JPS58157395A - Motor pick-up system - Google Patents

Abstract

PURPOSE:To simplify the configuration of a motor-pickup system by obtaining phase, frequency and voltage control signal necessary to pick up by a motor via the software program of a microcomputer. CONSTITUTION:A DC power obtained from a converter 1 is converted by a transistor voltage inverter 2 to variable frequency, variable voltage AC power and supplied to a synchronous motor 3. The gate control signal of the inverter 2 is applied from a microcomputer 5. In order to protect the inverter 2, a shortcircuit current detection signal due to the current detection of a smoothing condenser 6 and a load shortcircuit detection signal due to load current detection are loaded to the microcomputer 5. The frequency of the inverter 2 is set by an operation panel 7.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for picking up a motor after an accident has been resolved in variable speed control of an AC motor using an inverter under pulse width variable W4 (pwM) control.

Conventionally, when operating a synchronous motor or a rust conduction motor at variable speed, a variable frequency inverter is used to drive the staining motor. In variable speed control of electric motors using this inverter, when a failure or instantaneous power outage occurs on the load side such as a short circuit in one of multiple electric motors, the inverter's output voltage 9 frequency and A motor pick-up method has been proposed in which variable speed control is resumed by matching the phase of the rotating motor with inertia.

To realize this motor pickup, a motor frequency detection means is required, and an inverter pulse width modulation (
When using PWM (PWM) control, a phase measuring device or comparator is required to ensure an error range of ±5 degrees in electrical angle for phase alignment during restart, and an inverter with a motor pick-up function is complicated and expensive. Atsuken.

A microcomputer kW is used in the control center of the inverter of the present invention, and a microcomputer 1 (D7 required phase 1) is used.
It is Kuraguchi's objective to provide a motor pick-up system that can simplify the device configuration by obtaining frequency and voltage control signals.

FIG. 1 is a diagram for explaining one embodiment of the present invention.
This is an I-composition diagram. The DC power obtained from the converter 1 is converted to variable frequency, variable voltage AC power by the purple transistor voltage type inverter 2 and is then used as a synchronous motor (or electric motor).
3 to drive the load 4 of the electric motor 3 to the set speed.

The gate control unit v#'i of the inverter 2 is supplied from the microcomputer 5, and depending on the control method of the inverter 2, the voltage control signal of the converter l is also supplied from the microcomputer 5. At the ninth stage of protection of the inverter 2, a short circuit current detection signal obtained by detecting the current of the smoothing capacitor 6 and a load short circuit detection signal obtained by detecting the load current are taken into the microcomputer 5. These signals are sent to the 7microcomputer 6
Inverter interface b, seven through pass line 5. guided by.

The frequency setting of the inverter 2 is set by the setting device provided on the operation panel 7, and this setting signal is passed through the I10 interface 5s k for the operation panel to the pass line 5. guided by.

ROM of microcomputer 5 5. A software program for controlling the Nike inverter is stored in RAM5.
, stores analog and digital signal data from the inverter 2, etc., and stores data for calculation.
At 5°, these data signals provide an inverter output control signal in accordance with the Glogzum.

The primary frequency open-loop control of II, motive 3 and load 4 are performed by the inverter on the microcomputer.
In a closed-loop control trap using the rotation speed detection signal of
Inverter 2 is protected by cutting off gate control signal 4ijr.

After that, the microcomputer confirmed from the induced voltage of the accident-resolved all-electric motor 8 after disconnecting the accident load was found at the motor pickup station 1! to go into.

First, to set the inverter output frequency when picking up the motor, the induced voltage (U, V +
The detection signal of the U phase of the W phase) is captured by the timing signal canter 7 ace b with a phase angle of 0 degrees, and this signal k is used as an interrupt trigger signal to the CPU 5 for one cycle of the timing signal. The frequency setting value is obtained by the basic tarok counting of the computer 5. In addition, the inverter output voltage setting when picking up the motor is
Interface b
The voltage setting value is obtained by converting it into digital data using an analog-to-digital converter.

