Position detector for moving magnet type linear motor

摘要

In a moving magnet type linear motor including a stator with a plurality of coils placed in one direction and a mover with a permanent magnet opposed to the stator, a position detector detects the position of the mover. The position detector includes a magnetic body fixed to the mover. One or two or more coils are selected and a voltage is applied to the selected coil while a current or a voltage induced in a coil adjacent to the selected coil is measured, and the position of the magnetic body that changes in response to the position of the mover is determined based on the measured current or the measured voltage.

主权项

1. A position detector for a moving magnet type linear motor, the moving magnet type linear motor including: a stator with a plurality of coils placed in one direction; and a mover with a permanent magnet so placed as to be opposed to the stator, a magnetic field generated by applying a voltage to the plurality of coils of said stator causing said mover to move in said direction, the position detector detecting the position of the mover in the moving magnet type linear motor, the position detector comprising:
a magnetic body fixed to said mover; power supply control means for generating a magnetic field for position detection by applying a voltage to a coil selected on receipt of a command; measuring means for measuring a current or a voltage induced in a coil selected on receipt of a command; command means for giving a first command to said power supply control means intended to select one or two or more coils as a target of application of a voltage, and a second command to said measuring means intended to select a coil as a target of measurement of a current or a voltage that is adjacent to the coil to be selected by said power supply control means on receipt of said first command; and position determination means for determining the position of said magnetic body that changes in response to the position of said mover based on a measured value obtained by said measuring means, by controlling the command operation by said command means.