Accident-proof power electronics unit, drive device having the power electronics unit and correspondingly equipped motor vehicle

Abstract

The present invention relates to a power electronics unit (10) comprising: a power semiconductor (18) for providing an alternating current voltage; external contacts (26) for electrically connecting a stator winding of a permanent magnet synchronous motor (44) to which an alternating current voltage is to be supplied; and a filter circuit (30) spatially spaced apart from the power semiconductor (18). The filter circuit (30) is electrically connected between the power semiconductor and the external contacts (26). A pyrotechnic separation unit (34) is integrated in the filter circuit (30), which is configured to physically sever the electrical connection between the power semiconductor (18) and the external contacts (26) extending through the filter circuit (30) and the separation unit (34) within the separation unit (34). The present invention also relates to a drive device (42) having such a power electronics unit (10) and a motor vehicle (40) having such a drive device (42).

Description

Technical Field

[0001] This invention relates to a power electronics unit for a permanent magnet synchronous motor and a drive device having such a power electronics unit. The invention also relates to a motor vehicle having such a drive device. Background Technology

[0002] Electric motors are used in many different applications and fields, such as increasingly as drive mechanisms for electric vehicles. Particularly in permanent magnet synchronous motors, rotor motion induced on the non-drive side (i.e., not caused by the synchronous motor itself and therefore uncontrolled) can induce unwanted currents, i.e., unwanted electrical currents, based on the permanent magnets. To avoid this, a conventional switch can be disconnected to cut off the corresponding current path, for example. However, in some cases, this may not be feasible or fast enough. Therefore, fuses may be used, for example, or additionally. However, once a fuse is triggered, repairs can be time-consuming and / or costly, and may itself pose a risk of further damage to other components.

[0003] For example, EP 3 542 437 B1 describes a protective device for a vehicle with high-voltage and high-current components. This document proposes that, in addition to physically isolating the battery from the high-voltage intermediate circuit, a discharge resistor is used to discharge the high-voltage intermediate circuit. This should improve safety, especially during a collision.

[0004] WO 2017 / 101 996 A1 describes a power electronics unit for controlling a permanent magnet excitation motor, the motor including a rotor and a stator with stator windings. An overvoltage protection device is provided to protect the power switch used to control the stator windings. This protection device includes a phase voltage detection device assigned to the power switch and a short-circuit switch that can be activated to short-circuit the stator windings when a predetermined phase voltage threshold is reached or exceeded. Therefore, it is intended to provide a protection device for voltage feedback effects in permanent magnet excitation motors that is technically simpler in circuitry, particularly suitable for situations where the motor operates under weak field conditions.

[0005] However, these existing methods cannot solve all the problems, so improvements to the corresponding electrical and / or electronic systems are still needed. Summary of the Invention

[0006] The objective of this invention is to achieve safe operation of electric vehicles and particularly simple, efficient and safe maintainability.

[0007] This task is solved by the technical solution of the independent claim. Other possible designs of the invention are disclosed in the dependent claims, the specification, and the drawings. The features, advantages, and possible designs set forth within the scope of the specification for one of the technical solutions of the independent claim can be at least similarly regarded as the features, advantages, and possible designs of the corresponding technical solutions of other independent claims and any possible combinations of the technical solutions of the independent claims, and, if necessary, combined with one or more dependent claims.

[0008] The power electronic unit according to the invention is specified, i.e., correspondingly configured and designed for powering a permanent magnet synchronous motor (PSM). The power electronic unit has power semiconductors, or power semiconductor switches, for providing an AC voltage on the output side, particularly for converting a DC voltage applied on the input side into an AC voltage on the output side. Furthermore, the power electronic unit has electrical external contacts for electrically connecting the stator windings of the corresponding PSM to which AC voltage is to be supplied via said external contacts. Thus, the electrical connection within the power electronic unit can extend from the power semiconductor to the external contacts. In addition, the power electronic unit includes a filter circuit for filtering the AC voltage or the AC current correspondingly flowing through the external contacts during operation. The filter circuit is spatially spaced from the power semiconductor and electrically connected between the power semiconductor and the external contacts.

