JP7151872B2 - Controller for permanent magnet synchronous machine - Google Patents

Description

The present invention relates to a control device for a permanent magnet synchronous machine.

Patent Literature 1 discloses an example of a control method for a permanent magnet synchronous motor. In the method the position of the rotor is corrected by a phase correction value. Phase correction values are calculated during tuning after the motor is installed.

Japanese Patent No. 3336870

However, in Patent Document 1, the phase correction value is calculated by measuring the driving voltage. Therefore, the controller requires a voltage sensor to measure the drive voltage. This complicates the hardware configuration of the control device.

The present invention was made to solve such problems. SUMMARY OF THE INVENTION An object of the present invention is to provide a control device for a permanent magnet synchronous machine that can calculate correction values for magnetic pole positions with a simple configuration.

A control apparatus for an electric motor according to the present invention includes a current command generator that generates command values for a d-axis current and a q-axis current of a permanent magnet synchronous machine; a current control unit for calculating command values for the d-axis voltage and the q-axis voltage of the current control unit; a first correction phase calculation unit for calculating a first correction phase based on the command value for the d-axis voltage calculated by the current control unit; a second correction phase calculation unit for calculating a second correction phase based on at least one of the command value of the q-axis current calculated by the control unit and the actual value of the q-axis current of the permanent magnet synchronous machine and parameters of the permanent magnet synchronous machine; and a conversion unit that performs coordinate conversion on dq coordinates in the current control unit using the electrical angle of the permanent magnet synchronous machine corrected by the third correction phase that is the sum of the first correction phase and the second correction phase. , provided.

According to the present invention, a control device includes a current command generation section, a current control section, a first correction phase calculation section, a second correction phase calculation section, and a conversion section. The current command generator generates command values for d-axis current and q-axis current of the permanent magnet synchronous machine. The current control unit receives the command values generated by the current command generation unit and calculates command values for the d-axis voltage and the q-axis voltage of the permanent magnet synchronous machine. The first corrected phase calculator calculates the first corrected phase based on the command value of the d-axis voltage calculated by the current controller. The second correction phase calculation unit calculates a second correction phase based on at least one of the command value of the q-axis current calculated by the current control unit and the actual value of the q-axis current of the permanent magnet synchronous machine and parameters of the permanent magnet synchronous machine. Calculate The conversion unit performs coordinate conversion on the dq coordinates in the current control unit using the electrical angle of the permanent magnet synchronous machine corrected by the third correction phase that is the sum of the first correction phase and the second correction phase. Thereby, the control device can calculate the correction value of the magnetic pole position with a simple configuration.

1 is a block diagram showing the configuration of a control device according to Embodiment 1; FIG. 4 is a block diagram showing the configuration of a first correction phase calculator according to Embodiment 1; FIG. 4 is a diagram showing the relationship between a coordinate system based on actual magnetic pole positions of the electric motor according to Embodiment 1 and a coordinate system including an error deviation corresponding to the decoupling voltage; FIG. 2 is a diagram showing the hardware configuration of main parts of the control device according to Embodiment 1; FIG. FIG. 4 is a block diagram showing the configuration of a control device according to Embodiment 2; FIG. 8 is a block diagram showing the configuration of an operation mode setting unit according to Embodiment 2; FIG. 9 is a flow chart showing an example of operation in learning operation of the control device according to Embodiment 2; 9 is a flow chart showing an example of operation in learning operation of the control device according to Embodiment 2; 10 is a flow chart showing an example of operation in normal operation of the control device according to Embodiment 3;

A mode for carrying out the present invention will be described with reference to the accompanying drawings. In each figure, the same or corresponding parts are denoted by the same reference numerals, and overlapping descriptions are appropriately simplified or omitted.

Embodiment 1.
FIG. 1 is a block diagram showing the configuration of a control device according to Embodiment 1. FIG.

A control device 1 is a device that drives a permanent magnet synchronous machine. In this example, the permanent magnet synchronous machine is the electric motor 2 . The electric motor 2 is, for example, a three-phase electric motor. In this example, the shape of the rotor of the electric motor 2 is, for example, a non-salient pole shape. The electric motor 2 is applied, for example, to an elevator. The electric motor 2 is applied, for example, to an elevator hoist or a door.

Generally, in the control of a three-phase AC motor, three-phase current and voltage consisting of U-phase, V-phase, and W-phase are often converted into two axes and handled. A coordinate system on stationary two axes in which the U-phase axis of the three phases is aligned with the α-axis is called an α-β coordinate system. A coordinate system on two axes of rotation with the d-axis aligned with the direction of the magnetic field of the rotor is called a dq coordinate system. The electrical angle θ _re of the rotor of the electric motor 2 is the rotation angle of the dq coordinate system viewed from the α-β coordinate system.

The control device 1 includes a current detector 3, a rotation angle detector 4, a phase calculator 5, a speed calculator 6, a current command generator 7, a current controller 8, and a first correction phase calculator 9. , a second correction phase calculator 10 , a coordinate converter 11 , and a power converter 12 .

