Abstract

This project aims to control the speed and direction of a DC motor in four quadrants: clockwise, counterclockwise, forward braking, and reverse braking. An H-bridge motor drive IC is used to switch the motor’s polarity based on user inputs via four control switches. A slide switch enables alternative directional control. A 555 timer generates PWM pulses for speed regulation, while relays manage polarity changes and braking. In regenerative braking, the motor generates reverse Ftorque for instant stopping. The four-quadrant control is achieved by varying the duty cycle of the PWM signal and switching polarity using the H-bridge IC. The paper provides an overview of DC motor operation, explaining key components and working principles. It discusses the importance of four-quadrant operation, including motoring (forward/reverse) and braking (regenerative/plugging). Various control strategies such as armature voltage control and field flux control are examined for their efficiency. Applications in electric vehicles, robotics, and industrial automation are explored, demonstrating the versatile use of DC motors in modern engineering.