Wheel-slip Control Method for Seeking Maximum Value of Tangential Force between Wheel and Rail

Abstract

A method for reducing motor torque in proportion to wheel slip is applied to an inverter-driven electric locomotive. The motor torque at wheel-slip speed is less than the torque at the maximum tangential force or the adhesion force. A novel anti-slip control method for seeking the maximum value of the tangential force between the wheel and rail is proposed in this paper. The characteristics of the proposed method are analyzed theoretically to design the torque reduction ratio and the rate of change of the pattern between the wheel-slip speed and motor current. In addition, experimental tests are also carried out to verify that the use of the proposed method increases the traction force of an electric locomotive driven by induction motors and inverters. The experimental test results obtained by using the proposed control method are compared with the experimental results obtained by using a conventional control method. The averaged operational current when using the proposed control method is 10% more than that when using the conventional control method.

Recent trends in power electronics applications as solutions in electric railways

“…They are slip/skid re‐adhesion control, regenerative brake control under light load condition, and damping control for the DC‐side LC resonance. Slip re‐adhesion control is utilized to prevent the wheel slip during acceleration and wheel skid during deceleration . The speed and mechanical parameters with regard to wheel slip are defined as shown in Fig.…”

“…This manner is an appropriate for the case where one inverter controls several motors because precise slip speed is not required. On the other hand, the slip speed control method is sometimes utilized for locomotive traction system. In this method, the car body's speed must be precisely detected to detect the wheel speed.…”

“…Outlook of battery-powered EMU type EV-E301 of JR east (left) and outlook of the world first fuel-cell-powered railway vehicle developed by Alstom in commercial service in Germany (right) Traction wheel and traction motor with gear[46] …”