Grid Power Quality with Variable Speed Wind Energy Conversion

Abstract

In the grid new renewable resources are added to extract more power. This adds more of problems to grid connection. They are voltage fluctuations and harmonic distortion. In this paper various interfacing topologies are analyzed to get wind turbine power within the norms specified in IEC 61400-21. In this paper, a simplified control strategy is used. The front-end voltage source inverter is operated in hysteresis current control mode. The reference signals are derived from one of the phase voltage. The main objective of the proposed control is the three phase supply currents both in its waveform, magnitude and phase to follow three phase reference signals. When this is achieved, ideally the supply current will then be always sinusoidal, with robust control over its magnitude and phase, irrespective of the harmonics and unbalance of the load demand or the supply voltage system. This confirms nearly unity power factor on supply side with active and reactive power support from the wind turbine side.