A readhesion control method without speed sensor for electric railway vehicles

Railway vehicles have tractive force by rolling contact between wheel and rail. When the friction coefficient between wheel and rail is small, there are some cases where wheel slips or skids cause running difficulties. Therefore, wheel slips or skids are now actually studied. Electric vehicles fed by inverters, and traction motors vector control have come into wide use, and vector control without a speed sensor is at a trial stage for commercial trains. Conventional re-adhesion control methods have made use of speed-sensor (pulse generator) signals. When vector control without speed sensor is used. It is desirable not to use speed sensors for re-adhesion control, and to maintain unchanged performance. We propose a method of slip detection without speed sensor by focusing on the current of each motor. The effectiveness of the proposed method was verified by simulation results and running tests using Shinkansen train.