Electronic device and method for manufacturing an electronic device

Abstract

An electronic device has a power electronic device and an output that can be coupled to a power grid. The power electronic device is coupled to the output via busbars. An active electromagnetic compatibility (EMC) filter is designed to suppress common-mode interference from the power electronic device. The active EMC filter is coupled to the busbars between the power electronic device and the output via a decoupling device. The decoupling device can reduce the influence of a power grid inductance on the EMC filter.

Description

[0001] The present invention relates to an electronic device and a method for manufacturing an electronic device. State of the art

[0002] To improve electromagnetic compatibility (EMC), the influence of electromagnetic fields must be reduced. Therefore, EMC filters are used in power electronic devices, such as inverters or rectifiers, to suppress the electromagnetic interference generated by switched semiconductors.

[0003] EMC filters typically consist of a combination of purely passive components, such as capacitors and common-mode or differential-mode chokes, as well as active filters that include transistors or operational amplifiers. Active EMC filters can be configured as feedforward or feedback filters. The feedback topologies can be divided into four groups: voltage sensing voltage injection (VSVI), voltage sensing current injection (VSCI), current sensing voltage injection (CSVI), and current sensing current injection (CSCI).

[0004] In the VSCI topology, the active filter circuit can be connected directly to the DC power rails, for example, in the rectifier or inverter.

[0005] Alternatively, the active filter circuit can be connected to the AC power rails, for example in an on-board charger.

[0006] The VSCI topology of the active EMC filter is a feedback control loop and therefore tends to oscillate, which can result in the loss of the actual function.

[0007] The impedance conditions of the supply voltage network to which the power electronic component containing the active EMC filter is connected influence the stability of the control loop. For example, inverters or rectifiers in electric cars are connected to a high-voltage battery. On-board chargers are connected to the public grid on one side and to the high-voltage battery on the other. The active EMC filters enable the filtering of common-mode interference from the power electronic component, whereby the common-mode impedances of the public AC grid or the electric vehicle's electrical system are relevant for the stability of the feedback control loop.

[0008] The stability of the VSCI topology reacts very sensitively to changes in the common-mode impedance of the grid, so stability can only be guaranteed within a limited common-mode impedance range. This can, for example, lead to the active EMC filter not functioning oscillation-free in all vehicle variants in which the power electronic components are installed. Accordingly, in on-board chargers, the active EMC filter does not function oscillation-free in all AC networks or wallboxes. Disclosure of the invention

[0009] The invention provides an electronic device and a method for manufacturing an electronic device having the features of the independent claims.

[0010] Preferred embodiments are the subject of the respective subclaims.

[0011] According to a first aspect, the invention relates to an electronic device having a power electronic device and having an output that can be coupled to a power grid. The power electronic device is coupled to the output via busbars. An active EMC filter is designed to suppress common-mode interference from the power electronic device. The active EMC filter is coupled to the busbars between the power electronic device and the output via a decoupling device. The decoupling device can reduce the influence of an inductance of the power grid on the EMC filter.

[0012] According to a second aspect, the invention relates to a method for manufacturing an electronic device. A power electronic device and an output are provided, wherein the output can be coupled to a supply network. The power electronic device is coupled to the output via busbars. Furthermore, an active EMC filter is provided, which is designed to suppress common-mode interference of the power electronic device. A decoupling device is arranged, wherein the active EMC filter is coupled to the busbars between the power electronic device and the output via the decoupling device. The decoupling device is designed to reduce the influence of an inductance of the supply network on the EMC filter. Advantages of the invention

[0013] The use of the decoupling device makes it possible to decouple the active EMC filter to suppress common-mode interference.

[0014] For this purpose, a preferably passive decoupling device is connected between the active EMC filter (preferably in VSCI topology) and the busbars of the power electronic device so that the influence of the common-mode impedance of the supply network is reduced in a desired frequency range.

[0015] This extends the application range of the active EMC filter to supply networks with unknown or widely varying common-mode impedances.

