CN113517801A - Stepless speed change magnetic gear - Google Patents
Stepless speed change magnetic gear Download PDFInfo
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- CN113517801A CN113517801A CN202110275081.6A CN202110275081A CN113517801A CN 113517801 A CN113517801 A CN 113517801A CN 202110275081 A CN202110275081 A CN 202110275081A CN 113517801 A CN113517801 A CN 113517801A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
- H02K49/10—Dynamo-electric clutches; Dynamo-electric brakes of the permanent-magnet type
- H02K49/102—Magnetic gearings, i.e. assembly of gears, linear or rotary, by which motion is magnetically transferred without physical contact
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K49/00—Dynamo-electric clutches; Dynamo-electric brakes
- H02K49/10—Dynamo-electric clutches; Dynamo-electric brakes of the permanent-magnet type
- H02K49/104—Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element
- H02K49/106—Magnetic couplings consisting of only two coaxial rotary elements, i.e. the driving element and the driven element with a radial air gap
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02K—DYNAMO-ELECTRIC MACHINES
- H02K2213/00—Specific aspects, not otherwise provided for and not covered by codes H02K2201/00 - H02K2211/00
- H02K2213/03—Machines characterised by numerical values, ranges, mathematical expressions or similar information
Abstract
The invention discloses a stepless speed change magnetic gear, which sequentially comprises from an inner layer to an outer layer: the magnetic pole of the inner rotor, the magnetic adjusting magnetic ring, the stator core and the stator winding; when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the inner rotor magnetic pole, and the load is connected with the magnetic regulating magnetic ring; when the load is a high-rotating-speed and low-torque load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor; and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
Description
Technical Field
The present invention relates to the field of stepless speed change technology, and more particularly, to a stepless speed change magnetic gear and a method for driving a load using the stepless speed change magnetic gear.
Background
The earliest magnetic gear was produced in the beginning of the last century, but the transmission efficiency is low, so that the magnetic gear is not regarded as important, and the research and application of the magnetic gear are slow in the last hundred years. In 2001, k.atallah and d.howe of the university of sheffield, england, first proposed a concentric magnetic gear based on the principle of magnetic field modulation, thereby bringing the research and application of magnetic gears into a new phase. The novel magnetic gear has the remarkable advantages of large torque density, no lubrication, high reliability, long service life, low noise and the like, and has wide application prospect in the aspects of electric transmission and novel motor design. However, because the magnetic gear transmission ratio is fixed, the application of the magnetic gear transmission ratio is limited in occasions where variable speed adjustment is needed.
Currently, with the increasing social requirements for environmental protection and energy conservation, variable speed operation of motors in industrial and civil fields is very common. At present, the speed regulation of an alternating current motor is usually realized by adopting a frequency converter, but the frequency converter, particularly a high-voltage frequency converter, has higher price and higher speed regulation cost, and harmonic harm caused by the frequency converter is not visible. In recent years, a brushless doubly-fed motor for realizing speed regulation of an alternating-current motor by using a smaller capacity of a frequency converter attracts continuous attention of researchers, but the structural design of the brushless doubly-fed motor is still to be further improved, for example, the brushless doubly-fed motor has the defects of larger loss, low conversion rate of magnetic field series and the like.
Therefore, a technique is required to realize stepless speed change of the magnetic gear.
Disclosure of Invention
The technical scheme of the invention provides a stepless speed change magnetic gear and a method for driving a load by utilizing the stepless speed change magnetic gear so as to solve the problem of stepless speed change control of a motor.
In order to solve the above problems, the present invention provides a stepless speed change magnetic gear, which comprises, from an inner layer to an outer layer: the magnetic pole of the inner rotor, the magnetic adjusting magnetic ring, the stator core and the stator winding;
when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the inner rotor magnetic pole, and the load is connected with the magnetic regulating magnetic ring;
when the load is a high-rotating-speed and low-torque load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor;
and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
Preferably, the method comprises the following steps:
when the number of pole pairs of the inner rotor magnetic pole is p1The number of the iron blocks on the magnetic adjusting magnetic ring is N, and the pole pair number p is obtained after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core comprises space harmonic waves and the pole pair number p of the space harmonic wavesmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± ∞, the mechanical rotation angular velocity of the magnetic field including each harmonic in the space harmonics in the air gap magnetic field on the stator iron core side is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted; for constant torque production, the number of pole pairs p of the stator winding2＝N-p1；
The mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating magnetic ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
Preferably, when a load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
preferably, when a load is connected with the inner rotor magnetic pole, the rotating speed of the load is reduced when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotating speed is increased;
when a load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
Preferably, the method further comprises the following steps:
the power transmitted to the inner rotor magnetic pole of the magnetic gear by the frequency converter and the magnetic regulating magnetic ring is equal to the sum of the power of the rotating magnetic field of the magnetic regulating magnetic ring and the frequency converter; meanwhile, the output torque of the inner rotor magnetic pole of the magnetic gear is equal to the sum of the electromagnetic torques output by the frequency converter and the magnetic regulating ring, and a power balance formula is obtained:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by said inner-ring sub-poles of the magnetic gearsRepresenting the mechanical power, P, output by the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersRepresents the torque transferred to the inner rotor magnetic pole by the magnetic regulating magnetic ring,Tcrepresenting the torque transmitted by the inverter to the poles of the inner rotor.
