JP2005162462A - Control device of elevator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device of an elevator, obtaining a coefficient of correction of a current conversion gain without fine adjustment of voltage in the case where there is a difference in resistance value between alternating current motor coils or in the case where there is an error between a voltage command and output voltage of an inverter. <P>SOLUTION: This control device of an elevator includes: a speed control device; a current control device 17 for giving a voltage command according to a command value, a speed feedback signal and a current feedback signal; an inverter 4 for driving an AC motor according to a voltage command; a current detector 10 for feedbacking an electric current flowing through the motor; a correction computing device 21 for multiplying the output of the current detector by a coefficient of correction to correct a detection value; and a current sensor gain coefficient calculating device 22 for calculating a coefficient of correction, wherein a car and a balancing weight are elevated. A control electric angular phase of the inverter is fixed to a designated value, and a predetermined torque current command is given to let a predetermined DC current flow between the two phases of the motor, and a coefficient of correction is calculated by the current sensor gain coefficient calculating device. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an elevator control device.

In a general three-phase AC motor control device, if there is an imbalance in the conversion gains of the current detector and the A / D converter, an imbalance occurs between the phases of the three-phase current flowing through the motor. In some cases, pulsation occurred in the torque.
In order to solve this problem, according to the conventional control device for a three-phase AC motor, one of the current detection values of each phase of the three-phase AC motor is set as a reference phase, and this reference phase and the other one phase A predetermined direct current flows through only the winding of the current, and a ratio of the current detection gain of the reference phase and the current detection gain of the other one phase is obtained from each current detection value at this time. In addition, a predetermined direct current flows only through the reference phase and another other one-phase conductor, and from the current detection value at this time, the current detection gain of the reference phase and another one-phase current detection gain Find the ratio. During operation of an electric motor, a correction coefficient of a current detection value is calculated using the obtained conversion gain ratio, and the current detection gain imbalance is corrected by multiplying this coefficient (for example, see Patent Document 1).

JP-A-5-91780

  By the way, in the conventional control device, for example, when obtaining the correction coefficient of the V-phase current conversion gain, the input to the PWM signal generator is performed so that a predetermined direct current flows only through the U-phase and V-phase windings. It is supposed to be set. However, if there is a difference in the resistance values of the U-phase and V-phase windings, or if there is an error between the voltage command and the voltage output from the inverter device, the voltage having the same magnitude but the opposite sign Even if is added between the U phase and V phase of the AC motor, the current flowing in the W phase cannot be reduced to 0. To reduce the current flowing in the W phase to 0, PWM is performed while observing the W phase current. There was a problem that the voltage command to the signal generator had to be finely adjusted, and the work was complicated.

  The present invention has been made to solve the above-described problems, and there is an error between the voltage command and the voltage output from the inverter device when there is a difference in resistance value between windings of the AC motor. An object of the present invention is to provide an elevator control device that can obtain a correction coefficient of a current conversion gain without finely adjusting a voltage.

  An elevator control device according to the present invention includes: a speed control device that generates a torque command value from a speed command value and a speed feedback signal; a current control device that generates a voltage command from the torque command value, the speed feedback signal, and a current feedback signal; An inverter that drives the AC motor according to the voltage command, a current detector that feeds back the current flowing through the AC motor, a correction calculator that corrects the detected current value by multiplying the output of the current detector by a correction coefficient, A current sensor gain coefficient calculator for calculating a correction coefficient, and controlling the AC motor to raise and lower the car and the counterweight, the control electrical angle phase of the inverter is fixed to a predetermined value, By giving a torque current command, a predetermined DC current is caused to flow between the two phases of the AC motor, and a correction factor is calculated by a current sensor gain coefficient calculator.

  In the elevator control apparatus according to the present invention, the correction arithmetic unit for correcting the detected current value by multiplying the output of the current detector by the correction coefficient, and the control electrical angle phase of the inverter are fixed, and a predetermined torque current command is given. A current sensor gain coefficient calculator that measures and calculates the correction coefficient, and when the current sensor gain coefficient calculator determines the correction coefficient for a phase, in addition to the current detection values for that phase and the reference phase, Since the calculation is also performed using the detected current value, it is possible to easily allow a direct current to flow between the two phases of the AC motor. In addition, the correction coefficient of the current conversion gain can be obtained without finely adjusting the voltage.

