Analysis of nonisolated ZVZCS DC-DC converter for high-power and high step-UP applications using resonant PWM technique

As the demand for Nonisolated (Zero-Voltage Zero-Current switching) ZVZCS DC-DC converter with high voltage gain is increasing day-by-day. Many industrial applications requiring this device for the renewable and green energy sources of power, fuel cell systems, uninterrupted power (UPS) supply and hybrid electric vehicles. The proposed method consists of Nonisolated ZVZCS Resonant Pulse Width Modulation (RPWM) high step-up dc-dc converter with improved switching technique suitable for high power applications. The proposed converter gives zero-voltage switching turn ON of the switches as well as reduced turn off losses at switching with continuous conduction mode (CCM), consisting of resonance in the auxiliary circuit. As a result of proposed method, considering small duty cycle reverse recovery losses of diodes become negligible with reduced current rating of the switches and comparative analysis between RPWM and PWM method is carried out. Also the auxiliary capacitance of the circuit becomes negligible which gives reduced volume and cost of the converter compared with Pulse-Width Modulation (PWM) method. In order to verify the results 2 kW Nonisolated ZVZCS DC-DC converter is designed in MATLAB/SIMULINK and compared with theoretical results.