Abstract: A method for operating a pulse tube cryocooler system wherein in the event the mean pressure of the working gas within the fixed volume of the cryocooler undergoes a change, the operation of the system is kept from severe degradation by changing the frequency of the pressure wave generator driving the cryocooler directly with the change in the mean pressure.

Abstract: A method includes determining base-line operating parameters for a compressor, generating a high-side signal indicative of high-side compressor operating conditions, generating a low-side signal indicative of low-side compressor operating conditions, and comparing the high-side and low-side signals to the base-line operating parameters to determine a system operating condition.

Abstract: An apparatus for controlling a variable displacement compressor has an information detector and a controller. The information detector detects information about the thermal load on the refrigeration circuit. The controller determines a target value that reflects the displacement of the compressor based on the information about the thermal load detected by the information detector, and outputs the target value as a command value. When determining that the compressor is in a heavy load state based on information about a load on the compressor, the controller changes the command value to a value that causes the displacement of the compressor to become smaller than a displacement that corresponds to the determined target value.

Abstract: A compressor unit includes a compressor, an inverter for driving the compressor, and an over-current protective device for protecting the inverter against an output over-current. A control part controls the output voltage of the inverter when the compressor is started based on a ambient temperature detected by a temperature sensor so that the input current of the inverter does not exceed the working current value of the over-current protective device having temperature characteristics varying according to the ambient temperature. Thereby, a start torque can be increased by increasing the output voltage of the inverter without operating the over-current protective device when the compressor is stated at a low temperature when a start load is increased.

Abstract: A system and method are provided for variable speed operation of a screw compressor to obtain increased capacity and efficiency. The screw compressor is connected to an induction motor driven by a variable speed drive, wherein the screw compressor has a variable output capacity that is dependent on the output speed of the motor. To obtain increased capacity and efficiency, the screw compressor is operated at a speed greater than the screw compressor's rated speed and does not include a slide valve. The maximum operating speed of the screw compressor, which speed is greater than the rated speed, is related to the maximum operating speed of the motor when operated at a voltage and frequency provided by the variable speed drive that is greater than the motor's rated voltage and frequency in a constant flux or constant volts/Hz mode.

Abstract: A system and method are provided to increase the horsepower of an induction motor. One technique for increasing the horsepower of a motor is to connect the motor to a variable speed drive that is providing an output voltage and frequency greater than the standard line voltage and frequency. The connection of the variable speed drive to the induction motor enables the motor to be operated in constant flux or constant volts/Hz mode and provide a greater output horsepower. Another technique for increasing the horsepower of a motor is to use a dual voltage motor configured for lower voltage operation and then provide the motor with the corresponding voltage and frequency for higher voltage operation. The higher voltage and higher frequency can be provided by a variable speed drive with or without voltage boost. A variable speed drive without voltage boost, but with frequency boost, can be used in situations where the standard main voltage is greater than the lower voltage rating.

Abstract: Gas compression system comprising a driver; a refrigerant compressor driven by the driver and having an inlet and an outlet; a relief pressure safety valve having an inlet in flow communication with the outlet of the compressor, an outlet, and a set point; and a recycle pressure safety valve having an inlet in flow communication with the outlet of the compressor, an outlet in flow communication with the inlet of the compressor, and a set point that is lower than the set point of the relief pressure safety valve.

Abstract: A refrigerator having a compressor and a control unit for selectively activating and deactivating the compressor in response to the temperature inside the refrigerator. The selective activation and deactivation of the compressor being carried out at predetermined cut-on and cut-off temperatures. The control unit being adapted to detect how the actual temperature inside the refrigerator increases above the cut-on value due to a special event, and to adjust the cut-off temperature of the refrigerator accordingly, in order to keep the temperature of stored food substantially constant.

Abstract: A method and apparatus which provides a pressure sensor and/or temperature sensor connected to the low pressure side of a refrigeration system, or the discharge line of a scroll compressor. When the scroll compressor rotates backward, the change of pressure or temperature immediately sends a signal to work with a time-delay relay and a normally closed relay to immediately cut off the electrical power supply to the compressor. Thus, causing the scroll compressor to stop rotating in the undesirable direction.

