Improved direct power control for Vienna-type rectifiers based on sliding mode control

This study proposes an improved direct power control (DPC) strategy based on sliding mode control (SMC) with dual closed loop for the Vienna-type rectifier to improve transient response during both start-up and load step-change periods and to guarantee stability in steady state. The inner power closed-loop utilises SMC–DPC controller to directly regulate the required rectifier's control voltage without transforming to synchronous rotating coordinate reference frame or tracking phase angle of the grid voltage, which simplifies the control system. In addition, the outer loop employs a novel sliding mode controller to improve the dynamic performance of the dc output voltage and the instantaneous power. Finally, the dynamic and steady-state performances of the grid current, dc output voltage, active/reactive power are experimentally investigated and compared with the conventional proportional–integral-DPC scheme, both the simulation and the experimental results demonstrated the dynamic performance and stability of the proposed control scheme.