Device for wireless electrical power and / or communication transmission for an electric machine, electric machine and drive system

Abstract

The invention relates to a device (100) for wireless electrical power and / or communication transmission for an electric machine (50), in particular for a separately excited synchronous machine, comprising at least a first transmission unit (10, 12) which is arranged stationary in spatial proximity to the electric machine (50), in particular on a housing (52) of the electric machine (50), and a second transmission unit (20, 22) which is arranged on a rotating part (54), in particular a shaft (56), of the electric machine (50). The first transmission unit (10, 12) and the second transmission unit (20, 22) are configured for capacitive and inductive coupling by means of electric and / or magnetic and / or coupled electromagnetic fields, wherein the first transmission unit (10, 12) and the second transmission unit (20, 22) are resonantly tuned to each other.The first transmission unit (10, 12) and the second transmission unit (20, 22) are optionally configured as a transmitting unit (14) or as a receiving unit (24) during operation of the electric machine (50). The invention further relates to an electric machine (50) with a device (100) and a drive system (200).

Description

The invention relates to a device for wireless electrical power and / or communication transmission for an electric machine, in particular for a separately excited synchronous machine, and to an electric machine, in particular for a separately excited synchronous machine, having such a device.Externally excited synchronous machines are increasingly to be used as electric machines in the automobile sector, since permanent magnets can be dispensed with in this motor concept. Here, a rotor with electric coils is used. Since the electrical power transmission to the rotor with carbon brushes is greatly subject to wear, an inductive energy transmission method is used for this purpose, for example.For example, in DE 10 2012 010 752 A1, for the realization of an electric machine, the excitation voltage of which can be adjusted from the stator side without complicated actuation of semiconductor switches, it is provided that the electric machine comprises a main machine and an excitation machine for supplying an excitation winding of the main machine with electrical energy. A first rotor of the exciter is connected in a rotationally fixed manner to a rotor of the main machine and comprises an induction winding. The exciter has a second rotor which is mounted such that it can be driven not only relative to the first rotor of the exciter but also relative to a stator of the main machine.WO 2020 / 185877 describes a bimodal system for resonant near-field wireless electrical power transmission configured for simultaneous capacitive power transmission and inductive power transmission according to an adjustable transmission mode ratio at a resonant power signal oscillation frequency. The system includes a transmitter subsystem including a transmitter antenna subsystem and a power signal tuner module. The tuner module is configured to adjust the transmission mode ratio by adjusting a power signal supplied from the tuner module to the transmitter antenna subsystem. The system further includes a receiver subsystem including a receiver antenna subsystem configured to receive electrical power from the transmitter antenna subsystem at the transmit mode ratio.WO 2022 / 058790, describes another such system, in which the transmitter subsystem comprises a control unit and a sensor. The controller is configured to receive sensor information from the sensor and automatically provide a tuning instruction to the tuner module based on the sensor information. The tuner module is configured to adjust the phase difference between the current and the voltage of the power signal provided to the transmission antenna subsystem according to the tuning instruction.An object of the invention is to provide an improved device for wireless electrical power and / or communication transmission for an electric machine, in particular for a separately excited synchronous machine.A further object of the invention is to provide an improved electric machine, in particular a separately excited synchronous machine, having such a device.A further object of the invention is to provide an improved drive system for an electrically operable vehicle having an electric machine with such a device and an inverter.The aforementioned objects are achieved with the features of the independent claims.Advantageous embodiments and advantages of the invention are evident from the further claims, the description and the drawing.According to one aspect of the invention, a device for wireless electrical power and / or communication transmission for an electric machine, in particular for a separately excited synchronous machine, is proposed, at least comprising a first transmission unit which is arranged in a stationary manner spatially adjacent to the electric machine, in particular on a housing of the electric machine, and a second transmission unit which is arranged on a rotating part, in particular a shaft, of the electric machine. The first transmission unit and the second transmission unit are designed for capacitive and inductive coupling by means of electrical and / or magnetic and / or coupled electromagnetic fields, wherein the first transmission unit and the second transmission unit are resonantly tuned to one another. During operation of the electric machine, the first transmission unit and the second transmission unit are configured selectively as a transmission unit or as a reception unit. In this case, for operation of the electric machine, at least second of all, the first transmission unit is configured as a transmission unit and the second transmission unit is configured as a reception unit for transmitting electrical power from the first transmission unit to the second transmission unit.With the proposed device, a transmission of electrical power to an electrical machine can take place. In this case, further functions are advantageously made possible since the device is substantially more variable than a purely