Busbar structure and EMC filter
By integrating dielectrics between busbars to form capacitors within the busbar structure, the size constraints of traditional EMC filters are overcome, enhancing design flexibility in power conversion devices.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- TOYOTA JIDOSHA KK
- Filing Date
- 2024-12-11
- Publication Date
- 2026-06-23
AI Technical Summary
Existing EMC filters for power conversion devices are large in size, limiting the flexibility in enclosure and mounting design due to the need for separate X capacitors connected between flat bus bars.
Configuring the busbar structure itself to function as a capacitor by inserting dielectrics between pairs or multiple busbars, allowing the busbar structure to act as an X capacitor, thereby eliminating the need for separate capacitors.
This configuration enables a more compact EMC filter design, increasing the flexibility in housing and mounting options for power conversion devices.
Smart Images
Figure 2026102327000001_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to a bus bar structure and an EMC filter.
Background Art
[0002] A bus bar is a conductor that conducts a large amount of current. The bus bar is used, for example, in a power conversion device. In a power conversion device having a bus bar, electromagnetic noise generated inside and outside the power conversion device may be conducted through the bus bar. In this case, there has been a problem that the conducted electromagnetic noise causes malfunction of the power conversion device or surrounding electronic devices.
[0003] To solve this problem, Patent Document 1 discloses a technique of a power conversion device that suppresses electromagnetic noise by having a high-voltage noise filter. This high-voltage noise filter is an EMC (Electromagnetic Compatibility) filter formed by attaching a magnetic core, an X capacitor, and a Y capacitor to a bus bar.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Summary of the Invention
Problems to be Solved by the Invention
[0005] However, since the above-described EMC filter connects an X capacitor between two flat bus bars arranged side by side, its size is large. That is, in the above-described technique, there has been a problem that the degree of freedom in housing design or mounting design is reduced because it is necessary to incorporate an EMC filter having a large size.
[0006] This disclosure aims to solve the aforementioned problems by providing a busbar structure and an EMC filter utilizing the busbar structure, which increase the degree of freedom in enclosure design or mounting design by configuring the busbar itself to function as a capacitor. [Means for solving the problem]
[0007] Aspects of the present disclosure preferably include a busbar structure that transmits a DC power supply and comprises a plurality of busbars installed opposite each other, and a dielectric inserted between a specific pair of busbars included in the plurality of busbars, wherein the pair of busbars and the dielectric form a capacitor. [Effects of the Invention]
[0008] According to the embodiments of this disclosure, by configuring the busbar itself to function as an X capacitor, the degree of freedom in enclosure design or mounting design can be increased. [Brief explanation of the drawing]
[0009] [Figure 1] This is a cross-sectional view showing an example of the configuration of an EMC filter according to Embodiment 1 of this disclosure. [Figure 2] This is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 2 of this disclosure. [Figure 3] This is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 3 of this disclosure. [Figure 4] This is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 4 of the present disclosure. [Figure 5] This is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 5 of the present disclosure. [Modes for carrying out the invention]
[0010] The busbar structure and other components related to this disclosure will be described with reference to the drawings. The same or corresponding components will be denoted by the same reference numeral, and repetition of the description may be omitted. In addition, all structures shown in the cross-sectional views related to this disclosure will have equal lengths in the depth direction of the page.
[0011] Embodiment 1 Figure 1 is a cross-sectional view showing an example configuration of an EMC filter according to Embodiment 1 of this disclosure. The EMC filter according to this embodiment is applied to a power converter.
[0012] The EMC filter 10 consists of a magnetic core 11 and a busbar structure 20 provided inside it. The busbar structure 20 consists of a pair of busbars 21 and 22 and a dielectric 25 inserted between them. The pair of busbars 21 and 22 are busbars for transmitting DC power in a power conversion device. One of the pair of busbars 21 and 22 is the N-line busbar 21, and the other is the P-line busbar 22.
[0013] The P-line busbar 22 is installed opposite the N-line busbar 21. Preferably, the P-line busbar 22 is parallel to the N-line busbar 21. The busbar structure 20, which consists of the N-line busbar 21, the P-line busbar 22, and the dielectric 25, functions as the X-capacitor of the power converter.
