Power module, power converter and electric drive for vehicle

Abstract

Provided is a power module (1). Comprising at least one arrangement (2, 2 ') of a plurality of dies (2a-h), each die forming a transistor having a switching path, each die (2a-h) having a first terminal (3), a second terminal (4) and a control terminal (5), the switching path being formed between the first terminal (3) and the second terminal (4) and being switchable according to a voltage between the control terminal (5) and the second terminal (4), the transistors are connected in parallel via a first connection (3) connected to one another and a second connection (4) connected to one another, the at least one arrangement (2, 2 ') comprises a shielding structure (13) at least partially covering at least two of the dies (2a-h), the shielding structure (13) comprising or consisting of one or more materials selected from the group consisting of nickel-zinc-based ferrites, nickel-iron soft ferromagnetic alloys and electrical steel.

Description

Field of the Invention

[0001] The present invention relates to a power module comprising at least one arrangement of a plurality of dies, each die forming a transistor having a switching path, each die having a first terminal, a second terminal and a control terminal, the switching path being formed between the first terminal and the second terminal and being switchable according to a voltage between the control terminal and the second terminal, the transistors being connected in parallel by the first terminals connected to each other and the second terminals connected to each other.

[0002] Furthermore, the present invention relates to a power converter and an electric drive for a means of transportation, such as for a vehicle or a bicycle. Background Art

[0003] I. Kovacevic-Badstuebner, U. Grossner, D. Popescu and B. Popescu, "Transient stability analysis of discrete and multi-chip power semiconductor packages", published in the 33rd International Symposium on Power Semiconductor Devices & ICs (ISPSD) 2021, 2021, pp. 391 - 394, disclose parallel power devices based on 650V silicon carbide power MOSFETs and discuss the problem of high-frequency oscillations occurring during fast switching transients.

[0004] With the increasing power demand provided by traction inverters for electric means of transportation, it has become necessary to connect multiple dies in parallel in order to cope with the corresponding current and loss densities. However, connecting the dies in parallel results in a very complex resonant system with unique feedback loops. In the VHF frequency band, especially above 100 MHz, corresponding oscillations can be expected and different fault mechanisms can be triggered within the structure of the control terminals of the dies.

[0005] In order to reduce the corresponding coupling in such feedback loops, I. Kasko, S. E. Berberich, M. Spang and S. Oehling proposed in "Silicon Carbide (SiC) MOS Power Modules in Direct Bonded Die Technology and Some Challenges in Their Implementation" (published in the 32nd International Symposium on Power Semiconductor Devices & ICs (ISPSD) 2020, 2020, pp. 364 - 367) to increase the internal gate resistance of parallel silicon carbide MOS. However, the increase in the resistance at the control terminals unfavorably reduces the achievable switching speed of the power module and requires internal modifications to the dies. In addition, integrating separate gate pre-resistors increases the complexity of the module assembly process as well as the footprint of the power module, thus reducing the reliability and power density of the power converter.

[0006] Furthermore, it is known from DE 10 201 9 202 728 A1 that a plate-like structure made of a conductive material is provided to a half-bridge of a semiconductor switch. The plate-like structure is mounted at a distance from the half-bridge for reducing the intermediate circuit inductance by inducing eddy currents in the plate-like structure.

[0007] Furthermore, US 2003 / 0011057 A1 discloses a semiconductor device having semiconductor elements and bonding wires connecting the semiconductor elements to electrodes. A sheet member is disposed above the bonding wires. A sealing resin member covers the electrodes, the semiconductor elements, the bonding wires and embeds the sheet member. The sheet member can reduce the vibration of the sealing resin member. SUMMARY OF THE INVENTION

[0008] The object of the present invention is to improve the operation of a power module having parallel dies, particularly in terms of reducing VHF oscillations. According to the present invention, this object is solved by a power module as initially described, wherein at least one arrangement includes a shielding structure that at least partially covers at least two of the dies, the shielding structure comprising one material or a plurality of materials or consisting of one material or a plurality of materials selected from the group consisting of nickel-zinc-based ferrites, nickel-iron soft ferromagnetic alloys, and electrical steel.

