NZ760787B2 - Switched reluctance motor - Google Patents
Switched reluctance motor Download PDFInfo
- Publication number
- NZ760787B2 NZ760787B2 NZ760787A NZ76078715A NZ760787B2 NZ 760787 B2 NZ760787 B2 NZ 760787B2 NZ 760787 A NZ760787 A NZ 760787A NZ 76078715 A NZ76078715 A NZ 76078715A NZ 760787 B2 NZ760787 B2 NZ 760787B2
- Authority
- NZ
- New Zealand
- Prior art keywords
- stator
- phase
- switched reluctance
- reluctance motor
- rotor
- Prior art date
Links
- 238000004804 winding Methods 0.000 claims abstract description 59
- 238000002560 therapeutic procedure Methods 0.000 claims description 45
- 238000009826 distribution Methods 0.000 claims description 18
- 206010038683 Respiratory disease Diseases 0.000 claims description 5
- 230000001276 controlling effect Effects 0.000 abstract description 9
- 238000005516 engineering process Methods 0.000 description 116
- 230000000241 respiratory Effects 0.000 description 34
- 238000004422 calculation algorithm Methods 0.000 description 27
- 238000004891 communication Methods 0.000 description 20
- 239000007789 gas Substances 0.000 description 19
- 230000029058 respiratory gaseous exchange Effects 0.000 description 17
- 208000008784 Apnea Diseases 0.000 description 16
- 230000004907 flux Effects 0.000 description 16
- 238000009423 ventilation Methods 0.000 description 16
- 206010002974 Apnoea Diseases 0.000 description 15
- 206010021079 Hypopnoea Diseases 0.000 description 15
- 230000003434 inspiratory Effects 0.000 description 10
- 239000000463 material Substances 0.000 description 10
- 206010041235 Snoring Diseases 0.000 description 9
- 229910052760 oxygen Inorganic materials 0.000 description 9
- 239000001301 oxygen Substances 0.000 description 8
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 238000011144 upstream manufacturing Methods 0.000 description 7
- 229910000976 Electrical steel Inorganic materials 0.000 description 5
- 206010067775 Upper airway obstruction Diseases 0.000 description 5
- 238000001514 detection method Methods 0.000 description 5
- 239000000789 fastener Substances 0.000 description 4
- 230000036961 partial Effects 0.000 description 4
- 238000007781 pre-processing Methods 0.000 description 4
- -1 samarium-cobalt Chemical compound 0.000 description 4
- 230000000153 supplemental Effects 0.000 description 4
- CURLTUGMZLYLDI-UHFFFAOYSA-N carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 230000000875 corresponding Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 3
- 230000005291 magnetic Effects 0.000 description 3
- 230000000414 obstructive Effects 0.000 description 3
- 230000000007 visual effect Effects 0.000 description 3
- 229910000531 Co alloy Inorganic materials 0.000 description 2
- 241001191345 Osa Species 0.000 description 2
- 230000001269 cardiogenic Effects 0.000 description 2
- 230000003247 decreasing Effects 0.000 description 2
- 239000003302 ferromagnetic material Substances 0.000 description 2
- 239000012530 fluid Substances 0.000 description 2
- 238000005304 joining Methods 0.000 description 2
- 229910000529 magnetic ferrite Inorganic materials 0.000 description 2
- 238000004377 microelectronic Methods 0.000 description 2
- 229910052761 rare earth metal Inorganic materials 0.000 description 2
- 150000002910 rare earth metals Chemical class 0.000 description 2
- 230000035812 respiration Effects 0.000 description 2
- 210000002345 respiratory system Anatomy 0.000 description 2
- 230000004044 response Effects 0.000 description 2
- 238000003860 storage Methods 0.000 description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 2
- 208000003417 Central Sleep Apnea Diseases 0.000 description 1
- 230000005355 Hall effect Effects 0.000 description 1
- 210000004072 Lung Anatomy 0.000 description 1
- 208000001797 Obstructive Sleep Apnea Diseases 0.000 description 1
- 210000000614 Ribs Anatomy 0.000 description 1
- 229910000831 Steel Inorganic materials 0.000 description 1
- 241000287181 Sturnus vulgaris Species 0.000 description 1
- 230000001070 adhesive Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 238000004220 aggregation Methods 0.000 description 1
- 230000002776 aggregation Effects 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 230000000844 anti-bacterial Effects 0.000 description 1
- 230000037007 arousal Effects 0.000 description 1
- 230000000712 assembly Effects 0.000 description 1
- 230000006399 behavior Effects 0.000 description 1
- 238000004590 computer program Methods 0.000 description 1
- 230000001809 detectable Effects 0.000 description 1
- 201000010099 disease Diseases 0.000 description 1
- 239000003814 drug Substances 0.000 description 1
- 229940079593 drugs Drugs 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000000977 initiatory Effects 0.000 description 1
- 238000003475 lamination Methods 0.000 description 1
- 230000000670 limiting Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 239000010807 litter Substances 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000006011 modification reaction Methods 0.000 description 1
- 229910001172 neodymium magnet Inorganic materials 0.000 description 1
- 230000003287 optical Effects 0.000 description 1
- 238000002640 oxygen therapy Methods 0.000 description 1
- 230000002829 reduced Effects 0.000 description 1
- 229910000938 samarium–cobalt magnet Inorganic materials 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000002269 spontaneous Effects 0.000 description 1
- 230000003068 static Effects 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Abstract
poly-phase switched reluctance motor assembly may include a stator assembly having a plurality of stator teeth, and with multiple coils in a distributed winding configuration, and a rotor assembly having a plurality of rotor poles. The plurality of rotor poles each having a width that is a sum of a width of each stator tooth of the plurality of stator teeth and each width of gaps adjacent to the stator tooth. A method of controlling a switched reluctance motor may include at least three phases wherein during each conduction period a first phase is energized with negative direction current, a second phase is energized with positive current and there is at least one non-energized phase. During each commutation period either the first phase or second phase switches off to a non-energized state and one of the non-energized phases switches on to an energized state with the same direction current as the first or second phase that was switched off. The switched reluctance motor may include a distributed winding configuration. a width of each stator tooth of the plurality of stator teeth and each width of gaps adjacent to the stator tooth. A method of controlling a switched reluctance motor may include at least three phases wherein during each conduction period a first phase is energized with negative direction current, a second phase is energized with positive current and there is at least one non-energized phase. During each commutation period either the first phase or second phase switches off to a non-energized state and one of the non-energized phases switches on to an energized state with the same direction current as the first or second phase that was switched off. The switched reluctance motor may include a distributed winding configuration.
Description
(12) Granted patent specificaon (19) NZ (11) 760787 (13) B2
(47) Publicaon date: 2021.12.24
(54) SWITCHED RELUCTANCE MOTOR
(51) Internaonal Patent Classificaon(s):
H02K 1/26 H02K 3/26 H02K 3/46
(22) Filing date: (73) Owner(s):
2015.01.16 RESMED MOTOR TECHNOLOGIES INC
(23) Complete specificaon filing date: (74) Contact:
2015.01.16 JAMES & WELLS
(62) Divided out of 721047 (72) Inventor(s):
MOIR, Michael Bruce
(30) Internaonal Priority Data: FLEMING, David James
US 61/928,547 2014.01.17 SADEGHI, Siavash
NAGORNY Aleksandr S
(57) Abstract:
A poly-phase switched reluctance motor assembly may include a stator assembly having a plurality
of stator teeth, and with mulple coils in a distributed winding configuraon, and a rotor assembly
having a plurality of rotor poles. The plurality of rotor poles each having a width that is a sum of
a width of each stator tooth of the plurality of stator teeth and each width of gaps adjacent to
the stator tooth. A method of controlling a switched reluctance motor may include at least three
phases wherein during each conducon period a first phase is energized with negave direcon
current, a second phase is energized with posive current and there is at least one non-energized
phase. During each commutaon period either the first phase or second phase switches off to
a non-energized state and one of the non-energized phases switches on to an energized state
with the same direcon current as the first or second phase that was switched off. The switched
reluctance motor may include a distributed winding configuraon.
NZ 760787 B2
SWITCHED RELUCTANCE MOTOR
1 CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of the filing date of U.S. Provisional Patent
Application No. 61/928,547 filed on January 17, 2014, the disclosure of which is hereby
incorporated herein by reference.
2 STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR
DEVELOPMENT
Not Applicable
3 THE NAMES OF PARTIES TO A JOINT RESEARCH DEVELOPMENT
Not Applicable
4 SEQUENCE LISTING
Not Applicable
BACKGROUND OF THE INVENTION
.1 FIELD OF THE INVENTION
The present technology relates to electronically commutated motors, particularly
switched reluctance motors, and the use thereof. These types of electronically commutated motors
produce continuous rotational torque without the use of permanent magnets. The present
technology further relates to switched reluctance motors having a small size and low noise output.
In some aspects the motors may be used in medical devices or apparatus configured to treat, prevent
and/or ameliorate respiratory-related disorders.
.2 DESCRIPTION OF THE RELATED ART
.2.1 Electronically Commutated Motors
One of the subgroups of electronically commutated motors are brushless D.C. motors.
Brushless D.C. motors are well known and used in a range of devices. Brushless D.C. motors
typically include permanent magnets coupled to or on a rotor and windings formed on a laminated
stator that form electromagnets when current is applied to the stator. High energy permanent
magnets used in motors may be made from materials which include rare earth metals such as
samarium-cobalt and neodymium-iron-boron. However, such permanent magnets are expensive
resulting in a higher cost motor. Furthermore the availability of these rare earth metals is limited.
To reduce costs other forms of brushless D.C. motors that do not require permanent magnets or
windings associated with the rotor were developed.
Another class of electronically commutated motors that do not include permanent
magnets are called switched reluctance (SR) motors. Switched reluctance motors run by creating
reluctance torque, which is proportional to the difference of aligned and non-aligned values of the
self-inductance in the SR motor. Conventional SR motors comprise concentrated windings in the
stator that produce torque due to the self-inductance variation slope of one phase and the positive
DC current applied to that phase. The inductance ratio between the aligned inductance and the
unaligned inductance is important in generating torque and may vary in the range of 3-8.
Consequently SR motors are used for the applications where the input power level exceeds several
hundred watts and are generally larger motors with stator outer diameters greater than 50 mm.
Such prior art SR motors have been used to drive devices such as automotives, vacuum cleaners
and washing machines and other large applications. They have not been suitable for driving low
power (less than a hundred watts) or small (stator outer diameters less than 50 mm) high speed
devices (up to 60,000 rpm) due to the failure to produce enough torque in a small arrangement
having low inductance ratios. SR motors have also been used in conditions where severe
environmental conditions occur such as in high or low temperatures.
The stators of SR motors are generally wound with three, four or five phases in a
concentrated winding arrangement. Typically a SR motor has less rotor poles than stator poles.
Figure 1 shows an example of a three phase SR motor stator and rotor arrangement. The three
phases are made up of three groups of concentrated windings: 10a, 10b, 10c, and 10d form a first
phase; 12a, 12b, 12c and 12d form a second phase; and 14a, 14b, 14c and 14d form the third phase.
In such a concentrated arrangement a coil with sides 10a and 10b, is wound around a stator tooth
or pole 22 of the stator 20, thus the windings are concentrated around one stator tooth 22. The rotor
is formed of a soft magnetic material, for example laminated silicon steel, and includes salient
magnetic poles 32 to create a difference in magnetic reluctance between rotor and stator along the
poles and between the poles.
Generally SR motors have been driven by applying current to energize a single stator
phase at one time and switching the current between stator phases to cause rotation of the rotor. A
flux is generated through the energized stator poles and the rotor poles, which pulls the rotor poles
towards and into alignment with the energized stator poles. Switching the current to a second
adjacent stator phase results in the pulling of the rotor poles to align with the second stator phase.
