Application of Eddy Current Braking in Automobile Using Rotating Magnetic Field From Stationary Poly-Phase Windings

Abstract

 Automobile braking by eddy current induction using rotating magnetic field has been studied. A conducting brake disc rotates between the poles of an electromagnet. There is no contact. The electromagnetic field comes on when the brake is applied and eddy current is induced in the conducting brake disc to effectuate retardation. The brake disc is coupled to the road wheel so that retardation of the brake disc transmits directly to the road wheel. The eddy current braking torque is a measure of the braking power. The braking torque varies directly as the relative speed between the conducting brake disc and the eddy current brake magnetic field. The braking torque is studied under three main conditions. These are when the brake disc and the magnetic field rotate in opposite directions, when the brake disc and the magnetic field rotate in the same direction and when the wheel is stationary with only the magnetic field rotating. Braking performance is studied in terms of stopping a vehicle, slowing and preventing motion. Results show that stopping and slowing down are achieved when the magnetic field rotates opposite the direction of the brake disc rotation. For stationary wheel, motion will not occur as long as the torque which tends to be tractive is counterbalanced by friction at the wheels and the vehicular mass inertia. Modelling and simulation in this study was done using Matlab - Simulink software.