Full soft-switching high step-up DC-DC converter based on active resonant cell

In this paper, a new full soft switching high step-up DC-DC boost converter is proposed. To achieve high voltage gain, a N-level voltage multiplier cell (VMC), and to achieve soft switching, a simple auxiliary resonant cell is implemented on a conventional pulse width modulation boost converter. All semiconductor devices are switched under soft switching conditions, which decrease the switching losses significantly. These soft switching conditions consist of zero voltage and zero current switching (ZVZCS) condition for both main and auxiliary switches, ZVZCS for auxiliary cell diode and zero current switching for all output VMC diodes. To control the output voltage in this converter, two degrees of freedom, consisting of the main switch duty cycle and output VMC level (N), are available. These degrees of freedom lead the converter to operate in a wide output voltage range and have maximum power point tracking implementation or output voltage regulation capabilities. In this paper, operational modes analysis, design procedure, application discussion, soft switching and power efficiency evaluations and simulation results are presented. Finally, experimental results with input voltage of 32V, output power of 80W and switching frequency of 20kHz are given to prove the accuracy of theoretical analysis.