WO2022018174A1

WO2022018174A1 - Operating a drive device

Info

Publication number: WO2022018174A1
Application number: PCT/EP2021/070465
Authority: WO
Inventors: Walter Marx
Original assignee: Siemens Energy Global GmbH & Co. KG
Priority date: 2020-07-23
Filing date: 2021-07-22
Publication date: 2022-01-27
Also published as: DE102020209302A1

Abstract

The invention relates to a method for operating a drive device (10) having a rotating electric machine (20) which has a stator (22) having a magnetic unit (24) and a rotor (28), wherein the magnetic unit (24) has grooves (30), a first winding strand (32) and a second winding strand (34), electrically isolated from the first winding strand (32), being arranged in each groove (30), and an inverter arrangement (36) having a plurality of inverters (40, 42, 44, 46), wherein a first winding strand (32) is connected to a first inverter (40, 42) and a second winding strand (34) is connected to a second inverter (44, 46), wherein the inverters apply an identical specified electrical current to the winding strands (30, 32). According to the invention, in an operating state in which one of the first inverters (40) cannot be activated, the second inverter (44) is controlled such that the doubled specified electrical current is applied to the second winding strand (34).

Description

description

Operating a drive device

The invention relates to a method for operating a drive device, in particular for a watercraft, the drive device having a rotating electrical machine which has a stator having a magnetic unit and a rotor which is arranged such that it can rotate with respect to the stator and is spaced apart from the magnetic unit by an air gap , wherein the magnetic unit has slots formed on the air gap side, a first phase winding being arranged in each slot and a second phase winding electrically insulated from the first phase winding being arranged, and having an inverter arrangement which has a plurality of inverters. According to a first aspect, a respective first winding phase is connected to a respective first inverter of the inverter arrangement and a respective second winding phase is connected to a respective second inverter of the inverter arrangement, the inverters being controlled in such a way that the winding phases have the same predetermined electrical Current are applied. According to a second aspect, one phase winding with a first connection is connected to one inverter in each case, with two first phase windings of two respective slots arranged immediately adjacent and two second phase windings of these slots being connected in series via respective second connections, and in a first operating state, only a predetermined selection of the inverters of the inverter arrangement is activated, with a drive power to be provided in the first operating state being less than a partial power of the inverter arrangement that can be provided by the activated inverters, which is determined as a function of a maximum electric current that can be provided by the activated inverters and in a second operating state in which the drive power to be provided is greater than the partial power, all inverters of the inverter arrangement are activated. The invention also relates to propulsion devices, in particular for a watercraft, with a rotating electrical machine that has a stator that has a magnetic unit and a rotor that is rotatably arranged relative to the stator and is spaced apart from the magnetic unit by an air gap, the magnetic Unit has grooves formed on the air gap side, with a first winding phase being arranged in each groove and a second winding phase electrically insulated from the first winding phase being arranged, an inverter arrangement having a plurality of inverters, wherein, according to the first aspect, a respective first winding phase is connected to one respective first inverter of the inverter arrangement is connected and a respective second phase winding is connected to a respective second inverter of the inverter arrangement, and a control device for controlling the inverter he who is designed to control the first and the second inverters in such a way that the first and the second inverters apply the same predeterminable electric current to the respective phase windings. Furthermore, according to the second aspect, one phase winding is connected to an inverter with a first connection, with two first phase windings of two respective immediately adjacent slots and two second phase windings of these slots being connectable in series via respective second connections, with the control device for controlling the inverters is designed to activate only a predetermined selection of the inverters of the inverter arrangement in a first operating state, wherein in the first operating state a drive power to be provided is less than a partial power of the inverter arrangement that can be provided by the activated inverters, which depends on a is determined in each case by the activated inverters, and in a second operating state in which the drive power to be provided is greater than the partial power, activate all inverters of the inverter arrangement.

Generic propulsion devices, watercraft with such propulsion devices as well as methods for their operation are known in the prior art. The drive device, also known as the electric drive device, serves, among other things, to be able to implement a drive function in vehicles, in particular in watercraft, during normal operation of the vehicle or ferry operation. For this purpose, the drive device can be connected to a drive shaft. The drive shaft can be directly non-rotatably connected, for example, to the rotor of the electrical machine. The drive device of the generic type can be used particularly advantageously in watercraft, in particular in underwater boats. FITS in underwater boats, the generic drive device proves to be advantageous because it can be achieved that a ship's propeller can be directly connected to the rotor or a rotor shaft of the rotor, rotatably. A gear can be avoided. At the same time, the drive device makes it possible to keep noise development or sound emission by the drive device as low as possible by suitably controlling the inverters. This is not only advantageous for water vehicles in general, but also particularly for submarines, as a result of which their locatability can be reduced.

A generic drive device is disclosed, for example, by WO 2004/068694 A1, which discloses an electrical machine for the propulsion drive of a submarine with a permanent magnetically excited synchronous machine. The drive device of WO 2004/068694 A1 is intended to achieve increased availability of the drive function through redundancy, with machine noise being able to be reduced. Even if the teaching of WO 2004/068694 A1 has proven itself, disadvantages still remain. It has been shown that in the aforementioned construction, a defect in an inverter can lead to significant restrictions on the intended operation. This is particularly unfavorable for underwater boats. In this context, the aforementioned construction proves to be disadvantageous in that a repair or corresponding maintenance cannot generally be carried out during normal ferry operation. The aforesaid construction requires that the drive device has to be laboriously dismantled in order to be able to replace or maintain the respective inverter or a respective inverter module. This type of repair or maintenance is therefore only possible for watercraft in the roadstead or in the port.

Although there is the possibility of being able to continue ferry operations using the redundancy with correspondingly reduced power, this is unfavorable for watercraft, in particular underwater boats, and can result in dangerous conditions. It has proven to be particularly disadvantageous that the drive device of the faulty inverter can cause increased noise emissions. This not only proves to be disruptive during normal operation, but also, particularly in the case of submarines, can undesirably increase their locatability.

