(12) Ulllted States Patent
`Marcinkiewicz et a].
`
`(10) Patent N0.:
`(45) Date of Patent:
`
`US 7,626,349 B2
`Dec. 1, 2009
`
`US007626349B2
`
`(54) LOW NOISE HEATING, VENTILATING
`AND/OR AIR CONDITIONING (HVAC)
`SYSTEMS
`
`(75) Inventors: Joseph G. Marcinkiewicz, St. Peters,
`MO (Us); Arthur E_ Woodard’
`Manchester M0
`Prakash B_
`Shahi, St. Louis, MO (US); Mark E.
`Carrier, WildWood, MO (US); Michael
`I‘ Henderson’ NOnhYOrkshlre (GB)
`.
`_
`.
`.
`(73) Asslgnee' Emerson Electnc Co" St' Lows’ MO
`(Us)
`
`( * ) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U'S'C~ 154(1)) by 300 days'
`
`(21) Appl. N0.: 11/701,350
`
`(22) Filed:
`
`Feb. 1, 2007
`
`(65)
`
`Prior Publication Data
`Us 2008/0185986 A1
`Au 7 2008
`g' ’
`
`(200601)
`318/400 02_ 318/400 32
`'
`’
`318/599’
`
`(51) Int CL
`H021; 21/00
`(52) U 5 Cl
`'
`'
`' """""""""""""" "
`_
`_
`_
`(58) Fleld of classgiligzzgngezgcoh3i"455's
`See a lication ?le for‘ co’m le'te gearcl’l hist’o
`pp
`p
`1y‘
`References Cited
`
`(56)
`
`’
`
`US. PATENT DOCUMENTS
`
`6/1995 Bausch ................ .. 318/400.04
`5,426,354 A *
`9/1995 Kelley et a1.
`318/40035
`5,448,141 A *
`5,969,498 A * 10/1999 Cooke ...................... .. 318/799
`6,326,750 B1
`12/2001 Marcinkiewicz
`6,756,757 B2
`6/2004 Marcinkiewicz et a1~
`7,208,895 B2
`4/2007 Marcinkiewicz et at
`2006/0290302 A1 12/2006 Marcinkiewicz et a1.
`
`OTHER PUBLICATIONS
`“Closed-Loop Vector Yorque Control,” WWW.Worldservo.com/html/
`features/vectorhtm; [retrieved on Nov. 22, 2006]; pp. 1-3.
`“Sinewave Commutation,” wwwworldservo.com/html/features/
`sine.htm; [retrieved on Nov. 22, 2006]; pp. 1-3.
`
`* cited by examiner
`_
`_
`_
`Primary ExamlneriRina I Duda
`(74) Attorney, Agent, or FirmiHarness, Dickey & Pierce,
`P-L-C
`
`(57)
`
`ABSTRACT
`
`A heating, ventilating and/or air conditioning (HVAC) system
`includes a system controller, a motor controller, an air-mov
`ing component, and a permanent magnet motor having a
`stationary assembly, a rotatable assembly in magnetic cou
`pling relation to the stationary assembly, and a shaft coupled
`to the air-moving component. The motor controller is con?g
`ured for performing sineWave commutation in response to
`one or more control signals received from the system control
`ler to produce continuous phase currents in the permanent
`magnet motor for driving the air-moving component. By
`using sineWave commutation (in contrast to square Wave
`commutation), the noise and vibration produced by the
`HVAC system is markedly reduced.
`
`5,410,230 A *
`
`4/1995 Bessler et a1. ............. .. 318/471
`
`20 Claims, 4 Drawing Sheets
`
`gig-rig:
`Choke F—“ Input Connector
`Earth DOUbE
`
`3-Q BPM Motor
`81 BlOWet' Load
`
`i
`1
`Fuse, MOV,
`r
`In Rush NTC,
`i
`.' EMI Filter (Z-stage)
`
`P
`
`Bridge
`Recti?er,
`Bus Caps
`
`l
`:
`l
`Logic 15 3-6 Inverter Module, :
`supply we V-buS. l-phase &
`.