[0009] The power module according to the present invention includes at least one arrangement of a plurality of dies. Each die forms a transistor having a switching path. Each die has a first terminal, a second terminal, and a control terminal. The switching path is formed between the first terminal and the second terminal. The switching path can be switched according to the voltage between the control terminal and the second terminal. The transistors are connected in parallel by the first terminals connected to each other and the second terminals connected to each other. The at least one arrangement further includes a shielding structure. The shielding structure at least partially covers at least two of the dies. The shielding structure comprises one material or a plurality of materials or consists of one material or a plurality of materials. The material is selected from the group. The group consists of nickel-zinc-based ferrites, nickel-iron soft ferromagnetic alloys, and electrical steel.

[0010] The present invention is based on the following considerations: By providing a shielding structure to reduce VHF oscillations caused by inductive feedback loops when the dies are connected in parallel, so as to affect the magnetic coupling between the first terminal and the second terminal and the control terminal loop and / or by attenuating the feedback loop. Among them, nickel-zinc-based ferrites provide suitable high-frequency loss characteristics for attenuating the feedback loop. In addition, it has been observed that a shielding structure made of or containing nickel-iron soft ferromagnetic alloy and / or electrical steel can also significantly reduce the VHF oscillation amplitude, although these materials are not usually known for their high-frequency characteristics. Advantageously, the power module according to the present invention allows for reducing VHF oscillations, particularly without affecting the internal control terminal resistance and without reducing the maximum switching speed of the power module.

[0011] This set can be limited to consisting of only nickel-zinc-based ferrites or only nickel-iron soft ferromagnetic alloys or only electrical steel or only nickel-zinc-based ferrites and nickel-iron soft ferromagnetic alloys or only nickel-zinc-based ferrites and electrical steel or only nickel-iron soft ferromagnetic alloys and electrical steel.

[0012] The number of dies can be at least two, preferably at least four, more preferably at least six. The transistor can be an insulated gate bipolar transistor (IGBT). In this case, the first terminal can be the collector terminal, the second terminal can be the emitter terminal, and the control terminal can be the gate terminal. Optionally, the transistor can be a metal oxide semiconductor field effect transistor (MOSFET), preferably based on silicon carbide (SiC), or a high electron mobility transistor (HEMT), particularly based on gallium nitride (GaN). Regarding MOSFETs and HEMTs, the first terminal can be the drain terminal, the second terminal can be the source terminal, and the control terminal can be the gate terminal. Preferably, the transistor is configured to block a voltage of at least 400 V, preferably at least 800 V, more preferably at least 1200 V on the switching path. However, the present invention can also be applied to low-voltage power modules, such as in a 48-volt system, where the transistor is configured to block at least 50 V of voltage.

[0013] Specifically, the electrical connection between the dies can form a resonant circuit having one or more resonant frequencies of at least 100 MHz and a feedback loop that forms an inductive coupling between the second terminal on one hand and the first terminal and / or the control terminal on the other hand. Then, the shielding structure can be configured to reduce the inductive coupling. Thus, the shielding structure can be particularly suitable for reducing the inductive coupling between the feedback loop (output loop) connected to the first and second terminals and / or the feedback loop (input loop) connected to the control and second terminals within the above frequency range. In particular, the at least resonant frequency can be between 100 MHz and 1 GHz.

[0014] Regarding the nickel-zinc-based ferrite, it preferably has a complex magnetic permeability with a real part and an imaginary part. The complex magnetic permeability of the nickel-zinc-based ferrite μ can thus be expressed as μ = μ0·(μ′ r - j·μ′′ r ), where μ0 represents the magnetic permeability of free space, μ′ r represents the real part of the relative magnetic permeability, μ′′ r represents the imaginary part of the relative magnetic permeability, and j represents the imaginary unit.

[0015] Ideally, within a frequency range between 10 MHz and 1 GHz, preferably between 100 MHz and 1 GHz, there is a maximum value of the imaginary part. The maximum value of the imaginary part is within or close to the expected oscillation frequency, providing a high attenuation effect on the oscillation, such that a nickel-zinc based ferrite having a maximum value within this range is advantageous.

[0016] Alternatively or additionally, at a frequency of 100 MHz, preferably 50 MHz, more preferably 10 MHz, the real part of the complex magnetic permeability decreases compared to its value for a frequency close to zero. In particular, the real part decreases by a factor of 2, preferably by a factor of 10. It has been observed that due to the corresponding increase in the magnetic flux linkage and the increase in feedback, relatively high real part values may even amplify the oscillation. Therefore, a nickel-zinc based ferrite is preferably selected, the real part of whose complex magnetic permeability has decreased at the above frequencies. It should be noted that according to Snoek's law, there is a relationship between the real part of the complex permeability of the ferrite and the corner frequency, i.e., the higher the real part of the complex permeability, the lower the corner frequency. It has been found that for frequencies close to zero permeability, a suitable value of the real part of the complex number is below 300, preferably 100, more preferably 30. In summary, it is desirable to select a nickel-zinc based ferrite that has a high imaginary part value of the complex magnetic permeability and at the same time has a low real part value of the complex magnetic permeability in order to provide high attenuation efficiency.

