Vernier external rotor machine and motor system

A Vernier external rotor machine for direct drive of a load is provided. The Vernier external rotor machine includes an external rotor configured to mechanically directly drive to a load.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a national phase application of PCT International Application No. PCT/EP2017/054372, filed Feb. 24, 2017, which claims priority under 35 U.S.C. § 119 from German Patent Application No. 10 2016 203 616.5, filed Mar. 4, 2016, the entire disclosures of which are herein expressly incorporated by reference.

BACKGROUND AND SUMMARY OF THE INVENTION

The invention relates to a Vernier external rotor machine and to a motor system.

EP 0 155 877 A1 discloses a Vernier machine. The functional principle of Vernier machines of this kind is based on the use of magnetic flux modulators which cause a magnetic conductance which is dependent on the rotation angle. Otherwise, reference is also made to the relevant technical literature relating to Vernier machines.

The invention is based on the object of providing a Vernier machine and a motor system, which Vernier machine and motor system have properties which are improved in comparison to known Vernier machines.

The Vernier machine according to the invention is a Vernier external rotor machine, wherein the external rotor of the Vernier external rotor machine according to the invention is mechanically coupled directly, in particular without the interposition of a mechanical or any other gear mechanism, to a load or mechanical system to be driven, for example a drive belt or a drive chain. By way of example, the external rotor can form a driven roller within a conveyor element and/or a driven gear wheel.

The external rotor can be in the form of a drive roller or in the form of a gear wheel, wherein, for example, the load, to be driven, in the form of a drive belt or a drive chain runs around the drive roller or the gear wheel. The external rotor, that is to say the outer part of the rotor, can therefore serve directly for force transmission at the same time, for example form a running surface of a driven roller. Therefore, a direct drive structure can be realized.

The external rotor can be of non-laminated design. The external rotor can, for example, be composed of solid iron. An external rotor of this kind can be produced in a cost-effective manner in comparison to a laminated external rotor.

The stator can have a number of (for example between 3 and 20) stator teeth, wherein the stator teeth form a flux modulator of the Vernier external rotor machine. In this way, an additional modulator ring can be dispensed with. This leads to simple and compact geometries.

The air gap can be varied by means of a stator tooth or modulator tooth. A higher power factor, a higher torque density and lower torque ripple can be achieved in this way.

The motor system has an above-described Vernier external rotor machine. The external rotor is of anisotropic design, that is to say has, for example, (magnetic) properties which are dependent on a rotation angle position of the external rotor.

The motor system further has a device for determining a rotation angle position of the external rotor, wherein the device for determining a rotation angle position of the external rotor is designed to determine the rotation angle position of the external rotor depending on the anisotropy of the external rotor. The device for determining the rotation angle position of the external rotor can additionally evaluate motor currents and/or motor voltages for determining the rotation angle position.

The external rotor can have flux barriers for forming the anisotropy, in order to optimize the motor system, for example, for encoder-free control. By way of example, the flux barriers can be inserted into the rotor yoke.

The anisotropy and, respectively, the flux barriers can be formed, for example, by means of a tooth structure on an outer circumference of the external rotor, so that the external rotor can be used as an output drive for a toothed belt at the same time.

In order to form the anisotropy and, respectively, the flux barriers, the rotor can be structured, for example, in a simple manner from the outside, for example standard pipes which are subject to machining can be used. The resulting external anisotropy can be used, for example, as a toothed rim in order to drive a toothed belt for example.

The drive system can have a load to be driven, wherein the external rotor of the Vernier external rotor machine is mechanically coupled directly to the load to be driven.

The drive system can have a frequency converter which is designed to generate drive signals for the windings of the stator of the Vernier external rotor machine in such a way that a desired rotation speed and/or a desired torque of the Vernier external rotor machine are/is established.

The Vernier external rotor machine can have a housing into which parts of the Vernier external rotor machine, for example mechanical bearings, electrical connecting lines etc., are integrated.

The frequency converter can be arranged on the outside of the housing, for example mounted onto the housing, or mechanically coupled to the housing in axial extension of a motor shaft. As an alternative, the frequency converter can be arranged inside the housing.

