Power electronic system
By setting damping materials on the conductor surface of the power electronic system to form a high impedance path, the problem of difficult EMI noise in the prior art is solved, and a high-efficiency and low-noise power electronic system design is achieved.
Patent Information
- Application Number
- CN202411871523.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-12-19
- Filing Date
- 2024-12-18
- Publication Date
- 2025-06-20
AI Technical Summary
The EMI noise generated by existing power electronic systems in high-speed switching and packaging and PCB wiring is difficult to effectively suppress, resulting in component and system failures and may not comply with electromagnetic compatibility specifications.
Using a conductor with a damping function, a high impedance path is formed to reduce high-frequency EMI noise by providing a damping material on the surface of the conductor. The damping material has different resistance values at different frequencies and has a relative permeability greater than 1 at frequencies above 1 MHz.
It effectively reduces high-frequency EMI noise in power electronic systems, improves the efficiency, power density and reliability of the system, and ensures that the system complies with electromagnetic compatibility specifications.
Smart Images
Figure CN120185374A_ABST
Abstract
Description
Technical Field
[0001] This case relates to a power electronic system, and particularly to a power electronic system including a conductor with damping function. Background Art
[0002] In the applications of transportation electrification and smart grid, the demand for power electronic systems with large capacity and high power density is increasing day by day. With the development of SiC devices, power electronic systems are sufficient to achieve high efficiency and high power density. However, high-speed switching and parasitic parameters in packaging and PCB (printed circuit board) wiring will inevitably generate more EMI (electromagnetic interference) noise. These high-frequency EMI noises may cause component and system failures. Moreover, EMI noises may also make the power electronic system fail to meet the electromagnetic compatibility specifications.
[0003] Generally, large-sized EMI filters are often used to reduce EMI. In addition, before adding an EMI filter, measures need to be taken to reduce or suppress EMI noises at the circuit board or packaging level to ensure that the noises will not affect the normal operation of the system.
[0004] Therefore, how to develop a power electronic system that can improve the above-mentioned existing technologies is an urgent need at present. Summary of the Invention
[0005] The purpose of this case is to provide a power electronic system including a conductor with damping function. In the power electronic system of this case, high-frequency components will flow through a high-impedance path and be reduced due to power loss.
[0006] To achieve the above purpose, this case provides a power electronic system including a plurality of power devices and conductors. The conductors are configured to connect the plurality of power devices, and a damping portion is included on the surface of the conductor. The damping portion is at least partially formed by a damping material. The damping material has different resistance values at different frequencies, and the relative permeability of the damping material at frequencies higher than 1 MHz is greater than 1. The damping portion forms a first path and a second path. The first path and the second path are respectively for a first power current and a second power current flowing between the plurality of power devices to pass through. The first power current is at a frequency higher than 1 MHz, and the second power current is at a frequency lower than 1 MHz. The impedance of the first path is greater than the impedance of the second path.
[0007] To achieve the above object, the present case further provides a power electronic system, including a plurality of power devices and conductors. The conductors are configured to connect the plurality of power devices, and a damping portion is included on the surface of the conductors. The damping portion has an average roughness greater than 20 μm and / or a maximum height roughness greater than 50 μm. Description of the Drawings
[0008] Figure 1A Illustrates the current distribution in the conductor at low frequencies.
[0009] Figure 1B Illustrates the current distribution in the conductor at high frequencies.
[0010] Figure 2 Schematic cross-sectional view of the conductor of the first embodiment of the present case.
[0011] Figure 3 Schematic cross-sectional view of the conductor of the second embodiment of the present case.
[0012] Figure 4 Schematic cross-sectional view of the conductor of the third embodiment of the present case.
[0013] Figure 5 Schematic cross-sectional view of the conductor of the fourth embodiment of the present case.
[0014] Figure 6 Schematic cross-sectional view of the conductor of the fifth embodiment of the present case.
[0015] Figure 7A Schematic cross-sectional view of the conductor of the sixth embodiment of the present case.
[0016] Figure 7B Illustrates Figure 7A the current distribution of each part of the conductor at different frequencies.
[0017] Figure 8A , Figure 8B and Figure 8C Schematic three-dimensional structure views of conductors with different surface appearances.
[0018] Figure 9 Illustrates Figure 8A , Figure 8B and Figure 8C the curves of the resistance values of the conductors in
[0019] Figure 10 Illustrates the circuit topology using the conductor proposed in the present case.
[0020] Figure 11 Illustrates the packaged device using the conductor proposed in the present case.