Preferably, the method further comprises the following steps:
substituting the mechanical angular velocity of the load end when the load is connected with the inner rotor into the power balance formula,
assuming the mechanical power P output by the frequency convertercMechanical power P output by magnetic regulating rings(i.e., the mechanical power output by the drive motor) is KpAnd then:
from the above formula, when ΩcAnd omegasK 'with same steering'pIs negative when ΩcAnd omegasK 'when the steering directions are opposite'pIs positive, mixing K'pp1Ωr＝(N-p1)ΩcSubstituting a calculation formula of the mechanical angular velocity of the load end when the load is connected with the inner rotor to obtain the mechanical angular velocity of the load end:
from the above formula, when the frequency converter does not output mechanical power, i.e. when the stator winding is supplied with direct current, Ωc0, inner rotor magnetic pole rotation speed omegar0＝NΩs/p1；
For the case of a load connected to the inner rotor, the mechanical power P output by the frequency converter iscMechanical power P output by magnetic regulating rings(i.e., mechanical power output by the drive motor) ratio KpAnd the mechanical angular velocity Ω of the loadrThe calculation formula shows that when the stator winding alternating current generates the rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering (i.e. the driving motor is steered) is the same, KpNegative, the load rotation speed of the inner rotor magnetic pole is lower than omegar0At the moment, the frequency converter feeds electric energy into the power supply; when the stator winding generates a rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering is reversed, KpPositive, the loaded speed of the inner rotor poles is higher than omegar0The frequency converter absorbs electric energy from the power supply;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, electric energy is fed into a power supply through a frequency converter, so that the rotating speed of the load is reduced;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased.
If the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorr(i.e., mechanical power output from the drive motor) ratio K'pExpressed as:
from the above formula, when ΩcAnd omegarK 'with same steering'pIs positive when ΩcAnd omegarK 'when the steering directions are opposite'pIs negative, mixing K'pp1Ωr＝(N-p1)ΩcSubstituting the calculation formula of the mechanical angular speed of the load when the load is connected with the magnetic regulating ring, wherein the load rotating speed is as follows:
for the condition that the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercWith output from inner-ring rotorMechanical power Pr(i.e., mechanical power output from the drive motor) ratio K'pAnd the mechanical angular velocity Ω of the loadsCan know the rotating magnetic field omega generated by the current of the stator windingcMagnetic field omega with the inner rotor magnetic polerK 'when the steering directions (i.e. the driving motors are steered) are the same'pIf the voltage is positive, the frequency converter absorbs electric energy from the power supply, and the rotating speed of the load is increased; when the stator winding generates a rotating magnetic field omegacMagnetic field omega with the inner rotor magnetic polerWhen the steering is reversed, K'pAnd when the load is negative, the frequency converter feeds electric energy into the power supply, and the rotating speed of the load is reduced.
When a load is connected with the magnetic regulating magnetic ring, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased; when the load is connected with the magnetic adjusting magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
In accordance with another aspect of the present invention, there is provided a method of driving a load using a continuously variable magnetic gear, the method comprising:
the method comprises the following steps of establishing a structure from an inner layer to an outer layer: the magnetic gear comprises an inner rotor magnetic pole, a magnetic adjusting magnetic ring, a stator core and a stator winding;
when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the inner rotor magnetic pole, and the load is connected with the magnetic regulating magnetic ring;
when the load is a high-rotating-speed and low-torque load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor;
and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
Preferably, the method comprises the following steps:
when the number of pole pairs of the inner rotor magnetic pole is p1The number of the iron blocks on the magnetic adjusting magnetic ring is N, and the pole pair number p is obtained after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core comprises space harmonic waves and the pole pair number p of the space harmonic wavesmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± ∞, the mechanical rotation angular velocity of the magnetic field including each harmonic in the space harmonics in the air gap magnetic field on the stator iron core side is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted; for constant torque production, the number of pole pairs p of the stator winding2＝N-p1；
The mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating magnetic ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
Preferably, when a load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
preferably, when a load is connected with the inner rotor magnetic pole, the rotating speed of the load is reduced when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotating speed is increased;
when a load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
Preferably, the method further comprises the following steps:
the power transmitted to the inner rotor magnetic pole of the magnetic gear by the frequency converter and the magnetic regulating magnetic ring is equal to the sum of the power of the rotating magnetic field of the magnetic regulating magnetic ring and the frequency converter; meanwhile, the output torque of the inner rotor magnetic pole of the magnetic gear is equal to the sum of the electromagnetic torques output by the frequency converter and the magnetic regulating ring, and a power balance formula is obtained:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by said inner-ring sub-poles of the magnetic gearsRepresenting the mechanical power, P, output by the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersRepresenting the torque, T, transmitted by the magnetic modulating ring to the poles of the inner rotorcRepresenting the torque transmitted by the inverter to the poles of the inner rotor.
Preferably, the method further comprises the following steps:
substituting the mechanical angular velocity of the load end when the load is connected with the inner rotor into the power balance formula,
assuming the mechanical power P output by the frequency convertercMechanical power P output by magnetic regulating ringsThe ratio of KpAnd then:
from the above formula, when ΩcAnd omegasSame steering KpIs negative when ΩcAnd omegasWhen the steering is reversed KpTo be positive, K ispNΩs＝-(N-p1)ΩcSubstituting a calculation formula of the mechanical angular velocity of the load end when the load is connected with the inner rotor to obtain the mechanical angular velocity of the load end:
from the above formula, when the frequency converter does not output mechanical power, i.e. when the stator winding is supplied with direct current, Ωc0, inner rotor magnetic pole rotation speed omegar0＝NΩs/p1；
For the case of a load connected to the inner rotor, the mechanical power P output by the frequency converter iscMechanical power P output by magnetic regulating rings(i.e., mechanical power output by the drive motor) ratio KpAnd the mechanical angular velocity Ω of the loadrThe calculation formula shows that when the stator winding alternating current generates the rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering (i.e. the driving motor is steered) is the same, KpNegative, the load rotation speed of the inner rotor magnetic pole is lower than omegar0At the moment, the frequency converter feeds electric energy into the power supply; when the stator winding generates a rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering is reversed, KpPositive, the loaded speed of the inner rotor poles is higher than omegar0The frequency converter being absorbed from the power supplyElectrical energy;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, electric energy is fed into a power supply through a frequency converter, so that the rotating speed of the load is reduced;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased.
