Synchronous Dual-Switch Ultrahigh Step-Up DC–DC Converter Based on Coupled Inductor and Voltage Multiplier for Photovoltaic Systems

In this article, an ultrahigh step-up quadratic boost converter is proposed for photovoltaic systems. By integrating with a coupled inductor and a voltage multiplier, the voltage gain can be improved significantly without high turns ratio and the voltage stress across the power switches are alleviated. Thus, low on-resistance of the power switches is available to enhance efficiency. Common ground structure of quadratic boost and synchronous operation of the two switches facilitate the control. Also, the continuous input current promotes the maximum power point tracking (MPPT). Detailed description of the operation principles and steady-state analysis of this converter in continuous conduction mode and discontinuous conduction mode are presented. A 250-W rated laboratory prototype is fabricated and verified, demonstrating a maximum efficiency of 96.5%. Moreover, the dynamic response is tested to prove the stability of the proposed converter. Finally, a simulation is built to evaluate the feasibility of MPPT function.