Sensorless nonlinear control for a three-phase PWM AC-DC converter

The main objective of this paper is to implement a nonlinear control for a PWM voltage source converter with a reduced number of sensors. For this purpose an input-output feedback linearization control strategy is firstly implemented in order to control both the line current and the DC output voltage. Next, an estimator of the AC mains voltage is implemented so as to reduce the number of the requested sensors, to avoid the undesired noise, and to minimize the converter´s cost. The efficiency of the proposed control law and estimation method is next validated through simulation results. Consequently, load independent unity input power factor operation and a perfect tracking of the DC bus voltage waveform are achieved even without using mains voltage sensors.