A Fixed Switching Frequency Model Predictive Control Strategy With Reactive Power Handling Capability and Improved Current Tracking for Vienna Rectifiers

Vienna rectifiers are widely used for high power density AC–DC conversion in applications such as electric vehicle chargers, power supplies, and industrial front-end rectifiers. The control of Vienna rectifier is challenging owing to its multi-objective control requirements, for which finite-set model predictive control (FS-MPC) is attractive. However, conventional FS-MPC suffers from variable switching frequency, while recently reported fixed switching frequency (FSF) FS-MPC methods face issues such as input current distortion, neutral-point (NP) voltage balancing challenges, and poor reactive power control capability. This paper proposes a new FSF FS-MPC algorithm that addresses these issues by introducing a modified five-segment switching sequence, which redistributes dwell time to restore reactive power handling capability and also achieves NP voltage control. Additionally, the method incorporates compensation for converter non-idealities to enhance current reference tracking. Simulation studies and experimental results from a Vienna rectifier hardware prototype validate the effectiveness of the proposed FSF FS-MPC algorithm. Comparative analysis shows that the proposed FSF FS-MPC algorithm achieves significantly reduced input current total harmonic distortion (THD), improved current tracking, NP voltage balancing, and enabled reactive power support, all while maintaining a fixed switching frequency.