Circuit arrangement for reducing common-mode interference in a converter

Abstract

The invention relates to a circuit arrangement (100) for reducing common-mode interference of a converter (60), wherein the converter (60) forms a common-mode interference source during operation. The circuit arrangement (100) comprises at least one short-circuited additional line (50) which can be coupled to an input (10, 15) and an output (20, 25, 30) of the converter (60), wherein the additional line (50) conducts interference currents generated by the common-mode interference source and returns the interference currents to the common-mode interference source.

Description

Technical Field

[0001] The present invention relates to a circuit arrangement for reducing common-mode interference of a converter. The present invention also relates to a power electronics system having a corresponding circuit arrangement and an electric vehicle having a power electronics system. Background Art

[0002] During the operation of transformers, common-mode interference occurs, which causes electromagnetic radiation. This electromagnetic radiation must be minimized during the operation of electrical systems so that these systems do not affect other systems in the environment. Various solutions are known for electromagnetically shielding individual current-carrying lines. For example, DE 10 2014 224 267 A1 discloses a cable sheath for encapsulating electrical lines. Alternatively, filter components composed of capacitors and inductors are known to minimize electromagnetic radiation. These known solutions are implemented using discrete components, which are added to the actual circuit, require structural space, and incur additional costs. Furthermore, efforts are underway to find simpler solutions. Summary of the Invention

[0003] The present invention relates to a circuit arrangement for reducing common-mode interference in a converter, wherein the converter constitutes a common-mode interference source during operation. The circuit arrangement includes at least one short-circuited additional line that can be coupled to the input and output of the converter. The additional line conducts interference currents generated by the common-mode interference source and directs them back to the common-mode interference source.

[0004] Therefore, a circuit arrangement is provided for reducing common-mode interference in a converter, wherein the converter constitutes a common-mode interference source during operation. There are various types of converters. A converter for converting alternating current into direct current is called a rectifier. An inverter converts direct current into alternating current. A converter is used to convert one alternating current into another; for example, a frequency converter is used to change the frequency of the alternating current. A DC transformer converts a first DC voltage into a second DC voltage, which can be higher, lower, or inverse. The conversion is usually carried out using semiconductor-based electronic components, such as diodes, transistors, or thyristors, in particular MOSFETs, IGBTs, and IGCTs. Vacuum tubes, mercury vapor rectifiers, and thyristors have also been used in the past. In this case, capacitors or inductors are usually used as intermediate energy storage devices in the device.

[0005] The converter is preferably a transformer, a DC transformer, an inverter, or a current converter. The converter is preferably a combination of at least one or more DC transformers, inverters, and / or converters connected in series or in parallel. The converter preferably has a different number of input and output lines. Furthermore, the converter preferably includes passive components, preferably diodes, or active components, preferably semiconductor switching elements. The circuit arrangement includes at least one short-circuited additional line that can be coupled to the input and output of the converter. The short-circuited additional line is preferably a ring line in which current, in particular interference current generated by common-mode interference sources, can be conducted in a loop. "Coupleable" within the scope of these embodiments means that the additional line can be attached to the input and output of the converter, preferably inductively, capacitively, or conductively, for example, via a common choke. The input of the converter preferably includes first and second input lines. The output of the converter preferably includes multiple output lines on the output side. Preferably, the converter is an inverter. The input of the inverter preferably includes first and second DC voltage lines as input lines. The output of the inverter preferably includes multiple phases on the output side, preferably three phases or multiple phase lines for supplying an electric motor, as output lines on the AC voltage side. This coupling allows short-circuited additional lines to conduct interference currents generated by common-mode interference sources and redirect them back to the common-mode interference sources. Common-mode interference sources are generated, in particular, during operation of the converter within the converter, particularly due to switching operations of semiconductor switches, which preferably use one or more half-bridges to convert an input voltage into an output voltage by opening and closing the switches of at least one half-bridge in a clocked manner. Common-mode interference sources are generated, in particular, within the converter during operation, preferably by using a B6 bridge to convert an input DC voltage into a multi-phase output AC voltage by opening and closing the switches of the B6 bridge in a clocked manner. Advantageously, a circuit arrangement is provided that absorbs the generated interference currents, thereby reducing electromagnetic radiation from the converter.

