A General Constant-Switching-Frequency Model-Predictive Control of Multilevel Converters With Quasi-PS-PWM/LS-PWM Output

Abstract

Classical model-predictive control (MPC) of multilevel converters experiences poor steady-state performance owing to the noninterleaved and variable-frequency switching manner. To improve the steady-state performance of MPC, this article presents a general constant-switching-frequency MPC scheme for multilevel converters that can generate quasi-phase-shifted pulsewidth modulation (PWM)/quasi-level-shifted PWM output waveforms and the dc voltage utilization that compares well to that of the space vector modulation. In the proposed MPC scheme, parts of switching pairs of the multilevel converter are determined using the finite-control-set MPC using a hexagon selection approach, while the rest of the switching pairs of the multilevel converter are determined using the multiple-vector MPC for the constant-switching-frequency operation. The deadbeat approach is employed to reduce the computation burden of finite-control-set MPC. The basic concept of the proposed MPC is evaluated in both simulation and experimental tests on a five-level active-neutral-point-clamped converter.