Abstract: In order to solve the problem that the voltage gain is limited by the limit of the voltage gain because of the parasitic parameters in traditional boost converter and a series of problems caused by the presence of the leakage inductance in the traditional boost converter with coupled inductance, a new high gain coupled inductor boost converter for photovoltaic power generation system is proposed. Based on the traditional coupled inductor boost converter, the converter is added to the lossless absorption circuit composed of diode, inductor and capacitor. As the coupled inductor has the transformer effect, the new circuit has higher voltage gain, compared with the traditional boost converter with coupled inductance; Since inductance has the effect of inhibiting the rise of current, it can reduce the current stress of the switch tube when the switch tube is on; The lossless snubber circuit could absorb leakage inductance energy to suppress the voltage spike at bothends of the switch. When the switch is turned completely, the energy in the capacitor and inductance can be delivered to the load,which realizes the lossless transmission to further enhance the voltage gain. In order to verify the validity of the new coupled inductor boost converter, the simulation model of the new coupled inductor boost converter and the traditional coupled inductor boost converter are built on the MATLAB/Simulink platform. By comparing the corresponding simulation waveforms of the two models, it can be seen that the new converter has higher voltage gain and relatively smaller voltage and current stress on the switch tube than the traditional one.

Key words: coupled inductor, photovoltaic power generation, lossless snubber circuit, stress of the voltage and current