CA1163314A - Hall element circuit for electronically commutating motor - Google Patents
Hall element circuit for electronically commutating motorInfo
- Publication number
- CA1163314A CA1163314A CA000365916A CA365916A CA1163314A CA 1163314 A CA1163314 A CA 1163314A CA 000365916 A CA000365916 A CA 000365916A CA 365916 A CA365916 A CA 365916A CA 1163314 A CA1163314 A CA 1163314A
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- Canada
- Prior art keywords
- signals
- magneto
- sensitive elements
- resistor
- signal
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K29/00—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices
- H02K29/06—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices
- H02K29/08—Motors or generators having non-mechanical commutating devices, e.g. discharge tubes or semiconductor devices with position sensing devices using magnetic effect devices, e.g. Hall-plates, magneto-resistors
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Motors That Do Not Use Commutators (AREA)
Abstract
PHN.9644 14 5.9.80 "ABSTRACT":
"Electronically commutating motor".
An electric machine with electronic commutation, in which two Hall elements can be arranged at a tangential angle which is smaller than the phase difference ?
which. is necessary between the energizing signals in order to obtain a correct energization of the motor, in that the energizing circuit is provided with a combining circuit for linearly combining the signals obtained from the Hall elements in order to obtain signals with a phase difference equal to ?.
"Electronically commutating motor".
An electric machine with electronic commutation, in which two Hall elements can be arranged at a tangential angle which is smaller than the phase difference ?
which. is necessary between the energizing signals in order to obtain a correct energization of the motor, in that the energizing circuit is provided with a combining circuit for linearly combining the signals obtained from the Hall elements in order to obtain signals with a phase difference equal to ?.
Description
-1 1~33~
PHN. 9644 The inven*ion.relates to an electric machine with electronic commutation, having a rotor which at least partly consist of:a permanent-magne-t material, which rotor co-operates with at least two stationarily arranged stator coils, which machine is equipped with at least two magneto-sensiti~e elements arranged on a common substrate, specifically Hall:elements, for supplying signals which vary substantially.sinusoidally with the rotor position in order to energize the stator coils as a 10 function of the rotor position.via an energizing circuit, the magneto-sensiti~e elements being arranged at a tangential angle re:lative to the rotor axis, which angle is smaller than the phase difference y which is necessary b.etween the energizing signa.ls :Eor the stator coils in order to obtain a correct energization of said stator coils.
Such a machine is known from Applicant's Canadian Patent 1,051,969.- issued April 3, 1979 (PHN.7940).
In conv:entional electronically commutating machines the magneto-sensi*ive elements are arranged at an 20. angle y corresponding to.the phase angle of the machine, i.e. electrically at 12~ in the case of a three-phase machine and at 90 in the c~se of a two or four-phase machine. In.accordance with the.said Patent Application by the draw~acks of th:is,.:such.as mounting and intercon-necting two separate parts,.are overcome moun.ting the twomagneto-sensiti~e elements.together on one substrate and ha~ing this co-operate with a disk which is mounted on the rvtor.shaft and is. pro~ided.~ith two concentric magneti-cally coded tracks. ~ disa.d~antage of this is that , since said tracks should.be arranged near each other, there is .a substantially amount of leakage, so that the Hall elements receive little flux .~
1 1~331~
,;
PHN.9644 2 5,9.80 ..
and should be mounted very closely to the disk~ bu-t so as to ensure a free rotatlon of -the disk. Moreover, such a magnetically-coded disk is highly disadvantageous from an economic point of view.
It is the object of the invention -to provide an electric machine wh:ch does not have this drawback and to this end it is characterized in that -the energizing circuit is provided with a combining circuit for linearly cornbining the signals supplied by at least two magneto-10 sensitive elements, in order to obtain at least two energizing signals having a mutual phase difference which is substantially equal to ~. `
; The invention is based on -the recognition that from -two phase-shifted substantially sinusoidal signals 15 two signals with another phase difference can be derived by linearly combining said signals and that this enables -the magneto-sensi-tive elements to be arranged at compara-tively small tangen-tial angles relative to the ro-tor axis.
A first ~referred ernbodiment of the invention
PHN. 9644 The inven*ion.relates to an electric machine with electronic commutation, having a rotor which at least partly consist of:a permanent-magne-t material, which rotor co-operates with at least two stationarily arranged stator coils, which machine is equipped with at least two magneto-sensiti~e elements arranged on a common substrate, specifically Hall:elements, for supplying signals which vary substantially.sinusoidally with the rotor position in order to energize the stator coils as a 10 function of the rotor position.via an energizing circuit, the magneto-sensiti~e elements being arranged at a tangential angle re:lative to the rotor axis, which angle is smaller than the phase difference y which is necessary b.etween the energizing signa.ls :Eor the stator coils in order to obtain a correct energization of said stator coils.
Such a machine is known from Applicant's Canadian Patent 1,051,969.- issued April 3, 1979 (PHN.7940).
