JP2006197735A - Inverter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a small inverter by dispensing with a snubber capacitor constituting a snubber circuit, and improving its reliability by the reduction of the number of components, and enabling the cost reduction. <P>SOLUTION: Smoothing capacitors 8-10 are made by mounting a plurality of small-sized electrolytic capacitors 33 on a printed board 32, and also the electric connection part between each small-sized electrolytic capacitor 33 and an inverter main circuit 17 is mounted on the printed board 32. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an inverter device used for general-purpose inverters, elevators, electric vehicles, hybrid electric vehicles and the like.

  In Patent Document 1, an IGBT chip, an electrolytic capacitor chip, a micro conveyor chip, and a control power supply circuit chip are mounted on one water-cooled heat sink to improve cooling efficiency, and electrolytic capacitors and IGBTs are alternately arranged, The wiring inductance is reduced and the snubber circuit is eliminated. In Patent Document 2, in an inverter device in which an inverter main circuit made of IGBT is connected to an electrolytic capacitor for smoothing DC power, each electrolytic capacitor and each positive terminal of the IGBT are arranged in a circular wiring pattern at equal intervals in the circumferential direction. In addition, the negative terminals of the electrolytic capacitor and IGBT are connected to other circular wiring patterns at equal intervals in the circumferential direction, the wiring pattern is shortened to reduce its inductance, and the surge during switching of the IGBT It is shown that an inverter device can be miniaturized by reducing the capacity of a snubber capacitor that absorbs voltage.

  In Patent Document 3, a first substrate having conductive plates insulated from each other and a second substrate having wirings insulated from each other are provided, and one conductive plate and one wiring are connected by a first conductor. The other conductive plate and the other wiring are connected by the second conductor, the first substrate is connected to the conductive plate and an electrolytic capacitor is provided, and the second substrate is connected to the wiring. A servo amplifier provided with a semiconductor module and a snubber capacitor, which reduces the impedance between the semiconductor module and the snubber capacitor, reduces the surge voltage when the IGBT constituting the semiconductor module is turned off, and performs IGBT short-circuit protection It is shown.

  Here, an example of a circuit configuration of a conventional inverter device will be described with reference to FIG. In the figure, 1 is an inverter device, the AC input terminal of the rectifier circuit 2 is connected to the AC power source 3, and the DC output terminal of the rectifier circuit 2 is connected to the wiring patterns 6 and 7 via the DC power source buses 4 and 5. Between the wiring patterns 6 and 7, smoothing capacitors 8 to 10 made of three electrolytic capacitors are connected in parallel. In addition, IGBTs 11 to 16 as switching elements are connected between the wiring patterns 6 and 7 by a three-phase bridge to constitute an inverter main circuit 17. In this case, the collector terminals 11c, 13c, and 15c of the IGBTs 11, 13, and 15 are connected to the wiring pattern 6, the emitter terminals 12e, 14e, and 16e of the IGBTs 12, 14, and 16 are connected to the wiring pattern 7, and the U-phase, V-phase and W-phase arms 18 to 20 are formed.

  The emitter terminals 11 e, 13 e, 15 e of the IGBTs 11, 13, 15 and the collector terminals 12 c, 14 c, 16 c of the IGBTs 12, 14, 16 are connected by wiring patterns 21 to 23 and connected to the motor 24. Moreover, each gate terminal 11g-16g of IGBT11-16 is connected to the microcomputer 25 as a control circuit. Further, flywheel diodes 11a to 16a are connected between collector terminals 11c to 16c and emitter terminals 11e to 16e of IGBTs 11 to 16, respectively, and snubber capacitors 26 to 26 constituting a snubber circuit are respectively connected to the arms 18 to 20. 28 are connected in parallel.

  Next, the operation of the above configuration will be described. When AC power is supplied from the AC power supply 3 to the rectifier circuit 2, the AC power is rectified to generate DC power, and the DC power is generated from the rectifier circuit 2 to the smoothing capacitors 8-10. When power is supplied, the DC power is smoothed, and the smoothed DC power is supplied to the inverter main circuit 17. Then, the DC power supplied to the inverter main circuit 17 is switched and converted into AC power when a gate signal is supplied from the microcomputer 25 to the IGBTs 11 to 16, and is output to the motor 24. The motor 24 is driven. The The snubber capacitors 26 to 28 constituting the snubber circuit are provided to prevent a surge voltage from being generated during the switching operation of the IGBTs 11 to 16 and the IGBTs 11 to 16 from being destroyed.

