Research And Application On Control Method Of 660V STATCOM In The Mine Underground

With the application and rapid development of power electronic devices, a large number of harmonic sources are produced and cause seriously effect in coal mine. As a part of reactive compensation and harmonic suppression, STATCOM has a good effect.STATCOM based on LCL filter was designed in this thesis. Firstly, an optimized method of LCL filter for minimal damping power loss was proposed, which had the advantages of small damping, good filtering and small occupation area. Simultaneously, the selection rules of switching device and its drive were analysed. In addition, an optimization method of capacitance value based on the second harmonic content of capacitor voltage was proposed, which can realize the capacitor voltage fluctuate in the allowed range.Secondly, the principle of the indirect current control based on the feedback decoupling and the direct current control based on fixed switching frequency were introduced. Based on this, a double hysteresis tracking control method based on voltage space vector was proposed. By MATLAB/Simulink simulation, this method had the advantages of low switching loss, less heat dissipation, fast dynamic response and high compensation accuracy. Voltage control method of power module used the injection of negative sequence current. The thesis focused on introducing the parameter selecting method of PI controller in the voltage control loop. By MATLAB/Simulink simulation, the results showed the design can reduce the capacitor voltage fluctuation, and the output current tightly followed the instruction current.According to the working environment in the pit, the explosion-proof measures and cooling measures of STATCOM were studied, and a set of whole system was design. By fixing the STATCOM in the 660 V side, the power parameters of winch transformer outlet side were measured by using power quality analyzer HIOKI3196. The result showed that the voltage and current distortion rate was reduced, and the power factor reached about 1 after STATCOM compensation, which can meet the requirements of reactive power compensation and harmonic suppression.