Design and Analysis of a Bi-Directional Solid-State Battery Protection System for Solid-State Transformer Based Grid Supporting Ev Charging Systems

Solid-State Transformers (SSTs) offer higher power density and high-frequency galvanic isolation compared to traditional Low-Frequency Transformers (LFTs), making them ideal for grid-supporting Electric Vehicle (EV) charging applications. However, the demand for ultrafast battery protection in these systems has driven the adoption of solid-state circuit breakers (SSCBs). Despite their advantages, SSCB-based protection systems require further advancements to ensure reliability and efficiency. This research focuses on designing and analyzing an SSCBbased battery protection system for SST-enabled EV charging grids, addressing overvoltage and overcurrent fault scenarios. The proposed system integrates an SSCB with a SiC MOSFETenabled Dual Active Bridge (DAB) and incorporates a decisionmaking algorithm with false-tripping ride-through capability, accounting for key factors such as hysteresis currents. The performance of the DAB model with the SSCB is initially evaluated through MATLAB/Simulink simulations under overvoltage and overcurrent conditions at the battery-emulated load end. The simulated results are validated with hardware implementation using a SiC MOSFET-based SSCB. The experimental results achieved an ultrafast overvoltage detection in less than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$490 \mu ~\mathrm{s}$</tex> results while the overcurrent protection system achieved ultrafast performance in less than <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$200 \mu$</tex> s which validated the ultrafast response of the proposed system. The findings demonstrate the system's robustness and effectiveness.