Electric machine with a detection system, drive unit, vehicle

Abstract

The disclosure relates to an electrical machine (100) comprising: a stator (110), a rotor (160), at least one coil (120) configured to generate a magnetic interaction between the stator (110) and the rotor (160), and a detection system (200) configured to detect a fault (F) of the electrical machine (100), in particular a short circuit in the at least one coil (120), characterized in that the detection system (200) comprises an optical waveguide (210) and at least one optoelectronic receiver (220) optically coupled to the optical waveguide (210), configured to detect the fault (F) based on an optical detection of light emissions (L) caused by the fault (F).

Description

[0001] The present disclosure relates to an electric machine, a drive unit and a corresponding vehicle, in particular an aircraft.

[0002] Fuel consumption, emissions, and operating costs are driving new applications of electric machines in vehicles, especially aircraft. Auxiliary electric power units, hybrid drive systems, and all-electric drives are based on electric machines with the highest power densities and maximum safety requirements. Arcs can occur as a precursor to or as a consequence of a short circuit in an electrical machine. They can occur, for example, at points where a winding is inadvertently interrupted or short-circuited, such as at connecting rings or terminals.

[0003] Radiation is the primary energy transfer mode in arc flashes. An arc flash instantly releases large amounts of radiant energy (typically in a wavelength range of 0.1 nm to 100 nm), including both light and heat energy. If an arc flash is not detected and controlled in time, it can cause a fire, damage equipment, and even physical injury. Typical damage includes overheating and melting of the winding, as well as toxic outgassing. Overheating of nearby coolants also leads to a dangerous pressure increase, which can lead to an explosion in the coolant compartment. Therefore, arc flash detection and mitigation are essential for the safe operation of electrical machines, especially those used in aviation applications.

[0004] Conventional arc fault detection devices use microprocessor technology to analyze the waveform of electrical quantities (e.g., current or voltage), which is used to detect unusual signal signatures. However, these line-signal-based methods cannot detect line-to-ground (parallel arc) or line-to-neutral (series arc) faults. Furthermore, temperature sensor-based methods are used in industry because of their simplicity and low cost. However, they suffer from a low detection rate, where a fault is detected based on a nearby but indirect temperature rise. Sudden pressure protection devices are often used in transformers to prevent an overpressure accident. Once an arc fault is detected, the relay mechanism is triggered by a trip command.Although they allow for rapid pressure relief, their size and weight make them unsuitable for applications in, for example, aerospace.

[0005] In principle, systems for detecting arc faults, for example, are known from US 7,035,068 B2 or US 7,580,232 B2.

[0006] The object of the present invention is to at least partially solve the problems mentioned with reference to the prior art.

[0007] The problem is solved by an electric machine, a detection system, a drive unit, and a corresponding vehicle, in particular an aircraft, according to the independent claims. Advantageous further developments are specified in the subclaims.

[0008] The invention is based on an electrical machine for at least one electrical drive unit, comprising: a stator, a rotor, at least one coil designed to generate a magnetic interaction between the stator and the rotor, and a detection system designed to detect a fault in the electrical machine, in particular a short circuit in the at least one coil.

[0009] According to the invention, the detection system comprises an optical waveguide and at least one optoelectronic receiver optically coupled to the optical waveguide, which is designed to detect the error on the basis of an optical detection of light emissions caused by the error.

[0010] The invention includes the finding that the detection system of an electrical machine of a drive unit is designed such that an occurring fault, for example in the form of a short circuit or an arcing fault, can be detected. The fault can be detected using at least one optoelectronic receiver, which is in particular a sensor. The fault can occur in the form of a light emission, which is for example an arcing fault, and can be optically detected. The optoelectronic receiver is optically coupled to at least one optical fiber. The light emission caused by a fault can be detected in real time, in particular at a speed such that the fault does not cause a malfunction or damage to the machine.

[0011] The solution includes a detection system that uses compact and fast optoelectronic detection of the defect.

[0012] The fiber optic cable runs through the machine, in particular in such a way that line of sight to potential fault zones can be guaranteed. This means, in particular, that the fiber optic cable is arranged in the electrical machine in such a way that light emissions can reach the fiber optic cable directly and / or indirectly, e.g. via reflective surfaces. Space-saving integration makes it possible to lay the fiber optic cable in or on the electrical machine in such a way that the largest possible area is covered for detecting faults. Such a detection system is easy to install and, if necessary, easy to expand. Due to its small size and simple design, the optoelectronic receiver can be easily integrated into an electrical machine without significantly compromising the installation space.Optoelectronic fiber optics can also be used in aggressive media such as plasma or radioactive media and operate with minimal error. Optoelectronic receivers are immune to electromagnetic interference and do not conduct electricity, allowing them to be used in locations where high voltage or flammable materials such as jet fuel are present.

[0013] Advantageous further developments of the invention can be found in the dependent claims and specify in detail advantageous possibilities for realizing the concept explained above within the scope of the task and with regard to further advantages.

[0014] In particular, the stator includes the coil.