`Temp Sense
`1
`
`I
`I
`
`I
`
`iPower PCB
`
`PC or
`Field
`App
`
`~ _ _ _ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ _|
`
`33 W‘ T
`
`F
`
`l
`I
`
`E
`I
`
`4 \Mre
`
`Serial
`Com
`
`1
`Processor PCB
`I
`1 Analog and Digital Control,
`41
`A,‘
`Application Interface
`:
`16 15 pin
`Ire PCB L _______ _ .1
`(Optional)
`
`

`
`US. Patent
`
`Dec. 1, 2009
`
`Sheet 1 0f 4
`
`US 7,626,349 B2
`
`. > - - h u - n a b u
`
`M21
`
`WJ
`
`Figure ‘
`
`(Prior Art)
`
`m I.‘
`I
`iii
`|
`I
`Ii al
`Jim
`Ml
`mm 1:1,,
`1
`iu'll
`“I
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`lililli
`mi
`iii!
`lhliliilihh
`N.
`\ mum
`li‘lili
`W
`H
`
`Figure 2
`(Prior Art)
`
`

`
`US. Patent
`
`Dec. 1, 2009
`
`Sheet 2 of4
`
`US 7,626,349 B2
`
`300
`Q
`
`Receiving at least one control signal / 302
`from a system controller
`
`Pcrfonning sinewavo commutation in response to the cone-oi signal
`to produce continuous phase currents in the permanent magnet motor
`for driving the air-moving component
`
`/ 304
`
`Figure 3
`
`3-6 BPM Motor
`8‘ Biower Load
`
`AC Line
`Source
`choke
`lnput Connector
`Earth DoubleL]
`--+ ------------------------------- -—
`l
`
`---
`
`lI
`
`l
`Fuse, MOV,
`I
`In Rush NTC,
`1
`: EMI Filter (Z-stage)
`l
`
`+-
`
`Bridge
`Recti?er,
`Bus Caps
`
`I
`Lo ic
`Su 9 l
`pp y
`
`i
`15 3-@ Inverter Module, |
`:
`V55
`V-bus, l-phase &
`Temp Sense
`:
`l
`
`i
`
`L Power PCB
`
`l _ " - - T " " _ ' - ' ' - _ ‘ ’ ' ' — ' ' ' - - - - “I
`
`l
`
`3-3 Vdc
`
`Serial
`Com
`
`Processor PCB
`Analog and Digital Control,
`Application Interface
`
`Figure 7
`
`

`
`US. Patent
`
`Dec. 1, 2009
`
`Sheet 3 of4
`
`US 7,626,349 B2
`
`401]
`
`System
`Coniroller
`
`/
`402
`
`Rotor
`
`Motor
`Commoner r-
`
`Stator
`
`mi
`
`4\n6
`
`Air-Moving
`Component
`\
`410
`
`\
`408
`
`Figure 4
`
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`
`0.05
`
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`
`Figure 5
`
`Figure 6
`
`

`
`U.S. Patent
`
`Dec. 1, 2009
`
`Sheet 4 of4
`
`US 7,626,349 B2
`
`.5593532
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`

`
`US 7,626,349 B2
`
`1
`LOW NOISE HEATING, VENTILATING
`AND/OR AIR CONDITIONING (HVAC)
`SYSTEMS
`
`2
`Further, knoWn square Wave commutation techniques are
`considered relatively ine?icient, and produce an e?iciency
`loss in the motor on the order of about tWo percent (2%).
`
`FIELD
`
`SUMMARY
`
`The present disclosure relates to heating, ventilating and/or
`air conditioning (HVAC) systems including HVAC systems
`employing one or more air-moving components such as a
`blower.
`
`BACKGROUND OF THE INVENTION
`
`The statements in this section merely provide background
`information related to the present disclosure and may not
`constitute prior art.
`Various types of climate control systems are knoWn in the
`art for providing heating, ventilating and/or air conditioning
`(HVAC). Many of these systems employ one or more air
`moving components, including bloWers (such as air handlers
`and circulation fans), condenser fans, draft inducers, etc.
`These air-moving components are commonly driven by elec
`tric motors. While single speed and multi-speed motors are
`sometimes used to drive air-moving components, discrete
`speed motors have largely been displaced in recent years by
`variable speed motors.
