Patent ID: 8707717
Filing Date: 2014-04-29
Classification: F25B

Abstract:
1. A method for operating a cooling device for cooling a superconductor, the cooling device including a linear compressor for compressing a working medium and a cooling unit for discharging a cooling power to a cryogenic coolant of the superconductor by expanding the working medium, the linear compressor including at least two pistons, of which at least one of the pistons movable at a frequency and a stroke in a linear manner relative to a respective other one of the pistons, the stroke of the at least one movable piston being regulateable at a target value, the method comprising: driving each of the at least one movable piston using a respective motor via a respective frequency converter for supplying the motor with electrical current at a voltage and frequency, the voltage applied to the respective motor being used as a manipulated variable for regulating a stroke of the at least one piston, the motors being configured as two-phase AC motors and the frequency converters being configured as three-phase converters with a voltage intermediate circuit, the frequency converters being connected on an input side to a three-phase network and on an output side via two phases to the respective motor, and an additional capacitor being arranged in parallel with the voltage intermediate circuits.