JP2005341643A - Bus bar apparatus of power converter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily change a circuit and a circuit constant and fully suppress noise and EMI (electromagnetic interference) due to switching, while a bus bar has the functions of a capacitor and a coil and a small size. <P>SOLUTION: In a bus bar apparatus of a power converter, at least one pair of the bus bars 12, 14 are integrated; a switching element 10 is connected between a pair of the bus bars; power is transmitted to and received from the switching element through the bus bars; a capacitor circuit 18 is disposed between a pair of the bus bars and has a plurality of laminated unit capacitors 24, whose dielectric film 23 is inserted between a lower conductor 21 and an upper conductor 22; the lower conductor is connected to one bus bar; and the upper conductor is connected to the other bus bar. Alternatively, the lower conductor can be integrally formed with one bus bar, and the upper conductor can be formed integrally with the other bus bar. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a bus bar device of a power converter for transmitting and receiving power to and from a power converter in which a switching element that performs switching at high frequency is incorporated.

  Semiconductor power converters using voltage-driven semiconductor elements such as insulated gate bipolar transistors (IGBTs) are widely used. This semiconductor power converter has a function of converting DC power into AC power by turning on and off a switching element incorporated therein at a predetermined switching frequency.

  Since the output voltage of the semiconductor power converter has a voltage waveform obtained by switching a DC voltage, it includes a frequency component corresponding to the switching frequency. Since this frequency component gives stress to a motor or the like as a load of the power converter, the power converter uses a filter circuit to remove the frequency component.

  Further, in order to suppress noise and EMI (electromagnetic interference) due to switching, a snubber circuit as a peripheral circuit is connected to the switching element. Thereby, noise and EMI (electromagnetic interference) can be reduced.

  However, the above-described filter has a large volume and a large power converter. Therefore, in order to reduce the size, the filter is downsized by increasing the switching frequency and the snubber circuit as a peripheral circuit is omitted.

  However, in a power converter to which no peripheral circuit is added, it is difficult to suppress switching noise and EMI (electromagnetic interference). Further, in the conventional snubber circuit, inductance and resistance due to wiring are also generated.

  Thus, for example, Patent Document 1 proposes a method of efficiently absorbing high-frequency noise by pressing and holding a capacitor with a bus bar. FIG. 10 shows how the proposed capacitor is attached to the bus bar. A pair of bus bars 1 and 2 are disposed outside the electrodes 4 and 5 on both sides of the capacitor 3, and the capacitor 3 is pressed and clamped by a pair of bolts 6 and nuts 7 from the outside of the pair of bus bars 1 and 2.

Thereby, the noise and EMI (electromagnetic interference) by switching can be suppressed with the size kept small.
Japanese Patent Laid-Open No. 7-211585

  However, the above-described method shown in FIG. 10 in which the function of the capacitor and coil is given to the bus bar also has the following problems to be improved.

  That is, since the bus bar has functions of a capacitor and a coil, circuit constants such as capacitance and inductance are fixed, and it is difficult to change the circuit constant after the bus bar is attached to the power converter.

  The present invention has been made in view of such circumstances. With the bus bar having the functions of a capacitor and a coil, the size and size can be kept small, and the circuit and circuit constants can be easily changed. It is an object of the present invention to provide a bus bar device for a power converter that can sufficiently suppress noise and EMI (electromagnetic interference) due to noise.

  The present invention is applied to a bus bar device of a power converter in which at least a pair of bus bars are incorporated, a switching element is connected between the pair of bus bars, and power is transmitted to and received from the switching elements via each bus bar.

  In order to solve the above problems, in the present invention, a capacitor circuit in which a plurality of unit capacitors each having a dielectric film inserted between a lower conductor and an upper conductor are laminated is disposed between a pair of bus bars. Each lower conductor is connected to one bus bar, and each upper conductor is connected to the other bus bar.

  In the bus bar device of the power converter configured as described above, after each bus bar is attached to the power converter by changing the number of unit capacitors stacked to constitute the capacitor circuit incorporated between the pair of bus bars. The capacitance (capacitance) of the capacitor circuit can be easily and arbitrarily adjusted.

  According to another invention, in the above-described bus bar device for a power converter, a capacitor circuit in which a plurality of unit capacitors each having a dielectric film inserted between a lower conductor and an upper conductor are stacked is disposed between a pair of bus bars. Each lower conductor is integrally formed with one bus bar, and each upper conductor is integrally formed with the other bus bar.

  Thus, by forming the upper conductor and the lower conductor constituting each unit capacitor integrally with each bus bar, it is not necessary to match impedance between the capacitor circuit and each bus bar.

  According to another invention, in the bus bar device for the power converter of the above-described invention, the area of the upper conductor of each unit capacitor is set smaller than the area of the lower conductor, thereby improving the insulation between the bus bars. Yes.

