Abstract: Magnets and systems, methods, and techniques for manufacturing magnets are provided. In some embodiments, methods of manufacturing magnets comprise providing a rare earth magnetic body, depositing a bead of dysprosium or terbium metal onto a part of the magnetic body to form a magnet; and heat-treating the magnet. In some embodiments, a magnet is provided comprising a magnetic body and a bead of dysprosium or terbium metal. In some embodiments, the magnetic body contains grains of rare earth magnet alloy, and the bead of dysprosium or terbium metal is deposited onto a part only of a surface of the magnetic body.

Abstract: A brushless motor comprising a frame; a rotor assembly comprising a shaft, a rotor core and a bearing assembly, the bearing assembly being mounted to the frame; and at least one stator comprising a C-shaped stator core, the stator core comprising a back and first and second arms, wherein at least one of the first and second arms includes a protrusion that contacts the frame so as to inhibit radial movement of the stator core towards the rotor assembly.

Abstract: A stator assembly including at least one pair of c-shaped stator cores, each c-shaped stator core having a bobbin, and a winding wound around each bobbin, wherein the windings on each adjacent pair of c-shaped stator cores are wound in opposite directions.

Abstract: A brushless motor comprising a frame; a rotor assembly comprising a shaft, a rotor core and a bearing assembly, the bearing assembly being mounted to the frame; and at least one stator comprising a C-shaped stator core, the stator core comprising a back and first and second arms, wherein at least one of the first and second arms includes a protrusion that contacts the frame so as to inhibit radial movement of the stator core towards the rotor assembly.

Abstract: A stator assembly comprising at least one pair of c-shaped stator cores, each c-shaped stator core having a bobbin, and a winding wound around each bobbin, wherein the windings on each adjacent pair of c-shaped stator cores are wound in opposite directions.

Abstract: Magnets and systems, methods, and techniques for manufacturing magnets are provided. In some embodiments, methods of manufacturing magnets comprise providing a rare earth magnetic body, cold spray depositing a layer of dysprosium or terbium onto the magnetic body to form a magnet, and heat-treating the magnet. Some embodiments provide a magnet comprising a magnetic body and a layer of dysprosium or terbium. In some embodiments, the magnetic body contains grains of rare earth magnet alloy, and the layer of dysprosium or terbium is deposited onto a surface of the magnetic body by a cold spray process.

Abstract: Magnets and systems, methods, and techniques for manufacturing magnets are provided. In some embodiments, methods of manufacturing magnets comprise providing a rare earth magnetic body depositing a bead of dysprosium or terbium metal onto a part of the magnetic body to form a magnet; and heat-treating the magnet. In some embodiments, a magnet is provided comprising a magnetic body and a bead of dysprosium or terbium metal. In some embodiments, the magnetic body contains grains of rare earth magnet alloy, and the bead of dysprosium or terbium metal is deposited onto a part only of a surface of the magnetic body.

Abstract: A method of controlling an electric machine, the method comprising storing a plurality of power maps, each power map comprising control values for driving the electric machine at different power, and selecting a power map in response to an input signal. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine.

Abstract: A method of controlling a brushless motor. The method includes measuring a temperature of the motor, adjusting a control value in the event that the measured temperature is lower than a threshold, and exciting a winding of the motor. The control value is then used to define an attribute of excitation, and the adjustment to the control value reduces the input power of the motor.

Abstract: A method of controlling a brushless permanent-magnet motor. The method includes commutating a winding of the motor at times relative to zero-crossings of back EMF in the winding. Commutation is then advanced when the motor operates over a first speed range, and commutation is retarded when the motor operates over a second speed range higher than that of the first speed range.

Abstract: A method of controlling a brushless permanent-magnet motor. The method includes dividing each half of an electrical cycle of the motor into a conduction period followed by a primary freewheel period. The conduction period is then divided into a first excitation period, a secondary freewheel period, and a second excitation period. The method then involves exciting a winding of the motor during each excitation period and freewheeling the winding during each freewheel period. The secondary freewheel period has a position and length within the conduction period that acts to reduce the harmonic content of current in the winding relative to back EMF in the winding. As a result, the efficiency of the motor is improved.

Abstract: A method of controlling a brushless permanent-magnet motor. The method includes commutating a winding of the motor at times that are retarded relative to zero-crossings of back EMF in the winding.

Abstract: A controller for a brushless motor that is configured to operate in normal mode or under-voltage mode. When operating in normal mode, the controller generates control signals for exciting a winding of the motor, monitors the magnitude of an input voltage, and switches to under-voltage mode in the event that the input voltage drops below an under-voltage threshold. When operating in under-voltage mode, the controller suspends excitation of the winding, monitors the magnitude of the input voltage, monitors the magnitude of a supply voltage used to power the controller, switches to normal mode in the event that the input voltage exceeds a restart threshold, and resets itself in the event that the supply voltage drops below a brown-out threshold.

Abstract: A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, exciting a winding of the motor with the rectified voltage for a conduction period over each electrical half-cycle of the motor, and updating the conduction period in response to a zero-crossing in the alternating voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

Abstract: A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, exciting a winding of the motor with the rectified voltage and freewheeling the winding when current in the winding exceeds a threshold. The winding is freewheeled for a freewheel period, which is updated in response to a zero-crossing in the alternating voltage. Additionally, a control system that implements the method, and a motor system that incorporates the control system.

Abstract: A controller for a brushless motor that is configured to operate in normal mode or under-voltage mode. When operating in normal mode, the controller generates control signals for exciting a winding of the motor, monitors the magnitude of an input voltage, and switches to under-voltage mode in the event that the input voltage drops below an under-voltage threshold. When operating in under-voltage mode, the controller suspends excitation of the winding, monitors the magnitude of the input voltage, monitors the magnitude of a supply voltage used to power the controller, switches to normal mode in the event that the input voltage exceeds a restart threshold, and resets itself in the event that the supply voltage drops below a brown-out threshold.

Abstract: A method of controlling a brushless permanent-magnet motor. The method includes dividing each half of an electrical cycle of the motor into a conduction period followed by a primary freewheel period. The conduction period is then divided into a first excitation period, a secondary freewheel period, and a second excitation period. The method then involves exciting a winding of the motor during each excitation period and freewheeling the winding during each freewheel period. The secondary freewheel period has a position and length within the conduction period that acts to reduce the harmonic content of current in the winding relative to back EMF in the winding. As a result, the efficiency of the motor is improved.

Abstract: A method of controlling a brushless motor. The method includes storing a power lookup table that comprises a control value for each of a plurality of voltages or speeds, measuring the magnitude of a supply voltage or the speed of the motor, and indexing the power lookup table using the measured voltage or speed to select a control value. The method further includes measuring a temperature of the motor and applying a compensation value to the selected control value in the event that the measured temperature exceeds a threshold. A winding of the motor is then excited with the supply voltage and the selected control value is used to define an attribute of excitation. The compensation value, when applied to the selected control value, causes a reduction in the input power of the motor.

Abstract: A method of controlling a brushless motor. The method includes measuring a temperature of the motor, adjusting a control value in the event that the measured temperature is lower than a threshold, and exciting a winding of the motor. The control value is then used to define an attribute of excitation, and the adjustment to the control value reduces the input power of the motor.

Abstract: A method of controlling a brushless permanent-magnet motor. The method includes commutating a winding of the motor at times that are retarded relative to zero-crossings of back EMF in the winding.