Large-current square low-self-inductance direct-current support capacitor

Abstract

The utility model discloses a large-current square low-self-inductance direct current support capacitor, which comprises a shell, a capacitor core module and electrodes, the capacitor core module is packaged in the shell through potting materials, the capacitor core module comprises a plurality of flat film capacitor cores which are arranged in a rectangular array, and the electrodes are arranged on the flat film capacitor cores. The edge of the conductive thin film for winding the flat thin film capacitor is wave-shaped; the electrodes comprise an input electrode and an output electrode, each of the input electrode and the output electrode comprises a mother copper bar and a plurality of son copper bars, two ends of each group of longitudinal flat film capacitor cores of the capacitor core module are electrically connected with the son copper bars of the input electrode and the output electrode respectively, and the upper end of each son copper bar is electrically connected with the transversely arranged mother copper bar; a front row of leading-out terminals and a rear row of leading-out terminals are arranged outside the top of the shell, and the lower ends of the leading-out terminals are close to the inner side wall of the shell and extend into the shell to be electrically connected with the female copper bar. The direct current support capacitor has wide working frequency and low self-inductance, and can be used in cooperation with a SiC MOSFET (Metal-Oxide-Semiconductor Field Effect Transistor).

Description

TECHNICAL FIELD

[0001] The utility model relates to capacitor technical field, especially a big current square low self -inductance DC -link capacitor. BACKGROUND

[0002] Si MOSFET, Si IGBT and SiC MOSFET can be used for electric energy conversion, but its power level, driving method and working mode are different. In terms of switching frequency, the switching frequency of Si MOSFET is >20kHz, the switching frequency of Si IGBT is 5kHz~10kHz, and the switching frequency of SiC MOSFET is >50kHz. SiC MOSFET can switch at high frequency, and higher power density, higher efficiency and lower heat dissipation can be realized.

[0003] The role of DC-Link capacitor is to use the characteristics that capacitor voltage cannot be suddenly changed and capacitor capacity resistance decreases with the increase of frequency to provide a low impedance channel for the system in a wide frequency band, thereby reducing the AC impedance of the DC bus. With the increase of frequency, the impedance gradually decreases, and at f=f0 (resonant frequency), it has the lowest impedance, which is equivalent series resistance ESR; when f>f0 (resonant frequency), the capacitor no longer has capacity resistance, but presents inductance, at which the capacitor has lost its function. Therefore, the working frequency of the capacitor should be much lower than the resonant frequency.

[0004] SiC MOSFET needs a DC-Link capacitor with a wider working frequency (i.e. a very high resonant frequency point) to match its high working frequency, which reduces the self-inductance ESL (Equivalent Series Inductance) of the capacitor.

[0005] Therefore, a DC-Link capacitor with low self-inductance and wide working frequency is needed to match SiC MOSFET, to ensure that the capacitor does not overheat when passing high-frequency large current, and to ensure safe and reliable operation of the system. UTILITY MODEL CONTENTS

[0006] The utility model aims at providing a big current square low self -inductance DC -link capacitor with reasonable structure, wide working frequency, low self -inductance and can match SiC MOSFET.

[0007] The utility model is characterized in that:

[0008] The utility model discloses a high current square low self -inductance DC support capacitor, including casing, capacitor core module and electrode, and capacitor core module is encapsulated in the casing through the filling material, and the capacitor core module includes a plurality of flat film capacitor core that is arranged in rectangular array, and the edge of the conductive film for winding flat film capacitor is in the shape of a wave, and the electrode includes input electrode and output electrode, and the input electrode and output electrode all include female copper row and a plurality of sub copper row, and the both ends of each group longitudinal column flat film capacitor core of capacitor core module are electrically connected with the sub copper row of input electrode and output electrode respectively, and the upper end of each sub copper row is electrically connected with the female copper row that is arranged horizontally, and the top of casing is equipped with two rows of leading-out terminal from front to back, and the lower end of leading-out terminal is close to the inner side wall of casing and extends into the casing and is electrically connected with the female copper row.

