Abstract: Controlled power is a fundamental prerequisite of various sectors. A scheme of microcontroller based firing angle control, using AT Mega 328 MCU & associated hardware circuitry is designed. Basic idea is to achieve reliable, consistent control that will result in improved performance of converter. Set-up consists of ATmega-328 controller, LCD display for displaying firing angle, transistorized conditioning circuit, main rectifier module and input from user in the form of analog voltage for firing angle control. Integration of these modules will result in full controlled converter with superior performance over other ordinary control techniques. Design, development, testing, and installation of a firing controller for a tri phase thyristor rectifier. AT Mega 328 microcontroller is used as the firing controller. This IC chip provides logical input and output, analog-to-digital conversion, timer for the delay counting, and various interrupt vectors for timing. The software algorithm consists of the detection of the zero crossing of the synchronization voltage to start the timing of a period. A special test is programmed to control the value of the firing angle. The design develops triggering circuit of 3-phase, 6-pulse, ac to dc controlled converter using AT Mega 328 microcontroller. The microcontroller will generate six equidistant, synchronized triggering pulses for the converter which finds application in power systems (high voltage DC transmission) and industrial drive systems. The controller is required to sense the input voltage and generate the required six trigger pulses irrespective of the variation of the mains frequency and to control the delay angle of these signals equally to control the DC output voltage.
Keywords: Microcontroller, AC/DC converter, Synchronization technique, gate triggering technique, DC motor.