JP2011199917A - Power converter for rolling stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an LC filter for preventing inverter control from being affected even when the capacity of a filter capacitor is increased.SOLUTION: Power converter for rolling stocks includes a gate control circuit for supplying a gate signal to a semiconductor element, and a filter capacitor connected to a DC terminal of a power conversion circuit for smoothing a DC current. A separate capacitor for preventing false detection of a track circuit is connected to the power converter with an impedance not less than a certain value. In the power converter, the semiconductor element and the filter capacitor are stored in a common casing, and the filter capacitor and the semiconductor element are fixed mutually to form an integral structure. The LC filter circuit having no influence on the inverter control is provided.

Description

  The present invention relates to a power conversion apparatus for a railway vehicle that converts a DC power supply voltage from a DC power supply into an alternating current and drives an AC motor to drive the railway vehicle, and relates to a ripple voltage included in the DC power supply voltage. The railcar power converter determines the presence of the railcar by suppressing the current flowing into the railcar power converter and the ripple current generated by the railcar itself and flowing out to the power supply system including the DC power supply. The present invention relates to a technique for suppressing the disturbing current applied to signal equipment and communication equipment laid in the vicinity of a track circuit or a railway and ensuring the reliability of a railway system.

  An example of the relationship between the DC power supply and the railway vehicle will be described with reference to FIG. The three-phase alternating current 31 is converted into direct current by the rectifier 32, and this voltage is applied between the overhead wire 34 and the rail 35 by the wiring 33 and the wiring 36. The train (vehicle) 20 receives a DC voltage applied between the overhead wire 34 and the rail 35 via the current collector 21 and the wheels 23 and obtains electric power for driving the vehicle 20 and an in-vehicle power source. Normally, the output of the rectifier 32 includes a ripple component that is six times the power frequency of the three-phase AC power supply 31 due to rectification.

  In addition, the fundamental wave, that is, the commercial frequency component of the three-phase alternating current 31, is included due to the unbalance of the correlation of the semiconductor and the reactor (not shown) constituting the rectifier 32. Here, the commercial frequency is a power supply frequency that is generally used, and is 50 Hz or 60 Hz in Japan, 50 Hz in Europe, and 60 Hz in the United States.

  Next, a configuration example of a railway vehicle power conversion device will be described with reference to FIG. 4 is composed of a plurality of semiconductors. The inverter 13 for converting the direct current from the current collector 21 into alternating current to drive the alternating current motor 22, the filter reactor 11, and the filter capacitor 12 is provided. The filter circuit prevents the high frequency component accompanying the switching of the inverter 13 from flowing out to the power supply system, absorbs the pulsating component contained in the input DC power supply, and supplies a stable DC voltage to the inverter.

  On the other hand, a track circuit for determining the presence or absence of a train in a specific section is installed on the ground side. The basic operation principle of the track circuit will be described with reference to FIG. 5 showing an equivalent circuit of the track circuit.

  A voltage is applied to the left and right tracks from one end of the rails 521 and 522 using the power source 51, and the voltage between the rails 521 to 522 is measured at the other end. Detect the presence or absence. When there is no train in the corresponding section (FIG. 5A), a voltage having a level substantially equal to the power supply voltage appears in the vehicle unit 53 at the detection end. When there is a train in the section (FIG. 5B), the left and right tracks 521 and 522 are short-circuited by the train wheels 61 and 62 and the wheel shaft 63, so that the voltage is applied to the vehicle detector 53 at the detection end. It does not appear.

  Based on such a phenomenon, the vehicle detector 53 determines that the train does not exist if the voltage at the detection end is equal to or higher than a predetermined threshold value, and determines that the train exists if the voltage is equal to or lower than the threshold value. At this time, in the vehicle detector 53, only the frequency component of the power source 51 is detected by the filter circuit, and the presence or absence of the vehicle is determined, thereby improving the reliability and noise resistance of the track circuit.

  Furthermore, the track circuit detects the control of the traffic light and the train position based on the vehicle detector 53, and the track circuit is a very important device for ensuring the safety of the railway. As the power supply for the track circuit, the configuration of the power supply was easy. An AC power supply has been used in many cases. Recently, with the development of power conversion technology and signal amplification technology, higher-frequency AC power supplies and modulated signals are being used.

  By the way, in the DC feeding section, the three-phase AC for obtaining the DC power source shown in FIG. 3 is also a commercial frequency. Will be. For this reason, if the input impedance to the commercial frequency of the power converter is not sufficiently high, the commercial frequency and pulsation component included in the DC voltage will cause the same component as the frequency used by the track circuit to flow on the rail, There is a possibility that the detector 53 malfunctions.

  That is, as shown in FIG. 5 (C), when the railway power converter 1 shown in FIG. 4 is used, the noise source 64 equivalently represents the noise component that the railway power converter 1 exerts on the track circuit. The high-frequency component flows as an interference power source 55 in the order of the axle 63 → the wheel 61 → the rail 521 → the vehicle detector 53 → the rail 522 → the wheel 62 → the axle 63, and the vehicle cannot be accurately detected.

  For this reason, it is necessary to make the input impedance with respect to the commercial frequency of a power converter sufficiently high. As a means for realizing this, there is a method of increasing the reactance of the filter reactor 11 shown in FIG.

  However, increasing the reactance to ensure the impedance is not an appropriate means from the viewpoint of mounting space and weight. Therefore, an attempt has been made to increase the impedance of the LC filter circuit including the filter reactor 11 by increasing the filter capacitor 12.

