Coordinated control strategy of UPQC by dynamic collaborative task-solving scheme based on multi-agent system

Abstract

The conventional unified power quality conditioner (UPQC) includes a series active power filter (SAPF) and a parallel active power filter (PAPF). The former is used for voltage compensation, whereas the latter is used for harmonic and reactive power compensation. Because the SAPF always maintains an idle state, the UPQC function is relatively independent, and its utilization rate is low. To improve the UPQC performance more efficiently, a coordinated control strategy for UPQCs is established using a dynamic collaborative task-solving scheme based on a multi-agent scheme is proposed. First, the dynamic collaborative task-solving scheme based on a multi-agent system is illustrated. Next, the theoretical analysis of reactive power flow in a UPQC is discussed. Considering that no power quality problems such as voltage sag exist on the series side of the UPQC, the SAPF is used for reactive power compensation, and the PAFP is used for harmonic compensation based on the coordinated control strategy. To verify the validity and feasibility of the proposed control strategy, a simulation model is constructed in Simulink. The simulation results demonstrate the feasibility and validity of the proposed coordinated control strategy. The experimental results prove that the SAPF and PAPF can compensate for the reactive power and harmonics, respectively. The proposed strategy can be employed to improve the power quality of the microgrid effectively. Furthermore, it improves the comprehensive compensation performance of UPQCs and provides a new method for engineering applications.