Neutral section passing strategy preventing inrush current for electric railway solid-state transformers

This paper proposes a neutral section passing strategy for preventing the inrush current of an electric railway vehicle (ERV) with a solid-state transformer (SST). This inrush current is not generated when the ERV passes the neutral section by maintaining a dc-link voltage at a constant level that is higher than the peak voltage of an electric railway feeder using regenerative energy from the ERV. Depending on the position of the ERV, the control strategies and modes are changed. When the ERV passes the neutral section, the regenerative energy from the ERV charges the dc-link voltage. A dc–ac converter that operates a traction motor takes charge of the dc-link voltage control in the regeneration operation. Simulation results show that the proposed strategy can protect the SST from inrush current when the ERV passes the neutral section. Experiments have been carried out with a scaled-down prototype. Experimental results verify the performance of the proposed neutral section passing strategy.