JP4136104B2 - Control device for permanent magnet synchronous motor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
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 used as a drive source for a mechanical device such as an elevator.
[0002]
[Prior art]
In recent years, by using a synchronous motor that uses a small and powerful permanent magnet as a field, the synchronous motor and the drive device including the synchronous motor have been reduced in size and improved in efficiency. Application to various machine devices such as an elevator device is being advanced.
[0003]
Normally, to control the torque of a synchronous motor, not only the magnitude of the current but also the magnetic pole position (rotation angle) of the synchronous motor is grasped to control the current phase corresponding to the magnetic pole position of the synchronous motor. It is essential to do. For detection of the magnetic pole position, a magnetic pole position detector is practically used. Japanese Patent Laid-Open No. 10-80188 discloses an application of this to an elevator. However, if a magnetic pole position detector is used to detect the magnetic pole position, a magnetic pole position detector must be provided at the end of the motor. Sometimes it is necessary to align the motor shaft and the detection shaft. In order to eliminate this problem, magnetic pole position sensorless driving has been studied. For example, there is the 1998 National Institute of Electrical Engineers of Japan “NO, 883 Permanent magnet synchronous motor simple magnetic pole position sensorless system performance evaluation”.
[0004]
[Problems to be solved by the invention]
However, the conventional magnetic pole position sensorless drive cannot be used unless the motor is a salient pole type, and in some cases, torque ripple may be generated from the motor.
[0005]
In view of the above-described various problems, an object of the present invention is to provide a permanent magnet type synchronous motor that can detect a magnetic pole position without providing a magnetic pole position detector regardless of the type of the permanent magnet type synchronous motor. It is to provide a control device.
[0006]
[Means for Solving the Problems]
The present invention employs the following means in order to solve the above problems.
[0007]
A permanent magnet synchronous motor controlled by a variable voltage and a variable frequency output from a power converter, and a control device for a permanent magnet synchronous motor in a mechanical device driven by the permanent magnet synchronous motor. During operation, the power converter is controlled based on the magnetic pole position obtained by integrating the pulse signal according to the rotation angle of the permanent magnet type synchronous motor, and the magnetic pole position obtained by the integration is the permanent magnet together it is modified by the magnetic pole phase obtained by calculating the voltage or the voltage command signal is induced during the rotation of the formula synchronous motor, in a state of not outputting the variable voltage and the variable frequency from the power converter, the mechanical device The brake device that holds the stop is released, and based on the voltage induced during the rotation of the permanent magnet synchronous motor accompanying the release. Detecting the initial value of the magnetic pole position Te.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0015]
FIG. 1 is a diagram illustrating an example of an elevator apparatus to which a control device for a permanent magnet type synchronous motor according to the present embodiment is applied.
[0016]
In the figure, 11 is a passenger car, 12 is a counterweight, 13 is a rope on which the passenger car 11 and the counterweight 12 are suspended at both ends, 51 is a permanent magnet synchronous motor, and 52, 53 and 54 are permanent magnet synchronous. The sheave, the brake drum, and the encoder 21 connected to the rotation shaft of the motor 51 output a brake signal to the brake device 31 that controls the brake drum 53, and the rotation angle of the permanent magnet type synchronous motor 51 is detected by the encoder 54. This is a control device that outputs a speed control signal to the permanent magnet type synchronous motor 51.
[0017]
In this elevator apparatus, when the permanent magnet type synchronous motor 51 is driven, the sheave 52 rotates, and the car 11 and the counterweight 12 are moved up and down in the hoistway (not shown) via the rope 13. When a current flows through the coil of the brake device 31 in response to a command from the control device 21, the brake shoe pressing the brake drum 53 is released, and the brake is released. The encoder 54 outputs a pulse according to the rotation angle of the permanent magnet type synchronous motor 51, and its frequency is proportional to the rotation speed of the permanent magnet type synchronous motor 51.
