Traction network and filter unit

Abstract

The invention relates to a traction network (1) of an electric or hybrid vehicle, comprising a DC voltage source (2), at least one intermediate circuit capacitor (7), an inverter (3), and a separately excited synchronous machine (4), wherein a first EMC filter (9) is arranged between the inverter (3) and the DC voltage source (2), wherein power electronics (8) are provided which are configured to generate a rotor current for rotor windings (6) of the separately excited synchronous machine (4), wherein a further EMC filter (10) is arranged between the power electronics (8) and the rotor windings (6), and an AC filter (11) is arranged between the inverter (3) and stator windings (5) of the separately excited synchronous machine (4), wherein the first EMC filter (9), the further EMC filter (10), and the AC filter (11) are arranged as a filter unit (12) in a common housing (13) and / or on a common printed circuit board (14). are,as well as a filter unit (12).,

Description

[0001] The invention relates to a traction network for an electric or hybrid vehicle and a filter unit.

[0002] Traction systems for electric and hybrid vehicles consist of a DC power supply, at least one intermediate circuit capacitor, an inverter, and an electric motor. The DC power supply is usually a high-voltage battery. The inverters are typically pulse-width modulated (PWM) inverters, which can be configured as two- or three-level pulse inverters. The electric motor can be either asynchronous or synchronous. Synchronous motors can be separately excited or permanent magnet synchronous. The advantage of separately excited synchronous motors is that the rotor field can be switched off, eliminating the need for rare earth elements, although the rotor current must still be supplied.

[0003] Especially when using pulse-width modulation (PWM) inverters, the rapid, steep switching edges generate interference radiation. This problem is exacerbated if the high-voltage lines between the high-voltage battery and the PWM inverter are unshielded, as they then act like an antenna. Furthermore, this RF interference is damaging to many components. Therefore, it is common practice to use EMC filters to minimize RF interference. Various types of EMC filters are available. For example, there are active and passive EMC filters, which can also be used in combination. One such combination is described in German patent application DE 10 2017 223 763 A1.

[0004] One proposed design is a passive EMC filter with two ferrite rings through which the high-voltage lines are routed, or which are wound around the ferrite rings in opposite directions. Y-capacitors are arranged between the two ferrite rings, connected to ground.

[0005] Another configuration involves an X-capacitor on the high-voltage battery side, a common-mode choke followed by two Y-capacitors and another X-capacitor. Concepts are also known that additionally incorporate ohmic resistors.

[0006] The pulse inverter not only generates RF interference on the DC side but also on the AC side of the electric machine, so it is also known to use EMC filters (AC filters) on the AC side.

[0007] From CN 111 44 ​​69 02 A an EMC filter is known which integrates an EMC filter on the DC voltage side and an EMC filter on the AC voltage side in a common housing.

[0008] When using separately excited synchronous machines, additional power electronics are required to provide the rotor current. Here, too, it has already been proposed to use an EMC filter between the rotor winding and the power electronics.

[0009] The invention is based on the technical problem of improving the compactness of a traction network with a separately excited synchronous machine and creating a corresponding filter unit.

[0010] The solution to the technical problem is achieved by a traction network with the features of claim 1 and a filter unit with the features of claim 6. Further advantageous embodiments of the invention are set forth in the dependent claims.

[0011] The traction network of an electric or hybrid vehicle comprises a DC voltage source, at least one intermediate circuit capacitor, an inverter, and a separately excited synchronous machine, wherein a first EMC filter is arranged between the inverter and the DC voltage source. The DC voltage source is preferably a high-voltage battery, and the inverter is preferably a pulse-width modulated (PWM) inverter. Furthermore, power electronics are provided, configured to generate a rotor current for the rotor windings of the separately excited synchronous machine, wherein a further EMC filter is arranged between the power electronics and the rotor windings.

[0012] An AC filter is located between the inverter and the stator windings of the separately excited synchronous machine. This AC filter also functions as an EMC filter. The term "AC filter" serves to better distinguish the filters, as the first and subsequent EMC filters function as DC EMC filters. The first EMC filter, the subsequent EMC filter, and the AC filter are integrated as a filter unit in a common housing and / or on a shared circuit board. This offers numerous advantages over separate designs for all three filters. For example, the filter unit requires less installation space, only one housing (saving material), and / or only one circuit board. Furthermore, a common cooling system can be implemented.

[0013] In one embodiment, the outputs of the three filters are arranged on a common side of the housing and / or the circuit board, thus simplifying the common integration and the routing of cables.

[0014] In another embodiment, at least two of the three filters have a common component, so that the number of components can also be reduced.

[0015] In one embodiment, the shared component is at least one soft magnetic core. This soft magnetic core can also be used by all three filters.

[0016] The soft magnetic core can, for example, consist of a nanocrystalline material or be designed as a ferrite ring.

[0017] In another embodiment, at least the inputs of the first EMC filter and the further EMC filter are arranged on a common side of the housing and / or the circuit board.

[0018] Regarding the design of the filter unit, full reference is made to the preceding statements.

[0019] The invention is explained in more detail below with reference to preferred embodiments. The figures show: Fig. 1 a schematic block diagram of a traction network, Fig. 2 a schematic representation of a printed circuit board of a filter unit, Fig. 3 a schematic representation of a traction network with a separately excited synchronous machine (state of the art) and Fig. 4 a block diagram of a traction network according to Fig. 3 (State of the art).

