CN1520005A

CN1520005A - Wheel hub electric motor in frequency conversion mode

Info

Publication number: CN1520005A
Application number: CNA031030475A
Authority: CN
Inventors: 万德鸿
Original assignee: Individual
Current assignee: Individual
Priority date: 2003-01-23
Filing date: 2003-01-23
Publication date: 2004-08-11

Abstract

Based on counter-electromotive force brushless motor in permanent magnetism synchronous trapezoidal wave, structure of wheel hub electric motor is modified in order to run under sine wave principle. Punching silicon steel sheet of outer rotor makes rectangular slots with equal polar distance, and rectangular permanent magnets are embedded in slots. Edges of iron core without punching out slots are straight edges (arc modified as chord). Rectangular edges of permanent magnetism and chords of iron cord constitute polygon structure intersecting to inner circle of outer rotor. Permanent magnetisms as salient poles and iron cores as non-salient pole make air gap of motor distribute unevenly so as to form sinusoidal distribution of magnetism density of permanent magnetism. When adding sinusoidal current of frequency conversion from outside, the motor shows good performances of frequency control.

Description

The frequency conversion wheel hub motor

The present invention relates to a kind of frequency conversion wheel hub motor that is used in the electric motor car, belong to the sinusoidal wave synchronous machine of rare earth permanent magnet, by adding sinusoidal wave frequency conversion (V/F) current controller, directly drive hub motor walking.

At present, existing dc brushless motor also belongs to a kind of of permagnetic synchronous motor, and its back-emf is a trapezoidal wave, passes to the square wave power operation, and this is the brushless electric machine that generally uses on present electric bicycle and the battery-operated motor cycle.The ubiquitous shortcoming of this motor is: 1. that adopts is square wave power or is the square wave drive pattern, motor windings sequential loop energising according to certain rules, armature field is divided into several magnetic field states in 360 °, magnetic field size direction is constant under every kind of state, so motor operation one-period armature field is the noncontinuity great-jump-forward, torque ripple when easily causing low speed high torque brings significantly uncomfortable to the bicyclist ^[1]2, need position transducer, too many from motor internal position transducer lead-out wire, easily introduce and disturb, especially under the environment mal-condition, use, can reduce reliability ^[2]3, the rare earth material of Shi Yonging is many, because of sticking garden week in the external rotor with tile-shaped magnet, process numerous, manufacturing cost is high, used rare earth material accounts for 1/2 of motor total cost ^[3]

The purpose of this invention is to provide a kind of have good low cruise characteristic, the frequency control motor of position-sensor-free, high performance-price ratio.

Implementation method of the present invention is: in the punching of external rotor electric machine iron core (1), punching out such as has at the rectangular channel of pole span, every groove embeds a rare-earth permanent magnet (2), and keep the permanent magnet polarity direction all towards axis direction, cause that permanent magnet is a salient pole in the air gap, iron core is a non-salient pole, and the tie point of salient pole and non-salient pole rectangular edges is met on the interior garden of external rotor, becomes polygonized structure; Shown in accompanying drawing 1,2.And the jet-bedding number of outer rotor iron core (1), press garden girth in the iron core divided by half of number of poles, the width of jet-bedding is the right chord length of this groove arc, be the long limit of permanent magnet rectangle, and the vertical range of string at the bottom of the rectangle jet-bedding equals the minor face of permanent magnet, and the always folded thickness of core stamping equals the length of permanent magnet.

Rare-earth permanent magnet (2) is made and is just embedded in the motor outer rotor iron core jet-bedding, and require permanent magnet to be close to iron core slot, can not adopt any NULL to separate two sides of permanent magnet and iron core slot, permanent magnet and jet-bedding should adopt transition size fit tolerance in the production.And in the permanent magnet motor design of prior art, embed nonmagnetic substance to the two sides of external rotor punching groove, with nonmagnetic substance (mostly being bakelite plate) permanent magnet and two sides of jet-bedding iron core are separated ^[4]

In the frequency conversion wheel hub motor, the groove number of the number of magnetic poles of rare-earth permanent magnet (2) and motor stator (3) is a fractional slot winding ^[5], as three-phase 24 grooves, 28 utmost points; 36 grooves, 40 utmost points; Five phases, 20 grooves, 18 utmost points; 40 grooves, 36 utmost points etc.

