An air conditioning system of a vehicle having an internal combustion engine includes a condenser configured to receive refrigerant output by an electric compressor and transfer heat from the refrigerant within the condenser to air passing the condenser. A first evaporator is configured to receive refrigerant from the condenser when a first control valve is open and transfer heat from air passing the first evaporator to the refrigerant within the first evaporator. A first blower is configured to blow air across the first evaporator to a first section of a cabin of the vehicle. A second evaporator is configured to receive refrigerant from the condenser when a second control valve is open and transfer heat from air passing the second evaporator to the refrigerant within the second evaporator. A second blower is configured to blow air across the second evaporator to a second section of the cabin of the vehicle.

An inverter-converter system includes a DC source, a DC to DC boost converter, a DC link capacitor, an inverter circuit, a variable speed electric machine, and a controller. The DC to DC boost converter receives an input DC voltage from the DC source. The inverter circuit converts the variable boosted voltage to an AC voltage to drive the variable speed electric machine. The controller senses a plurality of parameters from the variable speed electric machine, and controls the DC to DC boost converter to boost up the input DC voltage to a variable output voltage based on the plurality of parameters and/or the voltage (or load) needed by the variable speed electric machine. The design of the inverter-converter system can achieve an electrical efficiency and cost savings for the overall system.

The purpose of the present invention is to suppress current distortion due to load-side AC voltage, magnetic saturation (nonlinear) characteristics of a motor, etc., in a power conversion device and a motor drive device. A power conversion device for performing power conversion between an AC power supply and a DC loader between DC power supplies is provided with: an inverter circuit; a current detection means for detecting the AC current of the AC power supply; a voltage controller for generating a command voltage for the inverter circuit on the basis of an AC current signal detected by the current detection means; and a correction unit having a gain with respect to a specific frequency and correcting the command voltage on the basis of the AC current signal. The correction unit is configured to correct the command voltage that has been output from the voltage controller.

A motor drive apparatus which drives a motor includes inverter modules equal in number to phases of the motor. Each of the inverter modules includes a plurality of switching element pairs. Each of the switching element pairs is defined by two switching elements connected in series. In each of the inverter modules, the plurality of switching element pairs are connected in parallel, and each of resistance values of gate resistors connected to the switching elements is set for the corresponding switching element connected thereto.

A compressor driving apparatus, or a home appliance including the same, includes a DC terminal capacitor to store a charge, an inverter to convert direct current associated with the charge of the DC terminal capacitor into an alternating current and output the alternating current to a motor, an output current detection unit to detect an output current flowing in the motor, and an inverter controller to increase a motor speed by starting the motor, and controlling a speed increase of the motor to change based on an increasing slope of a change in an output current detected by the output current detection unit during the speed increase of the motor.

An exemplary system includes a compressor, a condenser, an expander, and an evaporator fluidly coupled to form a vapor-compression circuit, and an electric motor configured to drive the compressor. An inverter having a plurality of switching elements is configured to provide an output voltage to the electric motor through operation of the switching elements. A waste heat recovery circuit is configured to transfer waste heat from the inverter to a load. A controller is configured provide switching commands to the switching elements of the inverter. The controller is further configured to sense a condition of the system, determine a heat production requirement based at least in part upon the system condition, and to vary the number of switching commands per unit time based at least in part upon the heat production requirement.

A refrigerator includes a compressor, an input current detector to detect input current of alternating current (AC) power inputted to the refrigerator, a converter to convert the inputted AC power into direct current (DC) power, a capacitor to store the converted DC power, an inverter to output AC power using the converted DC power for driving of the compressor, a DC terminal voltage detector to detect voltage at two terminals of the capacitor, and a compressor microcomputer to control the inverter and to calculate refrigerator power consumption based on the detected input current and the detected DC terminal voltage. The refrigerator enables simplified power consumption calculation.

A motor driving apparatus and a home appliance including the same. The motor driving apparatus includes a temperature sensing unit to sense a compressor temperature, an inverter including a plurality of switching elements to convert a direct current (DC) voltage into an alternating current (AC) voltage and to supply AC voltage to a motor used to drive the compressor, and a controller to control the inverter. The controller performs control to apply motor preheating current for preheating of the motor during a first period before startup of the motor, and varies depending on the sensed temperature a time during which the motor preheating current is applied or a current application level. A reduction in power consumption during the preheating of the compressor is achieved.

A compressor for a heat transfer circuit includes a variable frequency drive (VFD), an electric motor that rotates a driveshaft, bearing(s) for supporting the driveshaft, a backup gas supply, and a power supply. During a utility power interruption, the backup gas supply operates utilizing DC electrical power generated by a back electromotive force of the electric motor. A method of operating an electric power supply system for a compressor includes operating in a utility power mode and operating in a backup power mode during a utility power interruption. In the utility power mode, AC electrical power is supplied from the VFD to the motor. In the backup power mode, DC electrical power generated in the VFD by a back electromotive force of the motor it used to operate a backup gas supply to supply compressed working fluid to gas bearing(s) of the compressor.

A heat exchanger includes: a water-repellent coating film on part of a surface of the heat exchanger. The surface on which the water-repellent coating film is disposed includes a surface structure including protrusions. D/L<0.36, D/L>0.4?(L/H), D<200, L?D<1000, H>700, 0>1.28?D?10.sup.?2+2.77 ?(L?D)?10.sup.?3?1.1?D.sup.2?10.sup.?5?5.3?(L?D).sup.2?10.sup.?7?9.8?D?(L?D)?10.sup.?6?2.0, and 90?<?<120?, where L is an average pitch of the protrusions in nm, D is an average diameter of the protrusions in nm, H is an average height of the protrusions in nm, and ? is a contact angle of water on a smooth plane of the water-repellent coating film.