The invention is therefore based on the object of developing a generic drive device, a generic watercraft and a method for operating the drive device in such a way that improved availability can be achieved in the event of a fault in an inverter. It should preferably be possible to reduce sound emissions from the drive device.

As a solution, the invention drives devices and methods according to the first and the second aspect and a Watercraft according to the independent claims proposed.

Advantageous developments result from features of the dependent claims.

With regard to a generic method, it is proposed according to the first aspect, in particular, that in an operating state in which one of the first inverters cannot be activated, the respective second inverter is controlled in such a way that the respective second phase winding is acted upon by twice the specified electric current when the specified electric current is less than a maximum electric current that can be provided by the respective second inverter.

With regard to a generic method according to the second aspect, the invention proposes in particular that, in the case of a non-activatable inverter that is connected to a respective first winding phase, in the second operating state the inverter that is connected to the respective second winding phase is is controlled that this second phase winding is acted upon by the maximum electric current that can be provided.

With regard to a generic drive device according to the first aspect, the invention proposes in particular that the control device is also designed, in an operating state in which one of the first inverters cannot be activated, to control the respective second inverter in such a way that the respective second winding strand is acted upon by twice the predefinable electric current if the predefinable electric current is less than a maximum electric current that can be provided by the respective second inverter. With regard to a generic drive device according to the second aspect, the invention proposes in particular that the control device is also designed, in the case of a non-activatable inverter that is connected to a respective first phase winding, in the second operating state to control the inverter that is connected to the each respective second phase winding is connected to control such that this second phase winding is acted upon by the maximum electric current that can be provided.

With regard to a generic watercraft, the invention proposes in particular that the drive unit be designed according to the invention.

The invention is based, among other things, on the idea that in the case of a non-activatable inverter or a non-activatable inverter module, the operation of the drive device can not only be continued, but also noise development, for example due to an asymmetrical operating situation of the inverter arrangement, can be significantly reduced if at least a limited compensation can be created with the remaining inverters of the inverter arrangement. If an inverter or an inverter module cannot be activated as intended, for example due to a fault, a defect, an insulation fault or another undesirable event, not only can the partial operation of the drive unit be significantly reduced without major losses in terms of noise development to have to accept, son countries by the operational management according to the invention, a significantly improved operation can be rea lisiert even at higher power, with effects on the noise development development by the drive device can still be largely small. This is particularly important in the case of watercraft, such as underwater boats or the like. In contrast to the prior art, it is therefore no longer absolutely necessary to produce a high level of performance of the drive device to repair the inverter arrangement by replacing the corresponding inverter or a corresponding inverter module. Rather, it is possible to maintain a high level of performance with low noise development through targeted operational management of the drive device, in particular the inverter arrangement.

In the case of a watercraft, it is therefore normally not necessary to continue driving with the defective inverter or inverter module until the next time it is in a port or on roadsteads. The acoustic properties of the drive device can therefore be maintained at least partially.

The invention avoids, on the one hand, that there is no longer any magnetic flux in the slot with the phase winding without current due to the non-activatable inverter. An increase in the double or quadruple electrical frequency of the drive device, in particular of the inverter arrangement, can thus be reduced, if not avoided altogether. In addition, on the other hand, the inverters, especially in the case of series connection of winding strands, do not need to be switched to parallel operation, which would require all remaining inverters to be operated with the same clock frequency, which results in a significant acoustic noise emission could have, which would not occur in undisturbed normal operation.

The slots of the magnetic unit extend from one axial end of the magnetic unit or the stator to an opposite axial end of the magnetic unit or the stator. The grooves are preferably arranged on the inside of a substantially circular peripheral opening of the stator or of the magnetic unit, namely substantially co-axially to an axis of rotation of a aisle opening arranged rotor when the rotating electrical machine is an internal rotor. In the case of an external rotor, the grooves can be arranged correspondingly on an outer circumference of the magnetic unit.

Each slot has at least one first phase winding and at least one second phase winding which is electrically isolated from the first phase winding. A phase winding can be formed by an electrical conductor of a stator winding of the stator or of the magnetic unit. The magnetic conductor can have a round cross-section or else an angular cross-section, in particular a rectangular cross-section. The winding strands can be arranged one above the other and/or next to one another in the slot. A phase winding can also have more than a single electrical conductor. If there are several conductors, they can be connected in series or in parallel.

The grooves extend essentially parallel to the axis of rotation. Depending on the design, however, it can also be provided that the grooves are formed at an angle relative to the axis of rotation.

In the first aspect, a respective first phase winding is connected to a respective first inverter of the inverter arrangement and a respective second winding phase is connected to a respective second inverter of the inverter arrangement. At least a first respective connection of a respective phase winding is thus also connected to a respective inverter. However, the respective phase windings are preferably connected to the respective inverter with their first connection and also with their respective second connection. In this case, the respective inverter comprises at least one full-bridge circuit made up of switching elements, which are operated in switching operation when the inverter is operated as intended. The full bridge circuit usually includes two series circuits of at least two series-connected ted switching elements. The series circuits are connected in parallel on the circuit side. The first and the second connection of the respective phase winding are connected to the respective center taps of the series circuits.

A switching element can be formed by one or more semiconductor switching elements. In addition, the switching element can also include an electromechanical switching element, for example a relay, a contactor and/or the like. In principle, the semiconductor switching element can also be formed by an electromechanical switching element or any other suitable switching element.

The switching element, in particular the semiconductor switching element, can be replaced by a transistor, in particular a field effect transistor, preferably a metal oxide field effect transistor (MOSFET), an insulated gate bipolar transistor (IGBT), but also by a gate turn-off thyristor (GTO ) and/or the like or any other type of switching elements.

In order to provide the desired current through the inverter, the semiconductor switching elements are operated in switching mode. With regard to a semiconductor switching element using a transistor, the switching operation means that in a switched-on switching state, a very small electrical resistance is provided between the terminals of the transistor that form a contact gap, so that a high current flow is possible with a very small residual voltage.