In conv:entional electronically commutating machines the magneto-sensi*ive elements are arranged at an 20. angle y corresponding to.the phase angle of the machine, i.e. electrically at 12~ in the case of a three-phase machine and at 90 in the c~se of a two or four-phase machine. In.accordance with the.said Patent Application by the draw~acks of th:is,.:such.as mounting and intercon-necting two separate parts,.are overcome moun.ting the twomagneto-sensiti~e elements.together on one substrate and ha~ing this co-operate with a disk which is mounted on the rvtor.shaft and is. pro~ided.~ith two concentric magneti-cally coded tracks. ~ disa.d~antage of this is that , since said tracks should.be arranged near each other, there is .a substantially amount of leakage, so that the Hall elements receive little flux .~
1 1~331~
,;
PHN.9644 2 5,9.80 ..
and should be mounted very closely to the disk~ bu-t so as to ensure a free rotatlon of -the disk. Moreover, such a magnetically-coded disk is highly disadvantageous from an economic point of view.
It is the object of the invention -to provide an electric machine wh:ch does not have this drawback and to this end it is characterized in that -the energizing circuit is provided with a combining circuit for linearly cornbining the signals supplied by at least two magneto-10 sensitive elements, in order to obtain at least two energizing signals having a mutual phase difference which is substantially equal to ~. `
; The invention is based on -the recognition that from -two phase-shifted substantially sinusoidal signals 15 two signals with another phase difference can be derived by linearly combining said signals and that this enables -the magneto-sensi-tive elements to be arranged at compara-tively small tangen-tial angles relative to the ro-tor axis.
A first ~referred ernbodiment of the invention
2~ concerns a two-phase or four-phase machine and is characterized in tha-t the combining circuit supplies a signal which is propor-tional to the sum of the signals supplied by the two magneto-sensitive elements and a signal which is proportional to the difference of the 25 signals supplied by the -two magneto-sensitive elements.
This embodiment has the advantage that the phase difference between said combined signals is independent of the -tangen-tial angle at which the two magneto-sensitive elements are arranged.
In general, such a linear combination, which also enables phase differences o-ther than 90 to be realized, may be characterized in that the combining circuit supplies a first signal C, which satisfies -the equation C = ~ ~ KB, and a second signal D, which satisfies -the equa-tion 35 D = ~ - KB, where A is the signal supplied by a first one of -the magneto-sensi-tive elements, B :is the signal supplied by a second one of -the magneto-sensitive elernents, and K is a predetermined cons-tan-t which is such
This embodiment has the advantage that the phase difference between said combined signals is independent of the -tangen-tial angle at which the two magneto-sensitive elements are arranged.
In general, such a linear combination, which also enables phase differences o-ther than 90 to be realized, may be characterized in that the combining circuit supplies a first signal C, which satisfies -the equation C = ~ ~ KB, and a second signal D, which satisfies -the equa-tion 35 D = ~ - KB, where A is the signal supplied by a first one of -the magneto-sensi-tive elements, B :is the signal supplied by a second one of -the magneto-sensitive elernents, and K is a predetermined cons-tan-t which is such
3 3 1 ~
P~N.~64~ 3 5.9.80 that the phase difference be-tween the signals C and D
is eaual to ~.
A drawback of -this combining method may he that in general the amplitudes of the combination signals C
and D are not equal. An embodiment of the machine in accordance with the invention which does not have said drawback may be characterized in that the combining circuit supplies a first signal C, which satisfies the equation C _ A - kB, and a second signal D, which satisfies the equation D = B - kA, where A is the signal supplied by a first one of the magneto-se~i-tive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and k is a predetermined constant which is such that the phase difference between the signals C and D is equal to ~.
A very simple embodiment of the last-mentioned machine may further be charact;erized in that the ener-gizing circuit comprises a first comparator, of which a first input is connec-ted to a first one of -the magneto-sensitive elements, of which an output is connected tothe series connection of a first one of -the stator coils and a first resistor, and of which a second input is connected to the junction between said first stator coil and said firs-t resistor, a second comparator, of Irhich ` 25 a first input is connec-ted to a second one of the magneto-- sensi-tive elements, of which an output is connected to the series connec-tion of a second one of the stator coils and a second resis-tor, and of which a second input is connected to the junction be-tween the second stator coil and said second resistor, and a third resistor, which is included be-tween the junction of the firs-t stator coil and the first resistor and the junction of the second sta-tor coil and the second resistor.
A preferred embodiment of a three-phase machine in accorctance with -the invention may further be character-ized in that the firs-t resistor is a variable resistor.
The invention will now be described in more de-tail with reference to -the drawing, in which t l633~
P~IN. 9644 4 5.9.80 Figure 1 is a ashematic elevation of a three-phase electronically commutating motor which is equippecl with a ~Iall-element in a conventional manner, Figure 2 represents a sectional view of the motor Or ~igure 1 in more detail, Figure 3 shows the arrangement of the ~all elements in accordance with the invention in a motor as shown in Figure 1, ~ igure 4 is a vector diagram to illustrate the use of the invention in a two-phase motor, ~ igure 5 is a vector diagram -to illustrate a first general embodiment of a mo-tor in accordance wi-th the invention, Figure 6 is a vector diagram to illu.strate a preferred ambodiment of a motor in accordance with the i.nven-tion, Figure 7 is a vector diagram to illustrate an alternative o~ the embodiment described with re~erence to Figure 6, 2~ Figure 8 is a circuit for realizing the linear combination described with re~erence to Figure 4, ~igure 9 represents a circuit ~or realizing -the linear combination described with re~erence to Figures 6 and 7, Figure 10 is a vec-tor diagram to il]ustrate the linear combination in the case of a three phase motor, Figure 11 represents a preferred embodiment ~or realizing the combination me-thod descri.bed wi-th reference to Figure 10, and ~igure 12 represents a combination method in accordance with -the invention with -triangular signals.
