Motor controls, refrigeration systems and methods of motor operation and control
First Claim
1. A method of operating a brushless motor having a stationary assembly with at least two different energizable windings for producing spaced apart magnetic fields in time sequence, and a rotor adapted to rotate in response to the magnetic fields, the method comprising the steps of:
- simulating rotor position in accordance with the back emf condition of at least one winding;
selectively energizing the windings in accordance with the simulated rotor position;
sensing an underspeed condition when the motor speed is less than a minimum value for a length of time; and
preventing energization of any of the windings when the motor speed is less than the minimum value for the length of time.
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Accused Products
Abstract
A method of operating a brushless motor having a stationary assembly with at least two different energizable windings for producing spaced apart magnetic fields in time sequence, and a rotor adapted to rotate in response to the magnetic fields. The method includes the steps of simulating rotor position in accordance with the back emf condition of at least one winding, energizing a selected one of the windings in accordance with the simulated rotor position, sensing an underspeed condition when the motor speed is less than a minimum value for a length of time, and preventing energization of any of the windings when the motor speed is less than the minimum value for the length of time. An electrically commutated motor controller apparatus controls and speed of a variable speed motor compressor driven by an electrically commutated motor. A controller circuit includes a circuit for producing feedback signals representative of a back emf of the motor. A compressor speed circuit generates actual compressor speed signals for the feedback signals produced by the controller circuit. A duty cycle generator produces a speed controller signal as a function of the actual compressor speed signals, and the speed control signal is transmitted to the controller circuit for adjusting the speed of the electrically commutated motor driven compressor. Other motor controls, refrigeration systems and methods of control and operation are also disclosed.
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Citations
28 Claims
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1. A method of operating a brushless motor having a stationary assembly with at least two different energizable windings for producing spaced apart magnetic fields in time sequence, and a rotor adapted to rotate in response to the magnetic fields, the method comprising the steps of:
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simulating rotor position in accordance with the back emf condition of at least one winding; selectively energizing the windings in accordance with the simulated rotor position; sensing an underspeed condition when the motor speed is less than a minimum value for a length of time; and preventing energization of any of the windings when the motor speed is less than the minimum value for the length of time. - View Dependent Claims (2, 3, 4, 5)
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6. A method of operating a brushless motor having a stationary assembly with at least two windings energizable from a voltage source for producing spaced apart magnetic fields in time sequence, and a rotor adapted to rotate in response to the magnetic fields, the method comprising the steps of:
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simulating rotor position in accordance with the back emf condition of at least one winding; selectively energizing the windings from the voltage source in accordance with the simulated rotor position; sensing an undervoltage condition when the voltage source provides a voltage that is less than a minimum value; and preventing energization of any of the windings when the undervoltage condition is sensed. - View Dependent Claims (7, 8, 9, 10, 11)
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12. A method of operating a brushless motor having a stationary assembly with at least two windings and energizable from a voltage source for producing spaced apart magnetic fields in time sequence, and a rotor adapted to rotate in response to the magnetic fields, the method comprising the steps of:
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determining the back emf condition of at least one winding; simulating rotor position in accordance with the determining back emf condition of said at least one winding; selectively energizing the windings with a voltage from the voltage source in accordance with the simulated rotor position as defined by the determined back emf; sensing an overvoltage condition when the voltage is greater than a maximum value; and preventing energization of any of the windings when the overvoltage condition is sensed. - View Dependent Claims (13, 14, 15)
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16. A control system for a brushless motor for energization from a voltage source for the motor, the motor having a stator with windings and a rotor mounted for rotation relative to the stator, comprising:
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a circuit for generating an input signal corresponding to the presence of the rotor at one of a plurality of predetermined rotary positions with respect to the stator; electrically controllable switches connected to the windings to control the flow of current therethrough; an electronic control responsive to the input signal for controlling in a closed loop running mode the switches to commutate the windings of the motor after receipt of the input signal, said electronic control also being responsive to the speed of the motor, and operative to start the motor in a starting mode by controlling the switches to commutate the windings at an increasing rate, and then to shift commutation to the running mode once the motor reaches a predetermined speed, said electronic control being operative to determine the commutation rate as a function of the voltage applied to the motor. - View Dependent Claims (17, 18, 19)
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20. The method for controlling a brushless motor for energization from a source of voltage for the motor, the motor having a stator with windings and a rotor mounted for rotation relative to the stator, with electrically controllable switch means connected between the source and the windings to control the flow of current therethrough, the method comprising the steps of:
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determining an increasing rate of commutation as a function of the voltage applied to the motor; starting the motor in a starting mode by controlling the switch means to commutate the windings at the determined increasing rate; once a predetermined motor speed has been reached, shifting commutation from said starting mode to a running mode of operation; generating an input signal corresponding to the presence of the rotor at one of a plurality of predetermined rotary positions with respect to the stator; and controlling the switch means to commutate the windings of the motor after the input signal is generated. - View Dependent Claims (21, 22, 23)
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24. A control system for an electronically commutated motor adapted to be energized from a source of voltage and including a stationary assembly having a plurality of winding stages adapted to be electronically commutated in at least one preselected sequence, and a rotatable assembly associated in selective magnetic coupling relation with the winding stages, the control system comprising:
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an electronic commutation circuit including switches responsive to control signals and operable generally for electronic commutation of at least some of the winding stages of the electronically commutated motor by applying the voltage thereto in the at least one preselected sequence to effect the energization of the electronically commutated motor and the rotation of the rotatable assembly; and a circuit for generating control signals for said electronic commutation circuit, said circuit for generating variably establishing a time interval between commutations as a decreasing function of the voltage applied to the motor, for repeatedly producing in a start mode the control signals for said electronic commutation circuit at the interval variably established, and for shifting commutation to a running mode once the time interval decreases to a predetermined amount. - View Dependent Claims (25, 26)
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27. A method of operating a control system for an electronically commutated motor adapted to be energized from a source of voltage and including a stationary assembly having a plurality of winding stages adapted to be electronically commutated in at least one preselected sequence, and a rotatable assembly associated in selective magnetic coupling relation with the winding stages, the method comprising the steps of:
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electronically commutating at least some of the winding stages of the electronically commutated motor in response to control signals by applying the voltage thereto in the at least one preselected sequence to effect the energization of the electronically commutated motor and the rotation of the rotatable assembly; establishing a variable time interval between commutations as a decreasing function of the voltage applied to the motor; producing in a start mode the control signals with the variable time so established; and shifting commutation to another mode once the time interval decreases to a predetermined amount.
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28. A brushless motor system for energization from a voltage source, comprising a brushless electric motor having a stationary assembly with a plurality of windings adapted to be energized through electronic commutation in at least one preselected sequence, and a rotor in selective magnetic coupling relation with said windings;
- at least one circuit element that generates a position signal corresponding to the presence of said rotor in at least one predetermined rotary position with respect to said stationary assembly;
switches connected to said windings to control the flow of current therethrough; and
an electronic control responsive to said position signal for controlling said motor in a closed loop running mode with said switches to commutate said winding in response to said position signal, said electronic control also being responsive to the speed of said motor and operative to provide a starting mode to start Said motor by controlling said switches to commutate said windings at an increasing rate and shifting said commutation from said starting mode to said running mode when said motor reaches a predetermined speed, said electronic control being operative to determine the commutation rate as a function of the voltage applied to said motor.
- at least one circuit element that generates a position signal corresponding to the presence of said rotor in at least one predetermined rotary position with respect to said stationary assembly;
Specification