Busbar for measuring a direct and/or alternating current
A busbar for measuring a direct and/or alternating current has connection regions and at least one resistance region arranged between the connection regions, and two measuring contacts arranged in the resistance region. The busbar has a geometry in which the measuring contacts are currentless during operation of the busbar. The busbar is formed in one piece. An apparatus for determining current and having such a busbar and a power converter having such an apparatus are also disclosed.
1 . A busbar comprising connection regions and at least one resistance region arranged between the connection regions for measuring a direct and/or alternating current with current intensities greater than 100 amperes, and comprising two measuring contacts which are arranged in the resistance region, wherein the measuring contacts are arranged on respective measuring point plateaus which are connected to a current-carrying region of the resistance region via respective connecting cross pieces that run transversely to a longitudinal center axis of the busbar, wherein recesses are arranged on both sides of the measuring point plateaus along the longitudinal center axis such that the measuring point plateaus are currentless during operation of the busbar, wherein the busbar is formed in one piece and made of a single material.
2 . The busbar according to claim 1 , wherein the resistance region is formed by a taper of a cross-section thereof relative to a cross-section of the connection regions of the busbar, wherein the taper is formed by a reduction in a width of the resistance region to a value between 10 and 60 percent of the width of the connection regions of the busbar.
3 . The busbar according to claim 1 , wherein the longitudinal center axis (LA) runs through the resistance region in a longitudinal direction of the busbar from one of the connection regions to an opposite connection region, wherein the measuring contacts are arranged in a region of the longitudinal center axis (LA), and wherein the busbar is symmetrical in relation to the longitudinal center axis (LA) at least between relevant connection regions.
4 . The busbar according to claim 1 , wherein the busbar, at least between the connection regions, is symmetrical in relation to a respective transverse center axis (QA) which runs centrally between respective connection regions in a transverse direction of the busbar, and wherein the measuring contacts are arranged symmetrically in relation to the transverse center axis (QA).
5 . The busbar according to claim 1 , wherein at least one temperature sensor is arranged between the measuring contacts, in a region of a longitudinal center axis (LA) and/or a transverse center axis (QA).
6 . The busbar according to claim 1 , wherein the longitudinal center axis (LA) forms an axis of symmetry of one or more of the recesses and/or at least two of the recesses are arranged symmetrically in relation to the transverse center axis (QA).
7 . The busbar according to claim 1 , wherein the recesses are formed symmetrically in relation to the respective measuring contact along the longitudinal center axis (LA) and/or the transverse center axis (QA).
8 . The busbar according to claim 1 , wherein the connecting crosspieces have a width between two and five millimeters, and wherein the measurement point plateaus have a longitudinal extension between five and twelve millimeters.
9 . The busbar according to claim 1 , wherein the recesses arranged on both sides of the measuring point plateaus are intersected centrally by the longitudinal center axis (LA) and have a width of between two and ten millimeters in a direction of the longitudinal center axis (LA).
10 . The busbar according to claim 1 , wherein a material thickness of the resistance region and/or of the connection regions is between two and six millimeters.
11 . The busbar according to claim 1 , wherein the busbar is made of copper or aluminum and/or wherein at least the recesses have been punched out.
12 . The busbar according to claim 1 , wherein the measuring contacts are configured as press-fit pins which are pressed into press-fit holes in the busbar.
13 . An apparatus for determining current having a multi-channel busbar according to claim 1 and a printed circuit board arranged in a plane-parallel manner with respect to the busbar for measured value acquisition, wherein the measured value acquisition comprises an acquisition of a voltage difference between the two measuring contacts arranged in the resistance region and a temperature acquisition via at least one temperature sensor of the respective resistance region.
14 . A power converter comprising current-carrying lines for conducting the direct and/or alternating currents processed by the power converter, wherein the power converter comprises a multi-channel apparatus for determining current having a multi-channel busbar comprising on a first side, at least two individual connection regions for connecting a plurality of the current-carrying lines and, on a second side, a common busbar as a common connection region, wherein resistance regions are arranged between the respective individual connection region and the common busbar for measuring direct and/or alternating currents with current intensities greater than 100 amperes, further comprising two measuring contacts arranged in each respective resistance region, wherein the multi-channel busbar has a geometry in which regions of the measuring contacts are currentless during operation of the power converter, the multi-channel apparatus further comprising a printed circuit board arranged in a plane-parallel manner with respect to the busbar for measured value acquisition, wherein the measured value acquisition comprises an acquisition of a voltage difference between the two measuring contacts of a respective resistance region, wherein the multi-channel apparatus bridges respective interruptions of the current-carrying lines, wherein the power converter is designed to determine, using the voltage differences detected by means of the measuring contacts along the respective resistance regions of the busbar, currents flowing through the current-carrying lines during operation of the power converter, wherein the power converter is configured to have a nominal power that is greater than 10 kW.
15 . The power converter according to claim 14 , wherein a printed circuit board for measurement values acquisition is arranged in a plane-parallel manner with respect to the busbar, wherein the printed circuit board covers a plurality of resistance regions and is connected to the measuring contacts of a plurality of resistance regions.
16 . The power converter according to claim 15 , wherein the printed circuit board comprises an evaluation circuit configured to preprocess measured voltages and temperatures of individual ones or the resistance regions, as well as a galvanic isolation, wherein the evaluation circuit is connected to a control circuit of the power converter via the galvanic isolation.
17 . The power converter according to claim 14 , wherein the printed circuit board has slots arranged between the resistance regions and extending parallel to the longitudinal center axis (LA) from an edge of the printed circuit board over at least half of a length of the printed circuit board.