Figure 1 is a schematic elevation o~ a three-phase electronically commutating motor which is equipped wi-th ~lall elemen-ts in a conventional manner and Figure 2 in a greater detail represents a sectional view o~ the motor o~ Fig~ure 1 -taken on the line II. The motor com-prises a sha~-t 1 on which a bell-shaped rotor housing 2 is secured, which on the inner circumference is provicled l ~63~1~
PHN.9644 5 5.9.80 ;~t~
wi-th an annular permanent magnet ~. The stator body L~
carries a lamination assembly 5 on which three stator coils 6,7 and 8 are arranged. On the stator body L~ a support 9 is mounted on which the Hall elements 10 and 11 are arranged at an angle of 120 , which elemen-ts detect the field o~ the permanent-magnet ring ~ and, via a circuit which is also mounted on said support, energize the s-tator coils 6, 7 and 8 as a function of the rotor position.
Figure 3 illustrates a solution for the arrange-lO ment of the Hall elements 10 and 11 in accordance with the invention in a mo-tor in accordance with Figures 1 and 2. For the sake o~ simplicity only the stator lamination assembly of this motor is shown. The two Hall elements 10 and 11 are arranged closely to each other l5 - at an angle ~ relative to -the rotor axis - so that by means of ~ilm techniques they can be accommodated on one substrate -together with the required electronics or they can even be incorporated in one integrated circuit together with the required electronicsO Nevertheless it is found 20 possible to realize the correct phase differences between the ener~izing signals ~or the stator coils by generating linear combinations of the signals from the Hall elements 10 and 11, provided with said signals are substantially sinusoidal.
This is illustrated in Figure ~ by means o~ -a vector diagram ~or a t~o-phase (or four-phase) motor.
The signals A and B from the Hall elements 10 and 11 respec-tively, the sum C of -these signals A and B and the difference D of saicl signals A and B are represented 30 as vectors in this Figure. It is ~ound that generating the linear combinations:
C = A~B
and D = A-B
yields two signals with a phase clifference o~ 90 .
35 For these combinations, t~is is inclependent of the angle ~ between the Hall elements. In general it is possible to generate any phase difference between the signals C and D by means o~ the li~ear combinations:
~ 16331~
- PHN.9644 6 5.9.80 C _ A~KB
and D = A-EB
where ~ is a constant factor which depends on the angle and the desired phase difference between the signals C and D.
If it is required - for example when the two Hall elements 10 and 11 are disposed symmetrically relative -to the centre between two stator poles, as is shown in Figure 3 - that the vector C is situated exactly between the vectors A and B in view of the correct commutation ins-tants, then it is for example possible to generate the following linear combinations:
C = A+B
D = A-KB
Figure 5 shows such a vector diagram for a phase difference of 120 between the signals C and D.
This diagram is sel~-explana-tory.
In the case of the combination methods described with re~erence -to the vector cliagrams o~ Figures L~ and 5 ,LO the amplitudes of the signals C and D are not equal when the amplitudes of the signals A and B are equal.
When the signals C and D solely switch the stator excitation at their zero passages, this is not a problem.
~oweverJ if the signals C and D are employed as energizing signals for the stator coils, as the case may be after amplification, then i-t may be necessary to amplify the two signals to the same amplitude by adapting the gain factors o~ said ampli~ier~ A combina-tion method which does not have this drawback is described with reference to Figure 6.
Figure 6 represents the vector diagram associated with the following linear combinations:
C = B-KA
D = A-~B
In -the case of this linear combina-tion -the ampli-tudes of -the signals C ancl D are equal i~ the amplitudes of -the signa:Ls A and B are also equal. In the vec-tor diagram ~ ~331`~
PHN.964~ 7 5.9~80 of ~igure 6 the factor K has been selected so tha-t when the vec-tors A and B are situated at -2'~ and ~2'~ respec--tively~ the vectors C and D are situated at ~120 and +2L~o respectively. The third phase-signal E for a three-phase rnotor is obtained in known manner by inverting the sum of the signals C and D (E = -C-D). It is also possible to employ the attenuated sum of the signals A and B.
~ igure 7 represents the vector diagram of an alternative method of realizing the combination described with reference -to ~igure 6 in order ot obtain a three-phase signal. The factor K is then selected so that the vectors C and D are situated at 60 and 300 respectively and the vec-tor ~ = -(C~D) is consequently - situated at -180.
The linear combinations described can simply be realized by means of operational amplifiers, which may be integrated together wi-th the Hall elements 10 and 11.
Figure 8 shows an example of a circuit for realizing the linear combination described with reference to ~igure l~. The circuit comprises a summing amplifier 12 having a gain factor G1~ to which the sign~ls A and B from the Hall elements 10 and 'I 1 are applied. The output signal G1 (A+B) may be applied directly across a stator coil 6' of a two-phase motor. The signals A and B are furthermore applied to a differential amplifier ~ with a gain factor G2. The output signal G2 (A-B) is then 90 out of phase with the output signal G1 (A~B) and may be applied directly to the other stator coil 7'. By a sui-table adjustment of the gain factors G1 and G2 relative to each other -the amplitudes of the two ou-tput signals can be equalized.
The amplitude ratio of the signals G1 (A~B) and G (A-B) is of less significance when these signals are employed as switching signals, ~or e~ample when the outputs of the amplifiers 12 and 17 are connected to the sta-tor coils 6' and 7' via switching -transistors T1 and T2 respectively instead of direc-tly~ as is represented by the dashed connections in ~igure 8.
