Direct power control of grid-connected converters using sliding mode controller

This paper proposes a Direct Active and Reactive Power Regulation of Grid-Connected converters using Sliding Mode Control approach applied to three phase PWM converters. The DPC-SMC controller regulates the DC-link voltage, active and reactive power-flows of the grid-connected converter. The proposed DPC-SMC strategy scheme calculates directly the required converter´s control voltage. So as to eliminate the instantaneous errors of active and reactive powers without involving any rotating coordinate transformations. Meanwhile, there are no extra current controls loops involved, which simplifies the system design and enhances the transient performance. Constant converter switching frequency is achieved by using space vector modulation, which eases the design of the ac harmonic filter. Simulation results of the improved direct power control (DPC-SMC) are compared to standard direct power control (DPC) strategies. The robustness of the proposed DPC to line inductance variations is also inspected during active and reactive power changes.