Abstract



The advancement of Power Electronics has brought progress in the control and conversion of electric power. Power electronic systems have good efficiency, flexibility of control and high reliability. Motor drives application is one classic application. Motor drives has the advantage of adjustable characteristic like torque-speed, speed-current by using control technique. With DC motor, precise control of speed that is required in many industries can be achieved. An efficient speed controller for a Permanent Magnet Direct Current (PMDC) motor for an X-ray system using PIC18F4620 is presented. An H-bridge feeds the PMDC motor. The PIC (Peripheral Interface Controller) generates the necessary Pulse Width Modulated (PWM) gate pulses for the H-bridge switching devices for driving the PMDC motor. By controlling the duty cycle of the PWM gate signals, the motor armature voltage is controlled and the motor speed is adjusted. Reliability of the controller is demonstrated through Accelerated Life Testing (ALT). ALT includes test such as Highly Accelerated Life test (HALT) and Highly Accelerated Stress Test (HAST) which are used to test the robustness and ruggedness of the product.