The continuous switching of the current in a sequence to adjacent stator phases around the stator
results in rotation of the rotor. Controlling the timing of the current switching controls the
continuity of the rotor rotation. Switching the current at the optimum position of the rotor is desired
to reduce torque ripple or cogging as the rotor rotates. Torque ripple may result in vibration and
noise within the motor. In attempts to reduce torque ripple the current being applied to adjacent
phases during the switching step has been overlapped. However, when current is applied to two
phases of a conventional SR motor in synchronism the motor is less efficient, as there is no
significant increase in torque despite twice the power input being provided.
In such SR motors one rotor pole is generally configured to align with a single stator
pole when the rotor is pulled into alignment with the energized stator pole. For example as seen
in Fig. 1, when stator phase 10, including stator coil sides 10a & 10b and 10c & 10d have been
energized the rotor poles, 32b and 32c are pulled to align with stator teeth 1 and 4 respectively.
Consequently the normal or radial components of the electromagnetic forces are applied to stator
teeth and rotor poles. Such radial forces may be relatively high and can be a source of vibration
and noise within the motor.
Some efforts have been made to reduce the motor noise produced by SR motors. For
example U.S. Patent No. 5,239,217 describes a multiple phase SR motor comprising a stator with
concentrated windings and multiple rotor poles. Each of the stator poles and the rotor poles may
comprise multiple teeth. The stator includes at least one redundant pole set for each motor phase
to help distribute ovalising forces on the motor assembly as it rotates and reduce motor noise.
U.S. Patent No. 6,028,385 suggests reducing the torque ripple effect by using rotor poles having 2
wide rotor poles and 2 narrow rotor poles. The three phase reluctance motor has concentrated
windings and includes 12 stator poles with the 4 rotor poles. During each energization phase, where
one phase is energized at a time the rotor is sequentially advanced such that the leading edge of a
wide rotor pole interacts with a first energized stator pole and then a narrow rotor pole is drawn
into alignment with a second energized stator pole of the same phase. However, to enable
significant torque to be produced from such arrangements these SR motors would be required to
be relatively large to maintain an inductance ratio of approximately 7 with the increased number
of stator poles.
U.S. Patent No. 5,111,095 is said to provide a SR motor producing increased torque
and efficiency. The SR motor comprises a stator having evenly spaced concentrated winding poles
and a rotor with unevenly spaced rotor poles. Two adjacent phases are energized at all times in
order to provide controlled rotation of the rotor. The adjacent windings are coiled in a direction
about the poles of the stator in a manner that causes the polarity of the stator poles to have opposite
polarities when the pair is energized with a current so as to create a magnetic circuit between the
poles of each pair. The pairs of adjacent stator poles align with half (e.g. 4) of the rotor poles and
when the next pair of adjacent stator poles are energized these align with the other half (e.g. further
4) of the rotor poles. Such a SR motor arrangement would not be suitable for use in high speed
small devices.
Chinese Patent Publication no. CN 102035333A is said to describe a permanent magnet
switched reluctance motor adopting a distributed winding. The stator adopts a three-phase
armature winding with a distributed structure, only one winding coil is arranged between adjacent
stator tooth slot bodies, coils which pass over two stator slots are connected together to form a
winding of one phase. A permanent magnet is also embedded into the stator. The ratio of the
number of the stator teeth to the number of the rotor teeth is 6:4, and the number of their poles is
in the form of 6/4 or 12/8.
There is further need to reduce one or more of the noise, vibration and/or size of SR
motors if they are to be used in medical devices and/or conditions where low noise is important,
such as during sleep.
.2.2 Motor Applications
Motors are used to drive a variety of devices in a diverse range of applications
including but not limited to fans, pumps, medical devices, automotive industry, aerospace, toys,
power tools, disk drives, and household appliances. Motors have been used in medical devices to
generate a supply of pressurized gas for example in Positive Airway Pressure (PAP) devices and
ventilators. These devices generally include permanent magnet brushless D.C. motors. SR motors
generally have not been used in such devices due to the generally larger size and higher level of
noise of SR motors.
The noise produced by some medical devices is required to be relatively low so as not
to disturb the user. In particular for medical devices that may be used for long periods of time,
such as throughout the day, and/or during sleep, such as PAP devices and/or ventilators the level
of noise emitted is a significant issue. Sound pressure values of a variety of objects are listed below:
Object A-weighted sound pressure dB(A) Notes
Vacuum cleaner: Nilfisk 68 ISO3744 at 1m
Walter Broadly Litter Hog: B+ distance
Grade
Conversational speech 60 1m distance
Average home 50
Quiet library 40
Quiet bedroom at night 30
ResMed S9 AutoSet™ PAP 26.5
device
Background in TV studio 20
6 BRIEF SUMMARY OF THE TECHNOLOGY
The present technology is directed towards switched reluctance motors and devices
that comprise such switched reluctance motors.
A first aspect of the present technology relates to switched reluctance motor
comprising a stator having a distributed winding configuration.
Another aspect of the present technology relates to switched reluctance motor having
higher total torque and distributed force.
Another aspect of the present technology relates to switched reluctance motor having
reduced radial forces and noise output.
Another aspect of the present technology relates to a switched reluctance motor with a
stator having an inductance ratio of less than 3. For example, technology relates to a switched
reluctance motor with a stator having an aligned-to-unaligned inductance ratio of less than 3.
One form of the present technology comprises a polyphase switched reluctance motor
assembly comprising a stator assembly including a plurality of coils and a stator with a central
bore, and a rotor assembly having a plurality of poles. The rotor assembly is arranged within the
central bore of the stator assembly and configured to rotate therein and the plurality of coils is
configured in a distributed winding configuration.
Furthermore, the stator of the poly-phase switched reluctance motor assembly may
include a plurality of projecting stator teeth forming a plurality of stator slots therebetween. Each
of the plurality of stator slots may comprise one of the plurality of coils. The total number of stator
slots may be determined as a function of a number of phases and a number of rotor poles of the
motor. The determination of the total number of stator slots may further include a winding
distribution parameter.
In some aspects the plurality of coils may include a coil group for each phase of the
poly-phase switched reluctance motor and each of the coils for each coil group are uniformly
distributed between the stator slots. Each coil group comprises at least one coil.
In some aspects the poly-phase switched reluctance motor assembly may include at
least three motor phases and in use two motor phases are energized at one time during a conduction
period. Furthermore one of the two energized phases is provided with a positive direction current
and the second of the two energized phases is provided with a negative direction current.
Additionally one of the two energized phases may be switched off to a non-energized state and one
of the non-energized phases may be switched on to an energized state during each commutation
period.
Some aspects of the present technology include a poly-phase switched reluctance
motor assembly wherein in use each phase of the motor is energized with the same current value
during at least two consecutive conduction periods.
One form of the present technology comprises a polyphase switched reluctance motor
assembly including a stator having an outer diameter less than 50 mm.
Another aspect of one form of the present technology is a stator for a poly-phase
switched reluctance motor comprising a plurality of stator teeth separated by stator slots and
surrounding a central bore and a plurality of coils that are configured in a distributed winding
configuration. The plurality of coils may include a coil group for each phase of the poly-phased
switched reluctance motor and the coil group may include one or more coils. The central bore of
the stator assembly is configured to receive a rotor assembly having a plurality of poles.
Furthermore each of the stator slots may comprise one of the plurality of coils.
Another aspect of one form of the present technology is a stator for a poly-phase
switched reluctance motor having an inductance ratio of less than 3.
Another aspect of one form of the present technology is a stator for a poly-phase
switched reluctance motor having an outer diameter of less than 50 mm.
Another aspect of one form of the present technology is a positive airway pressure
device comprising a poly-phase switched reluctance motor including a stator having a distributed
winding configuration. The positive airway pressure device configured to provide a supply of
pressurized breathable gas.
Another aspect of one form of the present technology is a system for treating a
respiratory disorder comprising a therapy device configured to provide a supply of pressurized
breathable gas, the therapy device comprising a poly-phase switched reluctance motor including a
stator having a distributed winding configuration. The system may further include an air delivery
conduit and a patient interface configured to receive the supply of pressurized gas from the therapy
device via the air delivery conduit and deliver the supply of pressurized gas to a patient. The
system may additionally include a humidifier configured to humidify the supply of pressurized
gas.
An aspect of one form of the present technology is a method of controlling a switched
reluctance motor comprising at least three phases. The method comprising during each conduction
period energizing a first phase with a negative direction current, energizing a second phase with a
positive current and having at least one non-energized phase and during each commutation period
switching off one of the first phase or the second phase to a non-energized state and switching on
one of the non-energized phases to an energized state with the same direction current as the first
or second phase that was switched off. Furthermore the switched reluctance motor may include a
distributed winding configuration.
Embodiments of the switched reluctance motor may be implemented without the use
of permanent magnets for rotation of the rotor or such as having no permanent magnets within the
stator.
Of course, portions of the aspects may form sub-aspects of the present technology.
Also, various ones of the sub-aspects and/or aspects may be combined in various manners and also
constitute additional aspects or sub-aspects of the present technology.
Although described in relation to medical devices the SR motors of the present
technology may be used in a range of applications.
Other features of the technology will be apparent from consideration of the information
contained in the following detailed description, abstract, drawings and claims.
7 BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
The present technology is illustrated by way of example, and not by way of limitation,
in the figures of the accompanying drawings, in which like reference numerals refer to similar
elements including:
7.1 MOTOR
Fig.1 shows an example of a prior art switched reluctance motor 6/4 stator and rotor
configuration with concentrated windings.
Fig. 2A shows an exemplary switched reluctance motor 6/2 stator and rotor
configuration with distributed windings in accordance with another aspect of the present
technology.
Fig. 2B shows an exemplary switched reluctance motor 12/4 stator and rotor
configuration with distributed windings in accordance with one aspect of the present technology.
Fig. 2C illustrates the winding configuration of the exemplary SR motor shown in Fig.
Fig. 2D illustrates the self and mutual inductances versus the mechanical angle of the
rotor of the exemplary SR motor of Fig. 2B.
Fig. 2E illustrates an exemplary pattern of applying current to the different phases of
the SR motors of Fig. 2B.
Fig. 2F illustrates the torque produced by the exemplary SR motor in Fig. 2B for
different current sequences.
Figs. 2G illustrates exemplary flux paths for a rotor mechanical angle of 0°, 180° and
360° as the minimum mutual inductance position when phase A is provided with positive current
and phase C is provided with negative current for the SR motor of Fig. 2B.
Figs. 2H illustrates exemplary flux paths for a rotor mechanical angle of 15° and 195°
as the maximum mutual inductance position when phase A is provided with positive current and
phase B is provided with negative current for the SR motor of Fig. 2B.
Figs. 2I illustrates exemplary flux paths for a rotor mechanical angle of 30° and 210°
as the minimum mutual inductance position when phase B is provided with positive current and
phase C is provided with negative current for the SR motor of Fig. 2B.
Figs. 2J illustrates exemplary flux paths for a rotor mechanical angle of 45° and 225°
as the maximum mutual inductance position when phase A is provided with positive current and
phase C is provided with negative current for the SR motor of Fig. 2B.
Figs. 2K illustrates exemplary flux paths for a rotor mechanical angle of 60° and 240°
as the minimum mutual inductance position when phase B is provided with positive current and
phase A is provided with negative current for the SR motor of Fig. 2B.
Figs. 2L illustrates exemplary flux paths for a rotor mechanical angle of 75° and 255°
as the maximum mutual inductance position when phase B is provided with positive current and
phase C is provided with negative current for the SR motor of Fig. 2B.
Figs. 2M illustrates exemplary flux paths for a rotor mechanical angle of 90° and 270°
as the minimum mutual inductance position when phase C is provided with positive current and
phase A is provided with negative current for the SR motor of Fig. 2B.
Figs. 2N illustrates exemplary flux paths for a rotor mechanical angle of 105° and 285°
as the maximum mutual inductance position when phase B is provided with positive current and
phase A is provided with negative current for the SR motor of Fig. 2B.
Figs. 2O illustrates exemplary flux paths for a rotor mechanical angle of 120° and 300°
as the minimum mutual inductance position when phase C is provided with positive current and
phase B is provided with negative current for the SR motor of Fig. 2B.
Figs. 2P illustrates exemplary flux paths for a rotor mechanical angle of 135° and 315°
as the maximum mutual inductance position when phase C is provided with positive current and
phase A is provided with negative current for the SR motor of Fig. 2B.