The current detector 3 is a device that measures the current flowing through the electric motor 2 . The current detector 3 is provided in each phase wiring so as to be able to measure, for example, three phase currents input to the electric motor 2 . In this example, the current detector 3 measures a _U -phase current iU, a _V -phase current iV, and a _W -phase current iW, respectively.

The rotation angle detector 4 is a device that detects the rotation angle of the electric motor 2 . The rotation angle detector 4 includes, for example, an optical encoder, resolver or magnetic sensor.

The phase calculator 5 is a part that calculates the electrical angle θ _re of the rotor of the electric motor 2 . In the calculation of the electrical angle θ _re in the phase calculator 5, for example, the rotation angle of the electric motor 2 detected by the rotation angle detector 4 is used.

The speed calculator 6 is a part that calculates the rotational speed ω of the electric motor 2 . In calculating the rotation speed ω, for example, the time differentiation of the rotation angle of the electric motor 2 detected by the rotation angle detector 4 is used.

The current command generator 7 is a part that generates a d-axis current command value i _d ^* and a q-axis current command value i _q ^* as current command values in the dq coordinate system. In this example, the command value i _d ^* of the d-axis current is set to 0 when the shape of the rotor is non-salient. The q-axis current command value i _q ^* is calculated, for example, by converting the torque command value calculated based on the deviation between the rotation speed command value and the actual value of the electric motor 2 into a current command value. The torque command value is calculated by, for example, P control (P: Proportional), PI control (I: Integral), PID control (D: Differential), or other control methods.

The current control unit 8 is a part that calculates a d-axis voltage command value v _d and a q-axis voltage command value v _q as voltage command values in the dq coordinate system. Calculation of the voltage command value by the current control unit 8 is based on current command values i _d ^* and i _q ^* in the dq coordinate system, actual current values i _d and i _q in the dq coordinate system, and the electric motor 2 , and the rotational speed ω of .

Based on the deviation between the current command values i _d ^* and i _q ^* in the dq coordinate system and the actual current values i _d and i _q in the dq coordinate system, the current control unit 8 performs vector control. Calculates the compensation voltage that causes the actual value to follow the command value. A compensation voltage is calculated by feedback control. The compensation voltage is calculated by P control, PI control, PID control, or other control methods, for example.

Also, voltage interference generally occurs between the d-axis and the q-axis. Therefore, in the current control unit 8, feedforward compensation is performed by a decoupling voltage that decoupling the voltage interference. The decoupling voltage is calculated from the electrical angular velocity of the motor 2, the actual value of the current in the dq coordinate system, and the parameters of the motor 2. FIG. The electrical angular velocity is calculated by multiplying the rotational speed ω of the electric motor 2 calculated by the speed calculating section 6 by the number of pole pairs of the electric motor 2 . Parameters of the electric motor 2 include, for example, inductance and induced voltage constant.

The current control unit 8 outputs the sum of the compensation voltage and the interference voltage obtained as described above as a voltage command value in the dq coordinate system.

The first correction phase calculator 9 is a part that calculates the _first correction phase Δθ1. The second correction phase calculator 10 is a part that calculates the _second correction phase Δθ2. The first correction phase Δθ ₁ and the second correction phase Δθ ₂ are used to correct the electrical angle θ _re calculated by the phase calculator 5 .

The coordinate transformation unit 11 is a part that transforms the dq coordinates in the current control unit 8 based on the corrected electrical angle. The coordinate transformation unit 11 is an example of a transformation unit. The coordinate transformation unit 11 includes a 3-phase/2-axis transformation unit 13 and a 2-axis/3-phase transformation unit 14 . A 3-phase/2-axis converter 13 converts the 3-phase currents i _U , i _V , and i _W of the electric motor 2 detected by the current detector 3 into the 2-axis currents i _d and i _q in the dq coordinate system. This is the part that converts the coordinates to The 2-axis/3-phase conversion unit 14 converts the 2-axis voltage command values v _d and v _q in the dq coordinate system calculated by the current control unit 8 into the 3-phase voltage command values v _U , v _V , and v This is the part for coordinate conversion to _W.

The power converter 12 is a device that converts the voltage of a power supply (not shown) into a voltage of variable voltage and variable frequency based on an input voltage command value. In this example, the power converter 12 includes a converter that converts the AC power source voltage into a DC voltage, and an inverter that converts the DC voltage converted by the converter into a variable voltage variable frequency AC voltage.

Next, an example of electrical angle correction in the control device 1 will be described with reference to FIGS. 2 and 3. FIG.

FIG. 2 is a block diagram showing a configuration of a first correction phase calculator according to Embodiment 1. FIG.

The first correction phase calculator 9 calculates the first correction phase Δθ ₁ based on the command value vd of the _d -axis voltage output by the current controller 8 . The first correction phase calculator 9 has a gain amplifier 15 and an integrator 16 . The gain amplifier 15 multiplies the command value of the d-axis voltage by a constant and outputs the result to the integrator 16 . The integrator 16 integrates the input value and outputs it as the _first correction phase Δθ1.