~ ~16~3~L
PHN.9644 8 5.9.80 By means of the circuit of Figure 8 it is also possible to realize other linear combinations of the signals A ancl B in order to realize phase differences other than 90 between the output signals, employing -the linear combinations discussed with re~erence to Figures 4 and 5. For this purpose the factors K may for example be realized in the amplifiers 12 and 17 for example by means of operational amplifiers known from analogue computing technology~
Figure 9 shows an example of a circuit for reali7ing the linear combinations A KB and B-KA discussed with reference to Figures 6 and 7. It comprises an operational amplifier 18, which amplifies the signal A
by a factor G and the signal B by a factor -KG, so that an output signal G(A-KB) is obtained, which may be applied.
directly to a stator coil 6 of a three-phase motor.
A second operational amplifier 19 amplifies the signal B
by a fac-tor G and the signal A by a factor -KG, so that a signal G(B-KA) - which in the case of a suitable choice of the factor ~ differs 120 in phase with the signal G(A-B) - is obtained, whichmay be applied directly to the coil 7 o~ the three-phase motor. The third phase can be obtained by inverting -the sum of the output signals, which yields -the signal G(1-k~(A+B). This signal - as is shown in Figure 9 - can also be realized by means of a third amplifier 20 having a gain factor (k-1)G, to which the signals A and B are applied. The output signal may then be applied directly to the third stator coil 8.
As is known, a three-phase motor may also be energized by three signals having a phase dif~erence of relative to each other instead of by three signals having a phase difference of 120 rela-tive to each o-ther, if one of the stator coils is energized with opposite polarity or, viewed from the winding sense, from the opposi-te direction~ which in -the diagram of Figure 7 for exarnple means that the vector E is shifted through 180, so -that the vectors C, D anc1 E are situated at 60 ~ ~B33~
PHN.9644 ~ 5 9 oO
relative -to each other. If, as :is illustra-ted by -the vector diagram of Figure 10, two signals C ancl D with a phase difference of 60 are generated by a sui-table choice of the factor K, the third phase E is obtained by taking the difference E = D - C of the signals D and C.
If in the circuit of Figure 9 the factor K is selected so that a phase difference of 60 exists between the output signals o~ amplifiers 18 and 19, the third stator coil 8 may be energized with the third phase E by including it between the outputs of the amplifiers 18 and 19, as is represented by the dashed line in Fi~ure 9. Amplifier 20 may then be dispensed with. Stator coil 7 should then be ellergized (or wound) in a reverse sense in comparison with the situation with the signals at 120 .
l5The linear combinations C = B-XA and D = A-KB
can simply by realized by allowing cross-talk with a factor K to occur between an amplifier for -the signal A
; and an amplifier for -the signal B. This is utilized in the circuit of Figure 11. In this circuit the current ` 20 through the stator coil 6 or 7 is sensed by including a resistor 21 and 22 respectively, both for example having a resistance value Ro. The current through the stator coil 6 or 7 is controlled by an amplifier 23 and 24 respectively, which compared the signals A and B, in -this case a vol-tage, with the voltage across the resistors 21 and 22 respec-tively. The curren-ts through -the coi]s 6 and 7 are -then A/Ro and B/Ro respectively, which when the E~all elements 10 and 11 are arranged in a conven-tional manner (Figure 1) e~hibi-t a phase difference of for e~ample 120 . If a phase difference of 60 is selected, the third sta-tor coil ~
may simply be included between the outputs of the ampli-fiers 23 and 24. However, if -the Hall elements 10 and 11 are arranged at a smaller angle ~ (Figure 3), the phase difference between the currents -through the coils 6 and 7 can still be made 60 (or, if desired, 120 or other phase di~`ferences) by combining -the signals A and B, in the present case very simply by :including a cross-talk ~ 1~33~
PIIN.~644 10 5.9.80 resistor 25 with a resistance value R1 between the junction of the coil 6 ancl resistor 21 and -the junc-tion of coil 7 and resistor 22. Through resistor 21 a current A/Ro flows, through resistor 22 a current B/Ro, and through resistor 25 a current (A-B~R, so that through stator coil 6 a current I6 = P(A KB) flows and through stator coil 7 a current I7 = P(B-KA), where P = (Ro +Rl )/~oR1 and K = ~o/(Ro + R1 ) O By a suitable choice of ~, which can be determined by e~periment, for examp]e by using a variable resistor for -the resistor 25, i-t is again possible toobtain the correct phase difference.
In particular when the signals from the Hall elements are used for switching, instead of for analogue energization (as is for example shown as an alternative in Eigure 8), the waveform of the signals A and B generated by the lIall elements 10 and 11 less critical. This can be demonstra-ted by means of ~igure 12, in which Eigures 12a and 12b represent the signals A and B as triangular voltage waveforms. ~igure 12c represents the sum of said 20 signals A and B and Eigure 12d the difference of said signals A and B. It is found that also in this case the zero passages of the combinations A+B and A-B are shifted through a quartero~ the period of the signals A and B, i.e. through 90, relative to each other~ Other shifts are possible with other combinations.
