DC Motor Control with a Variable PWM Frequency

DC motors widely used, due to the easy controllability, inexpensive prices, durability and less maintenance requirements. Speed of DC motor can be controlled efficiently and effectively by changing the wideness of pulses. PWM frequency determines the controller performance and PWM duty ratio determines the speed. PIC 16F877A microcontroller is chosen due to inexpensive prices, simple development environment, serial interface, capture module and PWM module. The microcontroller takes the target speed from analog input, calculates the optimum P and I parameters according to the variations of the target speed, determine the PWM frequency and duty ratio as an output. Due to the optimum controller parameters and PWM frequency, system efficiency increases in slow speed variations, performance increases in high speed variations.