The frequency converter can be designed to convert any braking energy of the load to be driven which may be present into thermal energy by generating the drive signals for the windings of the stator of the Vernier external rotor machine in such a way that a radiofrequency magnetic alternating field is induced in the external rotor, said radiofrequency magnetic alternating field generating heat in the external rotor. In other words, the braking energy is converted into thermal energy in the external rotor. In this case, the external rotor is not laminated or is a solid-iron external rotor.

The device for determining a rotation angle position of the external rotor can be integrated into the frequency converter and/or connected in a signal-transmitting manner to the frequency converter.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1shows a schematic cross section through a drive system6according to an embodiment of the invention comprising a Vernier external rotor machine1.

An external rotor2of the Vernier external rotor machine1is mechanically coupled directly to a load3to be driven in the form of a toothed belt. Here, the external rotor2is in the form of a gear wheel which directly drives the toothed belt3.

The external rotor2is not laminated and is composed of solid iron. A number of permanent magnets9with the illustrated polarity is arranged on an inner side of the external rotor2.

The external rotor2has flux barriers8for forming an anisotropy. The flux barriers8are formed as teeth or a tooth structure in the solid iron and are uniformly distributed over the circumference of the external rotor2.

An angle coding can also be realized by means of the flux barriers8, wherein the flux barriers8, in contrast to the manner illustrated inFIG. 1, are of angle-dependent design for this purpose.

The stator4of the Vernier machine1has12stator teeth5. The modulator ring which is usually used is therefore integrated into the stator4and can be dispensed with. Windings10are associated with the stator teeth5in each case, that is to say the stator has a 3-phase, concentrated winding system.

The motor system6has a device7for determining a rotation angle position of the external rotor2, wherein the device7for determining the rotation angle position of the external rotor2is designed to determine the rotation angle position of the external rotor2depending on the anisotropy of the external rotor2. To this end, the device7can have, for example, a Hall sensor12which generates a signal which is dependent on the anisotropy and is evaluated by means of the device7for determining the rotation angle position.

FIG. 2ashows a first variant of the drive system according to an embodiment of the invention fromFIG. 1, which drive system is otherwise designed in the manner shown inFIG. 1. The motor system6has a frequency converter13which is designed to generate drive signals, for example in the form of drive voltages/drive currents with an adjustable amplitude/frequency, for the windings10of the stator4of the Vernier external rotor machine1.

The Vernier external rotor machine1has a housing14, for example composed of metal. The frequency converter13has a dedicated housing15which is mounted onto the housing14of the Vernier external rotor machine1and is mechanically coupled to said housing.

The frequency converter13is designed to convert any braking energy which may be present into thermal energy by generating the drive signals for the windings10of the stator4of the Vernier external rotor machine1in such a way that a radiofrequency magnetic alternating field is induced in the external rotor2which is not laminated for this case.

The device7, shown inFIG. 1, for determining a rotation angle position of the external rotor2is integrated into the frequency converter13. This allows encoder-free control by the converter13.

FIG. 2bshows a further variant of the drive system according to the invention fromFIG. 1, in which drive system, based on the variant illustrated inFIG. 2a, the frequency converter13is mounted in axial extension onto the housing14. Otherwise, the statements made in relation to the embodiment fromFIG. 2acorrespondingly apply.

FIG. 2cshows a further variant of the drive system according to the invention fromFIG. 1, in which drive system, based on the variant illustrated inFIG. 2a, the frequency converter13is arranged inside the housing14. Otherwise, the statements made in relation to the embodiment fromFIG. 2acorrespondingly apply.

The motor systems6shown inFIGS. 2ato 2ccontain all of the required drive components in prefabricated form, so that a user of the motor system6can integrate said motor system into a drive application directly and without further expenditure on assembly/interconnection.

The converter (electronics) can be attached to the Vernier external rotor machine, for example mounted onto the machine in a dedicated housing, inserted into the motor housing of the machine or axially attached to the machine (in a rigid, rotating manner).