JP2008079479A - Power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power converter of which the inductance between a capacitor and an electronic circuit unit does not increase. <P>SOLUTION: The power converter comprises a capacitor 11 having a tubular terminal part 13 consisting of two terminals arranged coaxially and connected to a power supply, and a plurality of power devices 12, connected through the tubular terminal part 13, that are connected to a motor 16. The inductance between the capacitor 11 and the connection part between the tubular terminal part 13 and the power devices 12 is made constant. The capacitor 11 comprises the tubular terminal part 13, a dielectric member 19 which comprises a negative electrode and a positive electrode and is wound, a current lead 20 for connecting the tubular terminal part 13 form the negative electrode and the positive electrode, an insulating holder 28 which fixes the tubular terminal part 13, and a capacitor case 11a for fixing the insulating holder 28. A - side current lead and + side current lead are alternately arranged in spiral or circumferentially. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a power converter, and more particularly to a power converter for driving an electric drive for an automobile.

  Conventionally, a “semiconductor device” (see Patent Document 1), which is a power converter, is known. This “semiconductor device” includes a bus bar arranged on the circumference, and a plurality of electronic circuit units arranged at a plurality of locations in the circumferential direction on the bus bar and mounted with semiconductor elements. Inverter devices that supply current from the on-vehicle battery via the bus bar, and each electronic circuit unit is provided with an arc-shaped slit that opens on the upper surface, and a ring-shaped auxiliary bus bar is inserted into each of the slits. The auxiliary bus bar is used as a current supply path from the in-vehicle battery together with the bus bar.

That is, by using the annular bus bar as a current path from the power source or the battery to the power module, a small-sized and low-inductance inverter unit is realized.
JP 2005-005431 A

However, in the conventional “semiconductor device”, since the surface area of the connection part of the electronic circuit unit including the capacitor and the power transistor is small, it is inevitable that the inductance between the capacitor and the electronic circuit unit increases. .
An object of the present invention is to provide a power converter in which the inductance between the capacitor and the electronic circuit unit does not increase.

  In order to achieve the above object, a power converter according to the present invention is connected to a power source and is connected to a capacitor having two cylindrical terminal portions arranged coaxially and an electric drive unit, and is connected via the cylindrical terminal portion. And a plurality of power devices connected to each other.

  According to the present invention, the capacitor connected to the power supply has two cylindrical terminal portions arranged coaxially, and a plurality of power devices connected to the electric drive machine are capacitors via the cylindrical terminal portions. Connected to. For this reason, the inductance between the capacitor and the electronic circuit unit does not increase.

The best mode for carrying out the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a perspective view of a power converter according to the first embodiment of the present invention. As shown in FIG. 1, the power converter 10 includes a capacitor 11 and a plurality of power devices 12. The capacitor 11 is formed in a cylindrical shape by covering the wound dielectric member with a capacitor case 11a, and has a cylindrical cylindrical terminal portion 13 protruding from an end face on one end side in the axial direction. . Each power device 12 has a power device PN terminal 14, and is connected to the capacitor 11 via the power device PN terminal 14.

A motor 16 is connected to the power device output terminal 15 which is an output part of each power device 12, and an input bus bar 17 drawn from a power source (not shown) is connected to an input terminal 18 of the capacitor 11. . The power converter 10 converts the electric power input via the input bus bar 17 and outputs the electric power to the motor 16 to drive the motor 16, for example, an automobile electric drive machine.
FIG. 2 is an explanatory perspective view showing the internal structure of the capacitor shown in FIG. In the figure, the case, the lid, etc. of the capacitor are not shown, and the wound dielectric member is thicker than the actual one and the number of turns is significantly reduced (the same applies to FIGS. 3, 4 and 9). Is).

As shown in FIG. 2, the cylindrical terminal portion 13 has a P-side terminal (outer terminal) 13a located on the outer side and an N-side terminal (inner terminal) 13b located on the inner side, each having a different inner diameter. It is formed in a cylindrical shape and is arranged coaxially. That is, the capacitor 11 and the plurality of power devices 12 are connected via two terminals (P-side terminal 13a and N-side terminal 13b) arranged coaxially.
The dielectric member 19 wound into a cylindrical shape has an anode and a cathode (not shown) on each surface, and one end of each of the plurality of current leads 20 is connected to each of the anode and the cathode. The other ends of the plurality of current leads 20 are connected to the P-side terminal 13a and the N-side terminal 13b, respectively.

