A simplified position control of a transverse flux type linear synchronous motor using hall sensors

For position feedback control in long linear synchronous drives, high-resolution sensors such as linear encoders are often expensive for industrial applications. Furthermore, their fine precision comes along a higher sensitivity to contamination and disturbance. We propose an economic position sensing method which uses two Hall sensors for position control of long linear synchronous motor drives where field flux distribution can be approximated to sinusoidal. We obtain position signal from the Hall sensors. Two methods to derive speed signal from the position signal given by the Hall sensors have been compared. The first is an approximate differential operation of position with low-pass filter. The second is application of state observer including external load force in its state variables. In addition, the performance of the cascade position control feedback is verified to satisfy technical requirements in numerical studies.