Precise Speed and Torque Control for AC Traction Pure Electric Braking System in Low Speed Range

Abstract

This paper describes a possibility to increase the operation range of railway's pure electric braking system at low speed range. Since low-resolution speed encoders are normally installed, precise speed information is unavailable at low speed. An estimation scheme called instantaneous speed observer is introduced to estimate the speed for precise torque and speed controls. The stability of the system is analyzed by multirate sampling theory and digital control theory. Several simulation results and experiments positively show the improvement of speed estimation and the possibility to extend the operation of the pure electric brake.