Abstract:In order to address the problem that the system performance of traditional control strategy of three-level inverter-fed permanent magnet synchronous motor decreases due to parameter changes, a model-free predictive current control method based on extended state observer is proposed to enhance the robustness of the system. Firstly, the ultralocal model of the system is established to predict the future current state, which does not involve any motor parameters and solves the problem that parameter changes affect the system performance. Then, for the total disturbance of the system, dq-axes’ expanded state observers are designed to estimate the nonlinear part of the ultra-local model. Furthermore, the optimal voltage vector is selected by cost function, and the balance control of midpoint potential is realized by using the redundancy characteristic of small vector. Finally, comparative experiments are conducted on a DSP experimental test rig, in terms of the traditional three-level model predictive current control, model-free predictive current control and the proposed method. The experimental results verify that the proposed method has preferable dynamic and steady-state performance and improves the anti-disturbance ability of the three-level drive system effectively.