Closed-loop SHE-PWM technique for power converters through Model Predictive Control

In this work, a Model Predictive Control (MPC) strategy that combines Finite-Control-Set MPC (FCS-MPC) with Selective Harmonic Elimination (SHE) modulation pattern in its formulation is proposed to govern power converters. The key idea here is to define a desired steady-state in terms of the converter current and voltage. To do this, based on the converter current (system state) reference, an associated predefined SHE pattern is used as control input reference. Both system state and control references are included in the cost function. Therefore, during transients, the resulting predictive controller prefers to track the converter current while preserving the SHE pattern during steady-state. Thus, a fast dynamic response can be achieved throughout transients while a predefined voltage and current spectrum with low commutation frequency is obtained in steady-state by adjusting only the weighting factor of the cost function. Simulation results of the proposed SHE-MPC strategy when governing a Cascaded H-Bridge (CHB) converter are presented to highlight the benefits of the proposed predictive controller.