Design of Safety Drive Control Unit for AC Signal without Relay Contact

Aiming at the deficiencies of the existing AC signal control system with relay interlocking, this paper introduces a safe driving control unit of AC signal without relay contact. Based on the principle of distributed control and the working principle of dual CPU, it could realize distributed control trackside signal of the interlock-zone and stations and safe drive signal. And, it uses the high frequency and high voltage characteristics of power electronic devices to realize the miniaturization and full-electronic control of the signal control system. At the same time, the control unit solves the problems of current surge when the relay is started, complex control circuit and high maintenance cost. Experiments show that the unit runs stably and has strong practicability. It will play an important role in the distributed trackside control system.