If the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorrIs to K'pExpressed as:
from the above formula, when ΩcAnd omegarK 'with same steering'pIs positive when ΩcAnd omegarK 'when the steering directions are opposite'pIs negative, mixing K'pp1Ωr＝(N-p1)ΩcSubstituting the calculation formula of the mechanical angular speed of the load when the load is connected with the magnetic regulating ring, wherein the load rotating speed is as follows:
for the condition that the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorr(i.e., mechanical power output from the drive motor) ratio K'pAnd the mechanical angular velocity Ω of the loadsCan know the rotating magnetic field omega generated by the current of the stator windingcMagnetic field omega with the inner rotor magnetic polerK 'when the steering directions (i.e. the driving motors are steered) are the same'pIf the voltage is positive, the frequency converter absorbs electric energy from the power supply, and the rotating speed of the load is increased; when the stator winding is generatedOf the rotating magnetic field omegacMagnetic field omega with the inner rotor magnetic polerWhen the steering is reversed, K'pAnd when the load is negative, the frequency converter feeds electric energy into the power supply, and the rotating speed of the load is reduced.
When a load is connected with the magnetic regulating magnetic ring, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased; when the load is connected with the magnetic adjusting magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
The invention provides a magnetic gear design scheme capable of realizing stepless speed change by utilizing a magnetic field modulation principle of a novel magnetic gear and a variable frequency speed change control strategy of a motor. The invention provides a stepless speed change magnetic gear, which sequentially comprises the following components from an inner layer to an outer layer: the magnetic pole of the inner rotor, the magnetic adjusting magnetic ring, the stator core and the stator winding; when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the magnetic poles of the inner rotor, and the load is connected with the magnetic regulating ring; when the load is a high-rotating-speed and low-torque type load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor; and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
Drawings
A more complete understanding of exemplary embodiments of the present invention may be had by reference to the following drawings in which:
FIG. 1 is a schematic view of a continuously variable magnetic gear according to a preferred embodiment of the present invention;
FIG. 2 is a schematic view of the internal structure of a continuously variable magnetic gear according to a preferred embodiment of the present invention; and
fig. 3 is a flow chart of a method for driving a load using a continuously variable magnetic gear according to a preferred embodiment of the present invention.
Detailed Description
The exemplary embodiments of the present invention will now be described with reference to the accompanying drawings, however, the present invention may be embodied in many different forms and is not limited to the embodiments described herein, which are provided for complete and complete disclosure of the present invention and to fully convey the scope of the present invention to those skilled in the art. The terminology used in the exemplary embodiments illustrated in the accompanying drawings is not intended to be limiting of the invention. In the drawings, the same units/elements are denoted by the same reference numerals.
Unless otherwise defined, terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Further, it will be understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense.
Fig. 1 is a schematic view of a continuously variable magnetic gear according to a preferred embodiment of the present invention. As shown in fig. 1, the present invention provides a magnetic gear capable of realizing a stepless speed change operation of a motor,
as shown in fig. 1, the present invention provides a stepless speed change magnetic gear, which comprises, from an inner layer to an outer layer: the magnetic circuit comprises an inner rotor magnetic pole 2, a magnetic regulating magnetic ring 1, a stator iron core 4 and a stator winding 5; when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the magnetic poles of the inner rotor, and the load is connected with the magnetic regulating ring; when the load is a high-rotating-speed and low-torque type load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor; and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
In the embodiment of the invention, one permanent magnetic pole magnetic gear in the novel magnetic gear is replaced by electric excitation, and the magnetic pole is kept static and unchanged; and the other permanent magnetic pole magnetic gear and the magnetic regulating ring are rotating parts and are respectively connected with the driving motor and the load. When the electric excitation is electrified with direct current, the rotating parts of the driving end and the load end keep a fixed rotating speed ratio, and when the electric excitation is electrified with positive sequence alternating current and negative sequence alternating current with different frequencies, the rotating speed of the load end can be continuously changed along with the frequency of the alternating current. As shown in fig. 1, a driving motor is rigidly connected with a magnetic modulating magnetic ring, loads such as a water pump and a fan are rigidly connected with an inner rotor, and a stator core and a winding are arranged on the outermost layer; wherein, 1 is a magnetic adjusting ring, 2 is an inner rotor magnetic pole, 3 is a load side bearing, 4 is a stator shell, 5 is a stator winding, 6 is a drive end bearing, and 7 is a frequency converter. When the load is a low-rotating-speed large-torque load, the driving motor is connected with the inner rotor, and the load is connected with the magnetic regulating magnetic ring; and on the contrary, when the load is a high-rotating-speed and small-torque load, the driving motor is connected with the magnetic regulating magnetic ring, and the load is connected with the inner rotor.
