Patent Application
20220201890
The present application is related and has right of priority to German Patent Application No. 10 2020 216 477.0 filed on Dec. 22, 2020, the entirety of which is incorporated by reference for all purposes.
The invention relates generally to a power module, in particular to a power module with an inner shielding member.
An inverter is usually used to convert direct current (‘DC’) to alternating current (‘AC’) to power a three-phase load, such as an electric motor. An inverter contains a power module 1 having power elements 12, such as insulated-gate bipolar transistors (IGBTs), metal-oxide-semiconductor field-effect transistors (MOSFETs) and Silicon Carbide (SiC) devices, and a drive board 2 driving these power elements 12, as shown in
To reduce the inductance of gate loops, the drive board 2 should be arranged closer to the power module 1. However, when the drive board 2 is closer to the power module 1, the power module 1 may interfere with the drive board 2 and cause malfunction of the power elements, namely an Electro Magnetic Compatibility (EMC) problem occurs.
Inserting an electrical shielding member 3 (such as a copper sheet) between the power module 1 and the drive board 2, as shown in
In order to balance the noise problem and the EMC problem, a power module with an inner shielding member is provided. The power module includes a case having an accommodation space and a baseplate with a circuit pattern provided on it, wherein the baseplate is jointed to the case such that the circuit pattern is accommodated in the accommodation space. The power module further includes a plurality of power elements provided on the circuit pattern and electrically connected to the circuit pattern, a grounded shielding member provided above the power elements and shielding the electromagnetic interference of the power elements, encapsulating material provided in the accommodation space, the encapsulating material covering at least the circuit pattern and the power elements, and a cover coupled to the case on a side of the case adjacent to the encapsulating material, where the cover and the baseplate enclose the accommodation space. Additionally, the power module includes a cooling member jointed to the baseplate on a side of the baseplate away from the case. By providing the shielding member inside the power module, electro-magnetic interference of the power elements is shielded effectively.
In a preferred embodiment, a portion of the accommodation space between the baseplate and the shielding member is filled with the encapsulating material. Typically, the encapsulating material, which is a gel, protects the power elements and the circuit pattern from dust and is used as a shock absorption layer.
In another preferred embodiment, a portion of the accommodation space between the shielding member and the cover is filled with the encapsulating material.
In another preferred embodiment, the case further has a supporting member for supporting the shielding member.
In another preferred embodiment, the supporting member is a flange provided on the inner sidewall of the case. The flange is preferably formed integrally with the case.
In another preferred embodiment, the shielding member is grounded to a ground of the cooling member by a conductive fastener or a wire via a metal layer in the case.
In another preferred embodiment, the power module further has a plurality of external connectors electrically connected to the circuit pattern, a plurality of through holes are respectively provided through the shielding member and the cover for the external connectors to pass through, the external connectors are electrically isolated from the shielding member.
In another preferred embodiment, the shielding member is a copper sheet or an aluminum sheet.
In another preferred embodiment, the circuit pattern is integrated into a DBC or an IMS provided on the baseplate.
According to another aspect of the invention, a power module is disclosed. The power module includes a case having an accommodation space and a baseplate with a circuit pattern provided on it, where the baseplate is jointed or coupled to the case such that the circuit pattern is accommodated in the accommodation space. The power module further includes a plurality of power elements provided on the circuit pattern and electrically connected to the circuit pattern, a grounded shielding member provided above the power elements to shield electromagnetic interference of the power elements, and an encapsulating material provided in the accommodation space, the encapsulating material covering at least the circuit pattern and the power elements. Additionally, the power module includes a cooling member jointed or coupled to the baseplate on a side of the baseplate away or further from the case, where the shielding member is coupled to the case on a side of the case adjacent to the encapsulating material, and where the shielding member and the baseplate enclose the accommodation space. In this design, the shielding member is used as a cover to make the power module as compact as possible.
In another preferred embodiment, the surface of the shielding member away or further from the baseplate is insulated to prevent a short circuit when a drive board is provided on the power module.
In another preferred embodiment, a patterned insulated layer is provided on the surface of the shielding member away or further from the baseplate. When the power module and a drive board are assembled, the patterned insulated layer corresponds to an area on the rear surface of the drive board where electronic elements are provided. The drive board is provided as close as possible to the power module since electronic elements are insulated to the power module due to the patterned insulated layer, thus the inductance of the gate loop is substantially decreased.