In a switched-off switching state, on the other hand, the switching gap of the transistor has a high resistance, i.e. it provides a high electrical resistance, so that even with a high electrical voltage applied to the switching gap, there is essentially no or only a very small, in particular negligible, current flow. This differs from linear operation with transistors. The control unit is connected at least to the switching elements, in particular the semiconductor switching elements of the inverters. Each inverter preferably has its own communication interface, by means of which it is in communication with the control device. As a result, the control device can also be used to control activation or deactivation of the respective inverter.

The control unit itself can be pre-see as a separate unit. However, it is preferably part of the inverter arrangement and is particularly preferably integrated into it.

During normal operation, the inverters are controlled in such a way that the phase windings are subjected to the same predetermined electric current. The specified electric current can be dependent, for example, on a drive power to be set, a drive torque to be set and/or the like. Preferably, the specified electric current is specified by a control device or the like connected to the control device. For this purpose, the control device can have a corresponding hardware circuit and/or a correspondingly designed program-controlled computing unit.

According to the first aspect, it is proposed that in an operating state in which one of the first inverters cannot be activated, the respective second inverter is controlled in such a way that the respective second phase winding, which is in the same slot as the first inverter connected to the first Phase winding is arranged, is acted upon by twice the predetermined electric current when the predetermined electric current is less than the maximum electric current that can be provided by the respective second inverter. This can be achieved that as long as the specified electric current is less than the The maximum current that can be provided by the respective second inverter can compensate for this functional failure by providing or loading the respective second phase winding in the slot in which the first phase winding is currentless because the inverter cannot be activated. By acting on this second phase winding with twice the specified electric current, it can be achieved that the corresponding magnetic pole is nevertheless acted upon by the same mag netic flux. Therefore, as long as the specified electrical current is less than the maximum current that can be provided by the second inverter, almost complete compensation for the failure of the respective first inverter can be achieved.

With regard to the first aspect, it is also proposed that the respective second phase winding is acted upon by the maximum electric current that can be provided if the specified electric current is greater than the maximum current that can be provided. This makes it possible to at least partially compensate for the effects of the first inverter that cannot be activated by operating the second inverter accordingly. As a result, at least partial compensation can be achieved because, for technical reasons, the maximum electric current that can be provided by the second inverter generally cannot be increased any further when there is an increased power requirement. However, compared to a total failure, a significant improvement can still be achieved.

Because a first phase winding and a second phase winding are arranged in each slot and are electrically insulated from one another, it is possible, if only a small amount of drive power is required by the drive device, to operate some of the inverters at partial power, for example around half of the To disable inverters, preferably either those inverters that are connected to the first phase windings are connected, or the inverters, which are connected to the second phase windings. Particularly in the last-mentioned case, it can be achieved that each of the slots continues to be subjected to a magnetic flux. As a result, a good degree of efficiency with low noise emission can be guaranteed by the drive device even in partial power operation. This operating state—referred to below as the low-power operating state—can be advantageously used particularly for low speeds of the watercraft, for example when maneuvering or when crawling, for example in an underwater boat or the like. The low-power operating state can extend to a drive power that is determined by the respective maximum electric current that can be provided by the inverter. Depending on requirements, this low-power operating state can also only be implemented down to a lower power level.

The low power operating state can be followed by a partial power operating state which, according to the second aspect, provides for a respective series connection of first and second winding strands arranged in immediately adjacent slots. In this partial power operating state, it is therefore provided for two immediately adjacent slots that the respective first winding strands are connected in series. The respective second phase windings are also connected in series for the same slots.

According to a further development, it is proposed that the drive device has a switching unit which is designed to switch the respective winding strands in series in a first switching state. Provision can thus be made for a corresponding switching unit to be provided, which can provide the corresponding switching states for the phase windings in order to be able to switch between the partial power operating state and the low-power operating state. The switching unit can be, for example, an electromechanical switching unit, the electromechanical switching elements such as relays, contactors and/or the like uses. In addition, the switching unit can of course also have electronic switching elements for realizing the respective switching functions. A combination of these can also be provided.

Each inverter of the inverter arrangement is connected to a single phase winding, specifically at a first connection of the respective phase winding. The second connections of the phase windings are electrically connected to one another in a predetermined manner, for example via the switching unit, in order to form the respective series circuits. This means that in each case two series-connected phase windings are connected to their respective end connections or first connections to inverters. As a result, both electrical ends of the series circuit are formed by respective first connections of the phase windings and are electrically connected to a respective inverter. This partial power operating state has the advantage that a high level of efficiency can still be achieved for the specified partial power range. At the same time, this type of circuit in conjunction with the inverter operation can continue to reduce the noise generated by the drive device.

Furthermore, at least two operating states are possible for the partial power operating state, namely a first operating state and a second operating state, as explained below.

In the first operating state, only a predetermined selection of the inverters in the inverter arrangement is activated.

This can be a selection that is also provided for the low-power operating mode. In the first operating state, a drive power to be provided is less than a partial power of the inverter arrangement that can be provided by the activated inverter, which depends on is determined by a maximum electric current that can be provided by the activated inverters. The maximum electrical current that can be provided by an inverter is preferably the current that, for technical reasons, can be provided by the respective inverter as a maximum at an AC voltage connection of the inverter that is electrically coupled to a respective phase winding. Here, too, provision can be made for the first operating state to extend to the partial performance. However, it can also only extend to a smaller part of the service.

In the second operating state, in which the drive power to be provided is greater than the partial power, all the inverters of the inverter arrangement are activated. For example, it can be provided that in the first operating state only the series-connected first winding strands are supplied with electric current. Alternatively, it can be provided that only the second phase windings connected in series are supplied with electric current. Of course, provision can also be made for switching between these two aforementioned configurations. Combinations of these can also be provided, in particular if at least one winding strand is supplied with electric current in all slots.

