Control system for refrigerant metering solenoid valve

摘要

A system including a control circuit and a sensing circuit controls an expansion valve in a refrigeration system using pulse width modulation. The control circuit includes a ramp generator, a pulse width modulator, and a power switch. In response to input from the sensing circuit, the control circuit produces a control signal which cyclically opens and closes the valve. The average flow rate through the valve is varied in accordance with a condition of the refrigeration system which is detected by the sensing circuit.