JP2009182115A - Transformer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transformer capable of suppressing the occurrence of an induction obstacle with a compact and simple configuration. <P>SOLUTION: The transformer 20 includes: a primary winding 2a connected to a primary side PL1 supplied with electric power from a current collecting device; secondary side windings 2b and 2e connected to secondary side PL2 and SL2, and PL3 and SL3; and auxiliary windings 2c and 2f connected to the secondary side windings 2b and 2e in parallel. The primary side winding 2a is wound around a leg iron center portion of an iron core 22, and the secondary side windings 2b and 2e are wound on both sides of the primary winding 2a of the iron core 22 in parallel to the primary winding 2a. Further, the auxiliary windings 2c and 2f are wound on the opposite side from the primary winding 2a with the secondary side windings 2b and 2e interposed therebetween. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transformer, and more particularly to a transformer mounted on an electric vehicle.

  In general, railcars use signals in various frequency bands, so it is necessary to consider not causing inductive interference in various signals due to harmonic noise generated from the control equipment installed in the vehicle. There is. This inductive failure is largely caused by a return current flowing out from the ground line via a transformer mounted on the vehicle.

  As one method for suppressing the occurrence of such an inductive failure, Japanese Patent Application Laid-Open No. 2004-22754 (Patent Document 1) discloses a technique for suppressing signals of various frequency bands by suppressing harmonic currents flowing out from the ground line. A transformer for a vehicle that takes measures against inductive failure is disclosed. According to this, the transformer for the vehicle winds the high-voltage winding and the low-voltage winding around the iron core, arranges the electrostatic shielding plate between the two windings, and stores it in the tank. The tank is configured to be grounded through the vehicle body. In such a configuration, at least the iron core lead wire connected to the iron core is insulated from the tank and led out of the tank, and the iron core impedance is connected between the iron core lead wire and the vehicle body outside the tank.

The vehicle transformer disclosed in Patent Document 1 suppresses the harmonic current of the return current flowing out from the ground line by connecting the impedance between the line drawn to the outside of the tank and the vehicle body in this way. can do. As a result, it is possible to take countermeasures against inductive interference for signals in various frequency bands used in the vehicle.
JP 2004-22754 A

In railway vehicles, it is necessary to reduce the size and weight of the vehicle body and accessory equipment.
However, the vehicular transformer disclosed in Patent Document 1 requires a space for installing the impedance for the iron core outside the tank.

  That is, in the vehicle transformer disclosed in Patent Document 1, the impedance for the iron core, the impedance for electrostatic shielding, and the impedance for the tank are installed outside the tank. Thus, the value of each impedance is determined so that the inductive disturbance is minimized. Therefore, by installing a combination of a plurality of impedances, it is possible to realize an impedance suitable for countermeasures against inductive disturbances, while increasing the number of underfloor equipment for vehicles.

  Therefore, the present invention has been made to solve such a problem, and an object of the present invention is to provide a transformer capable of suppressing the occurrence of inductive failure with a small and simple configuration.

  According to one aspect of the present invention, the transformer is wound in parallel with the primary side winding on the same leg as the primary side winding of the iron core, the primary side winding wound around the iron core. A secondary winding wound on the same leg and an auxiliary winding that is wound on the opposite side of the primary winding across the secondary winding and connected in parallel to the secondary winding. Prepare.

  According to the present invention, it is possible to suppress the occurrence of an induction failure with a small and simple device configuration.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same reference numerals indicate the same or corresponding parts.

  FIG. 1 is a schematic configuration diagram of a drive control device for an electric vehicle to which a transformer according to an embodiment of the present invention is applied.

  Referring to FIG. 1, a drive control device for an electric vehicle includes a current collector 10 that collects current from an AC overhead line 1, a transformer 20, a power converter 30 (a converter 31 and an inverter 32), and an electric motor (motor). 40 and a power conversion control device (not shown) for controlling the power conversion device 30.

  In this electric vehicle drive control device, the power collected by the current collector 10 from the AC overhead line 1 is stepped down by the transformer 20 and supplied to the power converter 30. And the single phase alternating current power supplied from the transformer 20 in the power converter device 30 is converted into three phase alternating current power, and the motor 40 is driven with this three phase alternating current power.

  The transformer 20 includes a primary winding 2a connected to PL1 connected to the current collector 10, a SL1 connected to ground, and a secondary winding 2b connected to PL2 and SL2 connected to the power converter 30. And secondary winding 2e connected to PL3 and SL3 connected to power converter 30, auxiliary winding 2c, primary winding 2a, secondary winding 2b and auxiliary winding 2c are wound. An iron core 2d.

