Control system, electronically commutated motor system, blower apparatus and methods
First Claim
1. A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, and which control system is to be supplied with an externally derived first pulse width modulated series of pulses having a first duty cycle which is subject to sudden changes which would cause a substantial inrush current to the motor if used directly for control purposes, the control system comprising:
- means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly; and
means for applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly, whereby inrush current to the motor is substantially reduced when the first duty cycle changes suddenly.
2 Assignments
0 Petitions
Accused Products
Abstract
Control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly. The control system is adapted to be supplied with an externally derived first pulse width modulated series of pulses having a first duty cycle which is subject to sudden changes which would cause a substantial inrush current to the motor if used directly for control purposes. The control system includes circuitry for generating a second series of pulses and modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly. Further included is circuitry for applying a voltage to one or more of the winding stages at a tine in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly. In this way, inrush current to the motor is substantially reduced when the first duty cycle changes suddenly. Further control circuitry, electronically commutated motor systems, blower apparatus and methods are also disclosed.
147 Citations
57 Claims
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1. A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, and which control system is to be supplied with an externally derived first pulse width modulated series of pulses having a first duty cycle which is subject to sudden changes which would cause a substantial inrush current to the motor if used directly for control purposes, the control system comprising:
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means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly; and means for applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly, whereby inrush current to the motor is substantially reduced when the first duty cycle changes suddenly. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22)
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23. A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, and which control system is to be supplied with an externally derived first pulse width modulated series of pulses having a varying first duty cycle, the control system comprising:
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means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses; means for applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly; resettable means for counting the second series of pulses to produce a particular electrical output only when a predetermined number is reached and repeatedly resetting itself so that the predetermined number is not reached unless the first series of pulses becomes a substantially constant voltage that persists for a first time period during which the predetermined number of pulses in the second series of pulses occur; and means responsive to an occurrence of the particular electrical output for preventing the second pulse width modulated series of pulses from actuating said means for applying and commutating. - View Dependent Claims (24, 25, 26, 27, 28, 29)
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30. Blower apparatus for use with a heat exchanger to heat or cool a compartment, comprising:
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a fan for moving air over the heat exchanger to condition the air and thereby heat or cool the compartment by blowing conditioned air thereto; an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to said fan and adapted to rotate in response to the magnetic poles established by said winding stages; sensor means for sensing temperature within the compartment; level setting means for variably setting a desired level of temperature for the compartment; means connected to said sensor means and to said level setting means for deriving a first pulse width modulated series of pulses having a first duty cycle varying as a function of the the temperature and the desired level, which first duty cycle is subject to sudden changes which would cause a substantial inrush current to said motor if used directly for control purposes; means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly; and means for applying a voltage to one or more of said winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating said winding stages in a preselected sequence to rotate said rotar and said fan with a variable speed to blow conditioned air to the compartment at a rate related to the second duty cycle, whereby inrush current to said motor is substantially reduced when the first duty cycle changes suddenly. - View Dependent Claims (31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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42. A control system for an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, the control system comprising:
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means for deriving a first pulse width modulated series of pulses having a width-to-period ratio that is subject to high rates of change that could produce motor current transients if the pulses were used directly for control purposes; means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second width-to-period ratio limited in its rate-of-change to less than a predetermined value regardless of the rate of change of the width-to-period ratio of the first series of pulses; means for applying a voltage to the electric motor in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly, whereby motor current transients are substantially reduced when the width-to-period ratio of the first series of pulses undergoes a high rate of change; and means for preventing the second pulse width modulated series of pulses from actuating said means for applying and commutating when the first series of pulses becomes a substantially constant voltage, regardless of level, that persists for a predetermined period of time.