[0009] According to the invention, the power electronics unit further includes a pyrotechnic disconnect unit or disconnect device disposed in or integrated into the filter circuit. The disconnect unit is configured and arranged to physically sever the electrical connection extending through the filter circuit and the disconnect unit between the external contacts and the power semiconductor. For this purpose, upon triggering of the disconnect unit, for example by gas pressure, a piston or disconnect element is suddenly accelerated, thereby completely severing the corresponding electrical conductor, such as a cable, busbar, or the like. In particular, the free ends of the electrical conductors thus created are electrically insulated from each other by the piston or disconnect element. The pyrotechnic disconnect unit can very quickly and reliably interrupt the electrical connection between the external contacts and the power semiconductor, and therefore can also interrupt the electrical connection between the power semiconductor and the corresponding PSM or its stator when the power electronics unit is used as intended. However, this interruption is not reversible like that of a conventional switch. Therefore, to re-establish the electrical connection, for example, the disconnect unit must be replaced.

[0010] In existing electric drive systems, AC or DC disconnect switches can be directly integrated into the inverter's electronics or the battery controller, for example. This may result in the inverter or battery controller having to be fully opened for repairs in the event of a fault or after a fault occurs, which can be very complex and carries the risk of damaging surrounding highly sensitive components or electronic parts.

[0011] This invention provides at least a partial remedy in this regard. By placing the separation unit within or on the filter circuit, the separation unit is spatially separated from typically particularly sensitive electronic components (e.g., power semiconductors). Conversely, the filter circuit can be constructed, for example, as a relatively robust, i.e., less sensitive electrical circuit, especially a discrete circuit. This reduces the risk of secondary damage during maintenance (e.g., when replacing the separation unit). Even if damage occurs, it can be repaired at a lower cost if necessary, since the filter circuit typically contains only relatively inexpensive and / or individually replaceable electrical components. Overall, the proposed placement of the separation unit outside or spaced apart from particularly sensitive electronic components provides better protection for the rest of the power electronics unit and / or, in the case of the application, other components of the electrical system in which the power electronics unit is embedded.

[0012] In one possible design of the invention, the separation unit is or constitutes a separate integral component; in other words, the separation unit can operate separately from the rest of the power electronics unit as a discrete component or unit. Therefore, the separation device can be installed into or removed from the power electronics unit particularly easily, for example. Thus, the separation unit can be replaced simply and quickly.

[0013] In one possible extension of the invention, the separation unit is detachably and reversibly fixed to the filter circuit or the remainder of the filter circuit in a non-destructive and reversible manner. For example, the separation unit can be fixed to the carrier or bus of the filter circuit. In particular, the separation unit can be fixed by means of one or more threaded connections. Therefore, the separation unit can be easily and quickly replaced, for example, after triggering, without damaging or harming the filter circuit or the rest of the power electronics unit. To restore the power electronics unit to a fully operational ready state after the separation unit is triggered, the separation unit can be replaced individually without replacing the entire power electronics unit. Furthermore, the risk of damaging other components of the power electronics unit when replacing the separation unit is kept particularly low. The threaded connection, i.e., fixing the separation unit by means of one or more screws, also allows replacement using widely available and relatively simple and error-resistant tools. Therefore, for example, no special tools are required to replace the separation unit, thus the replacement of the separation unit can be achieved at low cost and, if necessary, at least almost location-independently.

[0014] In another possible design of the invention, the power electronics unit has a housing that houses the filter circuitry and power semiconductors. The housing itself has an opening that is removably covered in a non-destructive and reversible manner by means of a covering element. This covering element can be, for example, a cover, a flap, or the like. When the covering element is opened or removed, the filter circuitry can be accessed through the opening to replace the separation unit, while the power semiconductors are covered or remain covered by another area of ​​the housing (e.g., adjacent to the opening). In other words, the area of ​​the opening at least primarily or only covers the filter circuitry or a portion thereof, but not the power semiconductors. The opening or covering element can therefore be specifically used as a maintenance or repair access point for the separation unit or its replacement. Since the power semiconductors (and other components of the power electronics unit that may be located around the power semiconductors and / or the filter circuitry) are still covered by the housing or one side of the housing (i.e., the side where the opening is located) even when the covering element is opened or removed, the risk of damage to the power semiconductors or, where possible, other surrounding components during the replacement of the separation unit is minimized. This allows for a particularly simple, low-cost, and safe replacement of the separation unit. This can be beneficial for safety and cost-effectiveness and is particularly resource-efficient.

