Control of parallel multi-converters for permanent magnet wind power generation systems

This paper proposes a control strategy for megawatt-level direct-drive wind energy conversion systems based on permanent magnet synchronous generators (PMSG). In the paper, a peak current model of zero-sequence current is derived and analyzed. The parallel-operation controllers are designed to restrain reactive power circulation and beat-frequency zero-sequence currents caused by discontinuous space-vector modulation (SVM). The control scheme does not change the configurations of the system consisting of parallel multiple converters. It is easy to implement for modular designs. The test platform has been set up and the experimental results proved the effectiveness of the control strategy.