DSP-based Photovoltaic Inverter

As the fossil fuel dries up and the environmental problems caused by traditional powergeneration get worse around the world, renewable and pollution-free energies are becoming thefocus of attention both economically and politically. Renewable energies include photovoltaic (PV)system and wind power generation systems. Cost at present hinders the large scale application ofrenewable energies, and research work in large amounts is still needed to improve the costefficiency. Photovoltaic system, also known as solar inverter, has won large popularity in recentyears because of its convenience and broad application prospect. But it has its major drawback inthe high production costs and lower conversion efficiency of the silicon solar panels. With newtechnologies in PV panel production and the advancement in the inverter efficiency, the cost of PVprojects will move to a reasonable level. Two main tasks are involved in connecting the solarminiature inverters to the power grid. One is to make sure that the solar miniature inverters work atits maximum power point (MPP). And the other is to infuse the Sine current to the power grid.This paper analyzes the evolution of the solar system and the general development trend ofthe solar power generation system, has a subjective speculation on the future development trend ofsolar power system inverter. Then put forward a design scheme of photovoltaic grid-connectedinverter. The whole design includes the overall block diagram, operation mechanism. Thehardware and software module are described in detail. The inverter can be implanted in oneindependent PV panel to make up a module, which can be installed in series or in parallel withother modules, thus solve the single-point defaults in the traditional PV generating system. Therated design power of the inverter is220W, and a simple crisscross flyback converter is used toachieve the output of the Sine half wave rectifier voltage and current. After passing through thecontravariant bridge, the output of full wave Sine voltage and current is realized. And the currenthas the same frequency and phase with the voltage of the grid. Also, the module has the function ofprotecting the island. The inverter, aimed at one single independent PV panel, can be connected toany photovoltaic assembly whose rated capacity is220W, output voltage range is between25Vand45V and the maximum open-circuit voltage is55V.Finally, the writer design a simulation module of parallel algorithm using the tool---MATLAB, the grid algorithm is proved to be validity by simulation. A grid-connected photovoltaic micro-inverter is made and carried on the function test, the test results prove that thesystem can work normally.