CN200983570Y

CN200983570Y - Magnetic gearing of permanent magnet brushless electromotor

Info

Publication number: CN200983570Y
Application number: CN 200620124173
Authority: CN
Inventors: 阿哈姆德·那比尔·什拉泽
Original assignee: Electronic Products Inc
Current assignee: Electronic Products Inc
Priority date: 2006-08-10
Filing date: 2006-08-10
Publication date: 2007-11-28
Anticipated expiration: 2016-08-10

Abstract

An electromagnetic gear for a permanent magnet brushless three-phase motor comprises windings R, Y, B, wherein every winding is divided into many parts 1-5 and switchgears S1-S12 which are used for being connected with parts of every winding on a selective basis, for example switchgears can be connected with other parts of the winding R in series and/or in parallel. The electromagnetic gear provides a control device for stimulating switchgears S1-S12, and changes the features of speed/torque of motor by joining winding parts 1-5 of different structures when the motor runs.

Description

The magnetic drive of permanent magnet brushless motor

Technical field

The present invention relates to a kind of magnetic drive of permanent magnet brushless motor.

Background technology

The permanent magnet brushless motor is known, and it can provide variable-ratio output.This motor characteristic is linear, produces high moment of torsion and produce high-speed under low torque levels under low speed.

In some applications, the speed of special motors and the scope of torque characteristics can not be enough to cover desirable scope, although the power output of motor may be enough.In this environment, can utilize two kinds of selections.At first, can use more powerful motor to cover four corner, or secondly, can provide mechanical driving device for motor.These two kinds of methods all increase the cost and the weight of system.

Canadian Patent 2341095 discloses a kind of replacement method of said method, this method use wherein can be in motor change speed and moment of torsion and the needed unique addition Item technology that is switching circuit.The necessary condition of this technology is that the stator coil of motor must be split into two or more sections at least, and perhaps these sections distributed equably or irregularly by the stator slit.This switching circuit can be used to change the number of the coil segment that is connected power supply then.The control of the back electromotive force (back emf) of this arrangement utilizing induction comes control rate by changing the number of conductor that is connected to power supply selectively.Change the speed of motor, this is in fact also with changing moment of torsion.

In the main embodiment of Canadian Patent 2341095, a plurality of series connection parts that provided by the tap in the winding are provided each motor winding, and this series connection part can be connected by the cross-over connection power supply selectively.The only coiler part that utilizes the cross-over connection power supply to connect, motor will produce at a high speed, but produce low moment of torsion.But, the more a high proportion of coil that utilizes the cross-over connection power supply to be connected in series, under identical moment of torsion, this motor will produce lower speed.In this way, can change the speed of motor, rather than change moment of torsion by the winding that is connected in series selectively.

In embodiment optionally, each motor winding comprises a plurality of parts that are connected in parallel, and this part can be connected in parallel by the cross-over connection power supply selectively.The only coil segment that utilizes the cross-over connection power supply to connect, motor will produce at a high speed, but produce low moment of torsion, as described previously.But, the more a high proportion of coil that utilizes the cross-over connection power supply to be connected in parallel, under identical moment of torsion, motor will produce high torque (HT).In this way, can change the moment of torsion of motor rather than change speed by the winding that is connected in parallel selectively.

The shortcoming of any layout partly is unnecessary when service meter in some layoutprocedure, so copper (I ²R) loss is higher, reduces because the cross-sectional area of the copper that utilizes reduces with the number of live part.In addition, the existence of redundance means that the pure resistance of coil in all configurations is not optimized, so supply current or the necessary Be Controlled of voltage, to avoid damaging connecting coil.Because speed and moment of torsion are the functions of electric current, the performance of any limitations affect motor of electric current.

In most of the cases, be limited (for example, at family's power network, being restricted to 13 amperes) to the supply current of motor, therefore when some coil is outside circuit, available speed and moment of torsion will not be most preferred.

Summary of the invention

We have designed a kind of magnetic drive that alleviates the permanent magnet brushless motor of the problems referred to above now.

According to the present invention, a kind of magnetic drive of permanent magnet brushless motor is provided, comprise the winding that is divided into a plurality of parts, and switching device, be used for connecting the winding part selectively in a structure of a plurality of different structures.Wherein the every other part of each part and winding be connected in series and/be connected in parallel.

