Phase-Shedding Control Scheme for Wide Voltage Range Operation of Extended-Duty-Ratio Boost Converter

Abstract

In this paper, a phase shedding control scheme for extended-duty-ratio (EDR) boost converter is proposed to achieve wide input and output voltage range operation of the converter. EDR converters can achieve very high gain, for example above 20 for a 4-phase converter, but have limitations on the lowest allowable gain. The proposed scheme allows operation at gain as low as unity while retaining the main benefits of EDR boost such as low voltage stress across switches. The phase shedding control can be optimized based on the application requirements. In this paper, the phase shedding control is optimized for low device voltage stress over wide input and output voltage range operation. The converter control implementation is discussed in detail. The control scheme is verified with a 4-phase EDR boost converter with input voltage varying between 20 V–40 V and output voltage ranging between 50 V–400 V. Experimental results of closed loop operation with adaptive PI controller are presented and the phase shedding scheme is verified by showing the transition from one configuration to another based on the converters varying gain.