Individual control of sub-conductors of a dynamoelectric machine stator equipped with conductor bars

Abstract

The invention relates to a drive (20) comprising a rotary dynamoelectric machine (1) having a stator (2) and a rotor (3), the stator (2) having a winding system in a magnetically conductive body, in particular a laminated core (11), the stator (2) and the rotor (3) being separated from one another by an air gap (23), the winding system being positioned in grooves (18) of the magnetically conductive body which face the air gap (23), the winding system having one conductor bar (8) per groove (18), which conductor bar is subdivided into sub-conductors (14, 15) or sub-conductor bundles, the sub-conductors (14, 15) or sub-conductor bundles of which are electrically contacted at a first end of the conductor bar (8) with at least one inverter module (6), and the sub-conductors (14, 15) or sub-conductor bundles of which are combined at the other end, i.e. the second end of the conductor bar (8) at the other end face of the magnetically conductive body of the stator (2), with the other sub-conductors (14, 15) or sub-conductor bundles of the other conductor bars (8) positioned in the grooves (18) to form a short-circuit ring (9).

Description

[0001] Description

[0002] Individual control of partial conductors of a stator of a dynamoelectric machine provided with conductor bars

[0003] The invention relates to a drive with a dynamoelectric machine with inverter modules, a method for producing a stator of a dynamoelectric machine with inverter modules, as well as the use of such a drive.

[0004] Winding systems of stators of dynamoelectric machines are constructed from winding wires or conductor bars that are arranged in slots of a magnetically conductive body of the stator.

[0005] However, if the winding system does not consist of a distributed three-phase winding using cables or wires, but of a number of conductor bars, a high current is required due to the comparatively low inductance. This high current requires only a relatively low voltage (C 100V) due to the low ohmic resistance of the conductor bars. This low voltage makes it possible to arrange the inverter modules, which control the conductor bars, at a relatively short distance from one another on the dynamoelectric machine.

[0006] These conductor bars are connected to one another on one end face of the magnetically conductive body of the stator via a short-circuit ring, and are fed on the other end face of the magnetically conductive body of the stator by respectively assigned inverter modules, as is known, for example, from DE 10 2005 032 965 A1.

[0007] These low voltages resulting from the winding concept enable a compact design of the entire drive, i.e. the dynamoelectric machine with the power electronics.

[0008] Instead of the complex, labor-intensive distributed stator winding, a cost-effective, robust bar winding is used. Each individual stator slot is equipped with a bar depending on the operating conditions. Each bar is currently connected to its own power electronics for the power supply and control, the inverter module. The number of phases in the machine is therefore identical to the number of slots in the stator. The magnetic field required to operate the machine is generated by high currents (up to several thousand A) in the stator bars at low voltages. In the previous design, the high bar currents were in turn generated by connecting semiconductor components (Si components) in parallel, which places very high demands on the hardware structure and the firing pulse control of the components in the inverter modules.

[0009] The control software is subject to high demands for the simultaneous generation and transmission of the ignition pulses to the power converters.

[0010] However, if switching at such high currents is delayed in only a few components, this leads to thermal destruction of the circuit board structure of the respective inverter module.

[0011] When designing the hardware, the uniform cooling of the components, the uniform current flow and the low-resistance connection design for the (high) current transfer from the circuit board to the stator bar are crucial.

[0012] Proceeding from this, the invention is based on the object of providing a drive with a dynamoelectric machine, the stator of which has conductor bars and a short-circuit ring, and which avoids the above-mentioned disadvantages. The solution to the stated object is achieved by a drive with a rotary dynamoelectric machine with a stator and a rotor, wherein the stator has a winding system in a magnetically conductive body, in particular a laminated core, wherein the stator and rotor are separated from one another by an air gap, wherein the winding system is arranged in slots of the magnetically conductive body which point towards the air gap, wherein the winding system has a conductor bar divided into partial conductors or partial conductor bundles per slot,whose partial conductors or partial conductor bundles are electrically contacted at a first end of the conductor bar with at least one inverter module and whose partial conductors or partial conductor bundles at the other end, i.e. second end of the conductor bar on the other end face of the magnetically conductive body of the stator, are combined with the other partial conductors or partial conductor bundles of the other conductor bars arranged in the respective slots to form a short-circuit ring.

