JP2008148437A - Controller for permanent magnet type synchronous motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for a permanent magnet type synchronous motor which can smoothly switch V/f-control and sensorless vector control. <P>SOLUTION: In operation for V/f-control, the control is performed on the basis of a δ-γ coordinate representing a coordinate of an inverter without information about the position and the speed of a rotor. On the other hand, in sensorless vector control, the position and the speed of the rotor are estimated for control on the basis of a d-q coordinate representing a coordinate of the rotor. Accordingly, when switching occurs between two types of control, it is necessary to convert the coordinate for control. In the figure, a motor voltage is v, a motor current is i, and a phase difference between the coordinate (δ-γ) at V/f-control and the coordinate (d-q coordinate) at sensorless vector control is θ. Since a δ-axis current is basically controlled to be 0 at V/f-control, the motor current i becomes roughly equal to the γ-axis current. For the magnitude of the phase difference, it is allowed to use values preset a table or those available through functions. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a permanent magnet type synchronous motor, and more particularly to a control device for a permanent magnet type synchronous motor in consideration of a case where there is a periodic load fluctuation.

  Conventionally, in the control of a permanent magnet type synchronous motor, there are two types of control: a sensorless control in the low speed mode and a V / f control in the high speed mode. In such control, for example, there is disclosed one having compensation means for compensating the voltage command and the current command so that the voltage and current applied to the motor do not change suddenly when switching from the high speed mode to the low speed mode (for example, Patent Document 1).

JP 2003-219698 A

  However, in the above-described conventional control, it is necessary to gradually change both the voltage command and the current command before and after the switching of the control, which makes the control complicated and places a burden on the arithmetic unit. Also, for a load with torque pulsation (for example, a single rotary compressor), the relationship with the torque pulsation is not taken into consideration, and when the control method is switched with a large phase of pulsation, In addition, the current may change suddenly, and smooth switching may not be possible.

  The present invention has been made in view of the above, and a first object of the present invention is to provide a control device for a permanent magnet type synchronous motor that can smoothly switch a control method even with a simple configuration. A second object of the present invention is to provide a control device for the permanent magnet type synchronous motor devised in consideration of the case where there is a load with torque pulsation.

  In order to solve the above-described problems and achieve the object, a control device for a permanent magnet type synchronous motor according to the present invention operates an inverter using a voltage command proportional to a speed command, outputs an output voltage phase angle, and a desired value. From the calculation of V / f control that converts the current applied to the motor using the power factor angle of the three-phase / two-phase and feeds it back to the speed command, the voltage command, and the motor applied current to be fed back, the motor The rotor position is estimated, and the motor is controlled by switching between a predetermined calculation from the estimated speed or a calculation of sensorless vector control that is controlled using a current command that is a minimum current by selection from the table. An arithmetic device is provided.

  According to the present invention, the V / f control and the sensorless control basically have no difference in the operation state of the motor, and the drive control can be smoothly switched.

  The permanent magnet synchronous motor control device according to the present invention includes an inverter coordinate system in the permanent magnet synchronous motor control device when switching from the V / f control calculation to the sensorless vector control calculation. The phase difference from the rotor coordinate system of the motor is corrected.

  According to the present invention, since it is not necessary to gradually change the motor current command and the motor voltage command to suppress sudden changes in voltage and current, the control algorithm can be simplified and the burden on the arithmetic processing is small.

  The permanent magnet type synchronous motor control device according to the present invention includes an inverter coordinate system in the permanent magnet type synchronous motor control device when switching from the calculation of the sensorless vector control to the calculation of the V / f control. The phase difference from the rotor coordinate system of the motor and the power factor control angle are corrected.

  According to the present invention, since it is not necessary to gradually change the motor current command and the motor voltage command to suppress sudden changes in voltage and current, the control algorithm can be simplified and the burden on the arithmetic processing is small.