[0021] Figure 12Illustrate a power module package using the conductor proposed in this case.
[0022] Among them, the reference numerals are explained as follows:
[0023] 1: Conductor
[0024] I: Current
[0025] δ: Skin depth
[0026] 1a, 1b, 1c, 1d: Conductor
[0027] 11a, 11b, 11c, 11d: Damping part
[0028] 12: First layer
[0029] 13: Second layer
[0030] 10: Main body part
[0031] 1e, 1f: Conductor
[0032] 11e, 11f: Damping part
[0033] 14: Insulation layer
[0034] 10a, 10b: Main body part
[0035] D1: Current direction
[0036] D2: Observation line
[0037] A1, A2, A3, A4: Region
[0038] 2a, 2b, 2c: Conductor
[0039] 20: Main body part
[0040] 21: Rough layer
[0041] 22: Damping material
[0042] R2a, R2b, R2c: Resistance value
[0043] 31: Switching element
[0044] 32: Conductor
[0045] 33: Pin
[0046] 34: Bonding wire
[0047] 35, 36: Lead frame terminal Detailed implementation method
[0048] Some exemplary embodiments embodying the features and advantages of the present case will be described in detail in the following description. It should be understood that the present case can have various variations in different embodiments, all of which do not depart from the scope of the present case, and the descriptions and illustrations therein are for illustrative purposes in nature and not for limiting the present case.
[0049] In the present case, a damping technique is proposed, which can be used to reduce high-frequency EMI noise in power electronic systems. This damping technique helps to reduce the high-frequency EMI noise generated during the switching of power devices, the operation of power electronic systems, and the parallel connection of components. The proposed damping technique is an easy-to-implement and low-cost technique that utilizes the natural characteristics of conductors to suppress high-frequency noise in power electronic systems. Thereby, the proposed damping technique and the power electronic systems to which it applies can achieve high efficiency, high power density, and good reliability.
[0050] Please refer to Figure 1A and Figure 1B . Figure 1A illustrates the current distribution in a conductor at low frequencies, Figure 1B illustrates the current distribution in a conductor at high frequencies. In Figure 1A and Figure 1B , current I flows through conductor 1, and the current distribution is shown through the relationship between the current density and the internal depth of conductor 1. When current I is at low frequencies (e.g., below 1 MHz), as shown in Figure 1A , the current densities at different depths in conductor 1 are similar, meaning that current I is uniformly distributed in conductor 1. When current I is at high frequencies (e.g., above 1 MHz), as shown in Figure 1B , the current density at the surface of conductor 1 is higher, while the current density at the central part of conductor 1 is lower. In other words, under high-frequency conditions, affected by the skin effect and proximity effect, current I naturally concentrates on the surface of conductor 1. In addition, the eddy currents generated thereby are also shown in the figure.
[0051] Under high-frequency conditions, the skin depth δ can be obtained through Equation (1):
[0052]
[0053] In Equation (1), ω represents the angular frequency, σ represents the conductivity, and μ represents the permeability. The existence of the skin effect and proximity effect means that high-frequency currents will choose different paths to flow compared to low-frequency currents.
[0054] Since the current I naturally concentrates on the surface of the conductor 1 at high frequencies, a conductor with a damping function at least on the surface is proposed in this case to increase the high-frequency impedance and suppress high-frequency noise. The proposed conductor can be structured on the power devices in the power electronic system, thereby improving the efficiency, power density, and reliability of the power electronic system. For ease of understanding, several embodiments of the conductor are illustrated below.
[0055] Please refer to Figure 2 , Figure 2 which is a cross-sectional schematic diagram of the conductor of the first embodiment of this case. In Figure 2 , the current distribution of the current I at high frequencies is shown. As Figure 2 shown, the conductor 1a includes a damping portion 11a formed of a damping material, wherein the damping material has different resistance values at different frequencies, and the relative permeability of the damping material is greater than 1 at frequencies higher than 1 MHz. Based on the characteristics of the damping material, the damping portion 11a forms two paths for the first power current and the second power current (i.e., the first current and the second current related to power transmission) flowing through the conductor 1a between the power devices. The first power current is at high frequency (e.g., higher than 1 MHz), the second power current is at low frequency (e.g., lower than 1 MHz), and the impedance of the first path is higher than that of the second path. In some embodiments, the damping material has low conductivity and high permeability, and can be, for example but not limited to, nickel, iron, and aluminum. In some embodiments, the permeability of the damping material is higher than that of copper, and the conductivity of the damping material is lower than that of copper.
