Abstract: A monitoring system for monitoring operation of a refrigerant-cycle system is disclosed. An electrical sensor measures an electrical quantity indicative of power consumption of a component of the refrigerant-cycle system. A processing system selectively identifies a condition indicative of an airflow restriction through the refrigerant-cycle system based on the power consumption of the component.

Abstract: A monitoring system for monitoring operation of a refrigerant-cycle system is disclosed. A differential pressure sensor measures a pressure difference between: (i) air at a first location upstream of an evaporator of the refrigerant-cycle system; and (ii) air at a second location downstream of the evaporator of the refrigerant-cycle system. An electrical sensor measures an electrical quantity indicative of power consumption of the refrigerant-cycle system. A processing system determines whether airflow through the evaporator is restricted based on the pressure difference. The processing system calculates an efficiency of the refrigerant-cycle system based on the power consumption of the refrigerant-cycle system.

Abstract: A monitoring system for monitoring operation of a refrigerant-cycle system is disclosed. A plurality of sensors measure operating characteristics of the refrigerant-cycle system. The refrigerant-cycle system includes a condenser unit and an evaporator unit. The condenser unit includes a condenser and a compressor. The evaporator unit includes an evaporator and a fan. A processing system receives the measurements from the plurality of sensors and outputs data regarding operation of the refrigerant-cycle system to a remote monitoring system.

Abstract: A cooling device and to a method for controlling a cooling device for vehicles is provided, the cooling device including a refrigerant compressor, a condenser downstream of the refrigerant compressor in the flow direction of the refrigerant, a first evaporator downstream of the condenser for cooling air to be supplied to the passenger compartment, a second evaporator arranged parallel to the first evaporator for cooling an electric accumulator, and a control unit which is configured to control the refrigerant compressor as a function of the cooling demands for the passenger compartment and/or the electric accumulator on the basis of the higher cooling demand requirement. The cooling device may further include electric valves between the condenser and the first and second evaporators to control a cooling capacity of the first and/or second evaporator to meet the cooling demands of the passenger compartment and/or the electric accumulator.

Abstract: A cooling system includes a cooling loop that includes a reservoir. The reservoir has a level sensor that is configured to provide a level signal indicative of a coolant level within the reservoir. A temperature sensor is in communication with the cooling loop and is configured to provide a temperature signal. A controller is in communication with the level sensor and the temperature sensor. The controller has a coolant density data. The controller is configured to correct the level signal based upon the temperature signal and detect a leakage condition of the cooling system. A method of determining a coolant amount within a cooling system includes the steps of determining an amount of coolant having a temperature-variable density, determining a coolant temperature, correcting the coolant amount based upon the coolant temperature, and comparing the corrected coolant amount to a desired coolant amount to detect a coolant leakage condition.

Abstract: A bottle-shaped container comprises at least three components. The first component is injection molded, has a desired shape, side walls, an opening at a top and a neck portion that connects the side walls to the top. The ratio of a diameter of the opening to a largest length of the inside wall is no greater than 0.75. The second component is a sleeve that abuts the inside side walls. The sleeve comprises side walls and a bottom section. An outside portion of the sleeve is fixed to inside side walls by a notch or lip located at an inside portion of the neck. The third component is a bottom that abuts an outside portion of the bottom section of the sleeve. A portion of each end of bottom is fixed to a portion of an undercut of a bottom of the bottle side walls.

Abstract: A cooling and heating control method of a multi type air conditioner in which a target pressure of a compressor is adjusted based on conditions of respective indoor units so as to reduce power consumption is provided. The cooling control method includes determining the indoor unit desired to execute power saving control, judging whether or not a difference between a temperature of a space in which the indoor unit desired to execute power saving control is located and a set temperature of the indoor unit is less than a reference value, raising a target evaporation temperature of the indoor unit upon judging that the difference is less than the reference value, comparing an evaporation temperature of the indoor unit with the raised target evaporation temperature, and raising an evaporation pressure of a compressor, when the evaporation temperature of the indoor unit is lower than the raised target evaporation temperature.

