This paper presents the design, development, and performance evaluation of a single-phase microcontroller-based SCR (Silicon Controlled Rectifier) power control system employing a Zero-Crossing Detection (ZCD) technique for precise AC power regulation. The proposed embedded hardware architecture integrates a ZCD-based control unit, a bidirectional SCR driver circuit, and an SCR module with a power conditioning unit. The control algorithm, implemented on a microcontroller platform, performs precise zero-cross detection via hardware interrupts, computes the firing angle (α), and generates synchronized triggering pulses through optically isolated driver circuits. The system supports multiple operational modes, firing angle control, integral cycle control, and on/off control, enabling flexible load management. Experimental validation was performed using resistive loads and a 220 V, 42 W incandescent bulb. The results demonstrate accurate bidirectional triggering and stable load voltage control across firing angles from 0° to 180°, corresponding to delay times (td) of 0–10 ms. Notably, the measured RMS voltage, apparent power and perceived illumination reached their peak at α = 45°, confirming a non-linear relationship between the firing angle and output characteristics. The developed prototype provides rapid and stable power regulation between 0% and 100%, making it suitable for industrial heating and lighting systems. Future research will incorporate adaptive and soft-start control strategies to enhance operational efficiency and compatibility with resistive–inductive loads.
Karaduman et al. (Thu,) studied this question.