[0056] In addition, in this embodiment, the conductor 1a is entirely composed of the damping material, but this case is not limited thereto. For example, in another embodiment, the damping material may also only form a part of the conductor.
[0057] Please refer to Figure 3 , Figure 3 which is a cross-sectional schematic diagram of the conductor of the second embodiment of this case. As Figure 3 shown, in this embodiment, the conductor 1b includes a damping portion 11b on its surface, and the damping portion 11b has an average roughness (Ra) greater than 20 μm and / or a maximum height roughness (Rz) greater than 50 μm. In one embodiment, the average roughness of the damping portion 11b is greater than 20 μm. In another embodiment, the maximum height roughness of the damping portion 11b is greater than 50 μm. In yet another embodiment of this case, the average roughness (Ra) of the damping portion 11b is greater than 20 μm and its maximum height roughness (Rz) is greater than 50 μm. From the above several embodiments, the damping portion 11b forms a rough surface of the conductor 1b and provides high impedance. Therefore, when the current I is at high frequency, the current I naturally concentrates on the surface of the conductor 1b and flows through the rough surface with high impedance, thereby reducing high-frequency noise.
[0058] Please refer to Figure 4 , Figure 4 which is a cross-sectional view of the conductor of the third embodiment of this case. As Figure 4 shown, the conductor 1c includes a damping portion 11c, where the damping portion 11c is disposed on the surface of the conductor 1c and is formed of the aforementioned damping material. When the current I is at high frequency, the current I naturally concentrates on the surface of the conductor 1c and flows through the damping portion 11c with high impedance, thereby reducing high-frequency noise.
[0059] Please refer to Figure 5 , Figure 5 which is a cross-sectional view of the conductor of the fourth embodiment of this case. The conductor 1d combines the characteristics of the conductors 1b and 1c. Specifically, as Figure 5 shown, the conductor 1d includes a damping portion 11d, and the damping portion 11d includes a first layer 12 and a second layer 13. Similar to Figure 3 the damping portion 11b in, the first layer 12 has an average roughness greater than 20 μm and / or a maximum height roughness greater than 50 μm. In one embodiment, the first layer 12 has an average roughness greater than 20 μm to provide high impedance. In another embodiment. The first layer 12 has a maximum height roughness greater than 50 μm, which can also provide the effect of high impedance. In addition, in yet another embodiment, the first layer 12 simultaneously has an average roughness greater than 20 μm and a maximum height roughness greater than 50 μm to provide high impedance. The second layer 13 is disposed on the first layer 12 and is formed of the aforementioned damping material. It should be noted that in this embodiment, the first layer 12 is covered by the second layer 13. However, in another embodiment, the second layer 13 can also be configured to only fill the recessed portions of the first layer 12 without completely covering the first layer 12.
[0060] It should be noted that the shape of the conductor is not limited, and the damping portion can be disposed on part or the entire surface of the conductor. For example, the conductor can be cylindrical (such as a wire), rectangular, or any suitable shape. Furthermore, when the conductor has two opposite surfaces, the conductor can include two damping portions respectively disposed on the two opposite surfaces (such as Figure 3 , Figure 4 and Figure 5 shown), or can include only one damping portion disposed on one of the surfaces. Moreover, if the conductor includes two damping portions respectively disposed on two opposite surfaces, and each damping portion is at least partially formed of the damping material, the damping materials forming the two damping portions can be different, but both meet the aforementioned definition of the damping material.
[0061] In addition, in Figure 3 , Figure 4 and Figure 5In the illustrated embodiment, each of the conductors 1b, 1c, and 1d further includes a body portion 10, and the damping portions 11b, 11c, and 11d are all disposed on the surface of the body portion 10. The body portion 10 can be made of, for example but not limited to, copper, which is a material widely used in existing conductors. Taking Figure 4 the conductor 1c in [reference] as an example, the method for determining the size of the conductor is illustrated as follows. The relationship between the size of the conductor 1c and the thickness, conductivity, and resistance value of the body portion 10 is shown in Equation (2).
[0062]
[0063] In Equation (2), t m represents the thickness of the body portion 10, l0 represents the actual length of the conductor 1c, σ m represents the conductivity of the body portion 10, d represents the effective width of the body portion 10, and R m represents the resistance value of the body portion 10. From the foregoing description, it can be seen that the body portion 10 forms the main path for transmitting low-frequency current. Therefore, when a specific resistance value needs to be achieved at low frequencies, the thickness t of the body portion 10 can be calculated through Equation (2). m .