[0013] The solution to the problem is also achieved by a method for producing a stator of a rotary dynamoelectric machine, which has a winding system in a magnetically conductive body, in particular a laminated core, by the following steps:

[0014] - manufacturing the magnetically conductive hollow cylindrical body, in particular the laminated core of the stator, with grooves facing the inner surface of the hollow cylindrical body,

[0015] - Contacting of connecting elements to a first axial end of each conductor bar of a groove, wherein the conductor bar is constructed from partial conductors which are provided with the connecting elements individually and / or as partial conductor bundles and which run parallel or interlaced at least within the groove,

[0016] - axial insertion of the partial conductors or partial conductor bundles of the respective conductor bars provided with the connection elements into the respective grooves of the magnetically conductive body or laminated core, - contacting at least one short-circuit ring at the second ends of the conductor bars and positioning and contacting the inverter modules to the partial conductors or partial conductor bundles of the conductor bars provided with the connection elements.

[0017] The solution to the problem set is also achieved according to the invention by a drive in the industrial environment, in particular in compressors, compressors or pumps, whose dynamoelectric machine has a stator according to the invention.

[0018] According to the invention, the complex, labor-intensive distributed winding system in a stator of a dynamoelectric machine of a drive according to the invention is formed by a cost-effective, robust winding system made up of conductor bars. Each individual slot of the stator is provided with a conductor bar made up of partial conductors. Each partial conductor or partial conductor bundle of a conductor bar is connected to its own power electronics for the power supply and control, i.e. to its own inverter module. The magnetic field required for the operation of the dynamoelectric machine is generated by comparatively high currents in the conductor bars at simultaneously low voltages (for example < 100V). The current of a conductor bar is distributed accordingly between the partial conductors or partial conductor bundles of this conductor bar in a controlled manner that can be predetermined.

[0019] A partial conductor is understood to mean the division of a rod-shaped conductor into several, particularly parallel, partial conductors.

[0020] The conductors are bare or insulated from each other.

[0021] The conductor elements can have different cross-sections, such as rectangular or round. In any case, a high packing density of the conductor elements in the slot is desirable. Skin and proximity effects can be reduced by twisting the conductor elements in the slot.

[0022] The inventive approach of the drive now consists in no longer generating the high bar current by connecting many power converters or inverter modules in parallel, but rather each individual power converter element or inverter module is assigned a partial conductor or a partial conductor bundle (i.e. two, three, four or more individual partial conductors connected in parallel) of the conductor bar.

[0023] An inverter module is understood to be a power semiconductor arrangement which is connected on the input side to a direct voltage source and on the alternating current side to a partial conductor or partial conductor bundle of a conductor bar, whereby a control of this inverter module or a control superimposed on the inverter modules controls the respective power semiconductors accordingly.

[0024] The parallel connection of the total current per slot is thus achieved by the cross-sectional division of the individual conductor bar and the desired high bar current per slot of the stator is generated by the sum of the partial conductor currents in this slot.

[0025] Shifting the parallel connection of the currents from the semiconductor level of an inverter module to the individual level of a conductor bar results in a number of advantages:

[0026] - It is no longer necessary for the current to be carried uniformly on the circuit boards of the inverter module to the central connection point for the current transfer to the conductor bar. In other words: according to the invention, the current is now transferred directly from the inverter module to the bar sub-conductor or bar sub-conductor bundle. - This means that, for example, no 600 A (or even higher currents) need to be transferred at low resistance from the circuit board of the inverter module to the conductor bar using special, particularly low-resistance connection techniques such as butt welding, but only, for example, 10 x 60 A. This considerably simplifies the contacting of the inverter module to the sub-conductor or sub-conductor bundle via their respective connection elements, as these can be designed as plug connections, for example.

[0027] The use of plug connectors as connection elements makes it easier to replace the hardware, e.g. the inverter module, during servicing.

[0028] According to the invention, a significantly higher redundancy of the drive results, since it is no longer possible for an entire conductor bar and thus the affected inverter module to fail, but at most parts of it or partial conductors or partial conductor bundles or their associated inverter modules.