[0018]
In the figure, the encoder 54 is connected to the shaft end of the permanent magnet type synchronous motor 51. However, it is only necessary to be able to detect a pulse signal proportional to the rotation angle of the motor, so there is no need to stick to the shaft end. For example, an encoder may be mounted along the sheave 52 and a signal may be obtained in accordance with the rotation of the sheave 52, or may be mounted on the car 11 or the counterweight 12 to obtain a signal in accordance with its movement. That is, even if the encoder signal is not proportional to the absolute value of the rotation angle of the motor, it is only necessary to know the relative movement, so that the degree of freedom of installation of the encoder 54 is increased.
[0019]
FIG. 2 is a block diagram showing an outline of the configuration of the control device 21 shown in FIG.
[0020]
In the figure, 22 is an AC power source, 211 is an inverter that converts the power from the AC power source 22 by PMW control according to a control signal from the current control calculation unit 214 and outputs a variable voltage and a variable frequency to the permanent magnet synchronous motor 51. , 212 is a speed command, 213 is a speed control calculation unit that outputs a torque command signal in accordance with the deviation between the speed command signal based on the speed command 212 and the rotational speed signal from the encoder 54, and 214, as described in detail later. Based on the speed command signal from the speed control calculation unit 213, the rotation speed signal from the encoder 54, the armature current signal detected by the current detector 217, and the magnetic pole position signal detected by the magnetic pole position estimation unit 215. Thus, a current control calculation unit 215 that outputs a predetermined control signal to the inverter 211 is a power control unit, as will be described in detail later. The magnetic pole position is calculated based on the armature current signal detected by the detector 217 and the terminal voltage signal of the permanent magnet type synchronous motor 51 detected by the voltage detector 216, and the magnetic pole position detected by the encoder 54 is corrected. It is a magnetic pole position estimation part. As described above, estimation of the magnetic pole position is indispensable for speed control.
[0021]
The vector control of the speed of the permanent magnet type synchronous motor based on the above magnetic pole position signal is, for example, “Michio Nakano et al .: Servo Technology and Power Electronics (issued September 1994), pages 136- 137 ”and“ Nakano Takayoshi: Vector control of AC motor (published in Nikkan Kogyo Shimbun, March 1996) pages 58-59 ”, detailed description of the operation is omitted. To do.
[0022]
Next, the principle of estimating the magnetic pole position will be described.
[0023]
Assuming that the terminal voltage (phase voltage) of the permanent magnet type synchronous motor 51 is e _t , the induced voltage (phase voltage) in the permanent magnet type synchronous motor 51 is e ₀ , the synchronous inductance is L, and the armature current is i, the following equation There is a relationship.
[0024]
_{e 0 = e t -L (di} / dt) ( number 1)
In this equation, the armature resistance is relatively small at a certain speed and is ignored because it is relatively small. However, it may be taken into account in order to increase accuracy.
[0025]
The magnetic flux Φ of the motor can be obtained from Equation 1 as follows:
[0026]
_{Φ = ∫e 0 dt = ∫e t} dt-Li ( Number 2)
As understood from Equation 2, by knowing the terminal voltage _et , the synchronous inductance L, and the armature current i, the magnetic pole position of the magnetic flux Φ of the motor can be obtained by calculation.
[0027]
FIG. 3 is a block diagram showing a configuration of the magnetic pole position estimation unit 215 shown in FIG.
[0028]
In the figure, 2151 is an integrator for integrating the terminal voltage e _t of the voltage detector permanent magnet detected by 216 the synchronous motor 51, 2152 synchronous inductance L to the armature current i detected by the current detector 217 A gain setting unit for multiplication, 2153 is an adder for calculating the magnetic flux Φ in accordance with Equation 2, 2154 is a comparator for detecting the zero point of the magnetic pole phase where the calculated magnetic flux Φ crosses zero, and 2155 is the permanent magnet type synchronous motor 51. A speed determination unit 2156 that determines whether the rotation speed is suitable for estimation of the magnetic pole position, and a switch 2157 that is closed by a command from the speed determination unit 2155 when the rotation speed suitable for estimation of the magnetic pole position is reached. The pulse signal according to the rotation angle from the encoder 54 is integrated to output a magnetic pole position signal, and the zero cross from the comparator 2154 No. every time is output, an integrator for correcting the magnetic pole position signal to modify the integral value.
