Abstract: In a normal control of a vehicle air conditioner, a control unit controls a compressor so that a work amount of the compressor is maintained at a target work amount calculated based on a heat load. In a cut control, the control unit controls the compressor so that the work amount is forcibly reduced smaller than the target work amount. When the cut control is set from the normal control, the cut control is continued for a predetermined time and then is changed to the normal control again. In this case, the work amount of the compressor immediately after the predetermined time passes is corrected to be increased. Thus, the target work amount of the compressor immediately after the cut control is increased larger than the target work amount calculated based on the heat load. Therefore, suitable air conditioning can be performed immediately after the cut control.

Abstract: An apparatus for driving a compressor comprises a compressor having a compression mechanism part for sucking a fluid to compress the same, and an electric motor for driving the compression mechanism part, and an inverter device for driving the electric motor at variable speeds. The electric motor comprises a self-starting type electric motor having a rotor, which comprises a cage conductor and a polarized permanent magnet, and the inverter device comprises a plurality of semiconductor switches for controlling drive frequencies of the electric motor.

Abstract: A cooled air temperature detecting means 31 for detecting the temperature of air (a post-evaporator temperature Te) that has just passed through a cooling unit 5 (a refrigerant evaporator) is constituted by a plurality of temperature thermistors for detecting air temperatures for respective areas in the event that the cooling unit 5 is divided into a plurality of areas. When determining a control condition (ON/OFF condition) of the refrigerant compressor based on the post-evaporator temperature Te, an air conditioner ECU 2 calculates and compares respective air temperatures detected by the plurality of temperature thermistors and processes a lowest air temperature as the post-evaporator temperature Te.

Abstract: A control system is provided for generating discrete stepped output capacities in a refrigeration system. The refrigeration system is preferably a multi-evaporator system having two or more multi-capacity compressors. The multi-capacity compressors can be any kind of reciprocating compressor or scroll compressor that can provide two or more different output capacities. The contributions of the compressors to the overall system capacity can be equal, or more preferably, they can be unequal, i.e., one compressor provides more capacity than the other compressor(s). The control system generates the stepped capacities of the refrigeration system by configuring and controlling the operation of the compressors and the output capacity provided by the compressors.

Abstract: A temperature control apparatus for a pulse width modulation (PWM) device. The temperature control apparatus includes a temperature detector installed around the PWM device for detecting a present working temperature of the PWM device, and a temperature comparator coupled to the temperature detector and the PWM device for comparing the present working temperature with a maximum limiting temperature and a minimum limiting temperature. When the present working temperature is higher than the maximum limiting temperature, a working frequency of the PWM device will be reduced in a step variation frequency, and when the present working temperature is lower than the minimum limiting temperature, the working frequency of the PWM device will be increased in the step variation frequency.

Abstract: A freezing prevention system for a refrigeration device includes a freezing-prevention temperature sensor for detecting a refrigerant temperature in a refrigerant evaporator, and a control unit for controlling operation of a refrigerant compressor based on the detected refrigerant temperature. The control unit includes a calculating means for calculating an integral value of the detected refrigerant temperature integrating with respect to a passed time after the detected refrigerant temperature becomes equal to or lower than 0° C. When the integral value becomes equal to or larger than a predetermined value, the control unit stops the operation of the refrigerant compressor. Accordingly, the freezing prevention system can accurately perform a freezing prevention control while its production cost can be reduced.

Abstract: When a compressor apparatus is operated at a maximum displacement for 60 minutes or longer, an ECU controls a pressure control valve to gradually change the refrigerant pressure in a swash plate chamber in a manner that gradually reduces the displacement of the compressor apparatus. In this way, it is possible to create a state, in which a relatively large pressure difference is created between a refrigerant inlet side and the swash plate chamber. Thus, refrigerant oil accumulated in the swash plate chamber can be returned to the refrigerant inlet side of the compressor apparatus at the time of gradually reducing the displacement of the compressor apparatus.

