Design and Performance Characteristics of a Drive System for a Reciprocating Compressor of a Dynamic Cooler to Be Used in Space

摘要

The drive system of a one cylinder reciprocating compressor used in a dynamic cooling system based on a vapor compression cycle is described. The drive system consists of a brushless dc motor with its separate control module, and of a speed reduction gear with a planetary gear train. The torque varies between positive and negative values during each crankshaft revolution with absolute amounts up to four times the mean value. To keep the degree of nonuniformity of rotation within reasonable limits, a motor speed eight times that of the compressor was selected. The motor control is of the two-quadrant type whereby the motor functions as such when it has to provide a positive torque, and functions as a generator when it has to decelerate the rotating parts. To avoid oil lubrication problems under zero-g conditions, the speed reduction gear uses dry lubrication in the gear train.