Abstract: An object is to improve cooling efficiency while preventing an abnormal increase in pressure of a high side in a cooling apparatus which uses so-called carbon dioxide as a refrigerant. The cooling apparatus comprises a refrigerant circuit in which a compressor, a gas cooler, pressure reducing means, an evaporator and the like are connected in an annular shape, and carbon dioxide is sealed as a refrigerant. In a stable running state in which a temperature of a space to be cooled by the evaporator is cool, time after a start of the compressor until a difference between outlet and inlet temperatures of the evaporator becomes within 1 degree is 5 minutes or more to less than 20 minutes.

Abstract: An electromagnetic clutch for a compressor includes a rotor, an armature, an electromagnetic coil for bringing the rotor into contact with the armature and for separating the rotor from the armature, and a temperature detection device, such as a temperature fuse or a temperature switch, or both, for detecting an excessive increase in temperature ascribed to slippage between the rotor and the armature or a temperature increase of refrigerant discharged from the compressor. An electric circuit of the temperature detection device is separated from the electric circuit of the electromagnetic coil. An abnormal condition may be accurately detected by the separate circuit structure, and a proper response to the abnormal condition may be taken quickly.

Abstract: A secondary drive system for an air conditioner compressor includes a conventional air conditioning circuit having integrated therewith a secondary compressor drive. The secondary compressor drive includes an air motor for selectively operating the otherwise conventional compressor of the air conditioning circuit and a compressed fluid source for driving the air motor. The compressed fluid source includes a pressure vessel and a collection reservoir. Heat generated in the operation of the air conditioning circuit is utilized to convert a liquid phase of the operating fluid into a highly compressed gas within the pressure vessel whereafter the resulting compressed gas is utilized to drive the air motor. The air motor operates the compressor of the air conditioning circuit. The operating fluid is captured within the collection reservoir as a gaseous or vaporous operating fluid for reuse in the system of the present invention.

Abstract: A hybrid compressor includes a first compression mechanism, which is driven by a first drive source, and a second compression mechanism, which is driven by a second drive source. A first discharge port of the first compression mechanism and a second discharge port of the second compression mechanism are connected to a single discharge path.

Abstract: A refrigeration system including a compressor, condenser, valve, and evaporator in fluid communication; a system controller operable to control one or more aspects of the refrigeration system, and a subsystem controller in communication with the system controller. The subsystem controller is operable to control one of the compressor, condenser, valve, and evaporator. A method of operating the refrigeration system includes communicating a code from the subsystem controller to the system controller, obtaining information at the system controller having a relation to the code; and communicating at least a portion of the obtained information from the system controller to the subsystem controller.

Abstract: Disclosed herein is an air conditioning unit and method of operating the same. The air conditioning unit has a power level control unit (6) for controlling the level of power supplied to a motor (2a) of a compressor. The power level control unit (6) is comprised of a first supplying unit (6a) for supplying first level power to the compressor motor (2a), and a second supplying unit (6b) for supplying second level power to the compressor motor (2a). If an operation cycle of the compressor corresponds to a loading operation, the power level control unit (6) supplies first level power for compressing a cooling agent through the first supplying unit (6a). Further, if an operation cycle of the compressor corresponds to an unloading operation, the power level control unit (6) supplies second level power less than the first level power through the second supplying unit (6b).

Abstract: A system and method is disclosed for creating and/or maintaining an electrical load on a diesel engine generator for use on a marine vessel in order to avoid the harmful effects of no-load or low-load operation of the diesel engine. The parasitic load bank system 10 utilizes the heat transfer fluid 23 contained in the closed circulation loop 28 of a chille7d-fluid air conditioning system 14 for creating and/or maintaining the electrical load on the diesel engine generator 12 by utilizing a load bank controller 44 for diverting a portion 23c of the heat transfer fluid 23a being supplied to the vessel's air handlers 42 into heat exchange relationship with the heat transfer fluid 20b discharged from the air conditioning system's source of heat transfer 18 such that the heat exchanged heat transfer fluid 23f activates the source of heat transfer 18, which may be a chiller, reverse-cycle chiller or heat pump, to create an electrical power demand on the diesel engine generator 12.

