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A High Step-Up Converter Using Transformerless Cockcroft-Walton Voltage Multiplier for a PV System

Nileena P. Subhash, Ajmal K.A, K. Punnagai Selvi

In this paper, a high step-up DC-DC converter with Cockcroft- Walton voltage multiplier module is proposed for a photovoltaic system. Through a voltage multiplier module, an asymmetrical interleaved high step-up converter obtains high step-up gain without operating at an extreme duty ratio. The voltage multiplier module is composed of a ladder network of capacitors and diodes to generate high voltages. In addition, the proposed converter functions as an active clamp circuit, which alleviates large voltage spikes across the power switches. Thus, the low-voltage-rated MOSFETs can be adopted for reductions of conduction losses and cost. Efficiency improves since the system uses a transformerless circuit and also the energy stored in leakage inductances is recycled to the output terminal. The modelling, control and simulation of the high step-up converter have been done using the software package MATLAB/simulink.