| 摘要 |
PROBLEM TO BE SOLVED: To eliminate fear that a valve is totally closed at the time of a small flow rate control of the refrigerant by providing a control means which controls the variation amount of the valve travel at a specified value or lower when the valve travel is at a specified opening degree or less. SOLUTION: A variation amountΔPLS1 of a super heat control is calculated, and a variationΔPLS2 to prevent a frequency change and/or an over-contracted state of a compressor from generating is calculated by an interrupt processing, and these are added to calculate a variation amountΔPLS of a valve travel (201-203). Then, when the present value travel is smaller than a limited travel which is set at a position being considerably larger than an initial travel, the size of the variation amountΔPLS is limited. That is, when the variation amountΔPLS is larger than a limit valueΔPLSMAX which is determined on the opening side of the valve, the variation amount is limited asΔPLS=ΔPLSMAX, and when it is smaller than a limit valueΔPLSMIN which is determined on the closing side of the valve, the variation amount is limited asΔPLS=ΔPLSMIN (205). Then, the one to which the variation amountΔPLS of the present travel is added is made a target opening degree, and a pulse output processing is executed (206, 207).
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