Design Of Static Var Compensator's Digital Control System Based On DsPIC

In the current distribution network, because of including many swing capacity (such as AC electrical arc furnace, rolling mill and welding machine), lead to voltage fluctuations and flicker, voltage and current waveform distortion, lower power factor and an imbalance of three-phase power supply, so it can give rise to reduce of the electrical energy and raise of the dissipation. Therefore, it is necessary to take some measures to deal with these issues, for example, the SVC device is able to solve these problems. So it is very important to design a quick-response and steady SVC device.Under this background, this thesis was written on the basis of TCR SVC digital control system which was developed by Northeastern University and Anshan Huaxia Power Electronic Equipment Corporation. A TCR SVC digital control system for 15kV AC electrical arc furnace was designed in this thesis with the help of dsPIC digital signal controller. A prototype of digital control system was designed and laboratory debugging was completed with all the targets achieved satisfactorily.The main works of this thesis are shown as follows:(1) According to the working principle of SVC and working characteristics of TCR, proposing the overall design proposal of SVC's digital control system.(2) Using dsPIC30F6014A as core controller, according to the compensation principle of three-phase unbalanced load, designing hardware circuit of the TCR SVC's digital control system.(3) Designing the software flow chart of the digital control system, programming the software procedures of parts of modules. In the calculation of the thyristor gating delay angle, using the rational interpolation to construct a rational interpolation function, to express the relationship between the thyristor gating delay angle and the equivalent susceptance of fundamental wave. Through simulation, proving the rational interpolation has a better approximation and smaller difference.(4) Researching the three different ways of thyristor triggered mode, design a system which can achieve the thyristor indirect trigger using CPLD. Through experiment, proving this ways can improve the stability and anti-jamming capability of triggered pulse. It has high accuracy, high speed responsibility and small dispersibility.(5) Analyzing the anti-jamming technique in the hardware design and PCB welding,it gives some solutions. At the same time, testing and debugging the some parts of the hardware modules in the laboratory, and gives the results of testing.