If, for example, due to a given reason--as explained above--an inverter cannot be activated in the second operating state, this would lead not only to reduced drive power but also to significant noise development. This can be improved in that, in the case of a non-activatable inverter that is connected to a respective first winding phase, the inverter that is connected to the respective second winding phase is controlled in the second operating state in such a way that this second winding phase is operated with the maximum - Electric current that can be ridden is applied. This can lead to the failure of the non-activatable inverter be at least partially compensated, so that the noise development can also be reduced.

If, on the other hand, the problem of the inverter that cannot be activated occurs in the first operating state, it is only necessary to switch between the inverters connected to the first winding strands and the inverters connected to the second winding strands. In the first operating state, therefore, full redundancy can be achieved in relation to the failure of an inverter. In contrast, in the second operating state, the failure of the inverter can be at least partially compensated.

In addition, based on the low-power operating state, a full-power operating state can be provided, in which the series connection in the partial-power operating state is dissolved and each phase winding is operated on a respective inverter. The phase windings are preferably connected with both terminals to the respective inverter, which is designed for this purpose, for example, in a full-bridge circuit. Basically, however, there is also the possibility of operating the respective phase windings in a star connection, as a result of which the inverter only needs to be designed as a half-bridge circuit.

With regard to the second aspect, it is also proposed that the selection be specified in such a way that at least one phase winding is supplied with electric current in each slot. This has the advantage of uniform stress on the drive device and a further reduction in noise.

In addition, it is proposed that an inductance is connected in series with a respective series connection of two phase windings. The inductance can also be connected in series by means of the switching unit. This allows the efficiency to further increase improve, in particular the clock frequencies of the inverters can be set almost independently of one another. This also has the advantage of further reducing noise and interference.

It is also proposed that a sound emitted by the drive device is detected by means of a sound sensor and that the inverters are controlled as a function of the detected sound. This has the advantage that the inverters can be controlled accordingly, for example in relation to the clock frequency, so that overall the sound output from the drive device can be further reduced. For this purpose, corresponding evaluation and control algorithms can be implemented by the control device, which can have a hardware circuit and/or a program-controlled computer unit for this purpose, for example. For example, the control device can be used to wobble in relation to the clock frequency of the respective inverter, so that noise can be reduced and interference can be emitted in the area of wired radio interference and/or the like.

It is also proposed that the inverter arrangement has inverter modules, with a respective inverter module comprising two of the inverters that are connected in parallel between the intermediate circuit side, with two series-connectable phase windings being connected to the inverters of a respective inverter module. The inverter modules can be designed as individually manageable assemblies that can preferably be provided and tested separately. For this purpose, the inverter modules can have their own housing, for example. The housings can be designed to be connected to one another. Thus, an improved construction, in particular in relation to maintenance and manufacture of the drive device can be achieved. The inverter modules make it possible to construct the drive device in a very compact and modular manner. At the same time, through the inverter modules too a simple connection to the winding strands and an electrical energy supply for the inverters can be realized. The inverter modules can be implemented as individually manageable structural units. The inverter modules can form individually testable units.

In addition, it is proposed that the switching unit be designed to couple the respective first and second connection of a respective phase winding to a single respective inverter of a respective inverter module in a second switching state. This allows a simple switchover function to be implemented that requires little wiring effort. In addition, the winding strands can be supplied with electricity in almost any way and independently of one another.

It is also proposed that the inverter modules are designed as separately manageable components, with the inverter modules being arranged adjacent to one another in the circumferential direction within a stator opening that is coaxial with an axis of rotation of the rotor. As a result, the inverter arrangement can be easily integrated into the rotating electrical machine, so that a separate construction of the inverter arrangement, which is arranged separately from the rotating electrical machine, can be saved. A high level of integration with respect to the drive device can be achieved with this design, in particular if the rotating electrical machine has a large outer circumference and/or a large number of poles. The inverter modules can be designed, for example, in the manner of circular sectors and be arranged adjacent to one another in the circumferential direction. The inverter modules are preferably arranged in such a way that they are essentially opposite the phase windings connected to them, so that the wiring effort can be reduced. In addition, a reduction in electromagnetic interference and/or noise can also be achieved with this configuration. The rotor advantageously has a rotor opening which is formed coaxially to the axis of rotation and in which the inverter arrangement is at least partially formed. The inverter arrangement is preferably arranged essentially completely in the rotor opening. This configuration is particularly suitable for electrical machines that have a large diameter with a large number of poles. As a result, a space within the rotating electrical machine can be used to accommodate the inverter arrangement. The drive device can be made very compact in this way. The rotor opening can be formed, for example, by forming the rotor in the area of the stator winding in the manner of a bell and/or, for example, having a blind opening at the end, in which the inverter modules of the inverter arrangement can be arranged. Even if the use of inverter modules is advantageous here, this idea is not limited to this. Basically, the inverter arrangement can of course also be provided as a compact unit that includes the individual inverters.

The rotor is advantageously designed to be permanently excited. In this way, a synchronous machine can be implemented in which the rotor does not require any electrical connections. This not only has advantages for the intended operation but also for safety. This proves to be advantageous, especially in the case of drives for water vehicles.

The advantages and effects specified for the method according to the invention naturally apply equally to the drive devices according to the invention and the watercraft equipped with the drive devices according to the invention and vice versa. In particular, method features can be formulated as device features and vice versa. Further advantages, effects and features result from the following description of exemplary embodiments. In the exemplary embodiments, the same reference symbols denote the same features and functions.

The exemplary embodiments explained below are preferred embodiments of the invention. The features and combinations of features specified above in the description and also the features and combinations of features mentioned in the following description of exemplary embodiments and/or shown alone in the figures can be used not only in the combination specified in each case, but also in other combinations. The invention also encompasses or is to be regarded as disclosed embodiments that are not explicitly shown and explained in the figures, but that result from the explained embodiments and can be generated through separate combinations of features. The features, functions and/or effects illustrated in the exemplary embodiments can each represent individual features, functions and/or effects of the invention that are to be considered independently of one another and that further develop the invention independently of one another. Therefore, the exemplary embodiments are also intended to include combinations other than those in the illustrated embodiments. In addition, the described embodiments can also be supplemented by further features, functions and/or effects of the invention that have already been described.

