Control of Wind Turbine Driven Permanent Magnet Synchronous Generator

Abstract

Nowadays renewable energy sources are playing a major role in power sector where power generation from major conventional ways is impractical. Among these wind power system is a better choice for its own advantages like it requires less land to install wind turbines, the land near it can be used for agriculture and most important it can be used for wide range of power generation. For small scale power generation PMSG is most popular due to its better efficiency. Here the excitation for rotor (field) is provided using a permanent magnet rather than a coil which leads to many advantages but one demerit is that the field flux cannot be controlled. Absence of field coils leads to reduction in copper losses and it can be coupled directly to generator without any gear box as it can be operated with more number of poles. In this work one machine side converter is designed which is used to maximize power taken by the turbine taken from wind at different wind speed which will enhance the efficiency of turbine. This control will be done by adjusting the duty ratio of DC-DC converter which will make the turbine to rotate at its optimum speed according to the variation in wind speed. As the system is needed to be connected to utility grid and the grid voltage and frequency is constant so accordingly we need a grid side control system which will regulate the dc voltage output of converter and will make the grid side voltage constant. For grid connected operation of renewable energy systems the accurate determination of grid phase angle is needed which can be done by using a phase locked loop technique (PLL) and harmonics can be minimized using this control system. A grid voltage oriented vector control scheme is implemented here for the reactive power compensation, harmonic reduction and grid synchronization.