[0009] The purpose of the utility model can also be solved by the following technical measures:

[0010] As a more specific scheme, the leading-out terminal is a 7-shaped plug, the upper end of which is supported on the top of the casing, and the lower end is integrated with the upper end of the female copper row.

[0011] As a further scheme, the end of the capacitor core is separated from the inner wall of the casing by a certain distance, the upper end of the sub copper row of the input electrode and the output electrode is provided with an outward turning edge, the outer end of the outward turning edge is electrically connected with the female copper row, or the sub copper row of the input electrode is in a U shape, the outer side upper end of which is electrically connected with the female copper row of the input electrode, the upper end of the sub copper row of the output electrode is provided with an outward turning edge, and the outer end of the outward turning edge is electrically connected with the female copper row of the output electrode.

[0012] As a further scheme, the casing includes a plastic shell and a plastic cover plate, the plastic shell is provided with a deep cavity, the top of the deep cavity is open, the capacitor core module is arranged in the deep cavity, the outer periphery bottom of the plastic cover plate is provided with a supporting step, and the plastic cover plate is supported on the top surface of the plastic shell through the step surface of the supporting step; the edge of the plastic cover plate is provided with a slot corresponding to the leading-out terminal, and the lower end of the leading-out terminal passes through the slot from the outside to the inside.

[0013] As a further scheme, the upper end of the leading-out terminal is provided with a threaded hole, the threaded hole is formed by a nut connected to the bottom of the upper end of the leading-out terminal, or the upper end of the leading-out terminal is provided with a downward extending flange hole, the inner wall of the flange hole is provided with a thread to form a threaded hole.

[0014] As a further scheme, the plastic cover plate is provided with a clearance opening corresponding to the nut or the flange hole.

[0015] As a further scheme, the top surface of the plastic cover plate is provided with a sunken platform corresponding to the upper end of the leading-out terminal, and the upper end of the leading-out terminal is embedded in the sunken platform.

[0016] As a further scheme, the plastic cover plate is provided with a pouring hole; and the lower end side wall of the plastic shell is provided with a connecting lug.

[0017] The utility model discloses the beneficial effects are as follows:

[0018] (1) the capacitor core film of this big current square low self-induction DC support capacitor adopts wavy slitting, and is flattened, and the design of the female copper bar and the son copper bar is integrated, reduces the path and can utilize the mutual offset of positive and negative magnetic field to reduce self-induction, and the plug-in piece is inlaid nut type, and the plug-in piece is close to the shell, to realize the low self-induction (ESL <14nH) of capacitor, has wider working frequency, to be suitable for the use of SiC MOSFET,

[0019] (2) the self-induction of this big current square low self-induction DC support capacitor can be less than 14nH, makes capacitor can safely and reliably run under high power, large current and high frequency.Capacitor design meets the requirement of future power electronics technology high frequency integration, reduces the stray inductance of capacitor, can effectively reduce capacitor heating, reduces the non-uniformity of capacitor internal current, ensures that capacitor does not overheat when passing through high frequency and large current, guarantees the safe and reliable operation of system. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 It is the exploded structure schematic view of an embodiment of the utility model.

[0021] Figure 2 It is the local structure schematic view of another angle of electrode in the utility model.

[0022] Figure 3 It is the local structure schematic view of another angle of electrode in the utility model.

[0023] Figure 4 It is the plastic cover plate structure schematic view in the utility model.

[0024] Figure 5 It is the overhead structure schematic view of the utility model.

[0025] Figure 6 It is the main view structure schematic view of the utility model.

[0026] Figure 7 It is the side view structure schematic view of the utility model.

[0027] Figure 8 It is Figure 6 A-A sectional structure schematic view of.

[0028] Figure 9 It is Figure 8 Enlarged structure schematic view of B in.

