Implementing Diode-Free MOV-RCV Snubber Based DC Solid-State Circuit Breakers

Abstract

This article presents a diode-free metal-oxide-varistor (MOV) resistor-capacitor-varistor (RCV) snubber based solid-state circuit breaker. It prevents voltage overshoot and ensures a smooth turn-off voltage slew rate. Compared with a conventional MOV resistor-capacitor-diode (MOV-RCD) circuit, the MOV-RCV snubber adopts a low-voltage MOV (LMOV) to replace a high-power diode to reduce cost, and there is no continuous voltage stress across the LMOV. The working principle and design method in the MOV-RCV circuit are presented through LTspice simulation. Its effectiveness is further validated by 400 V/140 A interruption experiments with different LMOVs. The experimental results illustrate a successful interruption process, and the maximum turn-off dv/dt is limited at 7.9 V/ns. In addition, the proposed MOV-RCV snubber achieves 31% cost saving compared with a MOV-RCD based counterpart.