[0064] In addition, an equation related to the resistance value of the layer formed of the damping material (such as the damping portion 11c) is illustrated as follows:
[0065]
[0066] In Equation (3), R s represents the resistance value of the damping portion 11c, τ r represents the surface roughness coefficient, ω represents the angular frequency, μ r represents the relative permeability of the damping material, μ i represents the initial permeability, and σ s represents the conductivity of the damping material. Since the angular frequency ω and the resistance value R s will be specifically determined to suppress high-frequency noise, the actual length l0 and the effective width d (i.e., the size) of the conductor 1c can be calculated through Equation (3). Additionally, according to Equation (3), increasing the surface roughness will increase the surface roughness coefficient τ r , and thereby increase the resistance value R s . Therefore, in Figure 5 the illustrated conductor 1d, the rough surface formed by the first layer 12 of the damping portion 11d can further increase the resistance value of the damping portion 11d.
[0067] In addition, in this case, the conductor can adopt a multi-layer structure. Please refer to Figure 6 , Figure 6Schematic cross-sectional view of the conductor according to the fifth embodiment of the present case. As Figure 6 shown, the conductor 1c includes a plurality of main parts 10 and a plurality of damping parts 11e, and each damping part 11e is formed of the damping material defined above. Two opposite surfaces of each main part 10 are respectively covered by two damping parts 11e. Furthermore, in the conductor 1c, any two adjacent main parts 10 are isolated by an insulating layer 14, and the insulating layer 14 is formed of an insulating material. It should be noted that the actual materials used to form the plurality of damping parts 11e may be the same or different, but all comply with the definition of the damping material in the present case.
[0068] Please refer to Figure 7A and Figure 7B . Figure 7A Schematic cross-sectional view of the conductor according to the sixth embodiment of the present case. As Figure 7A shown, the conductor 1f includes two main parts 10a and 10b, an insulating layer 14, and a damping part 11f. The insulating layer 14 is located between the main parts 10a and 10b and is used to isolate the two. The damping part 11f is provided on the main part 10a. In Figure 7A , the current direction D1 and the observation line D2 are shown. Along the observation line D2, A1, A2, A3, and A4 respectively represent the regions of the main part 10b, the insulating layer 14, the main part 10a, and the damping part 11f. Figure 7B Illustrates Figure 7A the current distributions of the respective parts of the conductor at different frequencies. In Figure 7B , the current distributions at frequencies of 100 kHz, 100 MHz, and 1 GHz are respectively represented by solid lines, dashed lines, and dotted chain lines. As Figure 7A and Figure 7B shown, at a frequency of 100 kHz, the current mainly flows through the main part 10a; at a frequency of 100 MHz, the current mainly flows through the damping part 11f; at a frequency of 1 GHz, the current mainly flows through the damping part 11f and the main part 10b.
[0069] Figure 8A , Figure 8B and Figure 8C Schematic three-dimensional structure views of conductors having different surface appearances. In Figure 8A , the conductor 2a includes a main part 20 with a smooth surface. In Figure 8BIn [description], conductor 2b includes a main body portion 20 and a rough layer 21 (in a spiral shape). The rough layer 21 is disposed on the main body portion 20 and has an average roughness greater than 20 μm and / or a maximum height roughness greater than 50 μm. In one embodiment, the rough layer 21 is disposed on the main body portion 20 and has an average roughness greater than 20 μm. In another embodiment, the rough layer 21 is disposed on the main body portion 20 and has a maximum height roughness greater than 50 μm. In yet another embodiment, the rough layer 21 is disposed on the main body portion 20 and has an average roughness greater than 20 μm and a maximum height roughness greater than 50 μm. In Figure 8C [description], conductor 2c includes a main body portion 20, a rough layer 21, and a damping material 22, where the rough layer 21 is similar to that shown in Figure 8B [description]. The damping material 22 conforms to the aforementioned definition of the damping material and is filled in the recessed portions of the rough layer 21.
[0070] Figure 9 illustrates Figure 8A , Figure 8B and Figure 8C the curves of the resistance values of the conductors in [description] varying with frequency. In Figure 9 [description], R2a, R2b, and R2c respectively represent the resistance values of conductors 2a, 2b, and 2c in Figure 8A , Figure 8B and Figure 8C [description]. As shown in Figure 9 , when the frequency is lower than 1 MHz, the resistance values R2a and R2b are nearly the same, and the resistance value R2c is greater than the resistance values R2a and R2b. When the frequency is higher than 1 MHz, the resistance value R2b gradually increases and is greater than the resistance value R2a. When the frequency is 100 MHz, the resistance value R2c is much greater than the resistance values R2a and R2b. Thus, it can be seen that the damping material can significantly increase the resistance value at high frequencies, thereby effectively reducing high-frequency noise.
