WO2019025399A1

WO2019025399A1 - Electric drive device

Info

Publication number: WO2019025399A1
Application number: PCT/EP2018/070661
Authority: WO
Inventors: Stefan Koschik
Original assignee: Siemens Aktiengesellschaft
Priority date: 2017-08-03
Filing date: 2018-07-31
Publication date: 2019-02-07
Also published as: DE102017213509A1

Abstract

The invention relates to an electric drive device (2) comprising a voltage supply (4) for providing a supply voltage (UV), a three-phase machine (12) having a number of neighbouring phase windings (34, 36, 38) with a respective first and second phase ending (42, 44), as well as a modular multi-level inverter (8) connected between the voltage supply (4) and the three-phase machine (12) and having at least one sub-module series connection (20) which has at least one series-connected sub-module (24) and a filter inductor (26), and which is directed to the first phase ending (42) of an associated phase winding (34, 36, 38) of the three-phase machine (12) by means of an intermediate connection (22), wherein the second phase ending (44) of the phase winding (34, 36, 38) is coupled to the voltage supply (4) in an electrically conductive manner.

Description

description

The invention relates to an electrical or elektromotori ^¬ cal drive ^device comprising a power supply for providing a supply voltage and a three-phase machine with a number of adjacent phase windings, and a switched between the power supply and the three-phase machine modular Multilevelumrichter with at least one submodule series circuit.

Modular multilevel converters (modular multi-level converters, MMC, M2C) of the type mentioned in the beginning are frequently used as multilevel energy converters for converting a direct electrical current into an alternating current or vice versa. Such a multilevel converter typically has an AC voltage connection and a DC voltage connection for supplying and discharging the electrical energy. To the DC voltage connection here is a Teilmodulreihen ^¬ circuit as a converter circuit or as (bridge) branch or (bridge) arm connected, which has a number of individually controllable and connected in series submodules (submodules). The submodule series circuit is in this case guided to an intermediate terminal coupled to the AC voltage terminal.

An output voltage of the modular multilevel converter is in this case composed of the voltage amounts of the individual submodules. By using several Teilmodu len ^¬ thus very precise output voltages can be generated or generated. This converter topology is thus characterized in particular by high and flexible scalability, modularity and high voltage quality.

In order to reduce a current ripple, in the individual branches or partial module series circuits, in particular dere Filterinduktivitäten or filter chokes provided, which Symmetrierungsströme occurring (branch currents) zwi ^¬ rule the branches of the Multilevelumrichters filter relationship ^¬ attenuate. In this case, a substantially complete damping or filtering of the balancing ^{currents is} desired, so that the lowest possible current ^ripple is involved. As a result, comparatively large filter ^¬ inductances are required, which on the one hand the structural weight and the size of the Multilevelumrichters and on the other hand its production costs are disadvantageously increased.

Multilevel converters thus typically have a comparatively high construction weight and construction volume, as a result of which such multilevel converters are used today, in particular in stationary applications, such as in power engineering. In contrast, mobile applications, especially in the automotive or automotive sector, for example in the course of an electric or electromotive drive device, adversely affected or even made impossible. In particular, the relatively high construction ^¬ weight Multilevelumrichter typically has a negative effect on the range of an electric or electric-motor-driven motor vehicle. The invention has for its object to provide a particularly ge ^¬ suitable electric drive device.

The object is achieved with the features of claim 1. Advantageous embodiments and further developments are the subject of the dependent claims.

The electric drive ^{device according to the} invention is suitable and set up in particular for a motor vehicle operated or operable electrically or electromotively to drive one or more vehicle axles. At the ^¬ drive device here comprises a power supply for providing a supply voltage. The drive device furthermore has a multi-phase three-phase ne, for example a brushless electric motor, which is designed with a number of adjacent phase windings. The three-phase machine has in each case (motor) phase at least one phase winding, which are connected to a common rotating field winding. The phase windings are in this case designed with a first and second phase end as electrical connection areas.

