JPS60236844A - Voltage varying system for electric vehicle - Google Patents

Abstract

PURPOSE:To suppress a higher harmonic current of the input current of the conventional vehicle-loaded VVVF type three phase invertor and a higher harmonic current of a substation rectification ripple component and prevent other circuits from being subjected to an induction trouble by connecting a serial reactor to a substation rectifier in series in a DC substation. CONSTITUTION:When a serial reactor Ls is connected in series to the substation rectifier REC of a DC substation, the ripple component IRN of the substation rectification becomes smaller by an amount in which the inductance of the serial reactor is added. Therefore, this inductance is selected as appropriate, to make the ripple component less than an allowable value. To suppress the higher harmonic current of the input power source IINV of a vehicle-loaded VVVF type three phase invertor INV, inductance consisting of an attenuation characteristic of an input filter (a main filter reactor Lf and a main filter capacitor Cf), is defined as a main filter reactor Lf, making the serial reactor Ls of the DC substation take charge of inductance above said inductance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to (a) the removal of inductive disturbances in substation systems for electric vehicles, particularly in substation systems for DC electric railways.

[Prior art]

In recent years, in the propulsion system of electric cars of DC electric railways,
BACKGROUND ART Electric vehicles have been put into practical use that use a squirrel-cage three-phase induction motor as the main motor and perform speed control with a high-frequency modulated variable frequency variable voltage (hereinafter referred to as VVVF) type J-phase inverter. In FIG. 1, the system is shown. In the diagram, S is a DC substation, and FEC is a substation rectifier installed in this DC substation S. L is a direct current M and an overhead wire through which a current from S flows, and LJ is the overhead wire inductance of this overhead wire. Also, T is an electric car, and Pa
n is a pantograph that takes in current from the overhead line, Lf is a filter reactor, Cfkt is a main filter capacitor,
IM/ and IMJ are squirrel-cage three-phase induction motors that are the main motors, and INV converts DC to J-phase AC and drives and controls the J-phase induction motors IM/ and IMJ.
P' type 3-phase inverter, W is the wheel of electric vehicle T, and R is
is a rail that serves as a return line to the DC substation S. In addition, Fig. 1 shows the input-output waveforms of the VVVF type three-phase inverter INV in the electric car T shown in Fig. 7, and (a)
is the input current, and (b) is the output voltage.

And (C) shows the output current, respectively.

As shown in FIG. 2(a), the input current IINV of the VVVF type three-phase inverter INV is intermittent, and its frequency component changes depending on the speed of the electric vehicle T. If this frequency component exceeds the permissible amount in a specific frequency range, there is a risk that the track relay (not shown) may malfunction.
This prevents the exchange generated from the VVVF type three-phase inverter INV from flowing to the overhead wire.

Now, in Fig. 1, the harmonic current flowing in the overhead wires is the substation rectification ripple component IRN flowing out from the substation rectifier RgC, which is generally composed of a three-phase bridge rectifier provided in the DC substation S, and the above-mentioned substation rectification ripple component IRN. vvvF type 3
There are harmonic currents of the input current IINV of the phase inverter, which flow in a superimposed manner through the overhead wire and also into the rail R as the return wire. In particular, when the high-order frequencies of both harmonic currents match, the number of one combined harmonic current increases rapidly. These harmonic currents and composite harmonic currents may cause induction disturbances in commercial frequency track circuits, inductive radio circuits, telephone circuits, ATC track circuits, and the like. In the conventional substation system, the input current IXNV of the on-board VVVF type 3-phase inverter (-INV) was determined by the on-board input filter, but the substation rectifier RFC installed at the DC substation S As for the rectification ripple component InH, it was not completely reduced by the on-vehicle input filter, but there was a risk of causing an induction disturbance to other circuits.

[Summary of the invention]

This invention was made to improve the above-mentioned drawbacks by connecting a series reactor in series with a substation rectifier in a DC substation.

In addition to suppressing the harmonic current of the input current of the conventional VVVF type 3-phase inverter on the vehicle, we also suppress the harmonic current of the substation rectification ripple component in the DC substation, which prevents induction disturbances to other circuits. This paper proposes a substation system for electric vehicles that eliminates the need for electric vehicles.

[Embodiments of the invention]

FIG. 3 shows an embodiment of the DC substation of the electric vehicle substation system according to the present invention, in which a series reactor is installed in series on the rail R side of the substation rectifier RgC of the DC quality 'Iff and station S. It is being Note that electric cars are the same, so we have omitted them.

In order to eliminate induction disturbances, harmonic cylinders and currents (VVVF type 3
Input current of phase inverter INV (harmonic component of NV)
It is necessary to simultaneously suppress the harmonic current caused by the substation rectifier ripple component IRN generated by the substation rectifier REC. The substation rectification ripple component IRN is expressed by the following equation (1).

