JP2017221001A - Control apparatus for synchronous motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control apparatus for a synchronous motor which can be surely started in a sensorless manner by determining an initial phase of a rotor.SOLUTION: A control apparatus comprises: a feedback current detection unit (an U-phase current sensor 3u, a W-phase current sensor 3w, a V-phase current calculation part 19 and a feedback current selection part 24) for detecting a current of any one phase, that is selected by a phase selection signal (s), flowing to a PM motor 1 as a feedback current I; a phase voltage command calculation unit (a phase current deviation calculation part 25 and a phase current PI calculation part 26) for calculating a phase voltage command value Vbased on a phase current command value Iand the feedback current I; a three-phase voltage command value calculation unit for calculating a three-phase voltage command value defining the phase that is selected by the phase selection signal (s), as the phase voltage command value V; and an initial phase selection unit 27 for outputting an initial phase θthat is set in accordance with the phase selection signal.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a control device for a synchronous motor.

  A permanent magnet synchronous motor (hereinafter referred to as PM motor) controls rotation by generating torque by passing a current having a phase difference of 90 degrees with respect to the magnetic pole position of the rotor. For this reason, it is necessary to detect the rotor magnetic pole position in order to control the PM motor. However, since a sensor for detecting the rotor magnetic pole position is disadvantageous in terms of installation environment and cost, a sensorless control method for the rotor magnetic pole position has been proposed in recent years.

  When the PM motor rotates at a high speed, the back electromotive force required for the estimation calculation is large and the rotor position estimation calculation is relatively easy, and a sensorless control method with practical accuracy has been established. On the other hand, in sensorless control at a low speed including at the time of start-up, an error in estimation accuracy increases because the back electromotive force is small. In particular, at the time of starting, the PM motor may not be able to start due to insufficient starting torque or out of step due to an error in the rotor position.

  Therefore, a method using an inductance change caused by applying a harmonic has been proposed as a sensorless starting method for a PM motor (for example, Patent Document 1). Further, there is known a synchronous pull-in method in which a suitable d-axis or q-axis current command value is given, a direct current is allowed to flow while starting at zero speed, and the rotor is pulled into a specific position (for example, Patent Document 2). .

JP, 2006-039774, A JP 2008-245411 A

  However, in Patent Document 1, since the difference (saliency) between the d-axis inductance and the q-axis inductance is used, there is a problem that it is difficult to apply unless it is a salient pole type PM motor (IPM motor). Also, in Patent Document 2, it is possible to start with a non-salient PM motor (SPM motor), but current control on the dq coordinate is required, so the effect of phase estimation error is detected by rotational coordinate conversion of the detected current. There was an easy problem.

  The object of the present invention is to solve the above-mentioned problems of the prior art, determine the initial phase of the rotor with high accuracy without being affected by motor parameters and phase estimation errors, and start synchronously without a sensor It is to provide a control device.

The control apparatus for a synchronous motor according to the present invention is a control apparatus for a synchronous motor that controls an inverter circuit that drives the synchronous motor with a three-phase voltage command value, and that is selected by a phase selection signal and flows to the synchronous motor. A feedback current detection unit that detects a current of one phase as a feedback current, a phase voltage command calculation unit that calculates a phase voltage command value based on the phase current command value and the feedback current, and selected by the phase selection signal A three-phase voltage command value calculation unit that calculates the three-phase voltage command value having a phase as the phase voltage command value; and an initial phase selection unit that outputs an initial phase set according to the phase selection signal It is characterized by doing.
Further, in the synchronous motor control device of the present invention, in the starting phase current control by the feedback current detector, the phase voltage command calculator, the three-phase voltage command value calculator, and the initial phase selector, the rotor position After fixing the initial phase to the initial phase, sensorless control of the rotor magnetic pole position may be executed.
Furthermore, in the control apparatus for a synchronous motor according to the present invention, the three-phase voltage command value calculation unit sets the phase not selected by the phase selection signal as a value obtained by −½ the phase voltage command value. The phase voltage command value may be calculated.
Further, in the synchronous motor control device of the present invention, when the direction of the magnetic flux generated when a current is passed through the U-phase winding is used as a reference, the initial phase selection unit selects the U-phase by the phase selection signal. Then, 90 deg is output as the initial phase, 210 deg is output as the initial phase when the V phase is selected by the phase selection signal, and 330 deg is output as the initial phase when the W phase is selected by the phase selection signal. Also good.

