The Research On Hybrid DC Contactor For Railway Locomotive And Its Integrated Design

The DC contactor is a kind of electrical controller that is widely applied in railway locomotive. Its reliability and life-span directly affects the whole system's reliability and life-span. Electrical arc is generated when mechanical contactor is operated. The electrical abrasion cann't be avoided, however, the higher power is, the more electrical abrasion is generated. This is a primary factor that affects the life-span of high-power switch. To slake or weaken the effect of arc, the hybrid contactor is researched in this paper. The power electronic device and mechanical contactor are connected in parallel in hybrid contactor. It is controlled by logical circuit. While the mechanical contactor turns off, the electrical switch is loaded. And mechanical is loaded in stabilization. The hybrid contactor has a lot of advantage such as no arc, high reliability, pollution-free, explosion protection.The research of the hybrid contactor is very little in our country at present, and no product for railway locomotive. This paper accords to robust design with the customer's demand and the circumstance of the electromagnetic contactor. This paper researches the character of close time and release time about the electromagnetic contactor, selects the suitable power electrical device, and makes the hybrid DC contactor prototype by controlling circuit which makes use of the digital and analog circuit. This paper also accomplishes the design of parameter which belongs to drive circuit, isolated circuits, delay circuit, switching circuit, temperature protect circuit, and surge voltage and surge current protect circuit. To test the prototype's performance, this paper also has experiment on this contactor. Utmost current testing can prove that the contactor has the ability of four times over-current. Reliability life-span experiments can reflect the trend that is electronic life-span is basic direct proportion to machine life-span, and the contactor electronic life-span is very long. Standard test is made by product checking center of engine and vehicle of Ministry of Railway. And this proves the prototype agree the standard of TB/T2767-1996.Hybrid contactor is designed with modularization, just only to slake or weaken the effect of arc, and it cann't solve those problems such as the high power...