Control method for a variable displacement air conditioning system compressor

摘要

A control method for a variable capacity automotive air conditioning compressor in which the compressor operating point is tailored to the nonlinear control characteristics of variable displacement compressors. When the error between the desired and actual values of a specified system parameter is relatively large, the operating point is determined by a coarse gain closed-loop control. When the error is within a fine control range defined in relation to the desired value, the control point is set to one of three predetermined values for effecting small displacement increases, small displacement decreases, or no change in displacement. An adaptive tuning technique is used to update the predetermined control point values to compensate for compressor-to-compressor differences and changes in the operating conditions of a given compressor system. An anticipation technique shortens the transition from coarse control to fine control by minimizing gross overshoots of the specified system parameter.