A High-Performance Cost-Effective Resonant Converter with a Wide Input Range in Solar Power Applications

In this paper, a novel hybrid-resonant PWM switching scheme is presented for an isolated high-performance and cost-effective LLC multi-resonant dc-dc converter with an output voltage-doubler in solar power applications. The new hybrid-resonant PWM switching scheme enables a resonant converter topology to achieve very high energy efficiency over a wide range of input line and load. The proposed control scheme not only maximized the efficiency, but also simplifies the implementation of MPPT in resonant converters. Finally, using SiC wide-band gap semiconductor technology will make it possible to operate these devices and the electronic board in an elevated temperate, thus achieving higher reliability and required life time. Experimental results are presented for a prototype unit converting input voltage range of 17 V to 48 V dc from a solar panel to an output voltage of 400 V dc at 250 W. The prototype achieves a peak efficiency of 98.5%.