Preferably, when the number of pole pairs of the inner rotor magnetic pole is p1The number of iron blocks on the magnetic regulating magnetic ring is N, and the pole pair number p is after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core contains space harmonic, and the pole pair number p of the space harmonicmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± ∞, and the mechanical rotation angular velocity of the magnetic field including each of the space harmonics in the air gap magnetic field on the stator core side is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted; number of pole pairs p of stator winding for constant torque generation2＝N-p1；
The mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
Suppose the number of pole pairs of the inner rotor is p1The number of the magnetic adjusting magnets on the magnetic adjusting magnetic ring is N, and the pole pair number p is obtained after the outer layer stator winding is electrified2＝N-p1。
According to the working principle of a magnetic gear, after passing through a magnetic adjusting magnetic ring, an air gap magnetic field close to a stator side contains a large number of space harmonics, and the pole pair number p of the harmonicsmk| mp + kN |, where m ═ 1, 3, 5., ∞; k ═ 0, ± 1, ± 2, ± 3, ·, ± ∞. Mechanical rotation angular velocity of each harmonic magnetic field close to air gap on stator side
The working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, the number of pole pairs of the magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the rotor within the magnetic gearsAnd the mechanical rotating speed of the magnetic regulating magnetic ring is represented. Thus, to produce a constant torque, the stator winding pole pair number p2＝N-p1. The mechanical angular velocity of the stator magnetic field is assumed to be omegacThen, from (1), we can obtain:
when the stator winding is energized with DC current, its magnetic field is stationary, omegacWhen the magnetic field adjusting magnetic ring and the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1. When the stator winding is introduced with positive sequence alternating current with the frequency fc, the mechanical angular velocity omega of the stator rotating magnetic fieldc＝2πfc/(N-p1)。
Preferably, when the load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
preferably, when the load is connected with the magnetic poles of the inner rotor, the rotating speed of the load is reduced when the stator core is introduced with positive sequence alternating current; when the phase sequence of the alternating current of the stator winding is changed, the rotating speed of the load is increased;
when the load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
In the invention, if the load is connected with the inner rotor, the mechanical angular speed of the load end is as follows:
if the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load end is as follows:
and (3) when the load is connected with the inner rotor, the rotating speed of the load is reduced when the stator is electrified with positive sequence alternating current. When changing the phase sequence of the stator winding alternating current, the method is equivalent to changing f to fcAnd (3) substituting, the load rotating speed is increased. Under the condition that the load is connected with the magnetic regulating magnetic ring, the influence of the electrifying phase sequence of the stator on the rotating speed of the load is just opposite.
Preferably, the method further comprises the following steps:
the power transmitted to the inner rotor magnetic pole of the magnetic gear by the frequency converter and the magnetic regulating magnetic ring is equal to the sum of the power of the rotating magnetic field of the magnetic regulating magnetic ring and the frequency converter; meanwhile, the output torque of the inner rotor magnetic pole of the magnetic gear is equal to the sum of the electromagnetic torques output by the frequency converter and the magnetic regulating ring, and a power balance formula is obtained:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by the inner ring sub-poles of the magnetic gearsMechanical power, P, representing the output of the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersIndicating the torque, T, transmitted by the magnetic field-regulating ring to the poles of the inner rotorcRepresenting the torque transmitted by the inverter to the poles of the inner rotor.
Preferably, the method further comprises the following steps:
substituting the mechanical angular velocity of the load end into a power balance formula when the load is connected with the inner rotor,
assuming the mechanical power P output by the frequency convertercMechanical power P output by magnetic regulating ringsThe ratio of KpAnd then:
from the above formula, when ΩcAnd omegasSame steering KpIs negative when ΩcAnd omegasWhen the steering is reversed KpTo be positive, K ispNΩs＝-(N-p1)ΩcSubstituting a calculation formula of the mechanical angular velocity of the load end when the load is connected with the inner rotor to obtain the mechanical angular velocity of the load end:
from the above formula, when the frequency converter does not output mechanical power, i.e. when the stator winding is supplied with direct current, Ωc0, inner rotor magnetic pole rotation speed omegar0＝NΩs/p1；
For the case of a load connected to the inner rotor, the mechanical power P output by the frequency converter iscMechanical power P output by magnetic regulating rings(i.e., mechanical power output by the drive motor) ratio KpAnd the mechanical angular velocity Ω of the loadrThe calculation formula shows that when the stator winding alternating current generates the rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering (i.e. the driving motor is steered) is the same, KpNegative, the load rotation speed of the inner rotor magnetic pole is lower than omegar0At the moment, the frequency converter feeds electric energy into the power supply; when the stator winding generates a rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering is reversed, KpPositive, the loaded speed of the inner rotor poles is higher than omegar0The frequency converter absorbs electric energy from the power supply;
when the load is connected with the magnetic poles of the inner rotor, when the rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced;
when the load is connected with the magnetic poles of the inner rotor, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from the power supply, so that the rotating speed of the load is increased.
If the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorrIs to K'pExpressed as:
from the above formula, when ΩcAnd omegarK 'with same steering'pIs positive when ΩcAnd omegarK 'when the steering directions are opposite'pIs negative, mixing K'pp1Ωr＝(N-p1)ΩcWhen substituting the load and adjusting the magnetism magnetic ring and being connected, the computational formula of the mechanical angular velocity of load, the load rotational speed is:
for the condition that the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorr(i.e., mechanical power output from the drive motor) ratio K'pAnd the mechanical angular velocity Ω of the loadsThe calculation formula shows that when the current of the stator winding generates the rotating magnetic field omegacMagnetic field omega with inner rotor magnetic polerK 'when the steering directions (i.e. the driving motors are steered) are the same'pIf the voltage is positive, the frequency converter absorbs electric energy from the power supply, and the rotating speed of the load is increased; when the stator winding generates a rotating magnetic field omegacMagnetic field omega with inner rotor magnetic polerWhen the steering is reversed, K'pAnd when the load is negative, the frequency converter feeds electric energy into the power supply, and the rotating speed of the load is reduced.
When the load is connected with the magnetic regulating magnetic ring, when the rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from the power supply, so that the rotating speed of the load is increased; when the load is connected with the magnetic regulating magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
The invention takes the connection of the load and the magnetic gear inner rotor as an example, if the loss of the magnetic gear is ignored, the power transmitted to the magnetic gear inner rotor by the frequency converter and the magnetic regulating magnetic ring is equal to the sum of the power of the magnetic regulating magnetic ring and the rotating magnetic field of the frequency converter; meanwhile, the output torque of the rotor in the magnetic gear is equal to the sum of the electromagnetic torques output by the frequency converter and the magnetic regulating magnetic ring, so that the following results are obtained:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr (5)
p in formula (5)rRepresenting the mechanical power, P, transmitted by the inner ring of the magnetic gear to the loadsMechanical power, P, representing the output of the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersIndicating the torque, T, transmitted by the magnetic field-modulating ring to the inner rotorcRepresenting the torque transmitted by the frequency converter to the inner rotor.