[0017] The soft magnetic nickel-iron alloy can be a high permeability alloy or a permalloy. The nickel-iron alloy can contain A wt.% nickel, B wt.% iron, and C wt.% metal, where A + B + C ≤ 100, 75 ≤ A ≤ 80, 15 ≤ B ≤ 20, 2 ≤ C ≤ 5, and the metal is one or more metals selected from copper, chromium, molybdenum, and cobalt. Such alloys are commercially available but are generally not used for high-frequency applications or EMI applications.

[0018] The electrical steel can be especially non-grain-oriented silicon steel. The electrical steel can comply with EN 10106:2015 or EN10107:2014. This steel is generally used as a sheet in transformer or motor applications but is not used in applications involving the VHF range or higher ranges.

[0019] Generally, the shielding structure can be plate-shaped. That is, the shielding structure can cover at least two dies in two spatial directions and can have a low thickness in the vertical spatial direction. Generally, the shielding structure has a thickness of less than 5 mm, preferably less than 2 mm, more preferably less than 1 mm, or even less than 0.5 mm.

[0020] Typically, at least one arrangement may also include a conductive first pad to which the second terminal is connected. The power module may further include a conductive second pad to which the first terminal is connected, and / or a conductive trace to which the control terminal is connected, and / or another conductive pad of the power module to which the other pad of the die's Kelvin terminal is connected. Of course, the die may have additional terminals, such as terminals for current sensing.

[0021] According to a first preferred design of the power module according to the invention, the shielding structure does not cover the die with the minimum distance from the first pad. In this case, the die close to the first pad may not be covered because it forms only a relatively small feedback loop with respect to the second pad or the trace. Alternatively or additionally, the shielding structure does not cover the die with the minimum distance from the other pad. In this case, the die close to the other pad may not be covered because it forms only a relatively small feedback loop to the trace. By not covering the selected die, the material for the shielding structure can be advantageously saved.

[0022] According to a second preferred design of the power module according to the invention, the shielding structure at least partially covers each die. By covering all the dies, a high attenuation efficiency can be achieved.

[0023] Regarding the power module according to the invention, it is further preferred that the shielding structure completely covers at least two dies. By completely covering the corresponding dies, a high attenuation efficiency can also be achieved.

[0024] The power module according to the invention may further include a carrier on which the dies are mounted, and at least two dies are arranged between the carrier and the shielding structure. The carrier may be made of ceramic, in which a direct bonded copper substrate (DBC), a direct bonded aluminum substrate (DBA), or an active metal brazed substrate (AMB) is realized. Alternatively, the carrier may be made of metal with a dielectric coating thereon. Such a carrier can realize an insulated metal substrate (IMS).

[0025] In addition, the power module according to the invention may further include a single body formed of an electrically insulating molding material, which covers the dies and / or the electrical connections between the dies, such as wire bonds. The body can be used together with the carrier by overmolding. In addition, the carrier may be omitted, such that the body covers or embeds the dies and the electrical connections. Thus, a transfer molded lead frame (TML) design can be realized. The body may further cover or embed the pads.

[0026] Preferably, the body is embedded in the shielding structure. Thus, the position of the shielding structure can be fixed relative to the dies or the connections respectively, so as to provide stable attenuation characteristics.

[0027] At least one arrangement may also include a support structure for mounting a shielding structure. The support structure can provide a defined distance between the die and the shielding structure, where the shielding structure is positioned at a location where good attenuation characteristics can be achieved. It should be noted that the choice of the distance depends on various design details of the power module and should be based on simulation or experimentation.

[0028] Specifically, the support structure can be mounted on a carrier. Additionally, the support structure can be a frame on which the shielding structure is arranged, or a plurality of domes, each dome selectively supporting the shielding structure. Further, the support structure can be electrically connected to the shielding structure. Thus, the support structure can be implemented with different geometries, which helps its application to highly diverse power module designs.