However, En: harmonic voltage of the rectified voltage considering the weight angle, n: harmonic order, If: inductance value of the main filter reactor Lf, ! JLI4 = Inductance value of overhead wire inductance L (1>) To reduce the substation rectification ripple component IRN, from equation (1), inductance value J- of main filter reactor Lf
It can be seen that either f should be increased or the inductance Ll of the overhead wire inductance L# should be increased. However, the inductance value i of the main filter reactor Lf mounted on the vehicle
Increasing f is not realistic because there is a main f, and
This results in an increase in power consumption due to an increase in vehicle weight.

Therefore, in this invention, a series reactor LS is installed on the DC transformer, transformer S, and rectifier REC rule R side. If the inductance value of this series reactor L8 is 1 g, the equation (/1) can be expressed as the following equation (c).

dπnf (Jf + J-t + J8) As is clear from equation (2), the substation rectification ripple component 1 is reduced by the addition of the inductance 7.8 of the series reactor L8 connected in series to the substation rectifier REC. . Since the inductance values J and s can be freely selected, it is possible to reduce the substation rectification ripple component IRN to a permissible value or less. Further, the harmonic current of the input power source IINV of the VVVF type three-phase inverter NY on the vehicle is suppressed as follows. That is, the input filter (main filter reactor Lf and main filter capacitor Cf)
The damping characteristic, that is, the resonant frequency fr, is expressed by the following formula (3)%
Formula % However, J-f: inductance value of main filter reactor Lf, cf: capacitance value of main filter capacitor Cf, harmonic current in a specific frequency range f, from the perspective of preventing inductive disturbances to track relays (not shown). is limited to within a certain tolerance value. Also.

The attenuation rate is expressed by the following equation (4=).

Therefore, the inductance determined from equations (3) and (4I) is mounted on the vehicle as the main filter reactor Lf, and any inductance beyond this is received by the actor L8 in the I column of the DC substation S.

Incidentally, as shown in Fig. 1, the same effect can be obtained even if the substation rectifier of the DC substation S is constituted by a thyristor bridge °rHY.

〔Effect of the invention〕

As mentioned above, the rectified ripple component 111N of the substation and the harmonic current of the input current HTV of the VVVF type three-phase inverter flow in the overhead wires of a DC electric railway in a superimposed manner, and these can cause inductive disturbances to other circuits. give. Furthermore, when the high-order frequency numbers of both of them match, the combined harmonic current increases rapidly, which also causes an induction disturbance. Therefore, in this invention, the conventional method is used.

At the same time, by connecting a series reactor in series with the substation rectifier of the DC substation, the substation rectification ripple component can be increased. It was reduced to width. As a result, the single composite harmonic current can also be suppressed to a permissible value or less, and an effect can be obtained in that induction interference to other circuits can be eliminated. In addition, even when a multi-set electric car becomes a substation load, by increasing the inductance value of the series reactor, the composite harmonics flowing to the overhead wire can be suppressed to within the allowable range. This is much more economical compared to the case where a main filter reactor is mounted on all vehicles, and in this case, it is also possible to achieve the effect of saving JPY and energy by reducing the weight of the vehicle. Furthermore, the single eave reactor also has the effect of suppressing accidental current caused by, for example, destruction of the thyristor of the V V V F type J-phase inverter on the vehicle.

[Brief explanation of drawings]

Figure 1 is a schematic diagram of a conventional substation system for electric vehicles, Figure 2 is an input/output waveform diagram of a VVVF type three-phase inverter, and Figure 3
This figure is a schematic diagram showing one embodiment of a DC substation of an electric vehicle substation system according to the present invention, and FIG. 9 is a schematic diagram showing another embodiment of the present invention. S: DC substation, RECφ, substation rectifier, Lφ, overhead line, Re-fist overhead line inductance, T: Electric car, P
an...Pantograph, Lf...Main filter reactor, Cf11II main filter capacitor. IM/ and IMJ: 3-phase induction motor, INV: High-frequency modulation variable frequency variable voltage 3-phase inductor (VVV
F type 3-phase inverter), W.-Wheel, R..Rail, L
8...Series reactor, 'I'HY...Substation rectifier (thyristor bridge). In each figure, the same reference numerals indicate the same or corresponding parts. 2nd figure Death 31 q Death 4th figure S Procedural amendment (voluntary) Showa 5CP September. Mr. Commissioner of the Japan Patent Office 1, Indication of the case 1964 Patent Application No. Deco! ! 9 No. 2, Title of the invention: Electrical substation system for one-shot use C) Amend the statement "from harmonic current" on page 3, line 16 of the same document to "from harmonic current." C) Amend the statement "from harmonic current" on page 3, line 16 of the same document as [1- Correct to within. (41, page 6, prefecture J line, "ve)" is corrected to rLtJ.

Claims (1)

[Claims] 1] (1) A three-phase induction motor is used as the main motor, and a variable wave number variable voltage type three-phase inverter is used as the main motor and 1. A substation system for an electric car, characterized in that a series reactor is connected in series with a substation rectifier at a DC substation that supplies power to the electric car that controls the speed of the three-phase induction motor. (λ) The substation system for an electric vehicle according to claim 1, wherein the substation rectifier is constituted by a thyristor bridge.