A kind of multipole permanent magnet motor pole core structureArt
The present invention relates to a kind of rotor structure for permanent magnet motor, particularly a kind of multipole permanent magnet motor pole core structure, belongs to magneto technical field.
Background technology
There are two kinds of mains frequency standards in the world, i.e. 50Hz frequency and 60Hz frequency standard, no matter generator or power consumption equipment all will meet above two kinds of frequency requirement.According to motor speed formula n=60f/p, the rotating speed n of generator is decided by mains frequency f and motor number of pole-pairs p, because mains frequency is steady state value, motor number of pole-pairs is subject to the restriction of motor volume, motor pole number can not arrange too much, therefore, conventional motors runs up with the speed of 750 turns ~ 3000 turns per minute usually.
Exhaustion along with fossil energy and the pressure under the pressure of environmental pollution, people more and more rely on the development in new forms of energy industry for counsel, such as wind energy, solar energy, oceanic energy, river energy, geothermal energy etc., new forms of energy industry energy relative distribution, encircled energy is inadequate, its rotating speed produced is often very low, the electric energy that generation of electricity by new energy sends often needs to change through commutation inversion, and rectification link requires that the electric energy that generator sends will reach a certain frequency, this just requires that power generator electrode number is abundant, can send the electric energy of certain frequency when could realize low speed.Traditional electric excitation generator number of poles is little, cannot adapt to the needs of this occasion.
At present, in wind-force and river water generating equipment, meet power consumption equipment to generating frequency requirement to meet, or in order to obtain the electric energy of 50Hz frequency or 60Hz frequency, main employing four kinds of patterns at present:
One is at wind turbine or adds a booster engine between the hydraulic turbine and generator, form " wind turbine (hydraulic turbine)+booster engine+generator " system, the slow-speed of revolution that wind turbine or the hydraulic turbine produce is converted to the high rotating speed that generator needs by booster engine, as 750 turns per minute, 1000 turns or 1500 turns.The drawback of this pattern is, after system adds booster engine, efficiency is reduced, adds system configuration, and configuration is complicated, failure rate is high, operating cost is high.
Two is after generator, be connected in series rectifier and inverter, form " wind turbine (hydraulic turbine)+generator+rectifier+inverter " system, the low frequency ac sent by generator becomes direct current, and then DC inverter is become the alternating current of 50Hz frequency or 60Hz frequency by inverter again.System speed is lower in this mode, but the alternating current that rectifier needs generator to send is more than certain frequency (as 12Hz), and this just requires that the number of poles of generator is more, and guarantee rectification effect is good.Rectifier, inverter are made up of expensive high power module in addition, and price is high, poor reliability, adds project cost, and maintenance capacity is large, and operating cost is high.
Three is both be equipped with booster engine in electricity generation system, installs again rectifier, inverter additional simultaneously, forms " wind turbine (hydraulic turbine)+booster engine+generator+rectifier+inverter " system.This system mainly ensures that generator has higher rotating speed, enables the electric energy sent meet the needs of rectifier preferably.This system is the most complicated, and cost is the highest, and maintenance capacity is maximum, but the pattern the most generally adopted at present.
Four is the direct drawing generators of wind turbine or the hydraulic turbine, and the electric energy sent after generating is directly surfed the Net or supplied power consumption equipment, forms " wind turbine (hydraulic turbine)+generator " system, and system runs generating online at the low rotational speed.This is the most succinct, the optimal configuration of one, this system requirements stabilization of speed, the voltage that generator sends and frequency must meet electrical network standard, require that supporting generator will have abundant number of poles, must send the electric energy of 50HZ or 60Hz frequency at the low rotational speed.
Comparatively speaking, permanent magnet generator is easier to realize low speed than traditional electric excitation generator ratio, along with applying of permanent magnet generator, in wind power industry configuration mode gradually by the first with the third pattern to the second schema evolution.In the second pattern, system rotating speed is lower, but the electric frequency sent can not be too low, and General Requirements is at more than 12Hz, otherwise after rectification, waveform is unstable, rectification efficiency is low, and this requires that the generator number of poles of joining is sufficiently many.4th kind of pattern has just started to explore tries out, the electric energy that generator sends in this mode must be 50HZ or 60Hz, in wind power system or river electric generator system, the rotating speed of wind energy conversion system or the hydraulic turbine is very low, if system directly sends the electric energy of 50HZ or 60Hz frequency, require that generator must have a lot of numbers of poles.As when generator speed is at 20 turns per minute, send the electric energy of 50HZ, generator number of poles is necessary for 300 poles, and permanent magnetism magnetic poles many is like this distributed on the little rotor of diameter very difficult, and existing rotor structure for permanent magnet motor is almost difficult to realize.
