A voltage-power self-coordinated control system on the load-side of storage and distributed generation inverters in distribution grid

Abstract

The uncertainty of the load-side operating state and time-varying power demand in the AC distribution grid seriously affects the output mode configuration and sustainable storage and distributed generation inverters (SDGIs) security. To enhance the self-coordinated output capability and simplify the complexity of multi-mode control systems, this paper innovatively designs a voltage-power self-coordinated control system utilizing sliding mode control (SMC). Firstly, a power transmission model for typical SDGIs is established, and based on the analysis of output voltage characteristics under active and reactive power constraints, the virtual compensation voltage is proposed to construct a voltage-power self-coordinated control relationship. Next, the SMC strategy is practically applied to implement the functions of each module in the control system through skillful combination, and its stability is analyzed based on the characteristics of the SMC control law. Finally, multi-condition simulation and experimental verification are designed. The results indicate that compared to traditional robust control strategies, the proposed strategy achieves an average improvement of 2.19 % in the output power accuracy of the SDGI, reduces the average output voltage harmonic by 1.43 %, and exhibits an average response time of only 0.021 s for the self-coordinated transformation of the system output state during load-side power fluctuations, which is a reduction of 0.043 s on average. This effectively enhances the robustness of the SDGI and its output performance in response to power variation and voltage sag at the grid side.