JP3569164B2 - Starting method of elevator driven by permanent magnet type synchronous motor - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method for starting an elevator driven by a permanent magnet synchronous motor.
[0002]
[Prior art]
By using a synchronous motor that uses a small and strong permanent magnet for the field, the synchronous motor and the drive device including the synchronous motor can be downsized and the efficiency can be improved. Is being applied.
[0003]
In order to control the torque of the synchronous motor, not only the magnitude of the current is controlled, but also the magnetic pole position (magnetic pole phase / rotation angle) of the synchronous motor to control the current phase corresponding to the magnetic pole position of the synchronous motor. It is essential to understand For detecting the magnetic pole position, a magnetic pole position detector is practically used.
[0004]
For the detection of the magnetic pole position, there are methods for physically detecting the magnetic pole position and estimating the actual magnetic pole position from the induced voltage of the synchronous motor. Japanese Patent Laying-Open No. 1-129796 discloses the latter, that is, a method of estimating a magnetic pole position from an induced voltage.
[0005]
[Problems to be solved by the invention]
However, in order to use a physical magnetic pole position detector to detect the magnetic pole position, a magnetic pole position detector must be provided at the end of the motor shaft. When mounting the position detector, it is necessary to align the position of the motor shaft with the position of the detection shaft.
[0006]
When estimating the actual magnetic pole position from the induced voltage of the synchronous motor, the drawbacks associated with physically attaching the magnetic pole position detector can be avoided, but no induced voltage is generated when the synchronous motor is stopped. Therefore, the detection of the magnetic pole position becomes impossible.
[0007]
An object of the present invention is to propose a method of starting an elevator using a permanent magnet type synchronous motor that enables estimation of a magnetic pole position (magnetic pole phase) without providing a physical magnetic pole position detector.
[0008]
Furthermore, an object of the present invention is to propose an elevator starting method using a permanent magnet type synchronous motor capable of detecting a magnetic pole position even when the elevator is stopped, that is, when the synchronous motor is stopped.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention provides a permanent magnet type synchronous motor driven by a variable voltage / variable frequency power converter, a mechanical device driven by the synchronous motor, and Means for estimating the position of the magnetic pole of the synchronous motor by detecting the induced voltage of the synchronous motor, and after releasing the brake that holds the synchronous motor at the stop position, start by applying a low-frequency voltage to the synchronous motor. When the synchronous motor reaches a predetermined speed, the application of voltage is stopped to shift to free run, and a magnetic pole position is detected from a zero-cross point of an induced voltage generated with the rotation of the synchronous motor, and the synchronous motor is detected. Is controlled.
[0010]
Further, the present invention provides a permanent magnet synchronous motor driven by a variable voltage / variable frequency power converter, a mechanical device driven by the synchronous motor, and detecting an induced voltage when the synchronous motor rotates. Means for estimating the magnetic pole position of the synchronous motor, detecting an unbalanced portion of the load of the synchronous motor from an output of a load detector of a car, and, in the case of an unbalanced load, a brake for stopping and holding the synchronous motor. To shift to free run, detect the magnetic pole phase from the zero-cross point of the induced voltage generated by the rotation of the synchronous motor, and in the case of a balanced load, apply the low frequency voltage to the motor after releasing the brake When the motor reaches a predetermined speed, the motor stops applying voltage and shifts to the free run. Detecting a magnetic pole position from the zero-cross point of the voltage, and controls the synchronous motor.
[0011]
Further, the present invention provides a permanent magnet type synchronous motor driven by a variable voltage / variable frequency power converter, a mechanical device driven by the synchronous motor, and detecting an induced voltage when the synchronous motor rotates. Means for estimating the magnetic pole position of the synchronous motor, releasing the brake for stopping and holding the synchronous motor without applying a voltage to the synchronous motor to shift to free run, and as a result of the release, the synchronous motor When the synchronous motor rotates, the magnetic pole position is detected from the zero-cross point of the induced voltage generated by the rotation of the synchronous motor, and when the synchronous motor does not rotate, the magnetic pole is started by applying a low-frequency voltage, and the synchronous motor starts to operate at a predetermined speed. When the speed is reached, the application of voltage is stopped and the mode shifts to free run. Detects and controls the synchronous motor.
[0012]
The detection of the rotational position by the signal from the speed detector keeps its value even when the synchronous motor is stopped, and this value can be used as the magnetic pole phase at the next start. After the magnetic pole phase is detected, a low frequency voltage is applied to the synchronous motor, and the synchronous motor can be moved to the nearest floor without stopping.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0014]
FIG. 1 is a block diagram showing 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. The car 11 and the counterweight 12 are suspended from both ends of a rope 13, and the rope 13 is wound around a sheave 52 fixed to a rotating shaft of a permanent magnet type synchronous motor 51.
