Research On System Design And Experiment Of The Low Voltage STATCOM

With the use of power electronic devices and various nonlinear equipments,as well as the constant improvement of the users' higher requirements to power quality, the reactive power compensation issue in the quality of power has become increasingly important.Use static synchronous compensator(STATCOM-Static synchronous compensator) to achieve dynamic reactive power compensation is one of active research areas in the power electronic disciplines.However,the current study on static synchronous compensator is mainly concentrated in the transmission system and the current control methods based on the indirect control.With the impact of switching frequency and switching capacity of the switching devices,the STATCOM devices using indirect current control methods exists harmonic output,and the response speed and the control precision have yet to be enhanced.The STATCOM technology applying in the low-voltage distribution system or industrial load compensation in the country is relatively low at present,and the technology was not mature.This paper introduces a STATCOM device based on the direct current control using in low-voltage distribution system or industrial load according to their characteristics.This paper established the mathematical model of STATCOM using direct current control,in this paper we use the operational method of i_p,i_q which based on the instantaneous power theory to test the operations of reactive current and the harmonic current;Compared to the direct current control methods,the direct current control are more advantage in the tracking speed and the precision of control,so we design the control section according to the direct current control,and verify by using the MATLAB simulation software.The DSP CMOS chip TMS320F2812 of TI Company is used as CPU and the hardware and software of a DSP+CPLD digital control electric system which is proposed for STATCOM is designed.The digital control electric system project illuminates the peripheral interface current of DSP particularly and designs the pretreatment circuit of analog signals,synchronal detection circuit and the interface circuit of DSP and CPLD.At last,experiment using the dynamic harmonic var generator(DHVG) as a simulated load.The results proved the feasibility of the design,but also the good performance of dynamic compensation of the STATCOM.Comparing with the results of the simulation and experiment to proved the feasibility of the design;through the experiment of the STATCOM to prove the good performance of reactive power compensation and dynamic response speed.