High Step-Up Interleaved DC–DC Converter with Voltage-Lift Capacitor and Voltage Multiplier Cell

In this article, a new high step-up interleaved DC–DC converter is presented for renewable energy systems. The converter circuit is based on the interleaved two-phase boost converter and integrates a voltage-lift capacitor and a voltage multiplier cell. A high voltage gain of the converter can be achieved with a reasonable duty ratio and the voltage stresses of semiconductor devices are reduced. Because of low voltage stress, the switches with low on-resistance and the diodes with low forward voltage drops can be adopted to minimize the conduction losses. Additionally, the switching losses are reduced because the switches are turned on under zero-current switching (ZCS) conditions. Due to the existence of leakage inductances of the coupled inductors, the diode reverse-recovery problem is alleviated. Moreover, the leakage energy is recycled and the voltage spikes during switch turn-off are avoided. The parallel input architecture and interleaved operation reduce the input current ripple. The operating principles, steady-state characteristics, and design considerations of the presented converter are proposed in detail. Furthermore, a closed-loop control is designed to maintain a well-regulated output voltage despite variations in input voltage and output load. A prototype converter with a rated 1000 W output power is realized for demonstration. Finally, experimental results show the converter effectiveness and verify the theoretical analysis.