Method and apparatus for back electromotive force (EMF) position sensing in a cryocooler or other system having electromagnetic actuators
US9577562B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 5, 2014 |
| Grant date | Feb 21, 2017 |
| Priority date | — |
| Expiry date | Dec 5, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F2007/1866
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.