[0029] Moreover, the support structure can be electrically insulating. Thereby, an electrical connection between the shielding structure and other conductive components can be avoided. Nevertheless, the shielding structure can be connected, for example, via the support structure to a suitable voltage potential of the power module in order to additionally shield the electrical flux generated by the switching operation of the die to reduce electromagnetic emissions.

[0030] Preferably, a first arrangement and a second arrangement are provided, with the first terminal of the first arrangement connected to the second terminal of the second arrangement so as to form a half-bridge.

[0031] According to another aspect, the present invention relates to a power module including at least one arrangement of a plurality of dies, each die forming a transistor having a switching path, each die having a first terminal, a second terminal, and a control terminal, the switching path being formed between the first terminal and the second terminal and being switchable according to the voltage between the control terminal and the second terminal, the transistors being connected in parallel by the first terminals connected to each other and the second terminals connected to each other, wherein the arrangement includes a shielding structure at least partially covering at least two of the dies, wherein the electrical connections between the dies form a resonant circuit and a feedback loop, the resonant circuit having one or more resonant frequencies of at least 100 MHz, the feedback loop forming an inductive coupling between the second terminal on one hand and the first terminal and / or the control terminal on the other hand, and the shielding structure being configured to reduce the inductive coupling. All of the above statements similarly apply to this aspect, such that the corresponding advantages can also be achieved.

[0032] The present invention also relates to a power converter including: a DC port for a DC voltage; an AC port having a plurality of phase conductors for an AC voltage; and a power section including a plurality of switching elements, the plurality of switching elements being interconnected to a half-bridge for each phase conductor, each half-bridge being connected between the DC port and each phase conductor, each phase conductor being connected to a center tap between the switching elements of one of the half-bridges; wherein each switching element or each half-bridge is formed by a power module according to the present invention.

[0033] The half-bridge can be connected to two lines of the DC port. Of course, there are other layouts for connecting the half-bridge to the DC port.

[0034] The invention also relates to an electric drive for a vehicle (such as a motor vehicle or a bicycle), which includes a motor configured to propel the vehicle and a power converter according to the invention. The motor is connected to the AC port of the power converter for supplying an AC voltage to the motor. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Further details and advantages of the invention are disclosed below, with reference to the drawings, which schematically show:

[0036] Figure 1 is a partial top view of a first embodiment of a power module according to the invention;

[0037] Figure 2 is a top view of the power module according to the first embodiment;

[0038] Figure 3 is a cross-sectional view of the power module according to the first embodiment;

[0039] Figure 4 is a top view of a second embodiment of a power module according to the invention;

[0040] Figure 5 is a graph showing the variation of the gate-source voltage, drain-source voltage and drain-source current of a power module without a shielding structure over time and a graph showing the variation of the gate-source voltage with frequency;

[0041] Figure 6 is a graph showing the variation of the gate-source voltage, drain-source voltage and drain-source current of a power module with a shielding structure made of manganese-zinc ferrite over time and a graph showing the variation of the gate-source voltage with frequency;

[0042] Figure 7 is a graph showing the variation of the gate-source voltage, drain-source voltage and drain-source current of a power supply module with a shielding structure made of nickel-iron soft ferromagnetic alloy according to the invention over time and a graph showing the variation of the gate-source voltage with frequency;

[0043] Figure 8 is a graph showing the variation of the gate-source voltage, drain-source voltage and drain-source current of a power module with a shielding structure made of electrical steel according to the invention over time and a graph showing the variation of the gate-source voltage with frequency;

[0044] Figure 9 is a block diagram of an embodiment of a power converter according to the invention; and

[0045] Figure 10 It is a schematic diagram of an electric vehicle having an embodiment of an electric drive according to the present invention. Detailed Description

[0046] Figure 1 It is a partial top view of a first embodiment of the power module 1.

[0047] The power module 1 includes a first arrangement 2 of a plurality (exemplarily eight here) of dies 2a to 2h, each die 2a to 2h forming a transistor having a switching path. Each die 2a - 2h has a first terminal 3 (see Figure 3 ), a second terminal 4, and a control terminal 5. The switching path is formed between the first terminal 3 and the second terminal 4 and can be switched according to the voltage between the control terminal 5 and the second terminal 4. In this embodiment, the transistor is exemplarily implemented as a SiC MOSFET having a maximum blocking voltage of 1200V. Thus, the first terminal 3 is the drain terminal, the second terminal 4 is the source terminal, and the control terminal is the gate terminal. Furthermore, Figure 1 an optional Kelvin terminal 6 is depicted in

[0048] The transistors are connected in parallel by connecting the first terminals 3 to each other and the second terminals 4 to each other. In the Figure 1 exemplary configuration depicted in

[0049] Figure 2 and Figure 3 show the first arrangement 2, where Figure 2 is a top view and Figure 3 is a cross-sectional view.

