Unified power quality conditioner simulation with photovoltaic grid-connected power generation and supercapacitor energy storage

With the widespread use of distributed generation, a large number of power electronic switches and nonlinear loads greatly deteriorate the power quality of the micro-grid(MG). In order to effectively address harmonics problems in the micro-grid, a novel control topology of the unified power quality conditioner based on photovoltaic grid-connected generation and super-capacitor energy storage (SCPV-UPQC) is proposed in this paper. The control system is able to calculate the appropriate compensation amount by extracting the fundamental and harmonic components in the current and voltage signals of the PCC point. And a fuzzy logic PI control method is proposed to adaptively adjust the parameters of the traditional PI controller to mitigate the harmonic distortion and other power quality problems of the MG. The proposed SCPV-UPQC structure based on the fuzzy PI control strategy is simulated in MATLAB/Simulink under a typical MG model, and the results illustrate that this method can significantly suppress the harmonics in the MG, verifying the validity and feasibility of the proposed UPQC structure and control strategy. The method can provide helpful assistance for harmonic control of the future AC or DC MG and even multiple parallel MGs.