[0015] One embodiment of the electrical machine is characterized in that the optical waveguide comprises one optical fiber or a plurality of optical fibers. The optical fibers can be of virtually any length. For example, the optical fibers can be made of glass, quartz, or plastic fibers. It can advantageously be ensured that, for example, an optical waveguide is also mechanically reinforced to protect and stabilize the individual optical fibers. For example, the length of an optical waveguide can be up to 80 m. Such an optical waveguide can offer high integration flexibility with low weight and cost.

[0016] A further embodiment of the electrical machine is characterized by a signal processing unit which is designed to detect the error and output an error signal as a function of an optical received signal.

[0017] The at least one signal processing unit can be coupled to the at least one optical fiber, via which the optical reception signal is transmitted. The at least one transmitted optical reception signal can be checked for validity by the signal processing unit. In particular, the signal processing unit can ensure that the occurring error, for example in the form of an arc flash or short circuit, which results in corresponding light emissions, is detected and transmitted as an optical reception signal at any location in the coil arrangement. The error signal is then output in the signal processing unit.

[0018] For example, the signal processing unit monitors the condition of the coils. An error indicates that, for example, one or more short circuits exist in the coil arrangement and a potentially impermissible system state has occurred.

[0019] A further embodiment of the electrical machine is characterized by a plurality of optical fibers, each coupled to the optoelectronic receiver and / or to another optoelectronic receiver. In particular, in further developments, each optical fiber can be optically coupled to an optoelectronic receiver. In this way, it is advantageously possible to assign a fault registered by an optoelectronic receiver to a spatial region and / or a functional unit (e.g., coil, lane, stator system, or partial winding system) of the electrical machine to which the corresponding optical fiber is assigned.

[0020] The plurality of optical fibers can advantageously be optically connected, in particular by thermal fusion, e.g., by splicing. This is advantageous in developments in which multiple optical fibers are coupled to an optoelectronic receiver. For example, a number of two or more optical fibers, or strands of optical fibers, can be spliced ​​together into one optical fiber, preferably at a distance from the optoelectronic receiver.

[0021] In such a development, any number of optical fibers with an optoelectronic receiver can be arranged in and / or around the stator system. It is particularly advantageous to arrange the optical fibers very close to the coils, since the occurrence of faults, for example in the form of arcing faults, can be detected particularly well there by the respective optoelectronic receivers. Various arrangements of optical fibers, in particular fiber arrangements, can be realized, which can be connected in series or parallel and have multiple turns, for example to increase the sensitivity and / or the exposure, i.e. the optically sensitive receiving area. Star topologies of fibers or fiber strands, in particular, have a point-to-point connection between the central optical fiber and the connected optoelectronic receiver.For example, this can have a beneficial effect on the speed of signal transmission and processing of detected errors. Other advantages of a star topology include the following: In particular, the effects of a single point of failure can be limited, and each connection of an optical fiber to the respective optoelectronic receiver can be considered isolated from other connections. If one connection fails, this has no impact on the performance of the other connections in the star topology arrangement. Another advantage is that it makes it easier to add or remove individual optical fibers from an arrangement.

[0022] In advantageous further developments, one of the plurality of optical fibers can be assigned to a subregion of the electrical machine, for example, a subregion of the stator, in particular arranged therein. A subregion can be, for example, a quadrant of the stator, or a so-called lane or similar partial winding system. In such further developments, the location of the fault can advantageously be localized, in particular if an optical fiber is assigned to a known region.

[0023] Alternatively or additionally, further developments may provide for at least two of the plurality of optical fibers to be arranged in a subregion of the electrical machine, in particular parallel and / or adjacent to one another. In such a further development, the redundancy of the detection system can advantageously be increased, for example, if an optical fiber is damaged.

[0024] The optoelectronic receiver is particularly designed to measure optical and / or electromagnetic radiation or fields that may arise, for example, from arc faults.

[0025] Another embodiment of the electrical machine is characterized in that the optical fiber is arranged parallel, in particular bifilar, with respect to the at least one coil. This has the advantage that the optical fiber can be positioned adjacent to a conductor of the coil, and thus to the potential source of the fault. Thus, the coil and optical fiber are arranged compactly with respect to one another. Such an arrangement also allows a large portion, in particular the entire length, of a coil conductor of the coil to be detected. Furthermore, the range of the optoelectronic receiver can also be increased. The parallel, in particular bifilar, arrangement can relate to an entire coil conductor or to a partial region of a coil conductor.

[0026] The invention further proposes that the electrical machine has a detection system that is designed to detect the error within a reaction time, wherein the reaction time is less than or equal to 1 millisecond, preferably less than or equal to 1 microsecond, particularly preferably less than or equal to 100 nanoseconds.

[0027] The detection system comprises an optical fiber and at least one optoelectronic receiver optically coupled to the optical fiber, wherein the optoelectronic receiver is designed to achieve a fast electronic response time to an occurring fault. The detection system can have a response time of preferably <100 ns. The response time includes an evaluation time of a signal processing unit. By shortening the response time and thus the fault exposure time, the destructive energy of, for example, high-current discharges with strong ohmic heating and the probability of fault propagation can be limited. The lane control unit (LCU) can advantageously be designed, in the case of an electrical machine with multiple phases and / or lanes, for example, to switch the faulty phase and / or lane to a weakened FOS state (Fail-Operational State).If the detection mechanism reacts quickly enough, the propagation of faults can be prevented and sub-machine operation can be ensured. Response time is a critical factor for detecting faults quickly and robustly. Processing time is advantageously kept short, e.g., through analog and / or correspondingly fast signal processing.