  According to the present invention, the rotor position of the PM motor can be fixed at a predetermined position by controlling the current of one phase among the three phases. As a result, since it can be started from a known rotor position, there is an effect that the PM motor can be started reliably and smoothly without installing a rotor position detector.

It is a circuit block diagram which shows the circuit structure of embodiment of the control apparatus of the synchronous motor which concerns on this invention. It is a circuit block diagram which shows the structure of the three-phase voltage command value selection part shown in FIG. It is a figure which shows the conversion table shown in FIG. It is a figure which shows the rotor drawing-in position when the U-phase current is controlled in the starting phase current control. It is a figure which shows the rotor drawing-in position when controlling the V-phase current in the starting phase current control. It is a figure which shows the rotor drawing-in position when the W phase current is controlled in the starting phase current control.

Next, embodiments of the present invention will be specifically described with reference to the drawings.
The present embodiment is a control device that drives and controls a permanent magnet type synchronous motor (hereinafter referred to as PM motor 1) as a synchronous motor. Referring to FIG. 1, an inverter circuit 2 and U-phase current sensors 3u, W A phase current sensor 3w and a control unit 10 are provided. The power source is a DC power source using three-phase AC + diode rectification, and a DC voltage V _{dc obtained} by rectifying the three-phase AC power source 5 by a diode bridge circuit 6 and removing ripples by a smoothing capacitor 7 is supplied to the inverter circuit 2. The circuit 2 is configured to output a variable voltage and variable frequency three-phase alternating current and apply it to the PM motor 1.

  The inverter circuit 2 is composed of switch elements Q1 to Q6 that are bridge-connected. As the switch elements Q1 to Q6, an NPN bipolar transistor or an FET (Field Effect Transistor) can be used, and an IGBT (Insulated Gate Bipolar Transistor) or a thyristor can be used instead of the transistor.

  The U-phase current sensor 3u detects the current value of the current flowing in the U-phase winding of the PM motor 1, and the W-phase current sensor 3w detects the current value of the current flowing in the W-phase winding of the PM motor 1, respectively. It is a detection means. As the U-phase current sensor 3u and the W-phase current sensor 3w, a current sensor constituted by a coil and a Hall element or a shunt resistor can be used.

The control unit 10 generates and generates U-phase, V-phase, and W-phase three-phase voltage command values V _u ^* , V _v ^* , and V _w ^* based on vector control with the speed command value ω _m ^* as a target. The voltage command value supply means supplies the three-phase voltage command values V _u ^* , V _v ^* , and V _w ^* to the inverter circuit 2. It should be noted that each function of the control unit 10 described below includes a computer configured by a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like, a program stored in the ROM, the RAM, and the like. It is realized by.

  The control unit 10 includes a d-axis current deviation calculation unit 11, a d-axis current PI calculation unit 12, a speed deviation calculation unit 13, a speed PI calculation unit 14, a q-axis current deviation calculation unit 15, and a q-axis current PI. Calculation unit 16, dq axis / 2 phase coordinate conversion unit 17, three phase voltage command value selection unit 18, V phase current calculation unit 19, three phase / 2 phase coordinate conversion unit 20, two phase / dq axis Coordinate converter 21, rotor position estimator 22, PWM gate signal generator 23, feedback current selector 24, phase current deviation calculator 25, phase current PI calculator 26, and initial phase selector 27 And.

