ABSTRACT

Nurhayati Jabir, The Phase Locked Loop (PLL) Mechanism of a Direct Current (DC) Motor Speed Control System (supervised by Rhiza S. Sadjad and Muhammad Tola)

The purpose of this research is to develop a fairly accurate numerical model of a Direct Current (DC) motor speed control  system using the Phase Locked Loop (PLL) mechanism. A 2500 RPM, 3 kW DC motor (RS type # 718997) is taken as an example. The numerical model is developed using the SIMULINK faciity of MATLAB.

Without any closed-loop control system, the load regulation of the speed turns out to be ranging from +0,32% to +1,44% for the load variation ranging from +10% to +100%.

The PLL mechanism is accomodated to the system by adding a 1:N transmission gear system, an optical tachometer, a reference pulse generator, a Phase Detector, a Proportional-Integral-Derivative (PID) controller and a Low Pass Filter. The performance of the motor speed control system is evidently improving. Now, for the load variation ranging from +10% to +100%, the load regulation is only ranging from +0,04% to +0,48%. The dynamic performance of the motor speed control system is also significantly improving in terms of its maximum overshoot and its  settling-time.