Estimation of Number of Cores for Preventing Common-Mode Inductor Saturation in Railway Traction Inverters

In the traction system of rolling stock, common-mode (CM) voltage is over 500 V, so inductors that suppress CM current are prone to saturation. To prevent saturation, inverter needs many numbers cores inside inductors, but required number has been determined empirically. This paper proposes a method calculate approximate nanocrystalline avoid saturation in railway inverters without circuit simulation. Using only capacitance motor and core characteristics on datasheet, maximum flux density inductor calculated. Comparing calculated results with measured 1500 V DC indicates proposed can better identify occurrence than methods based presented literature. Furthermore, for entire range from 3000 minimum which prevented by calculation shown be reasonable agreement simulation results.