Converter motor and simulation program product

Abstract

The invention relates to a converter motor (10) which comprises a housing (22), and a motor (20) with a stator (24) and a rotor (26) on a rotor shaft (23). The rotor shaft (23) is rotatably mounted on two bearings (28). The converter motor (10) also comprises a converter (30), wherein the stator (24), the rotor (26) and the converter (30) are accommodated in the housing (22). According to the invention, the converter (30) is arranged with the rotor (26) and the stator (24) in a common motor chamber (25) in the housing (22) between the bearings (28). The invention also relates to a simulation program product (60) of the converter motor (10), which can be in the form of a digital twin (65).

Description

[0001] Description

[0002] Inverter motor and simulation program product

[0003] The invention relates to an inverter motor and a simulation program product for simulating the operating behavior of such an inverter motor.

[0004] Patent application DE 10 2005 032 964 A1 discloses a converter motor in which the converter is divided into several printed circuit boards that are articulated together. In the assembled state, the printed circuit boards are arranged in the housing of the converter motor.

[0005] Electric motors are used in significant quantities in various technical applications. Increased energy efficiency, durability, cost-effectiveness, and ease of maintenance are desired for such electric motors, particularly for inverter motors. Likewise, improved predictability of maintenance and repair procedures is sought. The invention aims to provide an inverter motor that offers an improvement in at least one of these aspects. The invention also aims to provide a means of improving the predictability of maintenance and repair procedures and to provide a direct electrical connection between the inverter and the stator winding.

[0006] The problem is solved by a converter motor according to the invention. The converter motor comprises a housing in which a motor is mounted, the motor comprising a stator and a rotor as so-called active components. The rotor is mounted on a rotor shaft, which is rotatably arranged on two bearings that are also part of the converter motor. Furthermore, a converter is part of the converter motor and is also mounted in the housing. According to the invention, the converter, the rotor, and the stator are arranged in a common motor compartment within the housing. The converter is mounted between the bearings in which the rotor shaft is rotatably mounted. The converter is located between the bearings along an axial direction that extends essentially along the rotor shaft. The bearings can each be mounted in a bearing shield, which forms the end face of the housing.The common motor space is understood to mean, in particular, a continuous, clear space in which components of the inverter and components of the stator and / or rotor are essentially directly opposite each other, especially when viewed in the axial direction.

[0007] This minimizes the spatial distance between the inverter and the rotor and stator. The inverter is thus connected to the motor's terminals, such as the stator windings, via contacts within the inverter motor. These contacts can be direct connections, eliminating the need for additional cables. Furthermore, an electrical connection between the inverter and the motor's terminals can be located within the inverter motor's housing. This ensures connection to the grid's power supply. The electrical connection between the inverter and the motor can be, for example, a plug connector.This creates an electrical connection with defined properties between the inverter and the motor, allowing for precise and coordinated control of both, thus maximizing their technical potential. Furthermore, the direct contact between the inverter, particularly its intermediate circuit, and the motor results in reduced impedance.

[0008] The impedance between the stator and the DC link of the inverter is lower than the impedance between the stator and the grounding system in which the drive system is embedded. This minimizes or even prevents ground currents flowing via the path stator – bearings – drive shaft – load / application. Currents that can be caused by parasitic capacitances in the motor and flow through the bearings are thus reduced or even prevented. Consequently, bearing degradation, for example, due to micro-welding between rolling elements and raceways in the bearing rings, is reduced. Therefore, placing the inverter between the bearings serves to reduce bearing degradation in the inverter motor.

[0009] During operation of the inverter motor, various losses occur in the inverter and the motor. The higher the switching frequency of the inverter, i.e., the semiconductor switch within its inverter, the lower the motor losses. Simultaneously, inverter losses increase with higher switching frequencies. Correspondingly, motor losses increase with lower switching frequencies. Similarly, inverter losses decrease with lower switching frequencies. Because the components of the inverter motor—as well as the electrical connections—are precisely defined, the inverter motor can be controlled accurately and in a coordinated manner, for example, to utilize the thermal capacity of the inverter and / or the motor. The placement of the inverter between the bearings therefore also serves to increase the utilization of the thermal capacities of the inverter and / or motor.In this case, the motor can have a higher thermal capacity than the inverter.