`Variable speed motors for driving air-moving components
`in HVAC systems commonly employ square Wave excitation
`and control techniques (sometimes referred to as “6-step”
`commutation). Typically, such variable speed motors use
`square Wave control signals to control the application of posi
`tive and negative do voltages to the motor’ s three phase Wind
`ings. At any given time, a positive dc voltage is applied to one
`of the phase Windings, a negative dc voltage is applied to
`another one of the phase Windings, and the third phase Wind
`ing is unenergiZed or “open” (the unenergiZed phase Winding
`is usually not truly left open, but rather “?ies” into a catch
`diode or other device for dissipating residual Winding cur
`rent). By sequentially (and abruptly) rotating the application
`of positive and negative dc voltages among the three phase
`Windings, a rotating magnetic ?eld is created Which causes
`rotation of the rotor for driving the air-moving component.
`FIG. 1 illustrates the phase currents produced in a motor
`using knoWn square Wave commutation techniques (the cur
`rent offsets are shifted in FIG. 1 to clearly illustrate all three
`phase currents). Because of the manner in Which the phase
`Windings are abruptly sWitched, With one phase Winding
`unenergiZed at any given time, the resulting phase currents
`are discontinuous. As can be seen in FIG. 1, each phase
`current has a Zero voltage level for about one-third of each
`cycle.
`The knoWn square Wave commutation techniques and
`resulting discontinuous phase currents produce relatively
`high cogging torque, as illustrated in FIG. 2, as Well as rela
`tively high operating torque ripple and torque harmonics.
`This, in turn, produces undesirable acoustic noise and vibra
`tion in the motor and thus any HVAC system in Which the
`motor is used. For these reasons, many knoWn HVAC motors
`couple the rotatable assembly (also referred to as the rotor) to
`the motor shaft using a mechanical damping material to
`reduce noise and vibration.
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`According to one example of the present disclosure, a
`heating, ventilating and/ or air conditioning (HVAC) system
`includes a system controller, a motor controller, an air-mov
`ing component, and a permanent magnet motor having a
`stationary assembly, a rotatable assembly in magnetic cou
`pling relation to the stationary assembly, and a shaft coupled
`to the air-moving component. The motor controller is con?g
`ured for performing sineWave commutation in response to
`one or more control signals received from the system control
`ler to produce continuous phase currents in the permanent
`magnet motor for driving the air-moving component.
`According to another example of the present disclosure, a
`method is provided for driving an air-moving component of a
`heating, ventilating and/ or air conditioning (HVAC) system
`in response to a control signal. The HVAC system includes a
`permanent magnet motor having a stationary assembly and a
`rotatable assembly in magnetic coupling relation to the sta
`tionary assembly. The rotatable assembly is coupled in driv
`ing relation to the air-moving component. The method
`includes receiving at least one control signal from a system
`controller, and performing sineWave commutation in
`response to the control signal received from the system con
`troller to produce continuous phase currents in the permanent
`magnet motor for driving the air-moving component.
`According to yet another example of the present disclo
`sure, a bloWer assembly for a heating, ventilating and/or air
`conditioning (HVAC) system includes a motor controller, a
`bloWer, and a permanent magnet motor having a stationary
`assembly, a rotatable assembly in magnetic coupling relation
`to the stationary assembly, and a shaft coupled to the bloWer.
`The motor controller is con?gured for performing sineWave
`commutation in response to one or more control signals
`received from a system controller to produce continuous
`phase currents in the permanent magnet motor for driving the
`bloWer.
`According to still another example of the present disclo
`sure, a motor and controller assembly for HVAC systems
`includes a motor controller con?gured for receiving one or
`more control signals from an HVAC system controller, and
`for performing sineWave commutation in response to the
`received control signal(s) to produce continuous phase cur
`rents in the permanent magnet motor for driving an air-mov
`ing component When the air-moving component is coupled in
`driving relation to the permanent magnet motor.
`Further areas of applicability Will become apparent from
`the description provided herein. It should be understood that
`the description and speci?c examples are intended for pur
`poses of illustration only and are not intended to limit the
`scope of the present disclosure.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`The draWings described herein are for illustration purposes
`only and are not intended to limit the scope of the present
`disclosure in any Way.
`FIG. 1 is a graph of discontinuous phase currents produced
`in a variable speed motor under square Wave commutation
`control according to the prior art.
`FIG. 2 is a graph illustrating the relatively high cogging
`torque of a prior art variable speed HVAC motor under square
`Wave commutation control.
`
`

`
`US 7,626,349 B2
`
`3
`FIG. 3 is a block diagram of a method for driving an
`air-moving component of an HVAC system according to one
`embodiment of the present disclosure.
