EP1618646A1

EP1618646A1 - Multiphase multipole high speed linear or rotational synchronous motor

Info

Publication number: EP1618646A1
Application number: EP04763714A
Authority: EP
Inventors: Wolfgang Heinrich; Dieter Gramann; Thomas Lapp
Original assignee: INA Drives and Mechatronics GmbH and Co KG
Current assignee: Schaeffler Industrial Drives AG and Co KG
Priority date: 2003-08-05
Filing date: 2004-08-02
Publication date: 2006-01-25
Also published as: DE10335792A1; WO2005018073A1

Abstract

The invention relates to a multiphase, multipole, high speed, linear, or rotating synchronous motor with a primary piece, comprising a preferably laminated yoke with a number of teeth with teeth crowns and slots, located between the same, with pole or armature windings, or corresponding winding packets located in the slots, a secondary piece, embodied essentially opposite the primary piece and a number of permanent magnets of alternating polarity arranged on a common return plate. The slot outlets have an essentially uniform slot distribution Tn and the permanent magnet poles have an essentially uniform pole distribution Tp and several windings running in adjacent grooves are connected to the same supply. According to the invention, several windings running in adjacent slots are connected with the same electrical motor phase and flow and the windings corresponding to the same motor phase are connected in series. Also, the winding direction and the flow direction alternate from slot to slot. Each winding is embodied as a tooth winding enclosing a tooth and has n windings. The ratio between slot distribution Tn and pole distribution Tp is selected to be approximately 1 and the same arrangement of teeth and permanent magnets is first repeated over a number of teeth.

Description

Multi-phase, multi-pole, high-speed linear or rotary synchronous motor Description

The invention relates to a multi-phase, multi-pole, high-speed linear or rotary synchronous motor with a primary part, comprising a preferably laminated yoke with a plurality of teeth with tooth heads and grooves located between them, and pole or armature windings arranged in the grooves, a secondary part, which is essentially the primary part is formed opposite and has a plurality of permanent magnets of alternating polarity, which are arranged on a common reflux base, furthermore the groove outputs have an essentially uniform groove pitch T _n and the permanent magnet poles have an essentially uniform pole pitch T _p , and several lying in side by side Slot-running windings are connected with the same current, according to the preamble of claim 1.

Electric synchronous motors consist of a so-called primary part, which contains the actual winding, and a reaction part equipped with permanent magnets, also called a secondary part. A distinction is made in such motors between tinned or iron-containing or ironless motors.

In all synchronous motors of the type described above, which have a clearly recognizable tooth structure in the primary part and pronounced magnetic poles in the secondary part, changes in the magnetic resistance occur when there is relative movement between the two parts, i.e. Reluctance differences, which lead to undesired locking effects or so-called reluctance forces.

Such an effect is disruptive when using synchronous motors, since it mainly affects the synchronous properties and cannot be eliminated or can only be eliminated with great effort by means of control measures. It is also known that the reluctance effect mentioned above depends very much on the basic arrangement of the pole structure in the primary and secondary part.

Such a pole structure of the prior art is shown in Fig. La. This figure also discloses a conventional arrangement with regard to the division ratio between the slot pitch T _n and the pole pitch T _p .

The primary part is provided with the reference number 1 and the secondary part with the reference number 2. The primary part 1 has a number of teeth 4 which are connected via a yoke 5. There are grooves 3 between the teeth 4 which receive the winding.

In order to keep reluctance ripples low, it is previously known to minimize the width 3a of the groove exit, which is realized by a mushroom-shaped design 4a at the free end of the teeth. Such a mushroom head structure is known for example from DE 197 01 342 AI, DE 33 20 805 C2, but also from CZ 288 081 B.

Such a mushroom head design of the teeth has a major disadvantage in terms of production technology, since it is not possible to insert prefabricated windings through the remaining narrow grooves past the tooth tips 4a into the usable space.

The pole arrangement indicated in FIG. 1 a is characterized by a groove pitch T _n which differs clearly from the magnetic pole pitch T _p . The ratio T _n / T _p here is 1/3 = 0.33. As mentioned above, there is a detent effect when the primary and secondary parts are displaced relative to each other due to the reluctance differences. Such an undesirable locking effect is demonstrably greater the further apart T _n and T _p are, and, as also explained, is disruptive with regard to the desired synchronous properties of the engine.