Between the power supply and the three-phase machine, a modular multilevel converter is connected as a power converter. The multilevel converter here suitably has a coupled to the power supply

Gleichspannugsanschluss and one with the Drehstrommaschi ^¬ ne, in particular with the rotating field winding, coupled AC voltage connection on. To the DC voltage terminal in this case a submodule series circuit is connected as a converter circuit having at least one series-connected submodule (submodule) and a filter inductor (filter choke). The series connection of the or each submodule is guided by means of the filter inductance to an intermediate connection which is contacted to the first phase end of an associated phase winding of the three-phase machine. Suitably, the multilevel converter in this case has a number of intermediate terminals corresponding to the number of phase windings, which together form the alternating voltage connection.

The second phase end of the phase winding is according to the invention electrically conductively coupled to the power supply. In other words, a return or contact line between the second phase end and the power supply is provided. In the operation of the drive device, it is possible that between two or more sub-module series scarf ^¬ obligations electrical symmetrization currents (branch streams) th occurring which are filtered at least partly by means of the respective filter inductors. An ^unfiltered part of these balancing currents is hereby connected to the first phase end of the phase winding by means of the intermediate connection. led. By coupling the second phase end to the power supply, it is possible here to make use of the inherent leakage inductance of the (spatially) adjacent phase windings of the three-phase machine, to streams that Symmetrierungs-, or to direct the non-filtered portions to ^¬ least partially over the three-phase machine. Since ^¬ through it is possible to reduce the dimensions of the filter inductors, as this ripple does not need to dampen completeness dig the symmeterisation currents generated to suppress the current. As a result, the volume of construction and the structural weight of the filter inductors or the Multilevelumrichters thus be significantly reduced, which is transferred to the manufacturing costs of the drive device before ^¬ geous. Furthermore, thus, for example, facilitates or enables mobile applications of the drive device in electric or electric motor vehicles or aircraft. A particularly ge ^¬ suitable electric drive device is formed. Due to the multilevel converter, the three-phase ^{machine can} be operated in a normal mode in which the three-phase machine is supplied with an alternating voltage as well as in a recuperative or generator mode in which electrical energy is fed from the three-phase machine into the voltage supply. With others

Words, the multilevel converter is designed for supplying and discharging electrical energy. The power supply is in this case designed, for example, as an in-vehicle energy store or as a DC-DC converter, which rather couples the drive device to a vehicle electrical system.

The sub-modules each have an electronic module as Con troller ^¬ or control unit, which controls electric power ^¬ nik of the respective sub module. In other words, the sub-modules are individually controlled or controllable.

The multilevel converter hereby suitably has a controller as the control unit, which superordinate the Submodules of the or each sub-module series circuit controls and regulates. The controller is here generally - program and / or circuitry - set up to operate the multilevel inverter. The controller is thus concretely equipped with a regulating and / or balancing method, which is adapted to the at least partial removal or return of the balancing currents to the voltage source.

In a preferred embodiment, the controller is formed at least in the core by a microcontroller with a processor and a data memory in which the functionality for implementing the control and / or Symmetrierungsverfahrens in the form of operating software (firmware) is implemented by programming, so that the method - optionally in interaction with a vehicle user - is performed automatically when running the operating software in the microcontroller.

In the context of the invention, however, the controller may alternatively also be formed by a non-programmable electronic component, for example an ASIC, in which the functionality for carrying out the regulation and / or balancing method is implemented by means of circuit technology. In an advantageous embodiment, the second phase end is guided with the contact line to a midpoint voltage of the power supply. In a suitable development, the center point voltage in this case has a voltage potential which corresponds to half the voltage potential of the supply voltage. Thereby, a reli ^¬ particularly permeable and effective (waste) ensures guiding of the symmetrization streams.

In an expedient embodiment, the voltage supply is designed as a battery pack (battery pack, battery pack). The battery pack in this case has a series circuit ^¬ tion of a number of batteries. For example, the battery pack is here as a cell stack of Lithium ion cells formed. The midpoint voltage is in this case can be tapped at a midpoint of the battery pack in a structurally simple manner, whereby a reduction of the current ripple reliabil ^¬ SiGe is implemented.

In a preferred embodiment, the second phase ends of each phase winding are connected in a common neutral point. In other words, the phase windings in a star connection are interconnected to the rotating field winding. Suitably, the neutral point is guided by means of the contact line to the medium voltage of the power supply. As a result, a particularly expedient and low-cost ^¬ poor interconnection of the electric drive device is realized.

For the purpose of improved heat loss dissipation, the or each phase winding of the three-phase machine is cooled in a suitable design. In other words, for example, a cooling device of the three-phase machine is provided which warms or actively cools the phase windings.