[0028] Another embodiment of the electrical machine is characterized in that the optoelectronic receiver is designed to detect light emissions in a wavelength range of 300 to 1500 nm, preferably in a range of 500 to 1000 nm, particularly preferably in a range of 650 to 850 nm.

[0029] To detect light emissions, for example in the form of an arc fault, optoelectronic receivers can be used in a known manner. These receivers evaluate the wavelength and light intensity of the radiation of the detected light emission. In particular, faults, e.g., an arc fault, generate strong light emissions, which can be several orders of magnitude stronger than the ambient light. In particular, the wavelength range of light emissions, e.g., of an arc fault, is 300 nm to 1500 nm. The optoelectronic receiver can advantageously be designed to register light emissions in this wavelength range, e.g., in the range from 600 nm to 850 nm, preferably from 650 nm to 820 nm. Alternatively, the optoelectronic receiver can be designed to detect light emissions of a specific wavelength, e.g., 650 nm or 820 nm.Such light emissions can be detected and localized in real time by the optoelectronic receiver. The wavelength range of an arc fault is generally between 300 nm and 1500 nm.

[0030] In this wavelength range, various types of optical fibers, especially optical fibers, can be used. In particular, the optical fiber is made of glass fiber. In particular, the optical fiber is made of plastic. In particular, the optical fiber comprises one or more multimode fibers, especially multimode glass fibers.

[0031] One embodiment is characterized in that the electric machine has at least one reflection surface configured to reflect the light emissions, wherein the reflection surface is arranged and configured to receive light emissions and to reflect them as reflected light emissions to the optical waveguide. In such a development, the reception of light emissions by the detection system can advantageously be improved.

[0032] In a further development, at least one focusing lens is provided which is designed to focus light emissions from an area, in particular an area with an increased probability of occurrence of errors, in the direction of and / or onto the optical waveguide.

[0033] In a further development of the invention, it is provided that the optical fiber is arranged at least partially in and / or on the rotor of the electric machine. In particular, the electric machine in such developments can be designed as a separately excited machine. This means, in particular, that the optical fiber or parts of the optical fiber are designed to be movable relative to the stator, namely, rotatable along with the rotational movement of the rotor.

[0034] In further developments with an optical waveguide that is at least partially movable relative to the stator, at least one fiber optic slip ring or one fiber optic rotary joint can advantageously be provided. Using such devices, a static, i.e., non-movable, part of the optical waveguide or the optoelectronic receiver can be connected to a movable part of the optical waveguide, or to a fully movable optical waveguide, for transmitting optical signals, in particular optical reception signals or reference signals.

[0035] For separately excited electrical machines that have one or more slip rings for transmitting electrical power and / or signals, the optical fiber can advantageously be arranged in the area of ​​the slip rings, particularly within line of sight. This allows faults in this area to be detected by the detection system.

[0036] Various machine topologies can be equipped with fiber optic cables, e.g., integrating the fiber optic cables into the end winding areas of the stator system or into the NDE (non-drive end) or DE (drive end) end shield. To maximize the accessibility of the optoelectronic receiver, reflective surfaces (also on rotating parts) can be installed to direct arc fault rays toward the fiber optic cable. Translucent insulation and / or potting materials, especially for the coil, further help maximize sensor exposure and / or guide the light more effectively from the fault location to the fiber optic cable. The fiber optic cables can also be distributed over a large area, for example, in the form of a fiber optic network.

[0037] A further development of the electrical machine provides that the at least one coil at least partially has translucent insulation. The term "translucent" or "translucent insulation" can be understood in various exemplary embodiments to mean that an insulation is permeable to light, for example to the light generated by the light-emitting defect, for example in one or more wavelength ranges. In general, translucency is advantageous wherever light is to shine through a material, in particular to detect a short circuit, for example. Translucent insulation can serve to make an occurring defect or light emission at the coils more quickly detectable for the detection system, thus shortening the reaction time and averting a malfunction or damage to the electrical machine in good time.

[0038] A further development of the electrical machine provides that the optical waveguide at least partially has a sheath which is in particular opaque, and / or the electrical machine has at least one partition wall which is arranged and designed to shield the optical waveguide against interference.

[0039] The term "opaque sheathing" refers specifically to a sheathing that is impermeable to light. An opaque sheathing can be used to shield areas of the optical fiber where no light coupling is desired from external light influences. Areas of the optical fiber where detection of light emissions is desired, however, can be provided without sheathing.

[0040] In further developments, at least one partition wall can be provided, which is arranged and designed to shield the optical fiber from any optical interference, such as stray light, which could impair the detection of defects. The partition wall is preferably opaque.

[0041] A further development of the electric machine provides for the optical fiber to be in contact with a cooling medium of the electric machine, wherein the cooling medium is, in particular, translucent. In particular, the cooling medium is liquid.

