Fault-Tolerant Modular Switched-Capacitor DC-DC Converter (MSCC) for Fuel Cells

Abstract

This study presents a new modular switched-capacitor DC-DC converter (MSCC) which is primarily designed with fault-tolerant capability to promote low-voltage applications such as fuel cells and photovoltaics. The converter can increase a low voltage level to a high voltage level by increasing the number of modules and/or the duty ratio. The proposed topology is modular and has high scalability for a high voltage gain. Another key advantage of the converter is its fault tolerance feature with a minimum change to the duty ratio. The proposed topology is first modeled analytically and then simulated in PSIM software with new control algorithms. The circuit architecture, operating principle, voltage/current stress and fault-tolerant operations are verified by using analytical and simulation methods based on a 200-V voltage supply. Moreover, experiments are also carried out on a low-voltage DC-DC prototype converter for validating the voltage ratio, efficiency and reliability. Test results have proved the effectiveness of the proposed topology under normal and fault conditions (open circuit faults of switches and capacitors). In addition to fuel cells, the developed converter can also be applied to photovoltaics and other low-voltage DC power systems which demand high efficiency, voltage output and high reliability.