This switching device then, by series, parallel or both in conjunction with the structure that changes coil segment, can be used for changing magnetic drive, this switching device is connected to power supply.We are called magnetic drive with this layout, because it utilizes the control of the anti-electromagnetic force (back electromotive force) of induction, come control rate by changing the winding construction that is connected to power supply selectively.Along with the speed that changes motor, this changes moment of torsion.

Opposite with the known method of handling (manipulation) change speed or moment of torsion by coil, difference of the present invention is no matter all winding segments, adopt that part of structure if all helping electric motor operated.In this way, all available copper all are utilized always, keep the copper loss of motor to lose minimum thus.

Utilizing the advantage of all winding parts is the copper losss that reduce motor.Normally, count maximum, or by making diameter of wire maximum (if the number of turn is scheduled for design), the stator slit encapsulates with copper cash as much as possible by making the number of turn.In this way, for slit, the cross-sectional area of copper is maximized, so that the resistance of coil keeps minimum.Therefore, the copper loss that is used for motor will keep minimum always.

In first structure, this switching device preferably is arranged to all winding elements that are connected in parallel.In this structure, under given electric current I, motor can be issued in low relatively torque levels at a high speed.

In second structure, this switching device preferably is arranged to all winding elements that are connected in series.In this structure, under identical electric current I, motor only discharges high level moment of torsion under low relatively speed.

In the 3rd structure, this switching device preferably is arranged to some winding parts that are connected in parallel, and at least one other part is connected in series with the part that is connected in parallel.In this structure, under identical electric current, motor can reach the speed between first and second structures, and discharges the moment of torsion between first and second structures.

In order further to change the speed and the torque characteristics of motor, the voltage that is applied to winding can be the pulse duration of modulation, for example uses described switching device.

By between different structure, promptly switching speed and the torque characteristics that winding part also can change motor, to obtain intermediate characteristic between the structure that winding is switched.

Preferably, this switching device can change the structure that winding connects according to predetermined running parameter when motor moves.

Preferably, this switching device can when motor moves, output according to the device of the running parameter that is used to detect motor such as electric current, voltage, speed or moment of torsion, or, change the structure that winding connects according to the output that is used to detect by the device of the running parameter of electric motor driven article such as speed.Under the situation of the multiphase motor with a plurality of windings, when motor moved, this switching device can change the structure of the winding connection of conductive phase according to the winding of the non-conductive phase of cross-over connection or the back electromotive force of its part measurement.

In addition, this switching device can be according to the structure of time or work period or the connection of routine change winding.

In addition, can be provided for the device that the artificially changes the winding syndeton.

Preferably in assembling process, all parts of winding are twined by parallel connection, and electric current preferably flows through each part in identical direction.

A part of winding can comprise the number of turn different with other parts.Simultaneously, a part of winding can comprise a conductor, has the cross-sectional area of the conductor that is different from other parts.

The accompanying drawing note

Now only by example and this inventive embodiment is described with reference to the drawings, wherein:

Fig. 1 is the single-phase schematic diagram according to 3 phase permanent magnet brushless motors of the present invention;

Fig. 2 to 6 shows the various connection diagrams of part of the motor of Fig. 1;

Fig. 7 shows the connection according to Fig. 2 to 6, the tabulation of the on off state of the motor of Fig. 1;

Fig. 8 is used for the speed of connection of Fig. 2 to 6 and the curve of moment of torsion; And

Fig. 9 illustrates that the motor that how to use Fig. 1 realizes being used for the speed of desired electrical characteristics of motivation of washing machine and the curve of moment of torsion.

Embodiment

Fig. 1 with reference to drawing shows 3 phase permanent magnet brushless DC motors, comprises the phase R of three Y-connections, Y, B 18 slits, 12 magnetic poles and 1 slot pitch.Stator outer diameter, internal diameter and length are respectively 110mm, 55mm and 75mm.Air gap is 0.5mm, and magnet width and thickness are respectively 10mm and 4mm.Each comprises winding mutually, for example has the copper part 1-5 of five conductors or so-called 0.63mm glazing, the winding in parallel altogether of these associated stator slits by motor.The voltage that offers motor is 180 volts of DC.

The first end of the first 1 of one phase R is connected to other two-phases Y, the first end of the first of B.The first end of the first of this phase R also is connected to the first end of the second portion 2 of phase R by switch S 1.Equally, the first end of other parts 3,4,5 is connected to adjacent part by each switch S 2, S3, S4.

Similarly, the second end of the first 1 of phase R is connected to the second end of the second portion 2 of phase R by switch S 9.Equally, the second end of other parts 3,4,5 is connected to adjacent part by each switch S 10, S11, S12.The second end of the 5th part 5 also is connected to power supply.