[0010] Furthermore, voltage spikes at the motor terminals caused by pulsed inverter operation are reduced by the defined and low-impedance electrical connection between the inverter and the motor; voltage spikes due to cable reflections do not occur. Consequently, electrical stresses on the motor's insulation, particularly slot and phase insulation, are reduced. Positioning the inverter between the bearings thus contributes to a reduction in the electrical stress on the motor's insulation.

[0011] The fact that at least one of the bearings can be mounted on a bearing shield and is accessible from the outside simplifies access. This also improves the ease of maintenance of the inverter motor.

[0012] In one embodiment of the claimed inverter motor, the space between the inverter and the rotor is essentially free of partitions. Such a partition can be integrally formed with the housing. This minimizes the distance between the inverter and the rotor, and thus also between the inverter and the stator. This further reduces the impedance between the inverter and the motor. The impedance between the stator and the DC link is therefore essentially known and definable, which in turn simplifies the modeling of the associated electrical operating behavior. Consequently, the claimed inverter motor, and in particular its behavior under the influence of electrical disturbances, can be easily modeled and calculated. Additional wiring between the inverter and the motor, as well as its modeling, is unnecessary.This in turn allows for a simplified and at the same time more efficient parameterization of the inverter motor under use.

[0013] In another embodiment of the claimed inverter motor, it has at least one temperature sensor arranged in the housing and configured to detect the operating temperature of the inverter, the stator, and / or the rotor. Due to the design of the claimed inverter motor, thermally consistent conditions prevail within the housing, which can be measured reliably and precisely. Based on corresponding measured values ​​from the at least one temperature sensor, i.e., temperature readings, the claimed inverter motor can be parameterized and / or controlled as required. Accordingly, the claimed inverter motor can be parameterized to allow for greater utilization of the components used within it, such as semiconductor switches in the inverter. This results in a more efficient use of the inverter motor's performance potential.In a preferred embodiment of the claimed inverter motor, both the inverter and the motor, i.e., the rotor and / or the stator, are each equipped with a temperature sensor. Alternatively or additionally, a thermal model of the inverter motor can be provided, which is configured to determine the temperature at the motor, i.e., the rotor and / or stator, or at the inverter, based on measured values ​​from the at least one temperature sensor. Furthermore, alternatively or additionally, the claimed inverter motor can be equipped with a control unit configured to specify a switching frequency of the inverter depending on measured values ​​from the at least one temperature sensor. This could, for example, be a switching frequency of semiconductor switches in the inverter of the converter. The lower the switching frequency of the converter, the lower the resulting converter losses.The higher the switching frequency of the inverter, the lower the resulting motor losses. Accordingly, the technical potential of the inverter motor can be utilized more accurately, reliably, and thus more effectively overall, thanks to the inclusion of at least one temperature sensor. The control unit can be equipped with a computer program that, when executed, implements a corresponding operating procedure for the inverter motor.

[0014] Furthermore, the control unit of the inverter motor in question can be configured to specify the switching frequency of the inverter, i.e., of the semiconductor switches of the inverter's component, for the psychoacoustic optimization of the motor's noise emission. Humans perceive noise emissions as tolerable or intolerable to varying degrees depending on different acoustic parameters. An executable algorithm can be stored on the control unit for this purpose, enabling the psychoacoustic optimization of noise emissions occurring during operation of the inverter motor. The algorithm can, for example, be a selection algorithm that chooses a suitable set of parameters, particularly for the switching frequency, from a table or characteristic map that defines the current operating state.Alternatively or additionally, the algorithm can be designed as a corresponding artificial intelligence. The algorithm can be configured to determine the expected noise emission of the inverter as a function of the switching frequency. Due to the design of the inverter motor, its electrical behavior, and consequently its acoustic operating behavior, can be precisely modeled. The noise emission behavior of the inverter motor can thus be specifically adapted to the health and / or comfort needs of people in its vicinity. The control unit can also be equipped with a correspondingly designed computer program for this purpose. This computer program can further be configured to prioritize psychoacoustic optimization based on other operating conditions of the inverter motor, such as the existing thermal load.

[0015] Alternatively or additionally, the control unit of the claimed inverter motor can be configured to specify the switching frequency of the inverter, i.e., the semiconductor switches in the inverter, in order to minimize discharge activity, in particular partial discharge activity.