In this example, the d-axis current command value i _d ^* is set to zero. If the electrical angle θ _re calculated by the phase calculator 5 does not deviate from the actual magnetic pole position of the electric motor 2 and the deviation between the command value and the actual value of the d-axis current is 0 due to current feedback control, the current The control unit 8 calculates the d-axis compensation voltage as 0 in the steady state. On the other hand, when the electrical angle θ _re calculated by the phase calculator 5 deviates from the actual magnetic pole position of the electric motor 2, the q-axis current flows into the d-axis. compensation voltage does not become 0.

The first correction phase calculator 9 uses this characteristic to calculate the _first correction phase Δθ1 until the command value vd of the _d -axis voltage becomes zero. As a result, the first correction phase Δθ ₁ becomes a correction value for correcting the deviation between the electrical angle θ _re calculated by the phase calculator 5 and the actual magnetic pole position of the electric motor 2 .

Here, the command value vd of the _d -axis voltage includes the non-coupling voltage in addition to the compensating voltage. Therefore, the first corrected phase contains an error corresponding to the decoupling voltage. Therefore, the second corrected phase calculator 10 calculates the _second corrected phase Δθ2, which is a correction value for correcting the error corresponding to the non-interfering voltage.

FIG. 3 is a diagram showing the relationship between the coordinate system based on the actual magnetic pole positions of the motor according to Embodiment 1 and the coordinate system including the deviation of the error corresponding to the decoupling voltage.

In FIG. 3, the d-axis and the q-axis represent a dq coordinate system according to the actual magnetic pole positions of the electric motor 2. In FIG. The dc and qc axes represent the dq coordinate system with error shifts corresponding to the decoupling voltages. At this time, there is an angular error of Δθ between the d-axis and the dc-axis and between the q-axis and the qc-axis.

The actual d-axis current and q-axis current in the electric motor 2 are represented by the following equations (1) and (2) using the current value _iqc from the relationship of the coordinate system shown in FIG. Here, the current value _iqc is the current value treated as the actual value of the q-axis current in the control device 1 when there is no correction by the _second correction phase Δθ2. Also, in this example, the d-axis current is controlled to zero.

Also, using equations (1) and (2), the voltages v _d and v _q in the actual dq coordinate system of the electric motor 2 are expressed as the following equations (3) and (4). . Here, R represents a resistance value. Ld and Lq represent the inductance of the _d -axis and _q -axis. φ represents an induced voltage constant. ω _re represents the electrical angular velocity.

Similar to equations (1) and (2), the relationship between the d-axis voltage and q-axis voltage and the dc-axis voltage and qc-axis voltage is derived from the relationship of the coordinate system shown in FIG. At this time, considering equations (3) and (4), the dc-axis voltage is represented by the following equation (5).

Here, since the first term on the right side of Equation (5) is the decoupling voltage on the dc axis, it can be seen that the second and third terms on the right side are the compensation voltages. Since the first correction phase Δθ ₁ is calculated so that the command value vdc of the _dc -axis voltage in the control device 1 becomes 0, the left side of the equation (5) becomes 0 when the correction by the first correction phase Δθ ₁ is considered. Become. At this time, when equation (5) is solved for Δθ, Δθ becomes a function of the inductance of motor 2, the induced voltage constant, and the qc-axis current, as expressed in equation (6).

That is, Δθ1 calculated by the _first correction phase calculator 9 is a value having an error of Equation (6) with respect to the correct correction value for the deviation of the magnetic pole position. In order to correct this error, the second corrected phase calculator 10 calculates the second corrected phase Δθ ₂ as Δθ ₂ =Δθ using equation (6). Therefore, the _third correction phase Δθ3, which is the correction value for the deviation of the magnetic pole position, is obtained by adding the _first correction phase Δθ1 and the _second correction phase Δθ2.

Note that when the current control unit 8 causes the actual value of the q-axis current to follow the command value, the second correction phase calculation unit 10 uses either the command value or the actual value as the q-axis current in equation (6). may be used.

The coordinate conversion unit 11 converts the dq coordinates in the current control unit 8 using the electrical angle corrected by adding the _third correction phase Δθ3 to the electrical angle θ _re calculated by the phase calculation unit 5. do the conversion.

As described above, the control device 1 according to Embodiment 1 includes the current command generation unit 7, the current control unit 8, the first correction phase calculation unit 9, the second correction phase calculation unit 10, the conversion and A current command generator 7 generates command values for the d-axis current and the q-axis current of the permanent magnet synchronous machine. The current control unit 8 receives the command values generated by the current command generation unit 7 and calculates command values for the d-axis voltage and the q-axis voltage of the permanent magnet synchronous machine. The first corrected phase calculator 9 calculates the first corrected phase Δθ ₁ based on the command value vd of the _d -axis voltage calculated by the current controller 8 . The second correction phase calculator 10 calculates at least one of the q-axis current command value _iq ^* calculated by the current controller 8 and the q-axis current actual value _iq of the permanent magnet synchronous machine and parameters of the permanent magnet synchronous machine. A _second correction phase Δθ2 is calculated based on. The conversion unit performs coordinate conversion on the dq coordinates in the current control unit 8 using the electrical angle of the permanent magnet synchronous machine corrected by the _third correction phase Δθ3. The _third corrected phase Δθ3 is the sum of the _first corrected phase Δθ1 and the _second corrected phase Δθ2.