[0042] Optical fibers, in particular, are insensitive and do not react with the medium in which they are located. In further developments, the electrical machine can have a cooling medium that is, in particular, translucent. For the detection and transmission of light emission, it is advantageous for the cooling medium to be translucent. Indirect air-cooled and direct oil-cooled machines are examples of electrical machines in which an optical process is possible with a highly transparent cooling medium. In particular, translucent also includes transparent.

[0043] According to a further embodiment of the electrical machine, the detection system has a further, in particular non-optical, sensor for providing a further received signal, wherein the detection system is designed to detect the error on the basis of the optical received signal and the further received signal.

[0044] In particular, the detection system can also comprise further, particularly non-optical, sensors in addition to the optoelectronic receivers. These further, particularly non-optical, sensors can contribute to even better detection of the fault through an additional received signal. The non-optical sensor can, for example, be designed to provide a pressure and / or a sound wave and / or an electrical signal. The non-optical sensor can advantageously be provided in addition to the optoelectronic receiver, for example, for plausibility checks and / or verification of the optical received signal. Alternatively or additionally, the non-optical sensor can serve as a backup system. In particular, to improve the detection reliability of the detection system, the detection system based on the optoelectronic receiver can be paired with a non-optical sensor.Such a non-optical sensor can, for example, be based on conventional overcurrent detection methods, which can be implemented, for example, on an AC interface.

[0045] According to a further development, the electric machine has several electrically independent stator systems or lanes. Advantageously, each stator system is assigned a detection system and / or an optoelectronic receiver. In this way, each stator system can be monitored by an independent detection system.

[0046] Electrical machines can have independent stator systems, with each stator system having its own detection system and / or its own optical fiber. Stator systems are also called base windings and can be electrically independent of one another.

[0047] The invention further proposes that the electric machine has a detection system which, after detecting the fault, switches the electric machine and / or the stator system into a safe operating mode or switches it off.

[0048] Preferably, the detection system is configured to initiate measures in response to a detected fault that ensure the safe operation of the electrical machine and / or prevent damage. For example, the detection system can be configured to switch the electrical machine to a corresponding safe operating mode and / or shut it down completely. The fault can be detected, in particular, using fast and comprehensive data acquisition and an anomaly detection algorithm (possibly implemented on a high-performance DSP (digital signal processor) and / or a real-time FPGA (field-programmable gate array)). Data-based classification methods using machine learning (ML) can be used to detect faults, such as anomalies or short circuits.As soon as a fault is detected by the arc fault detection device, the electrical machine or a section of the electrical machine or a stator system is transferred to the "fault detected" state, which can automatically put the electrical machine into a reduced power state or even turn it off completely.

[0049] The invention further proposes that the detection system comprises an optoelectronic transmitter optically coupled to the optical waveguide, which is designed in particular to provide an optical reference signal.

[0050] The detection system can comprise an optoelectronic transmitter that has an optical coupling to the optical fiber. The optoelectronic transmitter is advantageously arranged at the end of the optical fiber opposite the optoelectronic receiver. The optoelectronic transmitter is designed to generate an optical reference signal that can be conducted by the optical fiber and detected by the optoelectronic receiver. A change in the optical reference signal can be detected by the optoelectronic receiver. Depending on the type and classification of the reference signal, the detection system can initiate countermeasures, such as shutting down the electrical machine.

[0051] A further development is characterized in that the detection system is designed to determine a further state variable, in particular for characterizing a temperature, a mechanical stress and / or strain, as a function of the optical reference signal.

[0052] The detection system can be designed in such a way that, based on the received reference signal, it is able to determine a further state variable, which can be used to characterize a temperature, a mechanical stress and / or a strain. If a strain and temperature distribution and / or mechanical stress are of interest, optoelectronic measuring methods can also provide such information if the optical fibers are in contact with the machine component to be monitored and / or are even integrated therein. Physical variables, such as strain, vibration or temperature on, for example, a coil of the electrical machine, can be measured, for example, by evaluating optical signals backscattered from an optical fiber. In contrast to electrical detectors, e.g. current or voltage probes, optoelectronic measuring principles are not subject to phenomena of electrical measuring principles, such as, for example,electrical heating or additional ohmic losses. In addition, optical fibers are naturally immune to electromagnetic interference (EMI), which makes them robust against many environmental influences and requires little maintenance. The optical fiber can advantageously be in partial or complete contact with the component to be monitored. In this way, physical variables such as temperature in the component can be recorded as accurately as possible. The optical fiber can advantageously be firmly connected to the component to be monitored, in particular glued. In this way, the change in length of the component in the direction of the optical fiber can be recorded to determine mechanical parameters, in particular strain, mechanical stress and / or vibrations.To determine the physical quantities and / or errors, the optoelectronic receiver and / or the signal processing unit can be configured to spectroscopically process optical received signals and / or reference signals. Alternatively or additionally, the optoelectronic receiver and / or the signal processing unit can also comprise further optical elements, e.g., filters for evaluating optical signals. A filter can be, for example, a fiber Bragg grating, or include one.

[0053] A second aspect of the invention relates to a drive unit comprising an electric machine according to the first aspect. Regarding the advantages, reference is made to the above information.

