The grid connected Wind Energy Conversion Systems (WECSs) have two practical topologies, the traditional fixed speed and the new variable speed. Variable speed systems have several advantages over the traditional ones, such as reduction of mechanical stress and increase in captured energy; however, the systems need a Power Electronic (PE) converter, in which the machine is connected to the grid via the PE converter. To improve the power quality and decrease electrical losses in the variable speed WECS, choosing a full control PE converter or a simple PE converter including an active filter is essential. In this paper, a new modulation technique is proposed to be used in a Shunt Active Filter (SAF) to improve the output current harmonics of a WECS, including a Permanent Magnet Synchronous Generator (PMSG) and the AC-to-DC converter. The filter contains three parts: the identification, modulation, and an inverter. Most identification methods are sensitive to non-sinusoidal sources, but in the proposed filter an algorithm is used to make it non-sensitive to some extent. The simulation results confirm the superior performance of the proposed SAF over the previous SAFs applied in wind energy conversion systems.

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