[0029] A delayed transmission of firing pulses therefore does not result in the current-carrying capacity of other power semiconductors in the inverter module being exceeded and is therefore less critical. Only a very brief current asymmetry may occur within the conductor bar of a slot, and the associated field asymmetry with respect to conductor bars in neighboring slots with the same current drive. However, this does not restrict the proper operation of the drive.

[0030] By shifting the parallel connection of the currents from the semiconductor level of an inverter module to the individual conductor bar level, the control software for generating the ignition pulses of the power semiconductors of an inverter module is subject to less time-critical requirements. The invention also simplifies the cooling of the power components of an inverter module, since each inverter module can be considered individually and is no longer connected via a common current guide.

[0031] Due to operating frequencies of 50 Hz and higher, the conductor bar is generally no longer made of solid material to reduce eddy current losses, but is constructed according to the invention from bare or mutually insulated partial conductors, which can be made of solid or hollow material.

[0032] Furthermore, the conductor elements of a conductor bar can pass through any geometric position in the slot when viewed axially along the slot.

[0033] In particular, the conductor elements of a conductor bar are Roebeled. During Roebeling, the position of each conductor element over the axial length of the slot is guided in such a way that current displacement can be avoided. Viewed along the axial path, each section of the conductor element of the Roebeled conductor now has, on average, the same vertical position in the slot over the length of the slot, so that the current density in all twisted parallel conductor elements is approximately constant and current displacement is avoided. An increase in resistance caused by current displacement, which would inevitably be associated with increased ohmic losses, can thus be greatly reduced.

[0034] According to the invention, due to the decoupling of the partial conductors of a conductor bar, conductor bars or their partial conductors can also be used without Verroebeling.

[0035] According to the invention, instead of the overall cross-section, these individual conductors or conductor bundles of a conductor bar are combined – depending on the current-carrying capacity of the converter on the circuit board – and connected to the semiconductor components. For example, in the original design, 40 conductors of a bar were combined and 600 A was applied to the conductor bar using 10 parallel converter elements of 60 A each. Now, four conductors are connected to each of the ten 60 A converters. The total current for the conductor bar in the slot is again 600 A.

[0036] The power converter or inverter modules and the software for operating the hardware components can no longer be viewed in isolation. The machine and power converter are directly connected and should be viewed as an integral functional unit.

[0037] According to the invention, the high bar current is no longer generated by connecting many components in parallel, but rather each converter component is assigned a partial conductor or partial conductor bundle of the bar. The parallel connection is thus achieved by dividing the cross-section of one conductor bar per slot of the stator, and the high bar current in a slot is now generated by the sum of the partial conductor currents in this slot, without being exposed to an increased probability of failure of the inverter module.

[0038] The invention and further advantageous embodiments of the invention are explained in more detail using exemplary embodiments shown in principle, in which:

[0039] FIG 1 perspective sectional view of a drive,

[0040] FIG 2 Longitudinal section of a drive,

[0041] FIG 3 Detailed view of a conductor bar on a

[0042] front side of the stator,

[0043] FIGS 4 to 9 show various representations of different conductor sections of a conductor bar,

[0044] FIG 10, 11 Longitudinal section of a basic arrangement of inverter modules on partial conductors of a conductor bar, FIG 12, 13 Top view of a basic arrangement of inverter modules on partial conductors of a conductor bar.

[0045] It should be noted that terms such as "axial," "radial," "tangential," etc., refer to the axis 5 used in the respective figure or in the respective example described. In other words, the directions axial, radial, and tangential always refer to an axis 5 of the rotor 3 and thus to the corresponding axis of symmetry of the stator 2. "Axial" describes a direction parallel to axis 5, "radial" describes a direction orthogonal to axis 5, toward it, or away from it, and "tangential" is a direction that is at a constant radial distance from axis 5 and, at a constant axial position, circular around axis 5. The term "in the circumferential direction" is synonymous with "tangential."

[0046] With reference to a surface, e.g. a cross-sectional area, the terms "axial", "radial", "tangential" etc. describe the orientation of the normal vector of the surface, i.e. the vector that is perpendicular to the surface in question.

