Disclosed is a sensorless control system for a permanent magnet synchronous machine. The sensorless control system includes a counter electromotive force estimation unit configured to estimate a counter electromotive force using a phase voltage reference applied to an inverter and a phase current applied from the inverter to the permanent magnet synchronous machine, and a speed estimation unit configured to estimate an angular velocity and an electrical angle of a rotor of the permanent magnet synchronous machine, and the counter electromotive force estimation unit according to one embodiment of the present disclosure may maintain robust performance at a low speed by modifying some portion of a conventional Luenberger observer.