Patent application number | Description | Published |
20100225207 | ELECTRIC MACHINE - An electric machine that includes a stator and a Hall-effect sensor. The stator includes a pair of asymmetric poles and the sensor is oriented such that the plane of the sensor is substantially parallel to armature field lines passing through the sensor. | 09-09-2010 |
20100225208 | HOLDER FOR A POSITION SENSOR - A holder for a position sensor of an electric machine. The holder includes a pocket for holding the position sensor, an abutment, and a biasing mechanism mountable to a fixture of the electric machine so as to bias the abutment relative to the fixture. Additionally, an electric machine that incorporates the holder, the electric machine including a stator against which the biasing mechanism biases the abutment. | 09-09-2010 |
20100251511 | CONTROL OF A PERMANENT-MAGNET MOTOR - A method of controlling a permanent-magnet motor that includes sequentially exciting and freewheeling a winding of the motor. The method includes varying the angle over which the winding is freewheeled in response to changes in speed of the motor. Additionally, a control system for a permanent-magnet motor, and a product incorporating the control system and motor. | 10-07-2010 |
20100253264 | CONTROL OF AN ELECTRIC MACHINE - A method of controlling an electric machine that includes sequentially exciting and freewheeling a winding of the electric machine. The winding is excited in advance of zero-crossings of back emf in the winding by an advance angle, and the winding is freewheeled over a freewheel angle. The method then includes varying the advance angle and the freewheel angle in response to changes in the speed of the electric machine. Additionally, a control system for an electric machine, and a product incorporating the control system and electric machine. | 10-07-2010 |
20110254480 | CONTROL OF A BRUSHLESS MOTOR - 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. | 10-20-2011 |
20110254481 | CONTROL OF A BRUSHLESS MOTOR - 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. | 10-20-2011 |
20110254483 | CONTROL OF A BRUSHLESS MOTOR - A method of controlling a brushless motor that includes rectifying an alternating voltage to provide a rectified voltage, and exciting a winding of the motor with the rectified voltage. The winding is excited in advance of predetermined rotor positions by an advance period that 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. | 10-20-2011 |
20120081046 | CONTROL OF AN ELECTRICAL MACHINE - A method of controlling an electrical machine that includes selecting an edge of a rotor-position signal as a reference edge and commutating a phase winding of the electrical machine at times relative to the reference edge. The rotor-position signal has at least four edges per mechanical cycle, each of the edges being associated with a respective zero-crossing in back EMF or minimum in inductance of the phase winding. The angular position of at least one of the edges relative to its respective zero-crossing or minimum is different to that of the other edges. The reference edge is then selected from the edges such that the angular position of the reference edge relative to its respective zero-crossing or minimum is the same with each power on of the electrical machine. Additionally, a controller and control system that implement the method. | 04-05-2012 |
20120081064 | CONTROL OF AN ELECTRICAL MACHINE - A method of controlling an electrical machine that includes exciting a phase winding with a supply voltage, and freewheeling the phase winding when current in the phase winding exceeds a threshold. The threshold is then adjusted in response to changes in the supply voltage and/or the speed of the electrical machine. Additionally, a control system that implements the method and an electrical machine comprising the control system are described. | 04-05-2012 |
20130093374 | METHOD OF STARTING A BRUSHLESS MOTOR - A method of starting a brushless motor that includes a rotor, a stator having at least one phase winding, and a rotor-position sensor. The method involves exciting the winding and sensing a signal output by the sensor. If an edge of the signal is sensed during a first period, the winding is commutated in response to the edge. Otherwise, the method involves commutating the winding at the end of the first period, sensing the signal, and commutating the winding in response to a second of two edges of the signal sensed during a second period. Additionally, a control system that implements the method, and a motor assembly that incorporates the brushless motor and the control system. | 04-18-2013 |
20130127384 | METHOD OF CONTROLLING A BRUSHLESS MOTOR - A method of controlling a brushless motor that includes storing a lookup table of control values, periodically obtaining a speed-adjusted control value, and exciting a phase winding of the motor. The speed-adjusted control value is then used to define the phase and/or length of excitation. Obtaining the speed-adjusted control value includes measuring the speed of the motor, increasing or decreasing a speed-adjust variable in the event that the measured speed is greater or less than a threshold, selecting a control value from the lookup table using the measured speed, and adjusting the selected control value using the speed-adjust variable to obtain the speed-adjusted control value. Additionally, a control system that implements the method, and a motor assembly that incorporates the brushless motor and the control system. | 05-23-2013 |