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

This paper presents a new current control method for three-phase pulse width modulation rectifiers with active power factor correction (PFC). Conventional three-phase PFC control requires sensing of at least two input phase currents. Since the input line must be isolated from the control circuitry, current transformers or Hall effects current sensors are required for sensing the phase currents, which are bulkier and more expensive than resistive current sensors. Such electromagnetic current sensors are also difficult to integrate with the rest of the control circuitry, representing a major barrier for low-cost integrated PFC control development. The proposed 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 sensed signal can be directly used by the control circuitry without isolation or level shifting. 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.