This paper presents the design and implementation of a simple control system for three-phase high power factor boost rectifiers in power-factor-corrected online UPS applications. The design and simulation of the control system are performed in Simulink using Texas Instruments DSP tools as the controlling units and the PLECS circuit models as the power converter unit, and then the verified design is converted into a DSP code to be implemented in a real DSP chip. The boost rectifier stage is realized as six-switch IGBT based PWM converter. Performance of the controller developed in Simulink platform by emulation method is experimentally verified. Consequently, the results confirm that the proposed controller achieves high power factor at the input and overall good dynamic response for the boost rectifier under sudden load and input voltage variations, and also demonstrate the applicability of the design methodology presented in the paper.