`FIG. 4 is a block diagram of an HVAC system having a
`motor and motor controller for driving an air-moving com
`ponent according to another embodiment of the present dis
`closure.
`FIG. 5 is a graph of the continuous and substantially sinu
`soidal phase currents produced in the permanent magnet
`motor of FIG. 4 using sineWave commutation techniques.
`FIG. 6 is a graph illustrating the relatively loW cogging
`torque of the permanent magnet motor shoWn in FIG. 4 under
`sineWave commutation control.
`FIG. 7 is a block diagram of an HVAC bloWer assembly
`according to another embodiment of the present disclosure.
`FIG. 8 is a block diagram of a sensorless vector control
`scheme performed by the controller shoWn in FIG. 7.
`
`DETAILED DESCRIPTION
`
`The folloWing description is merely exemplary in nature
`and is not intended to limit the scope of the present disclosure
`nor its potential applications and uses.
`According to one aspect of the present disclosure, a method
`is provided for driving an air-moving component of a heating,
`ventilating and/or air conditioning (HVAC) system in
`response to a control signal. The HVAC system includes a
`permanent magnet motor having a stationary assembly (sta
`tor) and a rotatable assembly (rotor) in magnetic coupling
`relation to the stationary assembly. The rotatable assembly is
`coupled in driving relation to the air-moving component. As
`illustrated in FIG. 3, the method 300 includes receiving at
`least one control signal from a system controller (block 302),
`and performing sineWave commutation in response to the
`control signal received from the system controller to produce
`continuous phase currents in the permanent magnet motor for
`driving the air-moving component (block 304). Employing
`sineWave commutation in the HVAC system provides a num
`ber of advantages, including reducing the operating torque
`ripple of the permanent magnet motor, especially as com
`pared to prior art motors that employ square Wave commuta
`tion techniques. As a result, the acoustic noise produced by
`the HVAC system is likeWise reduced.
`One example of a system for practicing the method 300 of
`FIG. 3 Will noW be described With reference to FIG. 4. It
`should be understood, hoWever, that other systems may be
`employed for practicing the method of FIG. 3 Without depart
`ing from the scope of this disclosure.
`As shoWn in FIG. 4, the system 400 includes a system
`controller 402, a motor controller 404, a permanent magnet
`motor 406 and an air-moving component 410. The permanent
`magnet motor 406 includes a shaft 408, a stationary assembly
`412 and a rotatable assembly 414. The rotatable assembly 414
`is magnetically coupled to the stationary assembly 412. The
`rotatable assembly 414 is coupled to the air-moving compo
`nent, in this particular example via the shaft 408, for driving
`rotation of the air-moving component 410.
`The motor controller 404 is con?gured for performing
`sineWave commutation in response to one or more (analog or
`digital) control signals received from the system controller
`402 to produce continuous phase currents in the permanent
`magnet motor 406 for driving the air-moving component 410.
`As shoWn in FIG. 4, the motor controller 404 is coupled to the
`system controller 402 for receiving control signals directly
`from the system controller 402. Such control signals may
`represent, for example, a desired torque or speed of the motor
`
`20
`
`25
`
`30
`
`35
`
`40
`
`45
`
`50
`
`55
`
`60
`
`65
`
`4
`406. Alternatively, the control signals may represent a desired
`air?oW to be produced by the air-moving component 410.
`For the particular embodiment shoWn in FIG. 4, the motor
`controller 404 is con?gured for performing sineWave com
`mutation using vector control to ensure the continuous phase
`currents produced in the permanent magnet motor are sub
`stantially sinusoidal. As appreciated by those skilled in the
`art, using vector control techniques (Which involve transfor
`mation(s) to different frame(s) of reference) typically
`requires determining the rotor position. This can be accom
`plished using sensor(s) or sensorless techniques.
`In the case Where the air-moving component 410 is a
`bloWer and the motor controller 404 is con?gured to operate
`in a constant air?oW mode (also called a constant cubic feet
`per minute (CFM) mode, in Which the bloWer is controlled so
`as to provide a desired level of air?oW), a vector control
`architecture provides a substantially constant torque over the
`operating range of the permanent magnet motor. Therefore,
`the constant air?oW control laWs need not address torque
`changes that could otherWise occur With changes in the speed,
`etc. Moreover, due to the dynamic response of the vector
`control architecture, there is substantially no interaction With
`the constant air?oW control loop. Additional details regarding
`sensorless control techniques and sineWave commutation
`using vector control (as Well as speed, torque and constant
`air?oW control schemes, discussed beloW) are disclosed in
`Us. Pat. Nos. 6,326,750, 6,756,757, 7,208,895 and 7,342,
`379, the entire disclosures of Which are incorporated herein
`by reference.
