LAUSR

An improved model-free predictive current control scheme based on double voltage vector for two-level voltage source inverters (2L-VSIs) is proposed in this article. First, two basic voltage vectors (VVs) are chosen in each control period, whose durations are calculated based on the cost function. Then, a novel current gradient updating method is developed by using the applied two VVs to calculate the current gradients of the remaining six VVs. As a result, the stagnation effect can be eliminated and current ripples and total harmonic distortion can be reduced effectively. In addition, due to the nature of vector diagram symmetry, the processing of current gradient updating is simplified and the calculation speed is increased. The effectiveness of the proposed scheme is verified by simulation and experimental results from the 2L-VSI system.