  Since the P-side terminal 13a and the N-side terminal 13b are formed in a cylindrical shape and are coaxially arranged, the width of the terminal portion is wide and the terminals 13a and 13b face each other, so that the inductance is large. Reduced. Moreover, the inductance from the connection part of each power device 12 and the cylindrical terminal part 13 to the capacitor | condenser 11 is uniform. For this reason, the bias of the surge voltage applied to each power device 12 is eliminated, and the operation reliability is improved. And considering the inductance between the respective parts of the P-side terminal 13a and the N-side terminal 13b, it is low and uniform, so that the plurality of current leads 20 have respective outer diameters of the P-side terminal 13a or the N-side terminal 13b. Are distributed on the circumference along the circumference.

  FIG. 3 is an enlarged perspective view showing the current lead of FIG. FIG. 4 is a perspective view showing another arrangement example of the current leads of FIG. As shown in FIG. 3, the current lead 20 includes an anode (+ side) lead 20 a connected to the anode of the dielectric member 19, an insulating lead 20 b, and a cathode (− side) connected to the cathode of the dielectric member 19. Since the anode lead 20a and the cathode lead 20c are arranged substantially in parallel with the insulating lead 20b, the inductance of the current lead 20 itself is reduced. Further, as shown in FIG. 4, if the current lead 20 has a configuration in which the anode lead 20a and the cathode lead 20c are alternately arranged, the insulating lead 20b is not required, so that it can be manufactured at low cost.

As the capacitor in this embodiment, for example, an aluminum electrolytic capacitor in which the P-side terminal and the N-side terminal can be easily taken out in the same direction is suitable, but other film capacitors, ceramic capacitors, etc. may be used. Good.
FIG. 5 is an explanatory view showing an example (part 1) of a suitable capacitor used in this embodiment. FIG. 6 is an explanatory diagram showing an example (part 2) of a suitable capacitor used in this embodiment. FIG. 7 is an explanatory view showing an example (part 3) of a suitable capacitor used in this embodiment.

  As shown in FIG. 5, when the capacitor 25 is formed with terminal portions on the upper and lower surfaces of the winding shaft of the dielectric member, for example, like a film capacitor, it is cylindrical on the inner side with respect to the capacitor case 26. The P-side terminal 27a is formed on the outer side, and the N-side terminal 27b in which the cylindrical portion and the annular portion of the outward flange shape are integrated is formed, and an insulating member is formed outside the N-side terminal 27b. An insulating holder 28 may be provided. The N-side terminal 27b is formed so as to cover the entire outer surface of the P-side terminal 27a. The insulating holder 28 functions as a terminal fixing member that fixes the current lead 20 and the cylindrical terminal portion 13, and the insulating holder 28 is fixed by the capacitor case 26.

  As shown in FIG. 6, the capacitor 30 includes the radiation fins 31 over the entire outer surface side of the outer terminal (for example, the N-side terminal 27 b) of the cylindrical terminal portion 13. The radiating fins 31 may be provided on either or both of the inner surface side of the cylindrical terminal portion 13 (for example, the P-side terminal 27a) and the outer surface side of the outer terminal (for example, the N-side terminal 27b). . Further, by mounting the heat dissipating fins 31 on the outer peripheral portion of the capacitor, for example, the outer surface portion of the N-side terminal 27b (see FIG. 5) of the capacitor 25, both strength improvement and heat dissipation improvement can be achieved. Even if a plurality of multilayer ceramic capacitors (not shown) are arranged radially in the capacitor case 32, the same configuration can be obtained.