[0015]
The sheave 52 around which the rope 13 is wound, the brake drum 53 for braking and stopping the car 11, and the encoder 54 for detecting the rotation of the synchronous motor 51 are connected to the rotating shaft of the permanent magnet synchronous motor 51, respectively.
[0016]
The control device 21 outputs a brake signal to the brake device 31 that controls the brake drum 53, detects the rotation angle of the permanent magnet synchronous motor 51 by the encoder 54, and outputs a speed control signal to the permanent magnet synchronous motor 51. Output.
[0017]
In this elevator apparatus, when the permanent magnet synchronous motor 51 is driven, the sheave 52 rotates, and the car 11 and the counterweight 12 move up and down in the hoistway (not shown) via the rope 13. When a current flows through the coil of the brake device 31 according to a command from the control device 21, the brake shoe 32 pressing the brake drum 53 is released, and the brake is not applied. The encoder 54 outputs a pulse according to the rotation angle of the permanent magnet synchronous motor 51, and its frequency is proportional to the rotation speed of the permanent magnet 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, the encoder 54 need only be able to detect a pulse signal proportional to the rotation angle of the synchronous motor. For example, the encoder 54 may be mounted along the sheave 52 to obtain a signal in accordance with the rotation of the sheave 52, or may be mounted to the car 11 or the counterweight 12 to obtain a signal in accordance with the movement. . That is, the signal of the encoder 54 need not be proportional to the absolute value of the rotation angle of the motor, but only needs to know the relative movement. Therefore, the degree of freedom in installing the encoder 54 is increased.
[0019]
The control device 21 includes an inverter (power converter) 211, a speed control calculator 213, a current control calculator 214, and a magnetic pole position estimator 215, and is connected to the AC power supply 22. The inverter 211 converts power from the AC power supply 22 by PWM 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.
[0020]
The speed control calculation unit 213 outputs a torque command signal according to a deviation between a speed command signal based on the speed command 212 and a rotation speed signal from the encoder 54. The current control calculation unit 214 outputs a start current command signal for estimating the magnetic pole phase from the start current command unit 218 as described later, or outputs the speed control calculation unit 213 from the speed control calculation unit 213 during operation of the elevator apparatus. Based on the speed command signal, the rotation speed signal from the encoder 54, the armature current signal detected by the current detector 217, and the magnetic pole position signal estimated by the magnetic pole position estimating unit 215, a predetermined signal is given to the inverter 211. Outputs control signal. When a starting current command signal for estimating the magnetic pole phase is output from the starting current command unit 218, the current control calculation unit 214 supplies the inverter 211 with a low-frequency voltage to the synchronous motor 51, and drives the synchronous motor 51 at a low frequency. Operate to rotate.
[0021]
The magnetic pole position estimating unit 215, based on the armature current signal detected by the current detector 217 and the terminal voltage signal of the permanent magnet synchronous motor 51 detected by the voltage detector 216, as will be described later, Phase).
[0022]
The starting current command unit 218 outputs a starting current command signal for correcting the magnetic pole position (magnetic pole phase) output by the encoder 54, and rotates the synchronous motor 51 at a low frequency. As described above, in order to perform speed control, estimation of the magnetic pole position is indispensable.
[0023]
The vector control of the speed of the permanent magnet synchronous motor based on the magnetic pole position signal is described in, for example, "Michio Nakano et al .: Servo technology and power electronics (published by Kyoritsu Shuppan, September 1994), page 136- 137 ”and“ Takayoshi Nakano: Vector Control of an AC Motor (Nikkan Kogyo Shimbunsha, March 1996), pp. 58-59 ”, and detailed description of the operation is omitted. I do.
[0024]
Next, a processing procedure of magnetic pole position estimation immediately after power-on will be described with reference to a flowchart shown in FIG.
[0025]
In step S1, the power supply 22 is turned on to establish a control power supply and a main circuit power supply. Next, in step S2, it is determined whether or not the mode (phase detection mode) for estimating the magnetic pole position is set. If not in the magnetic pole position estimation mode, the normal operation starts.
[0026]
If it is the magnetic pole position estimation mode, the control device 21 releases the brake 31 in step S3. As a result, if the load on the synchronous motor 51 is unbalanced, the motor starts rotating in any direction naturally, and an induced voltage as shown in FIG. The magnitude and direction of the load are detected by the load detector 35, but in the case of an unbalanced load, the starting current command unit 218 does not perform any special operation.
[0027]
The voltage between the terminals of the synchronous motor 51, that is, the induced voltage is detected by the voltage detector 216. On the other hand, the pulse signal from the encoder 54 is provided to the magnetic pole position estimating unit 215 and integrated. Since this integrated value corresponds to the rotation speed of the motor at a ratio of 1: 1, it is equivalent to the calculated value of the relative phase of the magnetic pole. As a result, an integrated value of the magnetic pole phase as shown in FIG.