[0016] Similarly, the control unit can be configured to control a braking process on the inverter motor, thus minimizing any increase in the DC link voltage. The control unit can be equipped with a suitably designed computer program for this purpose. By minimizing discharge activity, stress on insulation, particularly on motor windings, can be reduced. Setting the inverter's switching frequency can be prioritized based on an existing or anticipated thermal load on the inverter and / or psychoacoustic optimization of the inverter motor. Furthermore, the objectives of a predefined thermal load, psychoacoustic optimization, and / or minimizing discharge activity can be pursued with a predefined weighting.Accordingly, the control unit and the associated computer program can be configured to execute appropriate optimization algorithms with a predefined relative weighting. This allows for the achievement of an overall optimum for the operation of the inverter motor, which incorporates at least two of the specified optimization goals. The computer program can incorporate suitable artificial intelligence for this purpose.

[0017] Furthermore, the control unit can be configured to specify the switching frequency of the inverter to define a distribution of power losses at the motor. The higher the switching frequency of the inverter, i.e., the semiconductor switches located within it, the higher the losses occurring in the inverter.

[0018] Simultaneously, the losses occurring in the motor are lower the higher the switching frequency at which the inverter is operated. Conversely, the losses occurring in the inverter are lower the lower the switching frequency at which the inverter is operated. Correspondingly, the losses occurring in the motor are higher the lower the switching frequency at which the inverter, i.e., the semiconductor switches within the inverter, are operated.

[0019] The generation of losses, i.e., the occurrence of power losses, in the motor and the inverter is accompanied by the generation of waste heat. By specifying the switching frequency of the inverter, it is possible to determine the extent of waste heat generated in the motor or inverter during operation. Depending on the temperature of a corresponding component in the motor or inverter and a corresponding limit value for intended operation, the generation of waste heat can be adjusted. Such a limit value can be specified as a static value, defined by a table depending on another operating condition variable, by an algorithm, and / or by artificial intelligence. Accordingly, the thermal potential of the inverter motor, and thus its power potential, can be utilized more effectively.For this purpose, the control unit can be equipped with a suitably designed computer program product.

[0020] In another embodiment, the motor can be equipped with a measuring device designed to detect an electrical quantity. The measuring device can be a voltage measuring device, in particular a capacitive ring-wave arrangement. Alternatively or additionally, a current and / or voltage measuring device can be provided at the motor's terminals. The measuring device can be equipped with an evaluation unit designed to detect discharge activity at the motor based on the electrical quantity detectable by the measuring device. Discharge activity in this context also includes partial discharges that stress the motor's insulation.The claimed inverter motor can be operated with reduced discharge activity by detecting the discharge activity within the motor winding and determining the electrical bearing load through the shaft-ring arrangement, and by adjusting operating parameters such as speed, load, and switching frequency accordingly. In conjunction with the measuring device, this allows for an increased, technically usable service life of the insulation.

[0021] Furthermore, a vibration sensor can be arranged on at least one of the bearings, particularly on a bearing located on the non-drive side of the motor. Based on measurements acquired by the vibration sensor, the wear condition of the corresponding bearing can be determined. The vibration sensor can be connected to the evaluation unit of the inverter motor. For this purpose, the evaluation unit can be equipped with a computer program designed to receive and process measurements from the vibration sensor and thereby determine the degree of bearing degradation. Furthermore, by detecting vibrations, such as vibration velocity, critical vibration states can be identified. Consequently, components of the inverter motor can be protected from impermissible vibration stresses. This also includes the detection of application-related vibration loads.

[0022] In another embodiment, the evaluation unit can be configured to determine the degradation level of at least one of the bearings based on the measurement signals from the voltage measuring device and the vibration sensor. Alternatively or additionally, the evaluation unit can be configured to determine the expected remaining service life of at least one bearing. When using relubricated bearings, relubrication intervals can be adjusted as needed. For this purpose, the evaluation unit can be equipped with a correspondingly designed computer program. The evaluation unit can be integrated as part of the control unit of the inverter motor, i.e., be a module of it, or vice versa. Accordingly, the inverter motor in question is suitable for maximizing the extended service life of its bearings while reducing the risk of failure.Alternatively or additionally, maintenance work can be planned according to demand, thereby minimizing unplanned downtime.

