Finite Control Set Model Predictive Current Control with Constant Switching Frequency Regulation for PMSM Drives

Due to the absence of a modulator stage, finite control set model predictive control (FCS-MPC) exhibits a variable switching frequency, which is one of the main drawbacks when it is applied to power converters and motor drives. Conventional methods achieve the constant switching frequency by modifying the cost function. However, an additional weighting factor is required. In this paper, a novel FCS-MPC with the constant switching frequency is proposed. To avoid the use of a weighting factor, a current error control band (CECB) is used to balance the current control and switching frequency regulation. Furthermore, it is investigated that the switching frequency decreases as the width of the CECB increases. Based on this principle, a switching frequency controller is proposed to online adjust the width of the CECB according to the switching frequency error between the reference and feedback values. This method allows FCS-MPC to operate at a reduced switching frequency. More importantly, the switching frequency can be concentrated at a constant value without requiring the weighting factor. The proposed method is verified experimentally under various operating conditions. © 2025 Institute of Electrical Engineers of Japan and Wiley Periodicals LLC.