Micro controller based Power Factor Correction

Abstract

This paper presents the simple and low-cost design of an automatic power factor correction (APFC)
system for single-phase domestic loads. The proposed design uses TRIACs to switch the capacitor banks
in order to correct the power factor of inductive loads. TRIACs are more effective than electromechanical relays and hit the high-performance benchmarks. An Arduino board controls the switching of
TRIACs. The Arduino is programmed to non-stop monitor and calculate the power factor of the
connecting load by sensing the signal from CT, PT and Zero Cross Detectors (ZCDs), and keep the power
factor of the load above the reference value (0.95) by appropriately energizing the capacitors in parallel
to the connecting load through TRIAC switching. The value of power factor before and after improvement
is displayed on LCD. The hardware prototype of the proposed APFC design is also developed to validate
its operation. The satisfactory and acceptable results of the APFC system testing have confirmed that the
suggested design yields a reliable output and can be further used in any single-phase practical
application to ensure the power factor close to unity.