[0023] Furthermore, the evaluation unit can be configured to predict a technically usable remaining service life of the insulation on the rotor and / or stator of the motor, for example, winding insulation. For this purpose, measurement signals from the current and voltage measuring device can be used. Additionally, operating programs from the control unit, which define the future operation of the inverter motor, can be utilized. Likewise, historical operating data from the inverter can be used to extrapolate, for example, future operating or load profiles of the inverter motor. Because the insulation materials used are known and defined, an exact service life model for the insulation can be provided. This model allows the service life-reducing effects of partial discharges on the insulation to be precisely simulated and determined.

[0024] The underlying problem is also solved by an operating method according to the invention for a converter motor. The converter motor comprises a converter, a stator, and a rotor, which are arranged in a housing. The operating method includes a first step in which the converter motor is provided in an active operating state. In the active operating state, the converter is connected to a power supply, and a variable electrical drive power is provided to the motor by operating the converter. Furthermore, in the first step, at least one temperature value is provided that corresponds to a temperature at the converter, the stator, and / or the rotor. For this purpose, the converter motor can be equipped with at least one temperature sensor that detects the temperature at the corresponding component.Alternatively or additionally, at least one temperature measurement can be provided by a temperature model of the inverter motor. This temperature model can be provided, for example, by a simulation software product, in particular by a digital twin of the inverter motor.

[0025] The operating procedure also includes a second step in which the thermal load state of the inverter is determined. Likewise, the thermal load state of the stator and / or rotor is determined. This thermal load state can represent a relationship between the temperature value provided in the first step and the maximum tolerable temperature of the corresponding component. For example, the thermal load state can indicate how far the thermal capacity of the corresponding component has been utilized. Correspondingly, in the second step, the thermal load state of the rotor and / or stator is determined.

[0026] In a third step of the operating method according to the invention, at least one of the thermal stress states determined in the second step is compared with a corresponding limit value. This limit value can correspond to a temperature below the maximum tolerable temperature of the respective component. Furthermore, a fourth step is part of the claimed operating method, in which the switching frequency of the inverter is changed if the at least one thermal stress state in the third step exceeds the corresponding limit value. This indicates that the thermal stress state determined in the second step is contrary to the intended use and should be avoided, or that countermeasures are necessary. By changing the switching frequency of the inverter, i.e., of semiconductor switches in its inverter, the occurrence of heat losses in the inverter motor can be influenced.In particular, increasing the switching frequency can reduce heat losses in the motor. However, this also increases heat losses in the inverter. Conversely, reducing the switching frequency has the opposite effect.

[0027] The claimed operating method is suitable for predictably distributing the occurrence of heat losses, and thus of thermal stress conditions in the components of the inverter motor, between the motor and the inverter.

[0028] This allows the thermal potential of the inverter motor to be specifically utilized. In one embodiment of the claimed operating method, the thermal load state of the inverter, stator, and / or rotor is determined in the second step. The thermal load state is determined based on a temperature measurement. The first temperature measurement is acquired using a temperature sensor located in the inverter motor. Alternatively or additionally, existing thermal load states can be acquired for several components of the inverter motor, each based on a temperature measurement from a temperature sensor assigned to the respective component. The use of temperature sensors allows for the rapid and precise provision of corresponding temperature measurements.Alternatively or additionally, the existing thermal load state of at least one component of the inverter motor can be determined using a temperature model. The use of a temperature model allows for a reduced number of temperature sensors. Overall, the claimed operating method enables a quick and targeted response to a real-world operating situation with regard to thermal conditions. The more precise the temperature sensor used, i.e., the better its thermal connection, the more effectively the thermal potential of the inverter motor can be utilized.

[0029] Furthermore, in the claimed operating method, a future thermal load state of the converter, stator, or rotor can be determined in the second step. This future thermal load state is determined based on a planned operating parameter of the converter motor. The planned operating parameter can be provided, for example, by a computer program that controls the converter motor. For this purpose, pattern recognition can be performed during the active operation of the converter motor, allowing the planned operating parameter to be predicted. Accordingly, in the second step, an impending or expected thermal load state is determined, which will occur if the active operating state of the converter motor continues as planned or predicted.The claimed operating method is suitable for proactively avoiding unintended thermal stress conditions. For example, during cyclic operation, interruptions can be avoided, and the cyclic operation can instead be carried out at reduced power. The inverter motor can be equipped with artificial intelligence trained to specify switching frequencies for thermally optimized operation.