[0054] A third aspect of the invention relates to a vehicle, in particular an aircraft, comprising at least one drive unit according to the first aspect of the invention and / or an electric machine according to the second aspect of the invention. For example, the aircraft, in particular an aircraft, has a plurality of drive units and / or electric machines that comprise a detection system. In particular, each drive unit and / or machine has at least one detection system. The invention can preferably be used in airborne electronic drive and / or energy storage systems.

[0055] In the following, the disclosure is described, without being limited thereto, by way of example, using exemplary embodiments and the accompanying figures, wherein identical system components are provided with identical reference numerals. Here, in the form of schematic representations: Fig. 1 a schematic sectional view through a stator of an electrical machine with a coil arrangement according to a first embodiment; Fig. 2A, Fig. 2B, Fig. 2C Examples of optical fiber shapes; Fig. 2 a perspective view of an electrical machine in simplified form with a detection system; Fig. 3 a perspective view of an aircraft with propulsion units; Fig. 4 is a schematic sectional view according to a second embodiment of the present invention; Fig. 5 a schematic representation of a detection system with a splice connection; Fig. 6A shows an embodiment of an electrical machine with a static optical fiber; Fig. 6B an embodiment of an electrical machine with a movable optical fiber.

[0056] In the Fig. Figure 1 schematically shows a sectional view through a stator 110 of an electric machine 100 as one embodiment of a drive unit 300. The stator 110 has several, in particular electrically independent, stator systems 118, of which one stator system 118 is shown with an arrangement of coils 120. A rotor 160 is rotatably mounted within the stator 110 to implement a rotational movement R.

[0057] The stator 110 comprises stator teeth 114, each with a coil 120 wound thereon. The coils 120 can, as shown schematically here, have translucent insulation 124 at least in regions. The stator teeth 114 extend inward toward the rotor 160 at equal intervals along a radial direction RR. The stator 110 and rotor 160 are shown elongated in the radial direction RR. This means that the curvature or circular shape typical of a rotary electrical machine 100 is not shown in the partial illustration shown here for reasons of clarity. In the electrical machine 100 of the embodiment shown, a coil 120 is wound in nine turns 121 around each stator tooth 114. An axial direction RA is perpendicular to the plane of the drawing.

[0058] The stator 110 of the electric machine 100 has, in the radial direction RR, a cylindrical stator wall 112 on the inside, on the side facing the rotor 160. This wall virtually hermetically seals a stator interior 115 of the stator 110 surrounding the stator teeth 114 and coils 120. The stator interior 115 thus forms a fluid-tight installation space 180 with defined fluid interfaces for accommodating a cooling medium 116. The illustrated components of the embodiment are in contact with a cooling medium 116. In the present case, the cooling medium 116 is liquid. The cooling medium 116 has a translucency that enables detection of light emissions L from the location of a fault F through the cooling medium 116 to the optical fiber 210. Nevertheless, within the scope of the invention, embodiments with other cooling approaches, for example with a gaseous cooling medium 116 such asAir is conceivable, in which in particular no hermetic stator interior 115 is required.

[0059] In the Fig. 1 shows a detection system 200 comprising a signal processing unit 240 with an optoelectronic receiver 220, wherein the optoelectronic receiver 220 is coupled to an optical fiber 210. The detection system 200 can optionally, as shown here, comprise an optoelectronic transmitter 230 coupled to the optical fiber 210 and preferably arranged at an end of the optical fiber 210 opposite the optoelectronic receiver 220. The optical fiber 210 is laid in a first configuration 216A around the stator teeth 114 and the coil 120 wound thereon.

[0060] The optical waveguide 210 has at least partially a sheath 214, which is particularly opaque. The sheathing can be used to make regions of the optical waveguide specifically insensitive to light emissions. In particular, regions of the optical waveguide 210 without a sheath 214 can be provided in which targeted detection of defects F or light emissions L is to take place. In addition to or as an alternative to the sheath 214, a partition 228 can also be provided, as is the case here, to shield the optical waveguide from unwanted interference SE, such as stray light.

[0061] In principle, it is possible, in particular by selecting a suitable profile shape 216, to adapt the profile of the optical waveguide 210 to the available space, in particular the installation space 180, so that the representation of the Fig. 1 is to be understood here only as an example.

[0062] When a fault F occurs, for example a short circuit and / or arc fault, a light emission L occurs that propagates into the environment through media that are at least partially translucent, for example air and / or, as here, coolant. Due to a suitable shape of the optical waveguide 210, the propagating light emission L encounters the optical waveguide 210 at at least one point and is coupled into it. From there, the light emission L is guided as an optical signal S through the optical waveguide 210 to the optoelectronic receiver 220. The optical receiver 220 is designed to register the optical signal S. The optical receiver 220 can in particular comprise a photosensitive element, for example a photodiode, which is designed to convert light into an electrical current.In the present case, the optical receiver 220 is connected to a signal processing unit 240, so that the electrical current generated and provided by the optical receiver 220 based on the optical signal S is received by the signal processing unit 240. The signal processing unit 240 is configured to output an error signal FS when the electrical current is present or received. For example, the signal processing unit 240 can be configured to output an error signal FS when the electrical current exceeds a threshold value. However, other signal processing methods can also be used additionally or alternatively to determine the error signal FS in the signal processing unit 240, for example pattern recognition and / or machine learning. The signal processing unit 240 is configured as a digital signal processor (DSP), namely advantageously as a real-time FPGA.The advantage of such a hardware-implemented implementation of the signal processing unit 240 lies in the fast processing and thus reaction time of the detection system 200.