  When the PM motor 1 is started, the control unit 10 includes a three-phase voltage command value selection unit 18, a PWM gate signal generator 23, a feedback current selection unit 24, a phase current deviation calculation unit 25, and a phase current PI calculation unit. 26 and the initial phase selection unit 27 are operated to start phase current control so that the rotor position of the PM motor 1 is fixed at a predetermined position and started from a known rotor position.

d-axis current deviation calculation unit 11, the d-axis current setting value I _d ^* that is set by the user, the difference between the d-axis current value I _d outputted from the 2-phase / dq axis coordinate converting unit 21 d-axis current It is a subtractor that calculates as a deviation.

The d-axis current PI calculation unit 12 performs PI calculation (proportional integration calculation) on the d-axis current deviation calculated by the d-axis current deviation calculation unit 11 and outputs the d-axis output from the two-phase / dq-axis coordinate conversion unit 21. current value I _d is, calculates a d-axis voltage command value V _d ^* which instructs the voltage so as to match the d-axis current setting value I _d ^*.

The speed deviation calculation unit 13 is a subtractor that calculates the difference between the motor speed command value ω _m ^* supplied from the outside and the speed estimation value ω _m estimated by the rotor position estimation unit 22 as a motor speed deviation. .

The PI calculation (proportional integration calculation) is performed on the motor speed deviation calculated by the speed PI calculation unit 14 and the speed deviation calculation unit 13, and the q-axis current command value _Iq ^* is calculated and obtained by performing gain adjustment. The q-axis current command value I _q ^* is output to the q-axis current deviation calculation unit 15.

q-axis current deviation calculation unit 15, q axis current conversion gain adjustment q-axis current command value output from unit 16 I _q ^*, 2-phase / output from the dq-axis coordinate converting unit 20 q-axis current value I _q It is a subtractor which calculates the difference with q-axis current deviation.

The q-axis current PI calculation unit 16 performs PI calculation (proportional integration calculation) on the q-axis current deviation calculated by the q-axis current deviation calculation unit 15, and outputs the q-axis output from the two-phase / dq-axis coordinate conversion unit 21. current value I _q is, calculates the q-axis voltage command value V _q ^* which instructs the voltage to conform to the q-axis current conversion gain adjusting unit 16 q-axis current command value output from the I _q ^*.

The dq-axis / 2-phase coordinate conversion unit 17 includes a d-axis voltage command V _d ^* calculated by the d-axis current PI calculation unit 12 and a q-axis voltage command value V _q ^* calculated by the q-axis current PI calculation unit 16 ^. Are converted into two-phase voltage command values V _α ^* and V _β ^* on the α axis and β axis based on the phase angle θ _e estimated by the rotor position estimating unit 22.

  As shown in FIG. 2, the three-phase voltage command value selection unit 18 includes a conversion table 181, a three-phase voltage command value calculation unit 182, a two-phase / three-phase coordinate conversion unit 183, and a selection switch 184.

Referring to FIG. 3, the conversion table 181 includes a phase voltage command value V * output from the phase current PI calculation unit 26 and a phase selection signal s for selecting any one of the U phase, the V phase, and the W phase. Corresponding three-phase voltage command values V _u ^* , V _v ^* , and V _w ^* are set. The phase selection signal s has a function of selecting the starting phase current control and the sensorless control of the rotor magnetic pole position, which is normal rotation control, and selects the phase for controlling the current in the starting phase current control. It has the function to do. In the present embodiment, the phase selection signal s changes in a value from “0 to 3”, and when the phase selection signal s is set to “0”, normal rotation control is executed, and the phase selection signal s is When the value is set to any one of “1 to 3”, the starting phase current control is executed. When the phase selection signal s is set to “1”, the starting phase current control is executed with the current of the U phase, and when the phase selection signal s is set to “2”, the start with the current of the V phase is started. When the time phase current control is executed and the phase selection signal s is set to “3”, the start time phase current control is executed with the W phase current.

The three-phase voltage command value calculation unit 182 uses the conversion table 181 to select the phase voltage command value V ^* output from the phase current PI calculation unit 26 and any of the U phase, the V phase, and the W phase. Based on the phase selection signal s, the U-phase voltage command value V _u ^* , the V-phase voltage command value V _v ^* , and the W-phase voltage command value V _w ^* are calculated.

