Adaptive Command Current Observation Algorithm of UPQC on Experimental Microgrid

The experimental microgrid is developed to test the feasibility of different source-network-load matching microgrid structures. The different combinations of distributed energy and loads put forward higher requirements for the accuracy and adaptive ability of power quality management. In this paper, the unified power quality regulator (UPQC) was used to control the power quality and a control strategy with adaptive ability to disturbance of the microgrid models was proposed. On the one hand, the adaptive observer was designed to detect the compensation current signal, which reduced the influence of voltage harmonic components on the compensation current detection accuracy while reducing the amount of observation calculation. On the other hand, aimed at the slow response of traditional PID to DC voltage fluctuation of inverters and thus affecting the accuracy of current observation, the nonlinear variable domain fuzzy controller, which can modify the fuzzy expansion factor online, was adopted to improve the real-time performance of the control. The algorithm was simulated in MATLAB platform, and the results verified the effectiveness of the control strategy. (paper)