| 摘要 |
PURPOSE:To quickly dissolve the state of excess of the inverter current by a method wherein, when the inverter current has reached the upper limit, the inverter frequency is decreased in steps at specified intervals of time until the inverter current declines below the upper limit and, on the other hand, a switch-valve connected between the top of a receiver and the downstream line at an expansion mechanism is kept open for a specified period of time. CONSTITUTION:A refrigerant line 9 is formed with the interposition of a compressor 1 whose operating frequency is varied under the control by an inverter, a condenser 3, a receiver 4, an expansion mechanism 5, and an evaporator 6 in sequence; the top of the receiver 4 and the downstream line at the expansion mechanism 5 are connected by interposing a switch-valve SV. When the inverter current has assumed a state of excess and has reached a drooping level, a drooping-controlling means 51 controls the inverter frequency in a manner of decreasing it in steps at specified intervals of time until the state of excess of the inverter current is dispelled and, on the other hand, the switch-valve SV is kept open for a specified period of time. By this method a decrease in amount of the refrigerant in circulation and a decrease in the differential pressure between the high pressure and the low pressure can both be achieved and the inverter current is decreased below the drooping level quickly. |