The two-phase / three-phase coordinate conversion unit 183 is based on the _α- phase and β-axis two-phase voltage command values V _α ^* and V _β ^* converted by the dq-axis / two-phase coordinate conversion unit 17, and the U-phase voltage. The command value V _u ^* , the V-phase voltage command value V _v ^* , and the W-phase voltage command value V _w ^* are calculated, and the obtained U-phase voltage command value V _u ^* and V-phase voltage command value V _{v are obtained.} ^* Outputs the W-phase voltage command value _Vw ^* .

  When the phase selection signal s is set to one of “1 to 3”, the selection switch 184 sets the U-phase voltage command value Vu * and V-phase output from the three-phase voltage command value calculation unit 182. When the voltage command value Vv * and the W-phase voltage command value Vw * are output to the PWM gate signal generator 23 and the phase selection signal s is set to “0”, it is output from the 2-phase / 3-phase coordinate conversion unit 183. The U-phase voltage command value Vu *, the V-phase voltage command value Vv *, and the W-phase voltage command value Vw * are output to the PWM gate signal generator 23. The phase selection signal s is input to the feedback current selection unit 24 and the initial phase selection unit 27 together with the three-phase voltage command value selection unit 18 in the starting phase current control.

The V-phase current calculation unit 19 performs the U-phase current value I _u obtained by the U-phase current sensor 3u and the W-phase current value I _w obtained by the W-phase current sensor 3w under a three-phase equilibrium condition. based on the bets, a subtractor for calculating a current value I _v of the V-phase.

The three-phase / two-phase coordinate conversion unit 20 includes a U-phase current value I _u detected by the U-phase current sensor 3u, a W-phase current value I _w detected by the W-phase current sensor 3w, and a V-phase current. The V-phase current value I _v obtained by the calculation unit 19 is converted into two-phase voltage command values V _α and V _β on the α-axis and β-axis.

The two-phase / dq-axis coordinate conversion unit 21 uses the two-phase voltage command values V _α and V _β converted by the three-phase / two-phase coordinate conversion unit 20 to calculate the electrical angle θ _e obtained by the rotor position estimation unit 22. The d-axis current value obtained by converting the d-axis current value I _d on the d-axis and the q-axis current value I _q on the q-axis of the rotating coordinate system that rotates in synchronization with the rotor of the PM motor 1 based on I _d is output to the d-axis current deviation calculation unit 11, and the obtained q-axis current value I _q is output to the q-axis current deviation calculation unit 15.

The rotor position estimator 22 includes the two-phase voltage command values V _α ^* and V _β ^* output from the dq axis / 2-phase coordinate converter 17 and the two-phase output from the three-phase / 2-phase coordinate converter 20. A speed estimation value ω _m is generated based on the currents i _α and i _β, and the generated speed estimation value ω _m is output to the speed deviation calculation unit 13. Further, the rotor position estimation unit 22 and the rotor position estimation unit 22 include the generated speed estimation value ω _m , the d-axis current setting value I _d ^*, and the q-axis calculated by the speed PI calculation unit 14. The electrical angle θ _e is generated based on the current command value I _q ^*, and the generated electrical angle θ _e is output to the dq axis / two-phase coordinate conversion unit 17 and the two-phase / dq axis coordinate conversion unit 21. The electrical angle θ _e represents the rotation angle between the reference axis and the rotor axis of the rotor, with the stator winding axis, for example, the U-phase winding axis as the reference axis. The estimated speed value ω _m is an estimated rotational angular speed of the rotational axis of the PM motor 1.

The PWM gate signal generator 23 converts the U-phase voltage command value V _u ^* , the V-phase voltage command value V _v ^* , and the W-phase voltage command value V _w ^* output from the three-phase voltage command value selector 18. Based on this, an inverter gate signal for turning on / off the switching elements Q1 to Q6 of the inverter circuit 2 is generated, and the inverter circuit 2 is driven.

