Improving INFORM calculation method on permanent magnet synchronous machines

This paper reports advances in sensorless rotor position estimation in motor control of electronic power assisted steering systems (EPAS). A systematic calculation error was discovered in the INFORM - a saliency based sensorless rotor position estimation method, - when it was applied to permanent magnet synchronous machines (PMSMs). A solution was found to correct the angle error of the measurement which was introduced by the PMSM.