Figs. 2Q illustrates exemplary flux paths for a rotor mechanical angle of 150° and 330°
as the minimum mutual inductance position when phase A is provided with positive current and
phase B is provided with negative current for the SR motor of Fig. 2B.
Figs. 2R illustrates exemplary flux paths for a rotor mechanical angle of 165° and 345°
as the maximum mutual inductance position when phase C is provided with positive current and
phase B is provided with negative current for the SR motor of Fig. 2B.
7.2 MOTOR ASSEMBLY
Fig. 3A is a perspective view of an example motor assembly in some implementations
of the present technology.
Fig. 3B is a cross sectional view of the motor assembly of Fig. 3A.
Fig. 3C and 3D show outside and inside perspective views respectively of an end bell
housing component of the motor assembly of Fig. 3A.
Fig. 3E and 3F show outside and inside perspective views respectively of a housing of
the motor assembly of Fig. 3A.
Fig. 3G is an perspective view of an example rotor assembly for the motor assembly
of Fig. 3A.
Fig 3H is a perspective view of an example stator suitable for implementation in the
motor assembly of Fig. 3A.
Fig. 3I is a schematic plan view of the stator assembly of Fig. 3H illustrating inclusion
of phase coils.
Fig. 3J is a top view illustration of a wound stator.
7.3 SYSTEM
Fig. 4 shows a system in accordance with the present technology. A patient 1000
wearing a patient interface 3000, receives a supply of air at positive pressure from a PAP device
4000. Air from the PAP device is humidified in a humidifier 5000, and passes along an air circuit
4170 to the patient 1000. A bed partner 1100 may also be present when the patient uses the system.
7.4 PAP DEVICE
Fig. 5A shows a PAP device in accordance with one form of the present technology.
Fig. 5B shows a schematic diagram of the pneumatic circuit of a PAP device in
accordance with one form of the present technology. The directions of upstream and downstream
are indicated.
Fig. 5C shows a schematic diagram of the electrical components of a PAP device in
accordance with one aspect of the present technology.
Fig. 5D shows a schematic diagram of the algorithms implemented in a PAP device in
accordance with an aspect of the present technology. In this figure, arrows with solid lines indicate
an actual flow of information, for example via an electronic signal.
Fig. 5E is a flow chart illustrating a method carried out by the therapy engine module
of Fig. 5D in accordance with one form of the present technology.
7.5 HUMIDIFIER
Fig. 6A shows a humidifier in accordance with one aspect of the present technology.
Fig. 6B shows a schematic of a humidifier.
8 DETAILED DESCRIPTION OF EXAMPLES OF THE TECHNOLOGY
Before the present technology is described in further detail, it is to be understood that
the technology is not limited to the particular examples described herein, which may vary. It is also
to be understood that the terminology used in this disclosure is for the purpose of describing only
the particular examples discussed herein, and is not intended to be limiting.
8.1 SWITCHED RELUCTANCE MOTOR
8.1.1 Stator
In one form, the present technology comprises a switched reluctance motor including
a stator having distributed coil windings. In a case of a distributed windings configuration, the
coils are placed or wound into the slots. With such a distributed winding, each coil winding may
encircle or encompass at least two stator teeth (or more) while skipping over at least one stator slot
(or more). The coils may have full pitch or fractional pitch. The number of slots that are occupied
with the coils of one phase depend on the number of rotor poles and a winding distribution
parameter. The winding distribution parameter indicates how many adjacent slots are occupied
with coil segments of the same phase.
In the exemplary stator assemblies as shown in Figs. 2A and 2B the winding
distribution parameter is 1 as each coil segment (i.e., the coil portion within a stator slot) for each
phase is adjacent a coil segment from another phase and not adjacent another coil segment from
the same phase. There may be one or more coils for the same phase and coils from the same phase
are referred to as a coil group. Each coil group comprises at least one coil, such as one, two, three,
four, five or more coils per coil group. Each of the coils in a coil group includes two coil segments
(i.e. a pair of coil segments) provided in different stator slots.
Fig. 2A shows a stator and rotor configuration for a three phase SR motor having 6
stator poles (6 stator teeth 120 and 6 stator slots 122) and 2 rotor poles 130 according to an example
of the present technology. In Fig. 2A, each phase includes one coil for each phase and the coil is
wound with two coil segments within two stator slots 122. The segments are connected by the end
turns of the winding which is not shown in the figure. The A phase coil includes A+ and A- coils
segments 110a, 110b respectively located within stator slots between stator teeth 1 & 6 and stator
teeth 3 & 4 respectively. The B phase coil includes B+ and B- coil segments, 112a, 112b
respectively that are located within stator slots between stator teeth 4 & 5 and stator teeth 1 & 2
respectively. The C phase coil includes C+ and C- coil segments 114a, 114b respectively that are
located within stator slots between stator teeth 2 & 3 and stator teeth 5 & 6. Thus, each stator coil
is located in a slot between two stator teeth and adjacent winding coils from different phases share
an association with stator teeth that separate them. In this configuration, each stator coil segment
from the same phase is separated from the other stator coil segment of the same phase by three
stator teeth. The coils are not wound around a single stator tooth.
Figs. 2B and 2C illustrate a stator and rotor configuration for a three phase SR motor
having 12 stator poles (12 stator teeth 220 and 12 stator slots 222) and 4 rotor poles 230 according
to another example of the present technology. In Fig. 2C the slots are numbered "1" through "12"
and each tooth, although not shown with a number, may be considered to have the same number
as the numbered slot to the left of the tooth. (i.e., stator tooth 1 is between stator slots 1 and 2, etc.)
In this arrangement there are two coil winding groups for each phase, each group includes one coil
formed of two coil segments that occupy two stator slots. The coil segments are distributed evenly
around the stator and each coil segment for a single phase is separated by three stator teeth. In Fig.
2C, stator slots numbered 2 and 12 and coil 214b are each shown twice simply for purposes of
more clearly illustrating the coil windings pattern. For example, phase A coil segments 210a and
210b are separated by stator teeth 1, 2 and 3 are wound through slots numbered 1 and 4 to be
located in slots 1 and 4. In the illustrated example phase A coil segments 210a, 210b, 210c and
210d are located in stator slots 1, 4, 7 and 10, between stator teeth 12 and 1; 3 and 4; 6 and 7; and
9 and 10 respectively. Phase B coil segments 212a, 212b, 212c and 21d are located in slots 9, 12,
3 and 6, between stator teeth 8 and 9; 11 and 12; 2 and 3; and 5 and 6 respectively. Phase C coil
segments 214a, 214b, 214c and 214d are located in slots 11, 2, 5 and 8, between stator teeth 10 and
11, 1 and 2; 4 and 5; and 7 and 8 respectively. Thus, each stator slot includes a single coil segment
from one coil. A skilled addressee would appreciate that the coils or coil segments for the different
phases may be arranged in a different order.
Although Figs. 2A and 2B refer to three phase motors (i.e., phases A B and C), it is to
be understood that the motor may comprise a different number of phases such as two, four, five or
more phases. The number of stator slots or stator teeth for different SR motor configurations may
be determined as a function of the number of phases and the number of rotor poles. The winding
distribution parameter may also be used in this determination for example using the following
equation:
Total number of stator slots = number of phases X number of rotor poles X winding
distribution parameter.
Thus, the total number of stator slots may be a multiple of number of phases and number of rotor
poles of the motor. Moreover, the total number of stator slots may be a multiple of a winding
distribution parameter.
The stator is formed as a lamination stack for example of steel laminations such as
silicon steel e.g. M19 grade silicon steel (M19_29G). The rotor may be formed of the same material
as the stator or another type of ferromagnetic material like ferrite or iron cobalt alloys. The coils
may be formed of any wire gauge preferably in the range of 26 to 32 gauge wire, for example, each
of the coils may be formed from American wire gauge (AWG) 30. The number of turns of the
wire is determined by the voltage of the motor. For example the coils may include 30-40 turns per
coils such as 34 turns per coil. In some cases, each turn of the coil may have one or more wires in
hand such as a number in a range of 2 to 10 wires in hand per turn. For example, it may have six
wires in hand per turn. Thus, in one example winding, the wire may be AWG 30, and each coil
may have 34 turns with 6 wires in hand. However, a skilled addressee would understand that the
coils may be formed of other material and include a different number of turns per coil and number
of wires etc.
A SR motor having a distributed winding configuration distributes the flux between
the teeth that each of the phase coils is associated rather than concentrating the flux in a single
stator tooth. This results in the radial electromagnetic forces acting between the stator and the rotor
being distributed along the stator teeth that are associated with the energized coils. Thus, in the
three phase stator arrangement illustrated in Fig. 2B the electromagnetic force is applied to four
teeth with a 90° mechanical phase shift at the same time, see Figs. 2G to 2R. In contrast a
conventional three phase concentrated stator as in Fig. 1 applies the electromagnetic force to two
teeth with a 180° phase shift at the same time. Therefore in the exemplary SR motor with
distributed windings the peak radial force applied to each tooth is less than in a conventional
concentrated winding. In other words, the distribution permits a reduction in radial forces. For
example in a SR motor comprising a 12/4 rotor configuration as illustrated in Fig. 2B the peak
radial force in each tooth may be 329 Newtons compared to 518N per tooth in a 6/4 concentrated
winding conventional SR motor as illustrated in Fig. 1. The distribution of the radial
electromagnetic forces reduces vibration and consequently reduces noise produced from the SR
motor.
The SR motor including a distributed winding configuration of the present technology
may have a low aligned to unaligned inductance ratio, such as an inductance ratio of less than 3,
or less than 2.5 e.g. between 2 and 2.5.
Advantageously the SR motor including a distributed winding configuration according
to the present technology allows for smaller lower power SR motors to be made that produce
enough torque to run small high speed devices (up to 60,000 rpm). A small SR motor is understood
to mean a SR motor having a stator outer diameter of less than 50 mm, such as 48 mm, 47 mm, 46
mm, 45 mm, 44 mm, 43 mm or less. However, it is to be understood that a SR motor having a
distributed winding configuration may also be used in larger motors than have stator outer
diameters greater than 50 mm.
8.1.2 Rotor
The rotor includes at least two rotor poles 130, 230, the rotor poles form rotor teeth
that extend out from a central rotor core. In Fig. 2A, the rotor has two rotor teeth 131-1, 131-2. In
Fig. 2B, the rotor has four rotor teeth 131-1, 131-2, 131-3, 131-4. Each of the rotor teeth may have
a width that is wider than the width of a single stator tooth. This can help to distribute the radial
electromagnetic forces acting between the stator and the rotor between multiple stator teeth that
are associated with the energized coils. In this example of Fig. 2B, the width of a rotor tooth may
be approximately equal to the width of a stator tooth (e.g., the length of the inner arc surface of an
end of the stator tooth) plus some width such as a function of a measure of the width of the gap
between adjacent stator teeth. The gap 233 being the stator slot width at the inner end of the stator
slot (the inner end being the end closest to the rotor). For example, the width of a rotor tooth may
be approximately equal to the width of the stator tooth plus a multiple (e.g., two times) of the width
of the gap between stator teeth. In this regard, the rotor width may be understood to refer to a
length along a surface at an end of the rotor tooth that may be formed as an arc at an end of each
tooth of the rotor.
In some versions of the present technology, each stator tooth may have tooth tips 213a,
213b (labeled in Fig. 2B) that form projections on either side of a stator tooth and that extend the
width of the stator while still permitting a gap between the stator teeth. The teeth tips can serve to
smooth the field in air gap between stator teeth and help to reduce noise. The tips may also help
with keeping the winding in the gap or helping to prevent the winding from shifting to the rotor
area of the bore. In some versions of the present technology, a suitable stator tooth width may be
about 2.4 mm. However, other widths may be employed, such as a width in a range of 1.75 mm
to 5 mm. That stator tooth width may increase by the width of the tooth tips when included. In
some cases, the rotor pole width may be about 7 mm. However, other widths may be employed,
such as a width in a range of 5 mm to 10 mm.
