Multisystem Rolling Stocks

Multisystem rolling stocks employs a traditional configuration for the input stage, which is based on the line frequency transformer and four‐quadrant converters that are tuned to comply with electromagnetic compatibility standards. It is necessary to run the main transformer with different voltage levels and different frequencies, as well as use it as an inductor in the systems. This chapter focuses on the operation of the following multilevel transformers: multivoltage and multifrequency transformers and power electronic traction transformers (PETTs). Multilevel structures allow higher voltage to be adopted in DC section, achieving the goal of increasing the transmittable power with equal transmission losses. The chapter then considers two boost converters whose absorbed current waves have a phase shift of a generic angle. The logical choice for controlling the 4Q converter follows current tracking logic, for which the modulation index m does not appear directly in the control algorithm.