Дослідження впливу LC-фільтра на роботу UPQC-VAmin при зміні напруги джерела живлення

Abstract

The article is devoted to the assessment of the influence of the parameters of the output LC low-pass filter of a series power active filter on the flow of active power and the indicators of harmonic distortion of current and voltage in the system of a unified power quality regulator with a minimum installed power (UPQC-VAmin). The study of the LC filter was performed on the basis of modeling in the Matlab/Simulink environment for a three-phase four-wire system operating with a nonlinear load. The object of the analysis is to establish the relationship between the output inductance, the alternating voltage of the power source in the range (340 to 440 V) and key indicators: active power UPQC-VAmin, the harmonic distortion coefficients of the network current, voltages on the load and the network. Two common LC filter configurations were investigated: with a fixed capacitance of 100 μF with a variable inductance in a predetermined range 0.1 to 3.1 mH and with stabilization of the resonant frequency within the minimum inductance and capacitance of the LC filter. The study was conducted for the calculated power supply circuit nodes ed within the voltage range varying in the range –15 % to +10 % with a step of 10 V and an L-filter inductance of 0.1–3.1 mH with a step of 0.2 mH, which allowed constructing precision response surfaces and establishing the dynamics of the course of electromagnetic processes. The characteristic dependences of the active power flow in UPQC-VAmin on the input voltage were analyzed. It is proved that uncontrolled growth of inductance over 2 mH at constant capacitance leads to the emergence of resonance phenomena, which increase the level of harmonic distortion of the network current to 5.5 %. Zones of minimal voltage distortions on the load are determined, which confirms the reliability of the ed control system. According to the principle of Pareto optimality, the obtained results demonstrate the minimization of the coefficients of harmonic distortion of current and voltage.