Design and analysis of a high step-up single-switch coupled inductor DC-DC converter with low-voltage stress on components for PV power application

摘要

This paper presents a single-switch, high step-up, non-isolated DC-DC converter for photovoltaic (PV) power application. The proposed converter is composed of a coupled inductor, a passive clamp circuit, a voltage multiplier cell, and a voltage lift circuit. The passive clamp circuit recovers the leakage inductance energy of the coupled inductor and limits the voltage spike on the switch. Configuration of the passive clamp and voltage multiplier circuits increases the converter voltage gain. High-voltage gain without a large duty cycle, low turn ratio of the coupled inductor, low-voltage stress on the switch and diodes, leakage inductance energy recovery, and high efficiency are the main merits of the suggested DC-DC converter. Steady-state operation of the converter in continuous conduction mode (CCM), discontinuous conduction mode (DCM), and boundary condition mode (BCM) is discussed and analyzed in detail. Then, design procedure of the proposed converter is given. The presented DC-DC converter is compared with similar topologies to verify its advantages. Moreover, theoretical efficiency of the presented converter is calculated in details. Finally, simulation and experimental measurement results of 388 V-220 W prototype of the proposed DC-DC converter at 50-kHz switching frequency are presented to verify its performance.