Substituting (3) into (5) can obtain:
assuming the mechanical power P output by the frequency convertercMechanical power P output by magnetic regulating ringsThe ratio of KpAnd then:
from (7), when ΩcAnd omegasSame steering KpIs negative when ΩcAnd omegasWhen the steering is reversed KpIs positive. Will KpNΩs＝-(N-p1)ΩcAnd substituting the load rotation speed into (3):
therefore, when the frequency converter does not output mechanical power, namely when the stator winding of the outer ring is electrified with direct current, omegac0, inner ring rotation speed omegar0＝NΩs/p1. When the rotating magnetic field omega generated by the alternating current of the outer ring stator windingcAnd magnetic regulating magnetic ring omegasWhen the steering is the same, KpNegative, inner ring rotation speed (load rotation speed) lower than omegar0At the moment, the frequency converter feeds electric energy into the power supply; when the rotating magnetic field omega generated by the outer ring stator winding alternating currentcAnd magnetic regulating magnetic ring omegasWhen the direction of rotation is reversed，KpPositive, the inner ring rotation speed (load rotation speed) is higher than omegar0The frequency converter absorbs electrical energy from the power source.
If the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorrIs to K'pCan be expressed as follows:
from (10), when ΩcAnd omegarK 'with same steering'pIs positive when ΩcAnd omegarK 'when the steering directions are opposite'pIs negative. Prepared from K'pp1Ωr＝(N-p1)ΩcSubstituting (4) to obtain the load rotating speed:
from (10) and (11), in the case that the load is connected with the magnetic flux regulating magnetic ring, the rotating magnetic field omega generated when the current of the outer ring stator winding is generatedcWith an inner-loop magnetic field omegarWhen the steering is the same, the frequency converter absorbs electric energy from the power supply, KpPositive, the load speed increases; when the rotating magnetic field omega generated by the outer ring stator windingcWith an inner-loop magnetic field omegarWhen the steering is opposite, the frequency converter feeds electric energy into the power supply, KpNegative, the load speed decreases.
From (9) and (10), it can also be seen that the speed regulation range of the stepless speed change magnetic gear is proportional to the capacity of the frequency converter. When the capacity of the frequency converter is 20% of the capacity of the driving motor, K is not considered to the loss of the driving motorp20 percent and the speed regulating range of the stepless speed changing magnetic gear is about 80 to 120 percent of rated rotating speed. As the speed regulation range of +/-20 percent can meet the speed regulation requirements of most industrial loads, the invention can greatly reduce the capacity of the frequency converter, thereby obviously reducing the speed regulation cost and the harmonic pollution of the frequency converter. Meanwhile, due to the reduction of the capacity of the frequency converter, the frequency converter can be used for a certain capacity rangeThe high-voltage large motor can realize the speed regulation of the motor by adopting a mode of replacing a full-capacity high-voltage frequency converter by a stepless speed change magnetic gear and a 20% capacity low-voltage frequency converter, and the economic benefit of the invention is more obvious in consideration of the great difference of unit prices of the high-voltage frequency converter and the low-voltage frequency converter.
The invention can realize the continuous change of the transmission ratio of the magnetic gear and overcome the defect that the traditional magnetic gear can only provide a fixed transmission ratio. The capacity of the frequency converter used in the invention is about 1/4-1/5 of the capacity of the frequency converter used in the traditional frequency conversion speed regulation, so that the frequency conversion speed regulation cost and harmonic pollution are obviously reduced. The invention can use the low-voltage frequency converter with low unit price and small capacity to replace the high-voltage frequency converter with high unit price and full capacity to realize the frequency conversion speed regulation of the high-voltage large motor within a certain capacity range, and has more obvious economic benefit.
The present invention exemplifies the structural principle of the stepless speed change magnetic gear.
If the load is a large-torque low-rotation-speed load, the magnetic adjusting magnetic ring can be connected with the load, and the driving motor is connected with the inner ring rotor; if the load is a small-torque high-rotation-speed load, the magnetic regulating magnetic ring is connected with the driving motor, and the load is connected with the inner ring rotor. And simultaneously, selecting reasonable number of magnet adjusting blocks and inner rotor pole pairs according to the rotating speed adjusting range required by the load, and determining the initial transmission ratio of the magnetic gear.
Assuming the normal speed regulation range of the load is 500-700rpm, the invention designs a stepless speed change magnetic gear as shown in FIG. 2. The magnetic gear comprises an inner rotor 22 antipole, a magnet adjusting block 27, an outer stator with the number of slots of 60, and windings which are arranged in an upper layer and a lower layer and have 5 antipoles. In fig. 2, 1 is an inner rotor magnetic pole, 2 is a magnet adjusting block, 3 is a stator core, and 4 is a stator winding. The number of slots per phase per pole per stator is 2, and the short distance coefficient is 5/6.
The invention considers the speed regulation range of 500-700rpm, so that the load rotating speed is more suitable to be about 600rpm under the condition of the initial transmission ratio. If the driving motor is connected with the inner ring rotor and the load is connected with the magnetic regulating ring, the driving motor with 4 pairs of poles (the rated rotating speed is about 750rpm) is suitable to be selected according to the load rotating speed 22n0/27 about 600rpm under the condition of the initial transmission ratio. If the load is connected with the inner ring rotor and the driving motor is connected with the magnetic regulating magnetic ring, the 6-pair pole driving motor with the rated rotating speed of about 500rpm is suitable to be selected according to the principle that 27n0/22 is close to 600 rpm.
