Research Of Harmonic Free Orthogonal Controllable Reactor Based On Current Type Converter

With the development of power system, especially the development of long distant transmission technology, arc suppression coil and reactive power compensation technology, higher demanding for controllable reactor has been received. At present, controllable reactor has a lot of types, and each type has its own advantages and disadvantages. In this paper, the author did research on orthogonal controllable reactor, which has advantages of easy control, low harmonic, and so on.Based on the analysis of the principle of orthogonal controllable reactor, this paper made detail research on the control characteristic and harmonic characteristic. Using the method of three dimensional Reluctance Network Analysis, the simulation model has been built. And detail analysis have been made using the simulation software of Saber,the simulation model is more propitious of further analysis and design.Although the orthogonal controllable reactor has ascendant performance, the harmonics it produced goes beyond the harmonic criterion of power grid. This gravely influences its widely applied in industry. Therefore, harmonics elimination has become one of the pop topics of orthogonal controllable reactor research. Compared with several harmonics elimination methods, this paper proposes a simple harmonics elimination method– harmonic current injection. And the principle of harmonic elimination is elaborated, and validated using simulation. In allusion to the special structure of orthogonal controllable reactor, this paper proposed two different types of structure: the voltage type and current type harmonic free orthogonal reactor. Further more, comparison has been made of the two types.This paper designed the control system of current type harmonic free orthogonal controllable reactor due to its superiority in performance. The design mainly included the calculation circuit of injunctive current and the current tracking control circuit. In the calculation circuit of injunction current, the injunction current contained not only harmonic part of working current, but also control signals for maintaining DC current invariable and for restraining the resonance of output filter. In this paper, the DC current control strategy was derived from the active power balance point of view, and the virtue damping resistor was put into controller to restrain oscillation. The simulation result validated the correctness of the control system.Simultaneously,the design method of main circuit of current type harmonic free orthogonal controllable reactor has been analyzed. The design included the Pulse Width Modulation converter, and its output filter, the circle numbers design principle of the working windings, control windings and compensation windings.In this paper, the author made deep research on the current type harmonic free orthogonal controllable reactor, and designed the whole system. Through simulation method, it could be seen that the current type harmonic free orthogonal controllable reactor could show good control characteristic, at the same time, reduce the harmonic in a large range.