In an advantageous development, the or each filter inductor is cooled. For example, it is here thinking ^¬ bar, that the filter inductances are cooled with the same Kühlvor- direction as the phase windings. By thus caused, active cooling of the filter inductors, it is possible the construction weight and size to further reduzie ^¬ ren. This is a particularly space compact and weight-reduced Multilevelumrichter realized. This translates into a result advantageous to the range of electrical ^¬ rule drive device, which is particularly advantageous in terms of (au- to-) mobile applications.

In an expedient refinement, the multilevel converter has one of the number of phase windings

Number of bridge modules, which in each case two Teilmodul ^{¬ series} circuits with a common intermediate connection respectively. This ensures a reliable and reliable operation of the three-phase machine.

Hereinafter, an embodiment of the invention is explained in detail with reference to a drawing. In it show in simplified and schematic representations:

1 shows a first embodiment of an electrical

Drive device with a voltage source and with a three-phase machine and with a dazwi ^¬ switched multilevel converter,

2 shows a bridge module of the Multilevelumrichters, and

3 shows a second embodiment of the Antriebsvor ^¬ direction.

Corresponding parts and sizes are always provided with the same reference numerals in all figures.

In FIG 1, an electric drive ^device 2 is ge ^¬ shows. The drive device 2 is, for example, for at ^¬ drove a vehicle axle an electric or motor ^¬-driven motor vehicle, for example a

Electric or hybrid vehicle, trained.

The drive device 2 has a vehicle-internal energy storage as a voltage source 4, by means of which a DC voltage as operating or supply voltage U _{v is} generated. The voltage source 4 is connected to a DC voltage connection 6 of a multilevel converter 8. The multilevel converter 8 has an AC voltage connection 10 which is routed to a three-phase three-phase machine 12 of the drive device 2.

The multilevel converter 8 has an integrated DC voltage circuit with a positive path 14 and a negative path 16, which by means of the DC voltage connection 6 to the Plus pole or the negative pole of the voltage source 4 are performed. Between the plus path 14 and the minus path 16, three bridge modules 18 are connected. The bridge modules 18 are designed as converter circuits which convert the supply voltage U _{v into} a three-phase output voltage with the phases u, v, w for the three-phase machine 12. The Bridge ^¬ ckenmodule 18 are in this case further adapted in to ^¬ ge of a recuperative or regenerative operation a fed into the AC voltage terminal 10 AC voltage to a rectified output voltage at the DC port to convert 6 to be fed to the power supply. 4

2 shows an exemplary embodiment of the bridge module 18 is shown. The bridge module 18 includes two sub-module rows ^¬ circuits 20 which Bezie ^¬ hung example are connected to the negative path 16 and a common intermedi- ate circuit 22 between the positive path fourteenth The intermediate terminal 22 is guided to the AC voltage terminal 10.

The sub-module series circuits 20 have a series connection of a number of sub-modules 24 and a filter inductance 26. In FIG. 2, only three submodules 24 of submodule series circuits 20 are shown by way of example.

The sub-modules 24 each have a module electronics 28 and a power electronics 30 and an energy storage 32, which are shown only schematically in FIG 2 and provided with reference numerals by way of example. In this case, the module electronics 28 is designed as a controller or control unit for controlling and / or regulating the respective power electronics 30. The power electronics 30 is embodied, for example, as a half-bridge or full-bridge circuit and has a number of power semiconductor switches, for example IGBTs (insulated gate bipolar transistor), which can be switched from a conducting to a non-conducting state by means of the power electronics 30. The energy storage 32 is in this case as a capacitor or capacitor executed, which is loaded upon activation of the Leistungselekt ^¬ ronik 30 with electrical energy.

Between the energy storage 32 of the sub-modules 24 symmetrizing electrical ^¬ ungsströme I _s, which of the generated from ^¬ transient current or of the phases u, v, w causes a ripple current to flow during operation of the Multilevelumrichters. 8 For suppressing and reducing the balancing currents I _s , the filter inductances 26 are provided. The filter inductances 26 are in this case dimensioned such that the

Symmetrizing currents I _{s are} at least partially filtered, with a remaining, not filtered residual portion of the balancing currents I _s ^x to the AC voltage terminal 10, and thus the three-phase machine 12 is performed.

