Invention Grant
US09577562B2 Method and apparatus for back electromotive force (EMF) position sensing in a cryocooler or other system having electromagnetic actuators 有权
用于具有电磁致动器的低温冷却器或其他系统中的反电动势(EMF)位置感测的方法和装置

Method and apparatus for back electromotive force (EMF) position sensing in a cryocooler or other system having electromagnetic actuators
Abstract:
A method includes driving a component in an electromagnetic actuator back and forth during one or more cycles of the actuator, where the actuator includes a voice coil. The method also includes identifying a back electromotive force (EMF) voltage of the voice coil during at least one of the one or more cycles. The method further includes determining whether a stroke of the component is substantially centered using the back EMF voltage of the voice coil. In addition, the method includes, based on the determination, adjusting one or more drive signals for the voice coil during one or more additional cycles of the actuator. Determining whether the stroke of the component is centered could include determining whether the back EMF voltage of the voice coil is substantially maximized or determining whether times between extremes in the back EMF voltage are substantially equal.
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