[0063] In embodiments, as shown here, the electric machine 100 may have one or more reflection surfaces 260. For example, a surface of the stator wall 112 facing the stator 110 may be reflective and thus formed as a reflection surface 260. The reflection surface 260 is in Fig. 1 is only partially shown. In the present example, it is shown that when a fault F occurs at a location on the coils 120 in the form of a light emission L, the reflection surface 260 is arranged in the installation space 180 between the stator teeth 114 and the rotor 160 in such a way that a reflected light emission L' is generated and can be reflected toward the optical waveguide 210. The optical waveguide 210 transmits the reflected light emission L' as an optical reception signal S to the optoelectronic receiver 220, where the optical reception signal S is processed as described above.

[0064] The detection system 200 can, as shown here, comprise an optoelectronic transmitter 230 which is designed to generate an optical reference signal RS. Such an optical reference signal RS can, for example, be used to determine a further state variable ZS in addition to the detection of errors F by means of light emissions L. The optical transmitter 230 is designed to provide the optical reference signal RS continuously or intermittently, for example at regular time intervals or during defined events or on request. By coupling the optoelectronic transmitter 230 to the optical waveguide 210, the optical reference signal RS is transmitted to the optoelectronic receiver 220. The signal processing unit 240 can be designed toto process a current resulting from the optical reference signal RS, and to determine, on this basis, a further state variable ZS, in particular for characterizing a temperature, a mechanical stress, and / or strain. Such embodiments include the idea that a change in the physical properties in the environment of the optical waveguide 210 also changes the properties of the optical waveguide 210 with regard to the transmission of the optical reference signal RS, for example, with regard to the amplitude, frequency, and / or other properties.

[0065] In order to further increase the reliability in detecting faults F, embodiments, as shown here, can have a further, in particular non-optical, sensor 270. The further sensor 270 is designed to receive a further received signal WS, specifically when a fault F is present. In the present case, the further sensor 270 is connected to a current transformer 108 of the electrical machine 100 in a signal-carrying manner and is designed to detect an overcurrent US. The current transformer 108 is designed to supply the stator 110 with electrical energy and / or to receive electrical energy from it. Accordingly, in many cases a fault F, for example in the form of a short circuit or an arc, also manifests itself in signals from the current transformer 108, for example in the form of an overcurrent US.By having both the optical received signal S and the further received signal WS available for detecting the error in such cases, the reliability of error detection can be advantageously increased. The combination of the optical received signal S and the further received signal WS for detecting the error F by the signal processing unit 240 can be carried out in a manner familiar to those skilled in the art, for example, in the form of a Boolean OR operation, a Boolean AND operation, and / or other suitable methods of sensor data fusion.

[0066] The signal processing unit 240 is designed to communicate via a communication line 242 with a machine controller 106 of the electric machine 100 and / or the current transformer 108, for example in order to initiate measures such as a fail-safe mode of the electric machine 100 or a shutdown of a stator system 118 in the event of a fault F.

[0067] Fig. 2A to Fig. 2C show different exemplary profile shapes 216A-D for an optical waveguide 210, which can be used as is or in modified form and / or in combination with one another in embodiments of the invention. In general, it is advantageous to select a profile shape 216 for the optical waveguide 210 such that no, or as little as possible, shadowing occurs with respect to regions in which a defect F is to be detected. For example, a profile shape 216 can advantageously be designed meandering or in bays, like the first profile shape 216A (shown in dash-dotted lines) or the second profile shape 216B.

[0068] The first trajectory shape 216A is arranged practically in an axial plane in an end winding region 123A, 123B, preferably such that the optical waveguide 210 oscillates in bays from the inside to the outside in the radial direction RR. Preferably, the optical waveguide 210 of the first trajectory shape 216A is arranged in a first end winding region 123A and additionally in an axially opposite second end winding region 123B.

[0069] The second profile shape 216B (shown in dash-double-dotted lines) is similarly designed to oscillate in the radial direction RR, but in a plane between two adjacent stator teeth 114.

[0070] The third configuration 216C and the fourth configuration 216D are bifilar arrangements in which the optical waveguide 210 runs parallel to the turns 121 of the coil 120. In the third configuration 216C, the optical waveguide 210 is arranged outside the coil 120, in the radial direction RR at approximately the same height as the turn 121. In the fourth configuration 216D, the optical waveguide 210 is arranged inside the coil 120, specifically between two adjacent turns 121 in the radial direction RR.

[0071] For reasons of clarity, the third and fourth waveforms 216C, 216D are shown for only one turn 121. In particular, in the third and fourth waveforms 216C, 216D, the optical waveguide 210 runs completely parallel to all turns 121 of the coil 120.