[0006] In another embodiment of the present invention, the circuit arrangement includes a first common-mode choke through which the additional line is routed. Preferably, the additional line is wound around the first common-mode choke at least once, preferably ten times. Preferably, the first common-mode choke is arranged on the input voltage side of the converter.

[0007] The circuit arrangement includes a first common-mode choke through which an additional line is routed. This results in inductive coupling to the line also routed through the common-mode choke. To increase the inductive effect and thus enhance the inductive coupling, the additional line is wound around the first common-mode choke at least once, preferably ten times. Preferably, the first common-mode choke is arranged on the input voltage side of the converter. This allows the additional line to be coupled to the converter input. Advantageously, a circuit arrangement with improved coupling is provided, which absorbs generated interference currents and thereby reduces electromagnetic radiation from the converter.

[0008] In another embodiment of the present invention, the circuit arrangement includes a second common-mode choke through which the additional line is routed. Preferably, the additional line is wound around the second common-mode choke at least once, preferably ten times. Preferably, the second common-mode choke is arranged on the output voltage side of the converter.

[0009] The circuit arrangement includes a second common-mode choke through which the additional line is routed. This results in inductive coupling to the line also routed through the common-mode choke. To increase the inductive effect and thus enhance the inductive coupling, the additional line is wound around the second common-mode choke at least once, preferably ten times. Preferably, the second common-mode choke is arranged on the output voltage side of the converter. This allows the additional line to couple to the converter output. Advantageously, a circuit arrangement with improved coupling is provided, which absorbs generated interference currents and thereby reduces electromagnetic radiation from the converter.

[0010] In a further embodiment of the invention, the additional line of the circuit arrangement can be electrically connected to the reference conductor or by means of a capacitor or a coil.

[0011] The additional lines of the circuit arrangement can be electrically connected to the reference conductor. Within the scope of these embodiments, the reference conductor is understood to be a line to which the ground terminal of the converter is attached. Preferably, the reference conductor is electrically connected to the protective conductor at only one location. The reference conductor forms a common return conductor for the various electrical components to be connected and also conducts current when the electrical components are in operation. The reference conductor is preferably a common ground terminal of the electrical system or, for example, the chassis of a vehicle, or the reference conductor is connected to the common ground terminal or chassis with low impedance. The protective conductor only conducts current in the event of a fault, for example, in the event of a short circuit between the power supply line and the housing of an electrical component, such as a converter, to which the reference conductor is connected. Advantageously, a solution for improving the operational safety of the circuit arrangement is provided.

[0012] In a further embodiment of the present invention, the additional line of the circuit arrangement comprises at least one damping element which minimizes interference currents on the additional line.

[0013] The additional circuit of the circuit arrangement includes at least one damping component. The damping component influences interference currents on the additional circuit. Preferably, electrical energy of the interference current is converted into heat. Advantageously, a circuit arrangement is provided that effectively absorbs generated interference currents, thereby reducing electromagnetic radiation from the converter.

[0014] In another embodiment of the present invention, the damping component includes at least one resistor.

[0015] A resistor is used as a damping element, which converts the electrical energy of the interference current into heat energy. Advantageously, a circuit arrangement is provided which absorbs the generated interference currents more effectively and thus reduces the electromagnetic radiation of the converter.

[0016] In another embodiment of the present invention, the attenuation component includes a separation portion that separates the additional line into a first short-circuited additional line having a first resistor and a second short-circuited additional line having a second resistor. Preferably, the first short-circuited additional line can be capacitively connected to the reference conductor via a first capacitor and / or the second short-circuited additional line can be capacitively connected to the reference conductor via a second capacitor.

[0017] The attenuation component includes a separation portion of the additional circuit. Interference currents are prevented from flowing from the input end to the output end and back in the additional circuit of the converter. Instead, a first short-circuited additional circuit with a first resistor is generated on the input side and a second short-circuited additional circuit with a second resistor is generated on the output side. The resistance attenuates the interference currents in the first and second short-circuited additional circuits. As a result, the common-mode currents at the input and output ends of the converter are attenuated. Preferably, the first short-circuited additional circuit can be capacitively connected to the reference conductor by means of a first capacitor and / or the second short-circuited additional circuit can be capacitively connected to the reference conductor by means of a second capacitor. The connection by means of the capacitors causes additional high-frequency attenuation. Advantageously, an alternative circuit arrangement is provided that absorbs the generated interference currents and thereby reduces the electromagnetic radiation of the converter.

