Control of Three-Phase PWM Rectifiers Using a Single DC Current Sensor

Abstract-This paper presents a new current control method for three-phase pulse width modulation rectifiers with active power factor correction. Conventional three-phase PFC control requires sensing of at least two input phase currents. Since the input line should be isolated from the control circuitry, current transformer or Hall effects current sensors can be used for sensing the phase currents, these are bulkier and more expensive than resistive current sensors. That type of electromagnetic current sensors are also difficult to integrate with the rest of the control circuitry, it is a major barrier for low-cost integrated PFC control development. The new current control method solves these problems by using only the dc-rail current as the feedback signal.The dc-rail current can be easily sensed by a shunt resistor, and the output signal can be directly used by the control circuitry without isolation.The control method is developed based on a nonlinear average current control principle and avoids the steady-state phase error of conventional linear PI control. Key words- Current sensing, nonlinear current control, power factor correction, PWM rectifiers. I