This invention discloses a dynamic phase sequence spherical decoding multi-step predictive control method for common-mode
voltage suppression. It proposes incorporating a hard constraint mechanism for common-mode
voltage during the search process, effectively suppressing common-mode
voltage by
pruning high common-mode voltage
branch nodes, thus overcoming the problem of excessively high common-mode voltage in traditional spherical decoding predictive control. The method's computational reduction effect becomes more significant with increasing prediction step size. A dynamic phase
sequence search strategy is proposed, periodically rotating the search phase sequence to achieve a uniform distribution of
inverter switching frequency and reduce the risk of local overheating of the converter. This invention also proposes setting a hard constraint on the upper bound of the number of search nodes for spherical decoding predictive control, which can limit the
algorithm's search time as needed and avoid a surge in the number of search nodes under operating condition disturbances.
Simulation results based on a three-phase five-level active neutral-point clamped
inverter verify that this method can achieve uniform
switching frequency distribution, common-mode voltage suppression,
capacitor voltage balance, and significantly reduce computational load.