A Constant Switching Frequency Finite-Control-Set Predictive Current Control Scheme of a Five-Phase Inverter With Duty-Ratio Optimization

Abstract

As is well known, the additional low-order harmonic currents and the huge computation amount of the cost function value with all available control sets are the two special issues of finite-control-set model predictive current control (FCS-MPCC) for multiphase inverters. Thus, this paper proposes a FCS-MPCC scheme with duty-ratio optimization for five-phase inverters. First, a group of the reconstructed virtual voltage vectors (V3) with low-order harmonic elimination is defined and employed as the control sets in FCS-MPCC scheme. Thus, it leads to no requirement for harmonic items and weighting factors existing in the cost function. Then, a combination of zero vectors and the selected V3 during each control horizon is adopted to rearrange the pulse sequence, which can realize constant switching frequency. In addition, the durations of the selected V3 and zero vectors during each control horizon are also estimated to minimize the steady-state current ripples in different subspaces based on the cost function optimization. Finally, a comparison of the proposed V3-FCS-MPCC scheme and the other FCS-MPCCs are presented in simulation and experimental test. Simulation and experimental results verify that the proposed V3-FCS-MPCC scheme can remain the simplified structure, fast dynamic performance, constant switching frequency, and achieve minimum current ripples in different subspaces.