inductive energy transmission system. Advantageously, the transmitter and receiver are constructed in the same way here and allow the transmission and also communication in both directions. As a result, a role of the two transmission units can be exchanged. Both energy transmission and, in particular, communication can proceed bidirectionally. Such a device can be used advantageously in an electric machine and above all in its operation and control.In addition, the energy transmission is directed, which also influences the arrangement of transmitter and receiver.Advantageously, the transmission of electrical power to the electric machine can thus be carried out with lower losses than in the case of a purely inductive concept.Advantageously, externally excited synchronous machines can be used in this way for electric drives of vehicles. This makes it possible to use permanent magnets in electric drives, which means both a cost advantage and protection of global reserves on rare earths, which are required for the production of permanent magnets. The energy for producing the permanent magnets can also be saved, which makes such drives without permanent magnets more durable. Dispensing with permanent magnets and thus depending on the type of production can also be advantageous in tensed geopolitical situations.Since no pulverized coal is produced during wireless power transmission without the use of brushes, an otherwise necessary encapsulation of the motor can be omitted. Since no carbon brushes are used, there is also no limitation of the service life due to possible exchange intervals for carbon brushes.Since the wireless electrical power transmission with the proposed device is not based on a purely inductive concept, no additional heat loss is also produced due to large-sized electrical coils, since these are not exclusively used for power transmission.According to an advantageous embodiment of the device, the first and the second transmission unit can be designed for the bidirectional transmission of electrical power and / or communication signals. In this way, measured values from the electric machine can be used to perform an open-loop and / or closed-loop control of the electric machine. Monitoring of the electric machine is also advantageously possible.Alternatively or additionally, the first and second transmission units can be designed for spatially directed transmission of electrical power. Thus, the transmitted electrical power can be transmitted in a focused manner, for example via antenna elements, as a result of which fewer losses arise.According to an advantageous embodiment of the device, the first transmission unit can be arranged axially or radially with respect to the shaft of the electric machine. Alternatively or additionally, the second transmission unit can be integrated into the shaft of the electric machine. In particular, the second transmission unit can be integrated within the shaft centrally or decentrally on at least one side within the shaft. This makes it possible to realize a short transmission path from the first transmission unit to the second transmission unit. Advantageously, a transmission of electrical power over small distances can thus be carried out with fewer losses.According to an advantageous configuration of the device, the first transmission unit can be designed for transmitting at least one electrical voltage and at least one electrical current for driving the rotor of the electric machine from an electrical inverter to the second transmission unit. Furthermore, the second transmission unit may be configured to forward the at least one electrical voltage and the at least one electrical current to the rotor of the electric machine. As a result, the electric machine, in particular a separately excited synchronous machine, can be advantageously controlled and operated.According to an advantageous embodiment of the apparatus, the first and the second transmission unit can be configured alternately in time as a transmission unit and as a reception unit. Thus, with intermittent operation, for example, electrical power can be transmitted back in one direction and measured values in the opposite direction.According to an advantageous embodiment of the device, at least one first and one second transmission unit can be arranged in the shaft of the electric machine. In an alternative embodiment, it is also possible for two transmission units to be arranged in the shaft, such that, for example, electrical power is transmitted permanently via the first transmission unit and measured values are transmitted permanently back to the inverter in the opposite direction via the second transmission unit.According to an advantageous embodiment of the device, the first transmission unit arranged in the shaft can be designed for capturing measured values of the electric machine, in particular measured values of an electric voltage and / or of an electric current of the electric machine, and for transmitting the measured values to a second transmission unit arranged in a stationary manner. In this way, measured values from the electric machine can be used to perform an open-loop and / or closed-loop control of the electric machine. Monitoring of the electric machine is also advantageously possible.According to an advantageous embodiment of the device, at least one second transmission unit can be arranged in a stationary manner, which is designed to forward the measured values to the inverter. The inverter can advantageously process the measurement values further and use them for controlling and / or regulating the electric machine.According to one aspect of the invention, an electric machine, in particular a separately excited synchronous machine, having a device for wireless electrical power and / or communication transmission is proposed.With a device as described above, a transmission of electrical power to the proposed electrical machine can take place. In this case, further functions are advantageously made possible in the case of the proposed electric machine, since the device is substantially more variable than a purely inductive energy transmission system. Advantageously, the transmitter and receiver are constructed in the same way here and allow