FIG. 3 is a perspective view of the main components constituting the above circuit. The wiring patterns 6 and 7 are made of copper bars, and the snubber capacitors 26 to 28 are provided with a film capacitor 30 for three phases on the printed board 29. The smoothing capacitors 8 to 10 for each phase, the inverter main circuit 17 in which the IGBTs 11 to 16 are bridge-connected, and the snubber capacitors 26 to 28 for each phase are connected between the wiring patterns 6 and 7 by screws 31 or the like. Is done.
Japanese Patent Laid-Open No. 11-18429 JP-A-11-27959 JP 2003-219661 A

  By the way, in the conventional inverter device shown in FIGS. 2 and 3, the magnitude of the surge voltage generated when the IGBTs 11 to 16 are switched is that of the wiring patterns 6 and 7 between the smoothing capacitors 8 to 10 and the IGBTs 11 to 16. Since it is determined by the inductance, the surge voltage can be reduced as the length of the wiring patterns 6 and 7 between them is shorter. However, since the conventional smoothing capacitors 8 to 10 are of the screw terminal type, the diameter is large and the stationary smoothing capacitors 8 to 10 are of the stationary type. Therefore, the wiring patterns 6 and 10 between the smoothing capacitors 8 to 10 and the IGBTs 11 to 16 are used. 7, the surge voltage at the time of switching of the IGBTs 11 to 16 was increased. For this reason, large-capacity snubber capacitors 26 to 28 are required to suppress the surge voltage, and the reliability is lowered due to an increase in the number of parts and the cost is increased.

  The present invention has been made to solve the above-described problems, and reduces the surge voltage at the time of switching of the inverter main circuit by reducing the inductance between the smoothing capacitor and the inverter main circuit. The object is to eliminate the snubber capacitor that constitutes the above, improve the reliability by reducing the number of parts, reduce the cost, and obtain a small inverter device.

  An inverter device according to claim 1 of the present invention includes a smoothing capacitor that smoothes DC power, a plurality of switching elements that are bridge-connected, and an inverter main circuit that is connected to the smoothing capacitor. The smoothing capacitor is formed by mounting a plurality of small electrolytic capacitors on a printed board, and the electrical connection portion between each small electrolytic capacitor and the inverter main circuit is mounted on the printed board.

  As described above, according to the present invention, a smoothing capacitor for each phase is formed by a plurality of small electrolytic capacitors mounted on a printed board, and an electrical connection portion between each small electrolytic capacitor and the inverter main circuit is mounted on the printed board. The electrical connection portion can be shortened, the surge voltage at the switching operation of the switching elements constituting the inverter main circuit can be reduced, and a snubber comprising a snubber capacitor for suppressing the surge voltage is provided. Circuits can be eliminated, reliability can be improved by reducing the number of components, costs can be reduced, and the inverter device can be miniaturized.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the main configuration of an inverter device according to the best mode of the present invention. Four smoothing capacitors 8 to 10 for U, V, and W phases are mounted on a printed board 32, respectively. The inverter main circuit 17 formed by the small electrolytic capacitor 33 and configured by bridge-connecting the switching elements 11 to 16 is attached to the printed board 32 with the screw 34, and the electrical connection between the smoothing capacitors 8 to 10 and the inverter main circuit 17 is achieved. Such a connecting portion is mounted on the printed board 32. Other configurations are the same as those in the circuit diagram of FIG. 2 except for the snubber capacitors 26 to 28.

  In the above-described best embodiment, the smoothing capacitors 8 to 10 for each phase are formed by a plurality of small electrolytic capacitors 33 mounted on the printed board 32, and electrical connection portions between the small electrolytic capacitors 33 and the inverter main circuit 17 are formed. Is mounted on the printed circuit board 32, the electrical connection between each small electrolytic capacitor 33 and the inverter main circuit 17 can be shortened, and the surge voltage generated during the switching operation of each IGBT 11-16 can be reduced. In addition, a snubber circuit composed of a snubber capacitor for suppressing the surge voltage can be eliminated. For this reason, the reliability can be improved by reducing the number of parts, the cost can be reduced, and the inverter device can be miniaturized.

1 is a perspective view showing a main configuration of an inverter device according to an embodiment of the present invention. It is a circuit block diagram of the conventional inverter apparatus. It is a perspective view of the main components of the conventional inverter apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Inverter apparatus 2 ... Rectifier circuit 6, 7, 21-23 ... Wiring pattern 8-10 ... Smoothing capacitor 11-16 ... IGBT
17 ... Inverter main circuit 25 ... Microcomputer 32 ... Printed board 33 ... Small electrolytic capacitor

Claims (1)

In an inverter device comprising a smoothing capacitor that smooths DC power and a plurality of switching elements connected in a bridge, and an inverter main circuit connected to the smoothing capacitor, a plurality of small electrolytic capacitors are printed on the smoothing capacitor. An inverter device characterized in that it is mounted on a board and an electrical connection portion between each small electrolytic capacitor and the inverter main circuit is mounted on a printed board.

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