  According to another invention, in the bus bar device of the power converter of the above-described invention, the capacitor circuit is disposed in the vicinity of the connection position of the switching element in each bus bar, so that noise or EMI (electromagnetic interference) due to switching is generated in the vicinity of the generation position. Can be surely reduced.

  According to another invention, in the bus bar device for the power converter of the above-described invention, the capacitance between bus bars, that is, between switching element terminals is adjusted more precisely by arranging a plurality of capacitor circuits between the bus bars. Is possible.

  Another invention is a bus bar device for a power converter according to the invention described above, wherein a conductive material is deposited on both surfaces of the dielectric film of each unit capacitor to thereby contact the dielectric film with the upper conductor and the lower conductor. It becomes possible to prevent the occurrence of bubbles and the like.

According to another invention, in the bus bar device for a power converter according to the invention described above, a magnetic film is formed on a part of the surface of at least one bus bar.
In the bus bar device of the power converter configured as described above, since the magnetic film is formed on the surface of the bus bar in addition to the capacitor circuit, an inductance component is equivalently incorporated into the bus bar. That is, the bus bar device of the present invention has a function of providing a capacitance in parallel with the switching element and a function of providing an inductance in series with the switching element.

  Thus, in the bus bar device of the power converter of the present invention, a capacitor circuit in which a plurality of unit capacitors each having a dielectric film inserted between a lower conductor and an upper conductor are stacked is disposed between a pair of bus bars. ing. Therefore, with the bus bar having the functions of the capacitor and the coil, the size and the circuit constant can be easily changed with the size kept small, and noise and EMI (electromagnetic interference) due to switching can be sufficiently suppressed.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
1 is a perspective view showing the overall configuration of the bus bar device of the power converter according to the first embodiment of the present invention, and FIG. 2 is an enlarged view showing the configuration of the capacitor circuit of the main part of the bus bar device. Is an equivalent circuit diagram.

  In FIG. 1, one end 12a of one bus bar 12 is fixed to the emitter terminal 11 (11a) of the switching element 10 by a fixture 20a. One end 14a of the other bus bar 14 is fixed to the collector terminal 13 of the switching element 10 by a fixture 20b. A capacitor circuit 18 is inserted between one end 12a and 12b of each bus bar 12 and 14.

  FIG. 2 is a side view showing a detailed configuration of the capacitor circuit 18 interposed between the bus bars 12 and 14. In this capacitor circuit 18, a plurality of unit capacitors 24 each having a dielectric film 23 inserted between a rectangular plate-like lower conductor 21 and a rectangular plate-like upper conductor 22 are laminated, and the upper and lower surfaces thereof are laminated. Support plates 25 a and 25 b are attached, and the support plates 25 a and 25 b are fixed by a pair of fasteners 26. Note that the area of the dielectric film 23 is set to be larger than the areas of the lower conductor 21 and the upper conductor 22 in order to ensure the withstand voltage between the lower conductor 21 and the upper conductor 22.

  The lower conductor 21 of each unit capacitor 24 is electrically and mechanically connected to one end 12a of one bus bar 12 by a connector 27a, and the upper conductor 22 of each unit capacitor 24 is connected to the one end 14a of the other bus bar 14 by a connector 27b. Connected electrically and mechanically. Therefore, the entire capacitance of the capacitor circuit 18 inserted between the bus bars 12 and 14 is a capacitance obtained by adding the capacitance of each unit capacitor 24.

  Further, as shown in FIG. 4, a magnetic film 19 is attached to the midway position of the bus bar 14 attached to the collector terminal 13. Thus, by sticking the magnetic film 19 to the bus bar 14, an inductance function in which a coil is equivalently incorporated can be added to the bus bar 14 itself. The magnitude of the inductance can be easily adjusted by increasing or decreasing the area of the magnetic film 19 as shown in FIG.

  Therefore, the bus bar device according to the first embodiment includes a pair of bus bars 12 and 14, a capacitor circuit 18, and a magnetic film 19.

  In the equivalent circuit of the bus bar device of the power converter shown in FIG. 3, the capacitor circuit 18 and the flywheel diode 17 described above are connected between the collector terminal 13 and the emitter terminal 11 of the switching element 10. Further, the collector terminal 13 is connected to a coil 19 a that is equivalently formed of a magnetic film 19 attached to the bus bar 14. A bus bar 12 is connected to the emitter terminal 11. A gate resistor 16 is connected to the gate terminal 15.