[0072] In the Fig. 3, the electrical machine 100 is made of Fig. 1 is shown in a perspective view. By way of example, the detection system 200 and its signal processing unit 240 are mounted in a simplified form on the periphery of the electrical machine 100. Also visible are the optoelectronic receiver 220 and the optoelectronic transmitter 230, which are coupled to the interior of the electrical machine 100 via the optical fiber 210. Furthermore, Fig. 3 shows, by way of example, a number of three stator systems 118, namely a first stator system 118.1, a second stator system 118.2 and a third stator system 118.3.

[0073] Fig. 4 shows, by way of example, a vehicle 400 in the form of an aircraft 402 with a fuselage 404, elevators 406 and wings 408 and six rotor units 410 mounted thereon which serve as drive units 300.

[0074] The aircraft 402 includes one or more electric machines 100 for driving the rotor units 410. The rotor units 410 include a plurality of rotor blades 412, in this example four or three rotor blades 412 each. In the example shown, the rotor blades 412 are mounted on a hub 414 to form a propeller 416. In alternative embodiments, the number of electric machines 100 and drive units 300 may vary. Alternatively or additionally, the aircraft 402 may also include an electric generator and / or a fuel cell as energy source(s).

[0075] Fig. Figure 5 shows a further embodiment. In contrast to the Fig. In the embodiment shown in Figure 1, the detection system 200 with its signal processing unit 240 has a plurality of optical fibers 210, namely a first optical fiber 210.1, a second optical fiber 210.2, and a third optical fiber 210.3. These can be arranged parallel to one another, whereby "parallel" is not necessarily to be understood in the geometric sense, but rather means that the individual optical fibers 210.1-3 run independently of one another and are coupled to the optoelectronic receiver 220. Optionally, in preferred embodiments, the individual optical fibers 210.1-3 can each be coupled to their own optoelectronic receiver 220. In the present case, this means that the first optical waveguide 210.1 is connected to a first optoelectronic receiver 220.1, the second optical waveguide 210.2 is connected to a second optoelectronic receiver 220.2, and the third optical waveguide 210.3 is optically connected to a third optoelectronic receiver 220.3. In such embodiments, by assigning optical fibers 210.1-3 and thus optoelectronic receivers 220.1-3 to specific regions of the electrical machine 100, it is advantageous to register in which region of the electrical machine 100 or of the stator system 118 a fault F has occurred. In the present case, the optical fibers 210.1-3 are arranged, for example, between adjacent stator teeth 114 or coils 120; however, any other configurations 216, for example, those shown in FIG. Fig. 2A to Fig. 2C, or combinations thereof, can be used within the scope of such embodiments. The arrangement of the optical fibers 210.1-3 can also be referred to as a star topology, since several optical fibers 210.1-3 are centrally combined to form an optoelectronic receiver 220, or, as shown here, several optoelectronic receivers 220.1-3. Such embodiments have the further advantage that a failure of one optical fiber 220 and / or optoelectronic receiver 220.1-3 has no effect on the rest of the coupled pairs. Advantages of a star topology arrangement are easy troubleshooting, unlimited expandability, and simple routing. Thus, redundancy is created between the optoelectronic receivers 220 to increase failure, functional, and operational reliability.

[0076] Fig. 5 shows a schematic representation of another embodiment of a detection system 200. The detection system 200 has a first optical waveguide 210.1, a second optical waveguide 210.2, and a third optical waveguide 210.3, which are optically coupled to a common optical waveguide 210 via a splice connection 222 for transmitting optical signals, in particular optical reception signals S. The splice connection 222 is produced in this case by thermally fusing the individual optical waveguides 210.1, 210.2, 210.3. By means of such an optical coupling of several parallel strands, several regions can advantageously be coupled to an optoelectronic receiver 220 via a common optical waveguide 210 for the purpose of detecting errors F.

[0077] Fig. 6A shows a further embodiment of an electrical machine 100 having a static optical fiber 210, i.e., connected to a non-movable part of the electrical machine 100, here to the stator 110. This corresponds in principle to the embodiments shown in the previous figures.