Abstract: Disclosed are an infrared sensor assembly and a refrigerator having the infrared sensor, in which a location where a heat source is generated is precisely detected by narrowing a receiving angle of an infrared sensor. To this end, the infrared sensor assembly comprises: an infrared sensor fixed to a supporting frame for receiving infrared rays generated at a heat source; a case having the infrared sensor mounted therein and an infrared filter mounted at an upper surface thereof, the infrared filter transmits only the infrared rays; and a receiving range limiting means prolonged from an outer circumference surface of the case with a predetermined height for limiting a range of the infrared rays received into the infrared sensor so as to precisely detect a location of the heat source.

Abstract: An air conditioner and a method of controlling the air conditioner includes a variable capacity compressor being operated at a maximum capacity in a case of starting an operation of the compressor after an extended stoppage for a lengthy period of time longer than a preset reference time, thus increasing a flow rate of a circulated refrigerant during an initial stage of the operation and increasing a quantity of heat generated from the motor of the compressor to vaporize and forcibly discharge a remaining liquid refrigerant from the compressor during the initial stage. Therefore, the variable capacity compressor of the air conditioner does not require heaters conventionally used for heating the refrigerant during such a stoppage, and so easy designing and production of the compressor is achieved, in addition to a reduction in a production cost of the air conditioner. This air conditioner also accomplishes a reduction in a maintenance cost thereof.

Abstract: Disclosed herein is an air conditioner and method of controlling the same. The air conditioner includes a compressor having a capacity variable according to a duty control signal. The duty control signal controls the compressor to undergo a loading time for maintaining a loading state in a cycle and an unloading time for maintaining an unloading state in a cycle. The air conditioner further includes a control unit for determining the loading time and the unloading time according to the variation of a total required cooling capacity to generate the duty control signal even before a corresponding cycle is over, if the total required cooling capacity has been varied in a corresponding cycle while the compressor is operated, and controlling the compressor according to the duty control signal.

Abstract: An air conditioner includes a direct-current (DC) power supply, a compressor, and a compressor driving device that converts a current supplied from the DC power supply into an alternate-current (AC) for driving the compressor. The DC power supply energizes the driving device through a center conductor and an outer conductor of a shield cable. This structure allows the driving device not to include a capacitor for smoothing a power current, and to suppress surge voltages and electromagnetic-wave radiation, thus providing an air-conditioner including a compact size and light-weighted compressor driving device.

Abstract: To provide a transportable cooling unit for maintaining a transport volume at a defined temperature, comprising a closed cooling circuit and a controller sensing a temperature present within said transport volume and controlling said cooling circuit so as to provide the cooling power demanded at said evaporator for maintaining said defined temperature and minimizing energy consumption, said controller operates said closed cooling circuit between a maximum possible heating power and a maximum possible cooling power in a sequence of different operational stages, said controller further operates said closed cooling circuit in each one of at least two upper operational cooling stages at a compressor speed related cooling capacity different from said compressor speed related cooling capacity in said other upper operational stages and within said respective upper operational stages said controller operates a compressor in an uninterrupted mode and adjusts said cooling power stepless speed control of said compressor

Abstract: In a cooling system for cooling racks in a data center, cooling fluid is circulated in the data center by a cooling device having a fan. In addition, this system includes a plenum having a plurality of returns and an outlet. The outlet of the plenum is in fluid communication with the fan and the plurality of returns are configured for removing the cooling fluid from the data center. Furthermore, the returns and are operable to vary a characteristic of the removal of the cooling fluid.

Abstract: In a cooling system for cooling racks in a data center, cooling fluid is circulated in the data center by a cooling device having a fan. In addition, this system includes a plenum having a plurality of returns and an outlet. The outlet of the plenum is in fluid communication with the fan and the plurality of returns are configured for removing the cooling fluid from the data center. Furthermore, the returns and are operable to vary a characteristic of the removal of the cooling fluid.