[0016] The influence of the common-mode impedance of the supply network connected to the power electronic component (e.g., a high-voltage vehicle electrical system or a public AC network) on the tendency of the feedback control loop of the active EMC filter to oscillate can be reduced. Depending on the conditions and variance of the common-mode impedance of the supply network, the invention makes the use of an active EMC filter possible.

[0017] According to a further embodiment of the electronic device, the decoupling device comprises at least one resistor, which forms an LR element with an inductance of the supply network, wherein the at least one resistor reduces the influence of the inductance of the supply network in a first frequency range. At low frequencies, the inductance of the supply network is reduced to prevent excessive oscillation behavior.

[0018] According to a further embodiment of the electronic device, the decoupling device comprises at least one capacitor connected in parallel with the resistor, wherein the at least one capacitor reduces the influence of the resistor in a second frequency range. At higher frequencies, the active EMC filter is intended to suppress interference, so that the active EMC filter is no longer decoupling.

[0019] According to a further embodiment of the electronic device, the at least one resistor and the at least one capacitor form cascading RC elements. This allows frequency dependencies of the decoupling to be adjusted.

[0020] According to a further embodiment of the electronic device, at least one passive EMC filter is coupled to the busbars between the power electronic device and the active EMC filter and / or between the output and the active EMC filter. This allows for further suppression of interference.

[0021] According to a further embodiment of the electronic device, the active EMC filter comprises a high-pass filter configured to filter an electrical current tapped from the busbars. The active EMC filter further comprises an active amplifier configured to amplify the filtered current. The active EMC filter further comprises a coupling structure configured to couple the filtered and amplified current to the busbars.

[0022] According to a further embodiment of the electronic device, the coupling structure comprises at least one capacitor.

[0023] According to a further embodiment, the electronic device is a rectifier or inverter for an electric vehicle.

[0024] According to a further embodiment, the electronic device is an on-board charger for an electric vehicle.

[0025] Further advantages, features and details of the invention will become apparent from the following description, in which various embodiments are described in detail with reference to the drawings. Short description of the drawings

[0026] They show: Fig. 1 is a schematic diagram of an electronic device according to an embodiment of the invention; Fig. 2 a schematic diagram of an active EMC filter for use in the Fig. 1 shown electronic device; Fig. 3 is a schematic diagram of an electronic device according to another embodiment of the invention; Fig. 4 a schematic diagram of an active EMC filter for use in the Fig. 3 shown electronic device; Fig. 5 shows a component of a decoupling device for use in an electronic device according to an embodiment of the invention; Fig. 6 shows a further component of a decoupling device for use in an electronic device according to an embodiment of the invention; Fig. 7 is a schematic diagram of an electronic device for explaining current flows; Fig. 8 an equivalent circuit diagram of the Fig. 7 shown circuit diagram; Fig. 9 an equivalent circuit diagram of the Fig. 8 shown circuit diagram; Fig. 10 an exemplary representation of a frequency-dependent loop gain in an active EMC filter; Fig. 11 an equivalent circuit diagram of the Fig. 8 shown circuit diagram; and Fig. 12 is a schematic flow diagram of a method for manufacturing an electronic device.

[0027] In all figures, identical or functionally equivalent elements and devices are provided with the same reference numerals. The numbering of process steps serves the purpose of clarity and is generally not intended to imply a specific chronological order. In particular, several process steps can be performed simultaneously. Description of the embodiments

[0028] Fig. 1 shows a schematic diagram of an electronic device 100. The electronic device 100 may be a rectifier or inverter for an electric vehicle or an on-board charger for an electric vehicle.

[0029] The electronic device 100 comprises a power electronic device 1 (power electronics) and an output 2. The output 2 can be coupled to a supply network 7.

[0030] The power electronic device 1 is coupled to the output 2 via two busbars 81, 82 (voltage supply lines).

[0031] An active EMC filter 3a is designed to suppress common-mode interference of the power electronic device 1. The active EMC filter 3a is coupled via a decoupling device 4 to the busbars 81, 82 between the power electronic device 1 and the output 2.

[0032] The decoupling device 4 can reduce the influence of an inductance of the supply network 7 on the EMC filter 3a.

