A single‐switch cascaded high step‐up voltage converter with 95% maximum efficiency for renewable energy systems

Summary This paper proposes a novel nonisolated single‐switch cascaded high step‐up converter. The converter consists of coupled inductors, a clamp circuit, and cascaded capacitors to achieve high step‐up voltage output. Only one switch is used in the proposed converter; the switch can reduce cost efficiently and simplify the control of the proposed converter. The converter also possesses an energy‐recycle mechanism for recycling the spike energy of a leakage inductor. In addition, a clamp circuit is used to reduce voltage‐stress across the switch, and a cascaded design is used to reduce voltage‐stress across diodes and output capacitor. Thus, the proposed converter can select a low‐voltage stress switch for reducing circuit loss and improving the efficiency of the converter. Finally, in this study, a 400‐W nonisolated cascaded high step‐up converter was implemented, of which the input and output voltages are 48 and 400 V, respectively. A microcontroller dsPIC30F4011 was used to control the converter and verify system effects and feasibility. The maximum efficiency of the proposed converter is 95% and the efficiency under a full load is 93%.