Thereby, the control device 1 does not require additional hardware such as a voltage sensor for correcting the electrical angle. Therefore, the control device 1 can calculate the correction value of the magnetic pole position with a simple configuration.

In general, current control of a motor, which is a permanent magnet synchronous motor, is performed based on current values in a coordinate system on dq axes, which are rotational coordinates. Therefore, the magnetic pole position of the rotor of the motor is important information that serves as a reference for current control. Here, for example, in an electric motor such as an elevator that requires a large torque at a low rotation speed, a multi-pole design with as many as several tens of magnet poles is often adopted. In this case, the deviation of the rotation angle of the electric motor becomes a large deviation when converted to an electrical angle. Therefore, in order to reduce the deviation of the electrical angle, in addition to the detection accuracy of the sensor itself such as the rotation angle detector, the installation accuracy of the sensor is required to be sufficiently high. On the other hand, mounting the equipment so as to limit the deviation of the electrical angle to a few degrees requires mounting accuracy higher than the accuracy of the electrical angle, which leads to an increase in the manufacturing cost of the electric motor.

Therefore, the control device 1 corrects the deviation of the magnetic pole position by the calculated _third correction phase Δθ3. As a result, the electric motor 2 can be prevented from being operated while the magnetic pole positions are shifted. The control device 1 can control the electric motor 2 normally. Therefore, deterioration and destabilization of the control performance due to the deviation of the magnetic pole position can be prevented.

Further, the first correction phase calculator 9 calculates the first correction phase based on the command value vd of the _d -axis voltage, which is the sum of the compensating voltage and the non-interfering voltage. A compensation voltage is calculated based on the deviation between the command value id ^* and the actual value _id of the _d -axis current. The decoupling voltage decoupling voltage interference between the d-axis and the q-axis.

When the electrical angle θ _re calculated by the phase calculator 5 deviates from the actual magnetic pole position of the electric motor 2 , the d-axis compensation voltage does not become 0 even if the d-axis current is controlled to 0. Thus, the d-axis voltage command value reflects the deviation of the magnetic pole position. The command value of the d-axis voltage has the voltage interference decoupled by the decoupling voltage. Therefore, the first corrected phase calculator 9 can calculate the _first corrected phase Δθ1 by making the d-axis voltage independent of the q-axis voltage. At this time, the first corrected phase Δθ ₁ contains an error derived from the decoupling voltage. The _second correction phase Δθ2 corrects the error contained in the _first correction phase Δθ1. Therefore, the control device 1 can calculate the correction value of the deviation of the magnetic pole position in consideration of the compensating voltage and the decoupling voltage.

Further, the first correction phase calculator 9 calculates the _first correction phase Δθ1 by multiplying the command value vd of the _d -axis voltage by a constant and integrating the result.

Thereby, the first correction phase calculator 9 can calculate the _first correction phase Δθ1 by a simple method. Also, the first corrected phase calculator 9 calculates the _first corrected phase Δθ1 from the command value of the d-axis voltage affected by the correction of the electrical angle. As a result, even if there is an error between the design value and the actual value of the power supply voltage, the _first correction phase Δθ1 is calculated so that the d-axis voltage becomes zero.

Further, the second corrected phase calculator 10 calculates the _second corrected phase Δθ2 using the inductance and the induced voltage constant of the permanent magnet synchronous machine as parameters.

Thereby, the second corrected phase calculator 10 can calculate the _second corrected phase Δθ2 based on known values for the permanent magnet synchronous machine.

Note that the current detector 3 may measure only two of the three phase currents. The current detector 3 may be a device that measures the current flowing through the electric motor 2 and is not limited to a device that measures the output current of the power converter 12 . The current detector 3 may estimate the current of each phase by measuring the bus line current of the power converter 12, for example, like a current measurement method using a one-shunt resistor.

Further, the rotation angle detector 4 may be any device that detects the rotation angle of the electric motor 2, and is not limited to an encoder or the like. The rotation angle detector 4 may be equipped with, for example, a function of detecting rotation speed, and may calculate the rotation angle of the electric motor 2 by time integration of the detected rotation speed.

Further, in calculating the rotation speed ω, the speed calculation unit 6 may remove noise due to time differentiation of the rotation angle by, for example, smoothing with a low-pass filter. The speed calculator 6 may calculate the rotational speed of the electric motor 2 at regular intervals. The speed calculator 6 may include means for measuring time. At this time, the speed calculator 6 may calculate the rotation speed for each constant rotation angle.