[0029] Figure 10 Equivalent circuit schematic diagram of the utility model.

[0030] Figure 11 Equivalent circuit schematic diagram of another embodiment of the utility model.

[0031] Figure 12 Figure 11 Input electrode structure schematic diagram of the equivalent circuit. DETAILED DESCRIPTION

[0032] The utility model will be further described in connection with the drawings and examples:

[0033] Referring to Figures 1-10 As shown in the figure, a large current square low self-inductance DC support capacitor, comprising a shell, a capacitor core module 2 and an electrode 3, the capacitor core module 2 is encapsulated in the shell through the potting material 5, the electrode 3 is electrically connected with the capacitor core module 2 and extends out of the shell, the capacitor core module 2 comprises a plurality of capacitor cores, and the plurality of capacitor cores are arranged in a rectangular array; the two ends of the plurality of capacitor cores are connected in parallel through input electrodes 3 and output electrodes 3 respectively, the input electrode C and the output electrode D both comprise a copper bar 31 and a plurality of sub-copper bars 33, the sub-copper bars 33 are electrically connected with the longitudinal column capacitor cores of the capacitor core module 2, and the upper ends of the sub-copper bars 33 are electrically connected with the horizontally arranged copper bar 31; the top of the shell is externally provided with front and rear rows of lead-out terminals 32, the lower ends of the lead-out terminals 32 are close to the inner side wall of the shell and extend into the shell and are electrically connected with the copper bar 31.

[0034] The capacitor core is a flat film capacitor, and the edge of the conductive film for winding the flat film capacitor is in a wave shape.

[0035] The lead-out terminal 32 is a 7-shaped plug, the upper end of which is supported on the top of the shell, and the lower end is integrally connected with the upper end of the copper bar 31.

[0036] The end of the capacitor core is separated from the inner wall of the shell by a certain distance; the upper end of the sub-copper bar 33 of the input electrode C and the output electrode D is provided with an outward turned edge 34, and the outer end of the outward turned edge 34 is electrically connected with the copper bar 31.

[0037] The shell comprises a plastic shell 1 and a plastic cover plate 4, the plastic shell 1 is provided with a deep cavity, the top of the deep cavity is open, the capacitor core module 2 is arranged in the deep cavity, the outer periphery of the plastic cover plate 4 is provided with a supporting step 41, and the plastic cover plate 4 is supported on the top surface of the plastic shell 1 through the step surface of the supporting step 41; the edge of the plastic cover plate 4 is provided with a slot 42 corresponding to the lead-out terminal 32, and the lower end of the lead-out terminal 32 passes through the slot 42 from outside to inside.

[0038] ​The upper end of the lead-out terminal 32 is provided with a threaded hole formed by a nut 35 connected to the bottom of the upper end of the lead-out terminal 32. The plastic cover plate 4 is provided with a clearance hole 43 corresponding to the nut 35, and the nut 35 extends into the shell 1 through the clearance hole 43.

[0039] The top surface of the plastic cover plate 4 is provided with a sunken platform corresponding to the upper end of the lead-out terminal 32, and the upper end of the lead-out terminal 32 is embedded in the sunken platform.

[0040] The plastic cover plate 4 is provided with a pouring hole 44, and the lower end side wall of the plastic shell 1 is provided with a connecting lug 11.

[0041] Combining Figure 11 And Figure 12 As shown in the drawings, the sub-copper row 33 of the input electrode C is in a U shape, and the outer side upper end thereof is electrically connected to the female copper row 31 of the input electrode C. The upper end of the sub-copper row 33 of the output electrode D is provided with an outward turning edge 34, and the outer end of the outward turning edge 34 is electrically connected to the female copper row 31 of the output electrode D.

[0042] The above is the preferred scheme of the utility model, which displays and describes the basic principle, main features and advantages of the utility model. Those skilled in the art should understand that the utility model is not limited by the above-mentioned embodiments, and the above-mentioned embodiments and the description in the specification are only to illustrate the principle of the utility model. Without departing from the spirit and scope of the utility model, the utility model can have various changes and improvements, and these changes and improvements all fall within the scope of the utility model to be protected. The scope of protection of the utility model is defined by the appended claims and their equivalents.

