A New Approach for Reactive Power Control of Single Phase Transformerless Inverter to Modify Power Quality in Stand-alone Micro-Grids with Current Leakage Elimination

Nowadays, there has been an increasing interest in transformerless inverter for grid-connected photovoltaic (PV) systems due to low cost, high efficiency, and light weight. One of the factors in describing a grid’s behaviors is the capability of reactive power control by the inverter. According to the standard VDE-AR-N 4105, the grid-tied PV inverters of power rating below 3.68KVA should attain power factor (PF) from 0.95 up to 0.95 lagging. Thus this paper presents a new topology with the ability to eliminate common mode leakage, to control reactive power, and to correct power factor. The generation and extinction of this current is analyzed. It is worth saying that none of the open loop structures presented so far can control the reactive power individually without any controllers. Therefore, here a new approach based on proportional – resonant controller with fast response-- is described. Simulations, done with the active load and RL load, show the excellent performance of the proposed algorithm. Then, a proposed inverter with 98 % efficiency is compared with H5, H6 and HERIC inverters.