[0030] Furthermore, the claimed operating method can include a fifth step in which a psychoacoustic load level is determined for the current active operating state. A computer program used to execute the operating method can be equipped with a computational model designed to predict the acoustic emissions of the inverter motor in predefined operating situations. In a sixth step, a psychoacoustic optimization algorithm is performed. This algorithm can be configured to identify active operating states in which the psychoacoustic load level is lower than in the current active operating state by varying operating parameters. Finally, in the sixth step, the inverter's control behavior is modified based on the psychoacoustic optimization algorithm.In the sixth step, this results in a changed active operating state. The psychoacoustic optimization can be prioritized depending on the current or future thermal load. For example, psychoacoustic optimization can be prioritized if the inverter has sufficient thermal reserves. Conversely, psychoacoustic optimization can be postponed if a critical thermal load is present or imminent. In another embodiment of the claimed operating method, the inverter motor on which it is performed can be designed according to one of the embodiments described above. Such an inverter motor is particularly well-suited to carrying out the claimed operating method due to its design.In particular, the low-impedance electrical connection between the inverter and the motor, and the defined combination of inverter and motor, enable targeted determination of thermal load conditions, and allow for influencing an existing or impending thermal load condition by changing the switching frequency of the inverter. The features of the claimed inverter motor are transferable individually or in combination to the claimed operating method and vice versa.

[0031] Furthermore, the problem outlined above is solved by a computer program product according to the invention. The computer program product is configured to determine and output at least one control command for a component of an inverter motor. The computer program product can also be configured to receive and process measured values, for example, from a temperature sensor. The computer program product can have appropriately suitable data interfaces for outputting control commands and / or receiving measured values. Furthermore, the computer program product can be stored on non-volatile memory and comprise executable code. According to the invention, the computer program product is configured to carry out at least one embodiment of the operating method outlined above. Alternatively or additionally, the computer program product can be configured to operate an inverter motor according to one of the embodiments described above.The features of the operating method and the inverter motor are accordingly transferable to the claimed computer program product. The underlying problem is also solved by a simulation program product according to the invention. The simulation program product comprises instructions that cause a computer to simulate the operating behavior of an inverter motor when the instructions are executed. The simulation program product can be stored on non-volatile memory, for example, a hard drive, flash memory, or an optical storage medium. According to the invention, the inverter motor, whose operating behavior can be simulated with the simulation program product, is designed according to one of the embodiments outlined above. The features of the claimed inverter motor and their technical advantages are readily transferable to the claimed simulation program product.

[0032] The simulation software product can be trained to perform a simulation procedure that includes the following steps:

[0033] In a first step, a plurality of data points is provided, which at least partially represent the inverter motor to be simulated. These data points can be configured to replicate the structure and / or operation of the inverter motor. For example, the data points can also constitute a computational model of the inverter motor. Essentially, the data points form a virtual representation of the inverter motor. In a second step, an operating parameter is specified that characterizes the operating behavior to be simulated. This operating parameter can include, for example, the power output of the inverter motor, its ambient temperature, and / or the electrical behavior of the power grid supplying the inverter motor.Furthermore, the operating parameter can be a switching frequency of the inverter, i.e., of at least one semiconductor switch located within it. Essentially, the operating condition of the inverter motor to be simulated can be described by this at least one operating parameter.

[0034] In a subsequent third step, at least one performance parameter is determined based on the majority of data points and at least one operating parameter. The performance parameter could, for example, be a measurement signal generated by the voltage measuring device and / or the vibration sensor. Alternatively or additionally, the performance parameter could also be the expected remaining service life of insulation on the rotor and / or stator, or the degradation state of a bearing. Furthermore, alternatively or additionally, the performance parameter could be heat losses occurring in a component of the inverter motor and / or the current efficiency of the inverter motor.To determine at least one performance parameter, the simulation software can include a physics module that can, for example, simulate heat release in components of the inverter motor (i.e., its virtual representation) and / or an electrical value such as a bearing current in one of the inverter motor's bearings. In a subsequent fourth step, the performance parameter determined in the third step is output to a user and / or a data interface. The simulation software can be connected via the data interface to, for example, a higher-level control unit of an automation system in which the inverter motor being simulated is located. This data interface can be implemented as an Application Programming Interface (API).Furthermore, the simulation software product can be connected to the inverter motor being simulated via a data interface and thereby receive data corresponding to at least one performance parameter and / or at least one operating parameter. Accordingly, the simulation software product can be designed as a digital twin. The digital twin is to be understood in the sense of US 2017 / 286572 Al. The disclosure content of US 2017 / 286572 Al is incorporated by reference into the present application.

