A Thyristor Controlled Bidirectional DC Solid State Circuit Breaker for Residential Microgrids

Buildings consume roughly 40% of total global energy out of which, residential buildings account for three-quarters of total energy consumption in the building sector, and there is significant room for improvement in energy efficiency. Residential dc microgrid is a promising technology that aims to ease the transition to energy-efficient homes and provide a simple, highly flexible integration of renewable energy sources, storage, and loads. However, the dc systems have no natural current zero crossing points and lack proper standards to safeguard residential dc systems against faults. Furthermore, because of the low inertia, the fault current may surge to greater magnitudes quickly, necessitating the adoption of solid-state circuit breakers (SSCBs), which are fast and reliable protection devices. This paper introduces a thyristor-based bidirectional SSCB wherein the fault current interruption is achieved by adopting coupled inductors. A detailed operation and analysis of the proposed SSCB is presented. The paper also presents an experimental validation of the proposed SSCB at a dc system rating of 250 V and 10 A (20 A fault current) and 350 V at 20 A (25 A fault current).

I. Introduction

Buildings consume a significant amount of energy and need to be managed effectively to optimize the energy consumption. There is an urge for the transition to a decarbonized energy system by 2050 by enabling high-performing, flexible, energy-efficient residential and commercial buildings. Residential dc microgrids and nanogrids are a new technology that aims to promote the shift to energy-efficient buildings. Higher efficiency at the same voltage levels, no requirement for reactive power correction or frequency synchronization, and simplicity in integrating renewable energy sources are the key advantages of dc microgrid systems. The dc systems can be interconnected with a variety of renewable energy sources and energy storage systems from the power supply side, and multiple dc loads including data centers, electric vehicle charging stations, railroads, residential loads, and industrial loads, also can be supplied simultaneously from the load side. Thanks to the dc systems for their improved reliability and reduced installation cost as it eliminates intermediate stage ac/dc converters at the load end [1]–[7].