Also, the current command generator 7 may calculate the q-axis current command value i _q ^* so as to control the rotation angle of the electric motor 2 . For example, when causing the electric motor 2 to output a constant torque, the current command generator 7 may calculate the q-axis current command value i _q ^* by converting the constant torque command value into a current command value. good.

Further, the power converter 12 may be a device that converts the voltage of the power supply into a voltage of a variable voltage and a variable frequency based on the input voltage command value, and is not limited to a device that performs conversion using a converter and an inverter, for example. The power converter 12 may be a device, such as a matrix converter, that directly converts an AC voltage into a variable AC voltage with a variable frequency. The power converter 12 may also comprise means for correcting the dead time of the inverter.

Also, the 2-axis/3-phase converter 14 may be provided in hardware integrated with the power converter 12, for example. That is, the hardware including the power converter 12 and the 2-axis/3-phase conversion unit 14 converts the 3-phase voltages consisting of the U-phase, the V-phase and the W-phase based on the input of the command values of the d-axis voltage and the q-axis voltage. The voltage of the power supply may be converted to a variable voltage variable frequency voltage.

In addition, when setting a value such as a command value for the d-axis current or the d-axis voltage to 0, the control device 1 may set the value to a value that can be regarded as 0.

Next, an example of the hardware configuration of the control device 1 will be described with reference to FIG.
FIG. 4 is a diagram showing the hardware configuration of main parts of the control device according to the first embodiment.

Each function of the control device 1 can be realized by a processing circuit. The processing circuit comprises at least one processor 1b and at least one memory 1c. The processing circuitry may comprise at least one piece of dedicated hardware 1a, together with or as an alternative to processor 1b and memory 1c.

When the processing circuit includes the processor 1b and memory 1c, each function of the control device 1 is implemented by software, firmware, or a combination of software and firmware. At least one of software and firmware is written as a program. The program is stored in memory 1c. The processor 1b realizes each function of the control device 1 by reading and executing the programs stored in the memory 1c.

The processor 1b is also called a CPU (Central Processing Unit), processing device, arithmetic device, microprocessor, microcomputer, or DSP. The memory 1c includes, for example, non-volatile or volatile semiconductor memory such as RAM, ROM, flash memory, EPROM, EEPROM, magnetic disk, flexible disk, optical disk, compact disk, mini disk, DVD, and the like.

If the processing circuit comprises dedicated hardware 1a, the processing circuit may be implemented, for example, in a single circuit, multiple circuits, programmed processors, parallel programmed processors, ASICs, FPGAs, or combinations thereof.

Each function of the control device 1 can be implemented by a processing circuit. Alternatively, each function of the control device 1 can be collectively realized by a processing circuit. A part of each function of the control device 1 may be realized by dedicated hardware 1a, and the other part may be realized by software or firmware. Thus, the processing circuit implements each function of the control device 1 with hardware 1a, software, firmware, or a combination thereof.

Embodiment 2.
In the second embodiment, differences from the example disclosed in the first embodiment will be described in detail. Any feature of the example disclosed in the first embodiment may be employed for features not described in the second embodiment.

FIG. 5 is a block diagram showing the configuration of a control device according to Embodiment 2. As shown in FIG.

In the electric motor 2 , the deviation of the magnetic pole position is uniquely determined by the mounting state of the electric motor 2 and the rotation angle detector 4 . Therefore, if the mounting state of the electric motor ₂ and the rotation angle detector 4 does not change, the control device 1 uses the same values can continue to be used.

The electric motor 2 has a plurality of operation modes. The operation modes of the electric motor 2 include, for example, a normal operation mode and a learning operation mode. The normal operation mode is, for example, an operation mode in which the electric motor 2 that supplies driving force to a device provided with the electric motor 2 is normally operated. The learning operation mode is an operation mode in which learning operation of the electric motor 2 is performed to obtain the _third correction phase Δθ3. Learning operation is performed, for example, when the electric motor 2 is installed. Note that the learning operation may be performed when the rotation angle detector 4 is replaced.

Further, when the power supply to the control device 1 is interrupted and then restarted, the attachment state between the electric motor 2 and the rotation angle detector 4 may change due to maintenance of the electric motor 2 or the like before and after the electric power supply is interrupted. There is a possibility that At this time, whether or not the _third correction phase Δθ3 obtained by learning before the power supply is cut off is a value corresponding to the mounting state of the electric motor 2 and the rotation angle detector 4 after the power supply is cut off. is unknown. Therefore, the learning operation may be performed when power supply to the control device 1 is started.

Here, equations (1) to (6) explained in the first embodiment are equations based on the premise that the electric motor 2 is in a steady state. Therefore, in learning operation, the _third correction phase Δθ3 is calculated when the electric motor 2 is operating at a constant speed and constant torque, or when it can be assumed that the electric motor 2 is operating at a constant speed and constant torque. be. That is, in the learning operation, the current command generator 7 sets the command value i _d ^* of the d-axis current to zero. When calculating the _third correction phase Δθ3, the current command generator 7 sets the command value i Generate _q ^* .

