Disclosure of Invention
The invention aims to solve the problem that the existing direct-drive wave power generation system is poor in power generation quality, and provides a double-mover double-winding flat plate type linear generator based on a magnetic field modulation principle.
The invention relates to a double-rotor double-winding flat plate type linear generator based on a magnetic field modulation principle, which comprises a shell, a double-winding stator, a permanent magnet rotor, a modulation rotor, a permanent magnet rotor output end and a modulation rotor output end, wherein the shell is provided with a plurality of permanent magnet rotor windings;
the double-winding stator is symmetrically fixed on the upper inner surface and the lower inner surface of the casing by taking an axis plane as a symmetry plane, a permanent magnet rotor is arranged inside the double-winding stator, and a modulation rotor is arranged between the permanent magnet rotor and the double-winding stator;
the left end of the permanent magnet rotor is in sliding connection with the modulation rotor through a second guide rail, and the right end of the permanent magnet rotor extends out of the right end cover of the casing to serve as the output end of the permanent magnet rotor and is also in sliding connection with the modulation rotor through a third guide rail;
the modulation rotor is a symmetrical structure taking an axis plane as a symmetrical plane; two ends of the modulation rotor respectively extend out of end covers at two sides of the shell, wherein a right extending part is in sliding connection with the permanent magnet rotor and a right end cover of the shell through a third guide rail and a fourth guide rail; the left extending part serves as a modulation rotor output end, and the modulation rotor output end is respectively connected with the casing left end cover and the permanent magnet rotor in a sliding mode through a first guide rail and a second guide rail;
a radial air gap L1 exists between the modulation rotor plane and the double-winding stator plane; a radial air gap L2 exists between the modulation rotor plane and the permanent magnet rotor plane; and the axial symmetry planes of the output end of the modulation rotor and the output end of the permanent magnet rotor are superposed.
Preferably, the double-winding stator is composed of a stator core, a first stator winding and a second stator winding; the first stator windings are symmetrically distributed by taking the axial plane as a symmetry plane, and m is arranged on both symmetrical sides1Phase stator winding, when the first stator winding is energized with m1When alternating current, p moving along the axial direction is formeds1Pole pair number armature field, m1、ps1Is a positive integer; the second stator windings are symmetrically distributed by taking the axial plane as a symmetrical plane, and the symmetrical two sides are m2Phase stator winding, when the second stator winding is energized with m2When alternating current, p moving along the axial direction is formeds2Pole pair number armature field, m2、ps2Is a positive integer.
Preferably, the permanent magnet rotor is of a symmetrical structure with an axis plane as a symmetrical plane, and the number of pole pairs at two symmetrical sides is pPM,pPMIs a positive integer; the permanent magnet rotor is composed of a permanent magnet rotor core and 4pPMEach permanent magnet unit is formed; 2p on each sidePMThe permanent magnet units are uniformly distributed and arranged along the axial direction, 2pPMThe permanent magnet units are fixed on the upper surface and the lower surface of the permanent magnet rotor core, and the magnetizing directions of two adjacent permanent magnet units are opposite; the magnetizing direction of the permanent magnet units is parallel magnetizing.
Preferably, the modulation rotor is a symmetrical structure with an axial plane as a symmetrical plane and is composed of 2pmA magnetic conductive block, 2pmA non-magnetic conductive block and a rotor support, pmIs a positive integer; the rotor supports on each side are arranged in a staggered mode in the axial directionmA magnetic conductive block and pmA non-magnetic conductive block.
While satisfying the condition ps1=|kpPM+jpmI and ps2=kpPMWhere k is a positive integer and j is an integer.
Preferably, the magnetic conduction block is made of soft magnetic composite materials, silicon steel sheets, solid iron or soft magnetic ferrite.
The invention has the advantages that: the double-mover double-winding flat plate type linear generator based on the magnetic field modulation principle is provided with two independent movers, and the thrust and the speed of the two movers are completely independent; meanwhile, the motor is of a symmetrical structure, and unilateral magnetic tension does not exist in the motor. Therefore, in an actual wave power generation system, no matter how one rotor moves along with waves, the amplitude and the frequency of the voltage generated by the generator can be kept constant by effectively controlling the other rotor, and the power generation quality of the power generation system and the stability of the system are further improved.
