DE4218888A1 - Commutator machine with stator poles facing magnetised rotor segments - has oppositely wound pairs of pole pieces broadened into faces aligned with radially magnetised segments of external rotor - Google Patents

Abstract

The core (11) of the stator (10) is divided by radial grooves (12) into identical pole pieces (15) whose faces (16) lie adjacent to those (17) of permanent magnets (18) arranged with alternate radial magnetisation on the inside of the external rotor (19). The width (d) of the gap (21) between adjacent magnets corresponds to that (b) of the groove between the adjacent stator pole faces, two of which are aligned with each magnet. The adjacent pairs of pole pieces are wound (22,23) in opposite directions. ADVANTAGE - Machine can be operated esp. with three phase current derived at low cost from DC voltage.

Description

The invention relates to an electrical machine as it is specified in the preamble of claim 1.

Such electrical machines are particularly adequate known as electric motors and work according to the be known principle, one using the winding arrangement magnetic rotating field generated in the stator Permanent magnet provided rotor or rotor synchronously follows. Are such engines with a match voltage operated, it is necessary the same voltage into an electronic circuit convert two-phase three-phase current. The elec tronics for generating the three-phase pulses supplied which is the speed of the motor proportional to the voltage Show.  

Known electric motors based on sinusoidal three-phase currents are coordinated, the electronics for generating the Three-phase current with a very large amount of circuitry so that they are approximately sinusoidal generated against three-phase current. This is a complex elek tronic circuit required, the high frequency works and enables the sine with a pulse width control.

Based on this state of the art, the inventor the task based on another electrical measure Provide machines of the type mentioned, the especially with one with little effort DC voltage generated three-phase is operable.

This object is achieved with an electrical Machine of the type mentioned by the character nenden features of claim 1 solved.

The inventive design of the pole faces Stator and the reaction part, which is chosen so that the pole faces on the stator cover the entire surface Pole surfaces can be arranged on the reaction part achieved a sharp magnetic edge on the reaction part with a sharp pole face edge on the stator overlaps, causing a very sharp increase or decrease the voltage in the windings is caused when the elec trical machine is operated as a generator. Here who due to the very steep increases or decreases in the span generated their rectangular pulses, as in experiments with an electrical machine operated as a generator could be demonstrated according to the invention.

Since the electrical machine according to the invention in the Genera door operation supplies a square wave voltage, it can vice versa  returns with a three-phase supply the square-wave voltage can be operated without the round engine running or its efficiency is reduced because the voltage differences between the applied and the generated square-wave voltage of the motor largely be compared.

The basic idea of the present invention is therefore in that instead of the usual adjustment of the rotation current or the electrical working as a motor Machine applied voltage to a sine wave electrical machine itself is designed so that it with a rectangular three-phase current or with a rectangular chip can be operated as a motor. This adjustment will through the mutually assigned pole faces on the stator and reached at the reaction part, whereby sharp magnetic Form edges that have a very steep rise or fall the generated voltage and thus the corresponding rectangle cause pulse.

The electrical machine according to the invention can therefore be as a rotating motor, as a generator and also as a linear insert motor.

The embodiments of the invention according to claims 2 up to 4 are particularly advantageous for a motor with a two-phase, 90 ° phase ver pushed rectangular three-phase current can be operated.

Appropriate developments of the invention are in the Claims 5 to 7 described.

To generate the three-phase current by means of the supply Circuit necessary impulses are therefore from Im  pulse generators supplied, the relative movement between Detect stator and reaction part. These impulses can in addition to controlling the supply circuit for rotation power generation at the same time for positioning the location between stator and reaction part and to the direction of motion detection, i.e. with rotating rotors and generators can be used to detect the direction of rotation.

Due to the pulse generator arranged according to the number of poles 90 ° phase-shifted impulses simple way.

To optimize the electrical machine accordingly the necessary operating conditions are to be made possible the embodiments of the invention according to claims 8 and 9 are provided.

