Sensorless DTC propulsion control of PM LSM vehicle

This paper presents a sensorless direct torque control (DTC) propulsion method of a 1/2-scale controlled-PM linear synchronous motor (LSM) Maglev model vehicle which is not levitated and used as a PM LSM vehicle supported by the wheel. This is the first experiment for DTC to be applied to linear propulsion without position and speed sensors, which is one of the most important problem to be solved in practical applications. DTC can control directly thrust force and the stator flux linkage by the switching commands of the six inverter-arms with a switching table. The DC voltage and three phase current are adapted instead of position and speed sensors. A 3-m-propelling-motion experiment with a constant speed of 0.4 m/s shows that the demanded position and speed can be traced accurately even though there is a strong detent force.