Detailed Description
The present invention will be described in detail with reference to fig. 1 to 4. Fig. 1 is a schematic structural diagram of an embodiment of a double-mover double-winding plate type linear generator based on a magnetic field modulation principle.
The double-rotor double-winding flat plate type linear generator based on the magnetic field modulation principle comprises a shell 4, a double-winding stator 5, a permanent magnet rotor 7, a modulation rotor 6, a permanent magnet rotor output end 10 and a modulation rotor output end 1;
the double-winding stator 5 is symmetrically fixed on the upper and lower inner surfaces of the casing 4 by taking an axial plane as a symmetry plane, a permanent magnet rotor 7 is arranged inside the double-winding stator 5, and a modulation rotor 6 is arranged between the permanent magnet rotor 7 and the double-winding stator 5
The left end of the permanent magnet rotor 7 is connected with the modulation rotor 6 in a sliding manner through the second guide rail 3, and the right end of the permanent magnet rotor 7 extends out of the right end cover of the casing 4 to serve as the output end 10 of the permanent magnet rotor and is also connected with the modulation rotor 6 in a sliding manner through the third guide rail 8;
the modulation rotor 6 is a symmetrical structure with an axis plane as a symmetrical plane; two ends of the modulation rotor 6 respectively extend out of end covers at two sides of the shell, wherein the right extending part is in sliding connection with the permanent magnet rotor 7 and a right end cover of the shell 4 through a third guide rail 8 and a fourth guide rail 9; the left extending part serves as a modulation rotor output end 1, and the modulation rotor output end 1 is respectively connected with a left end cover of a casing 4 and a permanent magnet rotor 7 in a sliding manner through a first guide rail 2 and a second guide rail 3;
a radial air gap L1 exists between the plane of the modulation rotor 6 and the plane of the double-winding stator 5; a radial air gap L2 exists between the plane of the modulation rotor 6 and the plane of the permanent magnet rotor 7; the axial symmetry planes of the modulation rotor output end 1 and the permanent magnet rotor output end 10 are superposed.
The double-winding stator 5 consists of a stator core 5-3, a first stator winding 5-1 and a second stator winding 5-2; the first stator winding 5-1 is symmetrically distributed by taking the axial plane as a symmetry plane, and the two symmetrical sides are m1Phase stator winding ofThe first stator winding 5-1 is provided with m1When alternating current, p moving along the axial direction is formeds1Pole pair number armature field, m1、ps1Is a positive integer; the second stator winding 5-2 is symmetrically distributed by taking the axial plane as a symmetry plane, and the two symmetrical sides are m2Phase stator winding, when the second stator winding 5-2 is provided with m2When alternating current, p moving along the axial direction is formeds2Pole pair number armature field, m2、ps2Is a positive integer.
The permanent magnet rotor 7 is a symmetrical structure taking an axis plane as a symmetrical plane, and the number of pole pairs at two symmetrical sides is pPM,pPMIs a positive integer; the permanent magnet rotor 7 is composed of permanent magnet rotor iron cores 7-2 and 4pPMEach permanent magnet unit 7-1; 2p on each sidePMThe permanent magnet units 7-1 are uniformly distributed and arranged along the axial direction, 2pPMThe permanent magnet units 7-1 are fixed on the upper surface and the lower surface of the permanent magnet rotor iron core 7-2, and the magnetizing directions of the two adjacent permanent magnet units 7-1 are opposite; the magnetizing direction of the permanent magnet unit 7-1 is parallel magnetizing.
The modulation rotor 6 is a symmetrical structure with an axial plane as a symmetrical plane and is composed of 2pmEach magnetic conductive block 6-1, 2pmP is composed of a non-magnetic conductive block 6-2 and a rotor bracket 6-3mIs a positive integer; the rotor supports 6-3 on each side are arranged in a staggered way p along the axial directionmEach magnetic conductive block 6-1 and pmAnd a non-magnetic conductive block 6-2.
While satisfying the condition ps1=|kpPM+jpmI and ps2=kpPMWhere k is a positive integer and j is an integer.
The magnetic conduction block 6-1 is made of soft magnetic composite material, silicon steel sheet, solid iron or soft magnetic ferrite.
For the purpose of illustrating the working principle of the present invention, the following description is made with reference to fig. 1 to 4.
