Miniaturization Research Of DC Boost Circuit For Railway Vehicles Circuit Breaker

With the rapid development of economic and social progress, the electrified railway construction of our country increases year by year. Electric locomotive circuit breaker which is the core of the railway secuirity, its reliability and security has been closely watched. At present, pneumatic mechanism are widely used in electric locomotive circuit bareaker, the volume of operation mechanism is large; high noise; low reliability; prohibitive cost of maintenance and more potential secuirity risk; If the operation mechanism break-down, the whole system collapse very easily. In this paper, the circuit breaker is armed with new type of electricmagnetic operating mechanism and controled by singel-chip computer. DC boost circuit in control system supplys power for electricmagnetic operating mechanism. The objective of this paper is to research the problem of lowing the volume of DC boost circuit.In the special occation of high-speed rail, in order to insure the breaker acts rapidly and accurately when the train accross the phast-seprating section, the voltage value and the time rising to setting voltage are both definitely limitied. In this paper, the factors which effect the charging time of capacitor of Boost Chopper was researched by emulation analysis mode, design the core element-conductor of Boost Chopper. Mathematical simulation of heating situation of the conductor is completed by using multidiscipline coupled-field software named COMSOL Multiphysics. Selecte the less volume conductor to met the reqiurments of perfamance and temperature rising by comparing the temprature rising results.Choose power electronic simulation software PSIM to emulate the charging time of the capacitor in Boost Chopper; Respectivly studied the influnce of duty cycle, inductance and frequency on capacitor charging time in boost circuit. Select the inductance on conditions of frequency is 4kHz; variational duty cycle and metabolic inductance to satisfied the requirement of charging time, at the same time, simulated the capacitor voltage wave and circuit wave. Designed the inductor according to the simulation results of the inductor circuit and inductance.In term of minimizing the volume of induactor,choose the smaller iron core as far as possible. The major processes of using COMSOL Multiphysics to simulate the heating situation contain following steps: Build models, Applied load, Solve and check results. Select the conductor by synthetically consider the capacitor charging time; conductance; inductor circuit; volume size of the conductor and inductor temprature, The optimal reactor is the one with the lesser temprature rise.