A Simple Self-Clamped High Step-Up DC-Dc Converter Employing Coupled Inductor

Abstract

This paper proposes a high-voltage-gain boost-based converter employing a coupled inductor. The proposed circuit presents high efficiency, absence of clamping circuits for limiting the voltage spikes over all semiconductor devices and reduced number of components. Besides employing a coupled inductor, the converter also has two stacked capacitors in its output. Thus, the total voltage gain is defined by the duty cycle, the turns ratio of the coupled inductor and the sum of these two capacitor voltages, resulting in the high gain of the system. It is demonstrated that the efficiency is high, because extreme duty cycle values are avoided. Its steady-state operating principle are presented. So, it can be observed that maximum voltage spikes on the all semiconductors (main switch and diodes) is equal to the output voltage Vo, turning the proposed converter suitable for applications where voltage levels on the load need to be not too high (400 V - 600 V). Finally, experimental results in by open loop control are presented for 30 V and 48 V input voltages, 400 V output voltage, 100 kHz switching frequency and 300 W output power.