[0029]
As described above, by providing the speed determination unit 2155 and the switch 2156, the correction operation in the low speed region where the induced voltage e ₀ is not sufficient is stopped to improve the accuracy.
[0030]
The correction of the magnetic pole position described above is not the zero point, and the magnetic flux signal at that time may be used.
[0031]
Moreover, although the magnetic pole position estimation part 215 was comprised and comprised with the hardware circuit, of course, you may carry out by software, such as a microcomputer. Furthermore, although the detection of the terminal voltage e _t as performed by detecting the terminal voltage of the main circuit, can also be obtained from a signal for controlling the inverter 211. That is, the control signal from the current control calculation unit 214 to the inverter 211 is a voltage command signal as will be described later, since the signal is proportional to the terminal voltage e _t, it may be used a control signal to the inverter 211.
[0032]
Next, magnetic pole position estimation immediately after power-on will be described using the flowchart shown in FIG.
[0033]
In step 1, the power source 22 is turned on to establish a control power source and a main circuit power source. Next, in step 2, an initial position estimation mode is established in which it is known that the magnetic pole position is estimated immediately after the power is turned on. At this time, the armature current i of the permanent magnet type synchronous motor 51 is kept at zero. Therefore, the gate circuit of the inverter 211 is stopped or the current command from the current control calculation unit 214 is set to zero. Next, in Step 3, the brake of the brake drum 53 by the brake device 31 is released by a command not shown. By releasing the brake, the car 11 naturally moves up and down by its gravity. Immediately after the power is turned on, there are often no people or luggage on the car 11, and at that time, the weight of the counterweight 12 is heavier than the weight of the car 11, so the car 11 rises due to this weight difference. Conversely, the car 11 is lowered when the rated load is applied. If the weights of the car 11 and the counterweight 12 are balanced, an additional weight may be placed on the car 11. In any case, the vehicle is raised and lowered naturally by the weight difference between the car 11 and the counterweight 12. Next, in step 4, it is determined whether the permanent magnet type synchronous motor 51 has reached a predetermined speed. Here, the speed is determined in order to avoid measurement errors. Normally, for example, if the acceleration is accelerated to 5% or more of the rated rotational speed, the induced voltage e ₀ of the permanent magnet synchronous motor can be sufficiently obtained. When the permanent magnet type synchronous motor 51 reaches a predetermined speed, the induced voltage e ₀ of the permanent magnet type synchronous motor 51 at that time is measured in accordance with Equation 1 in step 5. Here, the induced voltage e ₀ is equal to the terminal voltage e _t. Since磁誘electromotive voltage e ₀ is changed to correspond to the magnetic pole position, it is possible to detect the magnetic pole phase from the induced voltage e _0. For example, a zero cross point of a sinusoidal induced voltage waveform may be measured to detect the magnetic pole phase (see FIG. 3). Or you may measure a phase from the mutual magnitude | size of three voltages using the thing of 3 phase alternating current. In step 6, since the induced voltage phase corresponds to the magnetic pole phase of the permanent magnet synchronous motor 51, the magnetic pole position is calculated from the voltage phase. If the magnetic pole position can be estimated here, the value of the magnetic pole position is immediately stored as an initial value. Thereafter, in step 7, the stored magnetic pole position is used as an initial value, and the pulse signal from the encoder 54 is integrated (added or subtracted) depending on the rotation direction, and the magnetic pole position at that time is continuously estimated. Since this calculation corresponds to the rotation angle of the permanent magnet type synchronous motor 51, it is equivalent to the magnetic pole position. Next, in step 8, the initial position estimation mode is turned off and set to a normal operation mode in which a current command is given by a speed command, the magnetic pole position estimation in step 7 is continued, and the operation control of the control device 21 is performed.