The central angles of the stator and rotor poles may be as significant as absolute width
values of the teeth. For example, in some typical motor designs, the central angle of the stator and
rotor poles may be approximately the same or have a very small difference between them such as
a few degrees. However, in some versions of the present technology, the angles may be
significantly different, such as having an angle difference of more than several degrees (e.g., more
than 5 degrees such as in a difference range from 3 degrees to 40 degrees, or such as in a difference
range of 5 degrees to 30 degrees. For example, the stator central angle, such as the angle formed
from the center of the stator with imaginary lines extending radially to the edges of a stator's tooth
or stator's tips (see, e.g., angle SA illustrated in Fig. 2B) may be about 13 degrees (e.g., 13.12°).
In such an example, the rotor central angle, such as the angle formed from the center of the rotor
with imaginary lines extending radially to the edges of a rotor's tooth (see, e.g., angle RA illustrated
in Fig. 2B) may be about 40 degrees (e.g., 40.14 °). Such a difference between the stator central
angle and rotor central angle is very significant (e.g., approximately 27 degrees).
The rotor may be formed of a suitable material such as silicon steel e.g. M19 grade
silicon steel (M19_29G) or another type of ferromagnetic material like ferrite or iron cobalt alloys.
8.1.3 Motor Control
As mentioned previously, torque in SR motors is proportional to the difference in a
phase self-inductances in an aligned and non-aligned position when the appropriate phase is
energized. It has been determined that using a distributed stator winding configuration in a SR
motor of the present technology may produce a significant mutual inductance variation between
certain positions of the rotor. This mutual inductance may be utilized to produce a higher torque
at small power (less than hundred watts such as 90 Watts, 60 Watts or 50 Watts) SR motor design.
Fig. 2D illustrates an example of the self and mutual inductances produced in a SR motor according
to the present technology. The self-inductances Laa, Lbb and Lcc show significantly less variation
in the inductance generated at the different rotor positions than the mutual inductances Lab, Lac
and Lbc. The mutual inductance variation is approximately eight times the variation range
generated by the self-inductances in the example shown. As torque is proportional to the difference
of align and non-align values of the inductance in SR motors the mutual inductance may be utilised
to produce a larger portion of the torque. The total torque produced in the motor is the sum of the
components related to self-inductance and the mutual inductance.
The stator of the SR motor of the present technology includes at least three motor
phases. Due to the mutual inductance producing a large portion of the torque, the SR motor of the
present technology may be configured to energize two phases at the same time during each
conduction period. A first phase may be energized with a positive direction current and a second
phase may be energized with a negative direction current resulting in a net flux increase in the
motor and producing a higher torque. Two phases are energised at the same time and follow a
specific sequence to cause the rotor to rotate. Each phase of the motor may be energized with the
same current value during at least two consecutive conduction periods. For example in some
configurations one of the two energized phases is switched off to a non-energized state and one of
the non-energized phases is switched on to an energized state during each commutation period.
The timing of the commutation period or switching is controlled to facilitate smooth rotation of
the motor and reduce cogging.
Fig 2E shows an exemplary commutation for a SR motor comprising a distributed
stator as shown in Fig. 2B. In a first step phase A may be energised with a positive direction
current, phase B may be energised with a negative direction current and phase C may be non-
energised (zero current) (i.e., A+B-). This will cause the rotor to move towards the alignment
position shown in Fig. 2H. In the second step, phase A may continue to be energised with a positive
direction current, phase B is switched off to an non-energized state (zero current) and phase C is
energized with a negative direction current (i.e. A+C-). This will cause the rotor to move towards
the alignment positions shown in Fig. 2J. In the third step, the phase A is switched off to an non-
energized state (zero current), phase B is energized with a positive direction current and phase C
continues to be energized with a negative direction current (i.e. B+C-). This will cause the rotor
to move towards the alignment position shown in Fig. 2L. This sequential switching of the phases
continues such that the fourth step would be B+A- causing the rotor to move towards the alignment
position shown in Fig. 2N. The fifth step, C+A-, causing the rotor to move towards the alignment
position shown in Fig. 2P. The sixth step, C+B-, causing the rotor to move towards the alignment
position shown in Fig. 2R. Then the cycle repeats again by returning to A+B- to provide a full
360° revolution of the rotor. The specific timing of the switching or commutation of the
energization of the phases may be varied to adjust the performance of the motor and reduce torque
ripple.
Fig. 2F shows an example of the torque produced for different current sequences
relative to the rotor position in a SR motor comprising a stator and rotor configuration as shown in
Fig. 2B. For example for a rotor position between 8° to 38°, the slope of Lac produces the largest
proportion of the torque.
1 � � � � � �
� = � + � � + � � ,
� � � � � �
Where Ta the instantaneous torque value, � � ��� � are instantaneous values of the current in
� , � �
phases A, B and C respectively. � is the total inductance of phase A. � is the mutual inductance
between phases A and B and � is the mutual inductance between phases A and C respectively.
�� ��
�� �� ��
�� �� ��
In contrast in a conventional SR motor, where only the self-inductance component is
1 � �
producing the torque, i.e. T = ( � ).
A method of controlling a switched reluctance motor comprising at least three phases
may include during each conduction period energizing a first phase with a negative direction
current, energizing a second phase with a positive current and having at least one non-energized
phase and during each commutation period switching off one of the first phase or the second phase
to a non-energized state and switching on one of the non-energized phases to an energized state
with the same direction current as the first or second phase that was switched off. The switched
reluctance motor may include a distributed winding configuration as described above.
In some aspects of the present technology the SR motor may be controlled using a
sensorless control. In this arrangement when the rotor passes the non-energized phase, the back
EMF, induced in the phase can be detected and filtered in order to remove the noise. The signal is
proportional to the rotor angle and may be used to estimate the position of the rotor.
8.1.4 Motor Assembly
An example of a motor assembly 3002 that may be implemented with the switched
reluctance motor technology described herein is illustrated in Figs. 3A through 3J. As seen in Fig.
3A and 3B, the motor assembly 3002 may include a motor housing 3100, an end bell 3110 and one
or more impeller(s) 3120. An example end bell is shown in Figs. 3C and 3D. An example motor
housing is illustrated in Figs. 3E and 3F. The motor assembly may also optionally include an
encoder 3130, such as an optical encoder to detect rotation and/or positioning (e.g., absolute or
relative movement) of the shaft of the rotor assembly. As seen in Fig. 3B, a housing of the encoder
may be coupled to the end bell 3110 with one or more fasteners, such as screws 3132a.
Corresponding fastener holes 3135 on the end bell 3110 and motor housing 3100 as seen in Figs.
3A, 3C, 3D and 3F receive additional fasteners, such as screws 3132b etc., for joining and holding
the end bell 3110 and motor housing 3100 together. Other types of fasteners may also be
implemented such as bolts, snap fit structures, clips, rivets, etc. for joining the structures of the
motor assembly. As shown in Fig. 3f, the motor housing may optionally include a wiring aperture
3235. The wiring aperture can permit lead wires of the coils of the stator assembly to pass out of
the motor assembly when the stator assembly is installed within the motor assembly.
As seen in more detail in the cross sectional view of Fig. 3B, the motor housing 3100
and end bell 3110 may contain the stator assembly 3140 and rotor assembly 3150 (on Fig. 3G).
(the rotor assembly 3150 is not shown in Fig. 3B). The stator assembly 3140 may include a stator
3141 and coils in any configuration as previously described such as the stator configuration
illustrated in Fig. 2B. As illustrated in Fig. 3H, the stator 3141 of such a stator assembly, like the
rotor, can be formed in a laminated stack. An example coil configuration is illustrated in Figs. 3I
and 3J showing the stator 3141 with stator teeth 220 and stator slots 222. Coil groups for phases
A, B and C are shown.
The rotor assembly 3150 may include a rotor in any configuration as previously
described such as the rotor configuration also illustrated in Fig. 2B. In this regard, the rotor
assembly may include a rotor 3152 and shaft 3154 as illustrated in Fig. 3G. As illustrated, the rotor
may be a laminated rotor stack (e.g., a plurality of stacked plates) that are bonded to the shaft using
a primer and adhesive. The rotor assembly may be mounted for rotation within the motor housing
3100 and end bell 3110 with a set of bearings 3160a, 3160b through which the shaft ends are
inserted. The bearings 3160a, 3160b may each reside in a cylindrical bearing seat 3161a, 3161b
in each of the end bell 3110 and the motor housing 3100 respectively. The shaft may also be
positioned within the assembly with a spring 3162. The impeller(s) 3120 may be press fit at an
impeller end of the shaft 3154 opposite an encoder end of the shaft 3154. Alternatively, the shaft
may have impellers at both ends of the shaft (not shown). The rotor assembly may also include
one or more balance rings 3164a, 3164b. The motor assembly or the impeller(s) may be inserted
or positioned within a volute such as the example volute illustrated in Fig. 5A so that the motor
assembly may serve as part of a blower of a flow generator.
8.2 TREATMENT SYSTEMS
In one form, the present technology comprises apparatus for treating a respiratory
disorder. The apparatus may comprise a flow generator or blower including a switched reluctance
motor for supplying pressurised respiratory gas, such as air, to the patient 1000 via an air delivery
tube 4170 leading to a patient interface 3000.
8.3 THERAPY
In one form, the present technology comprises method for treating a respiratory
disorder comprising the step of applying positive pressure to the entrance of the airways of a patient
1000 using a pressure device including a switched reluctance motor.
8.3.1 Nasal CPAP for OSA
In one form, the present technology comprises a method of treating Obstructive Sleep
Apnea in a patient by applying nasal continuous positive airway pressure to the patient using a
patient interface.
In certain embodiments of the present technology, a supply of air at positive pressure
is provided to the nasal passages of the patient via one or both nares.
A patient interface 3000 is provided as seen in Fig. 4 to deliver the supply of
pressurized air to the patient’s airways. A number of different types of patient interfaces including
non-invasive and invasive interfaces are available. For example non-invasive masks include a
nasal mask, full face mask, nasal prongs and nasal pillows and invasive interfaces include a
tracheostomy tube. Non-invasive patient interfaces 3000 comprise a seal-forming structure to
engage with a patient’s face in use.
8.4 PAP DEVICE 4000
As shown in Figs. 5A to 5D a PAP device 4000 in accordance with one aspect of the
present technology comprises mechanical and pneumatic components 4100, electrical components
4200 and is programmed to execute one or more algorithms 4300. The PAP device preferably has
an external housing 4010, preferably formed in two parts, an upper portion 4012 of the external
housing 4010, and a lower portion 4014 of the external housing 4010. In alternative forms, the
external housing 4010 may include one or more panel(s) 4015. Preferably the PAP device 4000
comprises a chassis 4016 that supports one or more internal components of the PAP device 4000.
In one form a pneumatic block 4020 is supported by, or formed as part of the chassis 4016. The
PAP device 4000 may optionally include a handle 4018.
The pneumatic path of the PAP device 4000 preferably comprises an inlet air filter
4112, an inlet muffler 4122, a controllable pressure device 4140 capable of supplying air at positive
pressure (preferably a blower 4142) including a motor 4144, and an outlet muffler 4124. One or
more transducers 4270 such as pressure sensors 4274, flow sensors 4272 and speed sensors 4276
are included in the pneumatic path.
The preferred pneumatic block 4020 comprises a portion of the pneumatic path that is
located within the external housing 4010.
The PAP device 4000 may include an electrical power supply 4210, one or more input
devices 4220, a central controller 4230, a therapy device controller 4240, a therapy device 4245,
one or more protection circuits 4250, memory 4260, transducers 4270, data communication
interface 4280 and one or more output devices 4290. Electrical components 4200 may be mounted
on a single Printed Circuit Board Assembly (PCBA) 4202. In an alternative form, the PAP device
4000 may include more than one PCBA 4202.
The central controller 4230 of the PAP device 4000 is programmed to execute one or
more algorithm modules 4300, preferably including a pre-processing module 4310, a therapy
engine module 4320, a therapy control module 4330, and further preferably a fault condition
module 4340.
