Transformerless Single-phase Grid-tied Micro Wind Turbine System Featuring Low Component-count

Abstract

In the presented paper, a single-phase micro wind turbine (MWT) grid-tied system is proposed featuring less component-count. The conventional bulky power conversion system, featuring a rectifier, DC/DC converter, single-phase voltage source inverter (VSI) and a step-up transformer, is replaced by only a rectifier and a single-phase current source inverter (CSI) for its voltage boosting capabilities and inherited short-circuit capability. Hence, the entire system size, cost and losses are reduced. Moreover, the VSI DC-link electrolytic capacitor is eliminated improving system reliability and lifetime. However, in the proposed system, the single-stage CSI is solely responsible for tracking the MWT maximum power and injecting it into grid. To achieve the latter, efficient control scheme is proposed along with a simple sinusoidal pulse width modulation technique that results in minimal harmonic in the grid current. Simulation work verified the proposed system effectiveness along with the proposed control scheme and PWM technique, under abrupt changes in the wind speed.