[0033] The active EMC filter 3a has a high-pass filter 31a, which filters an electrical current tapped from the busbars 81, 82. The active EMC filter 3a further comprises an active amplifier 32, which amplifies the filtered current. Finally, the active EMC filter 3a comprises a coupling structure 33a, which couples the filtered and amplified current to the busbars 81, 82.

[0034] With the help of the high-pass filter 31, the common-mode interference is measured and the signal inverted and amplified by the active amplifier 32 is coupled back into the busbars 81, 82 via feed capacitors of the coupling structure 33a.

[0035] Furthermore, a first passive EMC filter 6 is coupled between the power electronic device 1 and the active EMC filter 3a to the busbars 81, 82. Another passive EMC filter 5 is coupled between the output 2 and the active EMC filter 3a. The invention is not limited thereto. In particular, the first passive EMC filter 6 can be optional and / or the second passive EMC filter 5 can be optional.

[0036] Fig. 2 shows a schematic diagram of an active EMC filter 3a for use in the Fig. 1. The high-pass filter 31a comprises a first capacitor C1 for the first power rail, a second capacitor C2 for the second power rail, and a resistor R1 connected to ground. The active amplifier 32 is an operational amplifier. The coupling structure 33a comprises a first capacitor C4 for the first power rail and a second capacitor C3 for the second power rail.

[0037] Fig. 3 shows a schematic diagram of another electronic device 200. In contrast to the Fig. The electronic device 100 shown in Figure 1 comprises the Fig. 3, the electronic device 200 has four busbars 91 to 94.

[0038] Fig. 4 shows a schematic diagram of an active EMC filter 3b for use in the Fig. 3 shown electronic device 200. In contrast to Fig. 2, the high-pass filter 31b now comprises first to fourth capacitors C1 to C4 for the first to fourth power rails 91 to 94, and the coupling structure 33b also comprises first to fourth capacitors C5 to C8 for the first to fourth power rails 91 to 94.

[0039] Fig. Figure 5 shows a component 41 of a decoupling device 4 for use in an electronic device 100, 200. Component 41 can be inserted into one of the connecting lines between the active EMC filter 3a, 3b and the corresponding busbar 81, 82, 91-94. Component 41 is an RC element with a resistor R1' and a capacitor C1' connected in parallel.

[0040] Resistor R1' forms an LR element with the inductance of supply network 7. In a first, low frequency range, resistor R' reduces the influence of the inductance of supply network 7. The parallel-connected capacitor C1' reduces the influence of resistor R' in a second, higher frequency range.

[0041] Fig. 6 shows a further component 42 of a decoupling device 4 for use in an electronic device 100, 200. The component 42 can also be introduced into one of the connecting lines between the active EMC filter 3a, 3b and the corresponding busbar 81, 82, 91-94.

[0042] Component 42 is designed as a cascading RC element with three resistors R1", R2", R3", and two capacitors C1", C2". By using chained or cascading RC elements, the effective frequency response of the resistors R1", R2" in component 42 can be adjusted more precisely, for example by setting multiple steps or a flatter or steeper roll-off at higher frequencies.

[0043] Fig. Figure 7 shows a schematic circuit diagram of an electronic device 100 for explaining current flows, with the decoupling device 4 not shown. Common-mode interference currents generated in the power electronic device 1 flow in the same direction in the busbars 81, 82 toward the supply network 7 and via parasitic capacitances or a galvanic connection to ground. Due to this common direction, a current I flows. CM / 2 (with two supply lines) or I CM / 4 (with four supply lines) per busbar 81, 82, 91-94.

[0044] Fig. 8 shows an equivalent circuit of the Fig. 7. For this purpose, the busbars 81, 82, 91-94 are virtually short-circuited, so that there is only one conductor 83 in which a current with strength I CM flows. Impedances Z1 and Z2 in supply network 7 are now parallel. A common-mode impedance Z Load summarizes the impedance of the optional first passive EMC filter 5 and the supply network 7. Another common-mode impedance Z Source is defined in the direction of the power electronic device 1.