  In the power converter having such a circuit configuration, when power is applied from the bus bar 12 to the bus bar 14 via the switching element 10, a drive signal is applied to the gate terminal 15 via the gate resistor 16 (in FIG. 1). Between the gate terminal 15 and the emitter terminal 11a), the switching element 10 is turned on and off. However, the current flowing abruptly increases at turn-on, and a surge voltage is generated between the terminals of the switching element 10 at turn-off. This generates noise and EMI (electromagnetic interference). Therefore, an increase in current when the coil 19a is turned on can be suppressed. Further, the surge voltage at the time of turn-off is suppressed by the capacitor circuit 18.

  In the bus bar device of the power converter according to the first embodiment configured as described above, the capacitance of the capacitor circuit 18 provided in parallel with the switching element 10 by the pair of bus bars 12 and 14 is as follows. As shown in FIG. 2, by changing the number of unit capacitors 24 constituting the capacitor circuit 18, noise and EMI (electromagnetic interference) can be easily generated even after the bus bar device is attached to the power converter. It is possible to change and adjust the optimum value to the minimum.

  Similarly, in the magnetic film 19 affixed to the bus bar 14, the inductance of the coil 19a provided in series with the switching element 10 is increased or decreased by increasing or decreasing the area of the magnetic film 19 as shown in FIG. Even after the bus bar device is attached to the power converter, it is possible to easily change and adjust the optimum value to minimize noise and EMI (electromagnetic interference).

  In this way, with the bus bar 12 and 14 having the functions of the capacitor circuit 18 and the coil 19a, it is possible to easily change circuit constants such as capacitance and inductance while keeping the bus bar device small. It is possible to sufficiently suppress noise and EMI (electromagnetic interference) generated due to.

  The present invention is not limited to the first embodiment described above. In the bus bar device of the power converter of the first embodiment, the lower conductor 21 of each unit capacitor 24 of the capacitor circuit 18 is electrically and mechanically connected to one end 12a of one bus bar 12 by a connector 27a. The upper conductor 22 of the capacitor 24 is electrically and mechanically connected to one end 14a of the other bus bar 14 by a connector 27b.

  However, the lower conductor 21 of each unit capacitor 24 can be integrally formed with one bus bar 12, and the upper conductor 22 of each unit capacitor 24 can be integrally formed with the other bus bar 14. Thus, it is necessary to achieve impedance matching between the capacitor circuit 18 and each bus bar 12, 14 by integrally forming the upper conductor 21 and the lower conductor 22 constituting each unit capacitor 24 with each bus bar 12, 14. Absent. In this case, the capacitance of the entire capacitor circuit 18 is adjusted by inserting or removing the dielectric film 23 of each unit capacitor 24.

(Second Embodiment)
FIG. 6 is a perspective view showing the overall configuration of the bus bar device of the power converter according to the second embodiment of the present invention. The same parts as those in the bus bar device of the power converter according to the first embodiment shown in FIG.

  In the bus bar device of the power converter according to the second embodiment, one end 12 a of the bus bar 12 fixed to the emitter terminal 11 of the switching element 10 and one end 14 a of the bus bar 14 fixed to the collector terminal 13 of the switching element 10. Between the two capacitor circuits 18 and 18a. The two capacitor circuits 18 and 18a have substantially the same configuration as the capacitor circuit 18 in the bus bar device of the first embodiment described with reference to FIG.

  As described above, by disposing the plurality of capacitor circuits 18 and 18a between the bus bars 12 and 14, the capacitances can be changed and adjusted by the capacitor circuits 18 and 18a alone. As a result, the capacitance between the bus bars 12 and 14, that is, the capacitance between the emitter terminal 11 and the collector terminal 13 of the switching element 10 can be adjusted more precisely.

  Further, it becomes possible to share the necessary capacitance between the terminals of the switching element 10 for each capacitor circuit 18, 18 a, the number of unit capacitors 24 of each capacitor circuit 18, 18 a can be reduced, and each capacitor circuit 18 and 18a can be reduced in size. As a result, the thickness of the entire bus bar device can be made uniform, and the bus bar device can be further reduced in size.

(Third embodiment)
FIG. 7 is a diagram showing extracted main portions of the bus bars 12 and 14 and the capacitor circuit 18 in the bus bar device of the power converter according to the third embodiment of the present invention. Since the configuration other than the capacitor circuit 18 is substantially the same as that of the bus bar device of the power converter according to the first embodiment shown in FIG.

  In the capacitor circuit 18 of the bus bar device of the power converter according to the third embodiment, the dielectric film 23 is inserted between the lower conductor 21 and the upper conductor 22 basically as described with reference to FIG. A plurality of unit capacitors 24 are stacked. As shown in the schematic diagram of FIG. 8, the area (width) of the upper conductor 22 of each unit capacitor 24 is set smaller than the area (width) of the lower conductor 21. The area (width) of the dielectric film 22 is set substantially equal to the area (width) of the lower conductor 21.

