Compressor pulse width modulation

Abstract

A scroll compressor includes a capacity modulation system. The capacity modulation system has a piston that is connected to the non-orbiting scroll that disengages the non-orbiting scroll from the orbiting scroll when a pressure chamber is placed in communication with the suction chamber of the compressor. The non-orbiting scroll member moves into engagement with the orbiting scroll when the chamber is placed in communication with the discharge chamber. The engagement between the two scrolls is broken when the pressure chamber is placed in communication with fluid from the suction chamber. A solenoid valve controls the communication between the pressure chamber and the suction chamber. By operating the valve in a pulsed width modulated mode, the capacity of the compressor can be infinitely varied between zero and one hundred percent.

Description

FIELD OF THE INVENTION

[0001] The present invention is related to scroll-type machinery. More particularly, the present invention is directed towards capacity modulation of scroll-type compressors.BACKGROUND AND SUMMARY OF THE INVENTION

[0002] Scroll machines are becoming more and more popular for use as compressors in refrigeration systems as well as air conditioning and heat pump applications. The popularity of scroll machinery is primarily due to their capability for extremely efficient operation. Generally, these machines incorporate a pair of intermeshed spiral wraps, one of which is caused to orbit with respect to the other so as to define one or more moving chambers which progressively decrease in size as they travel from an outer suction port towards a center discharge port. An electric motor is normally provided which operates to drive the scroll members via a suitable drive shaft. During normal operation, these scroll machines are designed to have a fixed compression ratio.[00...

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