FIG. 1b shows a possible basic winding diagram for the basic motor arrangement according to FIG. The support winding is according to the known prior art with a number of turns W by one Group of teeth 4 laid in the grooves 3. Only the part of the winding that is routed or located in the slots itself contributes to the force generation of the motor.

The portion 9 of the winding, also called winding end, located outside the slots merely increases the winding resistance and thus the loss portion, i.e. there is a decrease in the efficiency of the engine.

The pole pitch ratio T _n / T _p according to FIG. 1 a and the electrical phase position specified thereby determine which phase assignment and which winding sense the winding strands laid in the slots must have. This shows a relationship between the selected pole pitch ratio and the possible winding variants that depend on it.

Synchronous motors develop an increasing electrical counter voltage with increasing relative speed between stator or primary part and rotor, ie the secondary part. This counter voltage results in U _g = k _v • v or U _g = k _ω . ω. If the counter voltage reaches the range of the operating voltage or the intermediate circuit voltage for converters, the current flow into the motor is limited and no further speed increase is possible.

Particularly in the case when the motor is to generate a high force or a high torque and a high speed or a high speed at the same time, the voltage constant k _v (k _ω ) is very large due to the necessary high number of poles and the corresponding motor is required then a very high operating voltage in order to achieve the desired high speeds.

Motors with a high power or torque yield are also designed in a known manner with large numbers of poles, the problem of increasing counter voltages, which must be suppressed, now arise. Since the intermediate circuit voltages of common inverters are usually limited to values between 300 and 600 V, high speeds can only be achieved by reducing the k _v (k _ω ) constant, except when using so-called field weakening operation.

The consequence of this is that very low-resistance and low-inductance windings with correspondingly low voltage constants and the associated low force constants can be realized. As a result, however, the current requirement I = F / k _f (I = M / Km) for generating the desired forces F or torques M increases due to the speed requirements, which in turn means that the windings must either be designed with very large cross sections or else the arrangement of several in-phase partial windings is to be provided, which are to be connected in parallel.

However, the method explained above for realizing low winding resistances has decisive disadvantages.

A parallel connection of partial windings has the disadvantage that the smallest differences in the counter voltages generated in the partial windings lead to unwanted equalizing currents and, from a certain speed, to thermal and damping effects which can no longer be controlled.

A further increase in the winding cross-section in conventional motor structures with enamelled wire windings in the slots is either limited due to the manageable wire cross-sections or, in the case of usual pole pitch ratios between the primary and secondary part, involves a considerable amount of wiring outside the slots.

Ultimately, with conventional wire windings with large winding cross sections, eddy current effects lead to undesirable heat losses. All pole pitch and winding constellations known to date from the prior art do not meet the given requirements for a low speed constant with a high power yield with a minimized electrical resistance with minimal reluctance ripples in the desired manner.

With regard to the prior art, reference is also made to DE 92 958, which describes a multi-phase machine with an unequal number of armature coils and poles. According to the solution there, a specific pole pitch ratio is proposed for more efficient winding design and a series connection of windings combined in pole groups is also disclosed.

However, the solution there does not relate to a synchronous machine with permanent magnets and does not provide any information on the counter-voltage problem explained above or on reluctance ripple suppression.

The teaching according to DE 33 20 805 C2 aims at improving the efficiency and minimizing the reluctance ripple of a synchronous motor, where the motor is divided into zones and separate windings are connected in series. A small phase offset from winding to winding up to the phase angle between two phases is also addressed there.

The German patent DE 195 03 610 C2 goes in a similar direction with the aim of improving the efficiency of an engine and improved manufacturing technology. A winding conductor is arranged within a defined zone with an alternating direction around successive stator poles. Furthermore, a meandering winding is shown there, although the pole windings are connected in series. In the solution there, the slot width basically corresponds to the width of the winding conductor, and sections of the winding conductor which meet within a pole slot are arranged one above the other. In the spindle motor with minimized torque cross nipples according to US Pat. No. 4,874,712, a fixed pole pitch with nine tooth poles and eight magnetic poles is used, the pole windings being connected in series. There is no phase shift between the teeth. In the tooth windings there, only every second one is connected in series, with the

Assignment to the three phases does not correspond to the logical phase offset of the poles. The counter voltage problem is not addressed in the cited US patent.