1 shows a schematic basic view of a drive unit for a submersible with a permanently excited synchronous machine and an inverter arrangement integrated in the synchronous machine;

2 shows a schematic sectional view of a magnetic unit of a stator and a rotor of the synchronous machine according to FIG. 1; 3 shows an enlarged representation of a region III in FIG. 2 connected to the inverter arrangement;

4 shows a schematic circuit diagram of an inverter module of the inverter arrangement according to FIG a first switching state is shown;

FIG. 5 shows a schematic circuit diagram like FIG. 4, in which the switching unit is shown in a second switching state; and

6 shows a schematic side view of a submersible with the drive device according to FIG.

FIG. 6 shows a schematic side view of a submarine 12 as a watercraft which has an electric drive unit 10 which is used for the intended ferry operation of the submarine 12 . The electrical drive device 10 has a permanently excited synchronous machine 20 and an inverter arrangement 36, which are designed to be integrated into a compact unit (FIG. 1), as will be explained further below.

The synchronous machine 20 includes a rotor 28 which is non-rotatably connected to a first end of a drive shaft 16 ei. A propeller 18 is fastened in a rotationally fixed manner to a second end of the drive shaft 16 opposite the rotor 28 . Thus, with the electric drive device 10, the drive shaft 16 in connection with the propeller 18 can bar, that is, without the interposition of a mechanical Ge transmission, driven in rotation.

The inverter arrangement 36 of the electric drive unit 10 is connected to a vehicle battery 14 of the underwater boat 12 on the DC voltage intermediate circuit side, which provides electrical energy for the intended operation of the electric drive unit 10, in particular the inverter arrangement 36. What is not shown is that an internal combustion engine-driven unit can also be present, which is used to charge the vehicle battery 14 and/or alternatively to provide the electrical energy for the ferry operation of the submarine 12 on a water surface.

The electric drive device 10 includes the synchronous machine 20 as a rotating electric machine. The synchronous machine 20 has a stator 22 and a rotor 28 which is arranged such that it can rotate with respect to the stator 22 and is spaced apart from a magnetic unit 24 of the stator 22 by an air gap 26 . The synchronous machine 20 is presently designed as an internal rotor. However, the invention is not limited to this. The rotor 28 is arranged within a stator opening 64 of the stator 20, wherein the Stän deröffnung 64 is coaxial with an axis of rotation 60 of the rotor 28 is formed. In the present case, the stand opening 64 is substantially circular.

The rotor 28 is presently designed to be permanently excited, which is why it has permanent magnets arranged adjacent to one another in the circumferential direction on a surface facing the air gap 26 and which are arranged on a laminated rotor core (not shown).

On the stator side, the magnetic unit 24 is provided, which, in addition to a stator winding, which includes winding strands 32, 34, has a magnetic yoke, which in the present case is also designed as a laminated core. Depending on However, the magnetic yoke can be formed differently and, for example, have one or more magnetizable ferrite elements and/or the like. The stator opening 64 is presently provided by the magnetic unit 24 .

The magnetic unit 24 has grooves 30 formed on the air gap side. In this embodiment, the grooves 30 are open towards the air gap 26 . A first phase winding 32 is arranged in each slot 30 . In addition, a second winding phase 34 that is electrically insulated from the first winding phase 32 is arranged in each slot 30 . In the present embodiment, two winding strands 32, 34 are arranged in each groove so that they are electrically isolated from one another. Depending on the design of the synchronous machine 20, however, more than two winding strands that are electrically insulated from one another can also be arranged here. The phase windings 32, 34 are presently formed by conductor bars which are arranged in the respective slots. For example, it can be provided that the conductor bars have a substantially rectangular cross section, with an electrical insulation layer being arranged on the outer circumference of each conductor bar, which layer can include, for example, a lacquer, an insulation material such as mica or the like and/or the like . The grooves 30 can be at least partially closed by a suitable groove closure element (not shown).

It can also be seen that the runner 28 has a runner opening 66 which is coaxial with the axis of rotation 60 and which is embodied here as a blind opening. In this configuration, the rotor 28 is basically bell-shaped. In the present case, the inverter arrangement 36 is completely arranged in the rotor opening 66 . Depending on the design, however, it can also be provided that at least a part of the inverter arrangement 36 is arranged outside of the rotor opening 66, for example by placing this part in a separate inverter cabinet or the like. is ordered. The present construction is additionally shown in FIG. 2, which shows a schematic sectional view through the synchronous machine 20. FIG.

FIG. 3 shows a schematic representation of a section III from FIG. 2 in a plan view radially outward, the connection of the phase windings 32, 34 to the respective inverter 40, 42, 44, 46 of the inverter arrangement 36 being shown. It can be seen from FIG. 3 that a respective first phase winding 32 is connected to a respective first inverter 40, 42 of the inverter arrangement 36. A respective second phase winding 34 is connected to a respective second inverter 44, 46 of the inverter arrangement 36.

Furthermore, the electric drive device 10 comprises a control device 68, which is designed according to a first aspect, the first and the second inverters 40, 42,

44, 46 to be controlled in such a way that the first and the second inverters 40, 42, 44, 46 act on the respective phase windings 32, 34 in an undisturbed, intended operation with an essentially the same predeterminable electric current. As a result, operation of the electric drive device 10 can be achieved in an acoustically particularly quiet manner and with little interference in terms of electromagnetic compatibility.

