Deadbeat Predictive Current Control with High Accuracy Under a Low Sampling Ratio for Permanent Magnet Synchronous Machines in Flywheel Energy Storage Systems

The predictive current control for the permanent magnet synchronous machine (PMSM) shows great potential in applications like flywheel energy storage, owing to its fast dynamic response and simple structure. However, under low carrier ratio conditions, conventional deadbeat predictive current control (DPCC) exhibits drawbacks such as significant current prediction error, inaccurate instruction voltage calculation, and severe torque and flux linkage coupling. This paper proposes an improved DPCC method suitable for both high and low carrier ratio operation of the PMSM. First, a modified stator voltage equation is established considering rotor flux orientation error. By treating the dq-coordinates as stationary and accounting for rotor rotation within the control period, a dynamic PMSM model is developed, effectively suppressing cross-axis coupling under low carrier ratios. Simultaneously, a multi-coordinate variable synchronization method is also introduced to eliminate prediction and voltage errors caused by cross-coordinate computation, enabling precise deadbeat control across all carrier ratios. The experimental results demonstrate that the proposed method enhances torque-flux decoupling, improves current prediction and tracking accuracy at low carrier ratios, and offers a reliable solution for dynamic control in flywheel energy storage systems.