the transmission and also communication in both directions. As a result, a role of the two transmission units can be exchanged. Both energy transmission and, in particular, communication can proceed bidirectionally. Such an electric machine can be advantageously controlled and operated.In addition, the energy transmission of the device is directed, which also influences the arrangement of transmitter and receiver.Advantageously, the transmission of electrical power to the electric machine can thus be carried out with lower losses than in the case of a purely inductive concept.Advantageously, externally excited synchronous machines can be used in this way for electric drives of vehicles. This makes it possible to use permanent magnets in electric drives, which means both a cost advantage and protection of global reserves on rare earths, which are required for the production of permanent magnets. The energy for producing the permanent magnets can also be saved, which makes such drives without permanent magnets more durable. Dispensing with permanent magnets and thus depending on the type of production can also be advantageous in tensed geopolitical situations.Since no pulverized coal is produced during wireless power transmission without the use of brushes, an otherwise necessary encapsulation of the motor can be omitted. Since no carbon brushes are used, there is also no limitation of the service life due to possible exchange intervals for carbon brushes.Since the wireless electrical power transmission in the case of the proposed electrical machine is not based on a purely inductive concept, no additional heat loss is also produced by large-dimensioned electrical coils, since these are not exclusively used for power transmission.According to one aspect of the invention, a drive system for an electrically operable vehicle is proposed, at least comprising an electric machine, in particular a separately excited synchronous machine, having a device for wireless electrical power and / or communication transmission, and an inverter for actuating the electric machine.Advantageously, such a drive system represents a very efficient way of driving an electrically operable vehicle. The electrical power and / or communication transmission between inverter and electric machine takes place in a very efficient manner. Such a drive system is also low-maintenance by the wireless transmission. If a separately excited synchronous machine is used, permanent magnets can advantageously be dispensed with, which brings with it the advantages already described.Further advantages are evident from the following description of the drawings. The drawings illustrate an embodiment of the invention. The drawings, specification and claims contain numerous features in combination. The skilled person will expediently also consider the features individually and summarize them to form meaningful further combinations.The following are shown: FIG. 1 shows a schematic illustration of a drive system according to the invention having an electric machine, in particular a separately excited synchronous machine, which is actuated by an inverter via a device for wireless electrical power and / or communication transmission to the electric machine; FIG. 2 shows a schematic illustration of such a drive system according to a further exemplary embodiment of the invention; FIG. 3 shows a schematic illustration of such a drive system according to a further exemplary embodiment of the invention; and FIG. 4 shows a schematic illustration of such a drive system according to a further exemplary embodiment of the invention.In the figures, identical or similar components are denoted by identical reference numerals. The figures merely show examples and should not be understood as limiting.FIG. 1 shows a schematic illustration of a drive system 200 according to the invention having an electric machine 50, in particular a separately excited synchronous machine, which is actuated by an inverter 30 via a device 100 for wireless electrical power and / or communication transmission to the electric machine 50.The electric machine 50 comprises, as rotating parts 54, the shaft 56 with the rotor 58, which has electric coils. Shaft 56 and rotor 58 are disposed in a housing 52. The stator of the electric machine 50 is not shown for the sake of clarity. The rotation of the shaft 56 with the rotor 58 is indicated as an arrow.The inverter 30 comprises a stator controller 32, a rotor controller 34, and a measured value processing 38. In this case, electrical power is transmitted from the rotor controller 34 to the device 100 via electrical voltage values 66 and electrical current values 68. In addition, measured values 36 of the electric machine 50 are transmitted from the device 100 to the measured value processing 38.The device 100 comprises a first transmission unit 10, which is arranged in a stationary manner spatially adjacent to the electric machine 50, in particular on the housing 52 of the electric machine 50, and a second transmission unit 20, which is arranged on a rotating part 54, in particular the shaft 56, of the electric machine 50. The second transmission unit 20 is thus not stationary, but rotates at the engine speed. The first transmission unit 10 is connected in a stationary manner to the housing 52 of the electric machine 50.The first transmission unit 10 and the second transmission unit 20 are capacitively and inductively coupled by means of electrical and / or magnetic and / or coupled electromagnetic fields. In this case, the first transmission unit 10 and the second transmission unit 20 are resonantly coordinated with one another.The first transmission unit 10 and the second transmission unit 20 can be configured selectively as a transmission unit 14 or as a reception unit 24 during operation of the electric machine 50.For an operation of the electric machine 50, the first transmission unit 10 is configured at least two times as a transmission unit 14 and the second transmission unit 20 as a reception unit 24 for transmitting electrical power from the first transmission unit 10 to the second transmission unit 20.The first and the second transmission unit 10, 20 are designed for the bidirectional transmission of electrical power