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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%. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper presents a novel bidirectional DC-to-DC converter charge/discharge controller for solar energy illumination system. The bidirectional converter architecture integrates the synchronous rectification Single Ended Primary Inductor Converter (SEPIC) converter and an active clamp flyback converter. In addition to fully use the properties of the shared components and compensate for the shortcomings of conventional two-stage illumination systems, the proposed system has the advantages of soft-switching, simple structure, and high efficiency. During daytime, a SEPIC converter with synchronous rectification function was used to charge the lead acid battery through three-stage charging and maximum power point tracking. At night, the battery discharges, driving and dimming high-brightness LEDs using the active clamp flyback converter. Finally, a solar energy illumination system with both a 160 W charge/discharge controller and an 80 W LED driver was implemented to verify the feasibility and practicality of the proposed system. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]