When the phase selection signal s is set to any one of “1 to 3”, the feedback current selection unit 24 selects the U-phase current obtained by the U-phase current sensor 3u selected by the phase selection signal s. and values I _u, the current value I _w of W-phase current sensor 3w Thus the obtained W-phase, one of the current value I _v of the V-phase calculated by the V-phase current computing unit 19 as a feedback current I _fb The set feedback current I _fb is output to the phase current deviation calculator 25. When the phase selection signal s is set to “1”, the current value I _u of the U phase is set to “1”, and when the phase selection signal s is set to “2”, the current value I _v of the V phase is set to the phase selection signal s. Is set to “3”, the W-phase current value _Iw is selected. In the starting phase current control, control is performed so that a direct current flows through the current of one phase selected by the phase selection signal s. In general, a general-purpose inverter has two phases of output current sensors (U-phase current sensor 3u and W-phase current sensor 3w), and therefore the phase to which the current sensor is attached by the phase selection signal s (U-phase and W-phase). It is desirable to control the phase current, but it is possible to calculate the current of the remaining phase (W phase) under the three-phase equilibrium condition, so any one of the three phases can be selected. I do not care.

The phase current deviation calculation unit 25 is a subtractor that calculates a difference between the set phase current command value I ^* and the feedback current _Ifb as a phase current deviation. The phase current command value I ^* can be arbitrarily set as long as it is within the rated current range of the PM motor 1. In particular, when starting torque is required with a large inertia, a large starting torque can be obtained by setting the phase current command value I ^* to the limit of the rated current.

The phase current PI calculation unit 26 calculates the phase voltage command value V ^* by performing PI calculation (proportional integration calculation) on the phase current deviation calculated by the phase current deviation, and calculates the calculated phase voltage command value V ^* to 3 This is output to the three-phase voltage command value calculator 182 of the phase voltage command value selector 18.

The initial phase selection unit 27 outputs the initial phase θ ₀ set according to the phase selection signal s to the rotor position estimation unit 22.

Next, the starting phase current control by the control unit 10 will be described with reference to FIGS.
At the start of the PM motor 1, the phase selection signal s is set to one of the values “1 to 3”, and the phase current command value I ^* is input to the control unit 10. The starting phase current control is executed based on s and the phase current command value I ^*, and the rotor position of the PM motor 1 is fixed at a predetermined position. A common value may be used for the phase current command value I ^* and the d-axis current set value I _d ^* . The duration of the starting phase current control by the control unit 10 is set to be longer than the time required until the rotor position of the PM motor 1 is fixed at a predetermined position. For example, when the inertia is large, it may take time until the rotor position is fixed at a predetermined position. However, it is possible to cope with a motor having a large inertia by setting a long duration of the starting phase current control. .

When the phase selection signal s is set to any value between “1” to “3”, the selection switch 184 causes the U-phase voltage command value V _u ^* and V-phase output from the three-phase voltage command value calculation unit 182. Voltage command value V _v ^* and W phase voltage command value V _w ^* are output to the PWM gate signal generator 23.

The three-phase voltage command value calculation unit 182 uses the conversion table 181 shown in FIG. 3 as the phase voltage command value V ^* for the phase voltage command value selected by the phase selection signal s, and is selected by the phase selection signal s. The voltage command value of the phase that did not exist is set to a value obtained by minus the phase voltage command value V ^* by -1/2.

Thus, the current I corresponding to the phase voltage command value V ^* is set to the phase selected by the phase selection signal s, and the phase voltage command value V ^{* is set} to −1/2 for the phase not selected by the phase selection signal s. A current -I / 2 corresponding to the measured value flows.