Abstract: Cooling apparatus is provided which comprises a mechanical refrigerator and a heat pipe. The mechanical refrigerator has a first cooled stage and a second cooled stage, the second cooled stage being adapted to be coupled thermally with target apparatus to be cooled. The heat pipe has a first part coupled thermally to the first stage of the mechanical refrigerator and a second part coupled thermally to a cooled member which may comprise the second stage of the mechanical refrigerator. The heat pipe is adapted to contain a condensable gaseous coolant when in use. An example coolant is Krypton. The apparatus is operated in a first cooling mode in which the temperature of the cooled member causes the coolant within the second part of the heat pipe to be gaseous and the temperature of the first stage causes the coolant in the first part to condense, whereby the cooled member is cooled by the movement of the condensed liquid is from the first part to the second part of the heat pipe.

Abstract: A refrigeration appliance, such as a household refrigerator that can include freezer and fresh food compartments, includes operating components that can be controlled so as to allow a user to select for implementation at the refrigeration appliance modes of operation that can optimize the performance of the refrigeration appliance with respect to selected operating objectives. The refrigeration appliance also can include a respective actuating device corresponding to each mode of operation that is available for selective implementation by the user upon the activation of the respective actuating device and a controller configured to direct operating commands to the one or more operating components in response to the activation of a respective actuating device, causing the one or more operating components to operate in a manner so as to selectively implement at the refrigeration appliance the mode of operation corresponding to the respective actuating device activated.

Abstract: An apparatus including a magnetic attenuator substantially surrounding a non-rotatable portion of the apparatus.

Abstract: A system and method for removing condensate from an air conditioning unit is disclosed. The system comprises a conduit including an outlet portion that is connected to a chamber of a housing of the unit at a first location. The conduit includes an inlet portion that is connected to the chamber at a second location where condensate accumulates. A gravitational separator portion which extends below the second location is connected to the outlet portion and the inlet portion. A draining portion having an orifice for allowing condensate to exit the conduit is connected to the gravitational separator portion below the second location. The first location is chosen such that during operation of the unit the pressure at the first location is less than the pressure at the second location.

Abstract: An auxiliary power system that is coupled a truck is described. The auxiliary power system pumps a fluid material housed by a truck hydraulic tank and bypasses the truck engine to affect a pump that offload the fluid material. The auxiliary power system includes a housing, an auxiliary engine, a pump, a suction line, a pressure line, and an offload control module. A method for configuring an auxiliary power system to bypass a truck engine is also described. The method includes controlling a pump that is operatively coupled to an auxiliary engine with an offload control module, in which the pump is powered by the auxiliary engine.

Abstract: The air conditioner includes indoor units, at least one outdoor unit connected to the indoor units via a refrigerant pipe to drive the indoor unit using a first signal, a central controller to control operations of the outdoor unit and the indoor units using a second signal, the second signal having a frequency band spaced from that of the first signal, and a communication apparatus installed in the outdoor unit or one of the indoor units connected to the outdoor unit to communicate with the central controller using the second signal, whereby signals with different frequency bands can be used upon communication between the outdoor unit and the indoor unit and communication between the outdoor unit or indoor unit and the central controller, so as to reduce signal interference and enhance efficiency of a system operation, resulting in improving safety of the system.

Abstract: Systems and methods for remote monitoring of a transport refrigeration system are provided. In one embodiment, a transport refrigeration system (“TRS”) is provided that includes a transport refrigeration unit (“TRU”) and a generator set (“genset”). The TRU includes a refrigeration circuit and a TRS controller. The genset includes a power generator a genset controller, a TRU remote monitoring device configured to obtain TRU telemetry data and a genset remote monitoring device configured to obtain genset telemetry data. The TRS genset is configured to send the TRS telemetry data to an external server.

Abstract: An air conditioner and a method of controlling the same are provided. The air conditioner and the method analyze a power used pattern according to input power data, compute expected power according to the pattern to dynamically control power, so the power consumption is expected and controlled according to the pattern to stably control a power amount without repeating unnecessary control instead of collective and simple control according to a fixed target. Since an expected amount of the power consumption can be computed, power control is easy and energy consumption is reduced.

Abstract: An air-conditioning system performance monitor measures the temperature of air on either side of the evaporator. Then a microcontroller means calculates the temperature drop in the air flowing across the evaporator. If the temperature drop is less than a predetermined threshold temperature, the microcontroller means alerts the house owner via display units, alarm, internet enabled devices and cell phones to call for service. This unit can be used on central air-conditioning systems, window air-conditioning systems and automobile air-conditioning systems.