The first end of the first 1 of phase R is connected to the first end of the second portion 2 of phase R by switch S 5.Equally, the second end of other parts 2,3,4 is connected to the first end of adjacent part by each switch S 6, S7, S8.

With reference to the Fig. 2 that draws, 7 and 8, when motor was activated at first, only switch S 5 to S8 was excited, so that part 1-5 is connected in series.In this way, supply current flows through each series connection part 1-5 in respect to the equidirectional of the polarity orientation (shown in the arrow among Fig. 1) of each part: importantly this is this situation always.Allow a part (for example, part 4) be directed in the opposite direction, the magnetic flux that produces by part 4 will with

part

1,2,3 is relative with 5 magnetic flux that produce.

The moment of torsion of motor is directly proportional with electric current, and as long as the beginning moment of torsion is enough high, to overcome the load that attaches to motor, rotor begins to rotate.These are followed and produce back electromotive force in coils, and this back electromotive force begins to offset supply power voltage, so that the available electric current of phase coil begins to reduce, because the moment of torsion that is produced by motor.

The number of turn in this back electromotive force and the phase coil, the magnetic flux, the permanent magnet poles that are produced by permanent magnet are directly proportional to the angular speed of number and rotor.Other factors, as coil and the number of interconnection mutually and phase also influence the back electromotive force of generation.

The result of these behaviors is that motor will continue to quicken, and equals load up to the moment of torsion that is produced by it.From this sensing, motor will continue rotation with constant speed.If in any case, this load is changed, and motor will automatically be adjusted its moment of torsion (therefore, adjusting its speed) so, so that make load balance.

Maximal rate by motor can be realized does not take place when having load to attach to motor.Ideally, these generations when the back electromotive force that produces in phase coil equals supply power voltage in the case, do not have electric current to flow through coil, to produce any moment of torsion; This situation is called as no-load speed.

In fact, back electromotive force will keep being lower than more or less supply power voltage (even under no-load speed) always.This is because the sub-fraction of power supply is used to fully overcome because windage and the frictional force of bearing and the iron loss of motor.

Find out obviously that from the curve of Fig. 8 motor is limited to the speed of Fig. 2 and the performance standard in the torque wire.This curve representation motor can be managed the maximum speed of 584rpm and the peak torque of 28.1Nm.As further example, the maximal rate of the moment of torsion of 8Nm up to about 400rpm also can be provided, otherwise or, motor moves with 400rpm, and the peak torque up to about 8Nm can be provided.

If the motor performance of wishing belongs to beyond the 10amp line, 14Nm during 600rpm for example, motor parameter need be changed so, so that satisfy the secondary power demand.

With reference to the Fig. 3 that draws, 7 and 8, by changing the wherein connected structure of all motor windings, can change the performance of motor.By according to Fig. 7 exciting switch,

part

1 and 2 can be connected in parallel, and then should and joint group and part 3,4 and 5 be connected in series (being connected in series mutually).

Find out obviously that from the curve of Fig. 8 motor is limited to the performance standard in the speed v moment of torsion circuit of Fig. 3 now.This curve motor will produce the no-load speed of 725rpm and the stall torque of 34.6Nm now.

With reference to the Fig. 4 that draws, 7 and 8, by exciting this switch, can change the performance of motor according to Fig. 7 so that

part

1,2 and 3 is connected in parallel, and then should and joint group and part 4 and 5 be connected in series (being connected in series mutually).

Find out obviously that from the curve of Fig. 8 motor is limited to the speed of Fig. 4 and the performance standard in the torque wire now.This curve shows that this motor will produce the no-load speed of 966rpm and the stall torque of 46.1Nm now.

With reference to the Fig. 5 that draws, 7 and 8, by exciting this switch, can change the performance of motor according to Fig. 7 once more, so that

part

1,2,3 and 4 is connected in parallel, also joint group and part 5 are connected in series then.

Find out obviously that from the curve of Fig. 8 this motor is limited to the speed of Fig. 5 and the performance standard in the torque wire now.This curve shows that motor will produce the no-load speed of 1449rpm and the stall torque of 69.0Nm now.

With reference to the Fig. 6 that draws, 7 and 8, can finally change the performance of motor according to Fig. 7 by exciting this switch, so that

part

1,2,3 and 4 is connected in parallel, and also joint group and part 6 are connected in series then.

