Variable Switching Frequency Direct Power Control based on Sliding Mode approach for grid connected voltage source converters

Abstract

This paper presents a new sliding mode Switching Table direct power control for three-phase grid-connected voltage source converters (VSC). The proposed Direct Power Control (DPC) strategy employs a nonlinear sliding mode (SM) approach to directly calculate the required converter's control voltage so as to eliminate the instantaneous errors of active and reactive powers. In this configuration, the extra current control loops are eliminated, which simplifies system design and improves the transient performance. This improved control strategy combines the DPC strategy, sliding mode approach (SM), and switching table (ST) selection vectors technique, so as to directly regulate the instantaneous active and reactive powers of grid-connected voltage source converters. Simulation results for the proposed Variable Switching Frequency Direct Power Control based on Sliding Mode control approach (VSF-SM-DPC). The proposed VSF-SM-DPC is capable of providing enhanced transient performance, and keeps the steady-state harmonic spectra. The robustness of the proposed VSF-ST-DPC to the effect of the line inductance values mismatch is also inspected during active and reactive power changes. The proposed VSF-SM-DPC is inspecting to tracking capability with high-control bandwidth.