In another preferred embodiment, the accommodation space is filled with the encapsulating material. Typically, the encapsulating material, which is a gel, protects the power elements and the circuit pattern from dust and is used as a shock absorption layer.
In another preferred embodiment, the case further has a supporting member for supporting the shielding member.
In another preferred embodiment, the supporting member is a flange provided on the inner sidewall of the case. The flange is preferably formed integrally with the case.
In another preferred embodiment, the shielding member is grounded to a ground of the cooling member by a conductive fastener or a wire via a metal layer in the case.
In another preferred embodiment, the power module further has a plurality of external connectors electrically connected to the circuit pattern, a plurality of through holes are provided on the shielding member for the external connectors to pass through, the external connectors are electrically isolated from the shielding member.
In another preferred embodiment, the circuit pattern is integrated into a DBC or an IMS provided on the baseplate.
Other aspects and advantages of the embodiments will become apparent from the following detailed description taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the described embodiments.
The described embodiments and the advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawings. These drawings in no way limit any changes in form and detail that may be made to the described embodiments by on skilled in the art without departing from the spirit and scope of the described embodiments.
Reference will now be made to embodiments of the invention, one or more examples of which are shown in the drawings. Each embodiment is provided by way of explanation of the invention, and not as a limitation of the invention. For example, features illustrated or described as part of one embodiment can be combined with another embodiment to yield still another embodiment. It is intended that the present invention include these and other modifications and variations to the embodiments described herein.
Referring now to the drawings, embodiments of the invention are described in detail. A power module with an inner shielding member according to a first embodiment is described in detail with reference to
The case 1 has a frame structure defining the accommodation space 10, wherein one side of the case 1 is jointed to the baseplate 2, the other side of the case 1 is coupled with the cover 7, thus the accommodation space 10 is enclosed. The baseplate 2 becomes the bottom plate of the power module, supporting electronic components including the power elements 4. Metals having excellent thermal conductivity, for example, aluminum and aluminum alloy, or copper and copper alloy, may be used for the baseplate 2. The cooling member 20 with a Pin-Fin structure is jointed to the baseplate 2. In one embodiment, the cooling member 20 is made of the same material as the baseplate 2.
In the embodiment shown in
The power module further has a grounded shielding member 5 (
In order to place the shielding member 5, the case 1 is provided with a supporting member, such as a flange 11 provided on the inner sidewall of the case 1. The flange 11 is preferably formed integrally with the case 1 and the upper surface of the flange 11 is covered by a metal layer segment 81. As shown in
In the embodiment that the pins and the terminals are provided on the DBC, a plurality of through holes are respectively provided through or defined in the shielding member 5 and the cover 7 for the pins and the terminals to pass through, and the pins and the terminals are electrically isolated from the shielding member 5.
By providing encapsulating material (not shown), such as gel, into a portion of the accommodation space 10 between the baseplate 2 and the shielding member 5, the power elements 4 and the circuit pattern 33 are protected from dust and vibrations. Preferably, the accommodation space is fully filled with encapsulating material.
Now refer to
In another preferred embodiment, as shown in
In this inner shielding member design, the drive board is placed as close to the power module as possible, and the inductance of gate loop is reduced significantly. Thus, the noise caused by the inductance of gate loop is negligible. Meanwhile, with the help of the shielding member 5 inside the power module, the EMC problem is well contained even if the drive board is very close to the power module, or even contacts the power module. Hence, the contradiction between the noise problem and the EMC problem is compromised.
A number of alternative structural elements and processing steps have been suggested for the preferred embodiment. Thus, while the invention has been described with reference to specific embodiments, the description is illustrative of the invention and is not to be construed as limiting the invention. Various modifications and applications may occur to those skilled in the art without departing from the true spirit and scope of the invention as defined by the appended claims.
Modifications and variations can be made to the embodiments illustrated or described herein without departing from the scope and spirit of the invention as set forth in the appended claims. In the claims, reference characters corresponding to elements recited in the detailed description and the drawings may be recited. Such reference characters are enclosed within parentheses and are provided as an aid for reference to example embodiments described in the detailed description and the drawings. Such reference characters are provided for convenience only and have no effect on the scope of the claims. In particular, such reference characters are not intended to limit the claims to the particular example embodiments described in the detailed description and the drawings.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2020 216 477.0 | Dec 2020 | DE | national |