Abstract: In a cooling system for cooling racks in a data center, cooling fluid is circulated in the data center by a cooling device having a fan. In addition, this system includes a plenum having a plurality of returns and an outlet. The outlet of the plenum is in fluid communication with the fan and the plurality of returns are configured for removing the cooling fluid from the data center. Furthermore, the returns and are operable to vary a characteristic of the removal of the cooling fluid.

Abstract: Disclosed is an apparatus and a method for controlling a driving of a reciprocating compressor for a refrigerator using a linear motor, in which a capacitance is varied according to a variation of a driving load, thereby improving a driving efficiency of the compressor. To this end, the apparatus for controlling a driving of a reciprocating compressor for a refrigerator using a linear motor comprises a first capacitor for attenuating an inductance of a coil wound on a motor; a second capacitor connected to the first capacitor in parallel; and a relay connected to the second capacitor in series to be turned on/off; and a microcomputer for outputting a control signal to turn on/off the relay according to the driving load of the refrigerator.

Abstract: The invention proposes an air conditioning system for motor vehicles which is fitted with an injection computer and an electronic control device. The system comprises a first measuring member suitable for supplying a value relating to the pressure of the fluid at a first point in the air conditioning circuit which is situated between the outlet of the expansion member and the outlet of the evaporator, and a second measuring member suitable for supplying a value relating to the pressure of the fluid at a second point in the air conditioning circuit which is situated at the inlet to the compressor. The electronic control device makes use of the solution of an equation which relates the mass flow rate of the refrigerant fluid to the difference in pressure between the first point and the second point in order to calculate an estimate of a magnitude relating to the refrigerant fluid.

Abstract: An air conditioning system for a vehicle that is driven by a vehicular power source. The system has a compressor selectively operable by the vehicular power source and an electric motor. The electric motor is used as a drive force of the compressor when the vehicular power source is in a non-operative state. The compressor compresses refrigerant gas introduced into a suction chamber from an external refrigerant circuit. A displacement of the compressor is variable, based on a differential pressure. The compressor has a control valve that is disposed on a refrigerant passage communicating with the crank chamber. The control valve has a valve plunger for changing an opening size of the control valve to adjust pressure in the crank chamber. The air conditioning system comprises pressure sensing member, actuator, and controller. The pressure sensing member is disposed in the control valve and applies biasing force to the plunger based on pressure in the external circuit.

Abstract: A hybrid compressor system in a vehicle air conditioner includes a variable displacement hybrid compressor, a detector for detecting information for air conditioning, a thermal load calculator and a controller. The compressor is selectively driven by an engine and an electric motor. The calculator calculates a thermal load based on the detected information. The controller compares the thermal load with a predetermined value. The controller changes displacement of the compressor to a first predetermined displacement value and selects the engine as a drive source of the compressor when the thermal load is larger than the predetermined value. The controller changes the displacement of the compressor to a second predetermined displacement value that is smaller than the first predetermined displacement value and selects the electric motor as the drive source of the compressor when the thermal load is equal to, or smaller than the predetermined value.

Abstract: An air-conditioning system with a refrigerant medium circulating in a refrigerant loop has a variable-stroke compressor with a high-pressure outlet chamber, a drive chamber and an intake suction chamber. A first valve regulates a first flow of refrigerant medium from the high-pressure outlet chamber to the drive chamber, and a second valve regulates a second flow of refrigerant medium from the drive chamber to the intake suction chamber. The first and second valves operate independently of each other under the control of a control unit, and the variable stroke of the compressor is controlled by the first and/or second flow of refrigerant medium.

Abstract: Disclosed are an infrared sensor assembly and a refrigerator having the infrared sensor, in which a location where a heat source is generated is precisely detected by narrowing a receiving angle of an infrared sensor. To this end, the infrared sensor assembly comprises: an infrared sensor fixed to a supporting frame for receiving infrared rays generated at a heat source; a case having the infrared sensor mounted therein and an infrared filter mounted at an upper surface thereof, the infrared filter transmits only the infrared rays; and a receiving range limiting means prolonged from an outer circumference surface of the case with a predetermined height for limiting a range of the infrared rays received into the infrared sensor so as to precisely detect a location of the heat source.