From the above, it is therefore an object of the invention to provide a further developed, multi-phase, multi-pole, high-speed linear or rotary synchronous motor with primary and secondary part, the motor should have an efficient and low-resistance winding for operation even at the highest speeds and which is particularly low in reluctance ripples ,

The object of the invention is achieved with an object according to the teaching of claim 1, the subclaims representing at least expedient refinements and developments.

According to the invention, the proposed motor construction is therefore based on a plurality of windings which run in adjacent grooves and which are connected to the same electrical motor phase and current supply. The windings belonging to the same motor phase are connected in series, with the winding direction and the current direction changing from slot to slot.

Each winding is designed as a tooth winding comprising a tooth and has n turns. Such a tooth winding is the most efficient and technologically very easy to carry out.

The series connection of the tooth windings is cheaper than known parallel connections, ie the side effects given in the prior art, which impair the efficiency of the motor, do not occur. The path between the tooth windings or from slot to slot is chosen to be as short as possible.

In order to keep the winding strands outside of the slots as short as possible, the winding strands and toothed windings belonging to one phase lie closely together.

The aim is also to minimize the amount of wiring between the winding strands connected in series.

The pole division ratio T _n / T _p according to the invention at least over sections of the motor close to 1, ie also close to larger or close to 1, ensures that within a wide range over several teeth from slot to adjacent slot with regard to the direction of the desired current and thus there is a constant change in the winding direction. Directly adjacent winding strands, which form the tooth windings, can thus be electrically connected in series in the desired manner.

In itself, a noticeable reluctance ripple wave is caused by each groove over a magnetic period. Due to the proposed pole pitch ratio T _n / T _p close to 1, the ripple waves caused by the individual slots overlap in such a way that mutual, extensive compensation or cancellation takes place. This drastically reduces the number of reluctance ripples that result.

The plurality of teeth mentioned on the claims is at least six, the low electrical phase offset being set to values <60 °.

The winding is advantageously designed as a continuous, electrically insulated, high-temperature-resistant strand, which can be stuffable in relation to the insertion into the groove, and has a large cross section for carrying a high desired current. The winding itself has only a few tooth turns and is accordingly in the slots laid. This measure results in the desired reduction in the wiring effort and there is a minimization of the winding resistance of the overall motor, with the result of the desired increase in efficiency.

The use of an electrically insulated strand minimizes undesirable skin or other eddy current effects with the usual high-frequency control, with the advantages that this gives compared to a winding consisting of a copper wire with a large cross section. The strand here consists of at least 20, preferably 60 to 100 individual cores, i.e. there is high core.

In an advantageous embodiment of the invention, the tooth tips are specially designed. Here, the tooth heads are able to accommodate shaped bodies or shaped pieces with the aim of making the winding strand, also prefabricated, in grooves in a technologically simple manner, i.e. to bring the interdental spaces.

For this purpose, the respective tooth tip ends have a recess or a recess. These recesses or recesses serve to fix the aforementioned shaped bodies or shaped pieces, which are oriented in such a way that the width of the groove exit is reduced.

After the winding has been introduced or arranged in the slots, the shaped bodies or shaped pieces are connected to the free tooth tip ends in a material-locking and / or positive-locking or non-positive manner.

The shaped pieces or shaped bodies preferably consist of a soft magnetic material which, in a special embodiment, is different from the tooth material, i.e. the laminated core of the primary part is electrically insulated.

The shaped bodies or shaped pieces are preferably glued to the respective recess or recess. After the Introducing the winding and fixing the shaped bodies or shaped pieces results in an overall potting of the partial arrangement.

The insulation between the shaped body or shaped piece and the tooth material can preferably be formed by an adhesive layer which also serves to fasten the respective shaped body in the corresponding recess.

In one embodiment of the invention, the recesses or recesses are formed on both sides of a respective tooth tip end and have a groove shape. This groove can have a semicircular, rectangular, square, triangular or trapezoidal cross section.

As an alternative or in addition, recesses or recesses can be located on the end face of the tooth head, the respective molded body or the shaped piece, widening the tooth head, being placed and locked.

The invention will be explained in more detail below using an exemplary embodiment and with the aid of figures.

