Current-limiting solid-state circuit breaker for actively suppressing overvoltage and control method thereof

Abstract

The invention relates to a current-limiting solid-state circuit breaker capable of actively suppressing overvoltage and a control method thereof. The circuit structure of the device is shown in a dotted frame in figure and comprises a master switching circuit, a follow current circuit and a control system, wherein the master switching circuit comprises a Q1 and a Q2, the follow current circuit comprises a Q3, a Q4 and a Q5, the master switching circuit is formed by reversely connecting two field effect transistors (MOSFET, MOS transistors) Q1 and Q2, an output end of the master switching circuit is connected with one end of the follow current circuit, the control system detects the input voltage of the solid-state circuit breaker and the current of the master switching circuit and controls the MOS transistors of the master switching circuit and the follow current circuit according to the input voltage and the current, the control system takes protective measure when the current of a main loop is detected to exceed a rated value or a current limiting value, the Q3 or the Q4 of a follow current branch is firstly conducted according to the directions of the current and the input voltage, the switching circuit is then cut off, higher voltage (Ldi / dt) caused by a stray inductor L in a power supply circuit during switching off the Q1 and the Q2 is prevented from being applied to the two ends of the MOS transistors of the master switching circuit, and the voltage stress during switching off the Q1 and the Q2 can be greatly reduced. Except for actively preventing overvoltage, compared with other solid-state circuit breaker, the current-limiting solid-state circuit breaker has the advantages that the MOSFET switching tubes are adopted, the structure is simple, the current-limiting solid-state circuit breaker is convenient to drive and easy to expand capacity in parallel, and the conduction loss is reduced.

Description

technical field [0001] The invention belongs to the technical field of power system fault protection, in particular to a topology of a current-limiting solid-state circuit breaker for actively suppressing overvoltage and a control method thereof. Background technique [0002] As an important link in the transmission line of the power grid, the circuit breaker is an important control and protection device, and its performance directly affects the normal operation of the power grid. It is stable and has a strong load capacity, but when the load is disconnected, an arc is often generated, the contacts are easily burned, and the breaking time is long, which is difficult to meet the quick action requirements of some power users for fault current breaking. [0003] Compared with the traditional mechanical circuit breaker, the solid-state circuit breaker based on power electronic devices has the remarkable structural features of no contact, no need for arc extinguishing and other m...

AI Technical Summary

Problems solved by technology

At present, the overvoltage protection in solid-state circuit breakers mainly relies on two methods: resistance-capacitance snubber circuit and zinc oxide lightning rod. These two methods are passive protection against overvoltage, and do not fundamentally eliminate the cause of overvoltage.

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