As shown in FIG. 7, the capacitor 35 is formed by arranging a cylindrical P-side terminal 37a inside the capacitor case 36 and an N-side terminal 37b further inside the P-side terminal 37a. The capacitor case 36, the P-side terminal 37a, and the N-side terminal 37b are arranged concentrically from the outside in the order of description, so that the capacitor case 36 itself can be fixed without an insulating holder.
(Second Embodiment)

FIG. 8 is a perspective view of a power converter according to the second embodiment of the present invention. FIG. 9 is a perspective view of the capacitor of FIG. In FIG. 8, only one cylindrical terminal portion formed at one end of the capacitor is shown in the two cylindrical terminal portions, and the other cylindrical terminal portion formed at the other end of the capacitor. Is not shown.
As shown in FIGS. 8 and 9, the power converter 40 includes a capacitor 43 (see FIG. 9) provided with cylindrical terminal portions 41 and 42 at both ends, and a plurality of power converters disposed inside and outside the capacitor 43, respectively. Power device 44 and a plurality of power devices 45. Other configurations and operations are the same as those of the power converter 10 according to the first embodiment.

That is, the capacitor 43 has terminal portions 41 and 42 (see FIG. 9) projecting from both sides in the axial direction of the dielectric member 43a formed in a cylindrical shape by winding, that is, both ends of the capacitor. In addition, the capacitor 11 (see FIG. 2) is formed in a shape in which the dielectric member 19 is common and back to back (see FIG. 9).
A plurality of power devices 44 are arranged in an annular shape inside the capacitor 43 and a plurality of power devices 45 are arranged in an annular shape outside the capacitor 43 with the capacitor 43 interposed therebetween. A plurality of power devices 44 and a plurality of power devices 45 arranged in an annular shape are arranged concentrically on the radially inner side and the outer side of the capacitor 43.

  The capacitor 43 is connected to the plurality of power devices 44 and the plurality of power devices 45 via power device PN terminals 46 and 47, and the power device 45 is connected to the motor 49 via a power device output terminal 48. ing. An input bus bar (not shown) drawn from a power supply unit (not shown) such as a battery is connected to the input terminal 50 of the capacitor 43. The power device PN terminals 46 and 47 are formed in a flat plate shape, and are arranged in a substantially parallel double annular shape along the arrangement direction of the power devices 45, which are arranged radially inside and outside the power converter 40. .

Thus, by providing the cylindrical terminal portions 41 and 42 at both ends of the capacitor 43 and increasing the area of the cylindrical terminal portion, the connection area between the plurality of power devices 44 and the plurality of power devices 45 and the capacitor 43 is wide. Thus, a low inductance connection is possible. Further, by arranging the plurality of power devices 44 and the plurality of power devices 45 on the inner and outer periphery of the capacitor 43, the length of the motor (electric drive) 49 in the rotation axis direction can be shortened.
(Third embodiment)

FIG. 10 is a perspective view of a power converter according to the third embodiment of the present invention. As shown in FIG. 10, the power converter 50 includes a capacitor 43 (see FIG. 9) having cylindrical terminal portions 41 and 42 at both ends, and a plurality of power devices 51 respectively disposed at both ends of the capacitor 43. And a plurality of power devices 52. Other configurations and operations are the same as those of the power converter 10 according to the first embodiment.
That is, the capacitor 43 has terminal portions 41 and 42 protruding from both sides in the axial direction of the dielectric member 43a formed in a cylindrical shape by winding, that is, both ends of the capacitor. 2) (see FIG. 2).

  A plurality of power devices 51 are annularly formed along the outer periphery of the capacitor 43 on one end side in the axial direction of the capacitor 43 with the capacitor 43 interposed therebetween, and a plurality of power devices 52 are provided on the other end side in the axial direction of the capacitor 43. They are arranged in an annular shape along the outer periphery of the capacitor 43. The capacitor 43, the plurality of power devices 51 and the plurality of power devices 52 are connected via power device PN terminals 53 and 54. The power device 51 is connected to the power device output terminal 55, and the power device 52 is connected to the power device 52. Each device output terminal 56 is connected to the motor 49. An input bus bar (not shown) drawn from a power supply unit (not shown) such as a battery is connected to the input terminal 57 of the capacitor 43.

As described above, by selecting the arrangement of the power devices 51 and 52 like the power converter 40 (see FIG. 8) or the power converter 50 (see FIG. 10) according to the shape of the motor 49, the optimal electric drive A drive machine can be comprised.
As described above, the capacitor fixes the cylindrical terminal portion, the dielectric member formed by winding with the cathode and the anode, and the current lead and the cylindrical terminal portion that connect the cylindrical terminal portion from the cathode and the anode. Insulating terminal fixing member (insulating holder) and a case (capacitor case) for fixing the terminal fixing member, the negative current lead connected to the cathode and the positive current lead connected to the anode are spiral Alternatively, they are alternately arranged in a circumferential shape. As a result, since the current leads from a wide area of the capacitor are connected to the cylindrical terminal portion, the inductance from each power device to the capacitor becomes uniform, and current imbalance can be avoided.