Abstract: A fan speed control includes a power adapter, a CPU programmed with a phase splitting program, a current-limit resistor, a capacitor, a TRIAC, and a switch module, the CPU having a signal input terminal connected in series to the power input terminals of the power adapter through the current-limit resistor to obtain synchronous signal frequency as input signal, a signal output terminal connected in series to the capacitor and then the gate of the TRIAC for enabling the CPU to control triggering of the TRIAC, the TRIAC having the gate connected in series to the capacitor, and the anode and cathode respectively connected to the fan motor and the power output terminal of the power adapter, so that the fan motor, the TRIAC and the power adapter form a loop in which the TRIAC controls the operation speed of the fan motor; the switch module having one end connected to the control input terminal of the CPU for controlling the output state of the signal output terminal of the CPU and the other end connected to the po

Abstract: A refrigeration system including a compressor, condenser, valve, and refrigeration branch, all of which is in fluid communication. The refrigeration branch includes an evaporator coil. The refrigeration system further includes a case adapted to be cooled by the evaporator coil, and a system controller operable to control one or more aspects of the refrigeration system, and a subsystem controller in communication with the system controller. The subsystem controller is operable to control a subsystem having one of the compressor, condenser, valve, refrigeration branch, and case. The method of operating the refrigeration system includes at the subsystem controller, monitoring a parameter of the subsystem, comparing the monitored parameter with a parameter limit, generating an alarm when the parameter is not within the parameter limit, and communicating the alarm to the system controller.

Abstract: A refrigeration unit using ammonia aimed to reduce the amount of charged ammonia, and to establish a measure to render leaked ammonia gas harmless, is provided. The ammonia chiller unit comprises a compressor, a compressor driving motor, an evaporation type condenser, an expansion valve, an evaporator to perform refrigerating cycle using ammonia as a refrigerant. The unit is composed of a lower construction body comprising a compressor, a motor for driving the compressor, a control board, a brine cooler to function as an evaporator, a brine pump, a water tank, a sprinkler pump, etc., and an upper construction body comprising a drain pan and an evaporation type condenser located above the drain pan. The evaporation type condenser is composed of a multitubular heat exchanger having at both end sides an inlet and outlet headers, ammonia refrigerant flowing in one direction, and the multitubular heat exchanger is incline downward from the inlet side toward the evaporator.

Abstract: The present invention discloses an apparatus and method for controlling an operation of an outdoor unit which can efficiently control the outdoor unit by mounting sensors on the outdoor unit. The apparatus for controlling the operation of the outdoor unit includes: a pressure sensor for sensing a pressure of refrigerants in an outlet of a compressor of the outdoor unit; a temperature sensor for sensing a temperature of the refrigerants in an outlet of a condenser; and a microcomputer for comparing the pressure from the pressure sensor and the temperature from the temperature sensor with optimal pressure and temperature ranges, and controlling operation conditions of at least a blast fan and the compressor in the outdoor unit to be inversely proportional to each other according to the comparison results.

Abstract: A refrigerating and air-conditioning system includes a refrigerating machine connected to a showcase by a first refrigerant flow passage, an air-conditioning apparatus for connection of an indoor equipment and an outdoor equipment by means of a second refrigerant flow passage, which forms a different refrigerant circuit from a refrigerant circuit formed by the first refrigerant flow passage, and a centralized control unit for controlling the refrigerating machine and the air-conditioning apparatus, the centralized control unit configured to reduce a cooling operation set temperature in the air-conditioning apparatus relative to a fixed value according to a load on the showcase. When a load on the showcase increases, an indoor temperature is reduced by the air-conditioning apparatus so that a load on the showcase is reduced, reduction in operating efficiency of the refrigerating machine is suppressed, and an improvement in energy saving quality is achieved.

Abstract: Disclosed is a method for controlling noise reduction of an air conditioner comprising the steps of: (a) stopping a compressor, when the air conditioner is stopped under the condition that the compressor and an outdoor fan are operated; and (b) stopping the outdoor fan after a designated time after a point in time when the compressor is stopped in the step (a) elapses, thus reducing the size and duration of noise generated by the flow of the refrigerant due to a difference of inner pressures in the air conditioner and allowing the noise at a designated frequency band generated by the flow of the refrigerant, which causes unpleasantness to users, to be concealed by noise generated by the operation of the outdoor fan. Accordingly, the method of the present invention increases reliability of air conditioner products.

Abstract: In an apparatus and a method for controlling operation of a compressor, by removing deviation generated by resistance and inductance and removing an error in a stroke estimation value of a compressor, operation of the compressor can be accurately controlled. The apparatus includes a counter electromotive force detector for detecting a counter electromotive force generated at a motor of a compressor. A stroke calculator calculates a stroke estimation value of the compressor on the basis of the counter electromotive force, and a stroke controller controls a stroke of the compressor by varying a voltage applied to the motor on the basis of the calculated stroke estimation value and a stroke reference value.