Abstract: A control system is provided to maintain stable operating conditions for centrifugal compressors operating in parallel when one of the centrifugal compressors enters into an unstable operating condition. The control system determines an unstable operating condition in response to signals indicating the motor current or power consumption of each compressor and the position of the pre-rotation vanes of the compressors. Once an unstable operating condition is determined, the control system closes the pre-rotation vanes to each compressor until the unstable operating condition has been corrected.

Abstract: A refrigeration system including an evaporator, a suction header in fluid communication with the evaporator, a compressor in fluid communication with the suction header, and a condenser in fluid communication with the compressor and the evaporator. The refrigeration system further including a controller operable to control the compressor and a sensor coupled to the compressor. The sensor is operable to acquire a parameter for the compressor. The method of operating the refrigeration system includes acquiring a value for the parameter with the sensor, and determining if the sensor is faulty.

Abstract: A refrigeration system comprises a condenser, an evaporator, and a plurality of compressors in fluid communication. The plurality of compressors has a current run pattern with a current run capacity. The refrigeration system further comprises a controller operable to control the plurality of compressors. One method of operating the refrigeration system includes, at the controller, determining whether to increase or decrease the current run capacity and, when an increase or decrease in the current run capacity is required, creating a new run pattern to replace the current run pattern.

Abstract: Disclosed are a heat pump air conditioning system comprising an additional heater and a method for operating the same, in which the additional heater is driven during a full activation standby time taken to simultaneously operate all of a plurality of compressors so as to rapidly satisfy an increased heating load. When the increased heating load exceeding a total capacity of some compressors selected from the plural compressors is sensed, since the additional heater is driven during the full activation standby time so as to rapidly satisfy the increased heating load, the air conditioning system improves heating effectiveness and uniformly maintains room temperature, thereby improving users' comfort.

Abstract: A vehicle air conditioning apparatus includes a heater core 21 radiating heat of engine coolant to an air stream to be blown off to a vehicle compartment, a sub condenser 4 operative to radiate heat of compressed refrigerant to the air stream to be blown off to the vehicle compartment for condensing refrigerant, an evaporator 7 operative to allow expanded refrigerant by an expansion valve 6 to absorb heat of the air stream in the vehicle compartment to be evaporated, a variable displacement compressor 2 operative to compress evaporated refrigerant to be discharged to the condenser 4, a sensor 9 that detects a discharge refrigerant pressure of the compressor 2, and a compressor control means 100 operative to control a discharge refrigerant volume of the compressor 2 so as to compel a blow-off temperature to lie at a given temperature in response to a detected result of the sensor 9.

Abstract: A centrifugal chiller includes both a unit-mounted full-voltage starter and a unit-mounted reduced-voltage starter. The chiller is rather large with a rated cooling capacity of at least 300 tons and is driven by a motor that is powered by at least 2,000 volts. The chiller includes an evaporator shell and a condenser shell in a staggered arrangement to provide a combined height of between 6 and 12 feet and a combined width of between 5 and 8.5 feet. The staggered arrangement of the shells plus mounting the two starters at opposite sides of the motor provide a chiller whose outer dimensions permit the chiller to be shipped as a single package without exceeding certain shipping limits.

Abstract: An improved cryogenic compressor with piston position sensing is disclosed. Precision optical encoders using incremental or absolute encoding are incorporated into a compressor to allow for accurate position sensing of moving elements within the compressor. Appropriate electronic circuitry is used to interpret the position data to allow the user modify the frequency and stroke of the piston within the compressor. The invention may be used in systems with multiple compressor pistons or for position data for balance weights or displacers in a cryogenic refrigeration system.

Abstract: In a motor vehicle with a combustion engine, an electronic engine-management device, and an air-conditioning system with an air-conditioning control device, the air-conditioning compressor has reciprocating pistons whose displacement stroke is adjustable through one or more control valves. The electronic engine-management device has direct access to and priority control over the adjustment of the piston stroke, so that the electronic engine management device takes precedence over the air-conditioning control device in controlling the adjustment of the piston stroke.