[0028]
Next, the integrated phase is corrected by regarding the zero-cross point of the induced voltage as the true value of the magnetic pole phase. At this time, since the voltage detection value generally includes observation noise, a speed threshold value at which the influence of the observation noise on the induced voltage is sufficiently reduced is given in advance, and phase correction is performed after the speed exceeds the threshold value. . In this way, the estimation of the magnetic pole position of the synchronous motor 51 is continuously performed. Thereafter, the magnetic pole phase estimation mode is turned off, and normal speed control is performed.
[0029]
When the load on the synchronous motor 51 is balanced, the synchronous motor 51 does not rotate even if the brake 31 is released. In this case, the load detector 35 detects the load balance and supplies the signal to the starting current command unit 218. Therefore, the starting current command unit 218 controls the inverter 211 via the current control calculation unit 214 to apply a low-frequency AC current to the synchronous motor 51 and rotate the motor by gradually increasing the frequency. When the rotation speed exceeds the set value, the application of the current is stopped and the mode is shifted to the free run. During this free-run period, the magnetic pole phase is calculated by the above method. After that, normal operation starts.
[0030]
With the above control, it is possible to estimate the magnetic pole position of the motor immediately after turning on the power without using the magnetic pole position detector, and the operation is performed. It is possible to automatically shift to the initial position estimation mode by recognizing that it is immediately after the power is turned on.
[0031]
The mode may be automatically shifted to the initial position estimation mode by an operation of a maintenance person or the like. In the case of manual shift, the initial position estimation is executed only while the button is being pressed by a button or the like in order to recognize the initial position estimation mode. When the button is pressed, the brake 31 operates immediately and the car 11 is moved. You may make it stop. After the calculation of the rotation angle, the operation may be continued in accordance with the command at that time, or the brake 31 may be turned on as shown in step S8 of FIG.
[0032]
Next, a method of detecting a position during operation after estimating the initial position will be described. As described above, the integral value of the pulse signal from the speed detector 54 and the rotation angle of the motor, that is, the magnetic pole phase corresponds to 1: 1. Therefore, the magnetic pole phase is obtained by integrating the pulses of the speed detector 54. When stopped, the integrated value of the pulse is stored in the storage device. At the time of restart, the operation is restarted using the retained magnetic pole phase. The startup as shown in FIG. 2 is performed when the integrated phase has disappeared, for example, immediately after turning on the power or at the time of an accident.
[0033]
Next, the principle of magnetic pole position estimation during operation will be described.
[0034]
First, 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, In general, the following relationship is obtained.
[0035]
_{e 0 = e t -L (di} / dt) ( number 1)
In this equation, the armature resistance is neglected at a certain speed or higher because it is relatively small, but may be considered in order to increase the accuracy.
[0036]
The magnetic flux Φ of the motor is obtained from Expression 1 as shown below.
[0037]
_{Φ = ∫e 0 dt = ∫e t} dt-Li ( Number 2)
As is clear from Equation 2, if the terminal voltage _et , the synchronous inductance L, and the armature current i can be known, the magnetic pole phase of the magnetic flux Φ of the motor can be obtained by calculation.
[0038]
Figure 4 is a block diagram showing the configuration of a magnetic pole position estimation unit 215 shown in FIG. 1, the integrator 2151 for integrating the terminal voltage e _t of the permanent magnet synchronous motor 51 is detected by the voltage detector 216, a current detection A gain setting unit 2152 for multiplying the armature current i detected by the unit 217 by the synchronous inductance L, an adder 2153 for calculating the magnetic flux Φ according to Equation 2, and detecting a zero point of a magnetic pole phase at which the calculated magnetic flux Φ crosses zero. The comparator 2154, a speed determination unit 2154 that determines whether the rotation speed is suitable for estimating the magnetic pole position of the permanent magnet type synchronous motor 51, and when the rotation speed suitable for the estimation of the magnetic pole position is reached, the speed determination unit 2155 The switch 2156 which is closed by the instruction of the above-mentioned command, the encoder 5 is added to the initial value of the magnetic pole position obtained and stored as a result of the above-described processing immediately after power-on. And outputs a magnetic pole position signal by integrating (adding or subtracting) the pulse signal from the comparator in accordance with the rotation direction, and outputs a magnetic pole position signal having an integrated value corrected each time a zero cross signal is output from the comparator 2154. And an integrator 2157 that performs the operation.
[0039]
Here, during the operation of the elevator apparatus, the magnetic pole position estimation unit 215 via a terminal voltage e _t, and the current detector 217 via a voltage detector 216 for detecting the armature current i.