FIG. 4 shows the current flowing through the PM motor 1 by the starting phase current control when the phase selection signal s is set to “1” and the U phase is selected. When U-phase is selected by the phase selection signal s, the U-phase winding, the current I corresponding to the phase voltage command value V ^* is, V-phase, and the W-phase phase voltage command value V ^* -1 / A current −I / 2 corresponding to the two values flows. Thereby, magnetic flux is generated in the direction indicated by the arrow in FIG. In general, the direction of the magnetic flux generated when a current is passed through the U-phase winding is defined as 0 deg. Therefore, the rotor position of the PM motor 1 is fixed at 90 deg when the U phase is selected by the phase selection signal s.

FIG. 5 shows a current that flows to the PM motor 1 in the starting phase current control when the phase selection signal s is set to “2” and the V phase is selected. When the V phase is selected by the phase selection signal s, the V-phase winding, the current I corresponding to the phase voltage command value V ^* is, U-phase, the W-phase phase voltage command value V ^* -1 / A current −I / 2 corresponding to the two values flows. Thereby, magnetic flux is generated in the direction indicated by the arrow in FIG. Therefore, the rotor position of the PM motor 1 is fixed at 210 deg when the V phase is selected by the phase selection signal s.

FIG. 6 shows the current that flows to the PM motor 1 by the starting phase current control when the phase selection signal s is set to “3” and the W phase is selected. When W-phase is selected by the phase selection signal s, the W-phase winding, the current I corresponding to the phase voltage command value V ^* is, U-phase, the V-phase phase voltage command value V ^* -1 / A current −I / 2 corresponding to the two values flows. Thereby, a magnetic flux is generated in the direction indicated by the arrow in FIG. Therefore, the rotor position of the PM motor 1 is fixed at 330 deg when the W phase is selected by the phase selection signal s.

In the initial phase selection unit 27, 90 deg, 210 deg, and 330 deg are set as initial phases θ ₀ corresponding to the U phase, the V phase, and the W phase, respectively. Then, the initial phase selecting section 27, the U-phase is selected by the phase selection signal s, the 90deg as the initial phase theta _0, the V phase is selected by the phase selection signal s, the 210deg as the initial phase theta ₀ When the W phase is selected by the phase selection signal s, 330 deg is output to the rotor position estimation unit 22 as the initial phase θ ₀ .

Thereafter, when the phase selection signal s is set to “0”, the selection switch 184 of the three-phase voltage command value selection unit 18 causes the U-phase voltage command value Vu output from the two-phase / three-phase coordinate conversion unit 183. * The V-phase voltage command value Vv * and the W-phase voltage command value Vw * are output to the PWM gate signal generator 23. As a result, normal rotation control based on the input speed command value ω _m ^* and the d-axis current set value I _d ^* is performed with the state where the rotor position is fixed at a predetermined position as the initial phase θ _0. Sensorless control of the rotor magnetic pole position is started.

  In addition, the switching from the starting phase current control to the normal rotation control is performed by setting a duration for continuing the starting phase current control in the control unit 10 and a timing at which the duration set in the control unit 10 has elapsed. Or may be performed at a timing based on an external signal other than the phase selection signal s.

As described above, according to the present embodiment, the control of the synchronous motor that controls the inverter circuit 2 that drives the PM motor 1 that is a synchronous motor with the three-phase voltage command values V _u ^* , V _v ^* , and V _w ^*. a section 10, is selected in a phase selection signal s, the feedback current detecting section for detecting a current of any one phase flowing to the PM motor 1 as a feedback current I _fb (U-phase current sensor 3u, W-phase current sensor 3w , V-phase current calculation unit 19, feedback current selection unit 24), and phase voltage command calculation unit (phase current deviation calculation ⁾ that calculates phase voltage command value V ^* based on phase current command value I ^* and feedback current _Ifb Unit 25, phase current PI calculation unit 26), and a three-phase voltage command value V _u ^* , V _v ^* , V _w ^* with the phase selected by the phase selection signal s as the phase voltage command value V ^* 3 Phase voltage command value display An arithmetic unit 182 and an initial phase selection unit 27 that outputs an initial phase θ ₀ set according to the phase selection signal are provided.

