Sensorless sine-wave controller IC for PM brushless motor employing automatic lead-angle compensation

This paper presents an advanced sensorless permanent magnet (PM) brushless motor controller integrated circuit (IC) employing an automatic lead-angle compensator. The proposed IC is composed of not only a sensorless sinewave motor controller but also an isolated gate-driver and current self-sensing circuit. The fabricated IC operates in sensorless mode using a position estimator based on a sliding mode observer and an open-loop start-up. For high efficiency PM brushless motor driving, an automatic leadangle control algorithm is employed, which improves the efficiency of a PM brushless motor system by tracking the minimum copper loss under various load and speed conditions. The fabricated IC is evaluated experimentally using a commercial 200 W PM brushless motor and power switches. The proposed IC is successfully operated without any additional sensors, and the proposed algorithm maintains the minimum current and maximum system efficiency under 0 N•m to 0.8 N•m load conditions. The proposed IC is a feasible sensorless speed controller for various applications with a wide range of load and speed conditions.