[0014] The advantages of the busbar structure according to this embodiment will be explained in more detail. The EMC filter in the power converter disclosed in Patent Document 1 has an X capacitor to suppress differential noise. This X capacitor is connected between two flat busbars placed side by side. As a result, the size of the EMC filter becomes large. Furthermore, power converters that need to incorporate a large EMC filter have reduced flexibility in the enclosure design or mounting design.
[0015] On the one hand, the bus bar structure 20 according to this embodiment is configured to function as an X capacitor by inserting a dielectric between a plurality of bus bars for transmitting a DC power supply. As a result, since there is no need to mount an X capacitor separately from the bus bar, the EMC filter can be miniaturized. That is, the bus bar structure 20 according to this embodiment can increase the degree of freedom in housing design or mounting design.
[0016] Embodiment 2 FIG. 2 is a cross-sectional view showing a configuration example of a bus bar structure according to Embodiment 2 of the present disclosure. The bus bar structure 20a according to this embodiment is different from Embodiment 1 in that the number of poles of the bus bar is more than two. Therefore, the bus bar structure 20a according to this embodiment has a plurality of pairs of bus bars that function as capacitors.
[0017] The bus bar structure 20a has an N-line bus bar 21 and a P-line bus bar 22. A common bus bar 23 is arranged between the N-line bus bar 21 and the P-line bus bar 22. The common bus bar 23 is a bus bar for transmitting a DC power supply. Also, the common bus bar 23 is preferably parallel to the N-line bus bar 21 and the P-line bus bar 22.
[0018] A dielectric 25a is inserted between the N-line bus bar 21 and the common bus bar 23. The dielectric 25a is a dielectric showing a first relative permittivity. The N-line bus bar 21, the common bus bar 23, and the dielectric 25a form a first capacitor.
[0019] Also, a dielectric 25b is inserted between the common bus bar 23 and the P-line bus bar 22. The dielectric 25b is a dielectric showing a second relative permittivity. The common bus bar 23, the P-line bus bar 22, and the dielectric 25b form a second capacitor.
[0020] Furthermore, a dielectric 25c is inserted between the N-line bus bar 21 and the P-line bus bar 22. The dielectric 25c is a dielectric showing a third relative permittivity. The N-line bus bar 21, the P-line bus bar 22, and the dielectric 25c form a third capacitor.
[0021] Here, the bus bar structure 20a functions as an X capacitor of the power conversion device. Therefore, the first, second, and third capacitors are designed such that each has the same capacitance.
[0022] Further, this embodiment shows a mode in which the capacitor areas of the first, second, and third capacitors are the same. That is, the lengths of the first, second, and third capacitors in the left - right direction of the drawing are all equal to L1.
[0023] Unlike Embodiment 3 to be described later, in this embodiment, the N - line bus bar 21 and the P - line bus bar 22 are not bent. Therefore, the electrode - to - electrode distances related to the first capacitor and the second capacitor are at least different in magnitude from the electrode - to - electrode distance related to the third capacitor.
[0024] That is, in order for the capacitances of the first, second, and third capacitors to be the same, at least the relative dielectric constants of the dielectrics 25a and 25b and the dielectric 25c need to be different. On the other hand, when the electrode - to - electrode distances of the first capacitor and the second capacitor are the same in magnitude, the relative dielectric constants of the dielectric 25a and the dielectric 25b need to be equal.
[0025] As described above, the bus bar structure 20a according to this embodiment can increase the degree of freedom in housing design or mounting design even when the number of poles of the bus bar is more than two.
[0026] Embodiment 3 FIG. 3 is a cross - sectional view showing a configuration example of a bus bar structure according to Embodiment 3 of the present disclosure. The bus bar structure 20b according to this embodiment is different from Embodiment 2 in that the N - line bus bar 21a and the P - line bus bar 22a are bent.
[0027] The bus bar structure 20b has a bent N - line bus bar 21a and a bent P - line bus bar 22a. The N - line bus bar 21a and the P - line bus bar 22a are arranged opposite to each other. It is preferable that a part of the P - line bus bar 22a is parallel to a part of the N - line bus bar 21a.
[0028] Furthermore, a common busbar 23 is positioned between the N-line busbar 21a and the P-line busbar 22a. Preferably, the common busbar 23 is parallel to a portion of the N-line busbar 21a and a portion of the P-line busbar 22a.
[0029] A dielectric 25a is inserted between the N-line busbar 21a and the common busbar 23. The N-line busbar 21a, the common busbar 23, and the dielectric 25a form a first capacitor.
[0030] Furthermore, it is preferable that the dielectric 25a is inserted between the region where the N-line busbar 21 and the common busbar 23 are parallel to each other. By making the N-line busbar 21 and the common busbar 23 parallel to each other, the electric field formed can be distributed uniformly, thereby increasing the energy conservation capability of the capacitor. The same applies to the capacitors described later.
[0031] Furthermore, a dielectric 25b is inserted between the common busbar 23 and the P-line busbar 22a. The common busbar 23, the P-line busbar 22a, and the dielectric 25b form a second capacitor.
[0032] Furthermore, a dielectric 25d is inserted between the N-line busbar 21a and the P-line busbar 22a. Dielectric 25d is a dielectric exhibiting a fourth relative permittivity. The N-line busbar 21, the P-line busbar 22, and the dielectric 25d form a fourth capacitor.
[0033] Here, the busbar structure 20b functions as the X capacitor of the power converter. Therefore, the first, second, and fourth capacitors are designed to have the same capacitance.
[0034] Furthermore, this embodiment shows a configuration in which the capacitor areas of the first, second, and fourth capacitors are the same. That is, the lengths of the first, second, and fourth capacitors in the left-right direction on the plane of the paper are all equal, L1. Therefore, for example, if the distance between the electrodes of the first, second, and fourth capacitors is the same, the relative permittivity of the dielectrics 25a, 25b, and 25d must be the same.
[0035] As described above, the busbar structure 20b according to this embodiment can increase the degree of freedom in enclosure design or mounting design even when there are more than two busbars.
[0036] Embodiment 4 Figure 4 is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 4 of this disclosure. The busbar structure 20c according to this embodiment differs from Embodiment 3 in that at least one of the capacitor areas of the first, second, and fifth capacitors (described later) is different from the others.
[0037] The busbar structure 20c has a bent N-line busbar 21b and a bent P-line busbar 22b. The N-line busbar 21b and the P-line busbar 22b are installed opposite each other. Preferably, a portion of the P-line busbar 22b is parallel to a portion of the N-line busbar 21b.
[0038] Furthermore, a common busbar 23 is positioned between the N-line busbar 21b and the P-line busbar 22b. Preferably, the common busbar 23 is parallel to a portion of the N-line busbar 21b and a portion of the P-line busbar 22b.
[0039] A dielectric 25a is inserted between the N-line busbar 21b and the common busbar 23. The N-line busbar 21b, the common busbar 23, and the dielectric 25a form a first capacitor.
[0040] Furthermore, a dielectric 25b is inserted between the common busbar 23 and the P-line busbar 22b. The common busbar 23, the P-line busbar 22b, and the dielectric 25b form a second capacitor.
[0041] Furthermore, a dielectric 25e is inserted between the N-line busbar 21b and the P-line busbar 22b. Dielectric 25e is a dielectric exhibiting a fifth relative permittivity. The N-line busbar 21b, the P-line busbar 22b, and the dielectric 25e form a fifth capacitor.
[0042] Here, the busbar structure 20c functions as the X capacitor of the power converter. Therefore, the first, second, and fifth capacitors are designed to have the same capacitance.
[0043] Furthermore, this embodiment shows a configuration in which at least one of the capacitor areas of the first, second, and fifth capacitors differs from the others. Here, the configuration shows that the length of the first and second capacitors in the left-right direction of the paper is L1, and the length of the fifth capacitor in the left-right direction of the paper is L2. That is, in order for the capacitances of the first, second, and fifth capacitors to be the same, the relative permittivity of at least the dielectrics 25a and 25b and the dielectric 25e must be different.
[0044] As described above, the busbar structure 20c according to this embodiment can increase the degree of freedom in enclosure design or mounting design, even when at least one of the capacitor areas of the multiple sets of capacitors is different from the others.
[0045] Embodiment 5 Figure 5 is a cross-sectional view showing an example of the configuration of a busbar structure according to Embodiment 5 of this disclosure. The busbar structure 20d according to this embodiment differs from Embodiment 4 in that the N-line busbar 21c and P-line busbar 22c, which will be described later, are bent only once.
[0046] The busbar structure 20d has a bent N-line busbar 21c and a bent P-line busbar 22c. The N-line busbar 21c and the P-line busbar 22c are installed opposite each other. Preferably, a portion of the P-line busbar 22c is parallel to a portion of the N-line busbar 21c.
[0047] Furthermore, a common busbar 23 is positioned between the N-line busbar 21c and the P-line busbar 22c. Preferably, the common busbar 23 is parallel to a portion of the N-line busbar 21c and a portion of the P-line busbar 22c.
[0048] A dielectric 25a is inserted between the N-line busbar 21c and the common busbar 23. The N-line busbar 21c, the common busbar 23, and the dielectric 25a form a first capacitor.
[0049] Furthermore, a dielectric 25b is inserted between the common busbar 23 and the P-line busbar 22c. The common busbar 23, the P-line busbar 22c, and the dielectric 25b form a second capacitor.
[0050] Furthermore, a dielectric 25f is inserted between the N-line busbar 21c and the P-line busbar 22c. Dielectric 25f is a dielectric exhibiting a sixth relative permittivity. The N-line busbar 21c, the P-line busbar 22c, and the dielectric 25f form a sixth capacitor.
[0051] Here, the busbar structure 20d functions as the X capacitor of the power converter. Therefore, the first, second, and sixth capacitors are designed to have the same capacitance.
[0052] Furthermore, this embodiment shows a configuration in which at least one of the capacitor areas of the first, second, and sixth capacitors differs from the others. Here, the configuration shows that the length of the first and second capacitors in the horizontal direction on the plane of the paper is L1, and the length of the sixth capacitor in the vertical direction on the plane of the paper is L3. That is, in order for the capacitances of the first, second, and sixth capacitors to be the same, the relative permittivity of at least the dielectrics 25a and 25b and the dielectric 25f must be different.
[0053] As described above, the busbar structure 20d according to this embodiment can increase the degree of freedom in enclosure design or mounting design, even when at least one of the capacitor areas of the multiple capacitors differs from the others.
[0054] While this disclosure describes an application of the busbar structure to a power converter, the applications are not limited to this. Today, regulations concerning electromagnetic noise are being strengthened in countries around the world. In particular, the electrical industry is required to strengthen EMC countermeasures in limited spaces. The busbar structure relating to this disclosure may be applied to such products in the electrical industry. Furthermore, the busbar structure relating to this disclosure may be applied to automobiles. Electromagnetic noise generated in automobiles increases with the degree of electrification of automobiles. Therefore, automobiles are also products that require strengthened EMC countermeasures in limited spaces. [Explanation of symbols]
[0055] 10 EMC filters 11 Magnetic core 20 Busbar Structures 20a Busbar structure 20b Busbar structure 20c Busbar Structure 20d Busbar Structure 21 Bus Bar 22 Bus Bar 25 Dielectrics 25a Dielectric 25b Dielectric 25c dielectric 25d dielectric 25e dielectric 25f dielectric
Claims
1. It transmits DC power to multiple busbars installed opposite each other, A dielectric is inserted between a specific pair of busbars included in the plurality of busbars, The pair of busbars and the dielectric form a capacitor. Busbar structure.
2. Having multiple sets of the aforementioned pair of busbars, Each of the aforementioned pairs of busbars forms a capacitor with the same capacitance. The busbar structure according to claim 1.
3. Having multiple sets of the aforementioned pair of busbars, Each of the aforementioned pairs of busbars forms a capacitor with an equal capacitor area. The busbar structure according to claim 1.
4. The pair of busbars are such that at least a portion of them is parallel to each other. The dielectric is inserted between the regions where the pair of busbars are parallel to each other. The busbar structure according to claim 1.
5. An EMC filter comprising a busbar structure according to any one of claims 1 to 4 inside a magnetic core.