Inverter control strategy for direct-drive permanent magnet wind generator under unbalance of three-phase source voltage

Inverter control strategy for direct-drive permanent magnet wind generator under unbalance of three-phase source voltage is proposed in this paper. Based on vector transform algorithm of unbalanced three-phase instantaneous voltage, negative sequence current is decomposed. The negative sequence component is added to the output current which is calculated based on PLL. The control strategy can guarantee the output current of the direct-drive permanent magnet wind generator is sinusoidal and three-phase balanced. The solution is proposed to the problem that the output of the direct-drive permanent magnet wind generator is distorted when the source voltage is unbalanced. This control strategy is simple and available, with less computational efforts. The strategy can be realized on separated components in hardware expediently with high reliability.