Abstract: An air conditioning system for a vehicle includes a controller for periodically increasing the stroke and output of the pistons in a variable stroke compressor for periodically reducing the amount of refrigerant resident in the evaporator. The controller includes a timer for establishing predetermined time periods between the momentary spikes of periodic increases of stroke. Normally, the stroke is spiked only when the compressor is operating at a low load condition.

Abstract: A vehicle air-conditioning system calculates and indicates the remaining time of effective cooling by cold air discharge from its cold storage unit during a vehicular eco-run halt. In cold discharge cooling mode, a first cold discharge cooling remaining time tx1 is calculated from the remaining cold heat of a cold storage medium. A second cold discharge cooling remaining time tx2 is calculated from temperature changes of the cold storage unit. The second remaining time tx2 is set to zero when the cold storage unit temperature rises to a cooling upper target temperature. The first remaining time tx1 is selected in the cold discharge cooling mode as long as the temperature of the cold storage unit is below a temperature near the solidifying point of the cold storage medium. The second remaining time tx2 is selected when the cold storage unit temperature exceeds the temperature near the solidifying point.

Abstract: An air-conditioning system for a vehicle, including a refrigerant circuit and an engine, has a battery, a compressor, an electric motor and a load torque control mechanism. The battery supplies electric power. The compressor is operative to compress refrigerant gas for the air-conditioning system. The electric motor is electrically connected to the battery. The motor is driven due to the electric power, and is operatively coupled to drive the compressor when the motor is energized. The load torque control mechanism responsive to the operating condition of the engine to control the load torque of the compressor below a predetermined value during times when the motor is driving the compressor.

Abstract: A compressor device for a refrigerant cycle includes a compressor and a control unit. The compressor is provided with a displacement changing mechanism for changing its displacement. The control unit changes a current value supplied to the displacement changing mechanism, thereby relatively changing the displacement of the compressor. In the compressor device, when a rotational speed of a vehicle engine is lower than a predetermined rotational speed, the control unit controls an upper limit of the current value between a first predetermined value and a maximum value. Accordingly, a displacement specification of the compressor device can be normalized for vehicle engines having different power outputs, while engine stall can be prevented.

Abstract: In an air conditioner having a control unit receiving a power from a switching power supply, a supplied voltage for the control unit is reduced to a possible lowest voltage for the unit to operate. This arrangement provides the air conditioner with less electromagnetic wave noise of the switching power supply, with a quick check and repair, and with having a motor-driven compressor quick start.

Abstract: A refrigeration cycle apparatus having a linear compressor is provided with a volume circulation rate instruction unit for obtaining a volume circulation rate Vco of a refrigerant in accordance with refrigerating capacity required of the refrigeration cycle apparatus, on the basis of an ambient temperature of an indoor heat exchanger (evaporator), a target temperature set on the evaporator by the user, and an ambient temperature of an outdoor heat exchanger (condenser); a volume circulation rate detector for detecting a volume circulation rate Vcd of the refrigerant that actually circulates in a refrigerant circulation path of the refrigeration cycle apparatus; and an inverter for generating an AC current for driving the linear compressor; wherein the inverter is controlled so as to decrease a difference between the volume circulation rate Vco and the volume circulation rate Vcd.

Abstract: Disclosed is an apparatus and a method for controlling a driving of a reciprocating compressor for a refrigerator using a linear motor, in which a capacitance is varied according to a variation of a driving load, thereby improving a driving efficiency of the compressor. To this end, the apparatus for controlling a driving of a reciprocating compressor for a refrigerator using a linear motor comprises a first capacitor for attenuating an inductance of a coil wound on a motor; a second capacitor connected to the first capacitor in parallel; and a relay connected to the second capacitor in series to be turned on/off; and a microcomputer for outputting a control signal to turn on/off the relay according to the driving load of the refrigerator.