[0047] The term "coaxial components," e.g., coaxial components such as rotor 3 and stator 2, refers to components that have the same normal vectors, i.e., for which the planes defined by the coaxial components are parallel to each other. Furthermore, the term should imply that the centers of coaxial components lie on the same rotation or symmetry axis. However, these centers may be located at different axial positions on this axis, and the planes mentioned may therefore have a distance >0 from each other. The term does not necessarily require that coaxial components have the same radius.

[0048] The term "complementary" in the context of two components which are "complementary" to one another means that their external shapes are designed in such a way that one component can preferably be arranged completely within its complementary component, so that the inner surface of one component and the outer surface of the other component ideally touch each other seamlessly or over their entire area. Consequently, in the case of two objects which are complementary to one another, the external shape of one object is determined by the external shape of the other object. The term "complementary" could be replaced by the term "inverse".

[0049] For the sake of clarity, in some cases where components are present more than once, not all of the components shown are provided with reference symbols in the figures.

[0050] The described embodiments can be combined in any way. Individual features of the respective embodiments can also be combined without departing from the essence of the invention.

[0051] 1 shows a perspective sectional view of a drive 20 with a dynamoelectric machine 1 and inverter modules 6 arranged directly on its end face. The dynamoelectric machine 1 has a laminated core 11 of a stator 2, in which a winding system 7 is arranged in slots pointing towards an air gap 23. This winding system 7 of the stator 2 is made up of conductor bars 8, which are composed of partial conductors 14, 15 and which are contacted on one end face of the stator 2 via connection elements 17 with inverter modules 6 of a conductor bar 8, which are respectively assigned to the partial conductors 14, 15 or partial conductor bundles. On the other end face of the stator 2, these conductor bars 8, which are composed of partial conductors 14, 15 or Partial conductor bundles are electrically combined to form a short-circuit ring 9 of the stator 2. On this other end face there is also a cover 13, which may be...can also be designed as a bearing shield.

[0052] Coaxially arranged at a distance from the stator 2 by the air gap 23 is a rotor 3, which in this case has a squirrel cage, which is also arranged in a laminated core 12. The rotor 3 is connected in a rotationally fixed manner to a shaft 4 and rotates about the axis 5 during operation of the dynamoelectric machine 1.

[0053] FIG. 2 shows a basic longitudinal section of the drive 20, wherein the installation space 10 of the inverter modules 6 of the partial conductors 14, 15 or partial conductor bundles of the respective conductor bars 8 is arranged on the front side of the dynamoelectric machine 1. This construction according to the invention results in an extremely compact design of the entire drive 20, i.e., the dynamoelectric machine 1 with its inverter modules 6.

[0054] The inverter modules 6 are electrically connected to a DC voltage network or an intermediate circuit of a converter assigned to the drive 20.

[0055] FIG. 3 shows a detailed view of an end face of the dynamoelectric machine 1, in which the conductor bar 8 is divided into partial conductors 14, 15, and each partial conductor 14, 15 has its own inverter module 6. Of course, two, three, four, or more partial conductors 14, 15 of the conductor bar 8 can also be combined to form a partial conductor bundle and controlled or "supplied" by an inverter module.

[0056] This avoids the likelihood of semiconductor elements failing due to inaccuracies in the ignition pulse control. This is achieved primarily by placing the parallel connection of the partial conductors 14, 15 or partial conductor bundles in the conductor bar 8. Due to the low voltages (<100V), correspondingly small distances 30 are required between the inverter modules 6. These distances 30 allow, among other things, the inverter modules 6 to be cooled by a cooling air flow during operation of the drive 20.

[0057] FIG 4 shows a conductor bar 8 in which the partial conductors 14, 15 are arranged radially one above the other in the groove 18 and each partial conductor 14 is electrically connected to its inverter module 6 via a connection element 17.

[0058] FIG. 5 shows a further conductor bar 8 in which the partial conductors 14 are arranged radially in pairs one above the other in the groove 18. In this case, each partial conductor 14 or partial conductor bundle is again electrically connected to its associated inverter module 6 via a connecting element 17, e.g., via plug-in, screw-in, solder-in, or welded connections.