[0018] In another embodiment of the present invention, the circuit arrangement includes an input-side capacitor and an output-side capacitor. The additional circuit is designed as a shorted series circuit comprising a first common-mode choke, a first resistor, a second common-mode choke, and a second resistor. The input-side capacitor is arranged between the first resistor and the first common-mode choke for connection to the input circuit of the converter on the input side, and the output-side capacitor is arranged between the first resistor and the second common-mode choke for connection to the output circuit of the converter on the output side. The first resistor is preferably significantly larger than the second resistor, preferably with a value difference of 10 times.

[0019] The circuit arrangement includes an input-side capacitor and an output-side capacitor. Within the scope of these embodiments, the input-side capacitor is a capacitor that can be attached between the input line and the additional line of the converter. Within the scope of these embodiments, the output-side capacitor is a capacitor that can be attached between the output line and the additional line of the converter. The additional line is designed as a short-circuited series circuit of a first common-mode choke, a first resistor, a second common-mode choke, and a second resistor. The input-side capacitor is arranged between the first resistor and the first common-mode choke for attachment to the input line of the converter on the input side. The output-side capacitor is arranged between the first resistor and the second common-mode choke for attachment to the output line of the converter on the output side. The capacitor provides a low-impedance path for common-mode current. In combination with the common-mode choke, a filter with an LC or CL topology is preferably obtained on the input and output sides. Preferably, the first resistor is significantly larger than the second resistor, preferably with the values ​​of the resistors differing by a factor of 10. This prevents overheating of the input-side capacitors and the output-side capacitors. Advantageously, an alternative circuit arrangement is provided which absorbs the generated interference currents and thus reduces the electromagnetic radiation of the converter.

[0020] In another embodiment of the present invention, the circuit arrangement includes an output-side capacitor. The additional circuit is designed as a shorted series circuit of a first common-mode choke and a first resistor. The output-side capacitor is arranged between the first resistor and the first common-mode choke for connection to the output circuit of the converter on the output side. Preferably, the additional circuit is capacitively connectable to the reference conductor via the first capacitor. This capacitive additional connection provides a greater bandwidth than a purely inductive connection.

[0021] Advantageously, an alternative circuit arrangement is provided which absorbs the generated interference currents and thus reduces the electromagnetic radiation of the converter.

[0022] Furthermore, the invention relates to a power electronics system having a converter and an attached circuit arrangement as described.

[0023] A power electronics system is provided, comprising a converter and an attached circuit arrangement. Advantageously, a power electronics system is provided, in which a reduction in electromagnetic radiation is achieved.

[0024] In another embodiment of the present invention, the power electronics system includes an attached DC voltage source and / or an attached multi-phase electric machine.

[0025] A power electronics system is provided, comprising an attached DC voltage source, preferably a high-voltage battery, a fuel cell and / or a photovoltaic system, and / or an attached multi-phase electric machine, preferably a synchronous or asynchronous electric machine. Advantageously, a power electronics system is provided in which a reduction in electromagnetic radiation is achieved.

[0026] Furthermore, the invention relates to an electric vehicle having a power electronics system.

[0027] An electric vehicle, in particular a motor vehicle, a passenger car or a truck or a water vehicle or an air vehicle, is provided with a power electronics system. Advantageously, a vehicle is provided in which a reduction in electromagnetic radiation is achieved.

[0028] Therefore, preferably, the circuit arrangement or power electronics system is provided for use in all shielded and unshielded electric and hybrid drive systems in the automotive sector, in 48V motor vehicle drive systems, in industrial drives of all voltage levels, in the field of electrical energy supply, in particular also in converter systems in photovoltaic inverters or in DC converters.

[0029] Common-mode interference sources and electrical components attached to the converter, such as energy sources or energy absorbers, can preferably also be electromagnetically decoupled from high-impedance components. For improved filtering, additional components can also preferably provide an alternative low-impedance path for common-mode currents.