Here show:

2a shows a section of a linear motor or a development of a rotary motor with primary part and secondary part;

2b shows a winding diagram with information on the electrical phase shift in a motor according to the exemplary embodiment;

Fig. 3 is a schematic diagram of a rotary synchronous motor with seven pole pairs or fourteen permanent magnet poles and

Fig. 4 shows a motor analogous to the illustration of Fig. 3, but with a winding meandering through the grooves. With regard to FIG. 2a, reference is made to the explanations of the basic construction of a synchronous motor in the introduction to the description, the same reference numerals being used for the same parts. B _n defines the width of the slot exits, with shaped pieces being provided for widening the tooth tips 4 a, which are located in recesses or recesses of the respective tooth tip or are introduced there.

This widening of the tooth heads for the purpose of reducing the width B _n is advantageous, taking into account the avoidance of annoying reluctance ripples.

The proposed construction ensures that depending on the total number of poles 6 of the secondary part 2 or the total number of teeth 4 of the primary part 1, which should be divisible by the number of phases, the pole pitch ratio T _n / T _p is set such that the same tooth-magnet constellation is repeated only over the largest possible number of teeth 4 and thus magnetic periods 2 T _p .

According to FIG. 2a, these are nine teeth with a ratio T _n / T _p = 0.88. There is therefore a phase shift of 40 ° with respect to the partial EMF or slot-related counter voltages generated in the adjacent slot windings 8, which allows them to be electrically connected in series over a total of 120 °, so that they operate on the same motor phase and the same target current suspend. In motors according to the known prior art, this is not possible because there the phase assignment changes over several grooves. Either there is overlap or there is a constant change of phase assignment in the case of so-called tooth windings.

In the case of larger motors with a higher number of poles, significantly more teeth can be combined into such pole groups within one motor phase. With a ratio T _n / T _p going towards 1, a much better effect can be achieved with a view to the desired reluctance ripple suppression. Each phase winding U, V, W is a series connection of successively immediately adjacent tooth windings with n turns, the winding direction of the winding strands 8 changing from slot to slot.

2b shows the winding diagram and the electrical phase offset, based on the electromotive forces generated over the respective slot length when the motor is operating as a generator.

Since the target current of a synchronous motor in each motor phase is in phase with the corresponding phase-related EMF, the resulting force of the entire motor is made up of the respective phase-shifted partial forces of the slot windings connected in one phase and the superimposition of the phase forces in a multi-phase system in a known manner.

In a particularly advantageous embodiment of the invention, a long and continuous, electrically insulated, high-wire strand with a large cross section corresponding to the target current is laid in the respective grooves with only a few tooth turns.

With this measure, the wiring effort can be reduced and the winding resistance of the entire motor is reduced, with the result of an increase in efficiency.

A primary part or a primary part cutout with six teeth and six slots, in which three adjacent tooth windings are assigned to three different motor phases and the number of magnets is five, is to be regarded as the limit case and the smallest motor element that can be realized.

The EMF-related electrical phase shift from groove to groove is 60 ° in such a variant. In the case of closed or rotary motors, at least two such motor segments must then be distributed over the circumference and electrically connected in opposite directions. Ideally, according to the basic idea of the invention, the total number of teeth of a primary part is divided into an equal number of groove-tooth groups corresponding to the number of phases and provided with a low EMF-related electrical phase offset of a few degrees. This electrical phase offset is 360 ° / number of slots.

With a correspondingly large motor diameter, it is thus possible, for example with 44 magnetic poles 6 and 45 slots 3, to divide the total useful number into three slot-tooth groups, each with five slot windings connected in series, which are assigned to the motor phases U, V, W. The pole pitch ratio T _n / T _p is then very favorably 0.977.

3, a rotary synchronous motor with seven pole pairs or fourteen permanent magnet poles 6 is assumed. The number of grooves and teeth there is fifteen. This results in a pole pitch ratio T _n / T _p of 0.933.

It can be seen that the same relative position of the primary and secondary part is repeated only after every fifteenth tooth. As a result, the reluctance differences during the movement are largely eliminated and reduced to a practically irrelevant level. The schematic winding represents only one possible variant with regard to the number of turns around each tooth.

The EMF-related phase offset between two adjacent winding strands according to FIG. 3 is 24 °. Of the fifteen teeth or grooves, five are combined in a groove-tooth group, which in turn are each assigned to the three phases U, V, W.

