Rectifier components

Abstract

A rectifier component (20) for rectifying an AC voltage into a DC voltage has a first terminal (21), a second terminal (22), a third terminal (23) and a fourth terminal (24), the rectifier component (20) having an intermediate circuit (50) with a first line (51), a second line (52) and a node (53), the node (53) being connected to the first line (51) via at least one first capacitor (61) and connected to the second line (52) via at least one second capacitor (62), the first terminal (21), the second terminal (22) and the third terminal (23) being connected to a star point (40) via associated circuit components (31, 32, 33), the fourth terminal (24) being likewise connected to the star point (40), and the star point (40) being connected to the node (53) via a controllable switch (45).

Description

Technical Field

[0001] The invention relates to a rectifier assembly. Background Art

[0002] EP 2 226 926 A1 shows an inverter which can generate different output voltages from separate DC voltage sources by means of switches.

[0003] US 2014 / 0375121 A1 shows a converter having a single-phase, two-stage rectifier.

[0004] US 2016 / 0315540 A1 shows a bidirectional AC / DC converter having two capacitors connected in series, by means of which a potential reference can be generated on the DC voltage side.

[0005] No. 5,430,639 A shows an AC / DC converter having a DC link circuit with chokes which are influenced by switches. Summary of the invention

[0006] The object of the present invention is to provide a novel rectifier assembly and a novel vehicle having such a rectifier assembly.

[0007] This object is achieved by a rectifier assembly described in the next paragraph.

[0008] A rectifier assembly for rectifying an AC voltage into a DC voltage has a first terminal, a second terminal, a third terminal and a fourth terminal, the rectifier assembly has an intermediate circuit with a first line, a second line and a node, the node is connected to the first line via at least one first capacitor, and is connected to the second line via at least one second capacitor, the first terminal, the second terminal and the third terminal are each connected to a star point via a corresponding circuit assembly, the fourth terminal is also connected to the star point, and the star point is connected to the node via a controllable switch. The switch can be set to selectively connect or isolate the star point and thereby obtain different characteristics of the rectifier assembly.

[0009] According to a preferred embodiment, the circuit components are each designed to enable a current flow between the circuit component on the one hand and the first line and / or the second line on the other hand. The circuit components can thus feed the intermediate circuit.

[0010] According to a preferred embodiment, the rectifier assembly has a control device which is designed to influence the controllable switch. This allows the controllable switch to be switched automatically.

[0011] According to a preferred embodiment, in the rectifier assembly, the control device is designed to switch the controllable switch to either conducting or non-conducting at the connected power supply network during the entire rectification process. As long as the connected power supply network remains unchanged, there is no need to switch the switch during the rectification process.

[0012] According to a preferred embodiment, in the rectifier assembly, the control device is designed to generate a first value, which first value depends on the power supply network, which is connected to the terminals, and the control device is designed to influence the controllable switch device depending on the first value. This makes it possible to influence the controllable switch device depending on the connected power supply network.

[0013] According to a preferred embodiment, the control device is designed to generate the first value by checking whether the fourth terminal is connected to a neutral conductor. It has proven to be advantageous to switch the controllable switch depending on whether a neutral conductor is present.

[0014] According to a preferred embodiment, the control device is designed to measure the potential at the fourth terminal and to determine whether a neutral conductor is connected to the fourth terminal by means of the time curve of the potential at the fourth terminal. Since significantly smaller potential fluctuations occur at the neutral conductor than at the phase terminals or at the external conductor, it is possible to determine whether a neutral conductor or an external conductor is connected by measuring the potential at the fourth terminal.

[0015] According to a preferred embodiment, the control device is designed to switch the controllable switch to conduction under the condition that the fourth terminal is connected to the neutral conductor. This reduces leakage current and improves safety during the test.

[0016] According to a preferred embodiment, the control device is designed to switch the controllable switch to non-conductive state when the fourth terminal is not connected to the neutral conductor. When not connected to the neutral conductor, the disconnection of the controllable switch in the test reduces the leakage current.

[0017] According to a preferred embodiment, the rectifier assembly has a mains filter which enables leakage currents. The use of such a mains filter improves the EMC properties of the entire circuit and has a positive effect on the optimization achieved by suitable regulation of the controllable switches.

[0018] According to a preferred embodiment, the controllable switch is designed as an electromechanical switch. Such an electromechanical switch has a high insulation effect and does not require fast switching.