Abstract: An air conditioner and a method of controlling the air conditioner includes a variable capacity compressor being operated at a maximum capacity in a case of starting an operation of the compressor after an extended stoppage for a lengthy period of time longer than a preset reference time, thus increasing a flow rate of a circulated refrigerant during an initial stage of the operation and increasing a quantity of heat generated from the motor of the compressor to vaporize and forcibly discharge a remaining liquid refrigerant from the compressor during the initial stage. Therefore, the variable capacity compressor of the air conditioner does not require heaters conventionally used for heating the refrigerant during such a stoppage, and so easy designing and production of the compressor is achieved, in addition to a reduction in a production cost of the air conditioner. This air conditioner also accomplishes a reduction in a maintenance cost thereof.

Abstract: A refrigerating apparatus comprises: a first substrate, on one surface of which an active converter and an inverter are mounted, and on a reverse surface of which a radiation fin is closely fixed; a second substrate, on which a microcomputer, a current detecting mechanism, and a terminal block are mounted; a resin casing covering sides of the first and second substrates and provided with a step permitting the terminal block to be arranged thereon; and a third substrate, on which an interface connector and a photo-coupler are mounted. The first substrate, the second substrate, and the third substrate are layered in this order on a bottom surface of the casing. Gel is filled up to a power semiconductor surface of the first substrate, and a resin is filled up to an upper surface of the second substrate.

Abstract: A clutch of the compressor is selectively engaged and disengaged by a coaction of an engine ECU and an air-conditioning ECU. If an air-conditioning system operating switch is detected as being turned on after a startup of an engine is detected, the clutch is changed from an off-state to an on-state to actuate the compressor to discharge a liquid refrigerant therefrom on the condition that an engine coolant temperature is higher than a reference engine coolant temperature. When the engine coolant temperature is higher than the reference engine coolant temperature, e.g., 40° C., the liquid refrigerant stored in the compressor is discharged of its own accord, and hence the amount of the liquid refrigerant stored in the compressor becomes small.

Abstract: An air conditioner for a vehicle uses a hybrid compressor (4) including a first compression mechanism driven by a first drive source (2) and a second compression mechanism driven by a second drive source (5), and a single discharge port connected to the first and the second compression mechanisms. The operation of the hybrid compressor is controlled by a controller (15) in accordance with a control mode. The controller has a first operation mode in which the first compression mechanism alone is driven, a second operation mode in which the second compression mechanism alone is driven, a third operation mode in which the first and the second compression mechanisms are simultaneously driven, and a fourth operation mode in which the first and the second compression mechanisms are simultaneously stopped. Depending upon various conditions, the controller selects, as the control mode, one of the first, the second, the third, and the fourth operation modes.

Abstract: A method for controlling operation of a centrifugal cooling apparatus, which has at least one of an evaporator, a centrifugal compressor having a magnetic bearing system, a condenser, and an expansion device, includes monitoring an operating condition of the magnetic bearing system, and controlling compressor flow stability based upon the operating condition of the magnetic bearing system.

Abstract: An air conditioner control system comprises an outdoor unit having a compressor controlled by pulse-width modulation, and a plurality of indoor units. Each of the plurality indoor units has an indoor control unit to calculate a respective required individual cooling capacity, and an indoor communication circuit unit through which the required individual cooling capacity calculated is transmitted. The outdoor unit has an outdoor control unit producing a duty cycle control signal in response to the required individual cooling capacity transmitted from the indoor units to control the capacity of the compressor, and an outdoor communication circuit unit to communicate the indoor communication circuit unit of respective ones of the plurality of indoor units.

Abstract: An air conditioner for air conditioning the interior of a compartment includes a compressor and an electric motor. The compressor compresses refrigerant gas and changes the displacement. The electric motor drives the compressor. A motor controller rotates the motor at a constant reference speed. A detection device detects information related to the thermal load on the air conditioner. A current sensor detects the value of current supplied to the electric motor. A controller controls the compressor based on the detected thermal load information and the detected current value. The controller computes a target torque of the compressor based on the thermal load information. In accordance with the computed target torque, the controller computes a target current value to be supplied to the electric motor. The controller further controls the displacement of the compressor such that the detected current value matches the target current value.