The invention takes the example that the driving motor is connected with the inner ring rotor, if the driving motor is an asynchronous motor with 4 pairs of poles and the rated slip ratio is 2%, the rated rotating speed is about 735 rpm. When the driving motor is connected with the inner ring rotor, when the stator winding is electrified with direct current, the load rotating speed is about 735 × 22/27 ≈ 599 rpm. When the rotational speed expression is used, (4) can be expressed as follows:
n in the formula (12)sRepresenting the load speed, nrRepresenting the rotational speed of the drive motor, ncRepresenting the rotational speed of the rotating magnetic field of the magnetic gear stator, fcRepresenting the frequency converter output frequency. When the magnetic field steering generated by the current of the outer ring stator winding is the same as the steering (or load steering) of the inner ring rotor, the power grid supplies power to the frequency converter, and fcIs positive; when the magnetic field direction produced by the outer ring stator winding current is opposite to the inner ring rotor direction (or load direction), the frequency converter feeds power to the power supply, fcIs negative. The speed regulation process comprises the following steps:
when the outer ring current is introduced with direct current, the load rotating speed is about 599 rpm; when the load rotation speed is increased, alternating current with a certain frequency is introduced to the outer ring stator winding through the frequency converter according to the phase sequence of A, B, C, and a rotating magnetic field omega generated by the alternating current is generatedcIs turned to omega with the inner ring rotorr(or load steering Ω)s) Similarly, as can be seen from the magnetic gear rotation speed relation (4), the load rotation speed ΩsWill increase by an amount proportional to the energizing frequency.
If the rotating speed of the load is reduced, the outer ring winding can be powered off, at the moment, the magnetic field of the outer ring stator disappears, the electromagnetic coupling is damaged, and the torque of the inner ring rotor cannot be effectively transmitted to the load, so that the rotating speed of the load is reduced, and the rotating speed of the inner ring rotor slightly rises. The rotating speed of the magnetic field generated by the inner rotor magnetic field in the outer ring is shown as (1), and the rotating speed of the working harmonic thereof (m is 1, k is-1) is shown as (2), becauseΩsReduction of sum omegarRise of (2), working harmonic omegacMagnetic field steering and inner ring rotor steering omegar(or load steering Ω)s) Instead, this counter-rotating magnetic field will induce a negative-sequence induced electromotive force in the outer ring stator winding. At the moment, through the adjustment of a control mode, the inverter side of the frequency converter connected with the outer ring stator winding is changed into a rectifying side, the rectifying side connected with a power supply is changed into an inverter side, and the outer ring stator winding is used as a generator to feed power to the power supply. The purpose of adjusting the rotating speed of the load is achieved by controlling the frequency of the current on the inversion side.
According to the design of the scheme, when direct current is introduced into the magnetic gear stator winding, the load rotating speed is about 599 rpm. When the alternating current frequency of the magnetic gear stator winding is continuously adjusted between-44.55 Hz and 45.45Hz, the rotating speed of the load is continuously changed between 500rpm and 700 rpm. From (10), if the capacity of the frequency converter is 20% of the rated capacity of the driving motor, the speed regulation range of the invention is about 479-719 rpm.
Fig. 3 is a flow chart of a method for driving a load using a continuously variable magnetic gear according to a preferred embodiment of the present invention. As shown in fig. 3, the present invention provides a method of driving a load using a continuously variable magnetic gear, the method comprising:
step 301: the method comprises the following steps of establishing a structure from an inner layer to an outer layer: the magnetic gear comprises an inner rotor magnetic pole, a magnetic adjusting magnetic ring, a stator core and a stator winding;
step 302: when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the magnetic poles of the inner rotor, and the load is connected with the magnetic regulating ring;
step 303: when the load is a high-rotating-speed and low-torque type load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor;
step 304: and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
Preferably, the method comprises the following steps:
when the inner rotorThe pole pair number of the magnetic pole is p1The number of iron blocks on the magnetic regulating magnetic ring is N, and the pole pair number p is after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core contains space harmonic, and the pole pair number p of the space harmonicmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± ∞, and the mechanical rotation angular velocity of the magnetic field including each of the space harmonics in the air gap magnetic field on the stator core side is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted; number of pole pairs p of stator winding for constant torque generation2＝N-p1；
The mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
Preferably, when the load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
preferably, when the load is connected with the magnetic poles of the inner rotor, the rotating speed of the load is reduced when the stator core is introduced with positive sequence alternating current; when the phase sequence of the alternating current of the stator winding is changed, the rotating speed of the load is increased;
when the load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
Preferably, the method further comprises the following steps:
the power transmitted to the inner rotor magnetic pole of the magnetic gear by the frequency converter and the magnetic regulating magnetic ring is equal to the sum of the power of the rotating magnetic field of the magnetic regulating magnetic ring and the frequency converter; meanwhile, the output torque of the inner rotor magnetic pole of the magnetic gear is equal to the sum of the electromagnetic torques output by the frequency converter and the magnetic regulating ring, and a power balance formula is obtained:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by the inner ring sub-poles of the magnetic gearsMechanical power, P, representing the output of the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersIndicating the torque, T, transmitted by the magnetic field-regulating ring to the poles of the inner rotorcRepresenting the torque transmitted by the inverter to the poles of the inner rotor.
