A Novel PV Converter

With the aggravation of the fossil fuels that are the oil, coal and so on, people pay more attention to the development and utilization of the renewable energy source. Among the renewable energy sources, the solar or photovoltaic energy has become one of the most promising sources of energy due to the fact that photovoltaic energy is rich, noise-free and environmental friendly and so on. With its modular design advantage, the ac-module grid-connected system becomes the future trend of the grid-connected photovoltaic system development.In order to overcome the problem of ac-module's lifetime that is limited by the aluminum electrolytic capacitors in the input. In this paper, these aluminum electrolytic capacitors are obviated by using two-stage converter and using the high voltage dc-link polypropylene capacitor to decouple the power that between the photovoltaic module and the grid, so the ac-module has long life time.This paper first study the performance of solar cell by simulation,and find that the intensity of sunshine and the temperature are the important factors of PV module's output power. The maximum power point of the PV module is tracked by controlling the input voltage of push-pull converter. The control model of inverter is got from the system's the energy sampled-data model, the balance of system is kept by modifying the amplitude of output current. In order to get unit power factor, the output current is controlled to track the voltage of grid. At the final, a 150W ac-module are designed, the design and debugging of the hardware and the software are finished. The achievement of the system is validated with the simulation results and the experimental waveforms.