A first reactor is provided on the input side of a rectifying circuit that rectifies AC power (on the side of an AC power supply), and on the output side of the rectifying circuit (on the side of a load), first and second capacitors that are connected in series to each other, and first and second switching elements that switch between charging and not charging of the first and second capacitors, respectively, are provided, a second capacitor group in Y-connection, provided with three capacitors, each of which is connected to each phase-terminal of the first reactor on the side of the rectifying circuit, is connected to the midpoint of the first and second switching elements, and the output voltage to the load is boosted, while the on-duty of the first switching element and the on-duty of the second switching element are controlled to be equal to each other.

A selection unit switches between a phase p and a phase n different from the phase p substantially by 180 degrees, and outputs one of them in synchronization with a carrier signal. A voltage-command generation unit generates and outputs three-phase voltage command values Vu*, Vv* and Vw* based on the phase outputted by the selection unit. A PWM-signal generation unit generates three-phase voltage command values Vu*, Vv* and Vw* by correcting the three-phase voltage command values Vu*, Vv* and Vw* outputted by the voltage-command generation unit according to a predetermined method, and generates six drive signals corresponding to switching elements of the inverter based on the three-phase voltage command values Vu*, Vv* and Vw* and the carrier signal. The PWM-signal generation unit outputs the generated drive signals to the corresponding switching elements of the three-phase inverter, to cause the inverter to generate a high-frequency AC voltage.

A system and method for calibrating parameters for a refrigeration system having a variable speed compressor is provided. A compressor is connected to a condenser and an evaporator. A condenser sensor outputs a condenser signal corresponding to at least one of a sensed condenser pressure and a sensed condenser temperature. An inverter drive modulates a frequency of electric power delivered to the compressor to modulate a speed of the compressor. A control module is connected to the inverter drive and determines a measured condenser temperature based on the condenser signal, monitors electric power data and compressor speed data from the inverter drive, calculates a derived condenser temperature based on the electric power data, the compressor speed data, and compressor map data for the compressor, compares the measured condenser temperature with the derived condenser temperature, and updates the compressor map data based on the comparison.

Provided is an air-conditioning apparatus that can suppress occurrence of disproportionation (an autolytic reaction) when HFO1123 refrigerant or a refrigerant mixture containing HFO1123 is applied. The air-conditioning apparatus of the present invention includes a controller 40 controlling at least one of an operation frequency of a compressor 3, an opening degree of an expansion valve 7, and an air amount of a fan sending air to a heat-source-side heat exchanger 9 so that a temperature and a pressure of the refrigerant discharged from the compressor 3 do not exceed threshold values.

An air-conditioning apparatus has a controller that sets the target value of a difference between the temperatures of a secondary-side heat transfer medium at positions before and after a plurality of use side heat exchangers during a rated operation in a heating operation so as to have a larger magnitude than a target value of the difference between the temperatures of the secondary-side heat transfer medium at positions before and after the plurality of use side heat exchangers during a rated operation in the cooling operation.

A method controls discharge temperature of a compressor of a vapor compression system. Using a mapping among discharge temperature, speed of the compressor, and outdoor air temperature, the method determines a desired discharge temperature for a new value of the speed of the compressor. The compressor is abruptly controlled to change the current speed of the compressor to the new value. A valve of the vapor compression system is smoothly controlled, such that the discharge temperature is transitioned to the desired discharge temperature according to a function of time representing a low pass filter with a time constant proportional to the thermal time constant of the compressor.

A motor driving device and an air conditioner including the same are disclosed. The motor driving device includes a rectifier to rectify input AC power, a boost converter to boost power rectified by the rectifier, a capacitor to store a pulsating voltage from the boost converter, an inverter comprising a plurality of switching elements, the inverter transforming AC power, using a voltage across the capacitor, and outputting the transformed power to a motor, a regenerative power consuming unit arranged between the capacitor and the inverter, to consume regenerative power from the motor, and a switching driving unit to output a switching control signal to a switching element in the regenerative power consuming unit while outputting an operation control signal to an inverter controller when the voltage across the capacitor is equal to or higher than a predetermined voltage.

A variable refrigerant package air conditioner is shown that is easy to install in new construction with a unique base that causes collected mixture that overflows to drain outside the building. A control system is shown that has motors and compressor that are pulse width modulated so the air conditioner is infinitely variable while maintaining the highest possible power factor. Dehumidification of outside air occurs as it is mixed with inside air. By gradually approaching a temperature set point and even reheating after dehumidification, moisture is removed from the room.

An air conditioner includes an outdoor unit including a three-phase AC power supply, a compressor that compresses a refrigerant, and an inverter circuit that controls the compressor. The outdoor unit includes a driving microcomputer that drives the inverter circuit, a second diode bridge connected to the inverter circuit, a first relay disposed on a first wiring line, a second relay disposed on a third wiring line, an inrush-prevention resistor, and a third relay connected to the first wiring line and the inrush-prevention resistor. After the compressor stops, the driving microcomputer brings the first relay, the second relay, and the third relay into an off state.

A drive for an air conditioning system includes a converter assembly including a Vienna rectifier having a converter capacitance across a positive DC bus and a negative DC bus; and an inverter assembly including an inverter capacitance across the positive DC bus and the negative DC bus, the inverter capacitance in electrical parallel with the converter capacitance; wherein the converter assembly and the inverter assembly are physically separate assemblies.