Parameter independent phase tracking method for sensorless control of PWM rectifiers

In this paper a new parameter independent sensorless control strategy for a voltage oriented controlled (VOC) three phase pulsewidth modulated (PWM) power supply rectifier is presented. This control method requires neither the measured AC-line voltages nor any accurate circuit parameters for estimation purposes. Furthermore there is no need for additional test signals. There are no additional hardware requirements with respect to the standard drive inverters available in the market which usually are not equipped with AC-side voltage sensors. It will be seen that the calculation demand for the sensorless approach is negligible in comparison to the requirements for the control itself. This approach makes use of the slow varying AC-line voltage - the sample frequency of the inverter is at least ten times higher. The principle of the proposed method is ex-plained, and its effectiveness is proven experimentally.