Power-on and braking circuit of frequency conversion drive system

Abstract

The invention discloses a power-on and braking circuit of a variable frequency drive system. The power-on and braking circuit comprises a power-on braking circuit, a rectifying circuit and the drive system. A soft power-on circuit and a braking circuit are combined to form the power-on and braking circuit, the two input ends of the power-on and braking circuit are connected with two output positive electrodes and two output negative electrodes of the rectifying circuit respectively, the two output ends of the power-on and braking circuit are connected with two input positive electrodes and two input negative electrodes of the drive system respectively, the two input ends of the rectifying circuit are connected with a live wire and a null line of a single-phase alternating current power source respectively, and the drive system is a variable frequency speed control system. Soft power-on of a rectifier and rapid braking of a motor can be achieved, power-on currents are small in impact, the reliable braking function is achieved, the circuit structure is simple without manual control, and the power-on and braking circuit is suitable for the variable frequency speed control system adopting the alternating current power source for power supply.

Description

technical field [0001] The invention relates to a device in the field of AC frequency conversion and speed regulation using power electronic conversion technology, in particular to a power-on and braking circuit for a frequency conversion drive system. Background technique [0002] The power-on current limiting circuit and fast braking circuit are important components of the variable frequency drive system, and their application fields include industrial sewing machines, CNC machine tools, etc. [0003] In a large power system, the energy storage capacitor on the output side of the rectifier circuit has a large capacity and its initial voltage is zero, so the energy storage capacitor will cause a high-amplitude inrush current during the power-on stage, causing damage to power devices, pollution Power grid and other adverse consequences, so power-on current limiting measures must be taken. Up to now, the power-on current-limiting circuit has a variety of solutions, including...

AI Technical Summary

Problems solved by technology

This method is complicated to control, high in cost, and the braking energy is consumed inside the motor, so it is not suitable for frequent braking applications

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