Current control for third-harmonic injection two-stage matrix converter under unbalanced input voltages

A predictive control scheme for the third-harmonic injection two-stage matrix converter (3TSMC) under unbalanced input voltages is presented. The proposed scheme is designed to predict the future behavior of the third-harmonic injection current and load currents respectively for each valid switching state. The control scheme selects the state that minimizes the error between the predicted currents and references. For the 3TSMC, the input currents are synthetized by the injection current. In order to keep sinusoidal input currents under unbalanced input voltages, the reference of the third-harmonic injection current is obtained by symmetrical component extraction. Firstly, this paper introduces the proposed control method, including establishing the discrete-time model and selecting cost functions. Then, the extraction for the reference of injection current is presented. Finally, this paper shows the simulation results to demonstrate that the proposed control method can generate good tracking of input and output currents under unbalanced input voltages.