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.

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.

A power conversion apparatus, including: an MLC circuit configured to boost an input voltage from a three-phase rectifier; a smoothing capacitor configured to smooth an output of the MLC circuit; an inverter control unit configured to generate a PWM signal; an inverter circuit configured to convert a DC voltage of the smoothing capacitor into an AC voltage based on an input of the PWM signal and to supply the AC voltage to a motor; a boost mode switching unit having at least three boost modes in which a boost level of the input voltage is selected and configured to switch among the at least three boost modes depending on an operation status of the motor determined for the purpose of controlling a refrigeration cycle; and an MLC control unit configured to control the MLC circuit based on the switching by the boost mode switching unit.

A power conversion apparatus includes a converter that rectifies a power-supply voltage applied from an AC power supply, a capacitor connected to an output end of the converter, an inverter connected across the capacitor, and a control device that controls an operation of the inverter. The control device performs a first control of reducing a pulsatile component of a capacitor output current output from the capacitor to the inverter when the load is driven. The first control is control of causing the motor to generate a loss, and the loss that the motor is caused to generate is performed by using a y-axis current.

A power conversion device includes a converter that rectifies a first alternating-current power supplied from an alternating-current power supply and boosts a voltage of the power rectified; a smoothing unit connected to an output end of the converter; and a control unit that controls the converter to cause an input current to the converter to change in accordance with at least one of a first frequency or a second frequency, and that reduces a current flowing to the smoothing unit, the first frequency being a frequency of pulsation of input power to a load unit connected across the smoothing unit, the second frequency being a frequency of pulsation of input power to the converter due to a frequency of the alternating-current power supply.

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 energy efficient heat pump includes a variable capacity compressor and a controller communicatively coupled to the variable capacity compressor. The controller is configured to receive a call for heating, determine an upper discharge pressure limit of the energy efficient heat pump, determine a lower discharge pressure limit of the energy efficient heat pump, determine a target discharge pressure value, where the target discharge pressure value is less than or equal to the upper discharge pressure limit and is greater than or equal to the lower discharge pressure limit, and modulate operation of the variable capacity compressor such that a detected discharge pressure of the heat pump approaches the target discharge pressure value.

A power converter includes: a rectifier unit that rectifies a power supply voltage applied from a commercial power supply; a capacitor connected to an output end of the rectifier unit; an inverter that converts direct-current power output from the capacitor into alternating-current power and outputs the alternating-current power to a device equipped with a motor; and a control unit that performs power supply ripple compensation control of reducing ripple of a capacitor current, which is a charge/discharge current of the capacitor, by controlling the inverter. The control unit determines whether or not a compensation operation by the power supply ripple compensation control is normal and, when determining that the compensation operation is not normal, performs control of reducing a drive speed of the motor or stopping driving of the motor.

A heating, ventilation, and/or air conditioning (HVAC) system includes a compressor, a fan, an inverter configured to drive operation of the compressor, and a controller communicatively coupled to the fan and the inverter. The controller includes a tangible, non-transitory, computer-readable medium with computer-executable instructions that, when executed by processor circuitry, are configured to cause the processor circuitry to determine an operating parameter of the fan in response to an interruption in receiving communication signals from the inverter and operate the fan based on the operating parameter during the interruption.

A drive circuit includes a rectification circuit, a buck converter, and an inverter. the rectification circuit is configured to rectify a first AC voltage signal to generate a rectified voltage signal. The buck converter is configured to downconvert the rectified voltage signal to a DC voltage signal, wherein the DC voltage signal is supplied to a DC bus. The inverter is configured to convert the DC voltage signal to a second AC voltage signal and supply the second AC voltage signal to a compressor motor and to a condenser fan motor. The peak voltages of the second AC voltage signal are less than peak voltages of the first AC voltage signal.