`The air-moving component 410 can be a bloWer, such as an
`air handler or circulation fan, an indoor or outdoor condenser
`fan, a draft inducer fan, etc. It should be understood, hoWever,
`that other types of air-moving components can be coupled in
`driving relation to the rotatable assembly 414 Without depart
`ing from the scope of this disclosure. Further, the system
`controller 402 may be a thermostat, an additional control
`module in communication With a thermostat, or a standalone
`controller for the HVAC system 400.
`In the embodiment of FIG. 4, the permanent magnet motor
`406 is a variable speed brushless permanent magnet (BPM)
`motor, such as a back-electromagnetic ?eld (back-emf) BPM
`motor having a segmented stator. It should be understood,
`hoWever, that other types of permanent magnet motors (in
`cluding motors With embedded or surface magnets on the
`rotor or the stator, motors With segmented or non-segmented
`stators, and discrete speed(s) motors) can be employed With
`out departing from the scope of this disclosure.
`In the speci?c embodiment of FIG. 4, the stationary assem
`bly 412 includes three phase Windings (not shoWn) and the
`motor controller 404 is con?gured for energiZing all three of
`the phase Windings at the same time. FIG. 5 illustrates the
`continuous and substantially sinusoidal phase currents pro
`duced in the three phase Windings of the stationary assembly
`412 (the current offsets are shifted in FIG. 5 to clearly illus
`trate all three phase currents). The phase currents are continu
`ous because they each have substantially no period of Zero
`voltage. The phase currents illustrated in FIG. 5 are not per
`fectly sinusoidal due to, among other things, the presence of
`harmonics in the motor’s back emf. If desired, the motor
`controller 404 can be con?gured (using knoWn techniques) to
`produce continuous phase currents that cancel effects of har
`monic content in the permanent magnet motor’s back emf.
`Additional details regarding cancelling the effects of har
`monic content in the back emf are disclosed in the applica
`tions and patents referenced above.
`By using sineWave commutation in the motor controller
`404, the ef?ciency of the motor 406 (and thus the system 400)
`
`

`
`US 7,626,349 B2
`
`5
`is improved as compared to the square Wave commutation
`techniques employed in the prior art. Further, because of the
`continuous phase currents produced in the permanent magnet
`motor, the resulting operating torque is substantially free of
`torque ripple that could otherWise produce acoustic noise and
`vibration. As a result, in the particular embodiment shoWn in
`FIG. 4, the rotatable assembly 414 is coupled to the shaft 408
`Without using damping materials. Accordingly, the manufac
`turing cost of the permanent magnet motor 406 is reduced as
`compared to motors requiring damping materials to reduce
`acoustic noise. It should be understood, hoWever, that damp
`ing materials may still be employed, if desired, Without
`departing from the scope of this disclosure.
`Additionally, the motor 406 shoWn in FIG. 4 produces
`relatively little cogging torque, as shoWn in FIG. 6, particu
`larly as compared to the cogging torque shoWn in FIG. 2 for
`prior art motors under square Wave commutation control.
`This also helps reduce acoustic noise and vibration in the
`HVAC system 400.
`FIG. 7 illustrates a speci?c embodiment of the HVAC
`system of FIG. 4 in Which the air-moving component is a
`bloWer. In the embodiment of FIG. 7, the system controller is
`identi?ed as a “PC or Field” application. FIG. 8 provides a
`block diagram of the sensorless vector control performed by
`the processor printed circuit board (PCB) shoWn in FIG. 7.
`Those skilled in the art Will recogniZe that various changes
`can be made to the exemplary embodiments and implemen
`tations described above Without departing from the scope of
`the present disclosure. Accordingly, all matter contained in
`the above description or shoWn in the accompanying draW
`ings should be interpreted as illustrative and not in a limiting
`sense.
