Low power wind energy conversion system based on variable speed permanent magnet synchronous generators

Abstract

Abstract-This paper presents a Low Power Wind Energy Conversion System based on a permanent magnet synchronous generator and a High Power Factor rectifier. To achieve a high power factor at the generator side, it is proposed a power processing scheme based on a diode rectifier and a boost DC-DC converter working in discontinuous conduction mode. The proposed generator control structure is based on three cascaded control loops that regulate the generator current, the turbine speed and the amount of power that it is extracted from the wind, respectively, following the turbine aerodynamics and the actual wind speed. The analysis and design of both the current and the speed loop have been carried out taking into consideration the electrical and mechanical characteristics of the wind energy conversion system, as well as the turbine aerodynamics. The power loop is not a linear one, but a Maximum Power Point Tracking algorithm, based on the Perturb and Observe technique, from which it is obtained the reference signal for the speed loop. Finally, to avoid the need of mechanical sensors, a linear Kalman Filter has been chosen to estimate the generator speed. Simulation and experimental results on a 2 kW prototype are shown to validate the concept.