Modelling and Simulation of Grid Connected PV System for Harmonic Reduction by Using Digital Filter

Power converters have become integral part of integrating most of the renewable energy resources into the grid. Amalgamation of these converters with the grid has been quite pragmatic but it is very much obvious every good thing has its own downside and in similar manner power converters being reliable, efficient and nearly maintenance free, have many demerits as well. Some of them being, tendency to add harmonics into the grid, reducing source and load side power factor and deviation of supply frequency. This leads to considerable rise in THD. Lots of techniques, control schemes etc. have been suggested to reduce harmonics and curtail down THD. One of the ways is adding filters to cancel the unwanted harmonics and reduce the load side THD. Previously a number of filters have been used for this purpose. They have their own merits and week points. Here we have proposed the use of digital IIR filter between load and inverter to get rid of deplorable harmonics from the system. Digital filters do not drift with temperature or humidity, or need components of precision and also they have better flexibility and reliability and there are no fluctuations due to ageing and that's why digital filters have an edge over other filters and because of expeditious design of IIR filters, they are preferred in this paper. Simulation analysis was done and the results have been justified in MATLAB.