Study On Fast Response Magnetic Valve Controllable Reactor

In the field of reactive power compensation, as a novel dynamic device, magnetic valve controllable reactor (MCR) has attracted increasing attention owing to its simple manufacturing process, low cost, and high reliability. However, the problem of slow response of MCR has limited its application in many occasions. Based on this problem, the fast response MCR is studied in this paper.This paper briefly introduces the structure and principle of MCR and its mathematical model is derived by simplifying the magnetic circuit. The electromagnetic equations of different five working operations are listed. By adopting iron core small slope curve model and electromagnetic equation of MCR, the response characteristic is analyzed. The estimated equation of regulation time is obtained. Based on that, the slow response problem of MCR is introduced. In the field of reactive power compensation, the fast response characteristic is required in many occasions. Therefore, a fast response circuit including excitation capacitor is designed. Its topology includes fast excitation branch, self-coupling excitation branch and fast demagnetization branch. The principle of fast response MCR and control scheme of controlling switch in circuit are given.The design method of MCR is the focused research. By the reference of transformation design theory, the design process of MCR is obtained. The calculation formulas of core, winding, magnetic valve and tap ratio, loss calculation are obtained. Based on the problem of complexity of electromagnetic calculation, the selection strategy of excitation capacitance and its initial voltage are analyzed. A GUI output interface auxiliary calculation software is developed. Electromagnetic calculation results of fast response MCR are given with the use of software. The rating voltage is 10kV and the capacity is 300kVA. The controller of fast response MCR is developed. The main control chip is TMS320F2812. The structure of hardware and software flow pattern is introduced in detail. It includes signal modulating circuit, synchronization voltage circuit, thyristor drive circuit, IGBT trigger circuit, main procedure and interrupt service procedure. The discharge time of excitation capacitance depends whether the two end voltage is zero. The controlled switch is controlled by switching value of controller. Based on that, the model of routine excitation and fast excitation is built by Matlab. The response characteristic curve of working current and controlling current under these two conditions are compared. The results show that response speed of fast excitation MCR is largely improved. Finally, the physical simulation test platform is built and prototype test is made. The control and response characteristic are tested. The experimental results verify the feasibility and correctness of this set fast response MCR.