Hardware Design Of Static Var Compensator Based On DSP

The hardware of the DSP-based Static Var Compensator(SVC)is introduced in this paper. First the principle of Thyristor Controlled Reactors (TCR) type SVC is discussed. At the same time, the mechanism of SVC to control voltage and improve stability of the system of SVC is analyzed. For the target of compensation, the whole system model is established.Throughout the whole hardware design, the main circuit relatively simple, the main working is determining the parameters of analog transmission line parasitic reactor, compensation reactor, thyristor compensation reactor. The control system of TCR-SVC is the key of device and is also the key technology of SVC. The software and hardware of the SVC controller are designed in this paper. The hardware includes the following parts. First is the power circuit. Second is the DSP control circuit. In order to improve the accuracy of the signals, analog filter circuits which filter high-order harmonic are designed to filter the signals which are given befor DSP. Third is the forming of thyristor trigger pulse's circuit, the accuracy and reliability of thyristor's trigger control angle will directly affect the reactive power compensator. It is one of the main research contents. It mainly includes synchronous circuit, converter circuit about voltage and frequency, sampling circuit, protection circuit, pulse forming and amplifying circuit and other peripherals controlling and driving circuits. In addition, the convert circuit about voltage and frequency changes the common method taken by PLL circuit into integrated circuit in this paper, and high convert precision is verified from the experiments results. In the fields of software, CPLD is adopted to design the thyristor's trigger pulse under the state of unbalanced three-phase circuit, hence, the current situation that we are unable to realize the separation compensation is overcome. By changing the analog voltage signal which input DSP, the continuous changing of thyristor's trigger angle in TCR is achieved, and the reactive power compensation about the whole system is obtained.Based on the design of hardware, tests are carried out about the prototype. Finally, the results of the experiment are analyzed in detail, and the rationality of the design by means of contrast between digital simulation and experimental results is verified.In the end, we sum up the insufficiency of the whole system and predict as well.