Research Of The Chain STATCOM Based On Cascaded Multilevel

Since twenty-first Century, with the rapid update of knowledge,emerging technology obtained the rapid development, in the field of power system,chain STATCOM as representative of a new generation of reactive compensationdevice, provides a good solution for power system to improve power quality, Themodular design of chain STATCOM, convenient for capacity expansion, easyequipment installation, and covers an area of small, energy saving and environmentalprotection, stable performance and many other advantages, at present, the electricpower research agencies in many countries have carried out extensive and in-depthstudy, and also have practical application in a wide range of transport network in thereal, so we can clearly see that, in the wattless power compensation of future powersystem, chain STATCOM will become mainstream in the application of wattlesspower compensation equipment. So in this paper, a detailed analysis and Research onchain STATCOM, and according to the actual needs of main circuit and controlcircuit of the chain STATCOM has also made to study.This paper first introduces the development of these years national chain ofSTATCOM devices and the practical engineering application. Then the mathematicalformula model of chain STATCOM are introduced, and the mathematical model areanalyzed in detail. The principle of the chain STATCOM also conducted in-depthanalysis, according to the instantaneous reactive theory of three-phase staticcoordinate transformation to the two-phase synchronous rotating coordinate formulaswere derived. The bipolar SPWM carrier phase shift and unipolar dual frequencySPWM carrier phase shift of two modulation techniques are analyzed and compared,and through the MATLAB Simulink to build the simulation model, and compares theadvantages and disadvantages of two kinds of modulation.In the aspect of the control algorithm, Instruction control current of the chainSTATCOM device through the flat wave reactor coupled together, mutual influence,is not conducive to control, based on the above reasons, this paper put forward adecoupling current feed-forward decoupling algorithm for mutual coupling, anddecoupling of current after application of PI regulator to control, the currentdecoupling. Control is more stable, the control of Capacitor DC voltage on the DCvoltage balance control, and then through the PI regulator, the DC voltage capacitance side value good stability in the vicinity of a given value, which can provide stable DCpower capacity.Finally, according to actual needs of the project, the R&D and manufacturing ofthe chain of STATCOM devices have also carried out a detailed introduction, maincircuit components selection methods include chain STATCOM device, voltage andcurrent detection circuit, Zero voltage detection circuit, protection circuit, the maincontrol circuit chip of the control arithmetic circuit selection, the control algorithm ofthe implementation process, and finally gives Waveform of voltage, current Of theresearch and development of device through the oscilloscope during the experiment.The chain STATCOM principle is verified.