Specialized predictive SVPWM current control of back-to-back converters for wind power generation systems

This paper presents the specialized predictive SVPWM current control of back-to-back converters for large-scale wind turbine generator systems. The predictive SVPWM current control strategy in the inner loop is adopted to minimize the system delay and improve the current response so that the grid-side current harmonics can be sharply reduced. Besides, load current feed-forward compensation was added to reduce the dc-voltage ripples when the load was unexpectedly changed, so that dc bus voltage can be kept at a demand level during the regenerative feedback condition of the motor. Active and reactive current are controlled respectively in d-q rotating coordinate system and unity power factor rectifier can be achieved. The proposed switching algorithm can control the converter with wide input voltage and load current variations. For validation, the converter showed better and fast performance in both steady state and transient state than conventional SVPWM control methods. Simulation demonstrates the effectiveness of the proposed current control algorithm.