The number of pole pairs on two sides of the permanent magnet rotor is pPMAt a velocity of VPMInitial phase angle of thetaPMThen the permanent magnet motive force F moving along the axis direction is formed by the permanent magnet rotorPM(θ, t) can be expressed as
In the formula Fk-each subharmonic magnetomotive force amplitude;
k is the harmonic frequency of the permanent magnet magnetomotive force;
theta-mechanical angle;
t is time.
Let the number of the magnetic conduction blocks at both sides of the modulation rotor be pmAt a velocity of VmInitial phase angle of thetamThe spatial specific permeance λ (θ, t) of the modulation mover with time can be expressed as
In the formula of0、λi-the specific magnetic conductance amplitude of each harmonic;
i-the harmonic to permeance number.
The permanent magnetic field which is generated by the magnetomotive force of the permanent magnet and moves along the axial direction under the action of the modulation rotor can be expressed as
In the formula BkMagnitude of natural harmonic magnetic field, and Bk=Fkλ0;
Bk,i-modulating the harmonic magnetic field amplitude, and Bk,i=Fkλi。
As can be seen from the formula (3), the permanent magnet rotor and the modulation rotor generate two types of magnetic fields under the combined action. The first kind is natural harmonic magnetic field, and the magnetic field features its magnetic field pole pair number and speed the same as that of the magnetic motive force of the permanent magnet rotor, and amplitude Bk. The second type is a modulated harmonic magnetic field which is characterized in that the number of magnetic field pole pairs is related to the number of pole pairs of a permanent magnet rotor and the number of magnetic conduction blocks in the modulated rotor, and the magnetic field speed is also related to the second type of the permanent magnet rotor and the modulated rotorThe velocity of the magnetic field is related, the amplitude of the magnetic field is Bk,iThe following are:
pk,j=|kpPM+jpm| (4)
j=0,±1,±2,... (6)
in the formula pk,j、Vk,jModulating the pole pair number and the synchronous speed of the harmonic magnetic field.
According to the principle of electromechanical energy conversion, only when the pole pair number and the speed of the two magnetic fields are the same, constant thrust can be generated, and therefore electromechanical energy conversion is achieved. The second stator winding 5-2 is thus designed by the winding arrangement to generate an armature magnetic field with the same number of pole pairs and speed as the modulated harmonic magnetic field. Then, the second stator winding 5-2, the modulating mover and the permanent magnet mover constitute a double-mover linear motor of the magnetic field modulation type. In this case, the electromagnetic thrust acting on the modulating mover is equal to the sum of the electromagnetic thrusts acting on both the stator and the permanent magnet mover, and their electromagnetic thrusts are in opposite directions. Meanwhile, the thrust relations between the modulation rotor and the permanent magnet rotor and between the modulation rotor and the second stator winding 5-2 are always in a certain proportion. Further, the armature magnetic field speed generated by the second stator winding 5-2 is equal to the modulation harmonic magnetic field speed, and therefore, the speed can be adjusted with reference to equation (5). Therefore, under the interaction of the second stator winding 5-2, the modulation rotor and the permanent magnet rotor can only realize speed decoupling, but the thrust between the modulation rotor and the permanent magnet rotor is still coupled. In practice, if only one set of windings (the second stator winding 5-2) is used, the voltage delivered by the windings will be extremely unstable due to the uncertainty of the wave motion.
The second stator winding 5-2 can generate an armature magnetic field with the same pole pair number and speed as the natural harmonic magnetic field by further designing the winding arrangement. The second stator winding 5-2 and the permanent magnet mover then constitute a permanent magnet synchronous linear motor. At this time, the second stator winding 5-2 acts only with the permanent magnet mover to generate thrust, but not with the modulation mover. Further, since the number of pole pairs of the armature magnetic field generated by the second stator winding 5-2 and the second stator winding 5-2 is different, no thrust force is generated therebetween, in other words, no influence is generated therebetween. Therefore, through the interaction of the second stator winding 5-2 and the permanent magnet rotor, the thrust decoupling of the modulation rotor and the permanent magnet rotor can be realized.