`What is claimed is:
`1. A heating, ventilating and/or air conditioning (HVAC)
`system comprising a system controller, a motor controller, an
`air-moving component, and a permanent magnet motor hav
`ing a stationary assembly, a rotatable assembly in magnetic
`coupling relation to the stationary assembly, and a shaft
`coupled to the air-moving component, Wherein the motor
`controller is con?gured for performing sineWave commuta
`tion, using independent values of Q and d axis currents, in
`response to one or more control signals received from the
`system controller to produce continuous phase currents in the
`permanent magnet motor for driving the air-moving compo
`nent.
`2. The HVAC system of claim 1 Wherein the stationary
`assembly includes a plurality of phase Windings and the
`motor controller is con?gured for energiZing all of the phase
`Windings at the same time.
`3. The HVAC system of claim 2 Wherein the continuous
`phase currents are substantially sinusoidal.
`4. The HVAC system of claim 3 Wherein the rotatable
`assembly is coupled to the shaft Without using a damping
`material.
`5. The HVAC system of claim 3 Wherein the air-moving
`component is a bloWer.
`6. The HVAC system of claim 3 Wherein the air-moving
`component is a draft inducer.
`7. The HVAC system of claim 3 Wherein the air-moving
`component is a condenser fan.
`8. The HVAC system of claim 3 Wherein the permanent
`magnet motor is a brushless permanent magnet (BPM) motor.
`
`40
`
`45
`
`20
`
`25
`
`30
`
`35
`
`50
`
`55
`
`60
`
`6
`9. The HVAC system of claim 8 Wherein the BPM motor is
`a back-emf BPM motor.
`10. The HVAC system of claim 3 Wherein the system
`controller includes a thermostat.
`11. The HVAC system of claim 3 Wherein the at least one
`control signal from the system controller represents a desired
`air?oW for the air-moving component.
`12. The HVAC system of claim 3 Wherein the at least one
`control signal from the system controller represents a desired
`torque or speed of the permanent magnet motor.
`13. The HVAC system of claim 3 Wherein the motor con
`troller is con?gured for performing sineWave commutation
`using vector control.
`14. The HVAC system of claim 13 Wherein the motor
`controller is con?gured for sensorlessly estimating a position
`of the rotatable assembly using a ?ux estimate produced
`using energiZation feedback from the permanent magnet
`motor.
`15. The HVAC system of claim 3 Wherein the motor con
`troller is con?gured to produce continuous phase currents that
`cancel effects of harmonic content in the permanent magnet
`motor’s back emf.
`16. A bloWer assembly for a heating, ventilating and/or air
`conditioning (HVAC) system, the bloWer assembly compris
`ing a motor controller, a bloWer, and a permanent magnet
`motor having a stationary assembly, a rotatable assembly in
`magnetic coupling relation to the stationary assembly, and a
`shaft coupled to the bloWer, Wherein the motor controller is
`con?gured for performing sineWave commutation, using
`independent values of Q and d axis currents, in response to
`one or more control signals received from a system controller
`to produce continuous phase currents in the permanent mag
`net motor for driving the bloWer.
`17. The bloWer assembly of claim 16 Wherein the motor
`controller is con?gured for sensorlessly estimating a position
`of the rotatable assembly using a ?ux estimate produced
`using energiZation feedback from the permanent magnet
`motor.
`18. The bloWer assembly of claim 17 Wherein the motor
`controller is con?gured to produce continuous substantially
`sinusoidal phase currents that cancel harmonic content in the
`permanent magnet motor’s back emf.
`19. A method for driving an air-moving component of a
`heating, ventilating and/ or air conditioning (HVAC) system
`in response to a control signal, the HVAC system including a
`permanent magnet motor having a stationary assembly and a
`rotatable assembly in magnetic coupling relation to the sta
`tionary assembly, said rotatable assembly coupled in driving
`relation to the air-moving component, the method comprising
`receiving at least one control signal from a system controller,
`and performing sineWave commutation, using independent
`values of Q and d axis currents, in response to the at least one
`control signal received from the system controller to produce
`continuous currents in the permanent magnet motor for driv
`ing said air-moving component.
`20. The method of claim 19 Wherein the air-moving com
`ponent is a bloWer, and Wherein receiving includes receiving
`at least one control signal representing a desired air?oW for
`the bloWer, a desired torque of the permanent magnet motor,
`or a desired speed of the permanent magnet motor.
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