Motor grid-connected operation control method and device and grid-connected operation control system

Abstract

The embodiment of the invention provides a motor grid-connected operation control method and device and a grid-connected operation control system.The method comprises the steps that when a first switch, a second switch and a third switch are all in an off state, if a starting-up instruction sent by instruction sending equipment is received, the second switch and the third switch are controlled to be switched on; the method comprises the following steps of: connecting an asynchronous starting permanent magnet synchronous motor and a power grid with a frequency converter; controlling the third switch to be switched off and the first switch to be switched on when the maximum voltage deviation between the power grid and the frequency converter is determined to be smaller than a preset voltage threshold value after the operation frequency of the asynchronous starting permanent magnet synchronous motor is controlled to be the target frequency carried in the rotating speed control instruction based on the frequency converter; and the asynchronous starting permanent magnet synchronous motor is connected into a power grid for operation. According to the invention, grid-connected operation of the motor can be realized through the frequency converter, so that the problems of difficulty in direct grid-connected starting of the motor and unsafety caused by over-torque and low voltage during operation are solved.

Description

technical field [0001] The invention relates to the technical field of motor operation, in particular to a control method and device for grid-connected operation of a motor, and a grid-connected operation control system. Background technique [0002] Asynchronous starting permanent magnet synchronous motors are widely used in grid-connected fixed-speed driving scenarios due to their high efficiency and high power density. In actual operation, the asynchronous start permanent magnet synchronous motor often runs in the way of direct grid connection. However, the excessive starting current of the asynchronous start permanent magnet synchronous motor in the process of direct grid connection will cause the capacity of the power supply transformer to increase and the torque to be excessive. Large, easy to damage couplings and shaft extension keys and other connecting mechanisms, and when driving large inertia loads, the start-up process is long or the synchronization cannot be swi...

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Problems solved by technology

[0003] In view of this, the object of the present invention is to provide a control method, device and grid-connected operation control system for a motor grid-connected operation, so that the asynchronously started permanent magnet synchronous motor can be started by a frequency converter, which overcomes the direct problem of the asynchronously started permanent magnet synchronous motor. Difficulty in grid-connected startup and unsafe problems caused by over-torque and low voltage during operation

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