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43. An electronically commutated motor system comprising:
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an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly; means for deriving a first pulse width modulated series of pulses having a first duty cycle which is subject to sudden changes which would cause a substantial inrush current to said motor if used directly for control purposes; means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly than the first duty cycle varies when the first duty cycle changes suddenly; and means for applying a voltage to one or more of said winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating said winding stages in a preselected sequence to rotate said rotatable assembly, whereby inrush current to said motor is substantially reduced when the first duty cycle changes suddenly. - View Dependent Claims (44, 45, 46, 47, 48, 49, 50)
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51. An electronically commutated motor system comprising:
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an electronically commutated motor having a stationary assembly with a plurality of winding stages and a rotatable assembly; means for deriving a first pulse width modulated series of pulses having a varying first duty cycle; means for generating a second series of pulses and means for modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses; means for applying a voltage to one or more of said winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating said winding stages in a preselected sequence to rotate said rotatable assembly; resettable means for counting the second series of pulses to produce a particular electrical output only when a predetermined number is reached and repeatedly resetting itself so that the predetermined number is not reached unless the first series of pulses becomes a substantially constant voltage for a first time period during which the predetermined number of pulses in the second series of pulses occur; and means responsive to an occurrence of the particular electrical output for preventing the second pulse width modulated series of pulses from actuating said means for applying and commutating. - View Dependent Claims (52)
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53. A method of controlling an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, which method is for use with an externally derived first pulse width modulated series of pulses having a first duty cycle which is subject to sudden changes which would cause a substantial inrush current to the motor if used directly for control purposes, the method comprising the steps of:
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generating a second series of pulses and modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly; and applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly, whereby inrush current to the motor is substantially reduced when the first duty cycle changes suddenly.
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54. A method of controlling an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, which method is for use with an externally derived first pulse width modulated series of pulses having a varying first duty cycle, the method comprising the steps of:
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generating a second series of pulses and modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses; counting the second series of pulses to produce a particular electrical output only when the first series of pulses becomes a substantially constant voltage that persists for an entire time period during which a predetermined number of pulses in the second series of pulses are counted; applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly; and discontinuing the applying step when the particular electrical output occurs.
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55. A method of controlling an electronically commutated motor having a stationary assembly with a plurality of winding stages and further having a rotatable assembly, which method is for use with an externally derived first pulse width modulated series of pulses having a width-to-period ratio that is subject to high rates of change that could produce motor current transients if the pulses were used directly for control purposes, the method comprising the steps of:
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generating a second series of pulses and modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second width-to-period ratio limited in its rate-of-change to less than a predetermined value regardless of the rate of change of the width-to-period ratio of the first series of pulses; applying a voltage to the electric motor in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotatable assembly, whereby motor current transients are substantially reduced when the width-to-period ratio of the first series of pulses undergoes a high rate of change; and terminating the applying step when the first series of pulses becomes a substantially constant voltage, regardless of level, that persists for a predetermined period of time. - View Dependent Claims (56)
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57. A method for operating a blower system having a fan for moving air over a heat exchanger to heat or cool a compartment, and an electronically commutated motor including a stationary armature having a core and at least two energizable winding stages arranged to establish a predetermined number of magnetic poles, and a permanent magnet rotor coupled to the fan and adapted to rotate in response to the magnetic poles established by the winding stages, the method comprising the steps of:
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sensing temperature within the compartment; variably setting a desired level of temperature for the compartment; deriving a first pulse width modulated series of pulses having a first duty cycle varying as a function of the temperature and the desired level, which first duty cycle is subject to sudden changes which would cause a substantial inrush current to the motor if used directly for control purposes; generating a second series of pulses and modulating their width in response to the first series of pulses to produce a second pulse width modulated series of pulses that has a second duty cycle which varies less rapidly over time than the first duty cycle varies when the first duty cycle changes suddenly; and applying a voltage to one or more of the winding stages at a time in accordance with the second pulse width modulated series of pulses and commutating the winding stages in a preselected sequence to rotate the rotor and the fan with a variable speed to blow conditioned air to the compartment at a rate related to the second duty cycle, whereby inrush current to the motor is substantially reduced when the first duty cycle changes suddenly.
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Specification