Two-level circuit board for achieving permanent magnet synchronous motor frequency conversion soft start and grid-connected control

Abstract

The invention discloses a two-level circuit board for achieving permanent magnet synchronous motor frequency conversion soft start and grid-connected control. The two-level circuit board comprises a voltage-current sampling module and a motor conversion position sampling module, wherein the voltage-current sampling module and the motor conversion position sampling module are used for respectively acquiring grid voltage, motor current and motor speed, used for converting the parameters into digital signals, used for transmitting the signals to a DSP (Digital Signal Processor), transmitting 6 paths of PWM (Pulse Width Modulation) electric signals through synergistic treatment of the DSP and FPGA (Field Programmable Gate Array), and used for driving 6 IGBTs (Insulated Gate Bipolar Transistors) of a voltage type two-level frequency converter to be powered on and off so as to achieve soft start of a permanent magnet synchronous motor; meanwhile, the DSP compares the grid voltage which is sampled in real time with three-phase voltage output from the frequency converter; and when a synchronous switching condition is met, the DSP transmits a switching control signal and feeds into a relay driving module to ignite the solenoid of a three-phase alternating current contactor, achieve on-off of the three-phase alternating current contactor, and finally achieve synchronous switching of frequency conversion of the permanent magnet synchronous motor to grid-connected frequency current impact. The problems of soft start of the permanent magnet synchronous motor and large current impact when switching from frequency conversion to working frequency of the permanent magnet synchronous motor can be solved.

Description

technical field [0001] The invention relates to the field of variable frequency soft start and synchronous switching of permanent magnet synchronous motors, in particular to a two-level circuit board for realizing variable frequency soft start and grid-connected control of permanent magnet synchronous motors. Background technique [0002] Due to the difficulty of direct starting of high-power permanent magnet synchronous motors, hard starting will bring a large inrush current to damage the structure of the motor body, and will also affect the power grid and other power supply equipment; with the rapid development of power electronic devices, the price continues to rise The reduction has promoted the development of variable frequency soft start and synchronous switching of large-capacity permanent magnet synchronous motors. By investing in a frequency converter, the soft start of multiple permanent magnet synchronous motors and the frequency conversion speed regulation of one...

AI Technical Summary

Problems solved by technology

[0005] In order to solve the soft start of permanent magnet synchronous motor and the problem of large impact current when permanent magnet synchronous motor switches from frequency conversion to power frequency, the present invention provides a two-level circuit board for realizing variable frequency soft start and grid-connected control of permanent magnet synchronous motor

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