A variable frequency soft start and grid-connected control method for permanent magnet synchronous motors

Abstract

The present invention is a permanent magnet synchronous motor frequency conversion soft start and grid-connected control method. First, the voltage and current sampling module samples the motor current and the three-phase voltage of the power grid to generate the amplitude, phase and frequency information of the three-phase voltage of the power grid; the motor speed position is sampled The module samples the position and speed of the motor, the given speed and speed pass through the speed PI regulator module, the motor current signal passes through the coordinate transformation module, the current PI regulator module, the voltage feedforward module, and the voltage argument transformation module to obtain the modulus and angle, and obtain The initial position, duty cycle and frequency information are sent to the FPGA to send SVPWM pulse electrical signals, which are converted into optical signals to drive the IGBT of the frequency converter, and the permanent magnet synchronous motor rotates to realize the soft start of the frequency conversion; finally, the DSP monitors and determines the frequency converter and the power grid in real time Whether the amplitude, phase, and frequency of the three-phase voltage meet the grid-connected switching conditions; solve the soft start of the permanent magnet synchronous motor, and the problem of large inrush current when the permanent magnet synchronous motor switches from frequency conversion to power frequency.

Description

Technical field [0001] The invention belongs to the field of permanent magnet synchronous motor soft start and synchronous switching, and specifically relates to a permanent magnet synchronous motor variable frequency soft start and grid connection control method. Background technique [0002] There are a large number of production machinery in industrial and agricultural production that require continuous operation in one direction at a constant speed. Most of these machinery were driven by three-phase or single-phase asynchronous motors in the past. Asynchronous motors have low efficiency, low power factor, large losses, and soft mechanical characteristics during the starting process, so a lot of energy is wasted in production. In the current situation of increasingly tight energy and serious environmental pollution, energy conservation and emission reduction are particularly important. The installed capacity of electric motors in my country has reached more than 580 million k...

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem of direct start-up of permanent magnet synchronous motors and the problem of large impact current generated by permanent magnet synchronous switching from frequency conversion to power frequency synchronous switching, the present invention proposes a variable frequency soft start and grid-connected control method for permanent magnet synchronous motors

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