[0019] According to a preferred embodiment, the controllable switch is designed as a relay. Relays are very suitable in terms of electrical and mechanical properties.

[0020] This object is also achieved by the vehicle described in the next paragraph.

[0021] A vehicle is designed as an electric vehicle or a hybrid vehicle, and has a corresponding rectifier assembly. A high-power rectifier assembly is required in the vehicle, and the described rectifier assembly has a relatively low leakage current despite its high power.

[0022] According to a preferred embodiment, the vehicle has a plug connector for connecting a charging cable for the vehicle, and there is at least temporarily an electrical coupling between the terminals at the plug connector and the rectifier assembly. According to a preferred embodiment, the vehicle has a traction battery, and there is at least temporarily an electrical coupling between the terminals at the plug connector and the traction battery. In such a design, leakage currents in the rectifier assembly also act outside the vehicle, because there is no electrical isolation. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Further details and advantageous developments of the invention are derived from the exemplary embodiments described below and shown in the drawings, which are not to be understood in any way as limiting the invention, and from the preferred embodiments described above. In the drawings:

[0024] Figure 1 The rectifier assembly is shown,

[0025] Figure 2 Shows the power supply network to Figure 1 The connection of the rectifier components,

[0026] Figure 3 An exemplary use of a rectifier assembly in a vehicle is shown, and

[0027] Figure 4 Show Figure 1 An embodiment of a circuit assembly of a rectifier assembly. DETAILED DESCRIPTION

[0028] Figure 1A rectifier assembly 20 for rectifying an AC voltage into a DC voltage is shown. The rectifier assembly 20 has a first terminal 21, a second terminal 22, a third terminal 23 and a fourth terminal 24. The rectifier assembly 20 has an intermediate circuit 50, which has a first line 51, a second line 52 and a node 53. The node 53 is connected to the first line 51 via a first capacitor 61 and to the second line 52 via at least one second capacitor 62. Preferably, the capacitors 61, 62 are intermediate circuit capacitors for storing energy in the intermediate circuit 50 and for smoothing the DC voltage on the lines 51, 52 and have a capacitance suitable for the respective application. In this embodiment, the intermediate circuit is designed as a DC voltage intermediate circuit. The first terminal 21, the second terminal 22 and the third terminal 23 are each connected to the star point 40 via the assigned circuit components 31, 32, 33, and the fourth terminal 24 is also connected to the star point 40. The star point 40 is connected to the node 53 via a controllable switch 45. Preferably, the rectifier assembly 20 additionally has a fifth terminal 25, via which a protective conductor PE of the power supply network can be connected. A protective conductor symbol 69 is symbolically provided at the fifth terminal 25, which can be used in the rectifier assembly 20 and is also provided there with the reference numeral 69. The power supply network can also be referred to as a power supply.

[0029] The circuit components 31, 32, 33 are each designed to enable a current flow between the circuit components 31, 32, 33 (on the one hand) and the first line 51 or the second line 52 (on the other hand). In order to charge the capacitors 61, 62, a current preferably flows from the circuit components 31, 32, 33 to the first line 51, and a current flows from the second line 52 to the circuit components 31, 32, 33. This results in a higher potential in the first line 51 than in the second line 52. If necessary, it is also possible to generate a higher potential on the second line 52 than on the line 51.

[0030] The rectifier assembly 20 has a control device 41, which is designed to influence the controllable switch 45, that is, in particular to switch this controllable switch to be conductive or non-conductive. The control device 41 is preferably designed to switch the controllable switch 45 to be either conductive or non-conductive at a pre-set power supply network during the entire rectification period. Therefore, after determining whether the controllable switch 45 should be conductive or non-conductive after the rectifier assembly 20 is connected to the power supply network 10, the controllable switch 45 is switched accordingly, and rectification is performed in this set state until the power supply network 10 is separated from the rectifier assembly 20 or the rectification process is terminated.

[0031] The control device 41 is preferably designed to generate a first value VAL1 which is dependent on a power supply network 10 which is connected to the terminals 21 to 24 and to influence the controllable switch 45 dependent on the first value VAL1 .

[0032] The control device 41 is preferably designed to generate the first value VAL1 by checking whether the fourth terminal 24 is connected to the neutral conductor.

[0033] The control device 41 is preferably designed to measure the potential at the fourth terminal 24 and to determine whether the neutral conductor 14 is connected to the fourth terminal 24 by means of the time curve of the potential at the fourth terminal 24. For example, when the potential at the fourth terminal 24 is constant, this indicates that the neutral conductor 14 is connected to the fourth terminal. In contrast, when the potential has a sinusoidal curve, this indicates that a phase, for example the phase HOT2 of a US network of the "split phase" type, is connected to the fourth terminal 24.