The control device 1 includes an operation mode setting section 17 . The operation mode setting unit 17 is a part that sets the operation mode of the electric motor 2 . The operation mode setting unit 17 has a function of outputting the _third correction phase Δθ3 according to the set operation mode of the electric motor 2 .

FIG. 6 is a block diagram showing the configuration of an operation mode setting unit according to Embodiment 2. FIG.

The operation mode setting unit 17 has a storage unit 18 . The storage unit 18 is a part that stores the _third correction phase Δθ3 obtained in the learning operation. When the operation mode of the electric motor 2 is the normal operation mode, the operation mode setting unit 17 outputs the _third correction phase Δθ3 stored in the storage unit 18 . On the other hand, when the operation mode of the electric motor 2 is the learning operation mode, the first correction phase Δθ1 calculated by the _first correction phase calculation unit 9 and the second correction phase Δθ2 calculated by the _second correction phase calculation unit 10 is output as the _third correction phase Δθ3. For example, the storage unit 18 stores the sum of the _first correction phase Δθ1 and the _second correction phase Δθ2 as the _third correction phase Δθ3 when the operation mode is switched from the learning operation mode.

The electrical angle correction value described in the first embodiment is calculated based on the command value vd of the _d -axis voltage, which is the sum of the compensation voltage and the decoupling voltage. Here, there is a possibility that the command value vd of the _d -axis voltage will take a value close to 0 despite the deviation of the magnetic pole position, depending on the direction and magnitude of the deviation of the magnetic pole position. At this time, the control device 1 may not be able to obtain a correct value as the electrical angle correction value. Therefore, in order to improve the accuracy of the _third correction phase Δθ3 calculated in the learning operation, the control device 1 controls the electric motor 2 as follows, for example, in the learning operation.

7 and 8 are flowcharts showing an example of the operation of the control device according to the second embodiment in learning operation.

FIG. 7 shows an example of the operation of the control device 1 that improves the accuracy of the _third correction phase Δθ3 by changing the rotation speed of the electric motor 2 during learning operation.

In step S71, the control device 1 determines whether the command value vd of the _d -axis voltage is equal to or greater than a preset threshold. The determination is made in the operation mode setting unit 17, for example. Here, the threshold is set based on, for example, possible deviation of the magnetic pole position, the operating speed of the electric motor 2 in the learning operation, or parameters of the electric motor 2 . If the determination result for the _d -axis voltage command value vd is No, the operation of the control device 1 proceeds to step S72. If the determination result is Yes, the operation of the control device 1 proceeds to step S73.

In step S72, the control device 1 changes the rotation speed of the electric motor 2 which is operated at a constant speed. Here, the control device 1 changes the rotation speed of the electric motor 2 according to the current command value generated by the current command generator 7, for example. The current command generation unit 7 generates a q-axis current command value i _q ^* , for example, so that the electric motor 2 is operated at a constant rotation speed different from the currently operated rotation speed. After that, the operation of the control device 1 proceeds to step S71.

In step S73, the operation mode setting unit 17 continues to set the operation mode to the learning operation mode. The control device 1 calculates the _third correction phase Δθ3 in the learning operation. The learning operation is completed, for example, when the calculated _third correction phase Δθ3 stops changing. When the learning operation is completed, the storage unit 18 of the operation mode setting unit 17 stores the calculated _third correction phase Δθ3. After that, the operation of the control device 1 in the learning operation ends.

FIG. 8 shows an example of the operation of the control device 1 that improves the accuracy of the _third correction phase Δθ3 by changing the direction of rotation of the electric motor 2 during learning operation.

In step S81, the control device 1 determines whether the command value vd of the _d -axis voltage is equal to or greater than a preset threshold. The determination is made in the operation mode setting unit 17, for example. Here, the threshold is set based on, for example, possible deviation of the magnetic pole position, the operating speed of the electric motor 2 in the learning operation, or parameters of the electric motor 2 . If the determination result for the _d -axis voltage command value vd is No, the operation of the control device 1 proceeds to step S82. If the determination result is Yes, the operation of the control device 1 proceeds to step S83.

In step S82, the control device 1 changes the rotation direction of the electric motor 2 which is operated at a constant speed. Here, the control device 1 changes the rotation direction of the electric motor 2 according to the current command value generated by the current command generator 7, for example. The current command generation unit 7 generates, for example, a q-axis current command value i _q ^* so that the electric motor 2 is operated in a direction of rotation different from the direction of rotation currently being operated. After that, the operation of the control device 1 proceeds to step S81.

In step S83, the operation mode setting unit 17 continues to set the operation mode to the learning operation mode. The control device 1 calculates the _third correction phase Δθ3 in the learning operation. The learning operation is completed, for example, when the calculated _third correction phase Δθ3 stops changing. When the learning operation is completed, the storage unit 18 of the operation mode setting unit 17 stores the calculated _third correction phase Δθ3. After that, the operation of the control device 1 in the learning operation ends.