[0059] FIG 6 shows a further possibility of the partial conductor arrangement, which differs from the partial conductor arrangement according to FIG 4 only in that the partial conductors 14 are provided with a special insulation layer 16.

[0060] The partial conductors 14 according to FIG 7 are arranged like the partial conductors 14 according to FIG 5 and are provided with an insulation layer 16.

[0061] FIG 8 shows a conductor bar 8 whose radially arranged partial conductors 15 are hollow and are also contacted with their respective inverter module 6 via connection elements 7.

[0062] FIG 9 shows a conductor bar 8 whose partial conductors 15 arranged radially next to one another in pairs are also hollow.

[0063] Hollow partial conductors 15 have the advantage that, if necessary, a cooling fluid can be passed through these partial conductors 15. All partial conductors - designed as solid partial conductors 14 or hollow partial conductors 15 - can have an insulation layer 16 (plastic layer or lacquer layer) or can be bare. However, even with bare partial conductors 14, 15, an oxide layer is present, which should be sufficient for insulation within the groove 18 due to the comparatively low voltage potentials between the partial conductors 14, 15 during operation of the drive 20.

[0064] FIG. 10 shows a longitudinal section through a basic arrangement of inverter modules 6 on partial conductors 14, 15 of a conductor bar 8. The partial conductors 14, 15 have axially different lengths in the axial extension of the conductor bar 8, i.e., parallel to the axis 5, in order, among other things, to generate a distance 30 between the inverter modules 6.

[0065] FIG. 11 shows, in a longitudinal section, another basic arrangement of inverter modules 6 on partial conductors 14, 15 of a conductor bar 8. The partial conductors 14, 15 have axially different lengths, with the ends of the partial conductors 14, 15 preferably being bent radially outward in order to position and contact the inverter modules 6 there. This allows, among other things, a distance 30 between the inverter modules 6 to be created, which improves the cooling of the inverter modules 6 and also simplifies assembly.

[0066] FIG. 12 shows a plan view of a basic arrangement of inverter modules 6 on partial conductors 14, 15 of a conductor bar 8. The view is directed radially to the axis 5. The conductor bar 8 is formed, for example, from partial conductors 14, 15 according to FIGS. 5, 7, 9, in that the radial height in a groove 18 is taken up by two partial conductors 14, 15 arranged next to one another. The partial conductors 14, 15 are arranged next to one another viewed in the circumferential direction - for example as in FIG. 10. In other words: each radial layer of partial conductors 14, 15 in a groove 18 has a different axial length with respect to another radial layer, the inverter modules 6 then being located at the ends of these respective partial conductors 14, 15. The inverter modules 6 of the partial conductors 14, 15 in radially different layers of the partial conductors 14, 15 are arranged axially and radially offset.

[0067] FIG 13 shows a structure similar to the structure of FIG 12 , but the inverter modules 6 of partial conductors 14 , 15 are also arranged offset in a radial layer.

[0068] The arrangements shown are exemplary and can also refer to more than two partial conductors per radial layer in a groove 18. Likewise, inverter modules 6 for individual partial conductors 14, 15 can also be arranged for partial conductor bundles, i.e. partial conductors 14, 15 connected electrically in parallel, in accordance with the above explanations.

[0069] In further embodiments, the above-mentioned partial conductors 14, 15 and / or partial conductor bundles of the conductor 8 can be guided either in parallel or in a Roebeled manner over the axial length of the stator 2 or of the laminated core 11 of the stator 2. When Roebeled, the position of each partial conductor 14, 15 and / or partial conductor bundle is guided over the axial length in such a way that current displacement can be avoided. Viewed over the axial course of a slot 18, each section of the partial conductor 14, 15 and / or partial conductor bundle of the Roebeled conductor bar 8 now has the same average vertical position in the slot 18 over the axial slot length, so that the current density in all twisted parallel partial conductors 14, 15 and / or partial conductor bundles is approximately constant and current displacement is avoided.An increase in resistance caused by current displacement, which would inevitably be associated with increased ohmic losses, can thus be greatly reduced. Such a drive 20 is used in vehicle drives, such as ship drives, traction drives in rail transport, trucks and cars, as well as in industrial environments, particularly in compressors, or pumps, due to the compactness and easy adjustment of a wide speed range of the drive 20.