Find out obviously that from the curve of Fig. 8 this motor is limited to the speed of Fig. 6 and the performance standard in the torque wire now.This curve shows that motor will produce the no-load speed of 2898rpm and the stall torque of 136.7Nm now.

At first glance, people may think that best choice will be the structure (that is, all part parallel connections) of execution graph 6, because this is chosen in speed and the moment of torsion aspect all obtains maximum scope.But, are identical (180 volts of DC) although offer the voltage of all structures.But the electric current of structure is different mutually.In actual applications, will be the electric current restriction always, for example most of household electrical appliance are limited to 13 amperes.With reference to figure 8,, will see that so the peak torque that can realize to the structure of Fig. 6 by Fig. 2 is respectively 29.7,23.7,17.8,11.9 and 5.9Nm if be not applied to each structure according to (notional) 10 amperes of restrictions of reality.Therefore, between each structure, change, keep motor simultaneously within 10 amperes of restrictions, can obtain the performance shown in the shaded area of this curve by console switch.Thus, be to be understood that the drive system that can be provided for motor by console switch, allow motor to produce Billy with any single structure (current source) possible higher moment of torsion (under low speed) and more speed (having low moment of torsion) thus with restriction.Therefore, when motor was excited at first, all parts can be connected in series, and as shown in Figure 2, so that within 10 amperes of restrictions, well obtained high starting torque.

Switch S 1 to S12 can be relay or semiconductor device.Under the situation of semiconductor device, in single encapsulation, can comprise a plurality of devices.Each switch, S1 for example, S5 and S9 can be configured to single machinery or electronic switch.In the case, when 1 and 9 conductings, 5 end so.When 5 conductings, 1 and 9 end so.The every phase place of this method only needs 4 switches, replaces 12 switches.

With reference to the Fig. 9 that draws, show the curve of needed speed of washing machine overlapping on the curve of Fig. 8 and torque curve 20.At present, the induction motor that runs at high speed by use usually has suitable mechanical driving device and driving-belt or speed and moment of torsion by using big DC direct drive motor acquisition to need.But, can see, in using the electric current restriction that directly drives brushless DC motor according to reasonable size of the present invention, can easily obtain the velocity interval and the moment of torsion that need.

To see that for needed speed of washing machine and torque curve are provided Fig. 3 and 4 structure are optional, therefore can obtain some cost savings by omitting some switches.

It should be noted that single-phase interior multistage coil needn't use the identical diameter of wire or the identical number of turn to twine, but all must twine in an identical manner mutually.For example, the part 1 of each phase must and have the identical number of turn with identical lead winding.Coiler part 2 can have the different numbers of turn and it and can use the diameter of wire that is different from part 1 to twine, but the coil segment of each phase 2 must be identical and be applied to every other section same identical.

Be to be understood that working as above-described embodiment utilizes the 3-phase time, the present invention is applied to have the motor of many phases.In addition, the present invention also is applied to have the permanent magnet brushless synchronous motor of similar speed-torque performance.

The structure that Fig. 2 to Fig. 6 discusses is not unique possible combination.For example, another possible combination is that

coiler part

1 and 2 is connected in parallel and coiler part 3 and 4 is connected in parallel, and two parallel groups are connected in series mutually and are connected in series with remainder 5.This structure will produce the motor performance identical with layout shown in Figure 4.

Can obtain another structure by the

part

1,2 and 3 that is connected in parallel with the part 4 and 5 that is connected in parallel, this also joint group then is connected in series mutually.This will obtain and the identical motor performance of performance that is produced by structure shown in Figure 5.

The number (each phase) of the winding part that is provided is provided the number of the speed-torsional performance that can obtain, and this number is limited to some Finite Number.When motor during as far as possible near its no-load speed, electric motor operated is in the most effective rank.For this reason, by automatically reducing its speed (on speed-torsional performance line), it is undesirable allowing the increase of motor compensating load.By magnetic drive, with better satisfying the needs that load increases, so that obtain new torque levels, motor continues operation near its no-load speed simultaneously.But in order to satisfy all possible torque levels (in the given range of motor), motor will need the number of blades of unlimited magnetic drive, therefore need the unlimited winding part and the number of blades of switch.

In embodiment optionally, can obtain the arbitrary speed torque curve that obtains by the structure that changes winding by between two structures, very rapidly exchanging, so that motor is not operated under the performance of any one structure, but in the somewhere of centre.Quick switching between two structures can obtain to switch (S1 to S12) by pulse duration (PWM) signal of presenting modulation, and the duty ratio of PWM is changed, with middling speed and the moment of torsion that obtains to wish.

