DE102023201916B3 - AC busbar - Google Patents

Abstract

What is proposed is an AC busbar having three phases arranged in series, each of which has a head area for connection to an inverter and a rail area for connection to an electric machine, and each of the rail areas has notches such that a web is formed , through which the rail area is narrowed, and wherein the rail area of the two outer of the three phases is bent such that the area with the notches is orthogonal to the rail area of the middle phase, and an end area thereof is again parallel to it, and where the notches of the middle phase are located in the area of a transition between the orthogonal and parallel course of the outer rail areas to the middle rail area, the notches of the outer phases being opposite one another and the notches of the middle phase being arranged offset from one another.

Description

The present invention relates to the field of electromobility, in particular AC busbars for an electric drive.

The transmission performance of electrical lines running parallel to one another can be impaired by so-called crosstalk, also known as crosstalk. Therefore, it is always a goal to avoid crosstalk as much as possible.

Methods are already known through which a reduction in crosstalk can be achieved using software. The disadvantage here is that two coefficients always have to be determined at the end of the line (EOL=end of line), i.e. at the end of the assembly. Since this is complex, the invention is based on the object of providing an improved AC busbar in which crosstalk is reduced.

The DE 10 2022 101 970 A1 relates to a magnetic core-free current sensor module for measuring a current flow through a busbar.

This task is solved by the features of the independent claims. Advantageous refinements are the subject of the dependent claims.

What is proposed is an AC busbar (AC = alternating current; busbar = bus bar), having three phases arranged in series, each of which has a head area for connection to an inverter and a rail area for connection to an electric machine, and each of the rail areas Notches such that a web is formed through which the rail area is narrowed, and wherein the rail area of the two outer of the three phases is bent such that the area with the notches is orthogonal to the rail area of the middle phase, and an end area thereof is again parallel to it, and wherein the notches of the middle phase are located in the area of a transition between the orthogonal and parallel course of the outer rail areas to the middle rail area, the notches of the outer phases being opposite one another and the notches of the middle phase being arranged offset from one another.

In one embodiment, a Hall sensor is arranged on each web. The Hall sensor of the middle phase is rotated by 45 degrees to the Hall sensors of the outer phases.

By offsetting the notches in the middle phase, the middle web and the Hall sensor arranged on it are at an angle to the webs of the two outer phases, so that now only the magnetic field of one of the other two phases couples into the middle phase, while the coupling of the other phase is negligible.

Furthermore, an inverter with the AC busbar and an electric drive for a motor vehicle with at least one electric machine, a transmission device and the inverter are provided, as well as a motor vehicle with the electric drive.

Further features and advantages of the invention result from the following description of exemplary embodiments of the invention, based on the figures of the drawing, which show details of the invention, and from the claims. The individual features can be implemented individually or in groups in any combination in a variant of the invention.

• 1 zeigt einen prinzipiellen Aufbau einer dreiphasigen AC-Busbar gemäß dem Stand der Technik.
• 2 zeigt einen prinzipiellen Aufbau einer dreiphasigen AC-Busbar gemäß einer Ausführung der vorliegenden Erfindung.
• 3 zeigt die mittlere Phase der in 2 gezeigten Busbar im Detail.

Preferred embodiments of the invention are explained in more detail below with reference to the accompanying drawing.

• 1 shows a basic structure of a three-phase AC busbar according to the state of the art.
• 2 shows a basic structure of a three-phase AC busbar according to an embodiment of the present invention.
• 3 shows the middle phase of the in 2 shown bus bar in detail.

In the following descriptions of the figures, the same elements or functions are given the same reference numbers.

The AC busbar 100 described below is preferably used in the field of electromobility. Here it is used in the area of electronic modules, especially in power electronics, to connect an electric machine, i.e. an electric drive, and an inverter.

The AC-Busbar 100 is used in systems with at least three phases 1, 2, 3. The three phases 1, 2, 3 are arranged next to each other and each have a rail area 11, 21, 31 for connection to the electric machine and a head area 20 for connection to the inverter. The head areas 20 are significantly wider than the rail areas 11, 21, 31, so that the rail areas 11, 31 of the two outer phases, here phases 1 and 3, are bent twice so that their end areas, with which they are connected to the electric machine be connected, as close as possible to the end region of the rail region 21 of the middle phase, here Phase 2, introduced and parallel to it. Due to the bending, a portion of the rail regions 11, 31 of the outer phases 1, 3 is essentially orthogonal to the rail region 21 of the middle phase.

