Abstract: A method for operating a voltage source inverter is provided, the method including inducing, via the voltage source inverter, a DC current at a load device to obtain a load voltage value; determining an ideal switching-averaged voltage based on a switching modulation scheme; determining a combined semiconductor voltage drop and deadtime effect; and adjusting the switching modulation scheme such that a resulting ideal switching-averaged voltage is based on the combined semiconductor voltage drop and deadtime effect and the load voltage value.

Abstract: A method of operating a compressor includes obtaining a mechanical angle and an angular speed of a rotor, determining an amplitude of a fundamental harmonic of a periodic load torque exerted on the rotor based at least in part on the mechanical angle and a harmonic series representation of the periodic load torque, obtaining a speed error by subtracting the angular speed from a reference angular speed, determining a DC component of the periodic load torque based at least in part on a speed error and a closed loop feedback control algorithm, calculating an electromagnetic torque using the DC component of the periodic load torque and the amplitude of the fundamental harmonic of the periodic load torque, and operating the electric motor to generate the calculated electromagnetic torque on the rotor.

Abstract: A motor system can include a motor configured to be operated according to at least a portion of an operation cycle specifying at least one target speed for the motor and a controller configured to obtain an estimated winding resistance of the motor, wherein the estimated winding resistance is determined based at least in part on an estimator gain factor, and wherein the estimator gain factor is inversely dependent on a speed of the motor; wherein the at least one target speed comprises at least one low speed such that at least a portion of the operation cycle is a low speed portion of the operation cycle, the at least one low speed having a speed of less than about 10 percent of a maximum speed of the operation cycle.

Abstract: A method of operating a rolling piston compressor includes determining a pressure difference (?P) between a discharge pressure (Pd) within a compression volume and a suction pressure (Ps) within a suction volume; determining a pressure ratio (rp) equal to the discharge pressure (Pd) over the suction pressure (Ps); estimating a discharge pressure (Pd) based at least in part on the pressure difference (?P) and the pressure ratio (rp); determining that the discharge pressure (Pd) is greater than a predetermined pressure limit (Pd-limit); and lowering a target speed (?target) of the rolling piston compressor.

Abstract: A method for operating an appliance motor includes receiving a target speed for the motor, obtaining a power limit for the motor, determining an inverter current limit based at least in part on the target speed and the power limit, determining an inverter output current to achieve the target speed, wherein the inverter output current is limited to the inverter current limit, and supplying the motor with the inverter output current.

Abstract: A method for operating a voltage source inverter is provided, the method including inducing, via the voltage source inverter, a DC current at a load device to obtain a load voltage value; determining an ideal switching-averaged voltage based on a switching modulation scheme; determining a combined semiconductor voltage drop and deadtime effect; and adjusting the switching modulation scheme such that a resulting ideal switching-averaged voltage is based on the combined semiconductor voltage drop and deadtime effect and the load voltage value.

Abstract: A motor system can include a motor configured to be operated according to at least a portion of an operation cycle specifying at least one target speed for the motor and a controller configured to obtain an estimated winding resistance of the motor, wherein the estimated winding resistance is determined based at least in part on an estimator gain factor, and wherein the estimator gain factor is inversely dependent on a speed of the motor; wherein the at least one target speed comprises at least one low speed such that at least a portion of the operation cycle is a low speed portion of the operation cycle, the at least one low speed having a speed of less than about 10 percent of a maximum speed of the operation cycle.

Abstract: A motor system can include a motor, the motor including at least a rotor, and a controller configured to operate the motor. The controller can be configured to perform operations for operating the motor.

Abstract: A method for operating a variable capacity drive circuit of a compressor includes operating first and second four-quadrant switches in a first state in which the first four-quadrant switch is closed and the second four-quadrant switch is open such that a voltage seen by the motor is equal to an AC line voltage. The method also includes operating the first and second four-quadrant switches in a second state where the first four-quadrant switch is open and the second four-quadrant switch is closed such that the voltage seen by the motor is to zero. Further, the method includes providing a positive firing angle and a negative firing angle for defining when the first and second four-quadrant switches are operated in each of the first and second states. Moreover, the method also includes transitioning between the first and second states using the firing angles at a switching frequency determined by the AC line voltage frequency.

Abstract: A linear compressor or method of operation may provide for driving a motor of the linear compressor to a reference current and detecting a sampled current during driving the motor. The linear compressor or method may also provide for calculating a variance in current using the sampled current, determining the calculated variance exceeds a variance threshold, and restricting the reference current based on determining the calculated variance exceeds the variance threshold.