Next, PW according to the set inverter output voltage and frequency
For M control, in order to pick up a motor that matches the rotational phase of the motor 8 and the output phase of the inverter 2 within ±6 degrees, the microcomputer 5 extracts the phase angle corresponding to the output frequency using a phase angle table, and calculates the induction of the motor. The phase of the voltage detection signal is matched and the inverter operation is fully restarted. This will be explained below.

The ROM 51 of the microcomputer 5 is previously equipped with a phase angle tilt pull in addition to a 10-gram source.

As shown in Figure 2, this phase angle table is based on the rotation speed range (frequency range) of the variable speed motor determined by the specifications.
Pickup phases ♂ and .about.6-3 are set corresponding to frequencies f and .about.f knee % determined by division, respectively. This phase angle 0e~6-1 corresponds to the frequency f, ~fn-10 high,
The electrical angle difference varies depending on the low frequency, and the higher the frequency, the smaller the phase angle becomes. This phase angle -6~6-
8 is set as a phase shift time corresponding to the phase angle, and is further set to include a delay time to be described later.

The microcombiner 5 successively generates a pick-up phase angle akle corresponding to the frequency fk from the above-mentioned phase angle table and the pick-up inverter frequency, and this phase angle - includes a set value for restarting the inverter operation along with another voltage 1 frequency. be done. Inverter operation restart control start timing #'i As shown in Figure 8, the electrical angle of the motor induced voltage U phase detection signal is 0.
degree (A0 point), and at this timing the CPU
5. starts inverter operation gain/opening control, and inverter 2
The point where the motor 8 and the motor 8 are actually connected is at one point in Figure 8. This delay time Td is induced by the software processing delay time by the CPU 5s and the delay time of the filter which becomes the hardware. It is a set value that includes. This delay time Tdt - including phase angle 0°~'
From +1-IK, the connection between the inverter 2 and the motor 8 is as follows:
The phase angle at point A8 changes from when the rotation speed is picked up as shown in b).

Due to the inverter operation restart control, the inverter 2 and the motor 8 are connected at point A1 with the set frequency and voltage 2 phase angle, and the inverter and motor are picked up at the same frequency and voltage 1 phase. After starting operation, control is applied to gradually return the frequency, voltage, and voltage to the pre-failure collection values, and normal operation is resumed.

Therefore, according to the present invention, a phase angle that is safe for motor pickup is obtained by software that reads out a phase angle table having a frequency created by dividing the variable frequency range of the controlled motor by 2n and a phase angle table for pickup corresponding to the frequency. determined by
Since the pickup frequency and voltage are determined by software from the motor's induced voltage detection signal, it can be applied to the PWM control device used as the microcomputer control center, eliminating the need for special hardware for motor pickup. At the same time, it is possible to reduce the cost and size of the control device.Also, by adopting a pickup phase angle table in the microcomputer, the contents of the phase angle table can be changed even when the specifications of the motor to be controlled are changed by using the same software. -f only need to be changed, and it is possible to save time during production and testing, and to shorten test time.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram of a device according to the present invention, FIG. 2 is an explanatory diagram of a phase angle table in the present invention, and FIG. 8 is a waveform diagram for explaining motor pick-up timing in the present invention. 2... Inverter, 3... Electric motor, 4... Load,
5...Microcomputer, 7...Operation panel. 1

Claims (1)

[Claims] In a control device equipped with a microcomputer in the control center for variable speed control of an AC motor by an inverter under pulse width modulation control, the inverter and the AC motor are stopped due to a momentary power outage or load failure. In order to perform motor pick-up control for restarting the motor by the inverter during inertia operation of the motor, the microcomputer determines the inverter output frequency and voltage at the time of motor pick-up from the induced voltage detection signal of the AC motor, and The computer has a phase angle table that defines a frequency determined by dividing the operating frequency range of the AC motor and a phase angle for motor pickup corresponding to the frequency, and calculates the motor from the inverter output frequency at the time of motor pickup and the phase angle table. Motor pickup characterized by determining the phase angle at the time of pickup, setting the inverter output frequency, pressure and phase angle to 1, and restarting the inverter operation control +r at the timing of the electrical angle of 0 degrees of the induced voltage detection signal. method.