Especially when the signals from the Hall elements 10 and 11 and the linear combinations thereof are employed as analogue energizing signals for the stator coils, it may occur in practice that the form and/or the streng-th of the magnetization of the permanent-magnet rotor is not suitable -to produce suitable signals in the Hall elements. A sui-table solution is -then to arrange an additional magnetic disk on the ro-tor shaft, with which disk the Hall elements co-operate. The advantage that -the two elements can be arranged near each other is then maintained, whils-t the drawback of the known mo-tor with magnetically-coded disk mentioned in -the introduction does not occur.
P~N.~64~ 3 5.9.80 that the phase difference be-tween the signals C and D
is eaual to ~.
A drawback of -this combining method may he that in general the amplitudes of the combination signals C
and D are not equal. An embodiment of the machine in accordance with the invention which does not have said drawback may be characterized in that the combining circuit supplies a first signal C, which satisfies the equation C _ A - kB, and a second signal D, which satisfies the equation D = B - kA, where A is the signal supplied by a first one of the magneto-se~i-tive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and k is a predetermined constant which is such that the phase difference between the signals C and D is equal to ~.
A very simple embodiment of the last-mentioned machine may further be charact;erized in that the ener-gizing circuit comprises a first comparator, of which a first input is connec-ted to a first one of -the magneto-sensitive elements, of which an output is connected tothe series connection of a first one of -the stator coils and a first resistor, and of which a second input is connected to the junction between said first stator coil and said firs-t resistor, a second comparator, of Irhich ` 25 a first input is connec-ted to a second one of the magneto-- sensi-tive elements, of which an output is connected to the series connec-tion of a second one of the stator coils and a second resis-tor, and of which a second input is connected to the junction be-tween the second stator coil and said second resistor, and a third resistor, which is included be-tween the junction of the firs-t stator coil and the first resistor and the junction of the second sta-tor coil and the second resistor.
A preferred embodiment of a three-phase machine in accorctance with -the invention may further be character-ized in that the firs-t resistor is a variable resistor.
The invention will now be described in more de-tail with reference to -the drawing, in which t l633~
P~IN. 9644 4 5.9.80 Figure 1 is a ashematic elevation of a three-phase electronically commutating motor which is equippecl with a ~Iall-element in a conventional manner, Figure 2 represents a sectional view of the motor Or ~igure 1 in more detail, Figure 3 shows the arrangement of the ~all elements in accordance with the invention in a motor as shown in Figure 1, ~ igure 4 is a vector diagram to illustrate the use of the invention in a two-phase motor, ~ igure 5 is a vector diagram -to illustrate a first general embodiment of a mo-tor in accordance wi-th the invention, Figure 6 is a vector diagram to illu.strate a preferred ambodiment of a motor in accordance with the i.nven-tion, Figure 7 is a vector diagram to illustrate an alternative o~ the embodiment described with re~erence to Figure 6, 2~ Figure 8 is a circuit for realizing the linear combination described with re~erence to Figure 4, ~igure 9 represents a circuit ~or realizing -the linear combination described with re~erence to Figures 6 and 7, Figure 10 is a vec-tor diagram to il]ustrate the linear combination in the case of a three phase motor, Figure 11 represents a preferred embodiment ~or realizing the combination me-thod descri.bed wi-th reference to Figure 10, and ~igure 12 represents a combination method in accordance with -the invention with -triangular signals.
Figure 1 is a schematic elevation o~ a three-phase electronically commutating motor which is equipped wi-th ~lall elemen-ts in a conventional manner and Figure 2 in a greater detail represents a sectional view o~ the motor o~ Fig~ure 1 -taken on the line II. The motor com-prises a sha~-t 1 on which a bell-shaped rotor housing 2 is secured, which on the inner circumference is provicled l ~63~1~
PHN.9644 5 5.9.80 ;~t~
wi-th an annular permanent magnet ~. The stator body L~
carries a lamination assembly 5 on which three stator coils 6,7 and 8 are arranged. On the stator body L~ a support 9 is mounted on which the Hall elements 10 and 11 are arranged at an angle of 120 , which elemen-ts detect the field o~ the permanent-magnet ring ~ and, via a circuit which is also mounted on said support, energize the s-tator coils 6, 7 and 8 as a function of the rotor position.
Figure 3 illustrates a solution for the arrange-lO ment of the Hall elements 10 and 11 in accordance with the invention in a mo-tor in accordance with Figures 1 and 2. For the sake o~ simplicity only the stator lamination assembly of this motor is shown. The two Hall elements 10 and 11 are arranged closely to each other l5 - at an angle ~ relative to -the rotor axis - so that by means of ~ilm techniques they can be accommodated on one substrate -together with the required electronics or they can even be incorporated in one integrated circuit together with the required electronicsO Nevertheless it is found 20 possible to realize the correct phase differences between the ener~izing signals ~or the stator coils by generating linear combinations of the signals from the Hall elements 10 and 11, provided with said signals are substantially sinusoidal.
This is illustrated in Figure ~ by means o~ -a vector diagram ~or a t~o-phase (or four-phase) motor.
The signals A and B from the Hall elements 10 and 11 respec-tively, the sum C of -these signals A and B and the difference D of saicl signals A and B are represented 30 as vectors in this Figure. It is ~ound that generating the linear combinations:
C = A~B
and D = A-B
yields two signals with a phase clifference o~ 90 .
35 For these combinations, t~is is inclependent of the angle ~ between the Hall elements. In general it is possible to generate any phase difference between the signals C and D by means o~ the li~ear combinations:
~ 16331~
- PHN.9644 6 5.9.80 C _ A~KB
and D = A-EB
where ~ is a constant factor which depends on the angle and the desired phase difference between the signals C and D.