Should be on motor outer rotor the same polarity N (or S utmost point) of the rare-earth permanent magnet that embeds, all towards the garden heart (the being stator core) direction of motor, then forming permanent magnet is the N utmost point (or S utmost point), and adjacent punching iron core is the S utmost point (or N utmost point), iron core is a non-salient pole, and permanent magnet is a salient pole.

For reducing slot effect, improve electric efficiency, simplify wire winding, improve work efficiency, in the example of motor of the present invention, should adopt fractional-slot armature winding ^[5], promptly the groove number of the number of magnetic poles of rare-earth permanent magnet (2) and motor stator (3) is a fractional slot winding.

The present invention is further described below in conjunction with drawings and Examples.

Fig. 1 is the external rotor and the inner-stator iron core jet-bedding plan view of three-phase 24 grooves 28 utmost point fractional-slots design, 1. outer rotor iron cores, 2. rare-earth permanent magnets, 3. motor stators among the figure.

Fig. 2 is the external rotor and the inner-stator iron core jet-bedding plan view of five phases, 20 grooves, 18 utmost point fractional-slots design, 1. outer rotor iron cores, 2. rare-earth permanent magnets, 3. motor stators among the figure.

Fig. 3 amplifies single rectangular shaped poles section diagrammatic sketch.

Fig. 4 and Fig. 5 are 150W electric bicycle three-phase 40 utmost points (external rotor punching figure) and 36 grooves (internal stator punching figure).

Fig. 6 and Fig. 7 are automobile-used three-phase 40 utmost points of 500W electric motorcycle (external rotor punching figure) and 36 grooves (internal stator punching figure).

In Fig. 1 and Fig. 2 as can be seen: every square rare-earth permanent magnet is that equal intervals is evenly distributed in the external rotor punching iron core slot, and the width of permanent magnet rectangle (being the core stamping width) equates with the chord length of not going out breach.

In monolithic permanent magnet enlarged drawing 3, can obviously find out: rectangle permanent magnet (or being salient pole) surface right stator midline gap (air gap between stator and rotor) minimum, and the permanent magnet both ends of the surface are to gap, stator core place (air gap between stator and rotor) maximum, and non-salient pole also is a same case, form each magnetic pole (comprising salient pole and non-salient pole) be uneven to the air gap between stator ^[6], therefore can obtain the permanent magnetism magnetic flux density waveforms for sinusoidal wave.

The embodiment of the invention is as follows:

Model machine 1, employing three-phase 36 grooves 40 utmost points are manufactured experimently a 150W, the battery-powered electric bicycle of 36V direct current wheel hub type motor, and its external rotor Fig. 4 and internal stator are shown in Figure 5.Be directly with 30 in Fig. 4 ^#After the steel car system again the line cutting processing finish; Fig. 5 by 0.5mm thickness silicon steel plate stacking after, the warp cutting processing, also must join in addition axle sleeve, axle, bearing, end cap, winding, lead-out wire and rare-earth permanent magnet (NaFeB) assembling.Photo 2 is external rotor and the internal stator of model machine after taking apart, the pitch Y=1 of armature winding, it is concentrating coil of coiling on each tooth, the integer sheave hub motor that generally uses on this coiling mode and the existing electric bicycle, compare as three-phase 12 utmost points, 36 grooves and three-phase 16 utmost points 48 grooves, because garden week in the external rotor of integer groove, adopts 12 or 16 thick watt shape (palpus warp cutting processing is finished) rare-earth permanent magnets (NaFeB) of 3mm to stick, the pitch Y=4 of winding, i.e. the 1st to the 4th groove embedding around.