[0040]
The detected terminal voltage e _t is integrated by integrator 2151 and the detected armature current i synchronous inductance L by the gain setting device 2152 is multiplied, each output, according to Equation 3, added by the adder 2153 Is done.
[0041]
The magnetic flux Φ is output from the adder 2153, and the output of the adder 2153 further detects the zero point of the magnetic pole phase that crosses zero in the comparator 2154, and every time the zero cross signal is output, the integrated value of the integrator 2157 is corrected. The magnetic pole position signal is output. With this correction, it is possible to prevent noise or the like from being included in the pulse signal from the encoder 54 and to continue to output an erroneous magnetic pole position signal obtained by erroneously integrating the noise.
[0042]
As described above, in the present embodiment, the estimation of the electrode position during the operation of the elevator apparatus is performed by setting the electrode position estimated by the process immediately after turning on the power as an initial value, and setting the initial value to the pulse signal from the encoder 54 in the rotation direction. The electrode position during operation obtained by integration (addition or subtraction) is corrected by a zero cross signal based on the magnetic flux Φ obtained by a separate calculation.
[0043]
According to the present embodiment, the magnetic pole position can be estimated from the extremely low speed to the rated speed regardless of the speed.
[0044]
When the elevator device is stopped, the value integrated so far by the integrator 2157 may be stored. Then, at the next start-up, the operation can be started by associating the stored value with the magnetic pole position.
[0045]
Therefore, the estimation of the magnetic pole position immediately after power-on may be performed only when the integrated value in the integrator 2157 is no longer stored. For this reason, for example, when the operation of the elevator is stopped, only the main circuit power supply may be cut off, and the integrator 2157 may be used. Further, when the operation is stopped for a long period of time, only the integral value may be stored in the nonvolatile memory, and this value may be used at the next operation.
[0046]
In the present embodiment, the above-described correction of the magnetic pole position may use the magnetic flux signal itself at that time instead of the zero cross point. Also, the calculation of the magnetic pole phase may use the three-phase alternating current and measure the phase from the mutual magnitude of the three voltages.
[0047]
Further, the magnetic pole position estimating unit 215 is configured by a hardware circuit, but may be performed by a microcomputer or the like in a software manner. 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.
[0048]
【The invention's effect】
As described above, according to the present invention, a magnetic pole position detector for detecting a physical absolute magnetic pole position is not used for estimating a magnetic pole position required for controlling a permanent magnet synchronous motor. Since the degree of freedom is increased and the magnetic pole position detector is not used, the maintenance is easy and the cost can be reduced.
[0049]
Further, appropriate control can be performed even when the load is unbalanced or when the load is balanced. Furthermore, the magnetic pole position can be easily estimated at the time of start-up, and the function of correcting the magnetic pole position during operation is provided, so that the magnetic pole position can be estimated with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of an elevator apparatus to which a control device for a permanent magnet synchronous motor according to an embodiment of the present invention is applied.
FIG. 2 is a flowchart illustrating a processing procedure of magnetic pole position estimation immediately after power-on.
FIG. 3 is a diagram for explaining magnetic pole position estimation immediately after power-on.
FIG. 4 is a block diagram showing a configuration of a magnetic pole position estimating unit 215 shown in FIG.
[Explanation of symbols]
21: control device, 211: inverter, 212: speed command, 213: speed control calculator, 214: current control calculator, 215: magnetic pole position estimator, 2151: integrator, 2152: level setter, 2153: adder Reference numeral 2154 Comparator 2155 Speed judging unit 2157 Integrator 218 Starting current command unit 22 Power supply 31 Brake device 51 Permanent magnet synchronous motor 53 Brake drum 54 Encoder

Claims (2)

A permanent magnet type synchronous motor driven by a variable voltage / variable frequency power converter, a mechanical device driven by the synchronous motor, and detecting an induced voltage at the time of rotation of the synchronous motor. Means for estimating the magnetic pole position, detecting the unbalance of the load of the synchronous motor from the output of the load detector of the car, and in the case of an unbalanced load, releasing the brake for stopping and holding the synchronous motor to free In the run, the phase of the magnetic pole is detected from the zero-cross point of the induced voltage generated by the rotation of the synchronous motor. When the motor reaches a predetermined speed, the application of the voltage is stopped, and the mode shifts to the free run. Elevator Starting driven by permanent magnet synchronous motors, characterized in that detecting the magnetic pole position from the point, and controls the synchronous motor. 2. The method according to claim 1, wherein after detecting the magnetic pole position, a low-frequency voltage is applied to the motor, and the motor is moved to the nearest floor without stopping, to start the elevator driven by the permanent magnet synchronous motor.

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