On braking efficiency of urban electric transportation systems based on power electronics

The paper deals with specific matters related to the electric braking processes in urban transportation systems that use power electronics (choppers). One presents theoretic aspects concerning the braking processes at urban electric traction d.c. motors, including the cases when power electronics are used. Problems related to the designing stage and to the optimum solution determination are addressed. The advantages of using a mixed electric braking system that use both resistive and respectively regenerative braking are emphasized. The designed and realized equipment are tested on stand. In the end one presents the efficiency of the adopted solution as revealed by tests on a tram. Aspects concerning both the resistive and respectively regenerative brakings are presented.