For example, consider to have all first structures that are connected in parallel; This transmission device provides maximum speed, and motor can obtain, so it is the highest transmission device.Next thus transmission device, by connecting a winding element of connecting with residue part in parallel, this provides next maximum speed.

If PWM has 100% duty ratio, this transmission device also keeps from the highest lower transmission device of the next one of changing into so.Otherwise if select 0% duty ratio (that is, no signal), motor will keep the highest transmission device so.Select the duty ratio between 0 and 100% will obtain transmission device, and therefore obtain electromotor velocity and moment of torsion between two the highest transmission devices, that is, and intermediate gearing.

If wish, this transmission device can directly switching between the highest transmission device (all part parallel connections) and minimum transmission device (all parts series connection).The duty ratio of PWM can be used to select the speed/torque performance so, between two extreme values of motor performance in Anywhere.But, resolution and therefore utilize accuracy that its accuracy need can to obtain speed to increase to reduce with the gamut of transmission device ratio.These can compensate by increasing the PWM frequency to a certain extent.

Claims

1. a magnetic drive comprises winding and the switching device that is divided into a plurality of parts, this switching device is used for connecting coil assembly selectively in a structure of a plurality of different structures, it is characterized in that this magnetic drive is the magnetic drive of permanent magnet brushless motor, each coil assembly by described switching device and this winding every other unit Series and/or be connected in parallel.

2. magnetic drive according to claim 1 is characterized in that this switching device is arranged to all coil assemblies that are connected in parallel.

3. magnetic drive according to claim 1 is characterized in that this switching device is arranged to all coil assemblies that are connected in series.

4. magnetic drive according to claim 1 is characterized in that this switching device is arranged to some coil assemblies that are connected in parallel, and miscellaneous part is connected with the unit Series that this is connected in parallel at least.

5. magnetic drive according to claim 1, the voltage that it is characterized in that being applied to this winding is to use the pulse duration of described switching device modulation.

6. magnetic drive according to claim 5, the voltage that it is characterized in that being applied to this winding are by exciting the pulse duration of described switching device modulation selectively.

7. magnetic drive according to claim 1, it is characterized in that this magnetic drive comprises is used for repeatedly encouraging described switching device, with the described coil assembly of change between different syndetons, thus the device of motor characteristic in the middle of between the different syndetons that this winding is repeatedly switched, obtaining.

8. magnetic drive according to claim 1, it is characterized in that this magnetic drive comprises the equipment of the running parameter that is used for this magnetic drive of sensing and control device, this control device is arranged to, when motor moves, according to the output of described equipment, in a structure of a plurality of different structures, connect the parts of this winding selectively.

9. magnetic drive according to claim 8, it is characterized in that this equipment is arranged to the back electromotive force at the winding two ends of measuring non-conductive parts or the phase place of this winding, this control device is arranged to when motor moves, according to the output of described equipment, in a structure of a plurality of different structures, connect the parts of this winding selectively.

10. magnetic drive according to claim 1, it is characterized in that this magnetic drive comprises the equipment of the running parameter that is used for the article that sensing driven by motor and control device, this control device is arranged to, when motor moves, according to the output of described equipment, in a structure of a plurality of different structures, connect the parts of this winding selectively.

11. magnetic drive according to claim 1, it is characterized in that this magnetic drive comprises is used to be connected to the output of timer and the input of control device, this control device is arranged to, when motor moves, according to the output of described timer, in a structure of a plurality of different structures, connect the parts of this winding selectively.

12. magnetic drive according to claim 1, it is characterized in that this magnetic drive comprises the input of the output that is used to the equipment that is connected to, this equipment is arranged to the work of the article of control motor and control device driving, this control device is arranged to, when motor moves, according to the output of described timer, in a structure of a plurality of different structures, connect the parts of this winding selectively.

13. magnetic drive according to claim 1 is characterized in that this switching device is arranged to manually start.

The winding 14. magnetic drive according to claim 1, all parts that it is characterized in that each winding are parallel to each other.

15. magnetic drive according to claim 1 is characterized in that these parts are connected, so that electric current flows through each parts on identical direction.

16. magnetic drive according to claim 1 is characterized in that parts of this winding comprise the number of turn different with other parts.

17. magnetic drive according to claim 1 is characterized in that parts of this winding comprise a conductor, this conductor has the cross-sectional area of the conductor that is different from other parts.