[0050] The first arrangement 2 further includes a plate-shaped shielding structure 13 that completely covers the chips 2a to 2h. The shielding structure 13 is composed of nickel-zinc-based ferrite, nickel-iron soft ferromagnetic alloy, or electrical steel, or a combination of two or three of these materials. In the case of nickel-zinc-based ferrite, the maximum value of the imaginary part of its complex magnetic permeability is between 10 MHz and 1 GHz, and at a frequency of 100 MHz, preferably 50 MHz, more preferably 10 MHz, the real part of the complex magnetic permeability is reduced by 2 times or even 10 times compared to its value for a frequency close to zero.

[0051] In this embodiment, the power module 1 further includes a carrier 14, and the device 2 further includes a support structure 15. The carrier 14 is made of ceramic, in which a direct-bonded copper substrate (DBC) or an active metal brazed substrate (AMB) structure is formed, where the pads 8, 9, and the traces 11 are made of copper, or a direct-bonded aluminum substrate (DBA) is formed, where the pads 8, 9, and the traces 11 are made of aluminum. The chips 2a to 2h are arranged between the carrier 14 and the shielding structure 13. The support structure 15 is electrically insulating and mounts the shielding structure 13 at a predetermined distance from the chips 2a to 2h. In addition, the support structure 15 is a frame on which the shielding structure is arranged. Moreover, the power module 1 includes a single body 16 formed of an electrically insulating molding material. The body 16 covers the chips 2a to 2h, the electrical connections 7a to 7d, the pads 8, 9, 12, and the traces 11. The body 16 also embeds the shielding structure 13 and the support structure 15.

[0052] Referring again to Figure 1 , the power module 1 includes a second arrangement 2' corresponding to the first arrangement 2. The first terminal 3 of the first arrangement 2 is connected to the second terminal 4 of the second arrangement 2' through another electrical connection 7e to form a half-bridge.

[0053] Figure 4 is a detailed top view of the first arrangement 2 according to the second embodiment of the power module 1. The second embodiment corresponds to the first embodiment, and the differences between them are described below. The same or equivalent components are denoted by the same reference numerals.

[0054] Compared with the first embodiment, the trace 11 extends between the first pad 8 and the second pad 9, and the shielding structure 13 only covers the chips 2a, 2b, 2c, 2e, 2f, 2g. That is, the shielding structure 13 does not cover the chips 2d, 2h having the minimum distance from the first pad 8.

[0055] In this embodiment, the shielding structure 13 can be smaller than the shielding structure in the first embodiment because the feedback loop formed between the first terminal 3 of the dies 2d, 2h and the first pad 8 is significantly smaller than the corresponding feedback loops between the first terminals 3 and the first pads 8 of the other dies 2a, 2b, 2c, 2e, 2f, 2g. On the other hand, the dies 2d, 2h can be left uncovered because the feedback loop formed between the trace 11 and the first pad 8 is significantly smaller than the corresponding feedback loops via the other dies 2a, 2b, 2c, 2e, 2f, 2g. Note that, on the one hand, the influence of the feedback loop between the first terminal 3 and the first pad 8 and the influence of the feedback loop on the trace 11 and the third pad 12 should be evaluated in detail in order to decide which of the dies 2a to 2h is not covered by the shielding structure 13. According to another embodiment, the carrier 14 is made of metal having a dielectric coating (not shown) thereon, wherein an insulated metal substrate (IMS) is implemented.

[0056] According to another embodiment, the carrier is omitted and the body 16 covers or embeds the dies 2a to 2h, the electrical connections 7a to 7d, the pads 8, 9, 12 and the trace 11, wherein a transfer molded lead frame (TML) design is formed.

[0057] According to another embodiment, the support structure 15 is a plurality of domes, each dome selectively supporting the shielding structure 13. In addition, the support structure 15 can be electrically connected to the shielding structure 13.

