Automatic power factor improvement using microcontroller

Abstract

The chief objective is to improve the power quality by continuously monitoring the load power factor. When the load power factor falls below a certain value it results in the increase of line current, resulting in more line loss and greater voltage drop. Thus, the aim is to inject capacitances of required values when the power factor falls below the specified level. Primarily, a signal of pulse width proportional to the phase difference is generated. From the ON time period of each pulse the power factor can be determined. The exact value of the capacitance to be injected is then found out using some mathematics. Finally, the value of capacitance, so obtained, is to be approximated with the standard values of capacitance. Micro-controller will switch all the capacitors, which taken together is very close to the exact value of the capacitance.