The pulse generators are in a neutral position Windings arranged at an angle that is a phase corresponds to an angle of 90 °. In this arrangement, the Motor in clockwise and counterclockwise rotation, which is caused by reversing the Phases is reached, the same speed. This one however, position is not ideal. Rather, a demonstration setting by the adjustability of the pulse generator enables better results. Also lets the engine here even with different loads by optimizing.

Another advantageous embodiment of the invention is described in claims 10 and 11. Besides the before preferred use of Hall sensors for the pulse generator however, it is also possible to use other pulse generators, such as, for. B. light barriers or induction sensors.  

The use of separate control magnets that match the Hall sensors work together has the advantage that the pulse encoder arrangement independent of the working magnets on the reac tion part can be arranged.

To ensure a good braking effect even at low speeds achieve, the embodiment according to claim 12 is before seen.

The electrical machine according to the invention can be in a variety of versions, especially as Insert electric motor. If care is taken that high numbers of poles are reached, e.g. B. 6, 18 or 24 poles, can have short magnetic refluxes and a result Turing high magnetic flux density can be achieved. Here due to large iron cross sections in the back of the Sta tors and the reaction part are omitted, whereby a significant weight saving is achieved.

Particularly preferred engine variants, all according to the work according to the same inventive principle, point as a reak tion part either a 6-pin conventional interior rotor, an 8-pole disc rotor, an 18-pole large internal rotor with short axial construction length, a 24-pin external rotor or a 4-pin elongated external rotor. Motors with multi-pole, Large runners are characterized by slow speed and high torques, so that in the set to otherwise required reduction gears can be waived. This will also cause the otherwise Gearboxes avoided losses and noise.

Another surprising feature of one as an engine operated electrical machine according to the invention be  is that she is a star when unstressed kes holding torque, which for many applications is advantageous.

In addition, electrical machines that are the result of their design a low speed and a high speed Have moment, advantageously as a wind genera insert gates.

A particularly preferred use of the invention electrical machine is in claims 13 and 14 be wrote.

The integrated arrangement of the electrical machine as Drive motor in a vehicle wheel enables one such drive motor in both two-wheeled as well to be used in four-wheel vehicles. Special purpose It is moderate if such vehicles as four-wheel drive driven vehicles are designed, as this means Ge drives and with four-wheel vehicles also on otherwise required differentials can be dispensed with.

The invention is described below, for example, with reference to Drawing explained in more detail; shows in the drawing

Fig. 1 is a plan view of a portion of an electrical machine, the rotor is formed as a motor with a 24-pole outside,

Fig. 2 shows an enlarged detail from FIG. 1,

Fig. 3 is a simplified, schematic illustration of a motor made as electrical machine formed with a supply circuit,

Fig. 4 is a timing diagram of the motor of Fig. 3,

Fig. 5 shows a section through an inventive external rotor motor, which is integrated in a wheel of a motor vehicle, and

Fig. 6 shows a section through an inventive internal rotor motor.

In the different figures of the drawing are each other corresponding components with the same reference numerals net.

The electrical machine partially shown in FIG. 1 is designed as an external rotor motor with a stator 10 , which has a stator core 11 with a total of 48 slots 12 for receiving two winding arrangements 13 , 14 . Pole shoes 15 are formed between the grooves 12 , the circumferentially arranged pole faces 16 corresponding pole faces 17 of which serve as working magnets 18 permanent magnets. The working magnets are arranged on a carrier 19 of an external rotor 20 serving as a reaction part.

The pole faces of the working magnets 18 , of which 24 are arranged on the outer rotor 20 alternately with opposite polarity, are the pole faces 17 of the pole shoes 16 separated by an air gap 21 . The arrangement of the working magnets 18 with alternating opposite polarity is represented by the north poles N and the south poles S of the working magnets 18 .