The major advantage of model machine is:

(1), identical rare-earth permanent magnet, rectangle is compared with a watt shape, and is not only easy to process, waste material not, and the motor of every equal volume and capacity can make the rare earth permanent-magnetic material consumption reduce, cost reduces about 40%; This is not only because this model machine has adopted the rectangle permanent magnet, make to add man-hour watt shape waste of material is few, and because of the design of motor multipolarization also be the effective means that reduces cost ^[7]

(2), short because of winding pitch, the cross-line between stator core slot and the groove is short, not only can every saves copper cash about 30%, and because after the cross-line shortening, identical winding conducting wire total length is also short, motor internal resistance, leakage reactance reduce, help increasing motor and exert oneself, improve sensitivity and efficient.

Photo 1 is the output waveform (counter potential waveform) of model machine under generating state, find out from the photo sine wave curve, this curve has approached sine wave, and some flat-top phenomenons have appearred in negative half-wave, be because model machine for simplifying trial process, has adopted simple Vehicle Processing, core magnetic pole (non-salient pole) is not polygon but garden shape, therefore the sinusoidal negative wave (this is non-existent aborning) of flat-top just occurred, also provable polygon non-uniform gap magnetic is close simultaneously can form sinusoidal wave back-emf.

Photo 2 is the structure of model machine after taking apart, and permanent magnet is to wait pole span to embed in the external rotor on the garden separately as can be seen from photo, and equally distributed, and stator winding is that fractional-slot is concentrated the coiling mode.Model machine 1 is 150W, 36V electric bicycle usefulness, and its testing efficiency reaches more than 80%; And weight only is about 80% of existing brushless electric machine, the existing brushless electric machine attached sheet 2 of contrast.

Model machine 2 is three-phase 40 utmost point 500W.36V electric motorcycle wheel hub type frequency control motors, has good external characteristic (with reference to attached sheet 3), and its physical dimension iron core is shown in accompanying drawing 6 and accompanying drawing 7.

By the trial-production and the test of model machine, illustrate and adopt frequency conversion wheel hub motor of the present invention can reach sinusoidal wave back-emf, and have good holding property of frequency control.

Implementing the present invention can carry out in general motor manufacturer.

Firsthand information provided by the invention has: one, 4 pages in advanced development punching drawing (accompanying drawing 4,5,6,7); Two, photo is 2; Three, test parameter and curve are 3 pages; Four, the reference copy is 23 pages.

Claims

1, a kind of frequency conversion wheel hub motor, it belongs to the permagnetic synchronous motor field, according to brushless, permanently trapezoidal wave structure, changing a social system is that sinusoidal wave principle is moved, and method is to utilize the external rotor silicon sheet core, punching out such as has at the rectangular channel of pole span, embed the rectangle permanent magnet in the groove, cause the permanent magnetism magnetic of motor gas-gap Sine distribution close, feed sinusoidal wave frequency conversion (V/F) electric current, can obtain good holding property of speed governing, it is characterized in that:

A, in the punching of outer rotor iron core (1), punching out such as has at the rectangular channel of pole span, every groove embeds a rare-earth permanent magnet (2), and keep the permanent magnet polarity direction all towards axis direction, cause that permanent magnet is a salient pole in the air gap, iron core is a non-salient pole, and the tie point of salient pole and non-salient pole rectangular edges is met on the interior garden of external rotor, becomes polygonized structure;

The jet-bedding number of b, outer rotor iron core (1), press garden girth in the iron core divided by half of number of poles, jet-bedding is wide to be the right chord length of this groove arc, be the long limit of permanent magnet rectangle, and the vertical range of string at the bottom of the rectangle jet-bedding equals the minor face of rectangle permanent magnet, and the total folded thickness of core stamping equals the length of permanent magnet.

2, frequency conversion wheel hub motor according to claim 1 is characterized in that: rectangle rare-earth permanent magnet (2) is made and is just embedded in the motor outer rotor iron core jet-bedding, and requires permanent magnet to be close to iron core slot.

3, frequency conversion wheel hub motor according to claim 1 is characterized in that: the groove number of the number of magnetic poles of rare-earth permanent magnet (2) and motor stator (3) is a fractional slot winding, as three-phase 24 grooves, 28 utmost points; 36 grooves, 40 utmost points; Five phases, 20 grooves, 18 utmost points; 40 grooves, 36 utmost points.