THD reduction with grid synchronized inverter’s power injection of renewable sources

A control method for small domestic power plants using renewable energy is described in this paper. This method is not only capable of optimizing the working point of the plant but also implements active power factor correction and lowers the extant harmonic distortion in the line. The novel element in the proposed complex controller structure is the upper harmonic controller that minimizes the amplitudes of the 3rd, 5th 7th, 9th, and the 11th upper harmonic component in the output voltage. The proposed controller has been investigated by simulation in Matlab environment, and as a result, substantial improvement of the output voltage and current waveform could be achieved. Robustness of the method against nonlinear loads has also been tested.