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: A compressor torque estimate device is used for a variable displacement compressor whose displacement is variable based on a compressor control signal for estimating a compressor torque of the compressor. The compressor torque estimate device includes a torque calculator and a corrector. The torque calculator calculates a torque required for driving the compressor based on the compressor control signal, thereby obtaining a calculated torque. The corrector corrects the calculated torque by a procedure of first-order lag, thereby obtaining a corrected torque. The corrector also estimates the corrected torque to be the compressor torque.

Abstract: A novel pump pressure limiting method for preventing coolant in a cooling system from reaching pressures that exceed predetermined system coolant pressure limits. The method includes reducing the system coolant pressure, as needed to prevent system over-pressurization, by reducing the operational speed of a coolant pump used to pump the coolant through the system. In one embodiment, the system coolant pressure is determined directly, by measurement of the pressure of the coolant in the system typically using pressure sensors. The operational speed of the coolant pump is then reduced until the system coolant pressure decreases to within the predetermined pressure limits. In another embodiment, the system pressure is determined indirectly, by obtaining pressure-indicating data such as coolant temperature. The coolant system pressure is then correlated with the coolant temperature or other data and then the operational speed of the coolant pump is reduced accordingly.

Abstract: An automatic stop/start controller for an engine, having an air conditioner which employs a coolant or driving force of the engine to control the air in a driver's compartment. The engine can be stopped and started without operation of an ignition key. After a predetermined automatic stop condition is satisfied and the engine is automatically stopped, a control unit maintains the engine in a stopped state as long as the duration of an automatic stop of the engine is shorter than an automatic stop maximum time set based on air temperature at an inlet of the air conditioner.

Abstract: An electric compression device has a motor section and a compressor section contained in a housing, an inverter attached to the outer surface of the housing, and a temperature measurement device for measuring a temperature of the inverter. In a stopped state of a refrigeration cycle system, a control unit drives the motor section when the temperature of the inverter, measured by the temperature measurement device, exceeds a predetermined temperature.

Abstract: A compressor is controlled by generating and storing a compressor operation log. In addition, a compressor operation is selected from the compressor operation log in response to a sensor failure. Furthermore, the compressor is modulated according to the selected compressor operation in response to the sensor failure.

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: A method for operating a vapor compression system includes the steps of providing a vapor compression system having a compressor circuit including a compressor having an inlet port and an outlet port, a circuit incorporating the compressor, a condenser, an evaporator and an expansion device for sequentially generating a cooling refrigerant for cooling a stream of air so as to provide a dehumidified cooled stream of air, and a reheat refrigerant for heating the dehumidified cooled stream of air to provide a reheated dehumidified stream of air; controlling discharge pressure from the compressor outlet so as to increase discharge pressure from the compressor outlet. Furthermore, system dehumidification performance is improved in terms of latent capacity boost, undesired sensible capacity reduction, latent efficiency enhancement, and recovery of supply air temperature to a desired level.

Abstract: The present invention discloses an apparatus and method for controlling an operation of an outdoor unit which can efficiently control the outdoor unit by mounting sensors on the outdoor unit. The apparatus for controlling the operation of the outdoor unit includes: a pressure sensor for sensing a pressure of refrigerants in an outlet of a compressor of the outdoor unit; a temperature sensor for sensing a temperature of the refrigerants in an outlet of a condenser; and a microcomputer for comparing the pressure from the pressure sensor and the temperature from the temperature sensor with optimal pressure and temperature ranges, and controlling operation conditions of at least a blast fan and the compressor in the outdoor unit to be inversely proportional to each other according to the comparison results.

Abstract: There is provided a cooling apparatus which can prevent an abnormal increase in pressure of a high side at the time of starting. The cooling apparatus comprises: a refrigerant circuit which uses carbon dioxide as a refrigerant; and a control device which controls a speed of rotation for the compressor between predetermined lowest and highest speeds. The control device runs the compressor by holding a predetermined start-time holding speed of rotation lower than the lowest rotational speed for a predetermined time before the lowest rotational speed is reached after the compressor is started.

