Maximum power point tracking control and voltage regulation of a DC grid-tied wind energy conversion system based on a novel permanent magnet reluctance generator

This research paper aims to employ a new permanent magnet reluctance generator in a variable speed wind energy conversion system (WECS) of a grid-tied distributed generation application. The grid integration of WECS is achieved through cascaded dc-dc converters ensuring maximum power extraction from the wind energy while maintaining a constant output voltage at the grid side. The surplus power is stored in a capacitor bank that is located in between the cascaded converters. The implemented maximum power point tracking (MPPT) control is a hill climb searching (HCS) algorithm that does not require the knowledge of turbine or generator characteristics. However this paper proposes a simple modification in the conventional perturb and observe (P&O) type HCS control and that is to use a 2-valued perturbation step instead of the constant one. A larger perturbation step is used when the operating point is away from the optimal and therefore a faster convergence to the MPP is achieved. On the other hand a small perturbation step is adopted at the end of convergence in order to have the minimum possible oscillations about MPP. A Simplorer-Simulink interface is developed to simulate and verify the proposed control scheme. The results confirm the maximum power trackability and robust voltage regulation of the control system under varying wind conditions and load disturbances.