Refrigeration compressor driven by a DC motor

摘要

A variable capacity refrigeration system includes a control scheme having three interrelated closed loops. The system includes a refrigeration system controller and at least one variable speed, electronically commutated DC motor driving a compressor. In the first closed loop, the controller supplies a speed command signal to a motor drive which governs the speed of the motor driven compressor. The speed of the compressor varies the system's capacity to condition the temperature of a comfort zone. A temperature sensor in the zone provides a temperature feedback signal to the controller to complete the first closed loop. In the second closed loop, the speed command signal from the controller is varied in response to a speed feedback signal received from a compressor drive which includes both the motor and the motor drive. The third closed loop is between the motor drive and the motor. The motor drive electronically commutates the motor as it delivers an electrical supply to the motor in response to a position feedback signal generated from within the motor. The three loops are interrelated in that the output of the controller responds to feedback from both the temperature sensor and the compressor drive, and the output of the motor drive responds to input from both the motor and the controller.