[0035] The underlying design of the inverter motor allows for the simple minimization of bearing currents. Partial discharge activity within the motor is also minimized, thus protecting its insulation. Furthermore, bearing currents through the motor bearings are reduced. Consequently, the effects of bearing currents on bearing degradation are negligible. Alternatively or additionally, the electrical loads on the bearings resulting from the bearing currents can be described in a simplified way as a degradation component. As a result, the claimed simulation program product can be based on a simplified degradation model for the bearings that ignores the effect of bearing currents. Models with high predictive accuracy exist for such applications. Accordingly, the claimed simulation program product offers a high degree of realism.Furthermore, the simulation software requires relatively little computational effort, which in turn leads to particularly fast simulations. The simulation software can therefore also achieve real-time capability, meaning it can run concurrently with operation. This allows for more precise monitoring of the underlying inverter motor, which in turn enables particularly efficient operation. The operation of an automation system equipped with such a simulation software is thus safer and more efficient overall.

[0036] The invention is explained in more detail below with reference to individual embodiments shown in the figures. The figures are to be read as complementary to each other, such that identical reference numerals in different figures have the same technical meaning. Furthermore, the features of the embodiments shown in the figures can be combined with the features outlined above. Specifically, Figure 1 shows a schematic diagram of an embodiment of the claimed inverter motor;

[0037] FIG 2 shows a further schematic diagram of the embodiment of the claimed inverter motor;

[0038] FIG. 1 schematically shows a longitudinal section of an embodiment of the claimed inverter motor 10. The inverter motor 10 essentially comprises a motor 20 and an inverter 30, which are arranged in a housing 22. The motor 20 comprises a stator 24 and a rotor 26, which is mounted on a rotor shaft 23. The rotor shaft 23 is supported in two bearings 28 and rotatably mounted in them about an axis of rotation 15. The bearings 28 are located in the wall of the housing 22 on a drive side 12 and a non-drive side 14 of the inverter motor 10. The stator 24 and the rotor 26, i.e., the active components of the motor 20, are arranged between the bearings 28 along the axial direction, i.e., along the axis of rotation 15. The converter 30 and its components, which include circuit boards 32 with semiconductor switches 34, are also arranged in the axial direction between the bearings 28.The inverter 30, i.e., all of its components, is arranged in a common motor compartment 25, as are the stator 24 and the rotor 26. The spatial distance 27 between the inverter 30 and the rotor 26 or the stator 24, i.e., along the axial direction, is minimized. Furthermore, the space between the stator 24 and the rotor 26 is free of partitions. The inverter 30, i.e., one of its circuit boards 32, is electrically connected directly to the stator 24, i.e., to an associated stator winding, via a plug connector 21. A high-frequency current transducer 49 (HFCT) can be arranged in the area of ​​the plug connector 21, which can be used to detect partial discharge activity in one of the motor windings. Alternatively or additionally, a temperature sensor 19 can be used as an antenna to detect partial discharge activity.As a result, there is a reduced impedance 29 between the inverter 30 and the stator 24, which is lower than the impedance 37 between the inverter 30 and each of the bearings 28. The impedances 37 between the inverter 30 and the bearings 28, as well as the impedance 29 between the inverter 30 and the stator 24, are symbolized by dashed arrows in FIG. 1. This minimizes bearing currents, i.e., electrical currents through the bearings 28, during normal operation of the inverter motor 10.