As described above, the control device 1 according to Embodiment 2 includes the operation mode setting section 17 . The operation mode setting unit 17 sets the operation mode of the permanent magnet synchronous machine. The operating mode setting unit 17 has a storage unit 18 . The storage unit 18 stores the _third correction phase Δθ3 calculated when the operation mode is the learning operation mode. When the operation mode is the normal operation mode, the conversion unit performs coordinate conversion using the electrical angle corrected by the _third correction phase Δθ3 stored in the storage unit 18 .

As long as the mounting state of the motor 2 and the rotation angle detector 4 remains unchanged, the converter can continue to use the same value already obtained by learning as the _third correction phase Δθ3. Thereby, the control device 1 does not need to calculate the correction value of the deviation of the magnetic pole position each time.

Further, when the operation mode is the learning operation mode, the current command generator 7 sets the command value vd of the _d -axis current to zero. At this time, the current command generator 7 generates a q-axis current command value i _q ^* so that the rotation speed of the permanent magnet synchronous machine is constant.

As a result, the learning operation is performed under the condition that the rotation speed of the electric motor 2 is constant. For this reason, the condition that an error is included in the learning of the correction value of the magnetic pole position is avoided. Therefore, the control device 1 can more stably control the electric motor 2 based on the magnetic pole positions corrected with higher accuracy.

Further, when the operation mode is the learning operation mode and the command value vd of the _d -axis voltage is smaller than a preset threshold value, the current command generator 7 adjusts the rotation speed of the permanent magnet synchronous machine in the learning operation mode. Generate a command value i _q ^* for the q-axis current to change.

By changing the rotation speed, the compensation voltage and the interference voltage that constitute the command value vd of the _d -axis voltage change. This prevents the command value vd of the _d -axis voltage from taking a value close to 0 despite the deviation of the magnetic pole position. Thereby, the correction value of the magnetic pole position is learned with higher accuracy.

Further, when the operation mode is the learning operation mode and the command value vd of the _d -axis voltage is smaller than a preset threshold value, the current command generation unit 7 changes the rotation direction of the permanent magnet synchronous machine in the learning operation mode. Generate a command value i _q ^* for the q-axis current to change.

When a load is connected to the electric motor 2, the magnitude of the current value of the electric motor 2 may depend on the direction of rotation. When the current value of the electric motor 2 changes, the magnitude of the _d -axis voltage command value vd also changes. Therefore, the command value vd of the _d -axis voltage is prevented from taking a value close to 0 despite the deviation of the magnetic pole position. Thereby, the correction value of the magnetic pole position is learned with higher accuracy.

Moreover, the operation mode setting unit 17 sets the operation mode to the learning operation mode when the power supply is started.

As a result, even if the attachment state between the electric motor 2 and the rotation angle detector 4 changes while the power supply is interrupted, the control device 1 can maintain the electric motor 2 and the rotation angle detector 4 by the learning operation. It is possible to obtain a correction value corresponding to the mounting state of

Note that the control device 1 may improve the accuracy of the _third correction phase Δθ3 by changing both the rotation speed and the rotation direction of the electric motor 2 in the learning operation.

Embodiment 3.
Embodiment 3 will describe in detail the differences from the examples disclosed in Embodiments 1 and 2. FIG. For features not described in the second embodiment, any feature of the examples disclosed in the first and second embodiments may be adopted.

There is a possibility that the magnetic pole position will shift during normal operation due to aging of the electric motor 2 or the like. At this time, the control performance of the electric motor 2 by the control device 1 may deteriorate or the electric motor 2 may become unstable. Therefore, the control device 1 determines the displacement of the magnetic pole position by monitoring the value of the q-axis current. Here, the q-axis current is a current value corresponding to the torque of the electric motor 2 . The control device 1 switches the operation mode of the electric motor 2 to the learning operation mode when determining the deviation of the magnetic pole position.

An example of the operation of the control device 1 will be described with reference to FIG.
FIG. 9 is a flow chart showing an example of operations in normal operation of the control device according to the third embodiment.

In step S91, the control device 1 determines whether the value of the q-axis current is equal to or less than a preset threshold. The determination is made in the operation mode setting unit 17, for example. Here, for example, when the operation pattern or load of the electric motor 2 in normal operation is determined, the threshold is set based on the torque required in normal operation estimated in advance. Alternatively, the threshold may be set based on the rated torque of the electric motor 2 . If the determination result for the value of the q-axis current is No, the operation of the control device 1 proceeds to step S92. When the determination result is Yes, the operation mode setting unit 17 continues to set the operation mode to the normal operation mode. After that, the operation of the control device 1 proceeds to step S91 again.

In step S92, the operation mode setting unit 17 switches the operation mode of the electric motor 2 to the learning operation mode. After that, the operation of the control device 1 proceeds to step S91.

As described above, in the control device 1 according to Embodiment 3, when the command value or the actual value of the q-axis current exceeds a preset threshold when the operation mode is the normal operation mode, the operation mode The setting unit 17 sets the operation mode to the learning operation mode.

