A novel model predictive sliding mode control for AC/DC converters with output voltage and load resistance variations

This paper presents a novel model predictive sliding mode control (MPSMC) strategy for a three-phase grid connected AC/DC converter. The grid current is predicted for controlling the active and reactive power flows for the next sampling time instead of predicting them directly. This MPSMC scheme employs a sliding mode control (SMC) algorithm to calculate the reference values of active and reactive powers in the cost function. The reaching, existing and tracking conditions are analyzed to ensure that the designed sliding surface and control law are effective to control the system. The simulation results by Matlab/Simulink show that the MPSMC strategy is able to meet the system requirements of active and reactive powers, as well as the DC output voltage. Compared with the results obtained from the conventional model predictive PI control (MPPIC) scheme, the proposed strategy can improve the dynamic performance dramatically in terms of the response speed under system disturbances, such as varying output voltage and load demand.