Preferably, the method further comprises the following steps:
substituting the mechanical angular velocity of the load end into a power balance formula when the load is connected with the inner rotor,
machinery with frequency converter outputPower PcMechanical power P output by magnetic regulating ringsThe ratio of KpAnd then:
from the above formula, when ΩcAnd omegasSame steering KpIs negative when ΩcAnd omegasWhen the steering is reversed KpTo be positive, K ispNΩs＝-(N-p1)ΩcSubstituting a calculation formula of the mechanical angular velocity of the load end when the load is connected with the inner rotor to obtain the mechanical angular velocity of the load end:
from the above formula, when the frequency converter does not output mechanical power, i.e. when the stator winding is supplied with direct current, Ωc0, inner rotor magnetic pole rotation speed omegar0＝NΩs/p1；
For the case of a load connected to the inner rotor, the mechanical power P output by the frequency converter iscMechanical power P output by magnetic regulating rings(i.e., mechanical power output by the drive motor) ratio KpAnd the mechanical angular velocity Ω of the loadrThe calculation formula shows that when the stator winding alternating current generates the rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering (i.e. the driving motor is steered) is the same, KpNegative, the load rotation speed of the inner rotor magnetic pole is lower than omegar0At the moment, the frequency converter feeds electric energy into the power supply; when the stator winding generates a rotating magnetic field omegacAnd magnetic regulating magnetic ring omegasWhen the steering is reversed, KpPositive, the loaded speed of the inner rotor poles is higher than omegar0The frequency converter absorbs electric energy from the power supply;
when the load is connected with the magnetic poles of the inner rotor, when the rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced;
when the load is connected with the magnetic poles of the inner rotor, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from the power supply, so that the rotating speed of the load is increased.
If the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorrIs to K'pExpressed as:
from the above formula, when ΩcAnd omegarK 'with same steering'pIs positive when ΩcAnd omegarK 'when the steering directions are opposite'pIs negative, mixing K'pp1Ωr＝(N-p1)ΩcWhen substituting the load and adjusting the magnetism magnetic ring and being connected, the computational formula of the mechanical angular velocity of load, the load rotational speed is:
for the condition that the load is connected with the magnetic regulating magnetic ring, the mechanical power P output by the frequency convertercMechanical power P output by inner ring rotorr(i.e., mechanical power output from the drive motor) ratio K'pAnd the mechanical angular velocity Ω of the loadsThe calculation formula shows that when the current of the stator winding generates the rotating magnetic field omegacMagnetic field omega with inner rotor magnetic polerK 'when the steering directions (i.e. the driving motors are steered) are the same'pIf the voltage is positive, the frequency converter absorbs electric energy from the power supply, and the rotating speed of the load is increased; when the stator winding generates a rotating magnetic field omegacMagnetic field omega with inner rotor magnetic polerWhen the steering is reversed, K'pAnd when the load is negative, the frequency converter feeds electric energy into the power supply, and the rotating speed of the load is reduced.
When the load is connected with the magnetic regulating magnetic ring, when the rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from the power supply, so that the rotating speed of the load is increased; when the load is connected with the magnetic regulating magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
The invention has been described with reference to a few embodiments. However, other embodiments of the invention than the one disclosed above are equally possible within the scope of the invention, as would be apparent to a person skilled in the art from the appended patent claims.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to "a/an/the [ device, component, etc ]" are to be interpreted openly as referring to at least one instance of said device, component, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
Claims (12)
1. A stepless speed change magnetic gear, which comprises the following components from an inner layer to an outer layer in sequence: the magnetic pole of the inner rotor, the magnetic adjusting magnetic ring, the stator core and the stator winding;
when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the inner rotor magnetic pole, and the load is connected with the magnetic regulating magnetic ring;
when the load is a high-rotating-speed and low-torque load, the driving motor is connected with the magnetic flux regulating magnetic ring, and the load is connected with the magnetic poles of the inner rotor.
2. The magnetic gear of claim 1, comprising:
when the number of pole pairs of the inner rotor magnetic pole is p1The number of the iron blocks on the magnetic adjusting magnetic ring is N, and the pole pair number p is obtained after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core comprises space harmonic waves and poles of the space harmonic wavesLogarithm of pmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± ∞, the mechanical rotation angular velocity of the magnetic field including each harmonic in the space harmonics in the air gap magnetic field on the stator iron core side is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted;
the mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating magnetic ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
3. The magnetic gear of claim 2, when a load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
4. the magnetic gear of claim 3, wherein when a load is connected to the inner rotor poles, the speed of the load decreases when positive sequence alternating current is applied to the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotating speed is increased;
when a load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
5. The magnetic gear of claim 4, further comprising:
obtaining a power balance formula:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by said inner-ring sub-poles of the magnetic gearsRepresenting the mechanical power, P, output by the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersRepresenting the torque, T, transmitted by the magnetic modulating ring to the poles of the inner rotorcRepresenting the torque transmitted by the inverter to the poles of the inner rotor.
6. The magnetic gear of claim 1, further comprising:
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, electric energy is fed into a power supply through a frequency converter, so that the rotating speed of the load is reduced;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased;
when a load is connected with the magnetic regulating magnetic ring, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased;
when the load is connected with the magnetic adjusting magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
7. A method of driving a load with a continuously variable magnetic gear, the method comprising:
the method comprises the following steps of establishing a structure from an inner layer to an outer layer: the magnetic gear comprises an inner rotor magnetic pole, a magnetic adjusting magnetic ring, a stator core and a stator winding;
when the load is a low-rotating-speed and high-torque load, the driving motor is connected with the inner rotor magnetic pole, and the load is connected with the magnetic regulating magnetic ring;
when the load is a high-rotating-speed and low-torque load, the driving motor is connected with the magnetic adjusting ring, and the load is connected with the magnetic poles of the inner rotor;
and determining the number of iron blocks of the magnetic adjusting ring, the number of pole pairs of the magnetic poles of the inner rotor, the number of slots of the stator iron core and the number of pole pairs of the stator winding according to the required rotating speed adjusting range of the load, and obtaining the initial transmission ratio of the magnetic gear.
