Multilevel inverters for permanent magnet synchronous generator using wind power generation system

摘要

Wind energy is an important area of application for variable-speed generators which operates on the constant grid frequency. Power electronics perform the control of Wind Energy Conversion System (WECS) which allows the completion of grid requirements. This paper gives a detailed account about the operation of Multilevel Inverters for Permanent Magnet Synchronous Generator (PMSG) using Wind Power Generation System connected to grid by means of power electronic interface. This system incorporates low to medium wind speed operation. It consists of two back-to-back Pulse Width Modulation (PWM) converters with a common dc-link. Maximum power point tracking (MPPT) is achieved by using the generator-side converter control. The grid-side converter is controlled with force to feed generated power as well as to supply the harmonics and reactive power demanded by the local load at Point of Common Coupling (PCC). It enables the grid to supply only sinusoidal current at unity power factor. The voltage management and interactions of active and reactive powers are done by Proportional Integral Controller. The method of Hysteresis current control is adopted for the controllability of quick current. The result is analyzed by comparing the PWM inverter output with multilevel inverter. A model of directly driven PMSG-based variable speed WECS is developed and is simulated. In order to validate the control strategy adopted, the results are obtained under MATLAB/Simulink.