode based on a magnitude relationship between a current command value and a detected current in the current control mode;
Control mode switching means for switching between control by the current control means and control by the voltage phase control means based on the determination result by the determination means;
With
The voltage amplitude command value in the voltage phase control mode is larger than the voltage amplitude realized in the current control mode in the application region of the voltage phase control mode, and the current control mode in the application region of the current control mode. Set to be below the voltage amplitude sometimes achieved,
Electric motor control device. The motor control device according to claim 1,
The control mode switching means is configured to determine whether to switch from the voltage phase control mode to the current control mode by the determination means even when the rotation speed of the electric motor is equal to or lower than a predetermined rotation speed. Regardless of the determination result by the determination means, switching from the control by the voltage phase control means to the control by the current control means,
Electric motor control device. An electric motor control method for controlling an electric motor by executing one of a current control mode and a voltage phase control mode,
Based on the magnitude relationship between the current command value and the detected current in the voltage phase control mode, determine switching from the voltage phase control mode to the current control mode,
Based on the result of the determination, select whether control by the current control mode or control by the voltage phase control mode,
When control by the current control mode is selected, a current command value for the motor is generated based on a motor constant and a torque command value corresponding to a predetermined temperature, and the motor is configured to follow the current command value. Run the current control mode to control the voltage applied to
When the control based on the voltage phase control mode is selected, an estimated torque value of the electric motor is calculated using an electric motor constant corresponding to the predetermined temperature, and a deviation between the calculated estimated torque value and the torque command value is calculated. Based on this, execute the voltage phase control mode to feedback the voltage phase,
The voltage amplitude command value in the voltage phase control mode is larger than the voltage amplitude realized in the current control mode in the application region of the voltage phase control mode, and the current control mode in the application region of the current control mode. Set to be below the voltage amplitude sometimes achieved,
Electric motor control method.

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