The working magnets 18 are separated from their adjacent working magnets 18 by a gap 21 , the width of which is selected so that two adjacent working magnets 18 are at a distance d from one another, the width b of the grooves 12 in the region of the pole faces 16 of the pole shoes 15 corresponds.

The winding arrangement 13 has individual windings 22 , 23 , which are each wound in opposite directions around two adjacent pole shoes 15 . In this way, two adjacent pole shoes 15 , which are surrounded by a winding 22 or 23 , with their pole faces 16 form a common pole face, which, as shown in FIGS . 1 and 2, with the pole faces 17 of the working magnets 18 cover exactly can be aligned.

The second winding arrangement 14 has corresponding windings 24 , 25 , which are each arranged so that they overlap two adjacent windings 22 , 23 of the first winding arrangement 13 in half. As shown in Fig. 2 Darge, so engages the winding 22 of the first winding arrangement 13 , which is shown in solid lines, the pole pieces 15 'and 15 '', while the opposite winding coil 23 the pole pieces 15 ''' and 15th '''' Encompasses. The second winding arrangement 14 , which is shown in dashed lines, engages with its winding 24, the pole pieces 15 '' and 16 '''.

By loading the winding 13 forms on the pole shoes 15 ', 15 ''of the same name from the north pole and on the pole shoes 16 ', 16 '' of the same name, the south pole.

By applying the winding 14 , the magnetic pole forms between the poles of the same name, ie on the pole pieces 15 ', 16 ''the south pole and on the pole pieces 16 ', 15 '' the north pole, and thus a migration of the magnetic pole takes place a pole piece or half a pole instead.

By reversing the polarity on the winding 13 (as later on the winding 14 ), the magnetic pole formation is reversed, and thus the traveling magnetic field also forms a traveling rotating field, which the rotor then follows.

As shown in Fig. 1, the distance between the radial central axes of two adjacent grooves 15 in the circular angle 7.5 °, while the distance between the radial winding axes of the working magnets 18 on the outer rotor 20 is 15 ° in a circular angle. The distance in the circular angle between the radial central axes of two working magnets arranged with the same polarity is thus 30 °, which corresponds to a phase angle of 360 °.

The mutually associated windings 22 , 24 and 23 , 25 of the first and the second winding arrangement 13 and 14 are therefore at a distance which corresponds to a phase angle of 90 °.

The external rotor 20 is associated with a control solenoid 26 ring which rotates together with the outer rotor 20th The control magnetic ring 26 has the same number of permanent magnets, which serve as control magnets 27 and are arranged poliden table to the working magnet 18 on the outer rotor. Pulse generators 28 , 29 interact with the control magnets, which are expediently designed as Hall sensors and have a circular angular distance of 7.5 ° from one another, which corresponds to a phase angle of 90 °. Of the pulse generators 28 , 29 , the first 28 of the first winding arrangement 13 and the second 29 of the second winding arrangement 14 is assigned.

About terminals 13 ', 13 ''and 14 ', 14 '', the winding arrangements are connected to a supply circuit 30 , which is explained in more detail with reference to FIG. 3.

An internal rotor motor having a two-pole rotor is shown in a highly simplified manner as an electrical machine in FIG. 3. The winding arrangements 13 , 14 , which are also shown in a highly simplified manner, are to be thought of as being arranged fixed on a stator. The pulse generators 28 , 29 are shown arranged at a right angle to the winding arrangements 13 , 14 in accordance with the required phase shift of 90 °.

The supply circuit 30 has a first and a second inverter circuit 33 and 34 , which are constructed identically. Each inverter circuit has four controllable switching elements 35 , 36 , 37 , 38 , of which two 35 , 37 and 36 , 38 are connected to each other in series between the positive pole 39 of a DC voltage source and ground. As switching elements 35 , 36 , 37 , 38 z. B. power transistors or other suitable as a controllable switch serving electronic construction elements can be used. The control inputs 35 ', 36 ', 37 ', 38 ' of the switching elements 35 , 36 , 37 , 38 are acted upon by control electronics 32 which are supplied with the output signals of the pulse generators 28 , 29 .