Abstract: A system or a method for performing capacitive sensing of humidity/liquid, primarily in conductive or non-conductive liquid/gas mixtures, having a control unit and at least first and second sensor electrodes, the capacity between the first and the second electrodes being measured,. To measure humidity/liquid in a circulating gas/liquid mixture at least one of the sensor electrodes is formed as a tube which is placed in the liquid/gas mixture. Based on the capacitive measurements, a calculation of at least one dataset for control of a second system is performed. The tube can be more or less filled up with liquid or gas and the capacity can be measured as it depends on the content around or inside the tube, and if a dry gas is there will be one value of capacity and in a situation where the gas is being replaced by liquid, the capacity value will change rapidly.

Abstract: A transport refrigeration system includes an engine, a generator set, and a refrigeration system. An electronic control unit and/or a reefer controller are configured to obtain an engine operation condition value and a transport refrigeration system operation value respectively. A genset controller is configured to determine a fuel efficient engine operation speed that is associated with the engine and/or transport refrigeration system operation condition value. The genset controller instructs the electronic control unit to operate the engine at the fuel efficient operation speed.

Abstract: A method of controlling an air conditioning compressor in a heating ventilation and air conditioning system having a evaporator including a phase change material is presented. The method includes the steps of measuring an evaporator output air temperature, determining a state of charge value by calculating a difference between an estimated refrigerant temperature based on the evaporator output air temperature and a phase change material freeze temperature and integrating this difference over time and operating the air conditioning compressor to maintain the state of charge value between an upper and lower limit. A method of recovering braking energy in a vehicle containing a heating ventilation and air conditioning system having the evaporator including the phase change material is also presented.

Abstract: An object of the present invention is to maintain a heating amount constant when a compressor is heated at the time of shutdown of the compressor, regardless of the influences of production tolerance and environment variations. An inverter control unit causes an inverter to generate a high-frequency AC voltage having a de-energized section in which a voltage applied from the inverter to a motor is zero between a section in which the voltage is positive and a section in which the voltage is negative. At this time, the inverter control unit detects a value of a current flowing to the inverter in a detection section residing from immediately before a start of the de-energized section to immediately after an end of the de-energized section, and causes the inverter to generate a high-frequency AC voltage adjusted according to the detected current value.

Abstract: Automated control of a cooling system cooling at least one electronic component is provided. The control includes monitoring over a period of time variation of an operational variable of the cooling system or of the at least one electronic component, and based, at least in part, on variation of the operational variable over the period of time, automatically determining whether to adjust control of the cooling system to limit variation of the operational variable. In one implementation, depending on the variation of the operational variable, and whether control of the cooling system has been previously adjusted, the method may further include automatically determining a probability of fail or an expected residual life of the cooling system, and responsive to the predicted probability of fail exceeding a first acceptable threshold or the expected residual life being below a second acceptable threshold, automatically scheduling for a cooling system repair or replacement.

Abstract: A secondary coolant refrigeration system powered primarily by a photovoltaic source and by an alternating current (AC) source as a backup is disclosed. The secondary coolant refrigeration system has a pump for pumping secondary coolant fluid through a secondary coolant fluid loop. The system includes a variable frequency drive for controlling the speed of the pump. The variable frequency drive includes drive circuitry configured to provide variable frequency power to the pump via an output interface. The variable frequency drive also includes a first interface configured to receive power from the photovoltaic source and a second interface configured to receive power from the AC source. The circuit is further configured to cause the variable speed drive to be powered by the photovoltaic source when the power received from the first interface is adequate and by the AC source when the power received from the first interface is not adequate.

Abstract: A horizontal suction accumulator generally includes a tank, an inlet tube, and an outlet tube. The tank extends in a horizontal direction and is configured to receive a refrigerant. The refrigerant includes a vapor and a liquid. The tank stores the liquid refrigerant and discharges the vapor refrigerant. The inlet tube supplies into the tank an inlet stream that includes the liquid and vapor refrigerants. The inlet tube extends into the tank and is bent upward at an acute angle. The liquid refrigerant is stored in the tank. The vapor refrigerant is discharged through the outlet tube, which extends offset from the inlet tube and into the tank. The inlet tube defines an inlet opening positioned at a first elevation, the outlet tube defines an outlet opening positioned at a second elevation, and the first and second elevations are substantially the same.

Abstract: The invention relates to a composition including 1,1,1,4,4,4-hexafluorobut-2-ene and 3,3,4,4,4-pentafluorobut-1-ene, as well as to use thereof, in particular as a heat transfer fluid.