8. The method of claim 7, comprising:
when the number of pole pairs of the inner rotor magnetic pole is p1The number of the iron blocks on the magnetic adjusting magnetic ring is N, and the pole pair number p is obtained after the outer layer stator winding is electrified2＝N-p1；
The air gap magnetic field at the side of the stator iron core comprises space harmonic waves and the pole pair number p of the space harmonic wavesmk＝|mp1+ kN |, where m ═ 1, 3, 5., ∞; k is 0, ± 1, ± 2, ± 3, ± infinity, and the air gap magnetic field on the stator core side includes space harmonicsThe mechanical rotation angular velocity of the magnetic field of each harmonic is:
the working magnetic field of the magnetic gear is a harmonic wave corresponding to the condition that when m is 1, k is-1, and the number of pole pairs of the working magnetic field is N-p1，ΩrRepresenting the mechanical speed of rotation, omega, of the poles of the rotor in the magnetic gearsThe mechanical rotating speed of the magnetic regulating ring is adopted;
the mechanical angular velocity of the stator magnetic field is assumed to be omegacAnd then:
when the stator winding is energized with DC current, the working magnetic field is stationary and omegac0, the magnetic regulating magnetic ring and the magnetic pole of the inner rotor rotate in the same direction, and omegar/Ωs＝N/p1；
When the stator winding is switched on at a frequency fcWhen the positive sequence alternating current is adopted, the mechanical angular velocity omega of the rotating magnetic field of the stator windingc＝2πfc/(N-p1)。
9. The method of claim 8, when a load is connected with the inner rotor poles, the mechanical angular velocity of the load is:
when the load is connected with the magnetic regulating magnetic ring, the mechanical angular speed of the load is as follows:
10. the method of claim 9, wherein when a load is connected to the inner rotor poles, the speed of the load is reduced when positive sequence ac current is applied to the stator core; the load rotation speed is increased when the phase sequence of the stator winding alternating current is changed;
when a load is connected with the magnetic regulating magnetic ring, the rotating speed of the load is increased when positive sequence alternating current is introduced into the stator core; when the phase sequence of the stator winding alternating current is changed, the load rotation speed is reduced.
11. The method of claim 10, further comprising:
obtaining a power balance formula:
Pr＝Ps+Pc＝TsΩs+TcΩc＝(Ts+Tc)Ωr
wherein P isrRepresenting the mechanical power, P, transmitted to the load by said inner-ring sub-poles of the magnetic gearsRepresenting the mechanical power, P, output by the magnetic field-regulating ringcIndicating mechanical power, T, of the output of the frequency convertersRepresenting the torque, T, transmitted by the magnetic modulating ring to the poles of the inner rotorcRepresenting the torque transmitted by the inverter to the poles of the inner rotor.
12. The method of claim 7, further comprising:
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, electric energy is fed into a power supply through a frequency converter, so that the rotating speed of the load is reduced;
when a load is connected with the inner rotor magnetic pole, when a rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased;
when a load is connected with the magnetic regulating magnetic ring, when a rotating magnetic field generated by the current of the stator winding is the same as the rotation direction of the driving motor, the frequency converter absorbs electric energy from a power supply, so that the rotating speed of the load is increased;
when the load is connected with the magnetic adjusting magnetic ring, when the rotating magnetic field generated by the current of the stator winding is opposite to the rotation direction of the driving motor, the electric energy is fed into the power supply through the frequency converter, so that the rotating speed of the load is reduced.
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|---|---|---|---|
| CN202110275081.6A CN113517801B (en) | 2021-03-15 | 2021-03-15 | Stepless speed change magnetic gear |
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|---|---|---|---|
| CN202110275081.6A CN113517801B (en) | 2021-03-15 | 2021-03-15 | Stepless speed change magnetic gear |
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| US6121705A (en) * | 1996-12-31 | 2000-09-19 | Hoong; Fong Chean | Alternating pole AC motor/generator with two inner rotating rotors and an external static stator |
| CN102868268A (en) * | 2011-07-03 | 2013-01-09 | 余虹锦 | Novel air gap magnetic field electromagnetic modulation permanent magnet motor with double squirrel cage structure |
| CN104393727A (en) * | 2014-12-10 | 2015-03-04 | 哈尔滨工业大学 | Radial magnetic field type electromagnetic planetary gear transmission |
| CN108011484A (en) * | 2017-12-11 | 2018-05-08 | 华中科技大学 | A kind of magnetic gear compound machine |
| CN108512358A (en) * | 2018-04-28 | 2018-09-07 | 天津大学 | The compound multiport wave-activated generator of magnetic gear |
| CN108988598A (en) * | 2018-08-31 | 2018-12-11 | 重庆大学 | Flux modulation formula permanent magnetism vernier motor built in a kind of stator |
| CN112467901A (en) * | 2020-11-12 | 2021-03-09 | 华中科技大学 | Magnetic gear composite direct drive motor and application thereof |
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2021
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| US6121705A (en) * | 1996-12-31 | 2000-09-19 | Hoong; Fong Chean | Alternating pole AC motor/generator with two inner rotating rotors and an external static stator |
| CN102868268A (en) * | 2011-07-03 | 2013-01-09 | 余虹锦 | Novel air gap magnetic field electromagnetic modulation permanent magnet motor with double squirrel cage structure |
| CN104393727A (en) * | 2014-12-10 | 2015-03-04 | 哈尔滨工业大学 | Radial magnetic field type electromagnetic planetary gear transmission |
| CN108011484A (en) * | 2017-12-11 | 2018-05-08 | 华中科技大学 | A kind of magnetic gear compound machine |
| CN108512358A (en) * | 2018-04-28 | 2018-09-07 | 天津大学 | The compound multiport wave-activated generator of magnetic gear |
| CN108988598A (en) * | 2018-08-31 | 2018-12-11 | 重庆大学 | Flux modulation formula permanent magnetism vernier motor built in a kind of stator |
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