  The permanent magnet type synchronous motor control device according to the present invention is the permanent magnet type synchronous motor control device, wherein the V / f control calculation and the sensorless vector control are performed when the current in the excitation direction is a predetermined value or more. The operation is not switched.

  According to the present invention, when the frequency command is large and so-called field weakening control is performed to increase the torque, the current in the excitation direction increases. In such a case, switching is not performed to prevent the control from becoming unstable due to excessive current.

  In the permanent magnet type synchronous motor control device according to the present invention, in the case of a load having a constant phase pulsating torque, the calculation of the V / f control and the sensorless vector control are performed. The phase for switching between calculation is fixed to a predetermined phase from which the pulsation peak is removed.

  According to the present invention, when there is a sudden change in the motor current waveform due to torque pulsation (variation), and it is known that the change occurs at a constant phase, control is performed using a predetermined position from which the point is removed as a trigger. Since the calculation is switched, an emergency stop due to an overcurrent can be avoided.

  The permanent magnet type synchronous motor control apparatus according to the present invention includes a V / f drive control (δ-γ coordinate axis) and a sensorless vector drive control (d -Q coordinate axis) can be switched smoothly with a simple configuration, and the failure can be suppressed. In addition, there is an effect that smooth switching can be performed even for a load having a constant phase pulsating torque.

  Embodiments of a permanent magnet type synchronous motor control apparatus according to the present invention will be described below in detail with reference to the drawings. In the following description, as is well known to those skilled in the art, the δ-γ coordinate means a rectangular coordinate in the inverter between the δ axis that is the excitation direction and the γ axis that is advanced by 90 degrees in electrical angle. The dq coordinate means a right angle coordinate with the d axis as the field direction of the motor rotor and the q axis with the electrical angle advanced by 90 degrees.

[V / f control calculation]
FIG. 1 is a block diagram showing a calculation process of V / f control performed by the controller for a permanent magnet type synchronous motor according to the present invention. In the figure, ω _m is the rotation speed command, n is the number of pole pairs of the motor, ω ₁ is the inverter output frequency (primary frequency), vδ ^* and vγ ^* are the δ-axis and γ-axis voltage commands, v _u ^* and v, respectively. _v ^*, _{v w} ^* each of the u-phase, v-phase voltage command of the _{w-phase, v u, v v, v} w each u-phase, v-phase, output voltage of the _{w-phase, i u, i v, i} w Are the u-phase, v-phase, and w-phase output currents, iδ, iγ are the δ-axis and γ-axis inverter output currents, θ is the output voltage phase, and φ is the power factor angle.

The V / f control is control in which voltage commands v ^* δ and v ^* γ of voltages supplied to the permanent magnet type synchronous motor 4 are proportional to the speed command ω _f ^* .

The calculation performed by the control device for the permanent magnet type synchronous motor according to the present invention is based on the speed command nω _m by the speed command calculation means (not shown). The speed command instructs to increase or decrease the speed according to the load state. For example, when a permanent magnet type synchronous motor is applied to a compressor used in an air conditioner or the like, the compressor is operated by increasing or decreasing the speed command nω _m when increasing or decreasing the circulation amount of the refrigerant in order to increase or decrease the temperature such as room temperature. Increase or decrease the number of revolutions. Note that ω _m is a rotational speed command (mechanical angle), nω _m is a speed command (electrical angle), and there is a relationship of speed command = n × rotational speed command.

  The calculation performed by the present control device for the permanent magnet type synchronous motor 4 includes voltage command calculation means 1, 2 phase / 3 phase conversion means 2, inverter 3, 3 phase / 2 phase conversion means 5, power factor angle calculation means 6. , Gain 7 and integrator 8. Here, for simplicity, the inverter 3 includes a PWM circuit. The motor 4 is finally driven by the voltage applied from the inverter 3 as a power regulator.