Abstract: There is provided a cooling apparatus which can improve a cooling efficiency while preventing an abnormal increase in pressure of a high side. The cooling apparatus comprises: a refrigerant circuit which uses carbon dioxide as a refrigerant; a control device which controls a speed of rotation of the compressor between predetermined lowest and highest speeds; and a cooled state sensor which detects a cooled state in a refrigerator main body to be cooled by an evaporator included in the refrigerant circuit. The control device increases a highest speed of rotation of the compressor if a temperature in the chamber of the refrigerator main body detected by the cooled state sensor is low.

Abstract: It is described a cooling system for cooling an ambient to be cooled, a cooler and a method of controlling a cooling control system. The cooling control system comprises a variable capacity compressor and a controller, the controller measuring the load of the compressor and verifying the temperature condition in the cooler ambient and actuating on the cooling capacity of the compressor. The method of controlling a cooling control system comprises the steps of: measuring, throughout the cooling cycle, the load (Ln) of the compressor, the temperature condition in the cooling ambient and altering the cooling capacity of the compressor, according to the values of the load (Ln) and the temperature condition in the cooled ambient.

Abstract: An air conditioning apparatus includes a refrigerating cycle supplying the supercritical refrigerant pressurized by the variable displacement compressor to the outdoor heat exchanger, the expansion valve and the indoor heat exchanger, in sequence and subsequently return the supercritical refrigerant to the variable displacement compressor. The apparatus further includes a displacement control unit that establishes a limit value derived from the engine speed and further controls a discharge volume of the compressor prior to the control in the opening degree of the expansion valve, on a basis of the so-established limit value.

Abstract: In a vehicular air conditioning control apparatus having a compressor and an electric cooling fan of an externally controlled type, a fan motor control for increasing fan motor load is carried out in a compressor discharge capacity region lower than in normal control in below-listed cases. (1) When a requested cooling performance is predicted to increase. (2) When a vehicle is brought into an idling state. (3) In cool down in which a requested cooling performance is predicted to increase to be equal to or larger than a set value, or when a vehicle is brought into an idling state.

Abstract: An apparatus for controlling a variable displacement compressor has an information detector and a controller. The information detector detects information about the thermal load on the refrigeration circuit. The controller determines a target value that reflects the displacement of the compressor based on the information about the thermal load detected by the information detector, and outputs the target value as a command value. When determining that the compressor is in a heavy load state based on information about a load on the compressor, the controller changes the command value to a value that causes the displacement of the compressor to become smaller than a displacement that corresponds to the determined target value.

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: Disclosed is a method for controlling an air conditioner. In particular, driving modes of elements, namely sucking/discharge compressure, of the compressor in operation are determined so that variable means are controlled to ensure for the elements of the compressor to be within predetermined value ranges in safe area. According to the present invention, vibrations/noises that usually occur when the compressor is in unstable area are greatly reduced and thus, the compressor can be protected from damages.

Abstract: An apparatus and a method are disclosed for controlling operation of a compressor capable of greatly decreasing a stroke estimation error of a compressor and controlling operation of the compressor accurately and precisely. The method includes calculating a first stroke estimation value of a compressor on the basis of current, a voltage applied to a motor of a compressor and preset parameters of the motor. Detecting a counter electromotive force of the motor and calculating a second stroke estimation value of the compressor on the basis of the detected counter electromotive force value.

Abstract: The present invention aims to prevent the occurrence of liquid compression at the second rotary compression element before it happens while improving the compression efficiency with an intermediate cooling circuit in a refrigerant cycle apparatus which comprises an internal high-pressure type multi-stage compression compressor, and the invention is summarized in that the apparatus comprises an intermediate cooling circuit which allows refrigerant discharged from the first rotary compression element of a compressor to dissipate heat, where a microcomputer performs control on the number of revolutions of the compressor to maintain the temperature/pressure of refrigerant so that the refrigerant does not condense at the output of the intermediate cooling circuit, where such a control is done in response to outputs from an outside-air temperature sensor, a refrigerant temperature sensor, and a signal from a controlling apparatus of a refrigerating apparatus body.

Abstract: An electromagnetic clutch for a compressor includes a rotor, an armature, an electromagnetic coil for bringing the rotor into contact with the armature and for separating the rotor from the armature, and a temperature detection device, such as a temperature fuse or a temperature switch, or both, for detecting an excessive increase in temperature ascribed to slippage between the rotor and the armature or a temperature increase of refrigerant discharged from the compressor. An electric circuit of the temperature detection device is separated from the electric circuit of the electromagnetic coil. An abnormal condition may be accurately detected by the separate circuit structure, and a proper response to the abnormal condition may be taken quickly.