8.4.1 PAP device mechanical & pneumatic components 4100
8.4.1.1 Air filter(s) 4110
A PAP device in accordance with one form of the present technology may include an
air filter 4110, or a plurality of air filters 4110.
In one form, an inlet air filter 4112 is located at the beginning of the pneumatic path
upstream of a blower 4142. See Fig. 5B.
In one form, an outlet air filter 4114, for example an antibacterial filter, is located
between an outlet of the pneumatic block 4020 and a patient interface 3000. See Fig. 5B.
8.4.1.2 Muffler(s) 4120
In one form of the present technology, an inlet muffler 4122 is located in the pneumatic
path upstream of a blower 4142. See Fig. 5B.
In one form of the present technology, an outlet muffler 4124 is located in the
pneumatic path between the blower 4142 and a patient interface 3000. See Fig. 5B.
8.4.1.3 Pressure device 4140
In a preferred form of the present technology, a pressure device 4140 for producing a
flow of air at positive pressure is a controllable blower 4142. For example the blower may include
a switched reluctance motor 4144 with one or more impellers housed in a volute. The blower may
be preferably capable of delivering a supply of air, for example about 120 litres/minute, at a
positive pressure in a range from about 4 cmH O to about 20 cmH O, or in other forms up to about
cmH O.
The pressure device 4140 is under the control of the therapy device controller 4240.
8.4.1.4 Transducer(s) 4270
In one form of the present technology, one or more transducers 4270 are located
upstream of the pressure device 4140. The one or more transducers 4270 are constructed and
arranged to measure properties of the air at that point in the pneumatic path.
In one form of the present technology, one or more transducers 4270 are located
downstream of the pressure device 4140, and upstream of the air circuit 4170. The one or more
transducers 4270 are constructed and arranged to measure properties of the air at that point in the
pneumatic path.
In one form of the present technology, one or more transducers 4270 are located
proximate to the patient interface 3000.
8.4.1.5 Anti-spill back valve 4160
In one form of the present technology, an anti-spill back valve is located between the
humidifier 5000 and the pneumatic block 4020. The anti-spill back valve is constructed and
arranged to reduce the risk that water will flow upstream from the humidifier 5000, for example to
the motor 4144.
8.4.1.6 Air circuit 4170
An air circuit 4170 in accordance with an aspect of the present technology is
constructed and arranged to allow a flow of air or breathable gasses between the pneumatic block
4020 and the patient interface 3000.
8.4.1.7 Oxygen delivery 4180
In one form of the present technology, supplemental oxygen 4180 is delivered to a
point in the pneumatic path.
In one form of the present technology, supplemental oxygen 4180 is delivered
upstream of the pneumatic block 4020.
In one form of the present technology, supplemental oxygen 4180 is delivered to the
air circuit 4170.
In one form of the present technology, supplemental oxygen 4180 is delivered to the
patient interface 3000.
8.4.2 PAP device electrical components 4200
8.4.2.1 Power supply 4210
Power supply 4210 supplies power to the other components of the basic PAP device
4000: the input device 4220, the central controller 4230, the therapy device 4245, and the output
device 4290.
In one form of the present technology, power supply 4210 is internal of the external
housing 4010 of the PAP device 4000. In another form of the present technology, power supply
4210 is external of the external housing 4010 of the PAP device 4000.
In one form of the present technology power supply 4210 provides electrical power to
the PAP device 4000 only. In another form of the present technology, power supply 4210 provides
electrical power to both PAP device 4000 and humidifier 5000.
8.4.2.2 Input device(s) 4220
A PAP device 4000 may include one or more input devices 4220. Input devices 4220
comprises buttons, switches or dials to allow a person to interact with the PAP device 4000. The
buttons, switches or dials may be physical devices, or software devices accessible via a touch
screen. The buttons, switches or dials may, in one form, be physically connected to the external
housing 4010, or may, in another form, be in wireless communication with a receiver that is in
electrical connection to the central controller 4230.
In one form the input device 4220 may be constructed and arranged to allow a person
to select a value and/or a menu option.
8.4.2.3 Central controller or Processor 4230
In one form of the present technology, the central controller or processor 4230 is a
dedicated electronic circuit configured to receive input signal(s) from the input device 4220, and
to provide output signal(s) to the output device 4290 and / or the therapy device controller 4240.
In one form, the central controller 4230 is an application-specific integrated circuit. In
another form, the central controller 4230 comprises discrete electronic components.
In one form of the present technology, the central controller 4230 is a processor suitable
to control a PAP device 4000 such as an x86 INTEL processor.
A processor 4230 suitable to control a PAP device 4000 in accordance with another
form of the present technology includes a processor based on ARM Cortex-M processor from
ARM Holdings. For example, an STM32 series microcontroller from ST MICROELECTRONICS
may be used.
Another processor 4230 suitable to control a PAP device 4000 in accordance with a
further alternative form of the present technology includes a member selected from the family
ARM9-based 32-bit RISC CPUs. For example, an STR9 series microcontroller from ST
MICROELECTRONICS may be used.
In certain alternative forms of the present technology, a 16-bit RISC CPU may be used
as the processor 4230 for the PAP device 4000. For example a processor from the MSP430 family
of microcontrollers, manufactured by TEXAS INSTRUMENTS, may be used.
The processor 4230 is configured to receive input signal(s) from one or more
transducers 4270, and one or more input devices 4220.
The processor 4230 is configured to provide output signal(s) to one or more of an
output device 4290, a therapy device controller 4240, a data communication interface 4280 and
humidifier controller 5250.
In some forms of the present technology, the processor 4230, or multiple such
processors, is configured to implement the one or more methodologies described herein such as
the one or more algorithms 4300 expressed as computer programs stored in a non-transitory
computer readable storage medium, such as memory 4260. In some cases, as previously discussed,
such processor(s) may be integrated with a PAP device 4000. However, in some forms of the
present technology the processor(s) may be implemented discretely from the flow generation
components of the PAP device 4000, such as for purpose of performing any of the methodologies
described herein without directly controlling delivery of a respiratory treatment. For example,
such a processor may perform any of the methodologies described herein for purposes of
determining control settings for a ventilator or other respiratory related events by analysis of stored
data such as from any of the sensors described herein.
Preferably PAP device 4000 includes a clock 4232 that is connected to the central
controller 4230.
8.4.2.4 Therapy device 4245
In one form of the present technology, the therapy device 4245 is configured to deliver therapy to
a patient 1000 under the control of the central controller 4230. Preferably the therapy device 4245
is a positive air pressure device 4140.
8.4.2.5 Therapy device controller 4240
In one form of the present technology, therapy device controller 4240 is a therapy
control module 4330 such as for pressure control that forms part of the algorithms 4300 executed
by the processor 4230.
In one form of the present technology, therapy device controller 4240 is a dedicated
motor control integrated circuit. For example, in one form a MC33035 brushless DC motor
controller, manufactured by ONSEMI is used.
8.4.2.6 Protection circuits 4250
Preferably a PAP device 4000 in accordance with the present technology comprises
one or more protection circuits 4250.
One form of protection circuit 4250 in accordance with the present technology is an
electrical protection circuit.
One form of protection circuit 4250 in accordance with the present technology is a
temperature or pressure safety circuit.
8.4.2.7 Memory 4260
In accordance with one form of the present technology the PAP device 4000 includes
memory 4260, preferably non-volatile memory. In some forms, memory 4260 may include battery
powered static RAM. In some forms, memory 4260 may include volatile RAM.
Preferably memory 4260 is located on PCBA 4202. Memory 4260 may be in the form
of EEPROM, or NAND flash.
Additionally or alternatively, PAP device 4000 includes removable form of memory
4260, for example a memory card made in accordance with the Secure Digital (SD) standard.
In one form of the present technology, the memory 4260 acts as a non-transitory
computer readable storage medium on which is stored computer program instructions expressing
the one or more methodologies described herein, such as the one or more algorithms 4300.
8.4.2.8 Transducers 4270
Transducers may be internal of the device, or external of the PAP device. External
transducers may be located for example on or form part of the air delivery circuit, e.g. the patient
interface. External transducers may be in the form of non-contact sensors such as a Doppler radar
movement sensor that transmit or transfer data to the PAP device.
8.4.2.8.1 Flow
A flow transducer 4272 in accordance with the present technology may be based on a
differential pressure transducer, for example, an SDP600 Series differential pressure transducer
from SENSIRION. The differential pressure transducer is in fluid communication with the
pneumatic circuit, with one of each of the pressure transducers connected to respective first and
second points in a flow restricting element. Other flow sensors may also be implemented such as
a hot wire flow sensor.
In use, a signal representing total flow Qt from the flow transducer 4272 is received by
the processor 4230.
8.4.2.8.2 Pressure
A pressure transducer 4274 in accordance with the present technology is located in
fluid communication with the pneumatic circuit. An example of a suitable pressure transducer is a
sensor from the HONEYWELL ASDX series. An alternative suitable pressure transducer is a
sensor from the NPA Series from GENERAL ELECTRIC.
In use, a signal from the pressure transducer 4274, is received by the processor 4230.
In one form, the signal from the pressure transducer 4274 is filtered prior to being received by the
processor 4230.
8.4.2.8.3 Motor speed
In one form of the present technology a motor speed signal 4276 is generated. A motor
speed signal 4276 is preferably provided by therapy device controller 4240. Motor speed may, for
example, be generated by a speed sensor, such as a Hall effect sensor.
8.4.2.9 Data communication systems
In one preferred form of the present technology, a data communication interface 4280
is provided, and is connected to processor 4230. Data communication interface 4280 is preferably
connectable to remote external communication network 4282. Data communication interface 4280
is preferably connectable to local external communication network 4284. Preferably remote
external communication network 4282 is connectable to remote external device 4286. Preferably
local external communication network 4284 is connectable to local external device 4288.
In one form, data communication interface 4280 is part of processor 4230. In another
form, data communication interface 4280 is an integrated circuit that is separate from processor
4230.
In one form, remote external communication network 4282 is the Internet. The data
communication interface 4280 may use wired communication (e.g. via Ethernet, or optical fibre)
or a wireless protocol to connect to the Internet.
In one form, local external communication network 4284 utilises one or more
communication standards, such as Bluetooth, or a consumer infrared protocol.
In one form, remote external device 4286 is one or more computers, for example a
cluster of networked computers. In one form, remote external device 4286 may be virtual
computers, rather than physical computers. In either case, such remote external device 4286 may
be accessible to an appropriately authorised person such as a clinician.
Preferably local external device 4288 is a personal computer, mobile phone, tablet or
remote control.
8.4.2.10 Output devices including optional display, alarms
An output device 4290 in accordance with the present technology may take the form
of one or more of a visual, audio, and haptic output. A visual output may be a Liquid Crystal
Display (LCD) or Light Emitting Diode (LED) display. An audio output may be a speaker or audio
tone emitter.
8.4.2.10.1 Display driver 4292
A display driver 4292 receives as an input the characters, symbols, or images intended
for display on the display 4294, and converts them to commands that cause the display 4294 to
display those characters, symbols, or images.
8.4.2.10.2 Display 4294
A display 4294 is configured to visually display characters, symbols, or images in
response to commands received from the display driver 4292. For example, the display 4294 may
be an eight-segment display, in which case the display driver 4292 converts each character or
symbol, such as the figure “0”, to eight logical signals indicating whether the eight respective
segments are to be activated to display a particular character or symbol.
8.4.3 PAP device algorithms 4300
8.4.3.1 Pre-processing module 4310
An pre-processing module 4310 in accordance with the present technology receives as
an input, raw data from a transducer, for example a flow or pressure transducer, and preferably
performs one or more process steps to calculate one or more output values that will be used as an
input to another module, for example a therapy engine module 4320.
In one form of the present technology, the output values include the interface or mask
pressure Pm, the respiratory flow Qr, and the leak flow Ql.
In various forms of the present technology, the pre-processing module 4310 comprises
one or more of the following algorithms: pressure compensation algorithm 4312, vent flow
calculation algorithm 4314, leak flow algorithm 4316 and respiratory flow algorithm 4318.