The calculation of the V / f control used in the present invention is characterized by the voltage command calculation means 1, the power factor angle calculation means 6, and the three-phase / two-phase conversion means 5 based on the V / f control that is generally performed. Have The inverter 3 and the integrator 8 may be anything that is generally used for motor control. That is, the inverter 3 only needs to convert power in accordance with the voltage commands v ^* δ and v ^* γ and apply a desired voltage to the motor 4. The integrator 8 only needs to integrate the speed command (angular frequency command) ω ₁ to derive the angle ψ.

In the voltage command calculation means 1, as is generally done, after the u, v, w3 phase currents i _u , i _v , i _w calculated from the output voltage of the inverter 3 are converted into three phases / 2 phases. Δ-axis current iδ, γ-axis current iγ, inverter output frequency ω ₁ , proportional constant K, d-axis induced voltage coefficient Λ _d , and proportional gain Kδ using the following equations (1-1) and (1-2) The δ-axis voltage command vδ ^* and the γ-axis voltage command vγ ^* are obtained by the above calculation.

Specifically, in the calculation of Expression (1-1), the δ-axis voltage command performs negative proportional control so that the δ-axis current iδ becomes zero. Thus, if there is a positive or negative fluctuation of i δ, the voltage command v δ * is determined so as to quickly eliminate the fluctuation of i δ by the gain Kδ. The γ-axis voltage command vγ ^* is set to a voltage value that compensates for the voltage of Λ _d ω ₁ corresponding to the induced voltage, and in order to calculate δ-axis current iδ to 0, iδ is integrated here. Perform integration control. That is, in the calculation of Expression (1-2), if the δ-axis current iδ accumulates with either positive or negative values, a voltage value that returns to the original value by a correspondingly large value is determined. Although integral control is used here, proportional control, proportional + integral control, or the like may be used depending on control responsiveness.

  In this way, when the motor inductance has no anisotropy, iδ becomes 0, and when iδ becomes 0, vδ also becomes 0. Eventually, the current passed through the motor 4 and the motor applied voltage are only the γ-axis component, and the phase coincides, so that the power factor is 1.

  However, since the reluctance torque can be used in the permanent magnet type synchronous motor, the current can be minimized by using both the magnet torque and the reluctance torque in a balanced manner. Therefore, the inventor has found out actively using the power factor angle φ when the δ-axis current and the γ-axis current flow in order to use both the magnet torque and the reluctance torque in a well-balanced manner. Specifically, it was found that the δ-axis current and the γ-axis current power factor angle φ can be defined using the δ-axis current, the γ-axis current combined absolute value I, and the q-axis inductance (for details, see See application 2004-366837).

  As described above, the inventor has found that the control of the minimum current required for generating the torque can be realized by positively controlling the power factor angle (phase difference) instead of φ = 0. Therefore, in the present invention, as shown in FIG. 1, power factor angle calculation means 6 is used which sets θ-φ instead of θ as the rotation axis used when three-phase to two-phase conversion of the motor terminal current is performed. . Since φ is a function of the current I, as shown in the figure, first, I is obtained using the fed back δ-axis and γ-axis currents. If I is obtained, φ is obtained by multiplying it by the above constant. As a result, φ is subtracted from the rotation axis θ of the three-phase / two-phase conversion.

Then, the current subjected to the three-phase / two-phase conversion with θ−φ as the rotation axis is negatively fed back to the speed command nω ^* which is a frequency multiplied by the gain Kω7, and matches the power factor angle φ of the motor which becomes the minimum current. The command nω ^* is corrected as follows. This is because the load increases and the current increases when the position of the rotor of the motor is delayed with respect to the rotating magnetic field, while the load decreases, and the current decreases when the position of the rotor advances relative to the rotating magnetic field. It is stabilized by correcting the speed command.

  Since the relationship between the current I and the phase difference φ is a proportional relationship, an appropriate proportionality constant may be selected to derive φ through calculation, or accuracy in a large current value range may be obtained. For example, the relationship between I and φ may be tabulated. Since I is obtained by actual feedback, φ can be uniquely determined, and an appropriate phase difference φ can always be obtained.

