Compensation Control Algorithm for Direct Drive Permanent Magnet Wind Generator under Unbalance of Three-Phase Source Voltage

This paper presents a new converter control algorithm for the direct drive permanent magnet wind generator under the unbalanced threephase source voltage. Based on the vector transform algorithm of the unbalanced threephase instantaneous voltage, the negative sequence current is decomposed and is added to the output current that is calculated based on PLL. The control strategy can guarantee that the output currents of the direct drive permanent magnet wind generator are sinusoidal and threephase balanced. The proposed algorithm overcomes the problem that the outputs of the direct drive permanent magnet wind generator are distorted when the source voltages are unbalanced. The proposed control strategy is simple and available, with less computational efforts. Moreover, it can be realized on separated components in hardware expediently with high reliability.