Claims

Patent claims 1. Drive (20) with a rotary dynamoelectric machine (1) with a stator (2) and a rotor (3), wherein the stator (2) has a winding system (7) in a magnetically conductive body, in particular a laminated core (11), wherein the stator (2) and rotor (3) are separated from one another by an air gap (23), wherein the winding system (7) is arranged in slots (18) of the magnetically conductive body, which slots face the air gap (23), wherein the winding system has a conductor bar (8) divided into partial conductors (14, 15) or partial conductor bundles per slot (18), the partial conductors (14, 15) or partial conductor bundles of which are electrically contacted at a first end of the conductor bar (8) with at least one inverter module (6) and the partial conductors (14, 15) or partial conductor bundles of which are electrically contacted at the other end, i.e. second end of the conductor bar (8) on the other end side of the magnetically conductive body of the stator (2) with the other partial conductors (14,15) or partial conductor bundles of the further conductor bars (8) arranged in the respective grooves (18) are combined to form a short-circuit ring (9).

2. Drive (20) according to claim 1, characterized in that several partial conductors (14, 15), in particular a partial conductor bundle of a conductor bar (8) are connected to an inverter module (6).

3. Drive (20) according to claim 1, characterized in that each partial conductor (14, 15) of a conductor bar (8) is connected to an inverter module (6).

4. Drive (20) according to one of the preceding claims, characterized in that the partial conductors (14, 15) or partial conductor bundles run parallel at least within the magnetically conductive body.

5. Drive (20) according to one of the preceding claims 1 to 3, characterized in that the partial conductors (14, 15) or partial conductor bundles change their position in the groove (18) in the axial course of the groove (18), at least within the magnetically conductive body, in particular are arranged in a Roebel manner.

6. Drive (20) according to one of the preceding claims, characterized in that the partial conductors (15) are solid or designed as waveguides.

7. Drive (20) according to one of the preceding claims, characterized in that the partial conductors (14, 15) or partial conductor bundles are provided at least in sections with an insulating layer (16) when viewed in the circumferential direction.

8. Drive (20) according to one of the preceding claims, characterized in that between two or more axially and / or radially arranged inverter modules (6), cooling elements (19) are provided between the inverter modules (6), which are at least partially in heat-conducting contact with the adjacent inverter modules (6).

9. Method for producing a stator (2) of a rotary dynamoelectric machine (1) having a winding system (7) in a magnetically conductive body, in particular a laminated core (11), by the following steps: - Manufacturing of the magnetically conductive hollow cylindrical Body, in particular the laminated core (11) of the stator (2) , wherein grooves (18) point towards the inner surface of the hollow cylindrical body, - Contacting of connecting elements (17) to a first axial end (7) of a conductor bar (8) of a groove (18) , wherein the conductor bar (8) is constructed from partial conductors (14, 15) which are individually and / or as partial conductor bundles with the connecting elements (17) and which run parallel or interlocked at least within the groove (18), - axial insertion of the partial conductors (14, 15) or partial conductor bundles of the respective conductor bars (8) provided with the connecting elements (17) into the respective grooves (18) of the magnetically conductive body or laminated core (11), - Contacting at least one short-circuit ring (9) at the second ends of the conductor bars (8) and positioning and contacting the inverter modules (6) to the partial conductors (14, 15) or partial conductor bundles of the conductor bars (8) provided with the connection elements (17).

10. Method for producing a stator (2) of a rotary dynamoelectric machine (1) according to one of claims 6 to 9, characterized in that existing insulation materials on the conductor bar (8), in particular the partial conductors (14, 15) or partial conductor bundles and / or connecting element (17) are removed, in particular burned away, at least in the region of their contact point by means of the contacting process.

11. Use of a drive (20) according to claims 1 to 5 or of a stator (2) manufactured according to one of claims 6 to 10, in a drive (20) in an industrial environment, in particular in compressors, compressors or pumps.

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