[0078] In contrast, Fig.6B shows an embodiment of an electrical machine 100 with an optical fiber 210 in the form of a movable optical fiber 218. This means that the movable optical fiber 218 is fixedly connected to a movable part of the electrical machine 100, in this case the rotor 160, or is arranged in and on the rotor 160. The movable optical fiber 218 thus rotates together with the rotor 160. For the optical connection of the movable optical fiber 218 to a static optical fiber 210, the detection system 200 has a fiber optic slip ring 224. This allows an optical coupling of the optical fiber 210 to the movable optical fiber 218 while simultaneously permitting relative movement between the two components.The electrical machine 100 shown is a separately excited electrical machine 100 and has corresponding rotor coils 162 in the rotor 160, which are electrically connected to the static part of the electrical machine 100 by means of a slip ring 164. In embodiments with a slip ring 164, this can also advantageously be monitored for fault F by means of the detection system 200 via an optical fiber 210. List of reference symbols 100 Electric Machine 106 Machine control 108 current transformers 110 Stator 112 Stator wall 114 Stator tooth 115 Stator interior 116 Cooling medium 118 Stator system 118.1-3 first to third stator system 120 spool 123A first end turn area 123B second end winding area 124 translucent insulation 160 rotor 162 rotor coil 164 slip ring 180 installation space / gap 200 detection system 210 optical fibers 210.1 first optical fiber 210.2 second optical fiber 210.3 third optical fiber 212 optical fibers 214 Sheathing 216 Shape of the optical fiber 216A-D first to fourth shape of the optical fiber 218 movable fiber optic cable 220 optoelectronic receiver 220.1 first optoelectronic receiver 220.2 second optoelectronic receiver 220.3 third optoelectronic receiver 222 splice connection 224 fiber optic slip ring 226 fiber optic swivel joint 228 Partition wall 230 optoelectronic transmitter 240 signal processing unit 242 Communication line 260 reflection surface 262 Focusing lens 270 additional sensor, non-optical sensor 300 drive unit 400 vehicles 402 aircraft 404 fuselage 406 Elevator 408 wings 410 rotor unit 412 rotor blade 414 Hub F Error FS error signal L Light emission L' Reflected light emission R rotational movement RA axial direction RT tangential direction RR radial direction RS reference signal S optical reception signal SE interference T Reaction time WS reception signal ZS state variable QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 7,035,068 B2

[0005] US 7,580,232 B2

[0005]

Claims

[1] Electrical machine (100), comprising: - a stator (110), - a rotor (160), - at least one coil (120) designed to generate a magnetic interaction between the stator (110) and the rotor (160), and - a detection system (200) designed to detect a fault (F) of the electrical machine (100), in particular a short circuit in the at least one coil (120), characterized by , that - the detection system (200) comprises an optical waveguide (210) and at least one optoelectronic receiver (220) optically coupled to the optical waveguide (210), which is designed to detect the defect (F) on the basis of an optical detection of light emissions (L) caused by the defect (F). [2] Electrical machine (100) according to claim 1, characterized bya plurality of optical waveguides (210.1, 210.2, 210.3), each coupled to the optoelectronic receiver (220), or to another optoelectronic receiver (220.1, 220.2, 220.3). [3] Electrical machine (100) according to claim 1 or 2, characterized by that the optical waveguide (210) is arranged parallel, in particular bifilar wound, with respect to the at least one coil (120). [4] Electrical machine (100) according to one of the preceding claims, characterized by in that the detection system (200) is designed to detect the error (F) within a reaction time (T), wherein the reaction time (T) is less than or equal to 1 millisecond, preferably less than or equal to 1 microsecond, particularly preferably less than or equal to 100 nanoseconds. [5] Electrical machine (100) according to one of the preceding claims, characterized bythat the optoelectronic receiver (220) is designed to detect the light emissions (L) in a wavelength range from 300 to 1500 nm, preferably in a range from 500 to 1000 nm, particularly preferably in a range from 650 to 850 nm. [6] Electrical machine (100) according to one of the preceding claims, characterized by a reflection surface (260) configured to reflect the light emissions (L), wherein the reflection surface (260) is arranged and configured to receive light emissions (L) and to reflect them as reflected light emissions (L') to the optical waveguide (210). [7] Electrical machine (100) according to one of the preceding claims, characterized by that the at least one coil (120) has at least partially a translucent insulation (124). [8] Electrical machine (100) according to one of the preceding claims, characterized bythat the optical waveguide (210) at least partially has a sheath (214) which is in particular opaque, and / or the electrical machine (100) has at least one partition wall (228) which is arranged and designed to shield the optical waveguide (210) against interference (SE). [9] Electrical machine (100) according to one of the preceding claims, characterized by that the optical waveguide (210) is in contact with a cooling medium (116) of the electrical machine (100), wherein the cooling medium (116) is liquid and in particular translucent. [10] Electrical machine (100) according to one of the preceding claims, characterized by that the detection system (200) has a further, in particular non-optical, sensor (270) for providing a further received signal (WS), wherein the detection system (200) is designed to detect the error (F) on the basis of the optical received signal (S) and the further received signal (WS). [11] Electrical machine (100) according to one of the preceding claims, characterized by that the electrical machine (100) has a plurality of electrically independent stator systems (118), wherein each stator system (118) is assigned a detection system (200) and / or an optoelectronic receiver (220). [12] Electrical machine (100) according to one of the preceding claims, characterized by that the detection system (200) is designed to switch the electrical machine (100) and / or the stator system (118) into a safe operating mode or to switch it off after detecting the fault (F). [13] Electrical machine (100) according to one of the preceding claims, characterized byin that the detection system (200) has an optoelectronic transmitter (230) which is optically coupled to the optical waveguide (210) and is designed to provide an optical reference signal (RS), in particular in that the detection system (200) is designed to determine a further state variable (ZS), in particular for characterizing a temperature, a mechanical stress and / or strain, as a function of the optical reference signal (RS). [14] Drive unit (300) comprising an electric machine (100) according to one of the preceding claims. [15] Vehicle (400), in particular aircraft (402), comprising at least one drive unit (300) according to claim 14 and / or an electric machine (100) according to one of claims 1 to 13.

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