  As described above, according to the calculation of the V / f control in the controller for a permanent magnet type synchronous motor according to the present invention, the torque of the permanent magnet type synchronous motor is controlled with the minimum current in consideration of the reluctance torque of the permanent magnet type synchronous motor. be able to. In addition, torque control by the minimum current is possible only by changing the rotation axis angle at the time of three-phase to two-phase conversion without requiring a complicated calculation, thereby simplifying the configuration and improving maintainability. Furthermore, in the present invention, the torque range is expanded as compared with general V / f control, and it is possible to operate with a minimum current from low speed rotation to high speed rotation.

  If such control becomes possible, it can contribute to size reduction and power saving of industrial products. For example, a motor for a compressor of an air conditioner is strongly demanded to save power because the air conditioner is a device that consumes a large amount of power together with a request for downsizing. Permanent magnet type synchronous motors have been adopted as one of the manifestations. However, if minimum current control can be achieved with a compact configuration according to the present invention, the above requirements will be met.

[Sensorless vector control]
FIG. 2 is a block diagram showing a calculation process of sensorless vector control performed by the permanent magnet synchronous motor control apparatus according to the present invention. In the sensorless vector control, the position and rotation speed of the rotor are estimated from the armature current of the permanent magnet type synchronous motor 4, and the permanent magnet type synchronous motor 4 is in response to the estimated position and rotation speed of the rotor. This is control for controlling the q-axis current i _q and the d-axis current i _{d of the} supplied armature current.

  The sensorless vector control in the control device for the permanent magnet type synchronous motor according to the present invention includes three-phase / two-phase conversion means 5, position / speed estimation calculation means 13, speed control calculation means 11, current control calculation means 12, two-phase / This is performed by the three-phase conversion means 2 and the inverter 3. In addition, the calculation in the said control apparatus is performed for every clock cycle of a system clock.

In the three-phase / two-phase conversion means 5, the acquired u-phase current i _u , v-phase current i _v , and w-phase current i _w (or two of them) in the previous clock cycle. Three-phase two-phase conversion is performed using the calculated estimated position (angle) ψ of the rotor, and the q-axis current i _q and the d-axis current _id are calculated.

In the position / speed estimation calculation 13, the q-axis current i _q and the d-axis current i _d calculated by the three-phase / two-phase conversion unit 5 and the q-axis calculated by the current control calculation unit 12 in the previous clock cycle. From the voltage v ^* _q and the d-axis voltage v ^* _d , the current estimated position ψ of the rotor, the estimated speed of the rotor, and the estimated position ψ of the rotor in the next clock cycle are calculated. The estimated position ψ and the estimated speed ω ₁ are calculated using a motor model of the permanent magnet type synchronous motor 4 (details are omitted).

The speed control calculation means 11 calculates a deviation between the speed command ω _m ^* and the estimated speed ω _{1 of the} rotor, and the q-axis current command value i _q ^* and the d-axis current command value i so that the deviation approaches 0. _d ^* and are generated. When there is no anisotropy in the motor inductance, the d-axis current command value i _d ^* is generally 0. However, the d-axis current command value i _d ^* is set to a negative value when field-weakening control is required because the speed command ω ^* is high. Further, the d-axis current command value i _d ^* does not become 0 even when the inductance of the motor has anisotropy. In order to control the permanent magnet type synchronous motor 4 with the minimum current, first, a torque corresponding to the deviation between the speed command ω _m ^* and the estimated speed ω _{1 of the} rotor is calculated or selected. Then, a combination of the q-axis current command value i _q ^* and the d-axis current command value i _d ^* required for generating the torque is selected by calculation or a table.

The current control calculation means 12 calculates a deviation between the q-axis current command value i _q ^* and the q-axis current i _q and a deviation between the d-axis current command value i _d ^* and the d-axis current i _d. The q-axis voltage v _q ^* and the d-axis voltage v _d ^* are determined so as to approach 0. The rotor estimated speed ω ₁ is used to determine the q-axis voltage v _q ^* and the d-axis voltage v _d ^* .