[0015] In one possible extension of the invention, the cover element is secured to the housing by one or more threaded connections, i.e., by one or more screws. In particular, the cover element can be secured to the housing solely by this threaded connection or these threaded connections. For example, the corresponding threads can be located adjacent to or around the opening in the housing. With the extension proposed herein, the cover element can be removed particularly easily and (e.g., after replacing the separation unit) then re-secured to the housing. Furthermore, the cover element can be reliably and securely held to the housing.

[0016] In one possible extension of the invention, a seal surrounding the opening is provided between the housing and the cover element. This seals the opening or the interior space of the housing relative to the environment, preventing dust, dirt, and / or moisture from entering the power electronics unit. Therefore, the power electronics unit can operate safely and reliably even under potentially harsh environmental conditions, despite easy access to the separation device. The seal can be, for example, a planar seal, a profile seal, a lip seal, or the like. In particular, the seal can be implemented using discrete sealing components, such as rubber rings or the like. This contrasts sharply with sealant, for example. Thus, sealing is maintained even with repeated opening, removal, and reinstallation of the cover element, and the cost of replacing the separation unit remains low.

[0017] The present invention also relates to a drive unit, which is particularly intended or designed for use in motor vehicles. The drive unit according to the invention comprises a power electronics unit according to the invention, a permanent magnet synchronous motor electrically connected to external contacts of the power electronics unit, and a control circuit or controller. The control circuit or controller is configured to automatically trigger a disconnection unit in response to a predefined accident signal to disconnect the electrical connection between the external contacts and the power semiconductor. Such an accident signal may, for example, be an electrical or electronic signal from an accident sensor, which may be received by the controller via a corresponding interface or wire. Similarly, the controller itself may, for example, include an accident sensor configured to identify (e.g., an accident in a motor vehicle equipped with the drive unit). Likewise, if necessary, the accident sensor itself may constitute the control circuit, so that the sensor signal emitted by the accident sensor upon detecting an accident can directly trigger the disconnection unit. The control circuit or controller may be a separate component or integrated into or combined with other components and / or functions. For example, the control circuit or controller may be integrated into the power electronics unit or combined with a control device for a synchronous motor.

[0018] The present invention also relates to a motor vehicle comprising a drive unit according to the invention and a high-voltage memory, i.e., a high-voltage secondary battery. The high-voltage memory is connected to the input terminal, i.e., the electrical input terminal, of the power electronics unit of the drive unit and configured to provide DC voltage to the power electronics unit via this input terminal. In other words, the drive unit can be powered by the high-voltage memory. Similarly, the generator operating mode of the drive unit can be used to charge the high-voltage memory. The motor vehicle may also include, in particular, an accident sensor for generating an accident signal in conjunction with the drive unit of the invention when an accident is detected, the accident sensor being either a separate component connected to the drive unit or as part of the drive unit. The motor vehicle according to the invention is particularly likely the motor vehicle mentioned in conjunction with the power electronics unit and / or the drive unit of the invention.

[0019] Other features of the invention can be derived from the claims, drawings, and description of the drawings. The features and combinations thereof mentioned above in the specification, as well as the features and combinations thereof shown separately in the description of the drawings and / or the drawings below, may be used not only in the given combinations, but also in other combinations or alone, without departing from the scope of the invention. Attached Figure Description

[0020] Figure 1 A partial schematic perspective view of a power electronics unit is shown, with the maintenance cover closed;

[0021] Figure 2 A partial schematic perspective view of the power electronics unit is shown, with the maintenance cover open;

[0022] Figure 3 A partial schematic perspective view of the filter circuit of the power electronics unit is shown, which includes an integrated pyrotechnic separation unit.

[0023] Figure 4 A partial schematic perspective view of the power electronics unit is shown, in which the maintenance cover is open and the pyrotechnic separation unit has been removed for replacement;

[0024] Figure 5 A partial schematic diagram of a motor vehicle having this power electronics unit is shown. Detailed Implementation

[0025] In the accompanying drawings, identical and identical elements are denoted by the same reference numerals. For clarity, in the accompanying drawings, for at least some of the multiple identical or similar elements, only a representative selection is explicitly labeled.