[0034] The control device 41 is preferably designed to switch the controllable switch 45 on when the fourth terminal 24 is connected to the neutral conductor. When the neutral conductor 14 is present, this neutral conductor is preferably connected to the node 53 via the switch 45 .

[0035] The control device 41 is preferably designed to switch the controllable switch 45 to a non-conductive state when the fourth terminal 24 is not connected to the neutral conductor.

[0036] Alternatively, the first value VAL1 can be generated by a user input in that the user predetermines the network to which the rectifier assembly 20 is to be connected.

[0037] It is also possible to measure the potential at the terminal 24 by means of the measuring device 42 and to determine, depending on the potential, whether the fourth terminal 24 is connected to the neutral conductor.

[0038] In a larger overall system, for example a charging infrastructure for an electric vehicle or a hybrid vehicle, there may already be electronics that detect which power supply network 10 is connected to the vehicle. In a corresponding understanding, this information can be used directly to determine the first value VAL1. According to a preferred embodiment, the voltages at all active terminals 21 to 24 are measured in order to reliably determine the connected power supply network.

[0039] If different plugs are used for different power sources 10 to connect the power supply network 10 to the terminals 21 to 24 , information can also be provided by means of an identification signal of the plug used.

[0040] How it works

[0041] Different power sources exist, and the rectifier assembly 20 preferably functions with as large a number of power source variants as possible.

[0042] Figure 2 A power supply network 10, such as is common in Central Europe, is shown, which is designed as a TN system with three phases L1, L2 and L3 and a star point 14' as a neutral conductor, which are ready at the assigned terminals 11, 12, 13. The three phases L1, L2, L3 are supplied by an AC voltage source 17, each of which has a phase difference of 120°. In the embodiment shown, the neutral conductor (N) 14' is grounded and therefore also serves as a protective conductor (PE). This is called a PEN conductor. Many other power sources also have a neutral conductor, but not all power sources have a neutral conductor. In an intermediate station 18 (e.g., a house or a charging station), the PEN terminal 14' is usually divided into a neutral conductor terminal (N) 14 and a protective conductor terminal (PE) 15. Terminals 11, 12, 13, 14, 15 can be connected to terminals 21, 22, 23, 24, 25 to operate a rectifier assembly 20. For this purpose, for example, a plug connector 16 is provided in the vehicle, by means of which the terminals 21 to 25 are directly or indirectly connected to the power supply network 10. The terminals 21 to 24 responsible for the actual current conduction are also referred to as active terminals 21 to 24.

[0043] When such a neutral conductor 14 is present and connected to the fourth terminal 24, it is advantageous to Figure 1 The star point 40 of the power supply 10 is connected to the node 53 via the switch 45. The node 53 is thereby set to the potential of the neutral conductor 14 and the voltage across the capacitors 61, 62, which is, for example, 800 V between the lines 51 and 52, is kept at + / -400 V relative to the potential of the neutral conductor N. As a result, in the event of an insulation fault, the maximum voltage is kept relatively low relative to the potential on the neutral conductor N, and this increases safety. In the case where the neutral conductor 14 is not connected to this node, by contrast, for example, the voltage on the first line 51 could be +600 V relative to the neutral conductor and the voltage on the second line 52 could be -200 V.

[0044] A further advantage is that the leakage current flowing to the protective conductor PE via the capacitors 162 and 163 becomes smaller by connecting the node 53 to the fourth terminal 24. The current at the capacitors 162, 163 is reduced.

[0045] Unlike the power supply network 10 with a neutral conductor, the US power supply network, for example, called "split phase", has a first phase terminal and a second phase terminal, wherein the phase of the second phase terminal is 180° out of phase with respect to the phase of the first phase terminal. The first phase terminal is also referred to as HOT1 and the second phase terminal is referred to as HOT2. A neutral conductor can be provided, but is not always provided. A protective conductor PE is often provided. In a power supply network without a neutral conductor, the first phase terminal HOT1 is connected to one of the terminals 21, 22, 23, or is connected to all three terminals 21, 22, 23 in order to reduce the current through the circuit components 31, 32, 33, and the second phase terminal HOT2 can be connected to the fourth terminal 24. Therefore, instead of a neutral conductor being connected at the fourth terminal 24, a phase terminal HOT2 is connected, which has a phase difference of 180° with respect to HOT1. Tests of charging devices for electric vehicles have shown that the leakage current when the star point 40 is connected to the node 53 by means of the switch 45 is greater than the leakage current when there is no such connection. Specifically, in the case of a connection or when the switch 45 is conducting, a leakage current of the order of magnitude of 100 mA is generated. In the case of a non-conducting switch 45, the leakage current is, on the other hand, significantly less than 10 mA. The residual current switch has, for example, a limit value of 10 mA or 3.5 mA, depending on the respective power supply network 10. It is therefore advantageous to switch the switch 45 to a non-conducting state when no neutral conductor is connected to the fourth terminal 24.

