A new five-phase to three-phase back-to-back current source converter based wind energy conversion system

Abstract

Wind energy is one of the fastest growing renewable energy sources. The increased penetration of wind power into the utility grid brings challenges such as voltage and frequency fluctuations, generator torque ripples, and grid faults to power converter design in wind energy conversion systems (WECSs). Multiphase PM generators offers a promising solution to many challenges due to their inherited advantages over the three phase counterparts including reduced converter per leg rating and reduced torque ripples, which directly affect the lifetime of the drive train. In high power applications, direct drive PM generators are usually employed. Among different topologies of power converters, current source converter features a simple converter structure, low switching dv/dt, and reliable short circuit protection. In this paper, a new wind energy conversion system is proposed based on a direct drive five-phase PMSG connected to the grid using current source converters (CSCs). The generator side converter, operating in the rectification mode (CSR), is controlled to control the DC-link current, while the grid side converter, operating in the inversion mode (CSI), controls the active and reactive powers injected to the grid. The five-phase generator side converter is controlled using sinusoidal pulse width modulation (SPWM), while conventional space vector modulation is employed to control the three-phase grid side. A 5 MW system with typical system data is simulated via MATLAB/SIMULINK to validate the proposed topology.