  In the bus bar device of the third embodiment configured as described above, the insulation between the bus bars 12 and 14 can be improved without increasing the area (width) of the dielectric film 22 in each unit capacitor 24. . Therefore, as a result, the bus bar device can be formed in a small size while securing the capacitor capacity.

(Fourth embodiment)
FIG. 9A is a side view showing a detailed configuration of the capacitor circuit 18 interposed between the bus bars 12 and 14 in the bus bar device of the power converter according to the fourth embodiment of the present invention. Since the configuration other than the capacitor circuit 18 is substantially the same as that of the bus bar device of the power converter according to the first embodiment shown in FIG.

  In the capacitor circuit 18 in the bus bar device according to the fourth embodiment, as described basically with reference to FIG. 2, the unit capacitor 24 in which the dielectric film 23 is inserted between the lower conductor 21 and the upper conductor 22 is provided. A plurality of layers are stacked. As shown in FIG. 9B, a conductive material 28 is deposited on the upper surface of each dielectric film 23 that contacts the lower conductor 21 and the lower surface that contacts the upper conductor 22.

  Thus, by depositing the conductive material 28 on both surfaces of the dielectric film 23 of each unit capacitor 24, the contact surface between the dielectric film 23 and the upper conductor 22 and the lower conductor 21 becomes flat, and the contact surface becomes It is possible to prevent bubbles and the like from occurring, prevent early deterioration of the unit capacitor 24, and stabilize circuit constants such as capacitance in the capacitor circuit 18.

The perspective view which shows the whole structure of the bus bar apparatus of the power converter concerning 1st Embodiment of this invention. The side view which shows the structure of the capacitor circuit integrated in the bus bar apparatus of the power converter of the embodiment Equivalent circuit diagram of bus bar device of power converter of same embodiment The figure which shows the bus bar and magnetic film which were integrated in the bus bar apparatus of the power converter of the embodiment The figure which shows the bus bar and magnetic film which were similarly integrated in the bus bar apparatus of the power converter of the embodiment The perspective view which shows the whole structure of the bus bar apparatus of the power converter concerning 2nd Embodiment of this invention. The figure which extracts and shows the principal part of each bus bar and capacitor circuit of the bus bar apparatus of the power converter concerning 3rd Embodiment of this invention. The schematic diagram which shows the structure of the capacitor circuit integrated in the bus bar apparatus of the power converter of the embodiment The figure which shows the structure of the capacitor circuit integrated in the bus-bar apparatus of the power converter concerning 4th Embodiment of this invention. A diagram showing the mounting state of the conventional capacitor to the bus bar

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Switching element, 11 ... Emitter terminal, 12, 14 ... Bus bar, 13 ... Collector terminal, 15 ... Gate terminal, 16 ... Gate resistance, 17 ... Flywheel diode, 18, 18a ... Capacitor circuit, 19 ... Magnetic film, 19a ... Coil, 21 ... Lower conductor, 22 ... Upper conductor, 24 ... Unit capacitor, 27a, 27b ... Connector, 28 ... Conductive material,

Claims (7)

In a bus bar device of a power converter in which at least a pair of bus bars is incorporated, a switching element is connected between the pair of bus bars, and power is transmitted to and received from the switching element via each bus bar.
A capacitor circuit in which a plurality of unit capacitors each having a dielectric film inserted between a lower conductor and an upper conductor are stacked is disposed between the pair of bus bars, and each lower conductor is connected to one bus bar, A bus bar device for a power converter, wherein the upper conductor is connected to the other bus bar. In a bus bar device of a power converter in which at least a pair of bus bars is incorporated, a switching element is connected between the pair of bus bars, and power is transmitted to and received from the switching element via each bus bar.
A capacitor circuit in which a plurality of unit capacitors each having a dielectric film inserted between a lower conductor and an upper conductor is laminated between the pair of bus bars is disposed, and each lower conductor is integrally formed with one bus bar, A bus bar device for a power converter, wherein each upper conductor is integrally formed with the other bus bar.   The bus bar device for a power converter according to claim 1 or 2, wherein an area of the upper conductor is smaller than an area of the lower conductor.   4. The bus bar device for a power converter according to claim 1, wherein the capacitor circuit is disposed in the vicinity of a connection position of the switching element in each bus bar. 5.   The bus bar device for a power converter according to any one of claims 1 to 4, wherein a plurality of the capacitor circuits are disposed between the pair of bus bars.   The bus bar device for a power converter according to any one of claims 1 to 5, wherein a conductive material is deposited on both surfaces of the dielectric film.   7. The bus bar device for a power converter according to claim 1, wherein a magnetic film is formed on a part of the surface of at least one bus bar.

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