Method of asynchronously starting electrically-excited synchronous motor by frequency converter

Abstract

The invention discloses a method of asynchronously starting an electrically-excited synchronous motor by a frequency converter. The method comprises steps: (1) a starting signal is sent; (2) rotation speed information is tracked and the frequency converter drives the motor to operate; (3) the actual motor operation rotation speed and the operation frequency are acquired, and whether the operation frequency at the time is larger than an exciting frequency point setting value is judged; (4) asynchronous operation to the exciting frequency point setting value is carried out; (5) stable operation is carried out to wait for exciting; (6) excitation is put in; (7) whether exciting succeeds or not is judged, in the case of success, a step (9) is executed, or otherwise, a step (8) is executed; (8) preparation is made for following re-operation of the frequency converter and the exciting of the motor; and (9) the motor enters a synchronous state, and at the time, the frequency converter drives the motor to synchronously operate to the frequency set by the frequency converter and stabilized to a set frequency, and other speed regulation instructions is waited. The method of the invention has the advantages that the principle is simple; synchronous starting can be quickly realized; and the controllability and the reliability are good.

Description

technical field [0001] The invention mainly relates to the field of motor control methods, in particular to a method for asynchronously starting an electric excitation synchronous motor by a frequency converter. Background technique [0002] There are usually two starting methods for electric excitation synchronous motors based on frequency converters: one is to start the excitation first, and then start synchronously through the frequency converter; the other is to start asynchronously through the frequency converter first, and then pull the excitation into synchronization. [0003] Synchronous start: mainly divided into open-loop synchronous start and closed-loop synchronous start: [0004] Open-loop synchronous starting is to start the motor with VF open-loop control mode. The key is to find out the appropriate stator voltage at different frequency points according to the rotor excitation current during the starting process, which is equivalent to finding a nonlinear curv...

AI Technical Summary

Problems solved by technology

In some high-power occasions, the moment of inertia of the system is very large, and it takes nearly half an hour to wait for the motor to stop completely after the excitation fails, resulting in too much waiting time for the debugging process, which is time-consuming

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