Capacitor commutation-based active-shutdown DC solid-state circuit breaker and control method

Abstract

The invention belongs to the field of DC solid-state circuit breakers, and specifically relates to an active-shutoff DC solid-state circuit breaker and method based on capacitor commutation, aiming to solve how to reduce the loss of DC solid-state circuit breakers and realize The problem of reliable active shutdown. The present invention includes: a controller for detecting current and generating a corresponding on-off driving signal of a switch; m , Snubber switch S 1 , Snubber switch S 2 , discharge branch switch S 3 and discharge branch switch S 4 The conduction or disconnection of the system to realize the steady state of the system, the transient state of the fault disconnection, the driver of the active shutdown isolation transient state; the pre-charge capacitor C that provides the discharge current 1 and C 2 ; The first buffer absorption branch and the second buffer absorption branch for current buffering and absorption after the charging process is completed. The invention realizes the loss reduction of the DC solid-state circuit breaker and reliable fault disconnection and active shutdown isolation in medium and low voltage disconnection occasions.

Description

technical field [0001] The invention belongs to the field of DC solid-state circuit breakers, and in particular relates to an active-shutoff DC solid-state circuit breaker and method based on capacitive commutation. Background technique [0002] In recent years, thanks to the rapid development of power electronics technology, DC transmission technology has become a hot spot in research and engineering applications due to its advantages of high efficiency and low loss. However, the fault current in the DC system does not have a natural zero-crossing point, so it cannot be disconnected in the same way as the AC system; at the same time, the low system impedance of the DC system means that the fault current has a high rate of rise. The above factors make the fault disconnection of the DC system a constraint A major problem in the development of direct current transmission. The solid state circuit breaker (Solid State Circuit Breaker, SSCB) based on high-power power electronic ...

AI Technical Summary

Problems solved by technology

[0004] However, due to the large conduction loss of power electronic devices, solid-state circuit breakers are currently mainly used in low-voltage, low-current breaking occasions, and the application scenarios of solid-state circuit breakers need to be expanded.

The application of low-loss semi-controlled devices such as thyristors is an effective way to improve the performance of solid-state circuit breakers. However, there is an obvious shortcoming in the above-mentioned topology. If active power-off maintenance is required, the normal side of the system needs to withstand twice the system voltage, which will affect the normal operation of the system. work has a destructive impact

In addition, the existing technology cannot take into account the excellent performance requirements and functional integration requirements of solid-state circuit breakers, and further improvement is needed

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