[0039] The inverter motor 10 has a terminal box 44 through which the inverter 30 is electrically connected to a power supply 31. The inverter motor 10 is further equipped with at least one temperature sensor 19, which is arranged to detect a temperature on a component of the inverter 30, for example, on a printed circuit board 32 with semiconductor switches 34. The temperature sensor 19 is configured to transmit measurement signals 17 to an evaluation unit 45, which belongs to a control unit 40 of the inverter motor 10. The control unit 40 can be arranged inside or outside the inverter motor 10. Furthermore, the inverter motor 10 has a measuring device 16, which is attached to the rotor shaft 23 as a shaft-ring arrangement and is configured as a voltage measuring device.The measuring device 16 is also connected to the evaluation unit 45 in the control unit 40 and is capable of transmitting measurement signals 17 to the evaluation unit 45. The measuring device 16 is designed to detect bearing currents at the associated bearing 28 and / or discharge activities at it. In addition, the inverter motor 10 is equipped with a vibration sensor 18, which is designed to detect vibrations in the area of ​​the bearing 28. Based on this, the degradation level of the associated bearing 28 can be determined. The degradation level can also be determined by including detected electrical loads on the bearings 28. The measurement signals 17 from the vibration sensor 18 are also transmitted to the evaluation unit 45 in the control unit 40. The received measurement signals 17 can be processed individually or in combination by a computer program 50, which is functionally part of the evaluation unit 45.Furthermore, the control unit 40 is equipped with a computer program product 50, which is configured to send control commands (not shown) to the inverter motor 10, in particular to its inverter 30. The computer program product 50 is configured to interact with the computer program product 50 in the evaluation unit 45.

[0040] Furthermore, a simulation program product 60 runs on the control unit 50. This program is designed to replicate, i.e., simulate, the operating behavior of the inverter motor 10. For this purpose, the simulation program product 60 includes a digital twin 65 of the inverter motor 10. The simulation program product 60 is coupled to the measuring device 16, the vibration sensor 18, and / or the temperature sensor 19 and is capable of comparing their measurement signals 17 as the actual state with a state of the digital twin 65. The control unit 40 is also connected to a data interface 53, which is designed to output a determined degradation level and / or an expected remaining technically usable service life of a component of the inverter motor 10, for example, to a higher-level control unit of an automation system to which the inverter motor 10 belongs.Alternatively or additionally, the state of the digital twin 65 can be output via the data interface 53. Likewise, the control unit 40 is connected to a display unit 54, which can also output a determined degradation level and / or an expected remaining technically usable service life of a component of the inverter motor 10, for example to a higher-level control unit of an automation system to which the inverter motor 10 belongs. Furthermore, the state of the digital twin 65 can also be output via the display unit 54.

[0041] The inverter motor 10 according to the embodiment shown in FIG. 1 is shown schematically in more detail in FIG. 2. In particular, the electrical configuration of the claimed inverter motor 10 is shown in more detail in FIG. 2. The inverter motor 10 is connected to a power supply network 31, which provides the inverter motor 10 with energy. The inverter motor 10 comprises a motor 20, which is supplied with energy via the inverter 30. The inverter 30 has a DC link 35 and an inverter 43 in which its semiconductor switches 34 are arranged. The motor 20 is connected to the inverter 30, which has a reduced impedance 29, via the plug connector 21. The impedance 29 between the stator and the DC link 35 is lower than the impedance 37 between the inverter 30 and the bearings 28 of the motor 20, as shown in FIG. 1.This prevents currents from flowing from the stator 24 through the bearings 28 back into the inverter 30, where an increased impedance 37 exists along this path. Instead, currents from the stator 24 can flow directly from the housing 22 into the inverter 30. As a result, bearing currents through the bearings 28, as shown in FIG. 2, are minimized or even prevented.

[0042] By actuating the semiconductor switches 34, a pulse-width modulated voltage is supplied to the motor 20 during normal operation. This voltage, which is variable in frequency and amplitude, results in a predefined motor current. The semiconductor switches 34 can be controlled, i.e., switched, via a control unit 40 of the inverter motor 10 by means of control commands 42. During normal operation, the semiconductor switches 34 are actuated at a predefined switching frequency 38. Depending on the switching frequency 38, varying degrees of power loss, i.e., heating, occur in the motor 20 and / or the inverter 30. The control unit 40 is designed to set the switching frequency 38 in a predefined manner and thus influence the heating behavior of the motor 20 and / or inverter 30.Furthermore, electrical feedback 41 from the motor 20 primarily affects the DC link 35 and leads to bearing currents only to a minimal extent. This allows the inverter motor 10 to be operated in a particularly efficient manner.

