This work aims to propose speed sensorless control for the motor drive system equipped with the LC filter, especially for the long cable transmission scenario or high switching frequency inverter-based system. To this end, a novel EMF modeling based on the weighted current between the filter inductor current and motor stator current is proposed, which makes the third-order system equivalent to the virtual first-order virtual plant. In this case, the existing strategies for EMF observation can be directly employed based on the proposed EMF modeling. This work thus solves the sensorless control challenge for the LC-filtered motor drives and the measurement of motor terminal voltage is avoided.