The three-phase machine 12 is designed as a three-phase, brushless ^¬ electric motor. As (motor) phases u, v, w, the three-phase machine 12 in this case-as can be seen in particular in FIG. 3-has three phase windings 34, 36, 38 which are connected as a star connection to a rotating field winding 40.

The phase windings 34, 36 and 38 each have a first phase end 42, which is guided to the AC voltage terminal 10 of the Multilevelumrichters 8, and a second Pha ^¬ senende 44, which is connected in a common neutral point 46 of the rotating field winding 40 on. By way of example, in FIG. 3 only the phase winding 34 is provided with reference symbols for the phase ends 42 and 44.

In the embodiment of FIG 3, the Teilmodulrei ^¬ henschaltungen 20 of the bridge modules 18 each have only a single sub-module 24th The star point 46 is contacted by means of a contact line 48 with the voltage source 4. It is conceivable, for example, that the contact line 48 in the

Multilevel converter 8 is integrated, or as a separate, ex- Terne line is guided by the three-phase machine 12 to Spannungsquel ^¬ le 4. In the embodiment of FIG. 3, the voltage source 4 is designed as a battery pack (battery pack) with two series-connected batteries 50a and 50b. The contact line 48 is in this case connected at a midpoint between the two batteries 50a and 50b, so that the star point 46 is guided to a center point voltage U _{M of} the voltage source 4. Due to the electrically conductive coupling between the star point 46 and the midpoint voltage U _M to the voltage source 4, it is possible that occurs during operation of the rotating field winding 40 leakage inductance of the alternator 12 to nut ^¬ zen to the non-filtered symmetrization currents I _s ^x about the rotary electric machine 12 to conduct. This makes it possible to dimension the filter inductances 26 smaller.

In an additional or alternative embodiment, it is conceivable, for example, that the phase windings 34, 36, 38 and / or the filter inductances 26 are actively cooled in order to improve a heat loss dissipation of the balancing currents I _s , Is ^x .

The invention is not limited to the exemplary embodiments described above. Rather, other Vari ^¬ distinctive of the invention by those skilled in the therefrom derived, without departing from the scope of the invention. In particular, all the individual features described in connection with the exemplary embodiments can also be combined with one another in other ways, without departing from the subject matter of the invention.

Claims

claims

1. Electric drive device (2) comprising

a voltage supply (4) for providing a supply voltage (U _v ),

- A three-phase machine (12) having a number of be ^¬ adjacent phase windings (34, 36, 38) each having a first and second phase end (42, 44), and

- one between the power supply (4) and the

Three-phase machine (12) switched modular

Multilevelumrichter (8) with at least one part module ^¬ series circuit (20) comprising at least one series-connected sub-module (24) and a filter inductor

(26), and which by means of an intermediate terminal (22) to the first phase end (42) of a ^¬ orderly phase winding (34, 36, 38) of the three-phase machine (12) is guided, wherein the second phase end

(44) of the phase winding (34, 36, 38) is electrically conductively coupled to the power supply (4).

2. Drive device (2) according to claim 1,

characterized in that the second phase end (44) with a contact line (48) to a midpoint voltage (UM) of the power supply (4) is guided.

3. Drive device (2) according to claim 2,

characterized in that the midpoint voltage (UM) comprises a voltage potential corresponding to the half of the tension ^¬ voltage potential of the supply voltage (Uv).

4. Drive device (2) according to one of claims 1 to 3, characterized in that the power supply (4) as a battery pack with a number of series-connected batteries (50a, 50b) is executed.

5. Drive device (2) according to one of claims 1 to 4, characterized in that the second phase ends (44) of the phase windings (34, 36, 38) in a common neutral point (46) are connected. 6. Drive device (2) according to one of claims 1 to 5, characterized in that the or each phase winding (34, 36, 38) is cooled.

7. Drive device (2) according to one of claims 1 to 6, characterized in that the or each filter inductance

(26) is cooled.

8. Drive device (2) according to one of claims 1 to 7, characterized in that the Multilevelumrichter (8) has one of the number of phase windings (34, 36, 38) of the three-phase machine (12) corresponding number of bridge modules (18) which each having two sub-module series circuit (20) with a common intermediate connection (22).