[0043] The control unit 40 comprises an evaluation unit 45, which, by means of a running computer program 50, is configured to receive and process measurement signals 17 from the measuring device 16, the vibration sensor 18, the high-frequency current transducer 49, and / or the temperature sensor 19, as shown in FIG. 1. The computer program 50 in the evaluation unit 45 interacts with the computer program 50 on the control unit 40. Furthermore, the state of the inverter motor 10 is simulated in a simulation program 60 for monitoring purposes, i.e., its operation is simulated. [Reference numeral list]

[0044] 10 Inverter motor

[0045] 12 Drive side

[0046] 14 Non-drive side

[0047] 15 axis of rotation

[0048] 16 Measuring device

[0049] 17 measurement signals

[0050] 18 vibration sensors

[0051] 19 Temperature sensor

[0052] 20 engine

[0053] 22 cases

[0054] 23 Rotor shaft

[0055] 24 Stator

[0056] 25 Engine compartment

[0057] 26 Rotor

[0058] 27 distance

[0059] 28 warehouses

[0060] 29 space

[0061] 30 inverters

[0062] 31 repercussions

[0063] 32 Inverter component

[0064] 33 network

[0065] 34 semiconductor switches

[0066] 35 Intermediate circle

[0067] 36 lines

[0068] 37 Impedance

[0069] 38 switching frequency

[0070] 39 lines

[0071] 40 Control unit

[0072] 42 Control command

[0073] 45 evaluation units

[0074] 50 Computer program product 53 Data interface

[0075] 54 Display unit

[0076] 60 Simulation program product 65 Digital Twin

Claims

Patent claims 1. Inverter motor ( 10) comprising a housing (22 ), a motor (20) with a stator (24 ) and a rotor (26) on a rotor shaft (23) rotatably mounted on two bearings (28 ), and an inverter (30) wherein the stator (24 ), the rotor (26) and the inverter (30) are accommodated in the housing (22 ), characterized in that the inverter (30) with the rotor (26) and the stator (24 ) is arranged in a common motor compartment (25) in the housing (22 ) between the bearings (28 ).

2. Inverter motor ( 10) according to claim 1, characterized in that an intermediate space between the inverter ( 30) and the rotor (26) is designed without partition walls .

3. Inverter motor ( 10) according to claim 1 or 2, characterized in that at least one temperature sensor ( 19) for detecting an operating temperature of the inverter (30), the stator (24 ) and / or the rotor (26) is arranged in the housing (22 ) and a control unit (40) of the inverter motor ( 10) is configured to specify a switching frequency (38 ) of the intermediate circuit (35) of the inverter (30) depending on measured values ​​of the at least one temperature sensor ( 19).

4. Inverter motor ( 10) according to one of claims 1 to 3, characterized in that the control unit (40) is configured to adapt and specify a switching frequency (38 ) of the inverter (43) for psychoacoustic optimization of a noise emission of the inverter motor ( 10).

5. Inverter motor (10) according to one of claims 1 to 4, characterized in that the control unit (40) is configured to specify the switching frequency (38) of the inverter (43) for specifying a distribution of power losses at the motor (20) and at the inverter (30).

6. Inverter motor (10) according to one of claims 1 to 5, characterized in that the motor (20) is configured with a measuring device (16) for detecting an electrical quantity and the control unit (40) is configured to detect a discharge activity at an insulation on the basis of the electrical quantity.

7. Inverter motor ( 10) according to claim 6, characterized in that the measuring device ( 16) is designed as a voltage measuring device, in particular as a ring-shaft arrangement for non-contact voltage measurement .

8. Inverter motor ( 10) according to one of claims 1 to 7, characterized in that a vibration sensor ( 18 ) is arranged on at least one of the bearings (28 ).

9. Inverter motor ( 10) according to claims 7 and 8, characterized in that the inverter motor ( 10) has an evaluation unit (45) which is designed to determine, on the basis of measurement signals ( 17 ) from the voltage measuring device and the vibration sensor ( 18 ), a degradation level and / or an expected technically usable remaining service life of the at least one bearing (28 ).

10. Inverter motor ( 10) according to one of claims 1 to 9, characterized in that the evaluation unit (45) is designed to predict a technically usable remaining service life of insulation on the rotor (26) and / or stator (24 ).

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