[0045] Fig. 9 shows an equivalent circuit of the Fig. 8. At the connection point of the active EMC filter 3a, Z Source and Z Load parallel, so that these have been combined.

[0046] For the stability analysis, the loop gain (LG) of a feedback loop 10 is calculated. A minimum phase margin can now be required at a loop gain of 1, for example, 45°. This means that when passing through the 0 dB point (which corresponds to a loop gain of 1), a maximum phase shift of -135° to 135° is tolerable to achieve a sufficiently decaying behavior of the circuit.

[0047] Fig. Figure 10 shows an exemplary representation of a frequency-dependent loop gain LG in an active EMC filter 3a, 3b as a function of the frequency f. The point 11 at 0 dB is marked.

[0048] The high-pass characteristic, ie the increasing loop gain at higher frequencies, results from the way in which the active EMC filter 3a, 3b is connected to the busbars 81, 82, 91-94. The coupling of the compensation current is carried out via Fig. 2 and Fig. 4 shown capacitors are realized, which connect the active EMC filter 3a, 3b with the busbars 81, 82, 91-94.

[0049] Fig. 11 shows an equivalent circuit of the Fig. 8. To determine the influence of the impedance Z Load To clarify the supply network 7, the phase shifts of the individual network elements are shown. Assuming a 180° phase shift by the inverting active amplifier 32, only a maximum of 135° phase shift is possible via the voltage divider, which consists of the feed-in capacitance and the parallel connection of Z load and Z Sourceacceptable to obtain 45° phase margin. Assuming that ZLoad <ZSource, The voltage divider therefore only consists of the feed-in capacitance and Z load . For highly inductive network impedances Z load This results in a second-order high-pass filter. Depending on the feed capacitance and the inductance of the network, phase shifts of up to 180° can occur in the frequency range of the 0 dB point, which can lead to a phase margin of 0° (-180° + 180°) and consequently an unstable system.

[0050] Such instabilities are prevented by the decoupling device 4. The decoupling device 4 has the task of significantly reducing the inductive behavior of the network impedance. By inserting a series resistor to the network inductance (as in the Fig. 5 and Fig. 6) results in an LR series network which, depending on the resistance value, is only weakly inductive in the frequency range of the 0 dB point of the loop gain.

[0051] Advantageously, this significantly reduces the maximum phase shift of the high-pass filter, consisting of the input capacitance and the resulting LR element. Furthermore, by decoupling the mains impedance using the resistor, the frequency shift of the 0 dB point of the loop gain can be reduced when the mains impedance changes, making the desired common-mode rejection more predictable.

[0052] The 0 dB point of the loop gain is usually well below 150 kHz, whereby from 150 kHz onwards a high loop gain is aimed for to suppress common-mode interference.

[0053] In order not to deteriorate the insertion loss of the active EMC filter 3a, 3b above 150 kHz, the Fig. 5 and Fig. The decoupling resistor can be short-circuited using at least one capacitor shown in Figure 6. During design, it is preferable to ensure that, starting at 150 kHz, the impedance of the decoupling device 4 is much smaller than the impedance of the supply network 7 in order to prevent a reduction in insertion loss.

[0054] Fig. 12 shows a schematic flow diagram of a method for manufacturing an electronic device, in particular one of the devices described in Fig. 1 or Fig. 3 shown electronic devices 100, 300.

[0055] In a first step S1, a power electronic device 1 and an output 2 are provided, wherein the output 2 is connectable to a power grid 7. The power electronic device 1 is coupled to the output 2 via busbars 81, 82; 91-94. Furthermore, an active EMC filter 3a, 3b is provided, which is designed to suppress common-mode interference of the power electronic device 1.

[0056] A decoupling device 4 is arranged, wherein the active EMC filter 3a, 3b is coupled via the decoupling device 4 to the busbars 81, 82; 91-94 between the power electronic device 1 and the output 2. The decoupling device 4 is designed to reduce the influence of an inductance of the supply network 7 on the EMC filter 3a, 3b.

[0057] The decoupling device 4 can have at least one resistor which forms an LR element with an inductance of the supply network 7, wherein the at least one resistor reduces the influence of the inductance of the supply network 7 in a first frequency range.

