GI based Control Scheme for Single Stage Grid Interfaced SECS for Power Quality Improvement

Abstract-This paper presents an improved generalized integrator (GI) based control with a frequency locked loop for multifunctional three phase single stage grid interfaced solar energy conversion system (SECS) for power quality (PQ) enhancement of the distribution network under abnormal grid conditions. The perturb and observe (P&O) based maximum power point tracking (MPPT) technique is utilized to obtain peak power from solar photovoltaic (PV) array under varying atmospheric conditions. This control scheme provides unity power factor (UPF) operation, load balancing, harmonics mitigation and reactive power compensation. The improved generalized integrator control algorithm has an advantage of better DC offset and harmonics rejection capabilities as compared to a conventional second order generalized integrator (SOGI) algorithm. To substantiate the control scheme, tests are performed on a paradigm in the research laboratory for manifold operating conditions. Test results show the satisfactory behaviour under steady state and dynamic operating scenario such as unbalanced load, solar irradiations variation, voltage sag and swell and distorted voltage grid. The THDs (Total Harmonic Distortions) of the grid voltages-currents are achieved within constraints of grid code compliance of an IEEE 519 and 1564 standards.