Application of Direct Control Technique for Electric Power Steering System Assisted by Brushless DC Electric Motor

For several decades, electric power steering systems have progressively replaced traditional hydraulic-assist steering systems. Electric power steering of vehicles successfully competes with hydraulic boosters of similar purposes, showing high efficiency, energy saving and environmental friendliness. The primary function of electric power steering is to generate assist torque via an electric motor, thereby enhancing driving comfort. This paper presents the development of a brushless direct current motor control system using direct torque control without the need for flux linkage regulation. The rotor position is detected via Hall effect sensors, and the motor operates with a specific magnetic system configuration that eliminates the necessity for traditional flux linkage control. To mitigate current pulsations during phase commutations, a novel direct torque control algorithm for the BLDC motor is proposed. Extensive simulations are conducted in MATLAB/Simulink to assess the performance of the system. The results indicate that the introduced method in controlling the electric power steering provides more comfort to driver and provides a good real time control effect of driver's steering feeling.