With regard to the first aspect, the control device 68 is also designed, in an operating state in which one of the first inverters 40, 42 cannot be activated, to control the respective second inverter 44, 46 in such a way that the respective second phase winding 34 with the double th predetermined electric current is applied. An inverter cannot be activated, for example, if there is a disrupted operating state, the inverter cannot be controlled, has a hardware defect, the phase winding 32 connected to this inverter,

34 has an insulation fault and/or the like. In In this operating state, the reduced magnetic flux caused by this can thus be compensated for by the respective second inverter 44, 46, in that the water applies twice the predetermined electric current to the phase winding 34 connected to it. Since the second phase winding 34 is arranged in the same slot 30 as the first phase winding 32 in this case, the reduced magnetic flux through the operation of the second inverter 44, 46 in connection with the second phase winding 34 be compensated. This compensation is possible as long as the electrical current that can be predetermined is smaller than the maximum electrical current that can be provided by the respective second inverter 44, 46.

In the present embodiment, it is assumed that the inverters 40, 42, 44, 46 are of essentially the same design and have essentially the same electrical properties. However, this can also be deviated from in alternative configurations.

If the maximum specifiable electrical current is greater than a maximum electrical current that can be provided by the respective second inverter 44, 46, then only the maximum electrical current that can be provided is provided with the second inverter for charging the second phase winding 34. Accordingly, no further setting option needs to be provided here on the control side.

The maximum current that can be provided can relate to an effective value, an average value, an absolute value and/or the same of the electric current.

It can also be seen from FIG. 3 that the inverter arrangement 36 has inverter modules 48 , 50 . A jewei timed inverter module 48, 50 includes two of the inverters 40, 42, 44, 46, which are connected in parallel on the intermediate circuit side. Two windings that can be switched in series Strings 32, 34 are connected to the inverters 40, 42, 44, 46 of a respective inverter module 48, 50.

In addition, it can be seen from FIG. 3 that each inverter has a full-bridge circuit of switching elements, which in the present case are formed by transistors, namely insulated gate bipolar transistors (IGBT). In alternative configurations, however, the switching elements can also be formed by other semiconductor switching elements, for example field effect transistors such as in particular metal oxide semiconductor field effect transistors (MOSFET), but possibly also by gate turn-off thyristors (GTO) or the like. Combinations of these can of course also be provided.

Through the inverter modules 48, 50, a compact design of the inverter arrangement 36 can be achieved. This is illustrated with reference to FIG. In the rotor opening 66, the inverter modules 48, 50 are arranged circumferentially around the axis of rotation 60, adjacent to one another. A respective inverter module 48 is arranged directly adjacent to each respective inverter module 50 in the circumferential direction. The inverter modules 48, 50 are thus arranged ternating in the circumferential direction al. In addition, the inverter modules 48, 50 are formed in the circumferential direction in the manner of sectors of a circle. As a result, a very compact ter structure of the inverter arrangement 36 can be achieved within the rotor opening 66 and thus also the coaxial stator opening 64 .

4 and 5 show schematic circuit diagram arrangements of an inverter module 48 with the inverters 40, 42 (FIG. 4) and an inverter module 50 with the inverters 44, 46 (FIG. 5). In the present case, the inverters 40, 42, 44, 46 are configured essentially identically. Each inverter 40, 42, 44, 46 has two series connections each containing two switching elements, in this case IGBTs. The windings can be strands 32, 34 can be connected. Thus, in this case, each of the phase windings 32, 34 can be individually supplied with electrical current by a respective one of the inverters 40, 42, 44, 46. This operating state is shown in FIG.

According to a second aspect, it is also provided that one phase winding 32, 34 is connected to one of the inverters 40, 42, 44, 46 with a first connection 52, 54. This can be seen from FIGS. 3 to 5. Two first winding strands 32 of two slots 30 arranged immediately next to each other and two second winding strands 34 of each of these slots can be connected in series via respective second connections (FIG. 5).

In this second aspect, the control device 68 is designed to activate only a predetermined selection of the inverters of the inverter arrangement 36 in a first operating state. In the first operating state, a drive power to be provided is less than a partial power of the inverter arrangement 36 that can be provided by the activated inverters, which is determined as a function of a maximum electrical current that can be provided by the activated inverters. In the present embodiment, it is provided, for example, that the selection includes the inverters 40, 42 of the inverter module 48. In this operating state, the present embodiment provides that only half of the inverter modules 48, 50, namely the inverter modules 48, are activated. In contrast, the other inverter modules 50 are in the deactivated state. Alternatively, of course, the inverter modules 50 can also be activated and the inverter modules 48 can be deactivated.

This first operating state allows partial power operation to be implemented with high efficiency and low noise development. If the maximum partial output is reached in this first operating state, the control unit can be formed direction 68, in a second operational state, in which the drive power to be provided is greater than the partial power, all inverters 40, 42, 44, 46 of the inverter arrangement 36 or all inverter modules 48, 50 to activate.

In the case of an inverter 40, 42 that cannot be activated and that is connected to the respective first winding phase 32, the control device 68 is also configured to control the inverter 44, 46 that is connected to the respective second winding phase 34 in the second operating state in such a way that these second phase windings 34 are acted upon by the maximum electric current that can be provided. It can thereby be achieved that the loss of power due to the non-activatable inverter 40, 42 can be at least partially compensated. The synchronous machine 20 can therefore continue to be operated in this operating state, although a complete compensation for the power failure and with regard to the noise development cannot be achieved, but only a partial compensation. As a result, the synchronous machine 20 can continue to be operated even in partial power operation in the second operating state. If the problem of the inverter 40, 42 that cannot be activated occurs in the first operating state, provision can be made for the second inverters 44, 46 to be activated instead of the first inverters 40, 42.

As a result, an almost complete compensation in terms of performance and noise can be achieved. It is obvious for the person skilled in the art that this can of course be realized in reverse with regard to the inverters and the inverter modules.

Of course, the aforementioned exemplary embodiments can also be combined with one another. For this purpose, it is proposed according to a further embodiment that the drive device 10 includes a switching unit 38 (FIGS. 4, 5). The switching unit 38 can have electromechanical switching elements that provide the desired switching function, as follows will be described later. However, electronic semiconductor switching elements can also be provided, at least in part, in addition to or instead of the electromechanical switching elements.