  When a voltage V1 having a predetermined rated frequency (for example, 50 to 60 Hz) is input to the primary winding 2a from the current collector 10 through PL1 and PL2, a current flows through the primary winding 2a. When a current flows through the primary winding 2a, a magnetic field is generated around the primary winding, thereby generating a voltage V2 in the secondary winding 2b. At this time, the relationship between the voltage V2 generated in the secondary winding 2b and the voltage V1 generated in the primary winding 2a is determined by the ratio of the number of windings N1 and N2, as shown in the following equation.

V2 = V1 · (N2 / N1) (1)
In such a transformer 20, the specification value of the leakage reactance is determined by the performance required by the converter 31. Generally, in the power conversion device 30 including the PWM converter 31 and the VVVF inverter 32, a high short-circuit impedance value of about 20%. Is required.

  Specifically, in the transformer 20, when all the magnetic fluxes are linked to both the primary side winding 2a and the secondary side winding 2b, there is no leakage reactance. Designed for proper leakage reactance.

  Power conversion device 30 is connected in parallel to secondary sides PL2, SL2, PL3, and SL3, and converts single-phase AC power and three-phase AC power to each other. That is, the power converter 30 converts the single-phase AC power supplied from the transformer 20 via the secondary side PL2, SL2, PL3, SL3 into a three-phase AC in response to a switching command from a power conversion controller (not shown). It is converted into electric power and supplied to the motor 40. Further, the three-phase AC power generated by the motor 40 is converted into single-phase AC power and supplied to the transformer 20 as regenerative power.

  At this time, the switching operation of the converter 31 is performed at a switching frequency higher than the rated frequency (50 to 60 Hz) of the transformer 20 described above. Therefore, the converter 31 generates a harmonic current having a frequency (several kHz) higher than the rated frequency of the transformer 20. The generated harmonic current noise may cause inductive failure in various signals due to a return current flowing out from the ground line SL1 through the transformer 20. Therefore, it can be seen that as a countermeasure against inductive failure, it is sufficient to increase the short-circuit impedance in the frequency band of the harmonic current. On the other hand, at the rated frequency, it is necessary to maintain a short-circuit impedance that causes an appropriate leakage reactance.

  Therefore, as shown in FIG. 1, transformer 20 according to the present embodiment has a configuration in which auxiliary winding 2c is connected in parallel to secondary winding 2b. In such a configuration, the auxiliary winding 2c maintains the short-circuit impedance of the transformer 20 at a predetermined impedance value at the rated frequency, while having a high impedance in the frequency band of the harmonic component, as described below. It shall arrange so that it may become a value.

  FIG. 2 is a perspective view showing the contents of the outer iron type transformer. Referring to FIG. 2, the coil 2 of the transformer is wound around the iron core 22, and the iron core 22 is provided so as to be located outside the coil 2.

  FIG. 3 is a cross-sectional view of the transformer according to the present embodiment, and is a cross-sectional view corresponding to a cross section taken along line AA in FIG.

  The primary winding 2 a is wound around the center of the leg iron of the iron core 22. The secondary windings 2b and 2e are wound on both sides of the primary winding 2a of the iron core 22 in parallel with the primary winding 2a.

  Further, the auxiliary winding 2c is wound on the opposite side of the primary winding 2a with the secondary winding 2b interposed therebetween. And the terminal of the auxiliary | assistant coil | winding 2c is withdraw | derived to the exterior of the iron core 2d, and is connected to the secondary side transmission / distribution electric wires PL2 and SL2. Thereby, the auxiliary winding 2c is connected in parallel with the secondary winding 2b.

  The auxiliary winding 2c has the same number of windings (= N2) as the secondary winding 2b. This is to maintain the relationship between the voltage V2 generated in the secondary winding 2b and the voltage V1 generated in the primary winding 2a. Alternatively, the auxiliary winding 2f may be connected to the secondary winding 2e.

  The transformer according to the present embodiment is configured such that the auxiliary winding 2c is wound on the opposite side of the primary winding 2a with the secondary winding 2b interposed therebetween, so that the primary winding 2a and It is possible to suppress the auxiliary winding 2c from affecting the magnetic space formed between the secondary winding 2b. Thereby, even if the auxiliary winding 2c is wound, the leakage magnetic flux flowing through the magnetic space does not change, so that the leakage reactance of the transformer 20 caused by the leakage magnetic flux can be maintained. By maintaining the leakage reactance, the secondary winding 2b is supplied with substantially the same amount of current as that in the state where the auxiliary winding 2c is not wound. The flowing current can be kept small.