In order to apply a two-phase, 90 ° phase-shifted three-phase current to the winding arrangements 13 , 14 , the output signals A 1 of the pulse generator 28 assigned to the first winding arrangement 13 are applied to a non-inverting and to an inverting switching element 40 or 41 . The output signal A 2 of the non-inverting switching element 40 is applied to the control input 35 'of the switching element 35 and to the control input 38 ' of the switching element 38 , while the output signal A 3 of the inverting switching element 41 to the control input 36 'of the switching element 36 and the control input 37 'of the switching element 37 is guided. In each case two switching elements lying in series with each other are controlled by control signals in opposite phases.

The output signal B 1 of the other pulse generator 29 is correspondingly via a non-inverting switching element 42 and an inverting switching element 41 to the control inputs 35 ', 36 ', 37 ', 38 ' of the switching elements 35 , 36 , 37 , 38 of the second inverter circuit 34 created.

The output signal A 1 of the pulse generator 28 , which supplies the pulses required for generating a square-wave AC voltage, is shown in FIG. 4. As long as the pulse generator 28 lies opposite the south pole S of the rotor 31 , the output signal A 1 = 0 and goes to 1 if, after a 180 ° rotation of the rotor 31, its north pole N lies opposite the pulse generator 28 . The output signal B 1 of the pulse generator 29 is generated in a corresponding manner, the pulse generator 29 providing an output signal 0 when it is acted upon by the north pole N of the rotor 31 , while it provides an output signal 1 when it is opposite its south pole S.

As long as the output signal A 1 1, the control inputs 35 'and 38 ' of the switching elements 35 , 38 are acted upon with a corresponding 1 signal, so that the switching elements 35 and 38 are conductive. At the same time, the other switching elements 36 , 37 are struck with a 0 signal and thus blocked. This results in a current flow through the inverter 33 and the connected to this first winding arrangement 13 , which is indicated by the arrows a.

If the output signal B 1 of the other pulse generator 29 is 0 at this point in time, the switching elements 35 , 38 of the other inverter 34 are acted upon by a 0 signal and thus blocked. About the inverting switching element 43 , a 1 signal is applied to the control inputs 36 ', 37 ' of the switching elements 36 , 37 , which thus become conductive. The resulting current flow through the inverter 34 and the second winding arrangement 14 connected to it is indicated by arrows b.

It can be seen that whenever the signal A 1 or B 1 assumes the value 0 or 1, a reversal of current occurs in the associated winding arrangements 13 or 14 , as does the current or voltage profiles A 4, B 4 show in Fig. 4. The voltages applied to the winding arrangements 13 and 14 and thus also the currents flowing through them thus have a 90 ° phase shift. In this way, a rotating magnetic field driving the rotor is generated.

It is particularly advantageous if the supply circuit 30 is constructed on a field effect basis and is only driven with voltages, that is to say it is operated without power. The switching elements 35 , 36 , 37 , 38 serving as circuit breakers are expediently designed as power transistors (power mosfet) which only require a control voltage and no control current, so that the losses for the control are in the milliwatt range.

Due to the special design of the pole faces 16 , 17 on the stator 10 or on the rotor 20 serving as the reaction part, the electrical machine according to the invention can be operated with a square-wave voltage as a motor, thereby making considerable savings in the area of the preferably electronic circuit and in the motor construction without affecting the concentricity and the efficiency of the motor. The electric machine can also be operated as a generator and then supplies a square-wave AC voltage to the inverter circuits 33 , 34 , which are then acted on in the opposite direction and work as a rectifier, so that at the connections to which a DC voltage is fed in during motor operation, in A DC voltage can be taken from generator operation. If desired and / or required, a rectangular AC voltage can also be taken from the terminals 13 ', 13 ''or 14 ', 14 '' of the winding arrangements 13 , 14 .