If it is required - for example when the two Hall elements 10 and 11 are disposed symmetrically relative -to the centre between two stator poles, as is shown in Figure 3 - that the vector C is situated exactly between the vectors A and B in view of the correct commutation ins-tants, then it is for example possible to generate the following linear combinations:
C = A+B
D = A-KB
Figure 5 shows such a vector diagram for a phase difference of 120 between the signals C and D.
This diagram is sel~-explana-tory.
In the case of the combination methods described with re~erence -to the vector cliagrams o~ Figures L~ and 5 ,LO the amplitudes of the signals C and D are not equal when the amplitudes of the signals A and B are equal.
When the signals C and D solely switch the stator excitation at their zero passages, this is not a problem.
~oweverJ if the signals C and D are employed as energizing signals for the stator coils, as the case may be after amplification, then i-t may be necessary to amplify the two signals to the same amplitude by adapting the gain factors o~ said ampli~ier~ A combina-tion method which does not have this drawback is described with reference to Figure 6.
Figure 6 represents the vector diagram associated with the following linear combinations:
C = B-KA
D = A-~B
In -the case of this linear combina-tion -the ampli-tudes of -the signals C ancl D are equal i~ the amplitudes of -the signa:Ls A and B are also equal. In the vec-tor diagram ~ ~331`~
PHN.964~ 7 5.9~80 of ~igure 6 the factor K has been selected so tha-t when the vec-tors A and B are situated at -2'~ and ~2'~ respec--tively~ the vectors C and D are situated at ~120 and +2L~o respectively. The third phase-signal E for a three-phase rnotor is obtained in known manner by inverting the sum of the signals C and D (E = -C-D). It is also possible to employ the attenuated sum of the signals A and B.
~ igure 7 represents the vector diagram of an alternative method of realizing the combination described with reference -to ~igure 6 in order ot obtain a three-phase signal. The factor K is then selected so that the vectors C and D are situated at 60 and 300 respectively and the vec-tor ~ = -(C~D) is consequently - situated at -180.
The linear combinations described can simply be realized by means of operational amplifiers, which may be integrated together wi-th the Hall elements 10 and 11.
Figure 8 shows an example of a circuit for realizing the linear combination described with reference to ~igure l~. The circuit comprises a summing amplifier 12 having a gain factor G1~ to which the sign~ls A and B from the Hall elements 10 and 'I 1 are applied. The output signal G1 (A+B) may be applied directly across a stator coil 6' of a two-phase motor. The signals A and B are furthermore applied to a differential amplifier ~ with a gain factor G2. The output signal G2 (A-B) is then 90 out of phase with the output signal G1 (A~B) and may be applied directly to the other stator coil 7'. By a sui-table adjustment of the gain factors G1 and G2 relative to each other -the amplitudes of the two ou-tput signals can be equalized.
The amplitude ratio of the signals G1 (A~B) and G (A-B) is of less significance when these signals are employed as switching signals, ~or e~ample when the outputs of the amplifiers 12 and 17 are connected to the sta-tor coils 6' and 7' via switching -transistors T1 and T2 respectively instead of direc-tly~ as is represented by the dashed connections in ~igure 8.
~ ~16~3~L
PHN.9644 8 5.9.80 By means of the circuit of Figure 8 it is also possible to realize other linear combinations of the signals A ancl B in order to realize phase differences other than 90 between the output signals, employing -the linear combinations discussed with re~erence to Figures 4 and 5. For this purpose the factors K may for example be realized in the amplifiers 12 and 17 for example by means of operational amplifiers known from analogue computing technology~
Figure 9 shows an example of a circuit for reali7ing the linear combinations A KB and B-KA discussed with reference to Figures 6 and 7. It comprises an operational amplifier 18, which amplifies the signal A
by a factor G and the signal B by a factor -KG, so that an output signal G(A-KB) is obtained, which may be applied.
directly to a stator coil 6 of a three-phase motor.
A second operational amplifier 19 amplifies the signal B
by a fac-tor G and the signal A by a factor -KG, so that a signal G(B-KA) - which in the case of a suitable choice of the factor ~ differs 120 in phase with the signal G(A-B) - is obtained, whichmay be applied directly to the coil 7 o~ the three-phase motor. The third phase can be obtained by inverting -the sum of the output signals, which yields -the signal G(1-k~(A+B). This signal - as is shown in Figure 9 - can also be realized by means of a third amplifier 20 having a gain factor (k-1)G, to which the signals A and B are applied. The output signal may then be applied directly to the third stator coil 8.
As is known, a three-phase motor may also be energized by three signals having a phase dif~erence of relative to each other instead of by three signals having a phase difference of 120 rela-tive to each o-ther, if one of the stator coils is energized with opposite polarity or, viewed from the winding sense, from the opposi-te direction~ which in -the diagram of Figure 7 for exarnple means that the vector E is shifted through 180, so -that the vectors C, D anc1 E are situated at 60 ~ ~B33~
PHN.9644 ~ 5 9 oO
relative -to each other. If, as :is illustra-ted by -the vector diagram of Figure 10, two signals C ancl D with a phase difference of 60 are generated by a sui-table choice of the factor K, the third phase E is obtained by taking the difference E = D - C of the signals D and C.