Summary of the invention
Technology of the present invention is dealt with problems and is: overcome the deficiencies in the prior art, a kind of multipole permanent magnet motor pole core structure is provided, the permanent-magnet steel of this motor can reduce half, the object realizing motor multipole can be easier to, generator can be made to send the electric energy of upper frequency, to meet follow-up direct grid-connected or the grid-connected needs of commutation inversion.
Technical solution of the present invention is: a kind of multipole permanent magnet motor pole core structure, its feature is: many pole cores structure is made up of pole core and magnet steel two parts, in this structure, pole core only lays the magnetic pole of identical polar, as N pole magnet steel or S pole magnet steel, therefore when number of poles is identical, the magnet steel groove of this rotor core reduces half, the distance with magnet steel arc length equidimension is left between two magnet steel, closing by the magnetic line of force, the magnetic pole of another kind of polarity is formed in the place of not opening magnet steel groove, i.e. S pole or N pole, like this by laying the magnet steel of single polarity, N is formed on rotor surface, the magnetic field of S alternating polarity.
Principle of the present invention is: in magnet steel groove, only lay N pole magnet steel or S pole magnet steel, for N pole magnet steel, magnet steel N pole-face is to air gap, the magnetic line of force sends from magnet steel N pole, through motor gas-gap, stator core, turn back through motor gas-gap again, enter rotor core, finally get back to the S pole of magnet steel, form magnetic loop, S pole field is formed there is no the rotor core surface portion of mounting magnetic steel, this polarity being equivalent to magnet steel motor gas-gap dorsad extends to the rotor surface of non-device magnet steel part, makes to form N pole, S pole alternately equally distributed magnetic field on motor gas-gap surface.If what install is S pole magnet steel, will the part of mounting magnetic steel do not had to form N pole field.When generator drive rotor rotation under external force, the alternating magnetic field of N pole, S pole will be formed in stator core, and produce alternation induced potential in the stator coils, form generating voltage, convert the mechanical energy of wind turbine or the hydraulic turbine to electric energy, reach generating object.
The present invention's advantage is compared with prior art: the magnet steel number that generator can be made to lay reduces half, reduce the difficulty of processing of electric machine iron core, decrease magnet steel number of packages, reduce installation difficulty, simplify production technology, improve the utilance of magnet steel, improve production efficiency, improve rotor strength, be conducive to reducing motor volume.Appearing on the market of this generator can simplify new energy resources system configuration mode, promotes the development of new forms of energy industry.
Accompanying drawing explanation
Fig. 1 is a kind of multipole permanent magnet motor pole core structural representation of the present invention.
Fig. 2 is a kind of multipole permanent magnet motor pole core structure magnetic line of force distribution map of the present invention.
As shown in Figure 1, a kind of multipole permanent magnet motor pole core of the present invention, forms primarily of pole core 1, magnet steel 2.
As shown in Figure 2, state and how to form N pole, S pole field on motor surface, the magnetic line of force sends from magnet steel N pole, through motor gas-gap, enter stator core, again turn back motor gas-gap, enter rotor core, arrive the S pole of magnet steel again, form magnetic loop, do not having the part of mounting magnetic steel to form S pole field, make to form N pole, S pole alternately equally distributed magnetic field on motor gas-gap surface.
Embodiment
A kind of multipole permanent magnet motor pole core structure of the present invention, as shown in Figure 1, pole core 1 evenly has magnet steel groove, the groove number of magnet steel groove is identical with the number of pole-pairs of motor, the arc length width of magnet steel groove is substantially identical with institute's arc length of staying between two magnet steel grooves, and magnet steel groove arc length has following formulae discovery:
T＝πD/P
Wherein: the distance of arc length between the arc length width of T-magnet steel groove and two magnet steel grooves, unit: mm
D-rotor external diameter, unit: mm
P-motor pole number
In actual production, according to the distance of magnet steel apart from rotor surface, the arc length width of magnet steel groove can suitably be revised.
Magnet steel 2 is arranged in the magnet steel groove of pole core 1, only installs the magnet steel of single polarity when mounted, namely only installs the magnet steel of N pole relative to motor gas-gap or only installs the magnet steel of S pole.
The present invention had both been applicable to generator iron-core structure, was also applicable to motor iron-core structure, had both been applicable to internal rotor core structure and had also been applicable to outer rotor iron core structure.
The material that pole core 1 applies magnetic property good is in the present invention made.