A Study on Improvement of Control Performance of Electric-Continuous Variable Valve Timing System Using BLDC Motor

This paper deals with the control performance improvement of the E-CVVT system using BLDC motor. Each element of the E-CVVT system is implemented by mathematical modeling. The response performance of the E-CVVT system is verified based on the camshaft motion, cam profile, BLDC motor and mathematical model of the controller. In order to confirm the speed change of the valve due to the rotation of the camshaft, a cam profile is used to express the up and down motion of the valve as a curve. To analyze the operating characteristics of the E-CVVT system, a BLDC motor is modeled using Simulink. The E-CVVT system controls the phase angle of the camshaft. When the E-CVVT system sets the target phase angle, the motor controller generates the optimal motor speed command. The response speed depends on the setting of each PID parameter, which changes the phase of the camshaft. Finally, we confirmed the improvement of the E-CVVT system response performance according to the change of the PID parameter.