[0030] It should be understood that the features, characteristics, and advantages of the circuit arrangement are correspondingly applicable or applicable to the power electronics system or the electric vehicle, and vice versa.

[0031] Further features and advantages of embodiments of the present invention will be apparent from the following description with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The invention will be explained in more detail below with reference to the accompanying drawings, which show:

[0033] Figure 1 A first exemplary embodiment is shown in a schematic diagram of a circuit arrangement and a power electronics system;

[0034] Figure 2 A second embodiment is shown in a schematic diagram of a circuit arrangement and a power electronics system;

[0035] Figure 3 A third embodiment is shown in a schematic diagram of a circuit arrangement and a power electronics system;

[0036] Figure 4 A fourth exemplary embodiment is shown in a schematic diagram of a circuit arrangement and a power electronics system;

[0037] Figure 5A fifth embodiment is shown in a schematic diagram of a circuit arrangement and a power electronics system;

[0038] Figure 6 The sixth exemplary embodiment is shown in a schematic diagram of an electric vehicle having a power electronics system with a circuit arrangement. DETAILED DESCRIPTION

[0039] Figure 1 A first embodiment is shown in a schematic diagram of a circuit arrangement 100 and a power electronics system 200. Circuit arrangement 100 includes a short-circuited additional line 50 that can be coupled to the input of a converter 60, preferably including input lines 10 and 15 on the input side, and preferably including output lines 20, 25, and 30 on the output side. Converter 60, preferably the circuit, and / or the housing of converter 60, serving as a ground connection, is electrically connected to a reference conductor 65. To couple additional line 50 to the input of converter 60, circuit arrangement 100 preferably includes at least one first common-mode choke 75, through which the input lines 10 and 15 and additional line 50 are routed or wound. Furthermore, to couple additional line 50 to the output of converter 60, circuit arrangement 100 preferably includes a second common-mode choke 70, through which the output lines 20, 25, and 30 and additional line 50 are routed or wound. The converter 60 generates common-mode interference during operation and, in particular, forms a common-mode voltage source. This common-mode voltage source results in the following common-mode current, which is preferably coupled out via the first and second common-mode chokes 70, 75 and transmitted back from the common-mode interference source to the common-mode interference source via the additional line 50. Preferably, the additional line 50 includes an attenuation component 80, in particular a resistor, for attenuating the common-mode current in the additional line 50. The electrical energy of the common-mode current can be converted into heat energy via the attenuation element 80, such as a resistor. Preferably, the additional line 50 is also electrically connected to the reference conductor 65 to achieve wider bandwidth filtering at higher frequencies. The reference conductor 65 is connected or grounded at one location to the protective conductor 67 or the ground terminal, or to the vehicle ground terminal. The converter 60 and the coupled circuit device 100 form a power electronics system 200.

[0040] and Figure 1 different, Figure 2A second exemplary embodiment is shown in a schematic diagram of a circuit arrangement 100 and a power electronics system 200. Circuit arrangement 100 includes a special embodiment of a shorted additional line 50 with a maximum effective damping element, namely, a split portion of the additional line 50. This results in a first shorted additional line 52 having a first resistor 53 and a second shorted additional line 54 having a second resistor 55. The first additional line 52 can be coupled to a converter 60 on the input side. The second additional line 54 can be coupled to a converter 60 on the output side. To couple the additional line 52, circuit arrangement 100 preferably includes at least one first common-mode choke 75, through which the input lines 10, 15 and the additional line 52 are routed or wound. Furthermore, to couple the additional line 54, circuit arrangement 100 preferably includes a second common-mode choke 70, through which the output lines 20, 25, 30 and the additional line 54 are routed or wound. Preferably, the first short-circuited additional line 52 can be capacitively connected to the reference conductor 65 by means of a first capacitor 56 and / or the second short-circuited additional line 54 by means of a second capacitor 58. This allows the input side and the output side to be optimized individually. The converter 60 generates common-mode interference during operation and, in particular, forms a common-mode voltage source. This common-mode voltage source causes the following common-mode current, which is coupled out via the first and second common-mode chokes 70, 75 and transmitted back from the common-mode interference source to the common-mode interference source via the additional lines 52, 54, preferably via the first and second capacitors 56, 58 and the reference conductor 65. The additional lines 52 and 54 include resistors 53 and 55 as attenuation components 80 for attenuating the common-mode current in the additional lines 52, 54. The converter 60 and the coupled circuit device 100 form a power electronic system 200.

