Research On The Technology Of Parallel Inverter Based On Grid-connected System

Nowadays, exploring and using of new energy resources becoming more and more important, solar energy is accept commonly because of cleanness and economical. The whole world focuses on the use of photovoltaic. The PV grid-connected system will be the most important way to use solar energy, so it will be developed rapidly, and the inverter is the most important power converter in the PV generator system, whose performance will influence the whole system. The parallel of inverters can expand capacity and realize redundancy in power supply system. So it is considered as one of the research in the field of inverter technology. And the parallel technology can be divided into two parts by whether there is a wire among modules. If there is a wire among modules, the technology is called wire-parallel, whereas it's called wireless-parallel, and the wireless-parallel is more redundant. Nowadays it's often control the phase and amplitude through the active-power and reactive-power of the load.Firstly, the text narrate the significance and good foreground of the solar power using and introduce the main content of the text, the topology and operating principle of main circuit are analyzed in detail.Secondly, the paralleled inverter system is modeling, and the influence of filter on the parallel operation for inverter is analyzed, and the working modes of paralleled inverter which will caused circumfluence are argued also.Finally, an inverter controller composed of voltage-loop and current-loop was introduced, and then we analyzed circulation characteristic of parallel inverter. And a new improved droop method, P-Q droop coefficient regulation method, was proposed. Simulation results confirm the proposed method.