A pressure compensation algorithm 4312 may receive as an input a signal indicative
of the pressure in the pneumatic path proximal to an outlet of the pneumatic block. The pressure
compensation algorithm 4312 estimates the pressure drop in the air circuit 4170 and provides as
an output an estimated pressure, Pm, in the patient interface 3000.
A vent flow calculation algorithm 4314 may receive as an input an estimated pressure,
Pm, in the patient interface 3000 and estimates a vent flow of air, Qv, from a vent 3400 in a patient
interface 3000.
A leak flow algorithm 4316 may receive as an input a total flow, Qt, and a vent flow
Qv, and provides as an output a leak flow Ql by calculating an average of Qt-Qv over a period
sufficiently long to include several breathing cycles, e.g. about 10 seconds.
A respiratory flow algorithm 4318 may receive as an input a total flow, Qt, a vent flow,
Qv, and a leak flow, Ql, and estimates a respiratory flow of air, Qr, to the patient, by subtracting
the vent flow Qv and the leak flow Ql from the total flow Qt.
8.4.3.2 Therapy Engine Module 4320
In one form of the present technology, a therapy engine module 4320 may receive as
inputs one or more of a pressure, Pm, in a patient interface 3000, and a respiratory flow of air to a
patient, Qr, and provides as an output, one or more therapy parameters, such as a CPAP treatment
pressure Pt, a level of pressure support, and a target ventilation.
In various forms of the present technology, the therapy engine module 4320 comprises
one or more of the following algorithms: phase determination 4321, waveform determination 4322,
ventilation determination 4323, flow limitation determination 4324, Apnea/hypopnea
determination 4325, Snore determination 4326, Patency determination 4327 and Therapy
parameter determination 4328.
A phase determination algorithm 4321 may receive as an input a signal indicative of
respiratory flow, Qr, and provides as an output a phase of a breathing cycle of a patient 1000. The
phase output may be a discrete variable with values of one of inhalation, mid-inspiratory pause,
and exhalation. Alternatively the phase output is a continuous variable, for example varying from
0 to 1, or 0 to 2Pi.
In one form, the phase output is determined to have a discrete value of inhalation when
a respiratory flow Qr has a positive value that exceeds a positive threshold. In one form, a phase
is determined to have a discrete value of exhalation when a respiratory flow Qr has a negative
value that is more negative than a negative threshold.
A waveform determination algorithm 4322 may receive as an input a value indicative
of current patient ventilation, Vent, and provides as an output a waveform of pressure vs. phase. A
ventilation determination algorithm 4323 may receive as an input a respiratory flow Qr, and
determines a measure indicative of patient ventilation, Vent. For example the ventilation
determination algorithm 4323 may determine a current value of patient ventilation, Vent, as half
the low-pass filtered absolute value of respiratory flow, Qr.
A flow limitation determination algorithm 4324 may receive as an input a respiratory
flow signal Qr and provides as an output a metric of the extent to which the inspiratory portion of
the breath exhibits inspiratory flow limitation.
An Apnea/hypopnea determination algorithm 4325 may receive as an input a
respiratory flow signal Qr and provide as an output a flag that indicates that an apnea or an
hypopnea has been detected.
An apnea may be said to have been detected when a function of respiratory flow Qr
falls below a flow threshold for a predetermined period of time. The function may determine a
peak flow, a relatively short-term mean flow, or a flow intermediate of relatively short-term mean
and peak flow, for example an RMS flow. The flow threshold may be a relatively long-term
measure of flow.
A hypopnea may be said to have been detected when a function of respiratory flow Qr
falls below a second flow threshold for a predetermined period of time. The function may
determine a peak flow, a relatively short-term mean flow, or a flow intermediate of relatively short-
term mean and peak flow, for example an RMS flow. The second flow threshold may be a relatively
long-term measure of flow. The second flow threshold is greater than the flow threshold used to
detect apneas.
A snore determination algorithm 4326 may receive as an input a respiratory flow signal
Qr and provides as an output a metric of the extent to which snoring is present. Preferably the
snore determination algorithm 4326 comprises the step of determining the intensity of the flow
signal in the range of 30-300 Hz. Further preferably, snore determination algorithm 4326 comprises
a step of filtering the respiratory flow signal Qr to reduce background noise, e.g. the sound of
airflow in the system from the blower. The snore determination algorithm 4326 may comprise
comparing the noise generated during inspiration to the noise generated during expiration to
determine the occurrence of snore, where the noise generated during expiration is considered to
relate to the intrinsic device noise.
In one form an airway patency algorithm 4327 may receive as an input a respiratory
flow signal Qr, and determines the power of the signal in the frequency range of about 0.75Hz and
about 3Hz. The presence of a peak in this frequency range is taken to indicate an open airway. The
absence of a peak is taken to be an indication of a closed airway.
In one form, the frequency range within which the peak is sought is the frequency of a
small forced oscillation in the treatment pressure Pt. In one implementation, the forced oscillation
is of frequency 2 Hz with amplitude about 1 cmH 0.
In another form, an airway patency algorithm 4327 may receive as an input a
respiratory flow signal Qr, and determines the presence or absence of a cardiogenic signal. The
absence of a cardiogenic signal is taken to be an indication of a closed airway.
A therapy parameter determination algorithm 4328 determines a target treatment
pressure Pt to be delivered by the PAP device 4000. The therapy parameter determination
algorithm 4328 receives as an input one of more of the following:
i. A measure of respiratory phase;
ii. A waveform;
iii. A measure of ventilation;
iv. A measure of inspiratory flow limitation;
v. A measure of the presence of apnea and/or hypopnea;
vi. A measure of the presence of snore; and
vii. A measure of the patency of the airway.
The therapy parameter determination algorithm 4328 determines the treatment
pressure Pt as a function of indices or measures of one or more of flow limitation, apnea, hypopnea,
patency, and snore. In one implementation, these measures are determined on a single breath basis,
rather than on an aggregation of several previous breaths.
Fig. 5E is a flow chart illustrating a method 4500 carried out by the processor 4230 as
one implementation of the algorithm 4328. The method 4500 starts at step 4520, at which the
processor 4230 compares the measure of the presence of apnea / hypopnea with a first threshold,
and determines whether the measure of the presence of apnea / hypopnea has exceeded the first
threshold for a predetermined period of time, indicating an apnea / hypopnea is occurring. If so,
the method 4500 proceeds to step 4540; otherwise, the method 4500 proceeds to step 4530. At
step 4540, the processor 4230 compares the measure of airway patency with a second threshold.
If the measure of airway patency exceeds the second threshold, indicating the airway is patent, the
detected apnea / hypopnea is deemed central, and the method 4500 proceeds to step 4560;
otherwise, the apnea / hypopnea is deemed obstructive, and the method 4500 proceeds to step 4550.
At step 4530, the processor 4230 compares the measure of flow limitation with a third
threshold. If the measure of flow limitation exceeds the third threshold, indicating inspiratory flow
is limited, the method 4500 proceeds to step 4550; otherwise, the method 4500 proceeds to step
4560.
At step 4550, the processor 4230 increases the treatment pressure Pt by a
predetermined pressure increment P, provided the increased treatment pressure Pt would not
exceed an upper limit Pmax. In one implementation, the predetermined pressure increment P
and upper limit Pmax are 1 cmH 0 and 20 cmH 0 respectively. The method 4500 then returns to
step 4520.
At step 4560, the processor 4230 decreases the treatment pressure Pt by a decrement,
provided the decreased treatment pressure Pt would not fall below a lower limit Pmin, such as a
Pmin of 4 cmH 0. The method 4500 then returns to step 4520. In one implementation, the
decrement is proportional to the value of Pt-Pmin, so that the decrease in Pt to the lower limit Pmin
in the absence of any detected events is exponential. Alternatively, the decrement in Pt could be
predetermined, so the decrease in Pt to the lower limit Pmin in the absence of any detected events
is linear.
8.4.3.3 Therapy Control module 4330
A therapy control module 4330 in accordance with one aspect of the present technology
may receive as an input a target treatment pressure Pt, and controls a therapy device 4245 to deliver
that pressure. The therapy control module 4330 may receive as an input an EPAP pressure and an
IPAP pressure, and controls a therapy device 4245 to deliver those respective pressures.
8.4.3.4 Detection of fault conditions
In one form of the present technology, a processor executes one or more methods for
the detection of fault conditions serving as a fault condition module 4340. Preferably the fault
conditions detected by the one or more methods includes at least one of the following:
• Power failure (no power, or insufficient power)
• Transducer fault detection
• Failure to detect the presence of a component
• Operating parameters outside recommended ranges (e.g. pressure, flow, temperature, PaO2)
• Failure of a test alarm to generate a detectable alarm signal.
Upon detection of the fault condition, the corresponding algorithm signals the presence
of the fault by one or more of the following:
• Initiation of an audible, visual &/or kinetic (e.g. vibrating) alarm
• Sending a message to an external device
• Logging of the incident
8.5 HUMIDIFIER 5000
8.5.1 Humidifier overview
As shown in Figs. 6A and 6B, a humidifier 5000 comprising a water reservoir 5110
and a heating plate 5120 may be provided and configured to couple directly or indirectly with a
PAP device 4000. The water reservoir 5110 is configured to hold a supply of water 5300 that is
heated by the heater plate 5120. The water reservoir 5110 may hold a given, maximum volume of
liquid (e.g. water), typically several hundred millilitres. The water reservoir 5110 is arranged to
receive a flow of breathable gas from the PAP device 4000 through an air inlet and to add humidity
to the breathable gas. The humidified breathable gas exits the humidifier via an outlet for delivery
to a patient interface (not shown) via an air delivery conduit 4170. The air delivery conduit may
include a heated air delivery conduit 4172.
One or more transducers or sensors 5270, such as a temperature sensor, a relative
humidity sensor, an absolute humidity sensor, a flow sensor or other such sensors may be present
at one or more locations along the air path to measure the temperature, relative humidity, absolute
humidity or flow rate at different locations to assist in controlling the humidifier and an optional
heated air delivery conduit 4172. For example the heater plate 5120 may comprise a temperature
sensor to measure the temperature of the heating plate. The one or more transducers or sensors
5270 may also be located external to the air path to measure the ambient conditions such as ambient
temperature, ambient relative humidity and/or ambient absolute humidity.
A heated air delivery conduit 4172 may comprise a heating element 4173 within or
around the heated air delivery conduit 4172. For example wires may be positioned between the
film and supporting ribs of a heated tube. The heated air delivery conduit 4172 may also comprise
one or more transducers or sensors 5270 as described above.
8.6 GLOSSARY
For the purposes of the present technology disclosure, in certain forms of the present
technology, one or more of the following definitions may apply. In other forms of the present
technology, alternative definitions may apply.
Air: In certain forms of the present technology, air supplied to a patient may be
atmospheric air, and in other forms of the present technology atmospheric air may be supplemented
with oxygen.
Continuous Positive Airway Pressure (CPAP): CPAP treatment will be taken to mean
the application of a supply of air or breathable gas to the entrance to the airways at a pressure that
is continuously positive with respect to atmosphere, and preferably approximately constant through
a respiratory cycle of a patient. In some forms, the pressure at the entrance to the airways will vary
by a few centimeters of water within a single respiratory cycle, for example being higher during
inhalation and lower during exhalation. In some forms, the pressure at the entrance to the airways
will be slightly higher during exhalation, and slightly lower during inhalation. In some forms, the
pressure will vary between different respiratory cycles of the patient, for example being increased
in response to detection of indications of partial upper airway obstruction, and decreased in the
absence of indications of partial upper airway obstruction.
Controller: A device, or portion of a device that adjusts an output based on an input.
For example one form of controller has a variable that is under control- the control variable- that
constitutes the input to the device. The output of the device is a function of the current value of the
control variable, and a set point for the variable. A servo-ventilator may include a controller that
has ventilation as an input, a target ventilation as the set point, and level of pressure support as an
output. Other forms of input may be one or more of oxygen saturation (SaO ), partial pressure of
carbon dioxide (PCO ), movement, a signal from a photoplethysmogram, and peak flow. The set
point of the controller may be one or more of fixed, variable or learned. For example, the set point
in a ventilator may be a long term average of the measured ventilation of a patient. Another
ventilator may have a ventilation set point that changes with time. A pressure controller may be
configured to control a blower or pump to deliver air at a particular pressure.
