Energy Optimization of Brushless DC Motor in Electric Power-Assisted Steering

In an electric power-assisted steering (EPS) an electric motor is controlled to provide assistance in vehicle steering and to enable various steering feels. To optimize energy consumed by a column-type EPS equipped with a brushless dc (BLDC) motor the author designs two controllers as needed. Firstly a controller to generate driver torque is developed based on nonlinear adaptive regulation method using the mathematical model of EPS. The second controller is a PID motor controller that is applied to produce assistance torque for desired energy saving. The trade-off between driver’s comfort and energy consumption is demonstrated using Matlab simulation results. In electric vehicles (EVs) where electrical energy is limited the control scheme introduced here is expected to fit perfectly.