[0058] Figures 5 to 8 Each shows a spectral decomposition diagram of the gate-source voltage UGS, the drain-source voltage UDS, and the drain-source current IDS varying with time t and the gate-source voltage UGS varying with frequency f. Note that in each right figure, the gate-source voltage UGS is normalized by the factor x. All signals have been measured at the external pads or auxiliary terminals of the power module 1, respectively.

[0059] Figure 5 Refers to a power module without a shielding structure corresponding to the power module 1 involved in the first embodiment. It can be seen that due to the inductive feedback loop formed by combining the non-linear voltage-dependent capacitances of the transistors by connecting the dies 2a to 2h in parallel, the switching signal that turns off the power module causes a significant oscillation of the gate-source voltage. It can be observed that the oscillation has a peak at 198 MHz, and the normalized amplitude a = 1.

[0060] Figure 6 Refers to a power module corresponding to the power module 1 involved in the first embodiment, in which the shielding structure is made of MnZn ferrite. This shielding structure even amplifies the oscillation to a normalized amplitude a = 2.26, and the peak is slightly shifted to 196 MHz. This negative effect is due to the fact that the real part of the complex permeability of this ferrite has a relatively high value μ′ at the peak.r and has a maximum value μ″ of the imaginary part of the complex permeability at a very low frequency of about 2 MHz r . Accordingly, a NiZn-based ferrite is proposed as the material of the shielding structure 13 according to the embodiment, and the ferrite has, for example, μ′ r = 2..3 at the peak frequency and has a maximum value μ″ at 70..100 MHz which is substantially closer to the peak frequency r .

[0061] Figure 7 Relates to a first embodiment, in which the shielding structure 13 is made of a NiFe soft ferromagnetic alloy (such as permalloy or high permeability alloy). It can be seen that although such an alloy is not generally considered to have significant high-frequency characteristics in the VHF range, the oscillation is attenuated to a normalized amplitude A = 0.47 and the peak is shifted to 200 MHz.

[0062] Figure 8 Relates to a first embodiment, in which the shielding structure 13 is made of electrical steel. The electrical steel is M330-35 in accordance with EN 10106:2015. It can be seen that although such electrical steel is not generally considered to have obvious high-frequency characteristics in the VHF range, the oscillation is attenuated to a normalized amplitude A = 0.14 and the peak is shifted to 208 MHz.

[0063] Figure 9 is a block diagram of an embodiment of the power converter 100.

[0064] The power converter 100 forms an inverter and includes a DC port 101 having two lines 102a, 102b for DC voltage, an AC port 103 having a plurality of phase conductors 104u, 104v, 104w for AC voltage, and a power supply section 105.

[0065] The power supply section 105 includes a plurality of switching elements. The switching elements are interconnected to half-bridges 106u, 106v, 106w for each of the phase conductors 104u, 104v, 104w. Each of the half-bridges 106u, 106v, 106w is formed by a power module 1 according to any of the above embodiments, such that each switching element is formed by one of the arrangements 2, 2'. In addition, each of the half-bridges 106u, 106v, 106 is connected to the DC 101, and each of the phase conductors 106u, 106v, 106 is connected to a center tap 107u, 107v, 107w between the switching elements of one of the half-bridges 106u, 106v, 106. Among them, the connection between the switching elements is realized by an electrical connector 7e (see Figure 1 ).

[0066] Figure 10Schematic diagram of an electric vehicle 110 of an embodiment having an electric drive 111.

[0067] The electric drive 111 includes an electric machine 112 configured to propel the vehicle 110 and a power converter 100 according to the above embodiment. The electric machine 112 is connected to an AC port 103 for supplying power to the electric machine 112. In addition, a DC port 101 is connected to a high-voltage battery 113 of the vehicle 110.

[0068] The electric vehicle 110 includes wheels 114 that are directly or indirectly coupled to the electric drive 111, for example via a transmission, so as to rotate the wheels 114. According to an embodiment, the electric vehicle 110 is a battery electric vehicle (BEV). Alternatively, the electric vehicle 110 may additionally include an internal combustion engine, thereby forming a hybrid vehicle. In addition, the electric vehicle 110 may include a fuel cell that powers the power converter 100.