Claims

1. A high current square low self-inductance DC support capacitor comprising a casing, a capacitor core module (2) and electrodes (3), the capacitor core module (2) being encapsulated in the casing by a potting compound (5), characterized in that: The capacitor core module (2) comprises a plurality of flat film capacitor cores arranged in a rectangular array, the edges of the conductive film of the flat film capacitor core are arranged in a wave shape; the electrode (3) comprises an input electrode (C) and an output electrode (D), the input electrode (C) and the output electrode (D) each comprise a female copper bar (31) and a plurality of sub-copper bars (33), the two ends of each group of longitudinal column flat film capacitor cores of the capacitor core module (2) are electrically connected with the sub-copper bars (33) of the input electrode (C) and the output electrode (D) respectively, and the upper end of each sub-copper bar (33) is electrically connected with the horizontally arranged female copper bar (31); the top of the shell is externally provided with two rows of lead-out terminals (32) in front and back, the lower end of the lead-out terminal (32) is close to the inner side wall of the shell and extends into the shell to be electrically connected with the female copper bar (31).

2. The high current square low self-inductance DC blocking capacitor of claim 1, wherein: The lead-out terminal (32) is a 7-shaped plug, the upper end of which is supported on the top of the shell, and the lower end is integrally connected with the upper end of the female copper bar (31).

3. The high current square low self-inductance DC blocking capacitor of claim 1, wherein: The end of the capacitor core is separated from the inner wall of the shell by a certain distance; the upper end of the sub-copper bar (33) of the input electrode (C) and the output electrode (D) is provided with an outward turning edge (34), and the outer end of the outward turning edge (34) is electrically connected with the female copper bar (31); or the sub-copper bar (33) of the input electrode (C) is in a U shape, the outer side upper end of which is electrically connected with the female copper bar (31) of the input electrode (C), and the upper end of the sub-copper bar (33) of the output electrode (D) is provided with an outward turning edge (34), and the outer end of the outward turning edge (34) is electrically connected with the female copper bar (31) of the output electrode (D).

4. The high current square low self-inductance DC blocking capacitor of claim 2, wherein: The shell comprises a plastic shell (1) and a plastic cover plate (4), the plastic shell (1) is provided with a deep cavity, the top of the deep cavity is open, the capacitor core module (2) is arranged in the deep cavity, the outer periphery bottom of the plastic cover plate (4) is provided with a supporting step (41), and the plastic cover plate (4) is supported on the top surface of the plastic shell (1) through the step surface of the supporting step (41); the edge of the plastic cover plate (4) is provided with a slot (42) corresponding to the lead-out terminal (32), and the lower end of the lead-out terminal (32) passes through the slot (42) from outside to inside.

5. The high current square low self-inductance DC blocking capacitor of claim 4, wherein: The upper end of the lead-out terminal (32) is provided with a threaded hole formed by a nut (35) connected to the bottom of the upper end of the lead-out terminal (32), or the upper end of the lead-out terminal (32) is provided with a downwardly extending flange hole, and the inner wall of the flange hole is provided with a thread to form a threaded hole; The plastic cover plate (4) is provided with a clearance opening (43) corresponding to the nut (35) or the flange hole.

6. The high current square low self-inductance DC blocking capacitor of claim 4, wherein: The top surface of the plastic cover plate (4) is provided with a sunken platform corresponding to the upper end of the lead-out terminal (32), and the upper end of the lead-out terminal (32) is embedded in the sunken platform.

7. The high current square low self-inductance DC blocking capacitor of claim 4, wherein: The plastic cover plate (4) is provided with a pouring hole (44); and the lower end side wall of the plastic shell (1) is provided with a connecting lug (11).

Images