Embodiment 1 FIG.
1 is a block circuit diagram showing a configuration of an elevator control apparatus according to Embodiment 1 of the present invention.
In FIG. 1, 1 is a three-phase AC power source, 2 is a converter, 3 is a capacitor, 4 is an inverter, 5 is an AC motor, 10a is a current detector for detecting a current flowing in a U-phase winding, and 10b is a V-phase. A current detector that detects a current flowing through the winding, 10c is a current detector that detects a current flowing through the W-phase winding, 11 is an encoder that outputs a speed feedback signal, 12 is a differentiator, and 13a is a speed command value. Feedback speed adders for comparing and calculating the speed feedback signal, 13b and 13c are feedback current adders, 14 is a current command generator, and 15a is a digital converter for the current flowing in the U-phase winding detected by the current detector 10a. / D converter, 15b is an A / D converter that digitally converts the current flowing in the V-phase winding detected by the current detector 10b, and 15c is the W detected by the current detector 10c. A / D converter for digitally converting the current flowing in the winding of the coil, 16 is a three-phase two-phase coordinate converter, 17a and 17b are current controllers, 18 is a two-phase three-phase coordinate converter, and 19 is a PWM signal generator , 20 is a gate drive circuit, 21a is a V-phase correction coefficient that multiplies the correction coefficient to correct the current detection value, 21b is a W-phase correction coefficient that similarly multiplies the correction coefficient to correct the current detection value, and 22 is from the outside. A current sensor gain coefficient calculator that creates a predetermined torque current command and a zero command of reactive current according to a current sensor gain coefficient correction command that is a signal of This switch switches the torque current command and the reactive current command during operation to the predetermined torque current command and the reactive current 0 command. In the figure, 24 is an elevator hoisting machine, 25 is an elevator car, and 26 is a counterweight.

The specific operation of the elevator control apparatus according to the first embodiment of the present invention will be described.
Here, the relationship between the digital signal values Xu, Xv, Xw of the current flowing in each phase of the AC motor and the current conversion gains Kv, Kw will be described. First, in a general three-phase AC motor in which the neutral point is not connected to the outside, the equation (1) is established for the currents Iu, Iv, and Iw of each phase.
Iu + Iv + Iw = 0 (1)
When the current value of each phase is digitally converted, an error due to detection / conversion occurs as described above. For example, with reference to the U-phase digital conversion gain, a correction coefficient for the V-phase and W-phase current conversion gains is used as a reference. That is, assuming that the ratio of the current gain of the V phase to the U phase and the ratio of the current gain of the W phase to the U phase are Kv and Kw, Equation (2) is established between the signal values after digital conversion.
Xu + Kv · Xv + Kw · Xw = 0 (2),
From the above equation (2), Kv and Kw are obtained so that a digital conversion value of current, for example, Xu becomes zero. In this case, unlike the conventional example, there is no need to allow a predetermined direct current to flow only through the U-phase and V-phase windings, so there is no need to finely adjust the voltage command to the PWM signal generator 19.
In FIG. 1, a current sensor gain coefficient calculator 22 generates a predetermined torque current command and a reactive current zero command in accordance with a current sensor gain coefficient correction command which is an external signal. Next, the torque current command and the reactive current command during normal operation are switched to the predetermined torque current command and the reactive current 0 command by the switch 23 in accordance with a current sensor gain correction coefficient command that is an external signal. In addition, the electrical angle of the rotor used during normal operation is switched to the control electrical angle phase of the inverter created in the following manner by the switch 23 using a current sensor gain coefficient correction command, which is an external signal, as a trigger. In this state, the current sensor gain coefficient is calculated by the current sensor gain coefficient calculator 22. The control electrical angle phase of the inverter when giving a predetermined torque current command is described below.

  FIG. 2 shows the relationship between the rotor electrical angle and each phase current when d-axis current zero control, which is often used in the control of a synchronous motor, is performed. As can be seen from FIG. 2, near the timing 1 (electrical angle of 60 °), current flows in the U phase and V phase, and almost no current flows in the W phase, and near the timing 2 (electrical angle of 120 °). Then, it can be seen that current flows in the U phase and the W phase, and almost no current flows in the V phase. When the electrical angle of the rotor is fixed at these timings and a predetermined torque current command is given, a direct current having the opposite sign flows in the two phases of the AC motor, and almost no current flows in the remaining one phase. It becomes possible. In the above description, the timing for detecting each phase current is set to two electrical angles of 60 ° and 120 °. However, the same timing appears at electrical angles of 240 ° and 300 °, and the latter timing is also effective. Needless to say, is the same.

