Energy efficiency improvements in wind energy systems via sensorless soft-switching control

Abstract

This study implements a series resonant converter (SRC) and pulse density modulation (PDM) power control strategies to minimize switching losses and improve the efficiency of an off-grid, small-scale wind energy conversion system (WECS). Additionally, the maximum power point tracking (MPPT) method was employed to further reduce costs and increase system reliability. The perturb and observe (P&O) MPPT technique was utilized, enabling operation at the maximum power point (MPP) without the need for wind speed data or an aerodynamic model of the turbine. The speed and power data required for the P&O algorithm were derived from the three-phase generator variables using the double second-order generalized integrator frequency-locked loop (DSOGIFLL) algorithm. The performance of a 1.5 kW WECS was analyzed through simulations conducted in Powersim (PSIM), and the results are presented. The analysis revealed that the designed system achieved an average MPPT efficiency of 97%. Furthermore, the efficiency of the resonant converter was measured to be 90% for the lowest wind speed and 93% for other wind speeds. These findings demonstrate that the proposed system offers a significant improvement in overall energy conversion efficiency, ensuring reliable and cost-effective operation of small-scale WECS, with an average system efficiency of approximately 90-93% across varying wind conditions.