[0046] In the case of the switch 45 switched to be non-conductive, the potential at the node 53 is not fixed at the potential preset by the fourth terminal 24, but the potential can fluctuate. This is called "free floating" in English.

[0047] The controllable switch 45 is preferably designed as an electromechanical switch. For example, a relay can be used for the controllable switch 45. Electromechanical switches have the following advantages: they have a very low resistance in the conducting state. In addition, they have a high isolation resistance in the non-conducting state. Since the controllable switch 45 usually does not change its state during the charging process, fast switching times are not required.

[0048] Figure 3 A vehicle 19 is schematically shown, in which a Figure 1 The first line 51 and the second line 52 are connected to a DC voltage converter (DC / DC converter) 55 so as to supply energy to the DC voltage converter from the intermediate circuit 50. The DC voltage converter 55 is designed as a Buck converter, for example.

[0049] The output end of the DC voltage converter 55 is exemplarily provided with lines 56, 57 and an EMV filter 63. The EMV filter 63 has an X capacitor 161 connected between the lines 56, 57, a Y capacitor 162 between the line 57 and the terminal 25 (protective conductor PE), and a Y capacitor 163 between the line 56 and the terminal 25. Subsequently, the lines 56, 57 are each connected to the line 156 or 157 via an inductor 164 or 165. Subsequently, an X capacitor 166 connected between the lines 156, 157, a Y capacitor 167 between the line 157 and the terminal 25 (protective conductor PE); and a Y capacitor 168 between the line 156 and the terminal 25 are provided. The EMV filter 63 can also be designed to be multi-stage.

[0050] Y capacitors are used to reduce interference voltages which occur relative to the potential at the protective conductor terminal 25. These Y capacitors usually have a specific Figure 1 The X capacitors 61 and 62 have a smaller capacitance. The interference voltage is reduced by causing the leakage current to flow between the protective conductor terminal 25 and the line 56 or 57. The X capacitor is used to buffer the push-pull interference voltage between the terminals 56 and 57. A leakage current from or to the protective conductor PE is generated by the EMC filter 63 .

[0051] Lines 156, 157 are connected to an electrical load 58, in particular to a vehicle battery (traction battery) for a vehicle with an electric drive, or, for example, to a heating device. In this embodiment, no transformer is provided in the illustrated part of the vehicle 19. Usually, a vehicle with a charging device for a traction battery has a transformer, and the transformer leads to an electrical isolation between an external power grid and components of the transformer arranged inside the vehicle. This results in that leakage currents in the transformer inside the vehicle have no effect on the outside of the transformer in the vehicle. Therefore, such leakage currents cannot lead to the triggering of a power grid fuse. In contrast, in the illustrated embodiment, there is no transformer and electrical isolation, and it is therefore advantageous to reduce the leakage current by correspondingly switching the switch 45.

[0052] Figure 4 An embodiment of a circuit arrangement 31 is shown by way of example, which can be used in the same embodiment for circuit arrangements 32, 33. The circuit arrangement is designed in the manner of a Vienna rectifier.

[0053] The first terminal 21 is connected to the node 102 via the coil 101. The node 102 is connected to the point 104 via the diode 103, and the point 104 is connected to the first line 51 via the diode 105. The node 102 is connected to the point 107 via the diode 106, and the point 107 is connected to the second line 52 via the diode 108. A switch 110 is provided between the points 107 and 104. In this embodiment, the switch 110 is designed as a MOSFET, but it can also be other electronic switches (such as IGBTs). The point 107 is connected to the point 113 via the diode 112, and the point 113 is connected to the point 104 via the diode 111. The point 113 is connected to the star point 40. The cathodes of the diodes 103, 105, 106, 108, 111, and 112 are each connected to one side of the first line 51, and the anodes are each connected to one side of the second line 52. The mode of operation of a Vienna rectifier is described, for example, in EP 0 660 498 A2.