Claims

1. A power module (1) comprising at least one arrangement (2, 2') of a plurality of dies (2a - h), each die forming a transistor having a switching path, each die (2a - h) having a first terminal (3), a second terminal (4) and a control terminal (5), the switching path being formed between the first terminal (3) and the second terminal (4) and being switchable in dependence on a voltage between the control terminal (5) and the second terminal (4), the transistors being connected in parallel by the first terminals (3) connected to each other and the second terminals (4) connected to each other, characterized in that, the at least one arrangement (2, 2') comprises a shielding structure (13), the shielding structure (13) at least partially covering at least two of the dies (2a - h), the shielding structure (13) comprising one material or a plurality of materials or consisting of one material or a plurality of materials selected from the group consisting of nickel - zinc - based ferrites, nickel - iron soft ferromagnetic alloys and electrical steel.

2. The power module according to claim 1, wherein, the electrical connections (7a - d) between the dies (2a - h) form a resonant circuit and a feedback loop, the resonant circuit having one or more resonant frequencies of at least 100 MHz, the feedback loop forming an inductive coupling between the second terminals (4) on the one hand and the first terminals (3) and / or control terminals (5) on the other hand, the shielding structure (13) being configured to reduce the inductive coupling.

3. The power module according to claim 1 or 2, wherein, the nickel - zinc - based ferrite has a complex magnetic permeability with a real part and an imaginary part, wherein, - in a frequency range between 10 MHz and 1 GHz, there is a maximum value of the imaginary part and / or - at a frequency of 100 MHz, preferably 50 MHz, more preferably 10 MHz, the real part of the complex magnetic permeability is reduced compared to its value for a frequency close to zero.

4. The power module according to any one of the preceding claims, wherein, The shielding structure (13) is plate - shaped.

5. The power module according to any one of the preceding claims, the at least one arrangement (2, 2') further comprises a conductive pad (8), the second terminals (4) being connected to the conductive pad (8), and - A conductive second pad (9) to which the first terminal (3) is connected, wherein, the shielding structure (13) does not cover the die (2d) having the minimum distance to the first pad (8) and / or - a conductive trace (13), the control terminals (5) being connected to the conductive trace (13), wherein the shielding structure (13) does not cover the die (2a) having the minimum distance to the first pad (8) or another conductive pad (12) of the power module (1), the Kelvin terminals (6) of the dies (2a - h) being connected to another conductive pad (12).

6. The power module according to any one of claims 1 to 4, wherein, The shielding structure (13) at least partially covers each die (2a - h).

7. The power module according to any one of the preceding claims, wherein, The shielding structure (13) completely covers the at least two dies (2a - h).

8. The power module according to any one of the preceding claims further comprises a single body (16) formed of an electrically insulating molding material, the body (16) covering the dies (2a-h) and / or the electrical connections (7a-d) between the dies, and the body (16) being embedded in the shielding structure (13).

9. The power module according to any one of the preceding claims further comprises a carrier (14), on which the dies (2a-h) are mounted, and at least two of the dies (2a-h) are arranged between the carrier (14) and the shielding structure (13).

10. The power module according to any one of the preceding claims, wherein the at least one arrangement (2, 2') further comprises a support structure (15) for mounting the shielding structure (13).

11. The power module according to claims 9 and 10, wherein, the support structure (15) is mounted on the carrier (14).

12. The power module according to claim 10 or 11, wherein, the support structure (15) is - electrically insulating and / or - a frame on which the shielding structure (13) is arranged, or a plurality of domes, each dome selectively supporting the shielding structure (13).

13. The power module according to any one of the preceding claims, wherein, a first arrangement (2) and a second arrangement (2') are provided, and the first terminal (3) of the first arrangement (2) is connected to the second terminal (4) of the second arrangement (2') so as to form a half-bridge (106u, 106v, 106w).

14. A power converter (100) comprising: - a DC port (101) for a DC voltage; - an AC port (103) having a plurality of phase conductors (104u, 104v, 104w) for an AC voltage; and - a power section (105) including a plurality of switching elements interconnected to half-bridges (106u, 106v, 106w) for each phase conductor, each half-bridge (106u, 106v, 106w) being connected to the DC port (101), and each phase conductor (104u, 104v, 104w) being connected to a center tap (107u, 107v, 107w) between switching elements of one of the half-bridges (106u, 106v, 106w); wherein each switching element or each half-bridge (106u, 106v, 106w) is formed by a power module (1) according to any one of the preceding claims.

15. An electric drive (111) for a vehicle, such as for a vehicle (110) or for a bicycle, comprising an electric motor (112) configured to propel the vehicle (110) and a power converter (100) according to claim 14, the electric motor (112) being connected to the AC port (103) of the power converter (100) for supplying an AC voltage to the electric motor (112).

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