Abstract: Systems and methods for handling discrete sensor information in a transport refrigeration system are provided. In one embodiment, a wireless control system for a transport refrigeration system is provided. The wireless control system includes two or more wireless end nodes and a network coordinator. Each of the wireless end nodes is configured to monitor a property of the transport refrigeration system. The network coordinator is configured to manage, command, direct and regulate the behavior of the wireless end nodes. Also, the network coordinator includes a sensor to zone coordinator that is configured to combine sensor data received by the two or more wireless end nodes to control a single transport refrigeration system function of the transport refrigeration system.

Abstract: An air filter, which is intended for installation in an air conditioning system of a vehicle and which exhibits a moisture sensor, is disposed on or at the air filter. The moisture sensor is a component of an electric circuit section, which is arranged on or at the air filter. The moisture sensor is a capacitive sensor, whose capacitance depends on the moisture loading of the air, flowing around the sensor. At least one electric property of the electric circuit section represents the moisture loading on the air filter and the type of air filter.

Abstract: A backup cooling storage system comprising at least one cooling and storage unit configured to cool a liquid supply using a quantity of cooled material when a main chiller of the liquid supply is not operational, and at least one chilling element configured to generate the quantity of cooled material for the at least one cooling and storage unit when the main chiller of the liquid supply is operational. Additional embodiments and methods are further disclosed.

Abstract: A personal thermal regulation system includes a personal liquid cooling garment, wherein the personal liquid cooling garment is configured to circulate a working fluid therein, a membrane evaporator configured to receive circulated working fluid from the personal liquid cooling garment, wherein the membrane evaporator is further configured to evaporate a portion of the received circulated working fluid, and a chemical absorber in fluid communication with the membrane evaporator, wherein the chemical absorber is configured to receive a controlled flow of the evaporated portion of the received circulated working fluid from the membrane evaporator.

Abstract: An accumulator arrangement for use in a cooling system suitable for operation with two-phase refrigerant includes a condenser having a refrigerant inlet and a refrigerant outlet. The accumulator arrangement further includes an accumulator for receiving the two-phase refrigerant therein, the accumulator having a refrigerant inlet connected to the refrigerant outlet of the condenser and a refrigerant outlet. Finally, the accumulator arrangement includes a subcooler having a refrigerant inlet and a refrigerant outlet, the refrigerant inlet of the subcooler being connected to the refrigerant outlet of the accumulators, and the subcooler being arranged at least partially within the interior of the accumulator.

Abstract: A method of forming a passageway in an insulated door of a refrigerator includes the steps of forming a conduit by inserting a mandrel in the space between a door liner and outer skin, filling the space with foam insulation, and removing the mandrel. In one embodiment, the mandrel is encased with a polymeric skin prior to the inserting step, such that, when the mandrel is removed, the skin remains at the boundary of the passageway so formed. In another embodiment, the method includes mounting fluid and/or electrical conduits to an inside surface of the door liner and subsequently injecting the foam insulation to surround the conduits. In yet another embodiment, fluid and/or electrical conduits are mounted to an outer surface of the door liner. A cover is then positioned over the conduits.

Abstract: The invention relates to a mobile apparatus and a method for concrete production, comprising a cooling apparatus for cooling bulk material, in particular aggregates for concrete production. The cooling apparatus (100) comprises a bulk material hopper (110), a wetting apparatus (120) and an air supply apparatus (130). The cooling apparatus has a bulk material feeder (140) for feeding bulk material into the bulk material hopper via a bulk material feeder path (141), the bulk material feeder and the wetting apparatus being adapted and disposed in such a way that bulk material to be fed comes into contact on at least one part of the bulk material feeder path with water that is being discharged from the wetting apparatus.

Abstract: A method for compressing a cryogenic medium, in particular hydrogen, oxygen, nitrogen or argon is described. The cryogenic medium is compressed in two compressor stages from an initial pressure to a final pressure by way of an intermediate pressure, such that the first compressor stage is designed as a cryogenic compressor stage. The cryogenic medium is advantageously compressed to a pressure between 30 and 70 bar in the first compressor stage and in the second compressor stage is compressed to the desired final pressure by means of a hot gas compression.

