JPH02280688A - Inverter device - Google Patents

Abstract

PURPOSE:To permit the setting of an operating parameter even when no data is prepared by a method wherein the non-vector control of an induction motor is effected and the operating parameter is computed from various feedback and during the non-vector control and stored, CONSTITUTION:The primary voltage and the primary current of an induction motor 12 are detected by a transformer 6 and a current transformer 5 and are fed back to a vector controller 20 through a signal converter 8. The CPU of the vector controller 20 operates necessary operating parameters, such as the motor constant of the induction motor, the GD<2> of a load 13, a resistance torque and the like, based on the feedback primary voltage, the primary current, the characteristic formula of the set frequency induction motor 12 and the like and stores them in a memory, then, the vector controller 20 is operated by switching a changeover switch 30 into the side of the controller 20 to effect the fine regulation of the operating parameters. According to this method, the operating parameters may be set even when the operating parameters such as the motor constant and the like are not clear previously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field] The present invention relates to setting control parameters of an inverter device that performs vector control of an induction motor.

[Prior Art] Figure 2 is a circuit diagram showing the configuration of a conventional variable voltage variable frequency (VVVF) inverter device for controlling an induction motor. Converter, 3 is a capacitor, 4 is a transistor type inverter, and 2 to 4 constitute a main circuit of the inverter device.

A three-phase induction motor 13 supplied with power from this main circuit is a fan 12 which is a motor load. 5 is a current transformer CT, and 6 is a transformer PT, each of which detects the output current and voltage of the main circuit, and these outputs are converted into a signal level by a signal converter 8. 9 is a PWM circuit, which generates a PWM signal by receiving a frequency command and a voltage command from a voltage/frequency control circuit 10 that takes in a set frequency and sends out a voltage/frequency command that makes the voltage/frequency ratio constant. The signal is then sent to the base drive circuit 7. 11 is a frequency setter that sends out a set frequency.

FIG. 3 shows an inverter device that performs vector control of an induction motor, and the vector control section 20 is a calculation processing section (
CPU) 201, memory 202, A/D conversion unit 203,
It has an output port 204, an analog input port 205, a calculation parameter setting switch 206, an input port 207, a data read port 208, and a numeric display section 209.

When variable speed control of an induction motor is performed using an inverter device, a vector control method is adopted to control the instantaneous values of voltage and current supplied to the induction motor as a means of improving acceleration/deceleration characteristics, current limiting characteristics, torque control characteristics, etc. It is now possible to do so.

This vector control performs arithmetic control using the DC flow with the rotating magnetic field axis of the induction motor as the reference coordinate, and converts the coordinates to an AC flow. Since it is essential to set a large number of calculation parameters such as motor constants, etc.) and various load characteristics (CD'', etc.), the inverter control device is usually configured using a microcomputer CPU, as shown in Figure 2. and set these calculation parameters using setting switch 2.
06 and set them one by one in the memory 202 while looking at the display on the numeric display section 209.

In the non-hector control shown in FIG. 2, it is not necessary to set the above calculation parameters.

[Problem to be solved by the invention]

In this way, when performing vector control of the induction motor 12, it is necessary to set calculation parameters, which requires time and effort.
If No. 2 is an old existing installation, its design data may have disappeared and there may be no clue as to the motor constants.

This invention was made to solve the above problem.
To provide an inverter device that can reduce the effort and time required for setting calculation parameters compared to conventional methods, and also allows the setting of calculation parameters such as motor constants even when these calculation parameters are unknown. With the goal.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a non-vector control section in addition to the vector control section, which is switchable with the control section, and the vector control section is configured to control the inverter by the non-vector control section. The configuration is such that various quantities fed back during operation are taken in, calculation parameters are calculated, and stored.

(Function) In this invention, by sending voltage and frequency commands from the non-vector control unit to operate the inverter main circuit,
A vector control unit calculates and sets required calculation parameters such as motor constants from the actual primary current and voltage values of the induction motor.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

In the first time, 30 is a switching switch, and PWM
The output of the voltage/frequency control circuit IO and the output of the vector control section 20 are selectively inputted to the control circuit 9.

In this configuration, when setting calculation parameters such as motor constants, the changeover switch 30 is switched to the voltage/frequency control circuit 10 side, and the inverter device is operated at the rated frequency of the induction motor 12 and an arbitrary frequency. The primary voltage and primary current of the induction motor 12 are transmitted through a transformer 6 and a current transformer 5.
is detected by the vector controller 2o through the signal converter 8.
will be given feedback. The vector control unit 2o uses the fed back primary voltage/current and frequency setting il.
The motor constant of the induction motor 12, CD2 of the load 13,
The CPU 201 calculates necessary calculation parameters such as reaction torque.
The calculation is performed and stored in the memory 202, and then the selector switch 3° is switched to the vector control unit 20 side and the operation is performed to finely adjust the calculation variables.

At the time of vector control, the changeover switch 3o is changed and the vector control unit 20 storing the above calculation parameters is set to PW.
Connect to M circuit 9.

Note that in the above embodiment, the CPU 2 of the vector control unit 20
Although the calculation parameters are calculated in step 01, a transmission means may be provided to transmit the feedback quantities to an off-line personal computer to perform a detailed simulation and evaluate the calculation parameters.

In the above embodiment, the case where the coordinate transformation is performed by calculation has been described, but the present invention can of course be applied to vector control having a device for detecting the magnetic flux phase.

(Effects of the Invention) As explained above, the present invention has a configuration in which the induction motor is controlled in a non-hectoral manner, and calculation parameters are calculated and stored from various quantities fed back at this time.
In addition to making it easier to set calculation parameters than before, such as being able to set calculation parameters on-site without data preparation, Since the motor constant can be detected even when the constant is unknown, vector control of the induction motor can be performed.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention, and FIGS. 2 and 3 are circuit diagrams showing a conventional control device for an inverter device. In the figure, 10-voltage/frequency control surface, 20-vector control section, 3o-switching switch. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] In an inverter device that controls an induction motor by calculating a control amount using calculation parameters including preset motor constants, the control device can be switched with the vector control section that performs the above calculations in addition to the vector control section that performs the above calculations. The method further includes a non-vector control section that performs constant voltage/frequency control, and wherein the vector control section calculates and stores the calculation parameters based on various quantities fed back during inverter operation by the non-vector control section. Features of the inverter device.