[0071] In this case, the proposed conductor structure is for connecting power devices in a power electronics system. It should be noted that the specific implementation manners of the power electronics system and its power devices are not limited. In other words, the conductors in this case can be used to suppress high-frequency noise in various power electronics systems. For example, the conductors in this case can be configured as the traces of a printed circuit board, the pins of a packaged device, the traces in a power module package, clamping members, or lead frame terminals, etc., but are not limited thereto. The following illustrates several application cases.
[0072] Figure 10 illustrates a circuit topology using the conductors proposed in this case. As shown in Figure 10As shown, the switching element 31 is connected by a conductor 32, and the conductor 32 can adopt the conductor proposed in this case to suppress high-frequency noise. For example, the switching element 31 can be a power device on a printed circuit board, and the conductor 32 can be a circuit on a printed circuit board.
[0073] Figure 11 An encapsulated device using the conductor proposed in this case is illustrated. As Figure 11 shown, the pins 33 of the device package can adopt the conductor proposed in this case to suppress high-frequency noise.
[0074] Figure 12 A power module package using the conductor proposed in this case is illustrated. As Figure 12 shown, the bonding wires 34 and lead frame terminals 35 and 36 in the power module package can adopt the conductor proposed in this case to suppress high-frequency noise. In addition, in Figure 12 the power module package shown, the circuits and clamping parts on the substrate can also adopt the conductor proposed in this case.
[0075] It should be noted that the above are only preferred embodiments proposed for the purpose of illustrating this case. This case is not limited to the described embodiments, and the scope of this case is determined by the claims. And this case can be variously modified by those skilled in the art, but all are not beyond what the claims are intended to protect.
Claims
1. A power electronic system comprising: a plurality of power devices; and a conductor, configured to connect the plurality of power devices, and comprising a damping portion on a surface of the conductor, wherein the damping portion is at least partially formed of a damping material, the damping material has different resistance values at different frequencies, and the relative magnetic permeability of the damping material at a frequency higher than 1 MHz is greater than 1, in, The damping part forms a first path and a second path, and the first path and the second path are respectively used for a first power current and a second power current flowing between the multiple power devices to pass through, the first power current is at a frequency higher than 1 MHz, and the second power current is at a frequency lower than 1 MHz, and the impedance of the first path is greater than the impedance of the second path.
2. The power electronic system as claimed in claim 1, wherein the damping portion comprises a first layer and a second layer, the first layer having an average roughness greater than 20 μm and / or a maximum height roughness greater than 50 μm, and the second layer is disposed on the first layer and is formed by the damping material. The power electronic system as claimed in claim 2 , wherein the first layer is covered by the second layer. The power electronic system as claimed in claim 2 , wherein the second layer is structured to fill a recessed portion of the first layer. 5 . The power electronic system as claimed in claim 2 , wherein the conductor comprises two damping portions, and the two damping portions are respectively disposed on two opposite surfaces of the conductor. 6 . The power electronic system as claimed in claim 5 , wherein the damping material comprises a first material and a second material that are different, and the two second layers of the two damping parts are respectively formed by the first material and the second material. 7 . The power electronic system as claimed in claim 1 , wherein the conductor comprises two damping portions, and the two damping portions are respectively disposed on two opposite surfaces of the conductor. 8 . The power electronic system as claimed in claim 7 , wherein the damping material comprises a first material and a second material that are different from each other, and the two damping parts are respectively formed by the first material and the second material.
9. The power electronic system as claimed in claim 1, wherein the conductor comprises a plurality of main body parts, two opposite surfaces of each main body part are respectively covered by two damping parts, and any two adjacent main body parts are separated by an insulating layer.
10. The power electronic system of claim 1, wherein the damping material comprises nickel, iron and aluminum.
11. The power electronic system of claim 1, wherein the conductor is configured as a trace of a printed circuit board, a pin of a packaged device, or a trace, a clip, or a lead frame terminal in a power module package.
12. A power electronic system comprising: a plurality of power devices; and A conductor is constructed to connect the plurality of power devices and comprises a damping portion on the surface of the conductor, wherein the damping portion has an average roughness greater than 20 μm and / or a maximum height roughness greater than 50 μm. 13 . The power electronic system as claimed in claim 12 , wherein the conductor comprises two damping portions, and the two damping portions are respectively disposed on two opposite surfaces of the conductor.