Protection of Bidirectional Step-Up/Down Partial Power Converter against Short Circuit and Open Circuit Faults and Mode Transition Issues

This article discusses the potential challenges arising from open or short circuit faults occurring at the input and output sides of a partial power dc-dc converter. Voltage spikes appear in both fault scenarios across the low-voltage port switches, posing a risk of converter damage. Additionally, a concern arises from the inability of a micro controller to deliver accurate switching signals during converter mode changes, leading to an inrush current of high-voltage port capacitors between ports and subsequent converter damage. The paper elaborates on strategies for fault diagnosis, utilizing current sensor fault detection signals and observing control variable behavior. It introduces fault clearance methods involving the solid-state circuit breaker interruption and activation of the low-voltage port switches. A solution addressing the mode change issue is also proposed. Simulation results in PSIM software demonstrate the effectiveness of these strategies.