In the two-phase / three-phase conversion means 2, two-phase / three-phase conversion is performed on the determined q-axis voltage v _q ^* and d-axis voltage v _d ^* 3 to be supplied to the permanent magnet type synchronous motor 5. The u-phase voltage v ^* _u , the v-phase voltage v ^* _v , and the w-phase voltage v ^* _{w of the} phase drive voltage are calculated. In the two-phase / three-phase conversion, the estimated position ψ of the rotor in the next clock cycle is used. In the two-phase / three-phase conversion, the estimated position ψ of the rotor in the next clock cycle is calculated by correcting the estimated position ψ of the rotor according to the estimated speed.

In the PWM not shown as being included in the inverter 3, the three-phase drive voltage having the calculated u-phase voltage v _u ^* , v-phase voltage v ^* _v , and w-phase voltage v _w ^* is the permanent magnet type synchronous motor 4. A PWM signal for controlling the inverter 3 is generated so as to be supplied to.

The advantage of sensorless vector control is that the output torque is large for the same motor output current (i.e., for some inverters whose switching element capacity is set to a certain value). The sensorless vector control capable of independently controlling the q-axis current i _q and the d-axis current i _d can output a larger output torque than other control methods. In addition, the sensorless vector control can perform field-weakening control by controlling the d-axis current i _d . The field weakening control suppresses the counter electromotive force and enables the permanent magnet type synchronous motor 5 to be operated at high speed.

  In the above, the control by the minimum electric current of V / f control and sensorless vector control was demonstrated. The present invention has the greatest feature regarding the switching calculation of these controls.

  FIG. 3 is a current / voltage vector diagram showing a phase difference when switching from V / f control to sensorless vector control. As described above, in the calculation of the V / f control, the control is performed based on the δ-γ coordinates which are the coordinate axes of the inverter without using the information on the position / speed of the rotor. On the other hand, in sensorless vector control, the position and speed of the rotor are estimated, and control is performed with reference to the dq coordinates that are the coordinate axes of the rotor. Therefore, when switching between the two controls, it is necessary to convert the control coordinate axes.

In the figure, the motor voltage is v, the motor current is i, and the phase difference between the coordinate axis (δ-γ coordinate axis) at the time of V / f control and the coordinate axis (dq coordinate axis) at the time of sensorless vector control is θ. Since the δ-axis current iδ is controlled to zero during V / f control, the motor current is considered to be directed in the γ-axis direction. The motor current i during sensorless vector control can be divided into a d-axis current i _d and a q-axis current i _q . As shown in the figure, the phase difference θ can be expressed as θ = tan ⁻¹ (id / iq) using i _d and i _q at the time of sensorless vector control. However, θ is zero in the positive direction of the q axis.

  Since the δ-axis current is basically controlled to 0 during V / f control, the motor current i is substantially equal to the γ-axis current iγ. As the magnitude of the phase difference θ, a value tabulated in advance or a function value may be used. For example, as shown in FIG. 6, θ is set to a value proportional to the γ-axis current iγ, the phase difference θ is obtained from the γ-axis current iγ at the time of switching, and the phase difference corresponding to the different control coordinate axes is corrected. θ may be a function of the γ-axis current iγ or may be selected as a table of γ-axis current iγ and θ. If θ is set to a value proportional to the γ-axis current, there is an advantage that the calculation formula becomes simple and the calculation processing load is reduced. If there is no anisotropy in the motor inductance, the motor torque τ has a relationship of τ∝motor current I × sin θ ′ (θ ′ is the angle formed by the induced voltage and the motor current), and if θ ′ is small Since θ′≈sin θ ′, it is possible to make θ a value proportional to the γ-axis current.

  Thus, if the coordinate axes are converted, it is possible to smoothly switch from V / f control calculation to sensorless vector control calculation. In other words, since the minimum current is controlled in either control, there is almost no difference in the inverter output current for driving the permanent magnet type synchronous motor, and sudden current and voltage changes are suppressed by switching. can do. In addition, since it is not necessary to gradually change the motor current command and the motor voltage command to suppress sudden changes in voltage and current, the control algorithm can be simplified and the burden on the arithmetic processing is small.