Each phase winding consists of a single, continuous strand, which is laid around each of the five teeth with 3.5 tooth turns through the slots. There is a winding strand with seven wires in each slot. In this constellation, the tooth windings are laid from slot to slot in the shortest possible way. The use of a strand with a large cable cross-section in the range of 2.5 to 6 mm ² results in a very low winding resistance with a correspondingly low voltage constant. The three phase windings are connected and connected in a known manner in an electrical three-phase system.

The illustration according to FIG. 4 shows a similar motor as described above, with meandering windings being assumed there. This example is an extreme case for a winding with minimized counter voltage with a defined number of poles.

It should be pointed out that it is irrelevant for the use of the teaching according to the invention whether it is a closed, rotary or finite linear motor. The relative forces and speeds attributable to a motor element defined in this way can be converted in a known manner over the given radius.

LIST OF REFERENCE NUMBERS

1 primary part 2 secondary part

3 grooves

3a groove with a width B _n

4 teeth

4a tooth heads / fittings 5 yokes

6 permanent magnets

7 common reflux sole

8 winding T _p pole pitch T _n slot pitch ω angular frequency rotary v velocity linear

M torque

F force R radius related to the force application point Af force constant

Km torque constant

Ku counter voltage constant

I motor current

Claims

claims

1. Multi-phase, multi-pole, high-speed linear or rotary synchronous motor with a primary part, comprising a preferably laminated yoke with a plurality of teeth with tooth tips and grooves located between them, as well as pole or armature windings arranged in the grooves, a secondary part, which is essentially the primary part is formed opposite and has a plurality of permanent magnets of alternating polarity, which are arranged on a common reflux sole, wherein the

Slot outputs have an essentially even slot pitch (T _n ) and the permanent magnet heads have an essentially even slot pitch (T _p ) and several windings running in adjacent slots are connected with the same current, characterized in that several windings running in adjacent slots wired with the same electrical motor phase and current supply and the windings belonging to the same motor phase are connected in series, the winding direction and the current direction change from slot to slot, each winding is designed as a toothed winding and has n turns, the ratio between slot pitch (T _n ) and pole pitch (T _p ) is selected at least over sections of the motor close to 1 and the respective identical assignment of tooth and permanent magnet is repeated only over a large number of teeth and between two adjacent grooves with respect to the over Slot length in the respective winding generated EMF with respect to the magnet period 2 T _{p there is} a small electrical phase offset.

2. Motor according to claim 1, characterized in that the plurality of teeth has the value> 6.

3. Motor according to claim 1 or 2, characterized in that the phase offset is <60 °.

4. Motor according to one of the preceding claims, characterized in that a continuous winding with the same motor phase and current supply is provided in at least three adjacent grooves.

5. Motor according to one of the preceding claims, characterized in that each phase associated strands of the winding consists of a single, externally insulated, high-temperature-resistant, multi-core strand with a large cross-section and this is laid through all the slots associated with the respective phase with a small number of turns ,

6. Motor according to claim 5, characterized in that the strand is arranged in a meandering shape around the teeth in the grooves.

7. Motor according to one of the preceding claims, characterized in that the tooth heads comprise shaped bodies or shaped pieces which, after introducing or arranging the winding in the slots with the free

Tooth end ends are integrally and / or positively connected, for which purpose the respective tooth head ends have at least one recess or recess.

8. Motor according to claim 7, characterized in that the moldings or moldings consist of a soft magnetic material.

9. Motor according to claim 7 or 8, characterized in that the moldings or moldings are electrically insulated from the tooth material.

10. Motor according to one of claims 7 to 9, characterized in that the shaped bodies or shaped pieces are glued to the respective recess or the respective recess.

11. Motor according to claim 10, characterized in that the insulation between the molded body or molding and the tooth material is formed by the adhesive layer.

12. Motor according to one of claims 7 to 11, characterized in that the recesses or recesses are formed on both sides of a respective tooth tip end and have a groove shape.

13. Motor according to claim 12, characterized in that the groove shape has a semicircular, rectangular, square, triangular or trapezoidal cross section.

14. Motor according to one of claims 7 to 11, characterized in that the recesses or recesses are located on the end face of the tooth tips, the respective molded body or the respective shaped piece being placed widening the tooth tip.

15. Motor according to one of claims 7 to 14, characterized in that the shaped pieces or shaped bodies reduce the magnetically effective width of the groove outlet.