Furthermore, according to the present embodiment, after the rotor position is fixed to the initial phase θ ₀ by the starting phase current control, the sensorless control of the rotor magnetic pole position is executed.

Furthermore, according to the present embodiment, in the starting phase current control, the three-phase voltage command value calculation unit 182 sets the phase voltage command value V ^* to −1/2 for the phases not selected by the phase selection signal s. The three-phase voltage command values V _u ^* , V _v ^* , and V _w ^* are calculated as the calculated values.

Furthermore, according to the present embodiment, when the direction of the magnetic flux generated when a current is passed through the U-phase winding is used as a reference, the initial phase selection unit 27 selects the U-phase by the phase selection signal s. the 90deg as the initial phase theta _0, the 210deg the V phase is selected by the phase selection signal s as the initial phase theta _0, and outputs the 330deg the W phase is selected by the phase selection signal s as the initial phase theta ₀ .

  With these configurations, the rotor position of the PM motor 1 can be fixed at a predetermined position by controlling the current of one phase among the three phases. As a result, since it can be started from a known rotor position, the PM motor 1 can be started reliably and smoothly without installing a rotor position detector. Further, since the phase current is directly controlled, there is a feature that the phase current is not affected by the error of the motor parameter or the estimated phase.

  As mentioned above, although this invention was demonstrated by specific embodiment, the said embodiment is an example and it cannot be overemphasized that it can change and implement in the range which does not deviate from the meaning of this invention.

DESCRIPTION OF SYMBOLS 1 PM motor 2 Inverter circuit 3u U-phase current sensor 3w W-phase current sensor 5 3-phase alternating current power supply 6 Diode bridge circuit 7 Smoothing capacitor 10 Control part 11 d-axis current deviation calculating part 12 d-axis current PI calculating part 13 Speed deviation calculating part 14 speed PI calculation unit 15 q-axis current deviation calculation unit 16 q-axis current PI calculation unit 17 dq-axis / 2-phase coordinate conversion unit 18 3-phase voltage command value selection unit 19 V-phase current calculation unit 20 3-phase / 2-phase coordinate conversion Unit 21 2-phase / dq-axis coordinate conversion unit 22 rotor position estimation unit 23 PWM gate signal generator 24 feedback current selection unit 25 phase current deviation calculation unit 26 phase current PI calculation unit 27 initial phase selection unit 181 conversion table 182 3 phase Voltage command value calculation unit 183 2-phase / 3-phase coordinate conversion unit 184 selection switch

Claims (4)

A control device for a synchronous motor that controls an inverter circuit that drives the synchronous motor with a three-phase voltage command value,
A feedback current detection unit that detects any one-phase current flowing through the synchronous motor selected by a phase selection signal as a feedback current;
A phase voltage command calculator that calculates a phase voltage command value based on the phase current command value and the feedback current;
A three-phase voltage command value calculation unit for calculating the three-phase voltage command value using the phase selected by the phase selection signal as the phase voltage command value;
An apparatus for controlling a synchronous motor, comprising: an initial phase selection unit that outputs an initial phase set in accordance with the phase selection signal.   After fixing the rotor position to the initial phase in the starting phase current control by the feedback current detection unit, the phase voltage command calculation unit, the three-phase voltage command value calculation unit, and the initial phase selection unit, the rotor magnetic pole A control device for a synchronous motor, which performs positionless sensorless control.   The three-phase voltage command value calculation unit calculates the three-phase voltage command value by setting a phase that has not been selected by the phase selection signal to a value that is a half of the phase voltage command value. The synchronous motor control device according to claim 1 or 2.   When the direction of the magnetic flux generated when a current is passed through the U-phase winding is used as a reference, the initial phase selection unit sets 90 deg as the initial phase when the U phase is selected by the phase selection signal. 4. The synchronous motor according to claim 3, wherein when the V phase is selected by a signal, 210 deg is output as the initial phase, and when the W phase is selected by the phase selection signal, 330 deg is output as the initial phase. Control device.

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