Abstract: Aiming at the problems of large current ripple, stagnant current gradient update and sampling noise interference in the model-free predictive current control (MFPCC) method of grid-connected inverters based on look-up table (LUT), a three-vector model-free predictive current control method with sampling noise compensation is proposed. Firstly, the output current of each control period is predicted by the current gradient corresponding to the three-voltage vectors, and the action time of each vector is solved by the cost function to reduce the current ripple. Secondly, according to the overlapping relationship between the coordinate components of the three vector and the basic vector, the two-step updating method is used to eliminate the stagnation phenomenon. Finally, according to the influence of sampling noise on current gradient updating, a second-order generalized integrator (SOGI) is used to estimate and compensate the gradient error, so as to improve the accuracy of current gradient. Simulation and experiment verify the feasibility and effectiveness of the proposed method.

Key words: grid-connected inverter, model-free predictive current control, three vector, gradient update stagnation, sampling noise compensation