Currently, opposite notches 111, 211, 212, 333 are provided in all rail areas 11, 21 and 31, which narrow the respective rail area 11, 21, 31, so that only one web 112, 213, 334 is present there, as in 1 to see. The webs 112, 334 of the outer phases 1 and 3 point in the direction of the middle phase 2. The web 213 of the middle phase 2 is currently arranged orthogonally to it. Hall sensors 40 are advantageously arranged on all webs 112, 213, 334 in order to measure the respective magnetic field and thus determine the current. So they serve as current sensors.

bezeichnet. Die in den äußeren Phasen 1 und 3 gebildeten Magnetfelder $\overrightarrow{H_1},\overrightarrow{H_3}$

koppeln zumindest teilweise in die mittlere Phase 2 ein, da die Magnetfelder $\overrightarrow{H_1},\overrightarrow{H_2},\overrightarrow{H_3}$

nicht im rechten Winkel zueinander stehen (und somit dämpfend wirken würden). Dies ist mit den verschiedenen Magnetfeldwinkeln (Pfeile für Phase 1) in 1 angedeutet. Somit entsteht unerwünschter Crosstalk (Übersprechen von einer Phase auf die andere), welcher bei der finalen Prüfung am Ende der Montage (end of line-Prüfung) durch Ermittlung von aktuell zwei Kompensationskoeffizienten reduziert werden muss. Dies ist mathematisch aufwändig. Außerdem können äußere Einflüsse wie Temperatur, mechanische Veränderungen über die Lebenszeit etc. Einfluss auf beide Kompensationskoeffizienten haben, so dass diese Einflüsse ebenfalls berücksichtigt werden müssen.The notches 211, 212 in the rail area of the middle phase 2 are provided approximately at the level of the second bend in the outer phases 1, 3. A magnetic field is formed on each web 112, 213, 334 formed by the narrowed areas $\stackrel{}{H_{}}$$\overrightarrow{{}_1},\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="DE102023201916B3\_0008.png,DE102023201916B3\_0009.png"\; state="\{\{state\}\}">H</figure-callout>}}_2},\overrightarrow{{\mathrm{<figure-callout\; id="3"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_3}$

designated. The magnetic fields formed in the outer phases 1 and 3 $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_1},\overrightarrow{H_3}$

couple at least partially into the middle phase 2 because the magnetic fields $\stackrel{}{H_{}}$$\overrightarrow{{}_1},\overrightarrow{{\mathrm{<figure-callout\; id="2"\; label="H"\; filenames="DE102023201916B3\_0008.png,DE102023201916B3\_0009.png"\; state="\{\{state\}\}">H</figure-callout>}}_2},\overrightarrow{{\mathrm{<figure-callout\; id="3"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_3}$

are not at right angles to each other (and would therefore have a dampening effect). This is with the different magnetic field angles (arrows for phase 1). 1 indicated. This creates unwanted crosstalk (crosstalk from one phase to the other), which must be reduced during the final test at the end of assembly (end of line test) by determining two compensation coefficients. This is mathematically complex. In addition, external influences such as temperature, mechanical changes over the lifetime, etc. can have an influence on both compensation coefficients, so these influences must also be taken into account.

In order to solve this problem and better reduce crosstalk, according to the invention the notches 211, 212 in the rail area 21 of the middle phase 2 are not as in 1 shown prior art arranged opposite each other, but offset from each other, as in 2 and 3 shown. This means that the web 213 and the Hall sensor 40 arranged on it are also rotated by 45 degrees. The notches 211, 212 are advantageously offset in such a way that the magnetic field of one of the two outer phases 1 or 3 scatters, if possible, at an angle of 90 degrees to the middle phase 2, since this does not result in any coupling (but rather attenuation), as in 2 indicated. The crosstalk is therefore initiated by one of the two outer phases (in 2 This is phase 3) is reduced to the Hall sensor 40 of the middle phase 2 so much that it is negligible. The crosstalk to the Hall sensor 40 of the other phase (in 2 This is phase 1) is increased (at 0 (zero) degrees there is about 2% coupling), but since now only a single compensation coefficient has to be determined in the final test (end of line test), the compensation equation is simplified (one term disappears or becomes zero).

