Motor driver circuit for resonant linear cooler
US5032772A · kind A · utility
Inventors
Key dates
| Filing date | Dec 4, 1989 |
| Grant date | Jul 16, 1991 |
| Priority date | — |
| Expiry date | Dec 4, 2009 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF25B2309/1428
- WIPO fieldThermal processes and apparatus
- WIPO sectorMechanical engineering
Abstract
A direct current powered, linear resonant cryocooler having a compressor in which the piston is reciprocated by a linear motor at substantially resonant frequency and the length of stroke of the piston is varied as a direct function of cryocooler temperature. There are two control loops, a temperature control loop and a voltage control loop which is independent of the temperature control loop. In the temperature control loop, temperature is sensed at the cryocooler or expander and the temperature signal is compared with a reference temperature signal to produce a temperature error signal or voltage. The voltage control loop controls motor voltage. As input to the voltage control loop, the linear motor voltage is fed back and compared with the temperature error voltage V.sub.TE to produce a voltage level signal V.sub.L in the input of the voltage control loop, representative of the correction required to obtain and then to maintain the cryocooler temperature represented by the reference temperature voltage. Either a pulse width modulated, variable amplitude sine wave signal or a constant duty cycle, pulse width modulated, square wave signal powers the linear motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.