Bidirectional Interleaved PWM Converter with High Voltage-Conversion Ratio and Automatic Current Balancing Capability for Single-Cell Battery Power System in Small Scientific Satellites

Single-cell battery power systems are a promising bus architecture for small scientific satellites. However, to bridge the huge voltage gap between a single-cell battery and power bus, bidirectional converters with a high voltage conversion ratio and a large current capability for the low-voltage side are necessary. This article proposes a bidirectional interleaved pulse width modulation (PWM) converter with a high voltage conversion ratio and an automatic current balancing capability. By adding capacitors to conventional interleaved PWM converters, not only are inductor currents automatically balanced without feedback control or current sensors, but also voltage conversion ratios at a given duty cycle can be enhanced. Furthermore, the added capacitors can reduce voltage stresses of switches and charged-discharged energies of inductors, realizing more efficient power conversion and reduced circuit volume in comparison with conventional converters. A 100-W prototype was built for experimental verification, and results demonstrated the fundamental characteristics and efficacy of the proposed converter.