Design of photovoltaic high frequency link inverter based on push-pull forward converter

In this paper, a photovoltaic high frequency link inverter is proposed. The inverter is constituted of push-pull forward DC-DC converter and DC-AC inverter full bridge. The push-pull forward converter has some superiority in low voltage high current situation and achieves electrical isolation between the photovoltaic battery and the AC output. The push-pull forward converter is used to convert the photovoltaic battery output voltage into high frequency square wave, which, in turn, is rectified and filtered to a high-level direct voltage. Then this high-level direct voltage is converted into a low-frequency wave by single phase SPWM inverter. In inverter, a PID digital controller is applied to achieve high performance in both the command tracking and the load disturbance regulation. The control strategy is realized by using the TMS320LF2812 DSP. Theoretical analysis and experimental results indicate that the proposed topology and control scheme are promising for the applications of photovoltaic power supply.