[0041] and Figure 1 different, Figure 3A third embodiment is shown in a schematic diagram of a circuit arrangement 100 and a power electronics system 200. Circuit arrangement 100 includes a shorted additional line 50 that can be coupled to the input of a converter 60, preferably comprising input lines 10, 15 on the input side, and preferably comprising output lines 20, 25, 30 on the output side. Circuit arrangement 100 includes input-side capacitors 110, 120 and output-side capacitors 130, 140, 150. The additional line is designed as a shorted series circuit of a first common-mode choke 75, a first resistor 160, a second common-mode choke 70, and a second resistor 170. Input-side capacitors 110, 120 are arranged between first resistor 160 and first common-mode choke 75 for input-side connection to the input lines of converter 60. Output-side capacitors 130, 140, and 150 are arranged between the first resistor 160 and the second common-mode choke 70 for connection to the output line of the converter 60. The first resistor 160 is preferably significantly larger than the second resistor 170. The ratio of the first resistor 160 to the second resistor 170 is preferably approximately 10. During operation, the converter 60 generates common-mode interference and, in particular, forms a common-mode voltage source. This common-mode voltage source results in common-mode currents that are coupled out via the first and second common-mode chokes 70, 75, the input-side capacitors 110, 120, and the output-side capacitors 130, 140, and 150 and transmitted back from the common-mode interference source to the source via the additional line 50. The additional line 50 is preferably not electrically connected to the reference conductor 65. The reference conductor 65 is connected to a protective conductor 67 or grounded at one point. The converter 60 and the coupled circuit arrangement 100 form a power electronics system 200.

[0042] and Figure 1 different, Figure 4A fourth exemplary embodiment is shown in a schematic diagram of a circuit arrangement 100 and a power electronics system 200. Circuit arrangement 100 includes a short-circuited additional line 50 that can be coupled to an input of a converter 60, preferably comprising input lines 10, 15 on the input side, and preferably comprising output lines 20, 25, 30 on the output side. Converter 60, preferably the circuit, and / or the housing serving as a ground connection for converter 60, is electrically connected to a reference conductor 65. To couple additional line 50, circuit arrangement 100 preferably includes at least one first common-mode choke 75, through which input lines 10, 15 and additional line 50 are routed or wound. Furthermore, circuit arrangement 100 includes output-side capacitors 130, 140, 150 for coupling additional line 50. Additional line 50 is designed as a short-circuited series circuit of first common-mode choke 75 and first resistor 160. Output-side capacitors 130, 140, 150 are arranged between the first resistor 160 and the first common-mode choke 75 for attachment to the output line of the converter 60 on the output side. Preferably, the additional line 50 can be capacitively connected to the reference conductor 65 by means of a third capacitor 175. This topology has a particularly high power density. During operation, the converter 60 generates common-mode interference and, in particular, forms a common-mode voltage source. This common-mode voltage source causes the following common-mode current, which is coupled out via the first common-mode choke 75 and the output-side capacitors 130, 140, 150 and transmitted back to the common-mode interference source via the additional line 50. Preferably, the additional line 50 includes a first resistor 160 as an attenuation component for attenuating the common-mode current in the additional line 50. The converter 60 and the coupled circuit device 100 form a power electronics system 200.

[0043] Unlike the drawings shown so far, the Figure 5 A fifth embodiment is shown in a schematic diagram of a circuit arrangement 100 and a power electronics system 200. A converter 60 and the coupled circuit arrangement 100 form the power electronics system 200. The power electronics system 200 also includes an attached DC voltage source 180 and / or an attached multi-phase electric machine 190. The DC voltage source 180 is electrically conductively connected, for example, at its positive and negative poles to one of the input lines 10, 15 of the converter 60. The electric machine 190, shown as an example, is electrically conductively connected at its three phase terminals to one of the output lines 20, 25, 30 of the converter 60. The converter 60 is preferably an inverter for converting the DC voltage of the DC voltage source 180 (preferably a battery) into a multi-phase AC voltage for supplying power to the electric machine, preferably a three-phase electric machine 190. The converter 60, the DC voltage source 180, and / or the electric machine 190, preferably their circuits and / or their housings serving as ground terminals, are electrically connected to a reference conductor 65. The reference conductor 65 is connected to a guard conductor 67 or grounded at one location.