Further, in the above configuration, by arranging the − side current lead and the + side current lead so as to overlap each other through the insulating member, both the + side current lead and the − side current lead in the capacitor are overlapped, so that the inductance of the capacitor itself is reduced. Can be reduced.
Further, in the above configuration, by arranging the current leads on both the upper and lower sides in the winding axis direction of the dielectric member, low inductance connection can be made with a large number of power devices.
In the above configuration, the creeping distance between the anode and the cathode can be secured by increasing the area of the dielectric member relative to the area of the cathode foil forming the cathode and the anode foil forming the anode. Insulation between the current lead and the negative current lead can be easily taken.

  In addition, the capacitor is formed of a cylindrical body, and has one of the cylindrical terminal portions on the inner side surface of the cylindrical body. That is, the capacitor is hollow and the terminal portion is provided on the inner peripheral surface, so that the central axis can be used effectively. In addition, the size can be reduced. In addition, by providing cylindrical terminal portions at both ends of the cylindrical capacitor, the power device can be connected with low inductance in the axial direction of the capacitor, so that the outer diameter of the power converter is reduced. Can do.

Further, when the outer diameter of this capacitor is R2 and the outer diameter of the cylindrical terminal portion is R1, the relationship between R2 and R1 is 0.5 × R2 <R1 <R2, so that the terminal is closer to the outer periphery of the capacitor. Since the portion is located, the area of the terminal portion is increased, the connection area with the power device is increased, and the inductance between the power device and the capacitor can be reduced. Further, by providing one of the cylindrical terminal portions on the outer peripheral surface of the capacitor made of a cylindrical body, the terminal portion area can be increased, so that the heat radiation of the capacitor and the power device is improved.
In addition, the capacitor is formed of a cylinder or a column, and a plurality of power devices are arranged on at least one of the inner peripheral surface and the outer peripheral surface of the cylinder or the column, thereby shortening the axial length of the power converter. Can do. Further, the outer diameter of the power converter can be reduced by arranging a plurality of power devices on at least one of one end and both ends in the axial direction of the cylinder or column of the capacitor.

  In addition, since the power device includes the P terminal and the N terminal arranged side by side on the inner side and the outer side in the converter radial direction, the inductance of the power device itself can be reduced. The power device includes a P terminal and an N terminal, and the curvature of the P terminal is the diameter of the inner terminal of the cylindrical terminal portion, and the curvature of the N terminal is the diameter of the inner terminal of the cylindrical terminal portion. By being overlapped and connected to the cylindrical terminal portion, the curvature of the cylindrical terminal portion and the curvature of the power device terminal portion become the same, so the connection reliability between the power device and the capacitor is improved.

  In addition, since at least one of the inner terminal and the outer terminal of the cylindrical terminal part is connected to the cooling part via an insulating member having good thermal conductivity, the cylindrical terminal part can be used as a heat dissipation member. The cooling capacity of the power converter is improved. Also, by making the thicknesses of the outer terminal (P side terminal) and the inner terminal (N side terminal) of the cylindrical terminal portion different, the thicker one of the outer terminal and the inner terminal is used as the strength member. As a result, the vibration resistance is improved. In addition, by providing a radiation fin on at least one of the inner side of the inner terminal and the outer side of the cylindrical terminal part, the terminal part faces, and the radiation fin is arranged on one side opposite to the terminal part, Low inductance and high heat dissipation can be achieved.

It is a perspective view of the power converter concerning a 1st embodiment of this invention. FIG. 2 is a perspective explanatory view showing an internal structure of the capacitor of FIG. 1. It is a perspective view which expands and shows the current lead of FIG. FIG. 6 is a perspective view showing another example of arrangement of the current leads in FIG. 2. It is explanatory drawing which shows the example (the 1) of the suitable capacitor | condenser used in this embodiment. It is explanatory drawing which shows the example (the 2) of the suitable capacitor | condenser used in this embodiment. It is explanatory drawing which shows the example (the 3) of the suitable capacitor | condenser used in this embodiment. It is a perspective view of the power converter which concerns on 2nd Embodiment of this invention. It is a perspective view of the capacitor | condenser of FIG. It is a perspective view of the power converter which concerns on 3rd Embodiment of this invention.