Japanese Patent Laid-Open No. 2006-6002

  However, there has been a problem with attempts using the above configuration. In addition to the filter function of the LC filter circuit, the filter capacitor 12 has a role as a smoothing capacitor for a three-phase inverter that generates AC power from DC power. Therefore, increasing the capacity of the filter capacitor affects the power input / output during switching of the power converter and affects the inverter characteristics.

  An object of the present invention is to provide a configuration that can increase the impedance of a filter circuit by increasing the number of filter capacitors without increasing the filter reactor and that does not affect the characteristics of the inverter.

  In order to solve the above problems, a railway vehicle power converter according to the present invention includes a plurality of semiconductor elements constituting the power converter, a gate control circuit for supplying a gate signal to the semiconductor elements, and a DC terminal of the power converter circuit. And a filter capacitor 12 for smoothing a direct current, the semiconductor element and the filter capacitor are housed in a common housing, and the filter capacitor 12 and the semiconductor element are fixed to each other, and an inverter Stabilize the characteristics.

  In the power converter, a separate filter capacitor for preventing erroneous detection of the track circuit is prepared in order to increase the capacity of the filter capacitor. An L (cable) 142 having an impedance is used for a connection portion between the separately placed filter capacitor 141 and the filter capacitor 12 in the power converter. Here, it is necessary to adjust the impedance value so that no resonance current flows between the filter capacitor 12 and the separate filter capacitor 141 in the power converter. By doing so, it becomes the structure which does not affect the power in / out at the time of switching of the power converter, and increases the LC filter circuit without affecting the inverter characteristics.

  According to the present invention, the input impedance can be increased without increasing the filter reactor. Further, by making the connection between the separately placed capacitor and the filter capacitor of the power conversion device have an impedance of 100 nH or more, the inverter control can be prevented from being affected.

FIG. 1 is a diagram illustrating the configuration of a separately placed capacitor unit in the power converter. FIG. 2 is a diagram illustrating a filter capacitor integrated power converter. FIG. 3 is a diagram for explaining the relationship between the railway vehicle power supply system and the train. FIG. 4 is a diagram for explaining the configuration of a conventional railway vehicle power converter. FIG. 5 is a diagram for explaining the relationship with the track circuit of a train.

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

  FIG. 1 shows a power conversion apparatus with a separate capacitor unit 14 that the present invention implements. FIG. 2 shows a filter capacitor integrated power converter.

  First, the main circuit configuration of the power conversion device of this embodiment will be described with reference to FIG. FIG. 2 is a circuit connection diagram showing a main circuit configuration of the power converter.

  The main circuit of FIG. 2 includes a filter capacitor 12 connected between DC terminals P and N and a three-phase inverter 13. The three-phase inverter 13 converts the input direct current into a three-phase alternating current having an arbitrary frequency and an arbitrary voltage, and outputs the three-phase alternating current to the alternating current terminals U, V, and W.

  The six semiconductor elements (PU, NU, PV, NV, PW, NW) of the three-phase inverter 13 are composed of an IGBT (Insulated Gate Bipolar Transistor) 2. Each phase IGBT 2 includes an element and a free wheel diode connected in parallel to the element. In the structural example described in this specification, each semiconductor element (PU, NU, PV, NV, PW, NW) is collectively referred to as IGBT2.

  The characteristics of the power converter described above are that the filter capacitor and the power unit are integrated to stabilize the inverter control while keeping the wiring length, filter capacitor capacity, and main circuit impedance in the power converter constant. It becomes possible.

  A separate capacitor unit 14 shown in FIG. 1 is attached using the above-described power converter. The separately placed capacitor unit 14 is a unit composed of an L (cable) 142 having an impedance of 100 nH (nanohenry) or more in order to connect the filter capacitor 141 and the filter capacitor 12 of the power converter. .

  By using the separate capacitor unit 14 described above, the impedance of the filter circuit is increased by changing the resonance point formed by the LC circuit, and the input impedance can be increased without increasing the filter reactor. Moreover, it can be set as the structure which does not affect inverter control by making the connection of a separately placed capacitor | condenser and the filter capacitor | condenser of a power converter device into the impedance of 100 nH or more.

1 Power converter 2 IGBT
11 Filter Reactor 12 Filter Capacitor 13 Inverter 14 Separate Capacitor Unit 20 Vehicle 21 Current Collector 22 AC Motor 23 Wheel 31 AC Three-Phase Power Supply 32 Rectifier 33, 36 Electric Wire 44 Overhead Wire 45 Rail 51 Track Circuit Power Supply 53 Vehicle Detector 54 Track circuit current 55 Interference power supply 61, 62 Wheel 63 Axle 64 High frequency power supply 141 Separate filter capacitor 142 Impedance L (cable)
521, 522 rail

Claims (4)

A plurality of semiconductor elements constituting a power conversion circuit;
A gate control circuit for supplying a gate signal to the semiconductor element;
In the railway vehicle power converter, the filter capacitor connected to the DC terminal of the power converter circuit and smoothing the DC current is integrated with the power converter circuit.
A power conversion apparatus for a railway vehicle, comprising a separate capacitor for preventing erroneous detection of a track circuit connected to the force conversion circuit with a predetermined impedance.   The railway vehicle power converter according to claim 1, wherein the predetermined impedance of the separately placed capacitor is ensured to be 100 nH or more.   2. The railway vehicle power converter according to claim 1, wherein the separate capacitor is installed in the same box as the case where the filter capacitor is formed integrally with the power converter circuit. A power conversion device for railway vehicles.   2. The railway vehicle power converter according to claim 1, wherein the separate capacitor is a cable, and the impedance is set to a predetermined value by connecting the filter capacitor and the power converter circuit in an integrated structure. Vehicle power conversion device.

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