Abstract: An apparatus and method are developed to improve accuracy of diagnostic tests for A/C systems. In particular, a refrigerant recovery unit may have its hoses pre-charged with a refrigerant to a predetermined pressure or amount before performing the diagnostic tests on the A/C system of the vehicle. For example, a predetermine amount of refrigerant may be injected into the hoses of the refrigerant recovery unit to pre-charge them. The pre-charged hoses of the refrigerant recovery unit may prevent a refrigerant flow from the A/C system to the hoses connected thereto before the diagnostic tests are implemented and thus, improve the accuracy of the diagnostic tests.

Abstract: A beverage cooler has a low voltage DC supply (311) usable by the controller ancillaries, such as lighting (318), the DC supply also providing the supply voltage to a microprocessor (313) which electronically commutates at least one of the motors (305, 306, 307) associated with beverage cooling to provide a required speed or loading. The microprocessor also responds to and controls the cooler ancillaries, such as lighting, temperature and status reporting thereby allowing a reduced component count.

Abstract: An insulated icemaking compartment is provided in the fresh food compartment of a bottom mount refrigerator. The icemaking compartment may be integrally formed with the liner of the fresh food compartment, or alternatively, may be modular for installation anywhere in the fresh food compartment. A removable bin assembly with a front cover normally seals the icemaking compartment to maintain the temperature in the compartment. A cold air duct formed in the rear wall of the refrigerator supplies cold air from the freezer compartment to the icemaking compartment. A return air duct directs a portion of the air from the icemaking compartment back to the freezer compartment. An air vent in the icemaking compartment directs another portion of air into the fresh food compartment. A control system provides for controlling refrigerator functions in a manner that promotes energy efficiency.

Abstract: An insulated icemaking compartment is provided in the fresh food compartment of a bottom mount refrigerator. The icemaking compartment may be integrally formed with the liner of the fresh food compartment, or alternatively, may be modular for installation anywhere in the fresh food compartment. A removable bin assembly with a front cover normally seals the icemaking compartment to maintain the temperature in the compartment. A cold air duct formed in the rear wall of the refrigerator supplies cold air from the freezer compartment to the icemaking compartment. A return air duct directs a portion of the air from the icemaking compartment back to the freezer compartment. An air vent in the icemaking compartment directs another portion of air into the fresh food compartment. A control system provides for controlling refrigerator functions in a manner that promotes energy efficiency.

Abstract: Heat transfer compositions and methods including (a) HFC-32; (b) HFO-1234ze; and (c) either or both of HFC-152a and/or HFC-134a.

Abstract: The present invention relates to a refrigerator unit and/or freezer unit having at least one coolant circuit which has at least one condenser which is connected to at least one damping element which damps vibrations of the condenser and which is arranged between the condenser and at least one part of the unit, wherein the damping element consists of or comprises in part or in full a foamed and/or expanded material, preferably foam, in particular PP or PE, and/or an expanded polymer material, and in particular expanded polypropylene (EPP).

Abstract: An air conditioner having a plurality of compressors and a starting control method thereof, where the plurality of compressors is simultaneously started if a starting load of the air conditioner is smaller than a reference load, and the plurality of compressors is sequentially started if the starting load of the air conditioner is larger than the reference load, thereby simultaneously starting the plurality of compressors at a starting load section in which a starting stability of the compressors is secured, and thus capable of enhancing the cooling and heating performance.

Abstract: The present inventive disclosure is directed generally to an improved automobile air- conditioning system that can be operated while the automobile's engine is not running. In variations, a typical vapor-compression-cycle air-conditioning system is modified to allow the refrigerant compressor to be driven from either of two power sources: (1) from a traditional engine-mounted pulley system, or (2) from a DC-motor powered by an electrical source independent from the engine. In another variation, the air-conditioning system is driven by one or more thermal-electric-cooling (TEC) modules, wherein the TEC-based system is powered by an auxiliary DC-power source that in some variations is powered by, or at least supplemented by, a solar-energy grid.

Abstract: Disclosed are embodiments of heat pump systems and methods for operating such systems in the heating mode while a heat pump operating parameter reaches or is equal to a predetermined operating value at which it is not advisable to use conventional heat pump systems for heating an enclosed structure. In addition to ancillary components, the heat pump systems includes indoor, outdoor and auxiliary heat exchangers, reversing and flow diverting valves, compressors, refrigerant superheat controllers, and auxiliary energy sources. During the heating mode of operation, while the heat pump operating parameter reaches or is equal to the predetermined operating value, the flow of liquid refrigerant through the outdoor heat exchangers is inhibited and is diverted to flow through the auxiliary heat exchangers. Thermal energy from the auxiliary energy source is used for evaporating the liquid refrigerant flowing through the auxiliary heat exchangers.