Explanation of symbols

10, 40, 50 Power converter 11, 25, 30, 35, 43 Capacitor 11a, 26, 32, 36 Capacitor case 12, 44, 45, 51, 52 Power device 13, 41, 42 Cylindrical terminal portion 13a, 27a , 37a P-side terminal 13b, 27b, 37b N-side terminal 14, 46, 47, 53, 54 Power device PN terminal 15, 48, 55, 56 Power device output terminal 16, 49 Motor 17 Input bus bar 18, 50, 57 Input Terminals 19, 43a Dielectric member 20 Current lead 20a Anode lead 20b Insulating lead 20c Cathode lead 28 Insulating holder 31 Radiation fin

Claims (16)

A capacitor connected to a power source and having a cylindrical terminal portion comprising two terminals arranged coaxially;
A power converter comprising: a plurality of power devices connected to the capacitor via the cylindrical terminal portion and connected to an electric drive.   The power converter according to claim 1, wherein the inductance from each power device and the connection portion of the cylindrical terminal portion to the capacitor is made uniform. The capacitor includes the cylindrical terminal portion, a dielectric member formed by being provided with a cathode and an anode, a current lead connecting the cylindrical terminal portion from the cathode and the anode, and the cylindrical terminal portion. An insulating terminal fixing member for fixing, and a case for fixing the terminal fixing member;
The power converter according to claim 1 or 2, wherein a negative current lead connected to the cathode and a positive current lead connected to the anode are alternately arranged in a spiral shape or a circumferential shape.   The power converter according to claim 3, wherein the − side current lead and the + side current lead are arranged so as to overlap each other via an insulating member.   The power converter according to claim 3 or 4, wherein the current leads are arranged on both sides of the dielectric member in the winding axis direction.   The power converter according to any one of claims 3 to 5, wherein an area of the dielectric member is larger than an area of the cathode foil forming the cathode and the anode foil forming the anode.   The power converter according to any one of claims 1 to 6, wherein the capacitor is formed of a cylindrical body and includes one of the cylindrical terminal portions on an inner surface of the cylindrical body.   The power converter according to any one of claims 1 to 6, wherein the capacitor is formed of a cylindrical body, and the cylindrical terminal portions are provided at both axial ends of the cylindrical body.   When the capacitor is formed of a cylinder or a column, the outer diameter of the capacitor is R2, and the outer diameter of the cylindrical terminal portion is R1, the relationship between R2 and R1 is 0.5 × R2 <R1 <R2. The power converter according to any one of claims 1 to 8.   The electric power according to any one of claims 1 to 9, wherein the capacitor is formed of a cylinder or a column, and a plurality of the power devices are arranged on at least one of an inner peripheral surface and an outer peripheral surface of the cylinder or the column. converter.   The power conversion according to any one of claims 1 to 10, wherein the capacitor is formed of a cylinder or a column, and a plurality of the power devices are arranged at at least one of one end and both ends in the axial direction of the cylinder or the column. vessel.   The power converter according to any one of claims 1 to 11, wherein the power device includes a P terminal and an N terminal arranged side by side in the converter radial direction inside and outside.   The power device includes a P terminal and an N terminal, and the curvature of the P terminal is a diameter of the inner terminal of the cylindrical terminal portion, and the curvature of the N terminal is a diameter of the inner terminal of the cylindrical terminal portion, and each is constant. The power converter according to any one of claims 1 to 12, wherein the power converter is overlapped and connected to the cylindrical terminal portion.   The power converter according to any one of claims 1 to 13, wherein at least one of the inner terminal and the outer terminal of the cylindrical terminal part is connected to the cooling part via an insulating member having good thermal conductivity.   The power converter according to any one of claims 1 to 14, wherein an inner terminal and an outer terminal of the cylindrical terminal portion have different thicknesses.   The power converter as described in any one of Claims 1-15 provided with a radiation fin in at least one of the inner side of the inner side terminal of the said cylindrical terminal part, and the outer side of an outer side terminal.

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