Abstract: An air conditioning system for a vehicle that is driven by a vehicular power source. The system has a compressor selectively operable by the vehicular power source and an electric motor. The electric motor is used as a drive force of the compressor when the vehicular power source is in a non-operative state. The compressor compresses refrigerant gas introduced into a suction chamber from an external refrigerant circuit. A displacement of the compressor is variable, based on a differential pressure. The compressor has a control valve that is disposed on a refrigerant passage communicating with the crank chamber. The control valve has a valve plunger for changing an opening size of the control valve to adjust pressure in the crank chamber. The air conditioning system comprises pressure sensing member, actuator, and controller. The pressure sensing member is disposed in the control valve and applies biasing force to the plunger based on pressure in the external circuit.

Abstract: A brine cooling apparatus is provided which addresses an environmental problem by not contributing to global warming and can prevent brine from freezing within a heat exchanger. The apparatus is structured such that a screw compressor, a condenser, a main expansion valve and an evaporator are connected by a pipe so as to cool brine flowing through the evaporator. The refrigerant is an ammonia refrigerant, the evaporator is a plate type heat exchanger constructed by laying a plural sheets of plates, and capacity control means is provided in such a manner as to control a capacity of the screw compressor in accordance with the flow amount of the brine.

Abstract: A motor drive-control device drive-controls a plurality of auxiliary devices with a single motor while securing a necessary capacity of the auxiliary devices side in correspondence with usage conditions. As such, in an air-conditioning system, necessary speeds of auxiliary devices such as a compressor and a warm water pump are calculated based on a necessary cooling capacity and a necessary heating capacity. The higher of these two necessary speeds is set as the motor speed for driving the auxiliary devices. The motor is thus controlled to this speed. Therefore, even if the air-conditioning heat load varies greatly due to changes in the usage environment, cooling and heating capacities necessary for air-conditioning temperature control can be obtained at all times.

Abstract: A method for controlling operation of a centrifugal cooling apparatus, which has at least one of an evaporator, a centrifugal compressor having a magnetic bearing system, a condenser, and an expansion device, includes monitoring an operating condition of the magnetic bearing system, and controlling compressor flow stability based upon the operating condition of the magnetic bearing system.

Abstract: A separate-type air conditioner that can reduce the effect of voltage fluctuations in a commercial power supply (12) on a compressor (11), reduce material costs while maintaining vibrations of an outdoor unit (2) at low levels, and improve working efficiency during an assembly operation. The outdoor unit (2) includes a voltage correction circuit (14) to keep an output voltage to the compressor (11) constant (optimum) irrespective of the voltage fluctuations in the commercial power supply (12).

Abstract: A cooling system controller controls the capacity of a variable capacity compressor based upon the temperature of a housing being cooled, the suction pressure of the compressor or both of these criteria. The cooling system controller is capable of controlling either single-evaporator or multiple-evaporator refrigeration systems. The multiple-evaporator systems can have evaporators of similar temperatures or of mixed temperatures. The controller also allows the use of one or more condenser fans that are operated in a lead/lag fashion to control the cooling capability of the system.

Abstract: Air conditioning systems (1) may include an air conditioning circuit (2) and an electrically driven compressor (C). The compressor may have a motor (M) that includes a rotor (12) and a stator (14). The rotor may be rotated by a magnetic force generated when current is supplied to the stator. A temperature sensor (22) may detect the temperature of the rotor or the ambient temperature when the rotor is started to be rotated. A current calculator (26) may calculate a demagnetization limit current of the rotor at the detected temperature. The calculated demagnetization limit current may be used for determining a current that will be supplied to the stator for a predetermined period. In the alternative, the supplied current may increase as the rotor temperature increases during the initial operation. Preferably, the current may be less than the demagnetization limit current and may be greater than a minimum current that is required to rotate the rotor.