Method to design control system of traction inverter of DC-electrified railway vehicle for an increase in regenerative brake power

This paper proposes a method to design the control system of a traction inverter for the purpose of an increase in regenerative brake power. In a DC-electrified railway system, it is possible to transmit more regenerative brake power to an accelerating train by maintaining a higher DC input voltage of the regenerating train. On the other hand, regenerative brake control of a traction motor according to the DC input voltage of a traction inverter is generally applied. With regard to the proportional gain of this control system, the higher gain contributes to an increase in the DC input voltage in regeneration. However, there is a possibility that the control system can become unstable by applying higher gain. Considering the trade-off between the energy saving effect and the stability, this paper proposes a method to design the maximum gain that keeps the traction circuit stable. At first, a linearized model for the proposed method which includes the model of the traction system, its control system and DC feeder circuit is introduced. Further, this paper reveals that the proposed method keeps the control system stable by using real scaled experiments.