Control of variable speed wind energy conversion system using a wind speed sensorless optimum speed MPPT control method

This paper presents a wind speed sensorless maximum power point tracking (MPPT) controller for variable speed wind energy conversion systems (WECS). The proposed controller generates at its output the optimum speed (OS) command for the speed control loop of the vector controlled machine side converter control system without requiring the knowledge of wind speed. The MPPT control of the WECS is achieved using optimum speed-power curve of the WECS taking into account the variation of the system efficiency while operating at various operating points due to the change in wind speed. The method is based on the fact that the optimum output power of a WECS at a certain wind speed depends upon the total mechanical power developed by the turbine and efficiency of the WECS at the corresponding OS of rotation of the turbine. The controller algorithm implementation requires the knowledge of turbine parameters and output power and air density as its inputs. The proposed concept is analyzed in a variable speed direct drive permanent magnet synchronous generator (PMSG) WECS. Experimental results show good tracking capability of the proposed controller.