The Design Of The Multiple SVG Isolated By The Single-winding Transformer

Now,with the cocio-economic development,Grid introduces a number of non-linear loads.In the while,it’s brings so much power quality problems as voltage fluctuation,low power factor and flicker,three phase voltage unbalance, much harmonic. So,in china and abroad have been promulgated a series of voltage fluctuations and harmonic standards in order to ensure the power quanlity of supply system. In a number of reactive power compensation device to solve these power quanlity problems,SVG which based on IGBT with it’s fast response and good voltage-current characteristics of a number of superiority by the completion of the research focus of the governance field of power quanlity.The author undertakes the research and development work on reactive power compensation in Zhuzhou National Engineering Research Center of Converters Co.Ltd. This paper describes of research and development achievements-multiplex SVG for industrial loads in recent years.This paper studied the one topology of the SVG-multiplex SVG.Firstly,it introduced the basic principles of SVG,designed a compensation capacity±3000kVar multiple of SVG program,and calculated SVG system fixed capacitor(FC) capacity,number of branches,each branch capacity,connecting reactor,DC capacitor,the IPM module and other parameters;Then it introduced the reactive current and harmonic wave calculation based on instantaneous reactive power theory on the control strategy,and put forward the direct voltage control strategy based on the instantaneous power balance,and used the multiple carrier phase shift sine PWM(CPS-SPWM) and injection of the third harmonic SPWM modulation method;At last,it introduced the control hardware and software platform,and the hardware platform used dual DSP&dual FPGA as the master chip to ensure of the calculation speed and accuracy of the software and ensure of the platform scalability.the software used C language modular design,and improved the program’s readability and portability.The control system is the most important part in the SVGs which are made by different providers. The effectiveness of this system has been verified through the laboratory tests and the model projects. The test results showed that the system of the compensation device (SVG) is a rational design, a high Var control accuracy,and it’s response time is less than10ms.The device is running steadily from last year.so it is also satisfied the project actual require.