Three phase pulse width modulated voltage source rectifiers are widely used in uninterruptible power supply and motor drive applications due to their low input current THD, adjustable input power factor, and bi-directional power transfer characteristics. In this paper utilization of this type of rectifier at the front end unit of an industrial type uninterrupted power supply is discussed. DC bus voltage is controlled through two high gain PI controllers. Sinusoidal Pulse Width Adjustable Triangle Wave Comparison for switching (SPWM) was selected as the control method. Unity power factor has been attained at the input along with very low THD values.