[0044] Figure 6 A sixth exemplary embodiment is shown in a schematic diagram of an electric vehicle 300 having a power electronics system 200 with a circuit arrangement 100. The electric vehicle 300 is preferably a motor vehicle and includes a power electronics system 200 having a circuit arrangement 100 that produces reduced electromagnetic radiation.

Claims

1. A circuit device (100) for reducing common-mode interference of an inverter (60), in, The input (10, 15) of the inverter (60) comprises a first and a second DC voltage line, and the output (20, 25, 30) of the inverter (60) comprises a plurality of phases or phase lines on the AC voltage side, The inverter (60) constitutes a common-mode interference source during operation. The circuit arrangement (100) is characterized in that the circuit arrangement (100) comprises a short-circuited additional line (50) capable of inductive coupling to the input (10, 15) and output (20, 25, 30) of the inverter (60), wherein the additional line (50) is a ring line that guides interference currents generated by common-mode interference sources and returns the interference currents to the common-mode interference sources.

2. The circuit arrangement (100) according to claim 1, wherein The circuit arrangement (100) comprises a first common-mode choke (75), through which the additional line (50) is passed and around which the additional line (50) is wound at least once, wherein the first common-mode choke (75) is arranged on the input side of the inverter (60).

3. The circuit arrangement (100) according to claim 2, wherein The circuit arrangement (100) comprises a second common-mode choke (70), through which the additional line (50) is passed and around which the additional line (50) is wound at least once, wherein the second common-mode choke (70) is arranged on the output side of the inverter (60).

4. The circuit arrangement (100) according to any one of claims 1 to 3, wherein: The additional line (50) of the circuit arrangement (100) can be electrically connected to the reference conductor (65).

5. The circuit arrangement (100) according to claim 3, wherein The additional line (50) of the circuit arrangement (100) comprises at least one damping component (80) which minimizes interference currents on the additional line (50).

6. The circuit arrangement (100) according to claim 5, wherein The attenuation component (80) includes at least one resistor.

7. The circuit arrangement (100) according to claim 5, wherein The attenuation component (80) includes a separation portion for dividing the additional circuit (50) into a first short-circuited additional circuit (52) having a first resistor (53) and a second short-circuited additional circuit (54) having a second resistor (55). The first short-circuited additional line (52) can be capacitively connected to the reference conductor (65) by means of a first capacitor (56) and / or the second short-circuited additional line (54) can be capacitively connected to the reference conductor (65) by means of a second capacitor (58).

8. The circuit arrangement (100) as claimed in claim 6, comprising an input-side capacitor (110, 120) and an output-side capacitor (130, 140, 150), wherein The additional circuit (50) is constructed as a short-circuited series circuit of the first common-mode choke (75), the first resistor (160), the second common-mode choke (70), and the second resistor (170). An input-side capacitor (110, 120) is arranged between the first resistor (160) and the first common-mode choke (75) for attachment to an input line of an inverter (60) on the output side. An output-side capacitor (130, 140, 150) is arranged between the first resistor (160) and the second common-mode choke (70) for attachment to an output line of the inverter (60) on the output side, wherein: The first resistor (160) is much larger than the second resistor (170).

9. The circuit arrangement (100) according to claim 2, comprising output-side capacitors (130, 140, 150), wherein the additional line (50) is designed as a short-circuited series circuit of a first common-mode choke (75) and a first resistor (160), An output-side capacitor (130, 140, 150) is arranged between the first resistor (160) and the first common-mode choke (75) for attachment to an output line of the inverter (60) on the output side. in, The additional line (50) is capacitively connectable to the reference conductor (65) by means of a third capacitor (175).

10. A power electronics system (200) comprising an inverter (60) and an attached circuit arrangement (100) according to any one of claims 1 to 9.

11. The power electronics system (200) according to claim 10, comprising an attached DC voltage source (180) and / or an attached multi-phase electric machine (190).

12. An electric vehicle (300) having a power electronics system (200) according to claim 10 or 11.

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