This document reviews various techniques for power factor correction in brushless DC motor drives, including SEPIC converter, isolated-zeta converter, boost converter, four quadrant operation, Landsman converter, and BL-CSC converter. It discusses the operation and simulation results of each technique, comparing their performance in terms of percentage total harmonic distortion and power factor. The boost converter and isolated-zeta converter are highlighted as suitable for low power applications due to their ability to operate in discontinuous conduction mode with a single voltage sensor. Maintaining a high power factor is important to improve power quality at the AC supply.