The Simulation And Parameters Optimization For The Breaking Characteristics Of Novel Medium-voltage DC Hybrid Circuit Breaker

As very important equipment for control and protection in the DC power system, theDC circuit breaker is not only the difficulty but also the focus concerned. The DC hybridcircuit breaker(HCB) is a new circuit breaker integrating the advantages of mechanicalcircuit breaker and solid state circuit breaker, it has wide application prospects in the fieldof low-voltage and medium-voltage level. Improving the interruption performance,expanding scope of use, and pursuing the miniaturization are currently the developmentdirections of HCB, at the same time, the electrical parameters of HCB have a great impacton its performance, size and cost. Therefore, the studies should be carried out on electricalparameters optimization of Novel DC HCB, which has a very important significance toguide the design of circuit breaker.In this paper, a novel HCB based on two vacuum circuit breakers and power diode isintroduced to be the research object, and then the operating principle of the topology isanalyzed. According to the characteristics of the Novel HCB, the vacuum circuit breakermodel and diode model are developed in the MATLAB, among them, vacuum circuitbreaker model can reflect three-stage working process: before the contacts open, thecontacts open until the current becomes zero and the dielectric recovery process; powerdiode model can reflect the turn-on and turn-off working process. On this basis, the circuitsimulation model of the Novel HCB is developed, while the short-circuit currentinterruption process is simulated, the simulation waveforms verifies the accuracy of themodeling.According to the characteristic of DC power system on ship, an equivalent model ofthe system is developed, as well as the mathematical model of the interruption process.Based on5kV/4000A-100kA HCB, the impact on converter process and dielectric recoveryprocess by the oscillation commutation circuit parameters including the capacitance value,the pre-charge voltage value, the inductance value, the resistance value is researched. Thenthe optimization scheme is put out, which means basing on the expected optimizationobjectives and formulas, establishing the objective function and the constraintscorresponding, getting the optimized result by using the algorithm.Lastly, minimum values of the capacitance and inductance of the oscillation circuit areobtained to be the optimization target in this paper. examples of Calculation andcomparison of simulation show the correctness and feasibility of the optimization scheme,the scheme can be used as the design and optimization method of the same type of HCB.