When there is a deviation in the magnetic pole position, the current controlled to flow along the q-axis also flows into the d-axis. Therefore, the q-axis current required to generate the commanded torque increases. Therefore, by monitoring the q-axis current, it is possible to determine the deviation of the magnetic pole position. When it is determined that the magnetic pole positions have shifted, the operation mode setting unit 17 sets the operation mode to the learning operation mode. As a result, the control device 1 can avoid operating the electric motor 2 while the magnetic pole positions are deviated. The control device 1 can stably drive the electric motor 2 .

Note that the value of the q-axis current may suddenly exceed the threshold regardless of the deviation of the magnetic pole position. Therefore, the operation mode setting unit 17 may set the operation mode to the learning operation mode when the command value or the actual value of the q-axis current exceeds a preset threshold value multiple times. Alternatively, the operation mode setting unit 17 sets the operation mode to the learning operation mode when the command value or the actual value of the q-axis current continuously exceeds a preset threshold value for a predetermined time. good too.

Moreover, the control device 1 may include a notification unit. The notification unit is a part that notifies information such as a warning to a person who manages the electric motor 2, for example. For example, when it is not possible to shift to the learning operation mode due to the state of the load of the electric motor 2 , the notification unit issues a warning to stop the operation of the electric motor 2 .

A control device according to the present invention can be applied to control a permanent magnet synchronous machine.

1 control device 2 electric motor 3 current detector 4 rotation angle detector 5 phase calculator 6 speed calculator 7 current command generator 8 current controller 9 first correction phase calculator 10 second second Correction phase calculator 11 coordinate converter 12 power converter 13 three-phase/two-axis converter 14 two-axis/three-phase converter 15 gain amplifier 16 integrator 17 operation mode setting unit 18 storage unit

Claims (10)

a current command generator that generates command values for the d-axis current and the q-axis current of the permanent magnet synchronous machine;
a current control unit for calculating command values for the d-axis voltage and the q-axis voltage of the permanent magnet synchronous machine based on the command value generated by the current command generation unit;
a first correction phase calculation unit that calculates a first correction phase based on the command value of the d-axis voltage calculated by the current control unit;
A second correction phase for calculating a second correction phase based on at least one of the command value of the q-axis current calculated by the current control unit and the actual value of the q-axis current of the permanent magnet synchronous machine and parameters of the permanent magnet synchronous machine a correction phase calculator;
Transformation for performing coordinate transformation on dq coordinates in the current control unit using the electrical angle of the permanent magnet synchronous machine corrected by a third correction phase that is the sum of the first correction phase and the second correction phase Department and
A control device for a permanent magnet synchronous machine. The first correction phase calculator calculates a compensating voltage calculated based on a deviation between a command value and an actual value of the d-axis current, and a non-interfering voltage for decoupling voltage interference between the d-axis and the q-axis. 2. The controller for a permanent magnet synchronous machine according to claim 1, wherein the first correction phase is calculated based on a command value of the d-axis voltage, which is the sum of . 3. The control device for a permanent magnet synchronous machine according to claim 1, wherein the first correction phase calculator calculates the first correction phase by multiplying the command value of the d-axis voltage by a constant and integrating the result. The permanent magnet synchronous machine according to any one of claims 1 to 3, wherein the second corrected phase calculator calculates the second corrected phase using an inductance and an induced voltage constant of the permanent magnet synchronous machine as the parameters. machine controller. an operation mode setting unit having a storage unit that sets an operation mode of the permanent magnet synchronous machine and stores the third correction phase calculated when the operation mode is the learning operation mode,
When the operation mode is the normal operation mode, the conversion unit performs coordinate conversion using the electrical angle corrected by the third correction phase stored in the storage unit. 5. The control device for a permanent magnet synchronous machine according to any one of items 4 to 5. When the operation mode is the learning operation mode, the current command generator sets the command value of the d-axis current to 0, and the q-axis current so that the rotation speed of the permanent magnet synchronous machine is constant. The control device for a permanent magnet synchronous machine according to claim 5, which generates a command value. The current command generator adjusts the rotation speed of the permanent magnet synchronous machine in the learning operation mode when the command value of the d-axis voltage is smaller than a preset threshold when the operation mode is the learning operation mode. 7. The control device for a permanent magnet synchronous machine according to claim 5, wherein the command value of the q-axis current is generated so as to change. When the operation mode is the learning operation mode and the command value of the d-axis voltage is smaller than a preset threshold value, the current command generation unit changes the rotation direction of the permanent magnet synchronous machine in the learning operation mode. The control device for a permanent magnet synchronous machine according to any one of claims 5 to 7, wherein the command value of the q-axis current is generated so as to change. The operation mode setting unit sets the operation mode to the learning operation mode when the operation mode is the normal operation mode and the command value or the actual value of the q-axis current exceeds a preset threshold value. The control device for a permanent magnet synchronous machine according to any one of claims 5 to 8. The control device for a permanent magnet synchronous machine according to any one of claims 5 to 9, wherein the operation mode setting unit sets the operation mode to the learning operation mode when power supply is started.

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