Therapy: Therapy in the present context may be one or more of positive pressure
therapy, oxygen therapy, carbon dioxide therapy, control of dead space, and the administration of
a drug.
Transducers: A device for converting one form of energy or signal into another. A
transducer may be a sensor or detector for converting mechanical energy (such as movement) into
an electrical signal. Examples of transducers include pressure sensors, flow sensors, carbon dioxide
(CO ) sensors, oxygen (O ) sensors, effort sensors, movement sensors, noise sensors, a
plethysmograph, and cameras.
Volute: The casing of the centrifugal pump that receives the air being pumped by the
impeller, slowing down the flow rate of air and increasing the pressure. The cross-section of the
volute increases in area towards the discharge port.
Apnea: Preferably, apnea will be said to have occurred when flow falls below a
predetermined threshold for a duration, e.g. 10 seconds. An obstructive apnea will be said to have
occurred when, despite patient effort, some obstruction of the airway does not allow air to flow. A
central apnea will be said to have occurred when an apnea is detected that is due to a reduction in
breathing effort, or the absence of breathing effort.
Breathing rate: The rate of spontaneous respiration of a patient, usually measured in
breaths per minute.
Effort (breathing): Preferably breathing effort will be said to be the work done by a
spontaneously breathing person attempting to breathe.
Expiratory portion of a breathing cycle: The period from the start of expiratory flow
to the start of inspiratory flow.
Flow limitation: Preferably, flow limitation will be taken to be the state of affairs in a
patient's respiration where an increase in effort by the patient does not give rise to a corresponding
increase in flow. Where flow limitation occurs during an inspiratory portion of the breathing cycle
it may be described as inspiratory flow limitation. Where flow limitation occurs during an
expiratory portion of the breathing cycle it may be described as expiratory flow limitation.
Hypopnea: Preferably, a hypopnea will be taken to be a reduction in flow, but not a
cessation of flow. In one form, a hypopnea may be said to have occurred when there is a reduction
in flow below a threshold for a duration. In one form in adults, the following either of the following
may be regarded as being hypopneas:
(i) a 30% reduction in patient breathing for at least 10 seconds plus an associated 4%
desaturation; or
(ii) a reduction in patient breathing (but less than 50%) for at least 10 seconds, with an
associated desaturation of at least 3% or an arousal.
Patency (airway): The degree of the airway being open, or the extent to which the
airway is open. A patent airway is open. Airway patency may be quantified, for example with a
value of one (1) being patent, and a value of zero (0), being closed.
Positive End-Expiratory Pressure (PEEP): The pressure above atmosphere in the lungs
that exists at the end of expiration.
Peak flow (Qpeak): The maximum value of flow during the inspiratory portion of the
respiratory flow waveform.
Respiratory flow, airflow, patient airflow, respiratory airflow (Qr): These synonymous
terms may be understood to refer to the PAP device’s estimate of respiratory airflow, as opposed
to “true respiratory flow” or “true respiratory airflow”, which is the actual respiratory flow
experienced by the patient, usually expressed in litres per minute.
Upper airway obstruction (UAO): includes both partial and total upper airway
obstruction. This may be associated with a state of flow limitation, in which the level of flow
increases only slightly or may even decrease as the pressure difference across the upper airway
increases (Starling resistor behaviour).
Ventilation (Vent): A measure of the total amount of gas being exchanged by the
patient’s respiratory system, including both inspiratory and expiratory flow, per unit time. When
expressed as a volume per minute, this quantity is often referred to as “minute ventilation”. Minute
ventilation is sometimes given simply as a volume, understood to be the volume per minute.
Flow rate: The instantaneous volume (or mass) of air delivered per unit time. While
flow rate and ventilation have the same dimensions of volume or mass per unit time, flow rate is
measured over a much shorter period of time. Flow may be nominally positive for the inspiratory
portion of a breathing cycle of a patient, and hence negative for the expiratory portion of the
breathing cycle of a patient. In some cases, a reference to flow rate will be a reference to a scalar
quantity, namely a quantity having magnitude only. In other cases, a reference to flow rate will be
a reference to a vector quantity, namely a quantity having both magnitude and direction. Flow will
be given the symbol Q. Total flow, Qt, is the flow of air leaving the PAP device. Vent flow, Qv, is
the flow of air leaving a vent to allow washout of exhaled gases. Leak flow, Ql, is the flow rate of
unintentional leak from a patient interface system. Respiratory flow, Qr, is the flow of air that is
received into the patient's respiratory system.
Leak: Preferably, the word leak will be taken to be a flow of air to the ambient. Leak
may be intentional, for example to allow for the washout of exhaled CO . Leak may be
unintentional, for example, as the result of an incomplete seal between a mask and a patient's face.
Pressure: Force per unit area. Pressure may be measured in a range of units, including
cmH O, g-f/cm , hectopascal. 1cmH O is equal to 1 g-f/cm and is approximately 0.98 hectopascal.
In this specification, unless otherwise stated, pressure is given in units of cmH O. For nasal CPAP
treatment of OSA, a reference to treatment pressure is a reference to a pressure in the range of
about 4-20 cmH O, or about 4-30 cmH O. The pressure in the patient interface is given the symbol
Sound Power: The energy per unit time carried by a sound wave. The sound power is
proportional to the square of sound pressure multiplied by the area of the wavefront. Sound power
is usually given in decibels SWL, that is, decibels relative to a reference power, normally taken as
watt.
Sound Pressure: The local deviation from ambient pressure at a given time instant as
a result of a sound wave travelling through a medium. Sound power is usually given in decibels
SPL, that is, decibels relative to a reference power, normally taken as 20 × 10 pascal (Pa),
considered the threshold of human hearing.
8.7 OTHER REMARKS
A portion of the disclosure of this patent document contains material which is subject
to copyright protection. The copyright owner has no objection to the facsimile reproduction by
anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark
Office patent file or records, but otherwise reserves all copyright rights whatsoever.
Unless the context clearly dictates otherwise and where a range of values is provided,
it is understood that each intervening value, to the tenth of the unit of the lower limit, between the
upper and lower limit of that range, and any other stated or intervening value in that stated range
is encompassed within the technology. The upper and lower limits of these intervening ranges,
which may be independently included in the intervening ranges, are also encompassed within the
technology, subject to any specifically excluded limit in the stated range. Where the stated range
includes one or both of the limits, ranges excluding either or both of those included limits are also
included in the technology.
Furthermore, where a value or values are stated herein as being implemented as part of
the technology, it is understood that such values may be approximated, unless otherwise stated,
and such values may be utilized to any suitable significant digit to the extent that a practical
technical implementation may permit or require it.
Unless defined otherwise, all technical and scientific terms used herein have the same
meaning as commonly understood by one of ordinary skill in the art to which this technology
belongs. Although any methods and materials similar or equivalent to those described herein can
also be used in the practice or testing of the present technology, a limited number of the exemplary
methods and materials are described herein.
When a particular material is identified as being preferably used to construct a
component, obvious alternative materials with similar properties may be used as a substitute.
Furthermore, unless specified to the contrary, any and all components herein described are
understood to be capable of being manufactured and, as such, may be manufactured together or
separately.
It must be noted that as used herein and in the appended claims, the singular forms "a",
"an", and "the" include their plural equivalents, unless the context clearly dictates otherwise.
All publications mentioned herein are incorporated by reference to disclose and
describe the methods and/or materials which are the subject of those publications. The publications
discussed herein are provided solely for their disclosure prior to the filing date of the present
application. Nothing herein is to be construed as an admission that the present technology is not
entitled to antedate such publication by virtue of prior invention. Further, the dates of publication
provided may be different from the actual publication dates, which may need to be independently
confirmed.
Moreover, in interpreting the disclosure, all terms should be interpreted in the broadest
reasonable manner consistent with the context. In particular, the terms "comprises" and
"comprising" should be interpreted as referring to elements, components, or steps in a non-
exclusive manner, indicating that the referenced elements, components, or steps may be present,
or utilized, or combined with other elements, components, or steps that are not expressly
referenced.
The subject headings used in the detailed description are included only for the ease of
reference of the reader and should not be used to limit the subject matter found throughout the
disclosure or the claims. The subject headings should not be used in construing the scope of the
claims or the claim limitations.
Although the technology herein has been described with reference to particular
embodiments, it is to be understood that these embodiments are merely illustrative of the principles
and applications of the technology. In some instances, the terminology and symbols may imply
specific details that are not required to practice the technology. For example, although the terms
"first" and "second" may be used, unless otherwise specified, they are not intended to indicate any
order but may be utilised to distinguish between distinct elements. Furthermore, although process
steps in the methodologies may be described or illustrated in an order, such an ordering is not
required. Those skilled in the art will recognize that such ordering may be modified and/or aspects
thereof may be conducted concurrently or even synchronously.
Further example versions of the technology may be considered in the following
descriptive paragraphs:
Example 1. A poly-phase switched reluctance motor assembly comprising:
a stator assembly including a plurality of coils and a stator with a central bore, and
a rotor assembly having a plurality of poles, the rotor assembly being arranged within
the central bore of the stator assembly and configured to rotate therein,
wherein the plurality of coils are configured in a distributed winding configuration,
wherein the stator includes a plurality of projecting stator teeth forming a plurality of
stator slots therebetween, and
wherein a total number of stator slots is a multiple of number of phases and number of
rotor poles of the motor.
Example 2. The poly-phase switched reluctance motor assembly of Example 1
wherein each of the plurality of stator slots comprises a coil segment from one of the plurality of
coils.
Example 3. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-2, wherein the total number of stator slots further comprises a multiple of
a winding distribution parameter, such that the total number of stator slots satisfies an equation
consisting of:
Total number of stator slots = number of phases X number of rotor poles X winding
distribution parameter.
Example 4. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-3, wherein the plurality of coils includes a coil group for each phase of the
poly-phase switched reluctance motor and each of the coils in a coil group includes a pair of coil
segments, the coil segments for each coil group are uniformly distributed between the stator slots.
Example 5. The poly-phase switched reluctance motor assembly according to
Example 4, wherein each coil group comprises at least one coil.
Example 6. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-5, including at least three motor phases and wherein in use two motor
phases are energized and at least one phase is non-energized during a conduction period.
Example 7. The poly-phase switched reluctance motor assembly according to
Example 6, wherein one of the two energized phases is switched off to a non-energized state and
one of the non-energized phases is switched on to an energized state during each commutation
period.
Example 8. The poly-phase switched reluctance motor assembly according to
any one of Examples 6 or 7, wherein one of the two energized phases is provided with a positive
direction current and the other of the two energized phases is provided with a negative direction
current.
Example 9. The poly-phase switched reluctance motor assembly according to
Example 8, wherein each phase of the motor is energized with a current value during at least two
consecutive conduction periods.
Example 10. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-9, having an inductance ratio of less than 3.
Example 11. The poly-phase switched reluctance motor assembly according to
Example 10, wherein the inductance ratio is between 2 and 2.5.
Example 12. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-11, wherein the stator has an outer diameter less than 50 mm.
Example 13. The poly-phase switched reluctance motor assembly according to
Example 12, wherein the stator has an outer diameter less than or equal to 45 mm.
Example 14. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-13, wherein width of each rotor pole is wider than width of one of the
plurality of stator teeth.
Example 15. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-14, wherein the distributed winding configuration comprises a plurality of
phases with at least one phase of the plurality of phases comprising a plurality of coil winding
groups.
Example 16. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-15 wherein each rotor pole width is equal.
Example 17. The poly-phase switched reluctance motor assembly according to
any one of Examples 1-16 wherein each stator slot width is equal.
Example 18. The poly-phase switched reluctance motor assembly of any one of
Examples 1-17 wherein the stator assembly and rotor assembly are configured to have a difference
between a stator central angle and a rotor central angle in a difference range of 5 to 30 degrees.