[0058] The decoupling device 4 can further comprise at least one capacitor connected in parallel with the resistor, wherein the at least one capacitor reduces the influence of the resistor in a second frequency range. The at least one resistor and the at least one capacitor can form cascading RC elements.

[0059] Optionally, a passive EMC filter 5, 6 can be coupled between the power electronic device 1 and the active EMC filter 3 and / or between the output 2 and the active EMC filter 3 with the busbars 81, 82; 91-94.

[0060] The active EMC filter 3 can have a high-pass filter 31, which is designed to filter an electrical current tapped from the busbars 81, 82; 91-94. The active EMC filter 3 optionally further comprises an active amplifier 32, which is designed to amplify the filtered current. The active EMC filter 3 optionally further comprises a coupling structure 33, which is designed to couple the filtered and amplified current to the busbars 81, 82; 91-94. The coupling structure 33 can comprise at least one capacitor.

Claims

[1] Electronic device (100; 200), comprising: a power electronic device (1); an output (2) which can be coupled to a supply network (7), wherein the power electronic device (1) is coupled to the output (2) via busbars (81, 82; 91-94); an active electromagnetic compatibility, EMC, filter (3a, 3b) which is designed to suppress common-mode interference of the power electronic device (1); and a decoupling device (4), wherein the active EMC filter (3a, 3b) is coupled via the decoupling device (4) to the busbars (81, 82; 91-94) between the power electronic device (1) and the output (2); wherein the decoupling device (4) is designed to reduce an influence of an inductance of the supply network (7) on the EMC filter (3a, 3b). [2] Electronic device (100; 200) according to claim 1, wherein the decoupling device (4) has at least one resistor which forms an LR element with an inductance of the supply network (7), wherein the at least one resistor reduces the influence of the inductance of the supply network (7) in a first frequency range. [3] Electronic device (100; 200) according to claim 2, wherein the decoupling device (4) comprises at least one capacitor connected in parallel with the resistor, wherein the at least one capacitor reduces the influence of the resistor in a second frequency range. [4] The electronic device (100; 200) of claim 3, wherein the at least one resistor and the at least one capacitor form cascading RC elements. [5] Electronic device (100; 200) according to one of the preceding claims, wherein at least one passive EMC filter (5, 6) is coupled to the busbars (81, 82; 91-94) between the power electronic device (1) and the active EMC filter (3a, 3b) and / or between the output (2) and the active EMC filter (3a, 3b). [6] Electronic device (100; 200) according to one of the preceding claims, wherein the active EMC filter (3a, 3b) comprises: a high-pass filter (31a, 31b) which is designed to filter an electrical current tapped from the busbars (81, 82; 91-94); an active amplifier (32) configured to amplify the filtered current; and a coupling structure (33a, 33b) which is designed to couple the filtered and amplified current to the busbars (81, 82; 91-94). [7] Electronic device (100; 200) according to one of the preceding claims, wherein the coupling structure (33a, 33b) comprises at least one capacitor. [8] Electronic device (100; 200) according to one of the preceding claims, wherein the device (100; 200) is a rectifier or inverter for an electric vehicle. [9] Electronic device (100; 200) according to one of the preceding claims, wherein the device (100; 200) is an on-board charger for an electric vehicle. [10] A method for manufacturing an electronic device (100; 200), comprising the steps of: Providing (S 1) a power electronic device (1), an output (2) which can be coupled to a supply network (7), wherein the power electronic device (1) is coupled to the output (2) via busbars (81, 82; 91-94), and an active electromagnetic compatibility, EMC, filter (3a, 3b) which is designed to suppress common-mode interference of the power electronic device (1); and Arranging (S2) a decoupling device (4), wherein the active EMC filter (3a, 3b) is coupled via the decoupling device (4) to the busbars (81, 82; 91-94) between the power electronic device (1) and the output (2); wherein the decoupling device (4) is designed to reduce an influence of an inductance of the supply network (7) on the EMC filter (3a, 3b).

Images