[0026] Figure 1 A partial schematic perspective view of a power electronics unit 10 with a housing 12, in which various electrical and electronic components are housed, is shown. The housing 12 includes a lower housing portion 14 and an upper housing portion 16, which are connected to each other and form or enclose the internal space of the housing 12. Components assigned to different functions of the power electronics unit 10 can be arranged in different regions or groups. In this case, the housing 12 may have, for example, corresponding spatially spaced shaped portions for enclosing or accommodating these regions or groups of components. For example, the power electronics unit 10 or housing 12 has an electronics region 18 and a filter region 20. In the electronics region 18, for example, power semiconductors for converting the DC voltage on the input side to the AC voltage on the output side can be provided. In the filter region 20, a filter circuit 30 for filtering the AC voltage or corresponding AC current can be housed (see...). Figure 2 ).

[0027] The housing 12 here includes a maintenance cover 22 that serves as a cover for the filter region 20. The maintenance cover 22 is connected to the rest of the upper housing 16 at a fixing point 24, for example by a threaded connection. Thus, the maintenance cover 22 can be removed from the rest of the upper housing 16 to allow access to the components located below it, namely the power electronics unit 10, which are disposed in the filter region 20.

[0028] The power electronics unit 10 has a plurality of external electrical contacts 26 on the output side. These external contacts 26 can be electrically connected to a filter circuit 30 and, through which, to a power semiconductor. Therefore, a filtered AC voltage can be provided at the external contacts 26. In the prescribed use of the power electronics unit 10, for example in a motor vehicle 40 (see...), Figure 5In this context, external contact 26 can be connected, for example, to a permanent magnet synchronous motor, namely PSM 44 (see...). Figure 5 On the stator winding of ).

[0029] To protect the PSM 44 in the event of an accident involving the motor vehicle 40, the stator of the PSM 44 should be electrically isolated from the power supply inverter, and in particular from the power semiconductors of the power electronics unit 10. This is because, for example, when the motor vehicle 40 is coasting or towing after an accident, the permanent magnets of the PSM 44 may generate undesirable electrical currents. However, in such cases, replacing the entire power electronics unit 10 should be avoided as much as possible, and repairs should be performed as simply, quickly, and safely as possible.

[0030] To illustrate the solutions to these challenges, Figure 2 A partial schematic diagram of the power electronics unit 10 is shown, with the maintenance cover 22 open or removed. Therefore, a maintenance opening 28, which can be covered by the maintenance cover 22, is exposed in the housing 12 or the upper housing 16. Correspondingly, the filter circuitry 30 is partially visible here, i.e., accessible through the maintenance opening 28. However, even with the maintenance cover 22 open or removed, the power semiconductors in the electronics region 18 remain covered by the upper housing 16.

[0031] The filter circuit 30 is electrically connected to external contacts 26 on the output side, and can also be connected to internal electrical contacts 32 on the input side. These internal contacts 32 can form electrical connections with power semiconductors in the electronics region 18 and / or with other and / or other components of the power electronics unit 10.

[0032] To separate the PSM 44 from the power semiconductor of the power electronics unit 10 in the event of an accident (i.e., in the event of a collision), the power electronics unit 10 includes a pyrotechnic separator, namely a pyrotechnic separator unit 34. This separator unit 34 is integrated into or fixed to the filter circuit 30. Currently, the separator unit 34 is fixed to the filter circuit 30 or the rest of the filter circuit 30 as a separate component by means of screws 36. Therefore, when the maintenance cover 22 is opened or removed, these screws 36 can be loosened to remove the separator unit 34. Accordingly, a new separator unit 34 can then be installed and secured again with screws 36. Afterwards, the maintenance cover 22 can be reattached to the maintenance opening 28 and secured to the upper part 16 of the housing to reseal the maintenance opening 28.