  Next, the case of switching from sensorless vector control computation to V / f control computation will be described. FIG. 4 is a current / voltage vector diagram showing the phase difference when switching from sensorless vector control to V / f control. In the V / f control used in the present invention, since the power factor angle is used for the three-phase / two-phase conversion and the control is performed with the minimum current, when switching from the sensorless vector control calculation to the V / f control calculation, Corrects the phase difference and power factor angle.

The point where the phase difference θ is expressed as θ = tan ⁻¹ (i _d / i _q ) using the d-axis current i _d and the q-axis current i _q is a switch from V / f control calculation to sensorless control calculation. It is the same. In V / f control, a phase difference φ is provided between the phase of the motor voltage command and the phase of the motor current so as to achieve minimum current control (or maximum efficiency control). Also in sensorless vector control, since minimum current control (or maximum efficiency control) is performed, the motor factor and the motor current power factor angle φ in V / f control are the same. Therefore, when switching from sensorless vector control to V / f control, in the same way as described above, in addition to correcting the phase difference θ for the different control coordinate axes, minimum current control (or maximum efficiency control) is also achieved by V / f control. Add power factor angle φ to perform. The magnitude of the power factor angle φ is, for example, a value proportional to the motor current as shown in FIG. 7, and can be obtained from a value corresponding to the square sum of squares of d and q-axis currents at the time of switching. Further, the current value and the value of φ may be provided as a table so that they can be selected. The reason why the value of the square sum square root, substantially, the relationship of the motor torque α motor current I is composed, if ^{_{I = (i d 2 + i}} q 2) 1/2, it is square This is because the value is the sum square.

  Thus, if the coordinate axes are converted, it is possible to smoothly switch from the sensorless vector control calculation to the V / f control calculation. In other words, since the minimum current is controlled in either control, there is almost no difference in the inverter output current for driving the permanent magnet type synchronous motor, and sudden current and voltage changes are suppressed by switching. can do. In the present invention, the power factor angle is used for the three-phase / two-phase conversion, and the minimum current control may be performed extremely rationally, so that the calculation of the control can be performed without directly operating the voltage command or the current command. Can be smoothly switched. In addition, since it is not necessary to gradually change the motor current command and the motor voltage command to suppress sudden changes in voltage and current, the control algorithm can be simplified and the burden on the arithmetic processing is small.

  FIG. 8 is a graph showing a switching phase when the permanent magnet type synchronous motor is applied to a load having a periodic pulsating torque, where the horizontal axis is the phase (angle) and the vertical axis is the load. As shown in the figure, depending on the load to which the permanent magnet type synchronous motor is applied, there is a periodic torque pulsation. For example, a single rotary compressor has one torque pulsation per shaft rotation. The figure shows this.

  If there is torque pulsation, a current peak is likely to appear also in the control device on the controlling side, and it tends to become unstable during this short time (phase). In addition, when the frequency command increases and so-called field weakening control is performed to increase the torque, the current in the excitation direction also increases. In such a case, the control is not switched, and it is prevented that the control becomes unstable due to an excessive current. Specifically, the phase for switching control may be fixed to a predetermined phase from which the pulsation peak is removed. In general, when it is previously known that the current in the excitation direction or the current in the torque direction is equal to or greater than a certain value at a certain phase, the calculation of V / f control is performed at the certain phase. Do not switch between calculation and sensorless vector control. In the case of FIG. 8, the predetermined phase is, for example, a phase (point A) at which the motor current becomes an average value of the pulsation cycle.

  Thus, when there is a sudden change in the motor current waveform due to torque pulsation (fluctuation) and it is known that the change occurs at a constant phase, the control calculation is performed using a predetermined position outside the phase as a trigger. If switching is performed, a situation of an emergency stop due to an overcurrent can be avoided.