FIG. 5 shows a particularly preferred application example for the external rotor motor according to FIG. 1, in which it is used as a wheel-integrated drive for a motor scooter.

As shown in FIG. 5, an external rotor motor according to FIG. 1 is arranged in the radial inner region of a wheel rim 50 , the outer rotor 20 of which has an axially extending ring-shaped collar 51 which is fastened to an annular web 52 of the rim which extends radially inward. e.g. B. is welded. The rim 50 is fixed in a known manner with its ring web 52 to a wheel hub 53 , for. B. screwed on. The wheel hub is rotatably mounted on a wheel axle 54 in a known manner. The wheel is then held with the axle 54 in a known manner on the arms 55 of a wheel fork.

For the vehicle-fixed arrangement of the stator 10 , a holder 56 is provided which comprises a sleeve 57 placed on the axle 54 with a radial flange 58 , a carrier disk 59 attached to this, and an axially extending support ring 60 fastened radially on the outside to the carrier disk 59 , on which the stator 10 is placed. To stiffen the holder 56 , ribs 61 can be provided which additionally support the support plate 59 on the holding sleeve 57 .

The control magnet ring 26 , which rotates together with the outer rotor serving as a reaction part, is attached to the hub 53 in a suitable manner. The control solenoid 27 ring 62 is disposed axially opposite to which the pulsers 28, 29, one of which is shown, the control solenoid 27 mounted opposite a retaining ring.

The retaining ring 62 is attached to the carrier disk 59 in such a way that it can be adjusted in the circumferential direction at least over an area required for adjusting the pulse generators 28 , 29 relative to the pole faces of the stator.

Since the external rotor motor described is due to its large dimensioning due to slow speed and high Torques, he can in the manner shown directly into a drive wheel of a scooter inte be griert. There is no need for a gearbox Advantage that loss of power in the drive and noise generated by gearboxes can be avoided.

When driving, the engine speed and thus the driving speed proportional to the applied voltage. If the voltage is now reduced during driving, it drops  also the voltage-dependent nominal speed, which did that neuter engine speed, which depends on the driving speed is dependent, this nominal speed exceeds. Because the engine can also be operated as a generator to feed energy back to the drive voltage delivering vehicle battery, while holding a brake effect occurs. The braking effect by a lot to increase multiple times and at the same time almost braking to allow the vehicle to come to a standstill the stator windings in a manner not shown be short-circuited.

In addition to using the electric motor described in a scooter can also be used in a four-wheeler Electric vehicles with all-wheel drive are used, which makes considerable weight savings possible transmission and differential can be dispensed with.

Fig. 6 shows another embodiment of the electrical machine according to the invention as an internal rotor motor or generator, in which the ring-shaped carrier 19 , on which the working magnets 18 are arranged on the outside, is fastened in a rotationally fixed manner on a shaft 71 by means of carrier disks 72 . The stator 10 is attached to a housing 73 which surrounds the motor or generator and is rotatably mounted on the shaft 71 . A support ring 75 is provided on a radial wall 74 of the housing 73 , on which the pulse generators 28 , 29 , of which only one is shown, are held at a fixed angular distance from one another by means of a bracket 76 . The support ring 75 is angularly adjustable ver in the circumferential direction on the radial wall 74 of the housing 73, for example, by means of a screw 77 to allow adjustment of the pulse generator with respect to the pole faces on the stator 10 .

Claims (14)