[0054] Another possible embodiment of the circuit arrangement 31 , 32 , 33 is, for example, a totem pole circuit, so that the rectifier arrangement operates as a totem pole rectifier.

[0055] Of course, various changes and modifications are possible within the scope of the invention.

[0056] In a real embodiment, further components are preferably present, such as an EMC filter, a power factor regulator, and / or an insulation monitor circuit.

Claims

1. A rectifier assembly (20) for rectifying an AC voltage into a DC voltage, the rectifier assembly (20) having a first terminal (21), a second terminal (22), a third terminal (23) and a fourth terminal (24), the rectifier assembly (20) having an intermediate circuit (50) with a first line (51), a second line (52) and a node (53), the node (53) being connected to the first line (51) via at least one first capacitor (61) and to the second line (52) via at least one second capacitor (62), the first terminal (21), the second terminal (22) and the third terminal (23) being connected to the first line (51) via at least one second capacitor (62), the first terminal (21), the second terminal (22) and the third terminal (23) being connected to the first line (51) via at least one second capacitor (62), the second terminal (22) and the third terminal (23) being connected to the first line (51) via at least one second capacitor (62), the first terminal (21), the second terminal (22) and the third terminal (23) being connected to the second line (52) via at least one second capacitor (62), the first terminal (21), the second terminal (22) and the third terminal (23) being connected to the first line (51) via at least one second capacitor (6 ... , 33) is connected to a star point (40), the fourth terminal (24) is also connected to the star point (40), and the star point (40) is connected to the node (53) via a controllable switch (45), wherein the rectifier component has a control device (41), the control device (41) is designed to influence the controllable switch (45), the control device (41) is designed to switch the controllable switch (45) to conduction under the condition that the fourth terminal (24) is connected to the neutral conductor (14), and the control device (41) is designed to switch the controllable switch (45) to non-conduction under the condition that the fourth terminal (24) is not connected to the neutral conductor (14).

2. The rectifier component (20) according to claim 1, wherein the circuit components (31, 32, 33) are each designed to enable a current to flow between the circuit component (31, 32, 33) on the one hand and the first line (51) and / or the second line (52) on the other hand.

3. The rectifier assembly (20) according to claim 1 or 2, wherein the first terminal (21), the second terminal (22) and the third terminal (23) of the rectifier assembly (20) are configured to be connected to three phases of the power supply network (10) respectively, and the fourth terminal (24) of the rectifier assembly (20) is configured to be connected to a neutral connector of the power supply network (10).

4. The rectifier assembly (20) according to claim 1, wherein the control device (41) is designed to switch the controllable switch (45) at the connected power supply network (10) to either be conductive or non-conductive during the entire rectification process.

5. A rectifier assembly (20) according to claim 4, wherein the control device (41) is designed to generate a first value (VAL1), which first value (VAL1) depends on the power supply network (10), which is connected to the first terminal (21), the second terminal (22), the third terminal (23) and the fourth terminal (24), and the control device (41) is designed to influence the controllable switch (45) depending on the first value (VAL1).

6. The rectifier arrangement (20) according to claim 5, wherein the control device (41) is designed to generate the first value (VAL1) by checking whether the fourth terminal (24) is connected to a neutral conductor.

7. The rectifier assembly (20) according to claim 5, wherein the control device (41) is designed to measure the potential at the fourth terminal (24) and to determine whether the neutral conductor (14) is connected to the fourth terminal (24) by means of the time curve of the potential at the fourth terminal (24).

8. The rectifier assembly (20) according to any one of claims 1, 2, 4, 6 and 7, comprising a mains filter (63) which enables leakage current.

9. The rectifier assembly (20) according to any one of claims 1, 2, 4, 6 and 7, wherein the controllable switch (45) is designed as an electromechanical switch.

10. The rectifier assembly (20) according to any one of claims 1, 2, 4, 6 and 7, wherein the controllable switch (45) is designed as a relay.

11. A vehicle (19) which is designed as an electric vehicle or a hybrid vehicle and which has a rectifier arrangement (20) according to one of the preceding claims.

12. The vehicle (19) according to claim 11, comprising a plug connector (16) for connecting a charging cable for the vehicle (19), and wherein an electrical coupling is at least temporarily present between the terminals at the plug connector (16) and the rectifier assembly (20).

Images