The switching unit 38 is designed to switch the respective phase windings 32, 34 in series in a first switching state. This is shown as an example for the inverter module 50 using FIG. For this purpose, the switching unit 38 has three switching elements, which are not designated further. A respective switching element of the switching unit 38 is intended to electrically couple the respective second connection 58 of the second phase winding 34 to a central connection of a respective one of the series circuits of the respective inverters 44, 46. In FIG. 5, these two switching elements are in the off switching state. Instead, these two second connections 58 are electrically connected to one another via a third switching element and a respective inductor 62 . As a result, in each of the inverters 44, 46 only one of the half-bridge circuits or series circuits needs to be activated. This allows switching losses to be reduced.

In this embodiment, it is also provided that in the first switching state, in addition to the respective phase windings 32, 34, a respective inductor 62 is connected in series. Due to the inductance 62, a degree of freedom in relation to setting the clock frequencies of the inverters 40, 42, 44, 46 can be achieved.

In a second switching state of the switching unit 38, on the other hand, the respective first and second terminals 52, 54,

56, 58 of a respective phase winding 32, 34 coupled to the one respective inverter 40, 42, 44, 46 of a respec gene inverter module 48, 50. The winding strands 32, 34 can thus basically be driven individually. The second switching state of the switching unit 38 is shown in FIG. 4 using the inverter module 48 . The construction according to the invention makes it possible to switch the two winding strands 32, 34 in series in the partial power range of the electric drive device 10, which are connected to a respective one of the inverter modules 48, 50. As a result, an improvement in the degree of efficiency can be achieved. The additional inductance 62 also clock frequencies of the individual phases can vary almost independently of each other. This makes it possible, for example, to carry out wobbling in relation to the clock frequency, so that clock frequency components can be concealed. In particular, acoustic needles or peaks at a specific frequency can be reduced or even avoided.

The design of the internal inverter arrangement 36 also makes it possible for the electric drive device 10 to be very compact. However, during the intended ferry operation of the underwater boat 12, this can mean that a defective inverter module 48, 50 or a corresponding defective inverter 40, 42, 44, 46 can only be replaced with great effort. This is particularly difficult at sea because the electric drive device 10 should be completely switched off for the duration of the change or maintenance, as a result of which the watercraft 12 would then have no drive.

The invention makes it possible to continue driving until the next stop despite the fact that the inverter 40, 42, 44, 46 cannot be activated. However, this can degrade the acoustic properties of the drive device 10 itself. This is due to the fact that, on the one hand, the respective phase winding 32, 34, which is connected to the defective inverter 40, 42, 44, 46, can no longer be supplied with electrical current. This can lead to double and quadruple the electrical frequency of the electrical drive device 10 increasing. On the other hand, if an inverter fails in relation to the aforementioned th second aspect of the series connection in the individual circuit or the individual operation of the winding strands are switched back. However, this has the disadvantage that all inverters 40, 42, 44, 46 have to be operated at the same clock frequency, which leads to acoustically significant noise emissions, especially with regard to one or more specific frequencies, which otherwise do not occur in this speed range would.

In the case of propeller-driven watercraft in particular, the torque essentially depends on the square of the speed. This makes it possible to activate only part of the electrical drive device 10 in a lower part of the performance range of the drive device 10 . In the event of a fault in an inverter, the ferry operation can be continued with that part of the electric drive device 10 that does not include the defective inverter or the defective inverter module. As a result, acoustic deterioration can be largely avoided, but at least reduced. This is possible, for example, for a speed range from about 0% to about 35...40% of a nominal speed.

From this point, the two partial drive units are driven up to a maximum possible speed with the series connection activated, i.e. up to a speed of around 50...60% of the nominal speed. With the exception of the inverter that cannot be activated, the other inverters are operated as in the normal state. As a result, a deterioration in the acoustic signature can be reduced, if not avoided completely. In order to counteract the acoustic deterioration in the lower frequency range in relation to the increase in double and quadruple the electrical frequency, the corresponding inverter or the corresponding inverter module, which is connected to winding strands that are in the same slots as the winding strands of the non-activatable inverter are arranged, with the maximum available electrical see electricity operated. In this way, an increase in the acoustic signature in the lower speed range can be almost completely compensated for and only result in an acoustic deterioration in the upper second range.

After switching to parallel operation or individual operation of the winding strands, from a speed of around 50...60% of the nominal speed, all remaining inverters can be operated. In order to be able to counteract the acoustic deterioration in the lower frequency range, twice the current can be applied to the inverter module whose phase windings are arranged in the same slot as those of the inverter module that cannot be activated. As a result, acoustic degradation can be achieved up to about 70% of the nominal speed. Only at a higher speed can the acoustic signature deteriorate.

The exemplary embodiments serve exclusively to explain the invention and are not restrictive of it.

Claims

patent claims

1. A method for operating a drive device (10), in particular for a watercraft (12), the drive device (10) having:

- A rotating electric machine (20) having a magnetic unit (24) and a stator (22) arranged rotatably relative to the stator (22) and spaced apart from the magnetic unit (24) via an air gap (26). Rotor (28), wherein the magnetic unit (24) has grooves (30) formed on the air gap side, a first phase winding (32) being arranged in each groove (30) and a second phase winding (32) electrically insulated from the first phase winding (32). 34) is arranged, and

- An inverter arrangement (36) having a plurality of inverters (40, 42, 44, 46), a respec ger first phase winding (32) being connected to a respective first inverter (40, 42) of the inverter arrangement (36). and a respective second phase winding (34) is connected to a respective second inverter (44, 46) of the inverter arrangement (36), wherein:

- The inverters (40, 42, 44, 46) are controlled in such a way that the phase windings (30, 32) are subjected to the same predetermined electric current, characterized in that in an operating state in which one of the first inverters ( 40) cannot be activated, the respective second inverter (44) is controlled in such a way that the respective second phase winding (34) is charged with twice the specified electrical current if the specified electrical current is less than a current generated by the respective second inverter (44 ) is the maximum electric current that can be provided.

