Railway 25hz Signal Power Screen

Railway 25Hz signal power supply panel is the most important equipment in electrical railway system, it provides two different magnitude 25Hz AC outputs: 110V and 220V.This paper details the design of railway 25Hz signal power supply panel hardware circuit from four parts. First part describes PFC circuit, PFC can increase the power factor of front end and reduce the harmonic pollution brought by the power supply, and it also provide stable DC voltage; The second part contains DC/DC converter, electrical isolation between input and output, two outputs are realized. The third part introduces inverter circuit, it provides two needed sine output voltage. And the last part is about parallel operation current sharing technique, parallel operation greatly improves system stability.Two generation schemes of SPWM for the unipolar inverter and their respective control technique are introduced, then detailed analysis is followed. Simulation and experimental results shows that dual-side SPWM generation scheme is more preferable.Moreover, this paper bring forward an automatic master-slave selection parallel operation technique. Hot plug-and-play inverter parallel operation is realized.