Example 19. The poly-phase switched reluctance motor assembly of Example 18
wherein the difference between a stator central angle and a rotor central angle is about 27 degrees.
Example 20. The poly-phase switched reluctance motor assembly of any one of
Examples 1-19 wherein each of the stator teeth comprises teeth tips.
Example 21. A stator assembly for a poly-phase switched reluctance motor
comprising
a plurality of stator teeth separated by stator slots and surrounding a central bore,
a plurality of coils that are configured in a distributed winding configuration, the
plurality of coils includes a coil group for each phase of the poly-phased switched reluctance motor,
wherein the central bore is configured to receive a rotor assembly having a plurality of
poles and a total number of stator slots is a multiple of number of phases and number of rotor poles
of the motor.
Example 22. The stator assembly according to Example 21, wherein each of the
stator slots comprises a coil segment of one of the coils of the plurality of coils.
Example 23. The stator assembly according to any one of Examples 21-22,
wherein each coil group comprises at least one coil.
Example 24. The stator assembly according to any one of Examples 21-23,
wherein a width of each of the stator teeth of the plurality of stator teeth is less than a width of a
rotor pole.
Example 25. The stator assembly according to any one of Examples 21-24,
wherein the distributed winding configuration comprises a plurality of phases with at least one
phase of the plurality of phases comprising a plurality of coil winding groups.
Example 26. The stator assembly according to any one of Examples 21-25
wherein rotor poles of the received rotor assembly have widths that are equal.
Example 27. The stator assembly according to any one of Examples 21-26
wherein each stator tooth width is equal.
Example 28. The stator assembly according to any one of Examples 21-27,
wherein the total number of stator slots comprises a further multiple of a winding distribution
parameter such that the total number of stator slots satisfies an equation consisting of:
Total number of stator slots = number of phases X number of rotor poles X winding
distribution parameter.
Example 29. The stator assembly according to any one of Examples 21-28,
wherein each of the coil segments for a coil group are uniformly distributed between the stator
slots.
Example 30. The stator assembly according to any one of Examples 21-29, having
an inductance ratio of less than 3.
Example 31. The stator assembly according to Example 30, wherein the
inductance ratio is between 2 and 2.5.
Example 32. The stator assembly according to any one of Examples 21-31,
wherein the stator has an outer diameter less than 50 mm.
Example 33. The stator assembly according to Example 32, wherein the stator has
an outer diameter less than or equal to 45 mm.
Example 34. The stator assembly of any one of Examples 21-33 wherein the stator
assembly and rotor assembly are configured to have a difference between a stator central angle and
a rotor central angle in a difference range of 5 to 30 degrees.
Example 35. The stator assembly of Example 34 wherein the difference between
the stator central angle and the rotor central angle is about 27 degrees.
Example 36. The stator assembly of any one of Examples 21-35 wherein each of the
stator teeth comprises teeth tips.
Example 37. A positive airway pressure device comprising a poly-phase switched
reluctance motor according to any one of Examples 1-20 configured to provide a supply of
pressurized breathable gas.
Example 38. A system for treating a respiratory disorder comprising:
a therapy device comprising a poly-phase switched reluctance motor according to any
one of Examples 1-20 configured to provide a supply of pressurized breathable gas;
an air delivery conduit; and
a patient interface configured to receive the supply of pressurized gas from the therapy
device via the air delivery conduit and deliver the supply of pressurized gas to a patient.
Example 39. The system according to Example 38 further comprising a
humidifier configured to humidify the supply of pressurized gas.
Example 40. A method of controlling a switched reluctance motor, the switched
reluctance motor comprising at least three phases, the method comprising:
during each conduction period energizing a first phase with a negative direction
current, energizing a second phase with a positive current and having at least one non-energized
phase; and
during each commutation period switching off one of the first phase or the second
phase to a non-energized state and switching on one of the non-energized phases to an energized
state with a same direction current as the first or second phase that was switched off.
Example 41. The method according to Example 40, wherein the switched
reluctance motor includes a distributed winding configuration.
Example 42. The method of any one of Examples 40-41 wherein the switched
reluctance motor has a total number of stator slots that is a multiple of number of phases and
number of rotor poles.
Example 43. The method of Example 42 wherein the total number of stator slots
further comprises a multiple of a winding distribution parameter.
Example 44. The method of any one of Examples 40-43 wherein the switched
reluctance motor has a stator assembly and rotor assembly configured to have a difference between
a stator central angle and a rotor central angle in a difference range of 5 to 30 degrees.
Example 45. The method of Example 44 wherein the difference between the stator
central angle and the rotor central angle is about 27 degrees.
Example 46. The method of any one of Examples 40-45 wherein the switched
reluctance motor has a plurality of stator teeth, each comprising teeth tips.
Example 47. The method of any one of Examples 40-46 wherein the switched
reluctance motor has only three phases.
Example 48. The method of any one of Examples 40-47 wherein the switched
reluctance motor is a component of a therapy device configured to supply pressurized gas.
It is therefore to be understood that numerous modifications may be made to the
illustrative embodiments and that other arrangements may be devised without departing from the
spirit and scope of the technology.
Claims (29)
1. A poly-phase switched reluctance motor assembly comprising: a stator assembly including a plurality of coils and a stator with a central bore, and a rotor assembly having a plurality of rotor poles, the rotor assembly being arranged within the central bore of the stator assembly and configured to rotate therein, wherein the plurality of coils are configured in a winding configuration, wherein the stator includes a plurality of projecting stator teeth forming a plurality of stator slots therebetween, wherein a sum of a width of each stator tooth of the plurality of stator teeth and each width of gaps adjacent to the stator tooth is equal to a width of each rotor pole of the plurality of rotor poles, wherein the poly-phase switched reluctance motor assembly includes at least three phases, and wherein the poly-phase switched reluctance motor assembly is configured with a controller to apply direct current to each of at least two of the phases, wherein the direct current applied to one of the at least two of the phases is a positive direction current and the direct current applied to the other of the at least two of the phases is a negative direction current.
2. The poly-phase switched reluctance motor assembly of claim 1, wherein each of the plurality of stator slots comprises a coil segment from one of the plurality of coils.
3. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 2, wherein the total number of stator slots further comprises a multiple of a winding distribution parameter, such that the total number of stator slots satisfies an equation consisting Total number of stator slots = number of phases X number of rotor poles X winding distribution parameter.
4. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 3, wherein in use two motor phases are energized and at least one phase is non-energized during a conduction period.
5. The poly-phase switched reluctance motor assembly according to claim 4, wherein one of the two energized phases is switched off to a non-energized state and one of the non- energized phases is switched on to an energized state during each commutation period.
6. The poly-phase switched reluctance motor assembly according to claim 4 or 5, wherein each phase of the motor is energized with a current value during at least two consecutive conduction periods.
7. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 6, having an inductance ratio of less than 3.
8. The poly-phase switched reluctance motor assembly according to claim 7, wherein the inductance ratio is between 2 and 2.5.
9. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 8, wherein the stator has an outer diameter less than 50 mm.
10. The poly-phase switched reluctance motor assembly according to claim 9, wherein the stator has an outer diameter less than or equal to 45 mm.
11. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 10, wherein width of each rotor pole is wider than width of one of the plurality of stator teeth.
12. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 11, wherein each rotor pole width is equal.
13. The poly-phase switched reluctance motor assembly according to any one of claims 1 to 12, wherein each stator tooth width is equal.
14. The poly-phase switched reluctance motor assembly of any one of claims 1 to 13, wherein each of the stator teeth comprises teeth tips.
15. A stator assembly for a poly-phase switched reluctance motor comprising: a plurality of stator teeth separated by stator slots and surrounding a central bore, a plurality of coils that are configured in a winding configuration, the plurality of coils includes a coil group for each phase of the poly-phased switched reluctance motor, wherein the central bore is configured to receive a rotor assembly having a plurality of rotor poles, wherein, when the stator assembly is configured with the rotor assembly for use as the poly-phase switched reluctance motor, a sum of a width of each stator tooth of the plurality of stator teeth and each width of gaps adjacent to the stator tooth is equal to a width of each rotor pole of the plurality of rotor poles, wherein the stator assembly includes at least three phases, and wherein, when the stator assembly is configured with the rotor assembly and a controller for use as the poly-phase switched reluctance motor, the poly-phase switched reluctance motor is configured to operate with the at least three phases such that direct current is applied to each of at least two of the phases, wherein the direct current applied to one of the at least two of the phases is a positive direction current and the direct current applied to the other of the at least two of the phases is a negative direction current.
16. The stator assembly according to claim 15, wherein each of the stator slots comprises a coil segment of one of the coils of the plurality of coils.
17. The stator assembly according to any one of claims 15 or 16, wherein each coil group comprises at least one coil.
18. The stator assembly according to any one of claims 15 to 17, wherein a width of each of the stator teeth of the plurality of stator teeth is less than a width of a rotor pole.
19. The stator assembly according to any one of claims 15 to 18, wherein the rotor poles of the received rotor assembly have widths that are equal.
20. The stator assembly according to any one of claims 15 to 19, wherein each stator tooth width is equal.
21. The stator assembly according to any one of claims 15 to 20, wherein the total number of stator slots comprises a further multiple of a winding distribution parameter such that the total number of stator slots satisfies an equation consisting of: Total number of stator slots = number of phases X number of rotor poles X winding distribution parameter.
22. The stator assembly according to any one of claims 15 to 21, having an inductance ratio of less than 3.
23. The stator assembly according to claim 22, wherein the inductance ratio is between 2 and 2.5.
24. The stator assembly according to any one of claims 15 to 23, wherein the stator has an outer diameter less than 50 mm.
25. The stator assembly according to claim 24, wherein the stator has an outer diameter less than or equal to 45 mm.
26. The stator assembly of any one of claims 15 to 25, wherein each of the stator teeth comprises teeth tips.
27. A positive airway pressure device comprising a poly-phase switched reluctance motor according to any one of claims 1 to 14 configured to provide a supply of pressurized breathable gas.
28. A system for treating a respiratory disorder comprising: a therapy device comprising a poly-phase switched reluctance motor according to any one of claims 1 to 14 configured to provide a supply of pressurized breathable gas; an air delivery conduit; and a patient interface configured to receive the supply of pressurized gas from the therapy device via the air delivery conduit and deliver the supply of pressurized gas to a patient.
29. The system according to claim 28, further comprising a humidifier configured to humidify the supply of pressurized gas. 111,11,111:1MIS k....1111$11.1411110110.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US201461928547P | 2014-01-17 | 2014-01-17 | |
US61/928,547 | 2014-01-17 | ||
NZ72104715 | 2015-01-16 |
Publications (2)
Publication Number | Publication Date |
---|---|
NZ760787A NZ760787A (en) | 2021-08-27 |
NZ760787B2 true NZ760787B2 (en) | 2021-11-30 |
Family
ID=
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US11716002B2 (en) | Switched reluctance motor | |
US11207480B2 (en) | Induction motor control | |
US7448383B2 (en) | Air assistance apparatus providing fast rise and fall of pressure within one patient's breath | |
EP2819730B1 (en) | Continuous positive airway pressure (cpap) therapy using measurements of speed and pressure | |
EP1884256A1 (en) | Pressure targeted ventilator using an oscillating pump | |
JP6396892B2 (en) | Pressure control for breathing comfort | |
WO2003075989A2 (en) | An air assistance apparatus providing fast rise and fall of pressure within one patient's breath | |
EP2819729B1 (en) | Dual pressure sensor continuous positive airway pressure (cpap) therapy | |
CN104379204A (en) | System, apparatus and methods for supplying gases | |
US11684735B2 (en) | Respiratory apparatus with multiple power supplies | |
US9642976B2 (en) | Systems and methods for intra-pulmonary percussive ventilation integrated in a ventilator | |
WO2013027151A1 (en) | Method and apparatus for controlling a ventilation therapy device | |
NZ760787B2 (en) | Switched reluctance motor | |
NZ760787A (en) | Switched reluctance motor | |
US10744295B2 (en) | Respiratory therapy apparatus | |
Tourgoli et al. | Dynamic modeling and simulation of Continuous Positive Airway Pressure device |