If in the circuit of Figure 9 the factor K is selected so that a phase difference of 60 exists between the output signals o~ amplifiers 18 and 19, the third stator coil 8 may be energized with the third phase E by including it between the outputs of the amplifiers 18 and 19, as is represented by the dashed line in Fi~ure 9. Amplifier 20 may then be dispensed with. Stator coil 7 should then be ellergized (or wound) in a reverse sense in comparison with the situation with the signals at 120 .
l5The linear combinations C = B-XA and D = A-KB
can simply by realized by allowing cross-talk with a factor K to occur between an amplifier for -the signal A
; and an amplifier for -the signal B. This is utilized in the circuit of Figure 11. In this circuit the current ` 20 through the stator coil 6 or 7 is sensed by including a resistor 21 and 22 respectively, both for example having a resistance value Ro. The current through the stator coil 6 or 7 is controlled by an amplifier 23 and 24 respectively, which compared the signals A and B, in -this case a vol-tage, with the voltage across the resistors 21 and 22 respec-tively. The curren-ts through -the coi]s 6 and 7 are -then A/Ro and B/Ro respectively, which when the E~all elements 10 and 11 are arranged in a conven-tional manner (Figure 1) e~hibi-t a phase difference of for e~ample 120 . If a phase difference of 60 is selected, the third sta-tor coil ~
may simply be included between the outputs of the ampli-fiers 23 and 24. However, if -the Hall elements 10 and 11 are arranged at a smaller angle ~ (Figure 3), the phase difference between the currents -through the coils 6 and 7 can still be made 60 (or, if desired, 120 or other phase di~`ferences) by combining -the signals A and B, in the present case very simply by :including a cross-talk ~ 1~33~
PIIN.~644 10 5.9.80 resistor 25 with a resistance value R1 between the junction of the coil 6 ancl resistor 21 and -the junc-tion of coil 7 and resistor 22. Through resistor 21 a current A/Ro flows, through resistor 22 a current B/Ro, and through resistor 25 a current (A-B~R, so that through stator coil 6 a current I6 = P(A KB) flows and through stator coil 7 a current I7 = P(B-KA), where P = (Ro +Rl )/~oR1 and K = ~o/(Ro + R1 ) O By a suitable choice of ~, which can be determined by e~periment, for examp]e by using a variable resistor for -the resistor 25, i-t is again possible toobtain the correct phase difference.
In particular when the signals from the Hall elements are used for switching, instead of for analogue energization (as is for example shown as an alternative in Eigure 8), the waveform of the signals A and B generated by the lIall elements 10 and 11 less critical. This can be demonstra-ted by means of ~igure 12, in which Eigures 12a and 12b represent the signals A and B as triangular voltage waveforms. ~igure 12c represents the sum of said 20 signals A and B and Eigure 12d the difference of said signals A and B. It is found that also in this case the zero passages of the combinations A+B and A-B are shifted through a quartero~ the period of the signals A and B, i.e. through 90, relative to each other~ Other shifts are possible with other combinations.
Especially when the signals from the Hall elements 10 and 11 and the linear combinations thereof are employed as analogue energizing signals for the stator coils, it may occur in practice that the form and/or the streng-th of the magnetization of the permanent-magnet rotor is not suitable -to produce suitable signals in the Hall elements. A sui-table solution is -then to arrange an additional magnetic disk on the ro-tor shaft, with which disk the Hall elements co-operate. The advantage that -the two elements can be arranged near each other is then maintained, whils-t the drawback of the known mo-tor with magnetically-coded disk mentioned in -the introduction does not occur.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. An electric machine with electronic commutation, having a rotor which at least partly consists of a permanent magnetic material, which rotor co-operates with at least two stationarily arranged stator coils, which machine is equipped with at least two magneto-sensitive elements arranged on a common substrate, specifically Hall elements, for supplying signals which vary substantially sinusoidally with the rotor position in order to energize the stator coils as a function of the rotor position via an energizing circuit, the magneto-sensitive elements being arranged at a tangential angle relative to the rotor axis, which angle is smaller than the phase difference which is necessary between the energizing signals for the stator coils in order to obtain a correct energization of said stator coils, characterized in that the energizing circuit is provided with a combining circuit for linearly combining the signals supplied by at least two magneto-sensitive elements, in order to obtain at least two energizing signals having a mutual phase difference which is substantially equal to ?.
2. An electric machine as claimed in Claim 1, adapted as a two-phase or a four-phase machine, characterized in that the combining circuit supplies a signal which is proportional to the sum of the signals supplied by the two magneto-sensitive elements and a signal which is proportional to the difference of the signals supplied by the two magneto-sensitive elements.
3. An electric machine as claimed in Claim l?
characterized in that the combining circuit supplies a first signal C, which satisfies -the equation C = A+KB, and a second signal n, which satisfies the equation D = A-KB, where A is the signal supplied by PHN. 9644 12 the first one of the magneto-sensitive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and K is a predetermined constant which is such that the phase difference between the signals C and D
is equal to ? .
characterized in that the combining circuit supplies a first signal C, which satisfies -the equation C = A+KB, and a second signal n, which satisfies the equation D = A-KB, where A is the signal supplied by PHN. 9644 12 the first one of the magneto-sensitive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and K is a predetermined constant which is such that the phase difference between the signals C and D
is equal to ? .