Embodiment 2. FIG.
A specific operation of the elevator control apparatus according to Embodiment 2 of the present invention will be described. FIG. 3 is a flowchart showing the operation of the current sensor gain coefficient calculator when obtaining the current conversion gain correction coefficient in the elevator control apparatus according to Embodiment 2 of the present invention.
First, in the first step S101, the counter n for repeated calculation is set to 0 in the initial value setting, and the initial value Kvw (0) of the correction coefficient Kvw (n) in the calculation process is set to 1. Since the present invention calculates Kv and Kw by repeated calculation, the above setting is required.
Next, in the second step S102, a predetermined direct current is passed through the U-phase and V-phase windings in the same manner as in the first embodiment. At this time, almost no current flows in the W phase.
Next, in the third step S103, the currents flowing through the U-phase, V-phase, and W-phase windings are detected by the current detectors 10a, 10b, and 10c, and converted into digital signals by the A / D converters 15a, 15b, and 15c. The digital signal values are Xu1 (U phase), Xv1 (V phase), and Xw1 (W phase), respectively. Kvw (n) calculated by the previous calculation is reflected in the above equation (2), and Kw (n) is changed to calculate Kv (n) when Xw1 = 0. However, in the first calculation, since the previous value does not exist, Kvw (0) = 1 is used.
Next, in the fourth step S104, a predetermined direct current is passed through the V-phase and W-phase windings in the same manner as in the first embodiment. At this time, almost no current flows in the U phase.
Next, in the fifth step S105, Kv (n) is calculated by reflecting Kw (n) obtained in the third step S103 and changing Kv (n) so that Xu2 = 0.
Next, in a sixth step S106, a predetermined direct current is passed through the U-phase and W-phase windings in the same manner as in the first embodiment. At this time, almost no current flows in the V phase.
Next, in the seventh step S107, Kvw (n) that satisfies Xv3 = 0 is calculated by reflecting Kv (n) obtained in the fifth step S105 and changing Kvw (n).
Next, in the eighth step S108, differences Kv (n) −Kv (n−1) and Kw (n) −Kw (n−1) between correction coefficients in the previous and current calculations are calculated, and the difference is calculated. If it is larger than the predetermined allowable value e, the calculation is performed again. Finally, in step S109, the corrected correction coefficients Kv (n) and Kw (n) are stored as final correction coefficients Kv and Kw.

  When using the current detector, for example, as shown in Japanese Patent No. 2687062 “Control Device for Electric Motor”, an alternating current that decays in time before use is passed, The demagnetizing operation for removing the hysteresis of the magnetic circuit is performed, and the detection output in the state of current 0 after the degaussing operation is stored, and this value is subtracted from the detection value at the time of actual measurement as an offset value for current detection. It is common to use a current detection value. These operations are not described in the above-described embodiment of the present invention. However, by performing these operations before measuring the correction coefficient of the current detection gain, the current detection is performed also in the present invention. Needless to say, the accuracy of the correction coefficient of the current detection gain can be improved. Furthermore, it is a matter of course that the influence of noise can be reduced by processing the current detection value through an appropriate low-pass filter.

It is a block circuit diagram which shows the structure of the control apparatus of the elevator in Embodiment 1 of this invention. It is a figure which shows the relationship between a rotor electrical angle and each phase electric current in the case of performing d-axis current zero control often used by control of a normal synchronous motor. It is a flowchart which shows operation | movement of the current sensor gain coefficient calculator at the time of calculating | requiring the correction coefficient of current conversion gain in the elevator control apparatus in Embodiment 2 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Three-phase alternating current power supply 2 Converter 3 Capacitor 4 Inverter 5 AC motor 10 Current detector 11 Encoder 12 Differentiator 13a Feedback speed adder 13b, 13c Feedback current adder 14 Current command generator 15 A / D converter 16 3 phase 2 Phase coordinate converters 17a, 17b Current controller 18 2-phase 3-phase coordinate converter 19 PWM signal generator,
20 Gate drive circuit 21a V phase correction coefficient 21b W phase correction coefficient 22 Current sensor gain coefficient calculator 23 Switch 24 Elevator hoist 25 Elevator car 26 Counterweight

Claims (2)

A speed control device that generates a torque command value from the speed command value and the speed feedback signal;
A current control device that generates a voltage command from a torque command value, a speed feedback signal, and a current feedback signal;
An inverter that drives an AC motor according to the voltage command;
A current detector for returning the current flowing through the AC motor;
A correction calculator for correcting the detected current value by multiplying the output of the current detector by a correction coefficient;
A current sensor gain coefficient calculator for calculating a correction coefficient,
In the elevator control device that controls the AC motor to raise and lower the car and the counterweight,
The control electrical angle phase of the inverter is fixed to a predetermined value, and a predetermined torque current command is given to cause a predetermined DC current to flow between the two phases of the AC motor, and the current sensor gain coefficient calculator calculates the correction coefficient. An elevator control device.   2. The elevator coefficient according to claim 1, wherein when a current flows through the AC motor, the correction coefficient value is changed, and a correction coefficient is calculated so that one-phase current among the digital conversion values of the current becomes zero. Control device.

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