Power quality improvement of grid-connected wind energy conversion system for optimum utilization of variable speed wind turbines

This paper presents an improved technique for the power quality of the electrical part of a wind generation system with a synchronous generator (SG). The main aim is to optimize the utilization of wind power injected into the grid. To realize this goal, an uncontrolled rectifier-digitally controlled inverter (URDCI) system is proposed. The advantage of the proposed system is its simplicity due to reduced number of controlled switches which leads to less control complexity. The inverter system provides economic utilization of the wind generator by insuring unity power factor operation under different possible conditions. It also provides full control of active and reactive power injected into the grid using a digitally controlled voltage source inverter (VSI). A voltage oriented control (VOC) scheme is presented in order to control the energy to be injected into the grid. In an attempt to minimize the harmonics in the inverter current and voltage and to avoid poor power quality of the wind energy conversion system (WECS), an LC filter is inserted between VOC VSI and the grid. Simulation results are carried out to validate the proposed solution. The proposed technique is implemented by a digital signal processor (DSP TMS320F240) to verify the good performance of the proposed control system and agree with the simulation results to a great extend. The results verify the validity of the proposed model and show its practical superiority in renewable energy applications.