Abstract: 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.

Abstract: Permanent magnet rotors for electric motors, particularly electric motors for use in compressors, improve the electromagnetic efficiency of the motor. The rotors can include retention of surface permanent magnets using one or more of retaining features on the motor and/or pole spacers interfacing with corresponding features on a rotor core, the use of a monolithic magnet in the rotor, and/or use of a carbon fiber sleeve. The rotor can include an eddy current shield, disposed on the rotor core, on a surface of the rotor, or located within a sleeve surrounding the rotor. The rotor can be sized such that an air-gap between the rotor and a stator of a motor using the rotor is a predetermined amount that reduces electromagnetic losses such as eddy current losses.

Abstract: An apparatus and method for reducing motor magnetic losses via reduction of temporal harmonics by control of a direct current (DC) link voltage. In one embodiment, the apparatus includes an inverter for converting DC power into alternating current (AC) power for an electric motor. The apparatus also includes a voltage source, which may take form in a rectifier that is configured to provide the DC output voltage to the inverter via a DC link. The voltage source is configured to adjust a magnitude of the DC output voltage based on a rotational speed of the electric motor. The voltage source may also adjust the magnitude of the DC output voltage based on a power output of the inverter.

Abstract: Permanent magnet rotors for electric motors, particularly electric motors for use in compressors, improve the electromagnetic efficiency of the motor. The rotors can include retention of surface permanent magnets using one or more of retaining features on the motor and/or pole spacers interfacing with corresponding features on a rotor core, the use of a monolithic magnet in the rotor, and/or use of a carbon fiber sleeve. The rotor can include an eddy current shield, disposed on the rotor core, on a surface of the rotor, or located within a sleeve surrounding the rotor. The rotor can be sized such that an air-gap between the rotor and a stator of a motor using the rotor is a predetermined amount that reduces electromagnetic losses such as eddy current losses.

Abstract: A method for adjusting compression efficiency for an HVACR system having a variable-frequency drive (VFD) is disclosed. The method includes determining a first compression efficiency, determining an operating point, determining a region of an operating map when a difference between the operating point and a previously determined operating point exceeds a predetermined threshold, adjusting a VFD input to a first input based on the region of the operating map, and controlling the VFD using the first input for a predetermined period of time. The method also includes determining a second compression efficiency and an operation restriction, adjusting the VFD input to a second input based on the operation restriction and a difference between the first compression efficiency and the second compression efficiency, and controlling the VFD using the second input. The method also includes utilizing machine learning control techniques to control several system variables to optimize the compression efficiency.

Abstract: This disclosure is directed to systems and methods for controlling compressor motors, particularly varying the operation parameters of the motor to provide heat to a lubricant of the motor. The operation parameters include one or more of a pulse width modulation switching frequency, a pulse width modulation frequency switching pattern, or a torque/amp ratio of a drive of the compressor. The efficiency of the motor may be reduced to provide heat, with the heat improving lubricant quality and drive efficiency, to increase an overall efficiency of compressor operations. Methods may include determining a lubricant quality, and determining operational parameters that improve lubricant quality.

Abstract: 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.

Abstract: A method for adjusting compression efficiency for an HVACR system having a variable-frequency drive (VFD) is disclosed. The method includes determining a first compression efficiency, determining an operating point, determining a region of an operating map when a difference between the operating point and a previously determined operating point exceeds a predetermined threshold, adjusting a VFD input to a first input based on the region of the operating map, and controlling the VFD using the first input for a predetermined period of time. The method also includes determining a second compression efficiency and an operation restriction, adjusting the VFD input to a second input based on the operation restriction and a difference between the first compression efficiency and the second compression efficiency, and controlling the VFD using the second input. The method also includes utilizing machine learning control techniques to control several system variables to optimize the compression efficiency.

Abstract: Permanent magnet rotors for electric motors, particularly electric motors for use in compressors, improve the electromagnetic efficiency of the motor. The rotors can include retention of surface permanent magnets using one or more of retaining features on the motor and/or pole spacers interfacing with corresponding features on a rotor core, the use of a monolithic magnet in the rotor, and/or use of a carbon fiber sleeve. The rotor can include an eddy current shield, disposed on the rotor core, on a surface of the rotor, or located within a sleeve surrounding the rotor. The rotor can be sized such that an air-gap between the rotor and a stator of a motor using the rotor is a predetermined amount that reduces electromagnetic losses such as eddy current losses.

Abstract: Architectures or techniques are presented that can improve operation of permanent magnet (PM) motors, which can be part of a compressor or other heating, ventilation, and air conditioning (HVAC) device. Such improvements can be achieved by integration of inductive filtering into the motor assembly. A higher overall inductance can reduce current ripple and can further result in a lower total harmonic distortion, reduced power loss, and reduced heat generated. For example a first architecture can include a ferromagnetic core element in the PM motor that can cause a non-torque-producing reluctance path to the shaft. A second architecture can integrate a signal filter, which is customarily external, into a housing of the PM motor. Such can significant reduce costs and provide other advantages. A third architecture can couple an inductor (e.g., of the signal filter) to the shaft. Rotation of the shaft can thus serve to provide additional cooling for the inductor.

Abstract: This disclosure is directed to systems and methods for controlling compressor motors, particularly varying the operation parameters of the motor to provide heat to a lubricant of the motor. The operation parameters include one or more of a pulse width modulation switching frequency, a pulse width modulation frequency switching pattern, or a torque/amp ratio of a drive of the compressor. The efficiency of the motor may be reduced to provide heat, with the heat improving lubricant quality and drive efficiency, to increase an overall efficiency of compressor operations. Methods may include determining a lubricant quality, and determining operational parameters that improve lubricant quality.