Lg Electronics Inc.

Min Ho So

Won Hee Lee

Yoon Jei Hwang

Cheol Min Kim

Deok Huh

Chang Min Choi

Disclosed are an air conditioning system with two compressors and a method for operating the same, so as to variably change a compression capacity of a refrigerant according to the variation of cooling load. Herein, when a full operation order is inputted to the two compressors in order to satisfy increased cooling load, the first compressor is first operated, and then the second compressor having a compression capacity of a refrigerant smaller than that of the first compressor is additionally operated, so that a current peak value for operating the compressors does not exceed an allowable current range of a circuit breaker installed in a home or building, thereby safely controlling the air conditioning system and simultaneously allowing the current to be provided to other electric appliances, thus improving users' convenience.

Air conditioning system with two compressors and method for operating the same

Disclosed are compressor-controlling device and method for an air conditioner comprising a plurality of compressors. In case several compressors selected from the plural compressors are stopped for a long period of time according to cooling or heating load, the refrigerant contained in a higher-pressure state inside of the stopped compressors moves toward a refrigerant pipe of a lower-pressure inlet port, and oil used to operate the compressors leaks toward the inlet port, thus lowering the oil level within the stopped compressors. Since the stopped compressors are operated during a second designated time when stopped time of the stopped compressors exceeds a first designated time, the stopped compressors are protected from damage due to poor lubrication.

Compressor-controlling device and method for air conditioner comprising a plurality of compressors

Disclosed are an apparatus for preventing an overload of an air conditioner and a method thereof. The apparatus includes current feedback units for feeding back the currents supplied to the compressors to the controller where at least one of a plurality of compressors, operated in response to currents generated from a controller for controlling an operation of the air conditioner, is in an overload state; and a comparator for sensing current differences between the currents inputted into the compressors and the currents fed back from the current feedback units. After sensing the current differences between the currents inputted into the compressors and the currents fed back from the current feedback units, the comparator determines that at least one of the compressors is in the overload state if a current difference does not exist. The controller simultaneously stops operations of the compressors, and re-operates the compressors if the overload state is relieved, thereby preventing a continuous overload state of a compressor and hence damage of a compressor.

Apparatus for preventing overload of air conditioner and method thereof

Disclosed are a defrosting apparatus of an air conditioner and a method thereof. The defrosting apparatus includes a temperature sensor for sensing a pipe temperature of an outdoor heat exchanger and an outdoor temperature; a comparator for comparing the sensed pipe temperature of the outdoor heat exchanger and the sensed outdoor temperature, and generating and outputting a comparison signal; and a valve controller for increasing an opening value of an LEV (Linear Expansion Valve) at a defrosting operation and decreasing the opening value of the LEV at a defrosting operation termination. The apparatus and the method can increase efficiency of the defrosting operation and reduce a period of time required for performing the defrosting operation by determining the defrosting operation based on a difference between a pipe temperature of an outdoor heat exchanger and an outdoor temperature and increasing an opening value of an LEV at the defrosting operation.

Defrosting apparatus of air conditioner and method thereof

Disclosed is a method for controlling the aperture ratio of a linear expansion valve (LEV) so as to control the flow rate of refrigerant circulating in an air conditioning system. The LEV aperture ratio is controlled to range from the minimum value to the maximum value, which are determined according to the compressor's capacity and the cooling and heating modes. The LEV aperture ratio is controlled also based on the compressor's operating status, the change of the indoor fan's air volume, and whether or not the indoor fan operates. Such LEV control enables refrigerant to always be circulated at a suitable flow rate, improving the cooling and heating efficiencies, and also prevents liquid refrigerant from flowing into the compressor, securing high reliability of the compressor.

Method for controlling linear expansion valve of heat-pump type air conditioning system using multi-compressors

Disclosed are compressor-controlling device and method for an air conditioner comprising a plurality of compressors. The compressor-controlling device comprises a movable timer for sensing a stopping time (t) of stopped compressors selected from the plural compressors according to a decrease of a cooling load, a comparison unit for determining whether the stopping time (t) sensed by the movable timer exceeds a designated time (T), and a control unit for re-operating the stopped compressors after a lapse of the designated time (T) when the cooling load is increased, in case the comparison unit judges that the stopping time (t) does not exceed the designated time (T). When the cooling load is increased, the stopped compressors for satisfying the decrease of a cooling load are re-operated after the lapse of the designated time. Therefore, the compressor-controlling device assures the reliability of its system.

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Seoul-si, South Korea

Min Ho So