Automatic power factor correction device reads power factor from line voltage and line current by determining the delay in the arrival of the current signal with respect to voltage signal from the function generator with high accuracy by using an internal timer. This time values are then calibrated as phase angle and corresponding power factor. Then the values are displayed in the LCD modules. Then the motherboard calculates the compensation requirement and accordingly switches on different capacitor banks. This is developed by using Microcontroller.
this proposed system the time lag between the zero voltage pulse and zero current pulse duly generated by suitable operational amplifier circuits in comparator mode are fed to two interrupt pins of the microcontroller. The microcontroller used is of 8051 family. It displays the time lag between the current and voltage on an LCD. The program takes over to actuate appropriate number of Relay (anti-parallel SCR’s) at its output in series with either an inductor or a lamp or shunt capacitors into the load circuit to derive the power factor of each type of load for display.
Watch on You tube : Power Factor Correction