and / or communication signals. The first transmission unit 10 is electrically coupled to the rotor controller 34 and the measurement value processing 38 of the inverter 30.The transmission of electrical power via the first and second transmission units 10, 20 takes place in a spatially directed manner. For this purpose, in the exemplary embodiment shown in FIG. 1, the first transmission unit 10 is arranged axially with respect to the shaft 56 of the electric machine 50. The second transmission unit 20 is integrated into the shaft 56 of the electric machine 50. For this purpose, the second transmission unit 20 can expediently be integrated centrally within the shaft 56.In this way, the first transmission unit 10 transmits the electric voltage 66 and the electric current 68 for driving the rotor 58 of the electric machine 50 from the electric inverter 30 to the second transmission unit 20. The coils of the rotors 58 are supplied with setpoint voltage 66 and setpoint current 68 via power lines 60 or coil direct contacting in order to ensure operation of the electric machine 50.Advantageously, in the exemplary embodiment shown in FIG. 1, the first and the second transmission unit 10, 20 can be configured alternately in time as transmission unit 14 and as reception unit 24. Thus, the second transmission unit 20 configured as a transmission unit 14 can transmit measured values of the electric machine 50, which are combined in a measured value detection unit 70, to the first transmission unit 10 configured as a reception unit 24, from where the measured values 36 are conducted to the measured value processing 38 of the inverter 30. Measured values 36 can originate from a voltage measurement 62 and / or a current measurement 64 of the electrical voltages 66 and currents 68 of the electrical machine 50. In addition, temperature values, in particular a winding temperature of a rotor coil, of a temperature sensor 72 can be sent to the inverter 30 via the device 100, for example.FIG. 2 shows a drive system 200 having an electric machine 50 and an inverter 30 having a device 100 according to a further exemplary embodiment of the invention.In this exemplary embodiment, the first transmission unit 10 is arranged radially with respect to the second transmission unit 20 next to the shaft 56. The configurations of the first and second transmission units 10, 20 intermittently as transmission unit 14 and as reception unit 24 are in this case as in the exemplary embodiment in FIG. 1. Due to the radial arrangement of the first transmission unit 10 radially with respect to the second transmission unit 20, a narrow distance between the first and second transmission units 10, 20 can be maintained, such that the operation of the electric machine 50 via the apparatus 100 is ensured.FIG. 3 shows a drive system 200 according to a further exemplary embodiment of the invention.Both a first transmission unit 10 and a second transmission unit 22 are arranged in a stationary manner on the housing 52 of the electric machine 50. The first transmission unit 10 is electrically coupled to the rotor controller 34 and is configured as a transmission unit 14. The second transmission unit 22 is electrically coupled to the measured value processing unit 38 and is configured as a receiving unit 24. The two transmission units 10, 22 are arranged axially to the shaft 56.A first and a second transmission unit 12, 20 are arranged in the shaft 56 of the electric machine 50. The second transmission unit 20 is configured as a receiving unit 24 and serves for the electrical power transmission with electrical voltage 66 and electrical current 68 for operating the electrical machine 50. the first transmission unit 12 is configured as a transmitting unit 14 and serves for the transmission of measured values 36 from the electrical machine 50, in particular measured values 36 of an electrical voltage 66 and / or of an electrical current 68 of the electrical machine 50, via the stationary second transmission unit 22 to the inverter 30.The two transmission units 12, 20 in the shaft 56 can also be integrated decentrally on sides within the shaft 56.In the exemplary embodiment illustrated in FIG. 3, the transmission units 10, 12, 20, 22 do not need to be reconfigured during the operation of the electric machine 50. The configuration once set may be maintained for operation of the electric machine. Electrical power such as voltage 66 and current 68 and measured values 36 are advantageously transmitted via separate transmission units 10, 12, 20, 22. Higher interference safety can thus be ensured in an advantageous manner.FIG. 4 shows a corresponding drive system 200 according to a further exemplary embodiment of the invention.In this case, the first and second stationary transmission units 10, 22 are respectively arranged on the housing 52 of the electric machine 50 radially on both sides of the shaft 56. The first and second transmission units 12, 20 integrated in the shaft 56 are arranged on the side of the shaft 56, as in the exemplary embodiment shown in FIG. 3.The first and second transmission units 10, 12, 20, 22 are configured as in the embodiment shown in FIG. 3.Since the shaft 56 of the electric machine 50 rotates during operation, a close distance is obtained sufficiently often during operation of the electric machine 50 between the first and second stationary transmission units 10, 22 and the first and second transmission units 12, 20 integrated in the shaft 56, so that reliable wireless transmission of electrical power in the form of voltage 66 and current 68, and of measurement values 36 of the electric machine 50, can take place.List of reference characters10 first transmission unit 12 first transmission unit 14 transmission unit 20 second transmission unit 22 second transmission unit 24 reception unit 30 inverter 32 stator controller 34 rotor controller 36 measurement value 38 measurement value processing 50 electric machine 52 housing 54 rotating part 56 shaft 58 rotor 60 power line 62 voltage measurement 64 current measurement 66 electric voltage 68 electric current 70 measurement value detection 72 temperature sensor 100 device 200 drive systemReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2012 010 752 A1

