Interleaved high step-up converter with coupled inductor and blocking capacitor

A novel converter is proposed in this paper to satisfy the high power and high step-up conversion requirements. A voltage gain extension cell based on the coupled inductors and the blocking capacitor is introduced in the conventional interleaved boost converter to extend the voltage conversion ratio and reduce the switch voltage stresses. Therefore, low on-resistance switches can be used to reduce the conduction losses. The input current ripple is cancelled due to the interleaved control strategy. Moreover, the active clamp circuits are adopted to clamp the switch turn-off voltage spikes, recycle the leakage inductance energy, and realize Zero-Voltage-Switching (ZVS) turn-on performance for all the switches. Furthermore, the diode reverse-recovery problem is partly solved due to the leakage inductance. Finally, a 48V-input 380V-output 1kW prototype is built to demonstrate the theoretical analysis, and the maximum efficiency of 96% and 95.3% at full load are achieved.