[0020] In the Fig. Figure 3 schematically depicts a traction network 1 of an electric or hybrid vehicle. The traction network 1 comprises a DC voltage source 2, an inverter 3, and a separately excited synchronous machine 4 with stator windings 5 ​​and rotor windings 6. The DC voltage source 2 is preferably a high-voltage battery, and the inverter is preferably a pulse-width modulated (PWM) inverter. Furthermore, the traction network 1 includes at least one DC link capacitor 7 and power electronics 8. The power electronics 8 generates a rotor current for the rotor windings 6 of the separately excited synchronous machine. The DC link capacitor 7 is located between the DC voltage source 2 and the inverter 3. A first EMC filter 9 is arranged between the inverter 3 and the DC voltage source 2. This filter has two first inputs E1 that are connected to the inverter 3.Furthermore, the first EMC filter 9 has two first outputs A1, which are connected to the DC voltage source 2. The traction network 1 also has another EMC filter 10, which has two second inputs E2, which are connected to the power electronics 8. Two second outputs A2 of the further EMC filter 10 are connected to the rotor windings 6. Finally, the traction network 1 has an AC filter 11, which has three third inputs E3 and three third outputs A3 and is arranged between the inverter 3 and the stator windings 5. The AC filter 11 is, for example, designed as a ferrite ring through which phase lines are passed.

[0021] In the Fig. 4 is the traction network 1 according to Fig. 3 is shown redrawn.

[0022] In the Fig. Figure 1 shows the traction network 1 according to the invention, wherein the three separate filters, i.e., the first EMC filter 9, the further EMC filter 10, and the AC filter 11, are arranged in a filter unit 12 with a common housing 13. All outputs A1-A3 of the three filters 9-11 are arranged on one side of the housing 13. The inputs E1-E3 of all three filters 9-11 are also arranged on a common side of the housing 13. To keep the housing as small and compact as possible, it is also possible for the inputs E1 of the first EMC filter 9 to be routed on another side of the housing 13 in the filter unit 12.

[0023] In the Fig.Figure 2 is a highly simplified representation of the filter unit 12, where the elements of the three filters 9-11 are arranged on a common circuit board 14, with all inputs E1-E3 and all outputs A1-A3 located on the same side. The first EMC filter 9 has an X-capacitor C at each of the inputs E1 and outputs A1. X1 which can be of different dimensions. Furthermore, the first EMC filter 9 has two Y-capacitors C. Y1 on, which are connected to ground. Between the X capacitors C X1 A common-mode choke 15 is arranged, which has a soft magnetic core 16. Accordingly, the further EMC filter 10 has two X-capacitors C. X2 , two Y-capacitors C Y2and a common-mode choke 17, wherein the two common-mode chokes 15, 17 utilize the common soft magnetic core 16. The EMC filters 9, 10 can also have and utilize multiple soft magnetic cores 16. Likewise, the connecting lines between the third inputs E3 and the third outputs of the AC filter 11 are guided through a soft magnetic core 16. This can be the same soft magnetic core 16 as for the EMC filters 9, 10, or a separate soft magnetic core 16. Preferably, the common soft magnetic core 16 is oval-shaped and, for example, configured as a ferrite ring. Reference symbol list 1 Traction network 2 DC voltage source 3 inverters 4 separately excited synchronous machines 5 Stator winding 6 Rotor winding 7 Intermediate circuit capacitor 8 Power Electronics 9 first EMC filter 10 more EMC filters 11 AS filters 12 filter units 13 cases 14 circuit board 15 Common-mode choke 16 soft magnetic core 17 Common-mode choke A1-A3 Exits E1-E3 Inputs C X1 , C X2 X-capacitor C Y1 , C Y2 Y-capacitor QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2017 223 763 A1

[0003] CN 111 44 ​​69 02 A

[0007]

Claims

Traction network (1) of an electric or hybrid vehicle, comprising a DC voltage source (2), at least one intermediate circuit capacitor (7), an inverter (3) and a separately excited synchronous machine (4), wherein a first EMC filter (9) is arranged between the inverter (3) and the DC voltage source (2), wherein power electronics (8) are provided which are configured to generate a rotor current for rotor windings (6) of the separately excited synchronous machine (4), wherein a further EMC filter (10) is arranged between the power electronics (8) and the rotor windings (6) and an AC filter (11) is arranged between the inverter (3) and stator windings (5) of the separately excited synchronous machine (4), wherein the first EMC filter (9), the further EMC filter (10) and the AC filter (11) are arranged as a filter unit (12) in a common housing (13) and / or on a common printed circuit board (14). Traction network according to claim 1, characterized in that the outputs (A1-A3) of the three filters (9-11) are arranged on a common side of the housing (13) and / or the circuit board (14). Traction network according to claim 1 or 2, characterized in that at least two of the three filters (9-11) have a common component. Traction network according to claim 3, characterized in that the at least one shared component is at least one soft magnetic core (16). Traction network according to one of the preceding claims, characterized in that at least the inputs (E1, E2) of the first EMC filter (9) and of the further EMC filter (10) are arranged on a common side of the housing (13) and / or the circuit board (14). Filter unit (12), wherein the filter unit (12) comprises a first EMC filter (9) having two first inputs (E1) for a first interference source and two first outputs (A1), a further EMC filter (10) having two further inputs (E2) for a second interference source and two outputs (A2), and an AC filter (11) having at least one third input (E3) for a third interference source and at least one third output (A3), wherein the three filters (9-11) are arranged in a common housing (13) and / or on a common printed circuit board (14). Filter unit according to claim 6, characterized in that the three filters (9-11) are arranged on a common side of the housing (13) and / or the circuit board (14). Filter unit according to claim 6 or 7, characterized in that at least two of the three filters (9-11) have a common component. Filter unit according to claim 8, characterized in that the at least one common component is at least one soft magnetic core (16). Filter unit according to one of claims 6 to 9, characterized in that at least the inputs (E1, E2) of the first EMC filter (9) and of the further EMC filter (10) are arranged on a common side of the housing (13) and / or the circuit board (14).

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