[0034]
It should be noted that the setting of the initial position estimation mode in step 2 can be performed automatically after recognizing that it is immediately after the power is turned on to estimate the magnetic pole position. In addition, the initial position estimation mode may be set manually by a maintenance staff or the like. For example, in order to recognize that it is the initial position estimation mode, the initial position estimation is executed only while the button is pressed, and the brake device 31 operates immediately after the button is released, and the car 11 is stopped. Good. In addition, after the calculation in step 7, the operation may be continued according to the command at that time, or after being temporarily stopped, the operation may be performed again according to the command.
[0035]
As described above, according to the present embodiment, the magnetic pole position of the permanent magnet type synchronous motor 51 immediately after the power is turned on can be estimated without the magnetic pole position detector, and the integral value of the pulse signal from the encoder 54 and the permanent value can be estimated. Since the rotation angle of the magnetic synchronous motor 51, that is, the magnetic pole position corresponds to 1: 1, the magnetic pole position can be obtained by integrating the pulse from the encoder 54. As a result, the magnetic pole position can be calculated regardless of the speed from the extremely low speed to the rated speed.
[0036]
Further, when the elevator apparatus is stopped, a value obtained by integrating pulses so far may be stored. At the next start-up, the stored value can be made to correspond to the magnetic pole phase and the operation can be started. Therefore, the estimation of the magnetic pole position immediately after power-on may be performed only when the integrated value is no longer maintained. For this reason, for example, when the operation of the elevator is suspended, only the main circuit power supply may be shut off and a circuit that performs integration may be utilized. Furthermore, when the operation is stopped for a long period of time, only the integrated value is stored in the nonvolatile memory, and this value may be used in the next operation.
[0037]
Next, correction of the magnetic pole position during operation after estimation of the initial position of the magnetic pole position will be described with reference to FIG.
[0038]
As described in the flowchart shown in FIG. 4, even if the initial position of the magnetic pole position is estimated in step 7, when the integration calculation of the pulse signal from the encoder 54 after estimation of the magnetic pole position is performed, the pulse from the encoder 54 If noise or the like is mixed in the signal and it is misintegrated, an error may occur in the magnetic pole phase calculation.
[0039]
Therefore, in this embodiment, during operation of the elevator apparatus, the integrator 2157 of FIG. 3 uses the magnetic pole position obtained from the integrated value of the pulse signal from the encoder 54 as the zero point of the magnetic pole phase of the magnetic flux Φ obtained from the comparator 2154. Is always corrected, and operation control is performed based on the corrected magnetic pole position.
[0040]
Next, the configuration and operation of the current control calculation unit 214 shown in FIG. 2 will be described with reference to FIG.
[0041]
FIG. 5 is a diagram illustrating an example of a specific configuration of the current control calculation unit 214. This basic configuration is well-known, for example, IEEJ Transaction D, Vol. 117, No. 5 (May 1997), page 539. This is described in FIG.
[0042]
In the figure, reference numeral 2141 denotes a three-phase armature current iu, iv, iw detected by the current detector 217 based on the magnetic pole position estimated by the magnetic pole position estimation unit 215, and the magnetic flux direction axis component Id of the armature current. Id / Iq calculation unit 2142 that calculates a quadrature component Iq between the magnetic flux direction axis component Id and an adder that calculates a deviation between the current command component Iq ^* output from the speed control calculation unit 213 and the orthogonal component Iq, 2143 is an adder for calculating a deviation between the current command component Id ^* and the magnetic flux direction axis component Id, 2144 is a deviation amplifier (ACR-q), 2145 is a deviation amplifier (ACR-d), and 2146 is a current command component Iq ^* . A multiplier 2147 for the motor rotational speed (electrical rotational angular frequency) ω obtained from the encoder 54, 2147 is the motor rotational speed obtained from the current command component Id ^* and the encoder 54. Multipliers of degrees (electric rotation angular frequency) ω, 2148 and 2149 are gain setters for setting a gain corresponding to the synchronous inductance L, 2150 is a gain setter for setting a gain corresponding to the magnetic flux Φ, and 2151 The adder 2152 adds the current deviation Iq ^* −Iq and the output from the gain setting devices 2149 and 2150 for compensating the current deviation Iq ^* −Iq, and outputs the voltage command signal Eq ^* to the inverter 211. The current deviation Id ^* −Id and the output from the gain setting device 2148 for compensating the current deviation Id ^* −Id are added, and the voltage command signal Ed ^* is output to the inverter 211.
