A Direct Model Predictive Control Strategy with Optimized Sampling Interval

In this paper we present a direct model predictive control (MPC) scheme with time-varying sampling intervals. These sampling intervals are computed based on modulation (half-)cycles, which are obtained offline and stored in a look-up table. By utilizing the optimized modulation (half-)cycles and combining control and modulation in one computational stage, the proposed direct MPC scheme achieves lower current total harmonic distortion (THD) than conventional linear controllers with a dedicated modulator, and fast transient responses that characterize direct control methods. The effectiveness of the proposed control scheme is verified on a variable speed drive system consisting of a two-level voltage source inverter and an induction machine.