Abstract: A method for operating a variable capacity drive circuit of a compressor includes operating first and second four-quadrant switches in a first state in which the first four-quadrant switch is closed and the second four-quadrant switch is open such that a voltage seen by the motor is equal to an AC line voltage. The method also includes operating the first and second four-quadrant switches in a second state where the first four-quadrant switch is open and the second four-quadrant switch is closed such that the voltage seen by the motor is to zero. Further, the method includes providing a positive firing angle and a negative firing angle for defining when the first and second four-quadrant switches are operated in each of the first and second states. Moreover, the method also includes transitioning between the first and second states using the firing angles at a switching frequency determined by the AC line voltage frequency.

Abstract: A method of operating a motor driving a rotating member includes directing rotation of the rotating member at the motor at an initial speed, determining a first frequency of a first noise component generated by the rotating member at the initial speed, determining a second noise component having a second frequency phase shifted 180° with respect to the first frequency, determining a torque modifier of the motor to generate the second noise component from the motor, and directing activation of the motor according to the determined torque modifier.

Abstract: A linear compressor and methods of operation, for example, to control extension of the linear compressor, are provided herein. A method may include supplying a time varying voltage to a motor of the linear compressor, determining an uneven fatigue condition at the linear compressor, and applying a limiting force at the motor in a negative axial direction in response to the determining step.

Abstract: A method of operating a rolling piston rotary compressor includes obtaining an angular position and an angular speed of a rolling piston of the compressor, for example, using a tachometer or shaft encoder or observer. The method further includes obtaining an electromagnetic torque applied by an electric motor that is mechanically coupled to the rolling piston. The method further includes calculating a load torque exerted on the rolling piston based on these obtained values by using a load torque observer model that is formulated using known geometries of the compressor and thermodynamic models for the gas compression process. The operation of the electric motor is then adjusted such that the electromagnetic torque applied by the motor is equivalent to the calculated load torque such that noise and vibrations are minimized.

Abstract: A linear compressor and methods of operation, for example, to detect polarity for the linear compressor are provided herein. The method may include supplying an initial time varying voltage to the motor of the linear compressor at an assumed polarity; estimating a first acceleration of the motor of the linear compressor when the motor is at a bottom dead center position; estimating a second acceleration of the motor of the linear compressor when the motor is at a top dead center position; comparing the first acceleration to the second acceleration; and determining whether the assumed polarity is correct based on the comparison.

Abstract: A linear compressor and methods of operation, for example, to control extension of the linear compressor, are provided herein. A method may include supplying a time varying voltage to a motor of the linear compressor, determining an uneven fatigue condition at the linear compressor, and applying a limiting force at the motor in a negative axial direction in response to the determining step.

Abstract: A linear compressor and methods of operation, for example, to detect polarity for the linear compressor are provided herein. The method may include supplying an initial time varying voltage to the motor of the linear compressor at an assumed polarity; estimating a first acceleration of the motor of the linear compressor when the motor is at a bottom dead center position; estimating a second acceleration of the motor of the linear compressor when the motor is at a top dead center position; comparing the first acceleration to the second acceleration; and determining whether the assumed polarity is correct based on the comparison.

Abstract: A method of operating a rolling piston rotary compressor includes obtaining an angular position and an angular speed of a rolling piston of the compressor, for example, using a tachometer or shaft encoder or observer. The method further includes obtaining an electromagnetic torque applied by an electric motor that is mechanically coupled to the rolling piston. The method further includes calculating a load torque exerted on the rolling piston based on these obtained values by using a load torque observer model that is formulated using known geometries of the compressor and thermodynamic models for the gas compression process. The operation of the electric motor is then adjusted such that the electromagnetic torque applied by the motor is equivalent to the calculated load torque such that noise and vibrations are minimized.

Abstract: A method of operating a synchronous motor includes using a rotor angle observer model to calculate an observed rotor angle and a speed estimator model to calculate an observed angular speed of the rotor. The observed rotor angle may be used to ensure that the stator magnetic field generated by the stator is oriented 90° ahead of the rotor magnetic field. The observed angular speed may be used to regulate the motor operation to achieve the desired speed.

Abstract: A method of operating a compressor includes obtaining a harmonic series representation of speed variation as the rotor rotates through each revolution. The method includes regulating an electric motor to compensate for or cancel out the periodic speed variation. Specifically, the method includes calculating an electromagnetic torque using a torque control input model based on the speed error and the harmonic series representation of the speed error. The operation of the electric motor is then adjusted such that the electromagnetic torque applied by the motor cancels out the speed variation such that noise and vibrations are minimized.