As can be known from the analysis, the electromagnetic thrust on the modulation rotor is only related to the second stator winding 5-2, and the modulation rotor speed is related to the armature magnetic field of the second stator winding 5-2 and the speed of the permanent magnet rotor; the electromagnetic thrust on the permanent magnet rotor is not only related to the second stator winding 5-2, but also influenced by the second stator winding 5-2, and the speed of the permanent magnet rotor is only the same as the armature magnetic field speed of the second stator winding 5-2. Therefore, for a double-mover double-winding plate type linear generator based on the magnetic field modulation principle, the thrust and the speed of the modulation mover are completely independent of the thrust and the speed of the permanent magnet mover. In addition, the motor is of a symmetrical structure, and unilateral magnetic pull force does not exist in the motor.
In practical applications, the modulator mover is connected to a wave gearing, so that the motion of the modulator mover is highly random. At the moment, the thrust and the speed of the permanent magnet rotor are effectively controlled through the second stator winding 5-2, so that the speed of an armature magnetic field of the second stator winding 5-2 is always kept constant, the amplitude and the frequency of voltage generated by the double-rotor double-winding cylindrical linear generator based on the magnetic field modulation principle are always kept constant, and the power generation quality of the whole power generation system is remarkably improved.
Specifically, the number of pole pairs of the permanent magnet mover in fig. 1 is 6, and the number of the magnetic conductive blocks in the modulation mover is 10. From equation (4), a series of modulated harmonic magnetic fields are generated in the air gap. Among these modulated harmonic magnetic fields, the amplitude of the corresponding modulated harmonic magnetic field is maximum when k is 1 and j is-1, that is, the amplitude of the 4-pole pair magnetic field is maximum in the modulated harmonic magnetic field. Therefore, the second stator winding 5-2 can generate 4 pairs of pole armature magnetic fields by the winding arrangement design, as shown in fig. 3 (the first stator winding 5-1 is symmetrically distributed with the axial plane as a symmetry plane, the winding arrangement at two symmetrical sides is the same, and the winding arrangement at any side is shown in the figure). And the speed of the armature magnetic field generated by the second stator winding 5-2 is controlled to be the same as the speed of the 4-antipodal modulation harmonic magnetic field, so that electromechanical energy conversion is realized by the second stator winding 5-2, the modulation rotor and the permanent magnet rotor.
In this case, as can be seen from equation (3), a series of natural harmonic magnetic fields are generated in the air gap, and of these natural harmonic magnetic fields, when k is 1, the amplitude of the corresponding natural harmonic magnetic field is the largest, that is, the amplitude of the natural harmonic magnetic field generated by the permanent magnet mover is the largest for 6 pairs of poles. Therefore, the second stator winding 5-2 can generate 6 pairs of pole armature magnetic fields by the winding arrangement design, as shown in fig. 4 (the second stator winding 5-2 is symmetrically distributed with the axial plane as a symmetry plane, the winding arrangement at two symmetrical sides is the same, and the winding arrangement at any side is shown in the figure). And the speed of the armature magnetic field generated by the second stator winding 5-2 is controlled to be the same as the speed of the 6 antipodal natural harmonic magnetic field, so that the electromechanical energy conversion can be realized by the second stator winding 5-2 and the permanent magnet rotor.
In addition, since the number of pole pairs of the armature magnetic field generated by the second stator winding 5-2 and the second stator winding 5-2 are different (one is 4 pairs of pole armature magnetic fields and the other is 6 pairs of pole armature magnetic fields), no thrust is generated therebetween according to the principle of electromechanical energy conversion. In other words, they do not affect each other.
The final effect is equivalent to that the second stator winding 5-2, the modulation rotor and the permanent magnet rotor are a double-rotor motor; and the second stator winding 5-2 and the permanent magnet mover are equivalent to a conventional permanent magnet synchronous linear motor. In this way, the speed decoupling of the modulation rotor and the permanent magnet rotor can be realized through the control of the second stator winding 5-2, but the thrust of the modulation rotor and the permanent magnet rotor is coupled (not independent); and thrust decoupling between the modulation rotor and the permanent magnet rotor can be realized by further controlling the second stator winding 5-2. Therefore, in practical application, the second stator winding 5-2 realizes effective control on the permanent magnet rotor, and the voltage amplitude and the frequency emitted by the second stator winding 5-2 can be ensured to be constant even under the condition of modulating the random variable speed motion of the rotor, so that the power generation quality of the whole power generation system is improved, and the stability of the system operation is also improved. In addition, the motor is of a symmetrical structure, and unilateral magnetic pull force does not exist in the motor.