Abstract: The present disclosure relates to a diagnostic method of a refrigerator using the same, and according to an aspect of the present disclosure, there is provided a diagnostic method of the refrigerator, and the method may include sensing power supplied thereto; determining whether or not a power failure has occurred based on the sensed power; storing power failure occurrence information when it is determined that the power failure has occurred; referring to the power failure occurrence information when the power supply is resumed; storing power failure end information when the power failure occurrence information is found; and providing the power failure occurrence and power failure end information.

Abstract: The present invention relates to a dry cleaning apparatus comprising an arrangement for cooling fluid being used as solvent in the apparatus, and a method for cooling the fluid.

Abstract: Provided is a method for controlling an operation of a refrigerator. Different operation modes are selected according to whether a refrigerator door is opened and closed, and according to an inner temperature and an ambient noise. Freezing capacity of a compressor, the number of rotations of an evaporator fan, and the number of rotations of a condenser fan are varied in conjunction with one another, to reduce a noise.

Abstract: An energy-saving optimized control system for a chiller plant room comprises an industry control computer (1), a flow sensor (4), a temperature sensor (5), an outdoor temperature and humidity sensor (6), a three-phase active power transmitter (7), a water pump variable speed driver (9) and a cooling tower fan variable speed driver (10), which are respectively connected with a programmable controller (2), wherein the programmable controller (2) communicates with the industrial control computer (1) through an industrial Ethernet; and an RS485 communication interface module (3) is connected with chillers and communicates with the industrial control computer (1) through a ModBus protocol. An energy-saving optimized control method for a chiller plant room is also provided.

Abstract: Disclosed herein are a heat pump and a control method thereof. The heat pump includes an outdoor unit including a compressor, an outdoor heat exchanger, and a first expansion valve, an indoor unit including an indoor heat exchanger and a second expansion valve, a hydro unit including a hot water heat exchanger and a third expansion valve, the hydro unit heating or cooling water through heat exchange between a refrigerant and the water, a refrigerant flow path switching member to switch refrigerant flow paths among the compressor, the outdoor heat exchanger, the indoor unit, and the hydro unit such that simultaneous heating and cooling operations and/or simultaneous cooling and heating operations through the indoor unit and the hydro unit are performed in a heat recovery mode to recover and reuse residual heat, and a controller to control the refrigerant flow path switching member such that at least one of the simultaneous operations is performed in the heat recovery mode.

Abstract: Open-loop cooling systems and methods are provided which can be used in many different capacities, including as mobile, personal cooling systems for people engaging in strenuous activities or working in situations where body temperature maintenance is a concern. Efficient use of refrigerant in combination with phase change material provides sustained cooling capability in some embodiments.

Abstract: This invention relates to method for producing cooling in a chiller having an evaporator wherein a refrigerant composition is evaporated to cool a heat transfer medium and the cooled heat transfer medium is transported out of the evaporator to a body to be cooled, wherein said chiller is a centrifugal chiller. The method comprises evaporating a composition comprising E-HFO-1438mzz and optionally HFC-245eb as a refrigerant composition in the evaporator. This invention also relates to a composition comprising: (1) a refrigerant component consisting essentially of HFC-245eb and E-HFO-1438mzz; and (2) a lubricant suitable for use in a chiller; wherein the E-HFO-1438mzz in the refrigerant is at least 1 weight percent. This invention also relates to a centrifugal chiller apparatus containing a refrigerant composition, characterized by said refrigerant comprising E-HFO-1438mzz and optionally HFC-245eb.

Abstract: A cooling system for perishable items.

Abstract: An adder adds a phase ?plus, which is n times a size of 60 degrees, to a phase output from a phase switching unit and outputs the phase as a voltage command phase ?. A voltage generation unit generates voltage command value based on the voltage command phase output by the adder and outputs the command value. A drive-signal generation unit, based on an output from the voltage generation unit generates drive signals corresponding to respective switching elements of an inverter, and outputs respective generated drive signals to the corresponding switching elements of the inverter, and generates a high-frequency AC voltage in the inverter.