2. The method according to claim 1, characterized in that the respective second phase winding (44) is acted upon by the maximum available electrical current when the predetermined electric current is greater than the maximum current that can be provided.

3. A method for operating a drive device (10), in particular for a watercraft (12), the drive device (10) having:

- An inverter arrangement (36), which has a plurality of inverters (40, 42, 44, 46), each phase winding (32, 34) having a first connection (52, 54) being connected to an inverter (40, 42, 44, 46) is connected, where:

- in each case two first winding strands (32) of two respective slots (30) arranged directly adjacent and two second winding strands (34) of these slots (30) are connected in series via respective second connections (56, 58), and

- In a first operating state, only a predetermined selection of the inverters (40, 42) of the inverter arrangement (36) is activated, wherein in the first operating state a drive power to be provided is less than a partial power of the inverter arrangement that can be provided by the activated inverters (40, 42). (36), which is determined as a function of a maximum electric current that can be provided by the activated inverters (40, 42), and

- In a second operating state, in which the drive power to be provided is greater than the partial power, all the inverters (40, 42, 44, 46) of the inverter arrangement (36) are activated, characterized in that in the case of an inverter (40, 42) which cannot be activated and which is connected to a respective first phase winding (32), in the second operating state that inverter (44, 46) which is connected to the respective second phase winding (34) is controlled in this way that this second phase winding (34) is acted upon by the maximum electric current that can be provided.

4. The method according to claim 3, characterized in that the selection is specified such that in each slot (30) at least one phase winding (32, 34) is supplied with electric current.

5. The method as claimed in one of the preceding claims, characterized in that an inductor (52) is connected in series with a respective series connection of two phase windings (32, 34).

6. The method as claimed in one of the preceding claims, characterized in that a sound emitted by the drive device (10) is detected by means of a sound sensor and the inverters (40, 42, 44, 46) are controlled as a function of the detected sound.

7. Drive device (10), in particular for a water vehicle (12), with:

- A rotating electrical machine (20), which has a stator (22) having a magnetic unit (24) and a stator (22) which is arranged such that it can rotate and is separated from the magnetic unit (24) by an air gap (26) stationary rotor (28), the magnetic unit (24) having slots (30) formed on the air gap side, a first winding phase (32) being arranged in each slot (30) and a second winding phase electrically isolated from the first winding phase (32). (34) is arranged,

- An inverter arrangement (36) having a plurality of inverters (40, 42, 44, 46), wherein a respec ger first phase winding (32) on a respective first Inverter (40, 42) of the inverter arrangement (36) is closed and a respective second phase winding (34) is connected to a respective second inverter (44, 46) of the inverter arrangement (36), and

- A control device (68) for controlling the inverter (40, 42, 44, 46), which is designed to control the first and the second inverter (40, 42, 44, 46) in such a way that the first and the second inverter (40, 42, 44,

46) subject the respective phase windings (32, 34) to the same predeterminable electric current, characterized in that the control device (68) is also designed in an operating state in which one of the first inverters (40, 42) cannot be activated , to control the respective second inverter (44, 46) in such a way that the respective second phase winding (34) is charged with twice the predefinable electric current if the predefinable electric current is smaller than a current through the respective second inverter (44 , 46) is the maximum electric current that can be provided.

8. Drive device (10), in particular for a water vehicle (12), with:

- an inverter arrangement (36), which has a plurality of inverters (40, 42, 44, 46), each phase winding (32) having a first connection (52, 54) being connected to an inverter (40, 42, 44, 46 ) is connected, where in each case two first winding strands (32) of two respec ger directly adjacent slots (30) and each because two second phase windings (34) of these slots (30) can be connected in series via respective second connections (52, 54), and

- A control device (68) for controlling the inverter (40, 42, 44, 46), which is designed to activate only a predetermined selection of the inverters (40, 42) of the inverter arrangement (36) in a first operating state, where at in the first operating state, a drive power to be provided is less than a partial power of the inverter arrangement (36) that can be provided by the activated inverters (40, 42), which depends on a maximum electric current that can be provided by the activated inverters (40, 42). is determined, and to activate all inverters (40, 42, 44, 46) of the inverter arrangement (36) in a second operating state in which the drive power to be provided is greater than the partial power, characterized in that the control device (68) is also formed in a non-activatable inverter (40, 42), which is connected to a respective first phase winding (32), in z wide operating state that inverter (44, 46), which is connected to the respective second phase winding (34), to control such that this second winding phase (34) is charged with the maximum available electrical current rule.

9. Drive device according to claim 8, characterized in that the inverter arrangement (36) has inverter modules (48, 50), with a respective inverter module (48, 50) two of the inverters (40, 42, 44, 46) to summarizes, which are connected in parallel on the intermediate circuit side, with two series-connectable phase windings (32, 34) to the inverter (40, 42, 44, 46) of a respective inverter module (48, 50) are connected.

10. Drive device according to claim 9, characterized by a switching unit (38) which is formed in a first Switching state to switch the respective phase windings (32, 34) in series.

11. Drive device according to claim 9 or 10, characterized in that the switching unit (38) is designed, in a second switching state, the respective first and second connection (52, 54, 56, 58) of a respective phase winding

(32, 34) with a single respective inverter (40,

42, 44, 46) of a respective inverter module (48, 50).

12. Drive device according to one of claims 9 to 11, characterized in that the inverter modules (48,

50) are designed as separately manageable components, the inverter modules (48, 50) being arranged adjacent to one another in the circumferential direction within a stator opening (64) coaxial with an axis of rotation (60) of the rotor (28).

13. Drive device according to one of Claims 7 to 12, characterized in that the rotor (28) has a rotor opening (66) which is coaxial with the axis of rotation (60) and in which the inverter arrangement (36) is at least partially arranged.

14. Drive device according to one of claims 7 to 13, characterized in that the rotor (22) is designed to be permanently excited.

15. Watercraft (12) with an electric drive device (10), characterized in that the drive device (10) is designed according to one of claims 7 to 14.