[0033] To further illustrate, Figure 3A schematic perspective view of a filter circuit 30 is shown, which has external contacts 26, internal contacts 32, and a disconnect unit 34. A control contact plug 38, connected to the disconnect unit 34, is also visible here. This control contact plug 38 can be connected to a control circuit or controller, or, for example, directly to an accident sensor. A signal for triggering the disconnect unit 34 can be sent to the disconnect unit via the appropriate connection or control contact plug 38. Upon such triggering, the disconnect unit 34 can then interrupt or disconnect the electrical connection between the power semiconductor and the external contacts 26. To replace the disconnect unit 34, in addition to loosening the screws 36, the control contact plug 38 can be unplugged from the disconnect unit 34 and plugged back in at a later date.

[0034] To further illustrate, Figure 4 A partial schematic diagram of the power electronics unit 10 is shown, in which the maintenance cover 22 has been opened or removed and the separation unit 34 has been removed.

[0035] Figure 5 A partial schematic diagram of a motor vehicle 40 is shown. The motor vehicle 40 has a drive unit 42, which includes a PSM 44 and a power electronics unit 10. To supply power to the drive unit 42, the motor vehicle 40 also has a high-voltage memory 46. This high-voltage memory can be electrically connected to the power electronics unit 10 on its input side, particularly to the input of a power semiconductor located in the electronics region 18, or a corresponding power semiconductor module or inverter module.

[0036] In summary, the described examples demonstrate how to integrate pyrotechnic separation elements into AC filters within electric motors in order to improve protection for the rest of the inverter and achieve ease of maintenance through this arrangement, which places the components outside of sensitive electronic parts.

[0037] List of reference numerals

[0038] 10 power electronics units

[0039] 12 shells

[0040] 14 Lower part of the shell

[0041] 16 Upper part of the shell

[0042] 18 Electronic Components Area

[0043] 20 filter region

[0044] 22 Maintenance Cover

[0045] 24 fixed points

[0046] 26 external contacts

[0047] 28 maintenance openings

[0048] 30 filter circuit

[0049] 32 internal contacts

[0050] 34 separation units

[0051] 36 screws

[0052] 38 control contact plug

[0053] 40 motor vehicles

[0054] 42 drive unit

[0055] 44PSM

[0056] 46 High-voltage memory

Claims

1. A power electronics unit (10) for a permanent magnet synchronous motor (44), the power electronics unit comprising: Power semiconductors (18) used to provide AC voltage; External contacts (26) are used to electrically connect the stator windings of the corresponding permanent magnet synchronous motor (44) to which AC voltage is to be supplied via the external contacts (26); A filter circuit (30) is spatially spaced from the power semiconductor (18) and electrically connected between the power semiconductor and the external contact (26) for filtering AC voltage; and A pyrotechnic separation unit (34) is integrated into the filter circuit (30) and configured to physically sever the electrical connection between the power semiconductor (18) and the external contact (26) extending through the filter circuit (30) and the separation unit (34) within the separation unit (34).

2. The power electronic unit (10) according to claim 1, characterized in that, The separation unit (34) constitutes an independent integral component.

3. The power electronic unit (10) according to any one of the preceding claims, characterized in that, The separation unit (34) is detachably fixed to the filter circuit (30) in a non-destructive and reversible manner, especially by means of one or more threaded connections (36).

4. A power electronics unit (10), characterized in that, The power electronics unit (10) has a housing (12, 14, 16) in which a filter circuit (30) and a power semiconductor are housed, and the housing (12, 16) has an opening (28) which is covered by a cover element (22) that is removable in a non-destructive and reversible manner and allows access to the filter circuit (30) to replace the separation unit (34) if the cover element (22) is removed, while the power semiconductor (18) is still covered by another area (16) of the housing (12, 16).

5. The power electronics unit (10) according to claim 4, characterized in that, The covering element (22) is fixed to the housing (12, 16) by means of one or more threaded connections, especially by means of only one or more threaded connections (24).

6. The power electronics unit (10) according to claim 4 or 5, characterized in that, A seal is provided between the housing (12, 16) and the covering element (22) to surround the opening (28).

7. A drive unit (42) comprising a power electronics unit (10) according to any of the preceding claims, a permanent magnet synchronous motor (44) electrically connected to an external contact (26) of the power electronics unit, and a controller configured to automatically trigger a separation unit (34) in response to a predefined fault signal.

8. A motor vehicle (40) comprising a drive unit (42) according to claim 7 and a high-voltage memory (46) for providing a DC voltage to the input terminal of the power electronics unit (10) of the drive unit (42).

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