4. An electric machine as claimed in Claim 1, characterized in that the combining circuit supplies a first signal C, which satisfies the equation C = A-KB
and a second signal D, which satisfies the equation D = B - KA, where A is the signal supplied by a first one of the magneto-sensitive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and K
is a predetermined constant which is such that the phase difference between the signals C and D is equal to ? .
and a second signal D, which satisfies the equation D = B - KA, where A is the signal supplied by a first one of the magneto-sensitive elements, B is the signal supplied by a second one of the magneto-sensitive elements, and K
is a predetermined constant which is such that the phase difference between the signals C and D is equal to ? .
5. An electric machine as claimed in Claim 4, characterized in that the energizing circuit comprises a first comparator, of which a first input is connected to a first one of the magneto-sensitive elements, of which an output is connected to the series connection of a first one of the stator coils and a first resistor, and of which a second input is connected to the junction between said first stator coil and said first resistor, a second compara-tor, of which a first input is connected to a second one of the magneto-sensitive elements, of which an output is con-nected to the series connection of a second one of the stator coils and a second resistor, and of which a second input is connected to the junction between the second stator coil and said second resistor, and a third resistor, which is included between the junction of the first stator coil and the first resistor and the junction of the second stator coil and the second resistor.
6. An electric machine as claimed in Claim 5, characterized in that the third resistor is a variable resistor.
7. An electric machine as claimed in Claim 3 or 5, characterized in that the machine is a three-phase machine having three stator coils and the combining circuit is PHN. 9644 13 adapted to supply signals with an electrical phase differ-ence of 60° to a first one and second one of said stator coils and that the third one of said stator coils is included in delta between the first and second stator coil.
8. An electric machine as claimed in Claim 1, 2 or 3, characterized in that the energizing circuit is at least partly incorporated in an integrated circuit together with the two magneto-sensitive elements.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| NL7908925 | 1979-12-12 | ||
| NL7908925A NL7908925A (en) | 1979-12-12 | 1979-12-12 | ELECTRONIC COMMUTING MOTOR. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1163314A true CA1163314A (en) | 1984-03-06 |
Family
ID=19834304
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000365916A Expired CA1163314A (en) | 1979-12-12 | 1980-12-02 | Hall element circuit for electronically commutating motor |
Country Status (6)
| Country | Link |
|---|---|
| JP (1) | JPS5694995A (en) |
| CA (1) | CA1163314A (en) |
| DE (1) | DE3045673A1 (en) |
| FR (1) | FR2471693A1 (en) |
| GB (1) | GB2070354B (en) |
| NL (1) | NL7908925A (en) |
Families Citing this family (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3144630A1 (en) * | 1980-05-10 | 1983-05-19 | Papst-Motoren GmbH & Co KG, 7742 St Georgen | Brushless DC motor arrangement, especially for disk memory drives |
| DE3215541C3 (en) * | 1982-04-26 | 1988-12-22 | Ebm Elektrobau Mulfingen Gmbh & Co, 7119 Mulfingen | COLLECTORLESS DC MOTOR |
| JPH0287959A (en) * | 1988-09-22 | 1990-03-28 | Mitsubishi Electric Corp | Brushless motor |
| GB2277214B (en) * | 1990-08-28 | 1995-02-08 | Toshiba Kk | Washing machine |
| GB2305033A (en) * | 1995-08-25 | 1997-03-26 | Norcroft Dynamics Ltd | Controlling brushless dc motors |
| JP3690338B2 (en) * | 2001-11-16 | 2005-08-31 | 松下電器産業株式会社 | Motor control device |
| GB2413905B (en) * | 2004-05-05 | 2006-05-03 | Imra Europ S A S Uk Res Ct | Permanent magnet synchronous motor and controller therefor |
| EP2117103B1 (en) | 2008-05-09 | 2010-07-14 | Micronas GmbH | Integrated switch for controlling an electromotor |
| GB2468311B (en) * | 2009-03-03 | 2014-09-17 | Dyson Technology Ltd | Positioning of a Hall-effect sensor within an electric machine |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2041548A5 (en) * | 1969-04-29 | 1971-01-29 | Thomson Csf | |
| JPS5147717Y2 (en) * | 1974-04-16 | 1976-11-17 | ||
| JPS5812838B2 (en) * | 1974-09-07 | 1983-03-10 | 日本ビクター株式会社 | Chiyokuryu brushless motor |
| US4039912A (en) * | 1974-10-30 | 1977-08-02 | Victor Company Of Japan, Limited | Three-phase brushless dc motor using two hall effect devices |
| NL7503046A (en) * | 1975-03-14 | 1976-09-16 | Philips Nv | ELECTRIC MACHINE. |
-
1979
- 1979-12-12 NL NL7908925A patent/NL7908925A/en not_active Application Discontinuation
-
1980
- 1980-12-02 CA CA000365916A patent/CA1163314A/en not_active Expired
- 1980-12-04 DE DE19803045673 patent/DE3045673A1/en not_active Withdrawn
- 1980-12-05 FR FR8025871A patent/FR2471693A1/en active Granted
- 1980-12-08 GB GB8039256A patent/GB2070354B/en not_active Expired
- 1980-12-09 JP JP17272080A patent/JPS5694995A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| FR2471693A1 (en) | 1981-06-19 |
| DE3045673A1 (en) | 1981-09-10 |
| NL7908925A (en) | 1981-07-16 |
| FR2471693B1 (en) | 1984-06-08 |
| GB2070354B (en) | 1983-08-24 |
| GB2070354A (en) | 1981-09-03 |
| JPS5694995A (en) | 1981-07-31 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |