Direct current support capacitor

Abstract

The utility model provides a direct current support capacitor, which comprises a capacitor metal shell, two capacitor core groups are arranged in the capacitor metal shell, each capacitor core group comprises a plurality of capacitor cores arranged in an array, and the surface of the capacitor metal shell is provided with conductive electrodes connected with the capacitor core groups. The conductive electrodes comprise a capacitor positive electrode, a capacitor middle electrode and a capacitor negative electrode which are sequentially distributed from the outer side to the inner side, and the conductive electrodes of the two capacitor core groups are symmetrically arranged; the surface of the capacitor core group is also provided with positive and negative copper plates, and the positive and negative copper plates comprise a positive upper composite copper plate located on the front surface, a negative upper composite copper plate located on the back surface, and a middle heat dissipation copper plate located on the side surface. According to the utility model, batch manufacturing in actual production can be met, the requirements of low inductance, high-frequency large current resistance and low heat dissipation of a double-level capacitor in a double-source circuit are met, and the service life and the reliability of the direct-current support capacitor under the operation condition are improved.

Description

Technical Field

[0001] The utility model relates to the technical field of capacitors, in particular to a direct current support capacitor. Background Art

[0002] Power electronic capacitors are increasingly advanced in the level of mechanical and electrical manufacturing industries, and the technological level of various electronic equipment is getting higher and higher. In particular, with the continuous maturity of silicon carbide IGBT applications, the energy density of various electronic equipment is getting higher and higher, and the requirements for the working environment temperature are getting higher and higher. As an indispensable and important part of electronic equipment, power electronic capacitors are increasingly required to work at higher and higher frequencies and larger currents as the energy density of electronic equipment increases. The working environment temperature of capacitors is getting higher and higher. Therefore, the requirements for current carrying and heat dissipation inside power electronic capacitors are becoming more and more stringent.

[0003] In order to increase the temperature rise of the hottest point inside the power electronic capacitor and reduce the influence of the high-frequency current skin effect on the heating of the capacitor, it is necessary to require that the current distribution inside the capacitor is as uniform as possible, the inductance is as low as possible, and the temperature rise of the hottest point is reduced.

[0004] At present, power electronic capacitors work in a high-current and high-frequency environment. Due to the different inductances of the copper bars connected at different positions inside the capacitor, the current distribution at various positions of the capacitor core is very uneven, resulting in excessive temperature rise at the position where the current is concentrated inside the capacitor core, which can easily reduce the working life of the capacitor. In severe cases, it may cause the capacitor to breakdown and other faults. Utility Model Content

[0005] In view of the above problems, the utility model provides a DC support capacitor. The application of dual-source technology in rail transit converters involved in this patent requires the realization of two groups of dual-level capacitors inside the capacitor to realize that the capacitor provides support for two groups of circuits at the same time. At the same time, the traditional positive-positive-middle-middle-negative-negative external circuit is modified to a positive-middle-negative-negative-middle-positive structure to reduce the inductance of the capacitor. The solution given in this patent is a solution to realize low-inductance, high-current-carrying-capacity dual-level DC support capacitors; this solution can meet the actual production of batch manufacturing, realize the dual-source circuit for dual-level capacitors with low inductance, high-frequency and large current resistance, and low heat dissipation, and improve the service life and reliability of the DC support capacitor under this operating condition.

[0006] In order to solve the above problems, the technical solution adopted by the utility model is:

[0007] A DC support capacitor comprises a capacitor metal shell, two groups of capacitor core groups are installed in the capacitor metal shell, the capacitor core group comprises a plurality of capacitor cores arranged in an array, a conductive electrode connected to the capacitor core group is arranged on the surface of the capacitor metal shell, the conductive electrode comprises a capacitor positive electrode, a capacitor middle electrode and a capacitor negative electrode which are sequentially distributed from the outside to the inside, and the conductive electrodes of the two groups of the capacitor core groups are symmetrically arranged; positive and negative copper plates are also arranged on the surface of the capacitor core group, the positive and negative copper plates comprise a positive electrode upper composite copper plate located on the front, a negative electrode upper composite copper plate located on the back and an intermediate electrode heat dissipation copper plate located on the side, wherein the positive electrode upper composite copper plate is connected to the capacitor positive electrode, the negative electrode upper composite copper plate is connected to the capacitor negative electrode, and the intermediate electrode heat dissipation copper plate is connected to the capacitor intermediate electrode.

[0008] Preferably, the intermediate pole heat dissipation copper plate and the intermediate pole of the capacitor are connected via an intermediate pole composite copper plate.

[0009] Preferably, the outer side of the intermediate-pole composite copper plate is installed with an intermediate-pole internal core connection copper plate and an intermediate-pole parallel connection copper plate, and the intermediate-pole internal core connection copper plate and the intermediate-pole parallel connection copper plate form a composite structure.

[0010] Preferably, the surfaces of the positive electrode upper composite copper plate and the negative electrode upper composite copper plate are provided with a plurality of core and copper plate welding pad locations, and the plurality of core and copper plate welding pad locations are arranged in an array and are located directly above the capacitor core.

[0011] Preferably, the core and the copper plate welding pad are in a bent S shape.

[0012] Preferably, the surfaces of the positive electrode upper composite copper plate and the negative electrode upper composite copper plate are also arranged with a plurality of copper plate heat dissipation connection holes, and the plurality of copper plate heat dissipation connection holes and the core and copper plate welding pads are arranged alternately.

[0013] The beneficial effects of the utility model are:

[0014] The dual-circuit supporting function of the capacitor is realized in the dual-source technology, avoiding the uneven distribution of dual-circuit current caused by the inductance deviation of the traditional capacitor connection method during bidirectional support, affecting the normal operation of the circuit, and meeting the inductance balance requirements of the dual-source technology for dual-level capacitors; this solution realizes the requirements of low inductance, high-frequency and large current resistance, and low heat dissipation for dual-level capacitors in the dual-source circuit, thereby improving the service life and reliability of the DC support capacitor under this operating condition. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a finished capacitor according to an embodiment of the utility model.

[0016] Figure 2This is a schematic diagram of the first angle structure of the internal capacitor of the utility model.

[0017] Figure 3 This is a schematic diagram of the second angle structure of the capacitor of the utility model.

[0018] Figure 4 For this utility model Figure 3 Schematic diagram of the enlarged area structure.

[0019] Figure 5 It is a schematic diagram of the intermediate-stage lead-out structure of the utility model.

[0020] In the figure: 1. Metal shell of capacitor; 2. Metal mounting bracket of capacitor; 3. Negative pole of capacitor; 4. Middle pole of capacitor; 5. Positive pole of capacitor; 6. Copper plate for heat dissipation of middle pole; 7. Copper plates for positive and negative poles; 8. Welding pads for core and copper plates; 9. Heat dissipation connection holes for copper plates; 10. Core of capacitor; 11. Composite copper plate on the upper part of positive pole; 12. Composite copper plate on the upper part of negative pole; 13. Composite copper plate on middle pole; 14. Copper plate for connecting the core inside middle pole; 15. Copper plates for parallel connection of middle poles. DETAILED DESCRIPTION

[0021] The utility model is further described below in conjunction with the accompanying drawings and embodiments.

[0022] Power electronic capacitors are increasingly advanced in the level of mechanical and electrical manufacturing industries, and the technological level of various electronic equipment is getting higher and higher. In particular, with the continuous maturity of silicon carbide IGBT applications, the energy density of various electronic equipment is getting higher and higher, and the requirements for the working environment temperature are getting higher and higher. As an indispensable and important part of electronic equipment, power electronic capacitors are increasingly required to work at higher and higher frequencies and larger currents as the energy density of electronic equipment increases. The working environment temperature of capacitors is getting higher and higher. Therefore, the requirements for current carrying and heat dissipation inside power electronic capacitors are becoming more and more stringent.

[0023] In order to increase the temperature rise of the hottest point inside the power electronic capacitor and reduce the influence of the high-frequency current skin effect on the heating of the capacitor, it is necessary to require that the current distribution inside the capacitor is as uniform as possible, the inductance is as low as possible, and the temperature rise of the hottest point is reduced.

[0024] At present, power electronic capacitors work in a high-current and high-frequency environment. Due to the different inductances of the copper bars connected at different positions inside the capacitor, the current distribution at various positions of the capacitor core is very uneven, resulting in excessive temperature rise at the position where the current is concentrated inside the capacitor core, which can easily reduce the working life of the capacitor. In severe cases, it may cause the capacitor to breakdown and other faults.

[0025] Please refer to the attached Figure 1-5 , a DC support capacitor, the finished capacitor is as follows Figure 1As shown, it includes a capacitor metal shell 1, a capacitor metal mounting bracket 2 is installed on the outside of the capacitor metal shell 1, and array-arranged capacitor cores 10 are installed in the capacitor metal shell 1. The capacitor metal shell 1 is filled with a high-heat dissipation resin to fix multiple capacitor cores 10, so as to achieve efficient heat dissipation and ensure the stability of the internal structure.

[0026] Please refer to the attached Figure 3 The interface on the outside of the DC support capacitor is modified to a positive-center-negative-negative-center-positive structure based on the traditional positive-positive-center-negative external circuit, that is, it is arranged in sequence as a capacitor positive pole 5, a capacitor middle pole 4, a capacitor negative pole 3, a capacitor negative pole 3, a capacitor middle pole 4, and a capacitor positive pole 5; through the above arrangement, the two capacitor positive poles 5 can be distributed at the two outermost positions, which can effectively reduce the capacitor inductance and reduce the temperature rise of the capacitor.

[0027] A strip-shaped intermediate pole heat dissipation copper plate 6 is installed at the outer edge of multiple capacitor cores 10. The intermediate pole heat dissipation copper plate 6 can limit the capacitor core 10 from the outside and further dissipate the heat emitted by the capacitor core 10. The intermediate pole heat dissipation copper plate 6 here is connected to the intermediate pole 4 of the capacitor. The heat on the surface of the intermediate pole 4 of the capacitor can be efficiently dissipated through the intermediate pole heat dissipation copper plates 6 on both sides, thereby achieving efficient and accurate heat dissipation.

[0028] In order to further reduce the temperature rise of the battery and improve the heat dissipation effect of multiple capacitors, positive and negative copper plates 7 are installed on the surface of the capacitor core 10, which can further improve the heat dissipation effect of the capacitor.

[0029] Specifically; the positive and negative copper plates 7 include a positive electrode upper composite copper plate 11 installed on the first side surface of the capacitor, and a negative electrode upper composite copper plate 12 installed on the second side surface of the capacitor, and an intermediate electrode composite copper plate 13 installed in the middle position, the positive electrode upper composite copper plate 11 is connected to the positive electrode 5 of the capacitor, the negative electrode upper composite copper plate 12 is connected to the negative electrode 3 of the capacitor, and the intermediate electrode composite copper plate 13 is connected to the intermediate electrode 4 of the capacitor, which meets the current dispersion and cooling requirements; realizes effective heat dissipation of the heat inside the core, avoids the accumulation effect of heat causing the capacitor to heat up, and reduces the reliability of the capacitor.

[0030] It should also be noted that copper bars are used throughout the capacitors to reduce the inductance of the capacitors and improve the heat dissipation of the capacitors.

[0031] The intermediate pole composite copper plate 13 realizes composite connection on the upper part of the capacitor and the negative pole upper composite copper plate 12 and the positive pole upper composite copper plate 11 to effectively reduce the capacitor inductance; the intermediate pole internal core connection copper plate 14 and the intermediate pole parallel connection copper plate 15 are installed on the outside of the composite connection, and the intermediate pole internal core connection copper plate 14, the intermediate pole parallel connection copper plate 15 and the end area of ​​the copper plate form a composite structure as a whole, which can further ensure the stability of the composite area, and further effectively reduce the capacitor inductance, realize effective heat dissipation, and improve the overall stability and reliability of the capacitor.

[0032] Furthermore, according to the different positions of the core connected to the copper busbar, the core and copper plate welding pad portion 8 is set to balance the overall inductance of the capacitor copper busbar and the core and copper plate welding pad portion 8 to ensure that the current passing through the capacitor cores at different positions is the same.

[0033] The cross-section of the core and the copper plate welding pad 8 here is S-shaped, which increases the connection area and can achieve effective connection with the capacitor core 10. While ensuring the connection stability between the copper plate and the capacitor core 10, it can increase the heat dissipation area and further ensure the operation of the capacitor in a large capacitance and high frequency environment.

[0034] The core and copper plate welding pad part 8 located away from the capacitor negative pole 3, the capacitor middle pole 4, and the capacitor positive pole 5 are designed to be symmetrically designed with a hook shape, which can also ensure that the current passing through the capacitor core at different positions is the same. Similarly, the above-mentioned structural design can greatly reduce the design cost while meeting the current carrying condition.

[0035] In order to improve the current carrying capacity of the capacitor, the capacitor core 10 adopts a double-row parallel connection method to reduce the internal resistance of the core and reduce the heat generation of the core. Four core groups are arranged inside and connected into two groups of double core groups with the same structure through copper plates. The overall structure is compactly arranged internally without wasting space, meeting the requirements of small-volume installation.

[0036] A plurality of copper plate heat dissipation connection holes 9 are arranged on the surface of the positive electrode upper composite copper plate 11 and the negative electrode upper composite copper plate 12. The plurality of copper plate heat dissipation connection holes 9 and the core and copper plate welding pad parts 8 are arranged in a staggered manner, which can effectively dissipate heat. The copper plate heat dissipation connection holes 9 here are located between the four core and copper plate welding pad parts 8, which ensures structural strength while achieving efficient heat dissipation.

[0037] In summary, this solution can meet the needs of mass production in actual production, realize the requirements of low inductance, high-frequency and high-current resistance, and low heat dissipation for dual-level capacitors in dual-source circuits, and improve the service life and reliability of the DC support capacitors under this operating condition.

[0038] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention shall be included in the protection scope of the present invention.

Claims

1. A DC support capacitor, comprising a capacitor metal shell (1), two groups of capacitor core groups are installed in the capacitor metal shell (1), the capacitor core group comprises a plurality of capacitor cores (10) arranged in an array, and a conductive electrode connected to the capacitor core group is provided on the surface of the capacitor metal shell (1), characterized in that: The conductive electrodes include a capacitor positive electrode (5), a capacitor middle electrode (4) and a capacitor negative electrode (3) which are sequentially distributed from the outside to the inside, and the conductive electrodes of the two groups of capacitor core groups are symmetrically arranged; the surface of the capacitor core group is also provided with positive and negative copper plates (7), and the positive and negative copper plates (7) include a positive electrode upper composite copper plate (11) located on the front, a negative electrode upper composite copper plate (12) located on the back, and an intermediate electrode heat dissipation copper plate (6) located on the side; wherein the positive electrode upper composite copper plate (11) is connected to the capacitor positive electrode (5), the negative electrode upper composite copper plate (12) is connected to the capacitor negative electrode (3), and the intermediate electrode heat dissipation copper plate (6) is connected to the capacitor intermediate electrode (4).

2. A DC support capacitor according to claim 1, characterized in that: The intermediate pole heat dissipation copper plate (6) and the capacitor intermediate pole (4) are connected via an intermediate pole composite copper plate (13).

3. A DC support capacitor according to claim 2, characterized in that: The outer side of the intermediate pole composite copper plate (13) is provided with an intermediate pole internal core connection copper plate (14) and an intermediate pole parallel connection copper plate (15), and the intermediate pole internal core connection copper plate (14) and the intermediate pole parallel connection copper plate (15) form a composite structure.

4. A DC support capacitor according to claim 1, characterized in that: The surfaces of the positive electrode upper composite copper plate (11) and the negative electrode upper composite copper plate (12) are provided with a plurality of core and copper plate welding pad portions (8), and the plurality of core and copper plate welding pad portions (8) are arranged in an array and are located directly above the capacitor core (10).

5. A DC support capacitor according to claim 4, characterized in that: The core and the copper plate welding pad portion (8) is bent in an S-shape.

6. A DC support capacitor according to claim 4, characterized in that: The surfaces of the positive electrode upper composite copper plate (11) and the negative electrode upper composite copper plate (12) are also provided with a plurality of copper plate heat dissipation connection holes (9), and the plurality of copper plate heat dissipation connection holes (9) and the core and copper plate welding pad portions (8) are arranged in a staggered manner.

Images