[0043]
As described above, this current control calculation is characterized in that the armature current is controlled by being divided into d and q axis components.
[0044]
The current command component Id ^* is normally zero, but Id ^* may be given so as to obtain a required power factor in order to perform power factor control of the motor.
[0045]
In the above-described mode in which the current at the time of detecting the magnetic pole position immediately after the power is turned on is zero, if the current commands Id ^* and Iq ^* are set to zero, the current can be prevented from flowing through the motor.
[0046]
Further, when the PWM control of the inverter 211 is executed, if a sine wave instantaneous voltage command signal is required, the calculation unit 2141 may perform the reverse calculation. Since this calculation is well known, it will be omitted.
[0047]
Although the above-described current control calculation unit 214 has been described as a hardware circuit, it goes without saying that the current control calculation unit 214 may be performed in software using a microcomputer or the like.
[0048]
Furthermore, the present invention can be applied not only to an elevator, but also to other devices in which a motor naturally moves due to a reaction force from a load when a brake is released, for example, a machine such as a hoist.
[0049]
As described above, according to the present invention, since the magnetic pole position can be estimated without using the magnetic pole position detector, the elevator apparatus can be operated smoothly.
[0050]
【The invention's effect】
As described above, according to the present invention, since the magnetic pole position detector is not used for detecting the magnetic pole position necessary for the control of the permanent magnet type synchronous motor, the degree of freedom in designing the motor and the machine is increased. Since no position detector is used, maintenance is easy and costs can be reduced. Further, the magnetic pole position can be easily detected at the time of start-up, and the function of correcting the magnetic pole position is provided during operation, so that the magnetic pole position can be detected with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an elevator apparatus to which a controller for a permanent magnet type synchronous motor according to an embodiment of the present invention is applied.
FIG. 2 is a block diagram showing an outline of a configuration of a control device 21 shown in FIG.
3 is a block diagram showing a configuration of a magnetic pole position estimation unit 215 shown in FIG.
FIG. 4 is a flowchart showing a processing procedure for magnetic pole position estimation immediately after power-on.
5 is a block diagram showing a configuration of a current control calculation unit 214 shown in FIG.
[Explanation of symbols]
21 control device 211 inverter 212 speed command 213 speed control calculation unit 214 current control calculation unit 2141 Id / Iq calculation unit 215 magnetic pole position estimation unit 2151 integrator 2152 level setter 2153 adder 2154 comparator 2155 speed determination unit 2157 integrator 22 Power supply 31 Brake device 51 Permanent magnet type synchronous motor 53 Brake drum 54 Encoder

Claims (3)

In a permanent magnet synchronous motor controlled by a variable voltage and a variable frequency output from a power converter, and a control device for a permanent magnet synchronous motor in a mechanical device driven by the permanent magnet synchronous motor,
During operation of the mechanical device, based on the magnetic pole position obtained by integrating the pulse signal according to the rotation angle of the permanent magnet type synchronous motor, the power converter is controlled,
Magnetic pole position obtained by the integration, with is modified by the magnetic pole phase obtained by calculating the voltage or the voltage command signal is induced during rotation of the permanent magnet type synchronous motor,
In a state where the variable voltage and the variable frequency are not output from the power conversion device, the brake device that holds the stop of the mechanical device is released, and the voltage induced when the permanent magnet synchronous motor rotates due to the release is released. An initial value of the magnetic pole position is detected based on the permanent magnet type synchronous motor control device. 2. The control of a permanent magnet synchronous motor according to claim 1 , wherein the initial value of the magnetic pole position is detected by calculating the detected induced voltage to obtain a magnetic flux and obtaining the magnetic flux position from a zero cross position of the magnetic flux. apparatus. In any one of claims 1 to claim 2, wherein the detection of the initial value of the magnetic pole position, the permanent magnet type speed during the rotation and carrying out upon reaching a predetermined speed synchronous motor Control device.

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