Current source converter topologies for PMSG wind turbine applications

Different current source converter topologies for permanent magnet synchronous generator (PMSG) wind turbine applications are presented and analyzed in the paper. In high-power and medium-voltage range, current source converter has its natural advantages, such as simple topology, compact size, high power capability, excellent short circuit protection, and flexible power flow control. However, it also presents some challenges for control scheme development. In the paper two different approaches are shown. One utilizes phase control thyristors and active filter for harmonics compensation, while other uses PWM controlled SGCTs. By controlling the inverter modulation index at the highest possible level, the proposed control scheme keeps the dc link current at a minimum value with various wind speeds and therefore greatly reduces the converter power loss at lower power levels. Simulation results are given for both control schemes.