1. Electrical machine with a stator which has a stator core separated by slots and two stator arranged on this winding arrangements with each having at least two windings, and with at least two permanent magnets to form pole faces with alternating polarity comprising reaction part, the pole faces of which Pole surfaces of the stator are arranged separately opposite one another by an air gap, characterized in that the pole surfaces ( 16 , 17 ) of the stator ( 10 ) and of the reaction part ( 20 ) can be aligned opposite one another over the entire area. 2. Electrical machine according to claim 1, characterized in that the pole faces ( 17 ) of the reaction part ( 20 ) in the direction of a relative movement between the stator ( 10 ) and the reaction part ( 20 ) have a distance (d) to each other, the width ( d) the grooves in the loading area of the pole faces ( 16 ) of the stator ( 10 ) corresponds. 3. Electrical machine according to claim 1 or 2, characterized in that the pole faces ( 16 ) of the stator ( 10 ) on pole shoes ( 15 ) are provided, which are formed by means of the grooves ( 12 ) on the stator core ( 11 ), and that each winding (22, 23) of the two winding assemblies (13, 14) each comprise two pole shoes (15) to accesses, so that the pole faces (16) of two of a winding (22, 23, 24, 25) embraced pole shoes (15) each form a common pole face, which can be aligned across the entire surface of the reaction part ( 17 ) on the reaction part ( 20 ). 4. Electrical machine according to claim 3, characterized in that in each case two adjacent windings ( 22 , 23 ; 24 , 25 ) of each of the two winding arrangements ( 13 ; 14 ) have an opposite winding sense and that in each case one winding ( 24 ) of the one Winding arrangement ( 14 ) overlaps two adjacent windings ( 22 , 23 ) of the other winding arrangement ( 13 ) in each case half. 5. Electrical machine according to one of the preceding claims, characterized in that the winding arrangements ( 13 , 14 ) via a supply circuit ( 30 ) with a square-wave voltage (A 4, B 4) can be opened, the two square-wave voltages (A 4th , B 4) are out of phase with each other by 90 °. 6. Electrical machine according to claim 5, characterized in that the supply circuit ( 30 ) is connected to a DC voltage source and has two pulse-controlled inverters ( 33 , 34 ), the outputs of which are each connected to a winding arrangement ( 13 , 14 ) and each are controlled by one of the relative movement between the stator ( 10 ) and reaction part ( 20 ) detecting pulse generators ( 28 , 29 ). 7. Electrical machine according to claim 6, characterized in that the two pulse generators ( 28 , 29 ) in Rich direction of the relative movement between the stator ( 10 ) and reaction part ( 20 ) have a distance from each other, which is half the distance between the corresponding edges of two Adjacent pole faces ( 17 ) on the reaction part ( 20 ) corresponds. 8. Electrical machine according to claim 6 or 7, characterized in that the pulse generator ( 28 , 29 ) relative to the stator ( 10 ) stationary in the direction of the relative movement between the stator ( 10 ) and the reaction part ( 20 ), but are arranged together adjustable. 9. Electrical machine according to one of claims 6 to 8, characterized in that the pulse generators ( 28 , 29 ) are each arranged with respect to the associated Wicklungsan arrangement ( 13 , 14 ) so that their position with respect to the direction of movement speaks the area ent , in which two adjacent coils ( 22 , 23 ; 24 , 25 ) of the associated winding arrangement ( 13 ; 14 ) adjoin each other. 10. Electrical machine according to one of claims 6 to 9, characterized in that Hall sensors are provided as pulse generators ( 28 , 29 ) which cooperate with permanent magnets ( 18 , 27 ) arranged on the reaction part ( 20 ). 11. Electrical machine according to claim 10, characterized in that on the reaction part ( 20 ) control magnets ( 27 ) are provided, which are arranged with respect to polarity and position accordingly the pole faces ( 17 ) forming permanent magnets ( 18 ). 12. Electrical machine according to one of the preceding claims, characterized in that the winding arrangements ( 13 , 14 ) are each short-circuitable. 13. Use of an electrical machine according to one of the preceding claims as a drive motor for a motor vehicle, wherein the stator ( 10 ) and the reaction part serving as a rotor ( 20 ) are arranged integrated on a vehicle wheel to be driven. 14. Use according to claim 13, wherein the reaction part as an annular outer rotor ( 20 ) with preferably twenty-four pole faces ( 17 ) is attached to the wheel, in particular to the wheel rim ( 50 ), and wherein the stator ( 10 ) is arranged fixed to the vehicle.