Control Method of Flying Capacitor Converter Operated in Discontinuous Current Mode for High Voltage Photovoltaic Cell

This paper proposes the operation method of DCM applied to inductor current control of a flying capacitor converter (FCC) for the low boost ratio. Due to the charging and discharging of the flying capacitor, the inductor current ripple in FCC is reduced compared to that of the typical boost converter with the same inductance. The operation analysis for high boost ratio have been applied by authors. However, the duty calculation for light load region of high boost ratio cannot be applied because the slope of the modes II and III are inverted when boost ratio is less than 2. Thus, the operation analysis for low boost ratio is proposed in this paper. The validity of the proposed method is confirmed with a 1-kW prototype. As the experimental results, an efficiency of 98.1% is achieved.