Evaluation of the Parameters of a Soft Switching DC/DC Converter with a Modified Push-Pull Current Source Inverter Stage for Photovoltaic Systems

The article provides an assessment of the parameters of the power part of a DC/DC converter for transferring solar panel energy to a constant voltage network with the possibility of supporting the MPPT option. The primary stage has the push-pull topology of a current source inverter with an additional switch. The secondary stage is a half-bridge voltage source inverter. A special switching algorithm of separated commutation is described. It provides snubber turning-on of the current source inverter's switches and their natural turning-off in the mode of zero currents. The role of the non-dissipative turn-on snubber is performed by the leakage inductance of the matching transformer. For voltage source inverter MOSFETs the turning-on is natural in the mode of zero voltage. The role of the non-dissipative turn-on snubber may perform the own MOSFET's output capacance. Switches types were selected and static losses were estimated. Simulation confirmed the theoretical conclusions and the presence of soft switching modes of convertor's switches.