(von Phase 1 oder 3) nicht in die mittlere Phase 2 einkoppeln soll, zueinander versetzt. In 2 ist zu sehen, dass die Einkerbung 212, welche zu der dritten Phase 3 weist, in Richtung unteren Endbereich, also weiter weg vom Kopfbereich 20 versetzt ist bzw. die Einkerbung 211, welche zu der ersten Phase 1 weist, näher zum Kopfbereich 20 versetzt ist und der Steg 213 dadurch nicht mehr orthogonal zu den Stegen 112, 334 ist. Somit kann in dieser Ausführung das Magnetfeld $\overrightarrow{H_3}$

der dritten Phase 3 nicht mehr in die mittlere Phase 2 einkoppeln. Der Hallsensor 40 ist um ca. 45 Grad gedreht im Vergleich zu der Anordnung bei nicht versetzt angeordneten Einkerbungen 211, 212. Selbstverständlich können die Einkerbungen 211, 212 auch genau andersherum versetzt werden, d.h. die zu der ersten Phase 1 weisende Einkerbung 211 kann weiter vom Kopfbereich 20 entfernt sein bzw. die zu der dritten Phase 3 weisende Einkerbung 211 kann näher am Kopfbereich 20 sein. Wie genau die Einkerbungen 211, 212 versetzt werden, hängt von der Anordnung der Phasen 1-3 und der Länge der Schienenbereiche 21 ab.The notches 211, 212 are depending on which of the magnetic fields $\stackrel{}{H_{}}$$\overrightarrow{{}_1},\overrightarrow{{\mathrm{<figure-callout\; id="3"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_3}$

(from phase 1 or 3) should not couple into the middle phase 2, offset from each other. In 2 It can be seen that the notch 212, which points to the third phase 3, is offset towards the lower end region, i.e. further away from the head region 20, or the notch 211, which points to the first phase 1, is offset closer to the head region 20 and the web 213 is therefore no longer orthogonal to the webs 112, 334. Thus, in this version, the magnetic field $\stackrel{}{H_{}}$$\overrightarrow{{}_3}$

the third phase 3 no longer couples into the middle phase 2. The Hall sensor 40 is rotated by approximately 45 degrees compared to the arrangement with notches 211, 212 that are not offset. Of course, the notches 211, 212 can also be offset exactly the other way around, that is, the notch 211 pointing to the first phase 1 can be further away Head area 20 can be removed or the notch 211 pointing to the third phase 3 can be closer to the head area 20. How exactly the notches 211, 212 are offset depends on the arrangement of phases 1-3 and the length of the rail areas 21.

der beiden äußeren Phasen 1 und 3 in die mittlere Phase 2 ein (in der gezeigten Ausführung ist dies Phase 1), so dass die Berechnung der Kompensationskoeffizienten vereinfacht wird. Bisher hätte noch der Kompensationskoeffizient zwischen Phasen 2 und 3 sowie der Strom durch Phase 3 berücksichtigt werden müssen. Diese Komponenten entfallen (werden zu Null) aber durch die versetzte Anordnung der Einkerbungen 211, 212 in der mittleren Phase 2.As already mentioned, only one of the magnetic fields couples by offsetting the notches 211, 212 $\overrightarrow{{\mathrm{<figure-callout\; id="1"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_1},\overrightarrow{{\mathrm{<figure-callout\; id="3"\; label="H"\; filenames="DE102023201916B3\_0008.png"\; state="\{\{state\}\}">H</figure-callout>}}_3}$

of the two outer phases 1 and 3 into the middle phase 2 (in the embodiment shown this is phase 1), so that the calculation of the compensation coefficients is simplified. Until now, the compensation coefficient between phases 2 and 3 as well as the current through phase 3 would have had to be taken into account. These components are eliminated (become zero) due to the offset arrangement of the notches 211, 212 in the middle phase 2.