Abstract: A compressor torque estimate device is used for a variable displacement compressor whose displacement is variable based on a compressor control signal for estimating a compressor torque of the compressor. The compressor torque estimate device includes a torque calculator and a corrector. The torque calculator calculates a torque required for driving the compressor based on the compressor control signal, thereby obtaining a calculated torque. The corrector corrects the calculated torque by a procedure of first-order lag, thereby obtaining a corrected torque. The corrector also estimates the corrected torque to be the compressor torque.

Abstract: A cooling system includes multiple cooling fans, each driven by a corresponding fan motor controller. Each fan motor controller includes electronic commutation circuitry that is responsive to a modulated signal to control the speed of the associated motor and fan. The controller for one motor includes a microcontroller that receives a single control signal from an external control unit and translates that control signal into the modulated signals provided to all of the other motor controllers. In one embodiment, the microcontroller can adjust the duty cycle of the modulated control signals, and can stagger the on-off times of the signals to minimize conducted RFI emissions.

Abstract: In an air conditioner, a target compressor rotation speed is determined based on a target air temperature, which represents an air conditioning load, when an electric compressor is started from a stop state. Thus, an evaporator air temperature can be approximated to a target evaporator air temperature, more quickly as compared with a control method where an incremental rotation speed is added to a present rotation speed of the electric compressor, that is, 0 rpm. Accordingly, a large cooling capacity can be obtained for a short time period. Thus, an air temperature in a compartment can be quickly reduced to a comfortable temperature, when the air conditioner is started, for example.

Abstract: A method for driving a hybrid compressor of an air conditioning system of a vehicle is provided. The vehicle includes a first drive source, and the air conditioning system includes an evaporator. Moreover, the hybrid compressor includes a second drive source, and the hybrid compressor is driven by the first drive source via an electromagnetic clutch or the second drive source, or combination thereof. The method includes the steps of engaging the electromagnetic clutch, detecting a temperature of air dispensed from the evaporator, and disengaging the electromagnetic clutch when the temperature of the air is equal to a predetermined temperature. The method also includes the step of activating the second drive source. Specifically the step of disengaging the electromagnetic clutch when the temperature of the air is equal to the predetermined temperature and the step of activating the second drive source is performed simultaneously or substantially simultaneously.

Abstract: An inverter device for variably controlling an operating frequency of an electric motor, which drives a compressor in a refrigerating cycle. the inverter includes a box-like resin case, having a metal film for shielding being applied or plated on a surface thereof and having a step portion on which a terminal block for the motor is arranged. A first substrate having mounted thereon power semiconductor devices constituting a converter and an inverter so as to be immersed in gel, and the first substrate is mounted in the case and brought into proximity of radiation fins at a reverse surface thereof. A second substrate having mounted thereon interface connectors into which signals from detection sensors for temperatures and pressures in the refrigerating cycle are input and photo-couplers for transmitting the input signals, and the second substrate is mounted in the case above the first substrate.

Abstract: Disclosed herein is an air conditioning unit and method of operating the same. The air conditioning unit has a power level control unit (6) for controlling the level of power supplied to a motor (2a) of a compressor. The power level control unit (6) is comprised of a first supplying unit (6a) for supplying first level power to the compressor motor (2a), and a second supplying unit (6b) for supplying second level power to the compressor motor (2a). If an operation cycle of the compressor corresponds to a loading operation, the power level control unit (6) supplies first level power for compressing a cooling agent through the first supplying unit (6a). Further, if an operation cycle of the compressor corresponds to an unloading operation, the power level control unit (6) supplies second level power less than the first level power through the second supplying unit (6b).

Abstract: In an air conditioner for a vehicle, when a target rotation speed of an electric compressor calculated by a target rotation speed calculating means is higher than an upper limit set by an upper limit setting means and a noise level is reduced from a level equal to or higher than a predetermined noise level to a level lower than the predetermined noise level, an inverter controls the compressor to stop for a predetermined period of time and subsequently increase rotation speed to the upper limit. Since the compressor is stopped for the predetermined period of time, the rotation speed of the compressor is controlled without detecting a rotational position of the compressor. Therefore, when the target rotation speed is higher than the upper limit and the noise level is decreased lower than the predetermined noise level, an actual rotation speed of the compressor is immediately decreased.