  FIG. 5 is a table showing examples of tables such as current, phase difference, and power factor angle. At the time of switching from V / f control calculation to sensorless vector control calculation, since Iγ is known to be, for example, 5.5 [A] in V / f control, the corresponding phase difference θ is 12.5. To switch to sensorless vector control. On the other hand, in the calculation of sensorless vector control, id and iq are known (the combination is such that these are the minimum current), so the phase difference θ and the power factor angle φ are selected from their absolute values, etc. Change the coordinates. In general, it is expected that the sensorless vector control is performed at the low speed and the V / f control is performed at the high speed. In a region where the control is possible, it is possible to switch between each other and smoothly.

  As described above, the control device for a permanent magnet type synchronous motor according to the present invention is a control device for a permanent magnet type synchronous motor that smoothly switches between V / f control computation and sensorless vector control computation with a simple configuration. Useful for. In particular, it is suitable for a control device for a permanent magnet type synchronous motor whose cost is to be reduced.

It is a block diagram which shows the calculation process of V / f control performed with the control apparatus of the permanent magnet type synchronous motor which concerns on this invention. It is a block diagram which shows the calculation process of the sensorless vector control performed with the control apparatus of the permanent magnet type | mold synchronous motor which concerns on this invention. It is a current / voltage vector diagram showing a phase difference at the time of switching from V / f control to sensorless vector control. FIG. 6 is a current / voltage vector diagram showing a phase difference when switching from sensorless vector control to V / f control. It is a graph which shows the example of tables, such as an electric current, a phase difference, and a power factor angle. It is a graph which shows the relationship between an electric current and a phase difference, a horizontal axis is electric current Iγ, and a vertical axis is a phase difference. It is a graph which shows the relationship between an electric current, a phase difference, and a power factor angle, a horizontal axis is electric current Iq and a vertical axis | shaft is a phase difference and a power factor angle. It is a graph which shows the switching phase when applying a permanent magnet type synchronous motor with respect to the load which has a regular pulsation torque, a horizontal axis is a phase (angle), and a vertical axis | shaft is a load.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Voltage command calculating means 2 2 phase / 3 phase converting means 3 Inverter 4 Permanent magnet type synchronous motor 5 3 phase / 2 phase converting means 6 Power factor angle calculating means 7 Gain 8 Integrator 11 Speed control calculating means 12 Current control calculating means 12 13 Speed estimation calculation means

Claims (5)

The inverter is operated using a voltage command proportional to the speed command, and the current applied to the motor is converted into a three-phase / two-phase using the output voltage phase angle and the desired power factor angle, and fed back to the speed command. / F control calculation,
The rotor position of the motor is estimated from the voltage command and the motor applied current to be fed back, and control is performed using the current command that is the minimum current by a predetermined calculation or selection from the table from the estimated speed. Calculation of sensorless vector control and
A control device for a permanent magnet type synchronous motor, characterized in that it has an arithmetic device for controlling the motor by switching between them.   2. The permanent magnet according to claim 1, wherein a phase difference between an inverter coordinate system and a rotor coordinate system of the motor is corrected when switching from the calculation of the V / f control to the calculation of the sensorless vector control. Type synchronous motor control device.   2. The phase difference and power factor control angle between the inverter coordinate system and the rotor coordinate system of the motor are corrected when switching from the sensorless vector control calculation to the V / f control calculation. Or a control device for a permanent magnet type synchronous motor according to 2;   The permanent magnet type synchronization according to any one of claims 1 to 3, wherein the V / f control calculation and the sensorless vector control calculation are not switched when the current in the excitation direction is a predetermined value or more. Motor control device.   In the case of a load having a constant phase pulsation torque, the phase for switching between the calculation of the V / f control and the calculation of the sensorless vector control is fixed to a predetermined phase from which a pulsation peak is removed. 4. The control device for a permanent magnet type synchronous motor according to any one of 4 above.

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