wobei
i_komp_2: Stromwert von Phase 2, bei dem der Einfluss von Phase 1 herausgerechnet wurde, also der Strom, der in Phase 2 tatsächlich (ohne Einfluss von Phase 1) fließt,
i_1, i _2: Strom durch Phasen 1 und 2,
k_12: Kompensationskoeffizient (Koppelfaktor) zwischen Phasen 1 und 2, wobei dessen Vorzeichen vom Winkelversatz der drei Phasen abhängt.This makes the compensation equation for the compensation current i_komp_2 in the second phase 2 simpler. The compensation current i_komp_2 is calculated as follows in the case shown in the figure: $$i\_kOmp\_2=i\_2-k_{12}\ast i\_\mathrm{1,}\text{where}$$

where
i_komp_2: Current value of phase 2, for which the influence of phase 1 was eliminated, i.e Current that actually flows in phase 2 (without influence from phase 1),
i_1, i _2: current through phases 1 and 2,
k_12: Compensation coefficient (coupling factor) between phases 1 and 2, whereby its sign depends on the angular offset of the three phases.

By rearranging the equation (Eq. 1), the compensation coefficient ((coupling factor)) k_12 can be calculated.

In the event that the notches 211, 212 are offset the other way around in the middle phase, the current i_3 of phase 3 must of course be taken into account, since the current i_1 of phase 1 would then have no influence and would therefore become zero.

Another advantage of the fact that only a single compensation coefficient now has to be taken into account is that the computing time in the microcontroller is reduced. In addition, the influence of temperature, mechanical changes over life, is reduced because there is only one coefficient that can change.

An electronic module within the scope of this invention is used to operate an electric drive of a vehicle, in particular an electric vehicle and/or a hybrid vehicle, and/or electrified axles. The electronic module includes a DC/AC inverter. It may also include an AC/DC rectifier, a DC/DC converter, a transformer, and/or another electrical converter or part of one include or be a part of such a converter. In particular, the electronic module is used to power an electric machine, for example an electric motor and/or a generator. A DC/AC inverter is preferably used to generate a multi-phase alternating current from a direct current generated by means of a DC voltage from an energy source, such as a battery.

Inverters for electric drives of vehicles, especially cars and commercial vehicles, as well as buses, are designed for the high-voltage range and are designed in particular in a reverse voltage class of approximately 650 volts.

Reference symbol list

100

AC busbar

1, 2, 3

first, second, third phase

20

Head area

21

Rail area

11, 31

Rail area phase 1, 3

111,333

Notches in 11.31

211, 212

Notches in 21

213

web

112, 334

Bridge at 21.31

40

Hall sensor

Claims (5)

AC busbar (100), having three phases (1, 2, 3) arranged in series, each of which has a head area (20) for connection to an inverter and a rail area (11, 21, 31) for connection to an electric Machine, and wherein each of the rail areas (11, 21, 31) has notches (111; 211, 212; 333) such that a web (112, 213, 334) is formed through which the rail area (11, 21, 31) is narrowed, and wherein the rail area (11, 31) of the two outer of the three phases (1, 3) is bent such that the area with the notches (111, 333) is orthogonal to the rail area (21) of the middle phase (2), and an end region thereof is again parallel to it, and wherein the notches (211, 212) of the middle phase (2) are in the area of a transition between orthogonal and parallel course of the outer rail regions (11, 31) to the middle rail region (21), the notches (111, 333) of the outer phases (1, 3) being opposite one another and the notches (211, 212) of the middle phase (2) being arranged offset from one another. AC busbar (100). Claim 1 , wherein a Hall sensor (40) is arranged on each web (112, 213, 334), and wherein the Hall sensor (40) of the middle phase (2) is arranged rotated by 45 degrees to the Hall sensors of the outer phases (1, 3). . Inverter with an AC busbar (100) according to one of the preceding claims. Electric axle drive for a motor vehicle with at least one electric machine, a transmission device and an inverter, characterized in that the inverter Claim 3 is trained. Motor vehicle, comprising an electric axle drive Claim 4 .

Images