Abstract:Based on the relationship between the braking torque of eddy-current retarder and its excitation current, the PWM technology was applied to realize the stepless modulation of the braking force of eddy-current retarder in order to make a vehicle to run downhill at constant speed. The running conditions of the downhill vehicle were analyzed. With the vehicle speed and inertia force caused by the instantaneous acceleration as the control target of the eddy-current retarder braking torque, the control tactic of the eddy-current retarder braking torque was proposed, and the control process was described. The calculation results of the different original running conditions of an actual vehicle show that the vehicle can run down the slope at the steady targeting speed with the real-time control of braking torque of eddy-current retarder.