[0003] WO 2020 / 185877

[0004] WO 2022 / 058790

[0005]

Claims

Device (100) for wireless electrical power and / or communication transmission for an electric machine (50), in particular for a separately excited synchronous machine, at least comprising - a first transmission unit (10, 12) which is arranged in a stationary manner spatially adjacent to the electric machine (50), in particular on a housing (52) of the electric machine (50), and - a second transmission unit (20, 22) which is arranged on a rotating part (54), in particular a shaft (56), of the electric machine (50), wherein first transmission unit (10, 12) and second transmission unit (20, 22) are configured for capacitive and inductive coupling by means of electrical and / or magnetic and / or coupled electromagnetic fields, wherein first transmission unit (10, 12) and second transmission unit (20, 22) are resonantly tuned to one another, wherein first transmission unit (10, 12) and second transmission unit (20, 22) are resonantly tuned to one another, wherein first transmission unit (10, 12) and second transmission unit (20, 12), The transmission unit (10, 12) is configured as a transmission unit (14) or as a reception unit (24), optionally, during operation of the electric machine (50), wherein, for operation of the electric machine (50), the first transmission unit (10, 12) is configured as a transmission unit (14) and the second transmission unit (20, 22) is configured as a reception unit (24) for transmitting electrical power from the first transmission unit (10, 12) to the second transmission unit (20, 22).Device according to Claim 1, wherein the first and the second transmission unit (10, 12, 20, 22) are designed for the bidirectional transmission of electrical power and / or communication signals, and / or wherein the first and the second transmission unit (10, 12, 20, 22) are designed for the spatially directed transmission of electrical power.Device according to claim 1 or 2, wherein the first transmission unit (10, 12) is arranged axially or radially to the shaft (56) of the electric machine (50), and / or wherein the second transmission unit (20, 22) is integrated into the shaft (56) of the electric machine (50), in particular wherein the second transmission unit (20, 22) is integrated within the shaft (56) centrally or decentrally on at least one side within the shaft (56).Device according to one of the preceding claims, wherein the first transmission unit (10, 12) is designed to transmit at least one electrical voltage (66) and at least one electrical current (68) for driving the rotor (58) of the electrical machine (50) from an electrical inverter (30) to the second transmission unit (20, 22), and wherein the second transmission unit (20, 22) is designed to forward the at least one electrical voltage (66) and the at least one electrical current (68) to coils of the rotor (58) of the electrical machine (50).The device according to any one of the preceding claims, wherein the first and the second transmission unit (10, 12, 20, 22) are configured alternately in time as a transmission unit (14) and as a reception unit (24).Device according to one of the preceding claims, wherein at least one first and one second transmission unit (10, 12, 20, 22) are arranged in the shaft (56) of the electric machine (50).Device according to Claim 6, wherein the first transmission unit (10, 12) arranged in the shaft (56) is designed for recording measurement values (36) of the electric machine (50), in particular measurement values (36) of an electrical voltage (66) and / or of an electrical current (68) of the electric machine (50), and for transmitting the measurement values (36) to a second transmission unit (20, 22) arranged in a stationary manner.Device according to one of Claims 5 to 7, wherein at least one second transmission unit (20, 22) is arranged in a stationary manner, which is designed for forwarding the measured values (36) to the inverter (30).Electric machine (50), in particular a separately excited synchronous machine, having a device (100) for wireless electrical power and / or communication transmission according to one of the preceding claims.Drive system (200) for an electrically operable vehicle, at least comprising an electric machine (50) according to Claim 9, in particular a separately excited synchronous machine, having a device (100) for wireless electrical power and / or communication transmission according to one of Claims 1 to 8, and an inverter (30) for actuating the electric machine (50).

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