Method for controlling the speed of series-connected cryogenic compressors for cooling cryogenic, cryogenic helium

摘要

The invention relates to a method for controlling rotational speeds of compressors arranged in series, for compressing a fluid, in particular cryogenic helium, wherein a desired inlet pressure, which the fluid is to have at an inlet of the compressor disposed furthest upstream, is an actual -Incremental pressure of the fluid is detected at that input, an actual discharge pressure of the fluid at an outlet of the most downstream compressor is detected, an actual total pressure ratio is detected, the actual total pressure ratio of the quotient of the actual discharge pressure and the Is the inlet pressure corresponding to a proportional integral value of the deviation of the actual inlet pressure of the target inlet pressure is determined, a capacity factor from the proportional integral value and the actual total pressure ratio is determined, a model total pressure ratio of the actual Total pressure ratio and the capacity factor is determined, a r educed target speed is determined for each compressor, wherein the respective reduced target speed is determined as the function value of the respective compressor associated control function, which assigns each value pair of capacity factor and model total pressure ratio, a reduced target speed, and the speed of each compressor is set based on the determined for him reduced target speed.