Soft power-on rectifier circuit with electrolytic capacitor connected in series with power resistor

Abstract

The invention provides a soft electrification and rectification circuit of an electrolytic capacitor string electrification resistor, and the soft electrification and rectification circuit can be applied to the application field in which AC-DC converters are used as front-end circuits. The soft electrification and rectification circuit comprises a rectification unit, a comparison unit and a drive unit, wherein the rectification unit is used for completing a single-phase rectification process; the comparison unit is used for judging a DC circuit current-limiting resistor resection condition; the drive unit is used for completing soft electrification resistor resection control; and the rectification unit comprises four power diodes PD1-PD4, one power MOSFET PS1, one thermistor PTC1, one electrolytic capacitor EC1, and three divider resistors R1-R3. The soft electrification and rectification circuit of the electrolytic capacitor string electrification resistor is capable of realizing soft electrification and single-phase rectification at the same time, and has the advantages of being simple in circuit, complete in function and low in cost.

Description

technical field [0001] The invention relates to a single-phase rectifier circuit in the technical field of power electronic conversion, in particular to a soft power-on rectifier circuit in which electrolytic capacitors are connected in series with electrical resistors. Background technique [0002] For power electronic conversion equipment powered by AC power with a diode rectifier circuit, such as frequency converters and frequency conversion household appliances, the issue of soft power-on needs to be considered. Otherwise, because the initial electrolytic capacitor voltage is zero, the power electronic conversion device will have an overcurrent fault during the power-on stage, resulting in overvoltage breakdown of the subsequent stage converter and air switch action. [0003] Among the commonly used power-on current-limiting measures, most of them adopt the method of adding a current-limiting resistor in the AC or DC line, which specifically includes three methods: (1) T...

AI Technical Summary

Problems solved by technology

The problem with the first two methods is: the secondary current impact problem is brought about when the resistance is cut off

The problem with the latter method is that it is only suitable for applications with a load power below 200W

For power electronic conversion devices that start and stop frequently, the PTC thermistor will lose its current limiting function due to heat. Work

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