Novel maximum-power-extraction algorithm for PMSG wind generation system

The paper focuses on the development of a novel maximum-power-extraction algorithm (MPEA) including a maximum-power error-driven (MPED) mechanism and a maximum-power differential-speed (MPDS) control, for a wind generation system with a permanent-magnet synchronous generator (PMSG). In the proposed MPEA scheme, the MPED mechanism, operating like a traditional hill-climbing method, drives the output power gradually increasing to its maximum value by regulating the direction of current command according to the power variation trend. The MPDS control produces an additional step of current command based on the instantaneous difference of generator speeds, so that it can prevent the wind turbine from stalling at the suddenly dropping wind speed and achieve the object of maximum power extraction instantly as a stiff wind flowing through the wind turbine. In addition, the output is connected to a utility grid for providing energy flexibility via a unipolar full-bridge inverter controlled by a digital signal processor. The grid-connected experimentations of the proposed MPEA scheme, without any mechanical sensors for a wind-power emulation system via a PMSG driven by an induction motor, are given to examine its feasibility in practical applications.