  As described above, since the current flowing through the auxiliary winding 2c is suppressed to be small, it is possible to configure the auxiliary winding 2c with a conductor having a small cross-sectional area. As a result, since the auxiliary winding 2c can be configured with a thin and light weight, it is possible to suppress an increase in the size and weight of the transformer 20 by newly winding the auxiliary winding 2c. This can reduce the size of the fitting as compared with a system in which an external impedance is connected under the floor of the vehicle.

  Furthermore, according to transformer 20 according to the present embodiment, the short-circuit impedance at the rated frequency of transformer 20 can be maintained at a substantially constant value by winding auxiliary winding 2c.

  That is, in the rated frequency region of the transformer 20, the leakage reactance generated by the leakage magnetic flux generated in the magnetic space between the primary side winding 2a and the secondary side winding 2b is sufficiently reduced by the winding resistance of the transformer 20. Since it can be considered large, the change in winding resistance due to the winding of the auxiliary winding 2c can be almost ignored. Therefore, the short-circuit impedance of the transformer 20 at the rated frequency is substantially equal to the leakage reactance. Here, as described above, since the leakage reactance is maintained substantially constant by winding the auxiliary winding 2c, the short-circuit impedance at the rated frequency is not affected by the auxiliary winding 2c. An appropriate impedance value is maintained.

  On the other hand, the impedance in the frequency band of the harmonic current is changed by the change in capacitance and resistance due to the addition of the auxiliary winding to the secondary winding.

  FIG. 4 shows the high-frequency impedance characteristics of the transformer 20. In FIG. 4, the horizontal axis indicates the frequency, and the vertical axis indicates the short-circuit impedance. Note that the line LN1 in the figure is a short-circuit impedance characteristic of the transformer 20 when the auxiliary winding 2c is wound. For comparison, a line LN2 in the figure shows the short-circuit impedance characteristic of the transformer 20 when the auxiliary winding 2c is not wound. Each impedance characteristic is obtained by simulating the short-circuit impedance of the transformer 20 in a frequency band (several kHz) higher than the rated frequency (50 to 60 Hz) of the transformer 20 using a predetermined circuit simulation. It is a thing.

  Referring to FIG. 4, the impedance characteristics of the harmonics of transformer 20 tend to increase or decrease depending on the frequency range. In this example, there is a characteristic that the frequency falls between 90 and 100 kHz (e.g., corresponding to the region RGN in the figure). Here, comparing the line LN1 and the line LN2 in the figure, it can be seen that the frequency at which the impedance value of the line LN1 is lower than that of the line LN2 is shifted to the low frequency side. According to this, by winding the auxiliary winding 2c, the frequency at which the harmonic impedance is lowered can be moved away from the frequency band in which the inductive disturbance is a problem. Therefore, the occurrence of inductive failure can be suppressed by optimizing the winding resistance of the auxiliary winding 2c so as to increase the impedance in the harmonic band and shifting the resonance point of the transformer 20.

  As described above, according to the embodiment of the present invention, it is possible to increase the impedance of the harmonic band without adding an external device such as an iron core impedance or a bypass filter to the transformer. As a result, it is not necessary to add an external device as a countermeasure against inductive failure, and thus the drive control device for the electric vehicle can be reduced in size and weight.

  Furthermore, since the auxiliary winding has the same winding structure as the primary side winding and the secondary side winding, it can be easily manufactured in the existing manufacturing process without adding a special manufacturing process. Can do. Further, since the auxiliary winding can be made thinner than the secondary winding, it is not necessary to change the design of the transformer itself, and it is possible to promote the reduction in size and weight of the drive control device for the electric vehicle.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram of the drive control apparatus of the electric vehicle to which the transformer according to embodiment of this invention is applied. It is a perspective view which shows an outer iron type transformer. FIG. 3 is a cross-sectional view corresponding to a cross section taken along line AA of the transformer of FIG. 2. This is the high frequency impedance characteristic of the transformer.

Explanation of symbols

  1 AC overhead wire, 2a Primary side winding, 2b, 2e Secondary side winding, 2c, 2f Auxiliary winding, 2d Iron core, 10 Current collector, 20 Transformer, 22 Iron core, 24 Relay, 30 Power converter, 31 converter, 32 inverter, 40 motor.

Claims (2)

Iron core,
A primary winding wound around the iron core;
The secondary side winding wound side by side with the primary side winding on the same leg as the primary side winding of the iron core,
A transformer comprising: the same leg, and an auxiliary winding that is wound on the opposite side of the primary winding with the secondary winding interposed therebetween and connected in parallel to the secondary winding.   The transformer according to claim 1, wherein the auxiliary winding has the same number of windings as the secondary winding.

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