JPS6126401A - Active filter unit for electric railcar - Google Patents

Abstract

PURPOSE:To reduce a ripple current of a commercial frequency band by detecting the pulsating voltage of a commercial frequency from the pulsating voltage of a filter capacitor, inverting the phase, and superposing it on the DC voltage of a main circuit. CONSTITUTION:A DC power collected by a pantograph 1 is supplied through a DC filter circuit composed by connecting a reactor 5 and a capacitor 6 an inverted L shape and an inverter 7 to an induction motor 8. A band pass filter 9 sorts the pulsating voltage of a commercial frequency from a voltage between the terminals of the capacitor 7, the phase is inverted by a transformer 11, and superposed on a DC voltage of a main circuit. On the other hand, a low frequency vibration detector 16 stops the operation of the inverter 7 when the commercial frequency band component contained in the feedback current detected by an AC unit 15 becomes the prescribed level of higher.

Description

Detailed Description of the Invention (Technical Field of the Invention) The present invention relates to an active filter device for an electric vehicle, and in particular to a method for preventing induction disturbances when operating an induction motor for driving an electric vehicle using the output of a variable voltage/variable frequency inverter. The present invention relates to an active filter device for electric vehicles that enables suppression.

[Technical background of the invention and its problems]

Figure 7 is a main circuit configuration diagram of a general electric vehicle control device when an induction motor is controlled by a variable voltage/variable frequency inverter (hereinafter referred to as VVF inverter), and the DC power collected by the pantograph 1 is , main fuse 2. Flow interrupter 3. Power is supplied to the VVVF inverter 7 through a DC filter circuit configured by connecting the high-speed breaker 4, the reactor 5, and the capacitor 6 in an inverted manner.
The VVF inverter 7 converts it into variable voltage/variable frequency three-phase alternating current to control the induction motor 18.

In an electric vehicle control device with such a configuration, 1. Inductive disturbances caused by the current controlled intermittently by the semiconductor switching element used in the VVF inverter 7, that is, inductive disturbances that occur when performing a wide range of variable frequency operation from low frequency to high frequency. A return current i containing harmonics of a frequency six times the inverter frequency flows as shown in FIG. 7, and the induction of this harmonic current causes a problem of malfunctioning of various safety equipment such as traffic lights and railroad crossings. For this reason, for example, the ripple current component included in the return current must be suppressed to 0.7 A or less in the case of commercial frequency bands of 50 and 60 Hz.

Therefore, in an electric vehicle driven by a conventional VVVF inverter-controlled induction motor, in order to reduce the harmonic components included in the return current, a capacitor is installed in series and in parallel with a reactor on the DC input side as shown in Figure 7. Reverse shape L used
A G passive filter is used. However, in order to reduce harmonic components in the commercial frequency band to below the above values with this configuration, it is necessary to considerably increase the values of the reactor and capacitor. , but on the other hand, there are restrictions on the space in which to install them.

For example, in an inverted LC passive filter device, 50Hz
To attenuate the component ripple current by 10dB, l=10
As mH, a very large value of C=6500 μF must be used.

As explained above, in the conventional inverted type LC passive filter device, in order to attenuate the harmonic components contained in the return current, especially the components below the commercial frequency band, a large-capacity glue paddle and a capacitor are required. For vehicle use, it is disadvantageous in terms of weight, space, and economy.

[Purpose of the invention]

The present invention has been made in view of the above points, and aims to reduce harmonic current contained in the return current during operation of an electric vehicle driven by an induction motor controlled by a VF inverter, particularly ripple current in the commercial frequency band. It is an object of the present invention to provide an active filter device for an electric vehicle that can further improve reliability.

[Summary of the invention]

In order to achieve the above object, the present invention inputs direct current to a variable voltage/variable frequency inverter through a direct current filter circuit in which a reactor and a capacitor are connected in reverse, and the converted alternating current is used to drive an electric vehicle. In a device that operates an induction motor for A transformer whose winding is connected in series with the reactor and whose polarity is opposite to the pulsating voltage of the capacitor, an AC current transformer with a gap that detects the return current of this transformer, and the bandpass filter that detects harmful The present invention is characterized by comprising an output overvoltage control device that selects frequency components and stops the operation of the inverter when the frequency components exceed a predetermined level.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment of the active filter device for electric vehicles of the present invention, and the same parts as the main circuit diagram of the electric vehicle control device shown in FIG. 7 are given the same reference numerals and their explanations are omitted. do.

In FIG. 1, reference numeral 9 denotes a bandpass filter (bandpass filter) for selecting a ripple voltage of a specific frequency (in this embodiment, a frequency in the commercial frequency band) from the voltage of the capacitor 6.
It is. Reference numeral 10 denotes an amplifier for amplifying the output of the bandpass filter 9, and an amplifier is used in which there is no phase difference between the input and output. Reference numeral 11 denotes a transformer, the secondary winding of which is connected to the output side of the amplifier 10, the secondary winding of which is connected in series with the connection point between the capacitor 6 and the VVVF inverter 7, that is, in series with the accelerator 5; This is a transformer connected so that an output with a polarity opposite to that of the ripple voltage at a specific frequency of 6 is output. 12 is an input overvoltage suppressing device connected to the input side of the band pass filter 9 to suppress the application of overvoltage; 13 is connected to the output side of the amplifier 10 to suppress the application of overvoltage from the transformer 11; output overvoltage suppressor, 14
is a control power supply 14 that supplies power to the input overvoltage suppression device'' 12 and the output overvoltage suppression device 13, respectively.

15 is a gapped AC current transformer that detects the return current of the VVVF inverter; 16 is a gapped AC current transformer that selects a specific frequency component from the output of the gapped AC current transformer 15, and when this exceeds a permissible value, the high speed This is a low frequency vibration detector that outputs a forced trip signal H3trip to the circuit breaker 4.

FIG. 2 shows an example of a specific circuit of the low-frequency vibration detector 16, which includes a bandpass filter 17 for selecting specific frequency band components from the output of the gapped AC current transformer 15, and Output of pass filter 17 and rail disturbance current l! It is composed of a comparator 18 that compares the semi-permissible value Ir with the semi-permissible value Ir.

The operation of the active filter device for electric vehicles having such a configuration will be described below.

First, pantograph 1. Main fuse 2. Flow interrupter 3.
High speed breaker4. Reactor 5. The DC voltage of the main circuit composed of the capacitor 6 and the inverter 7, that is, the voltage between the terminals of the capacitor 6, is input to the bandpass filter 9. This bandpass filter 9 selects the ripple voltage in the commercial frequency band from among the ripple voltages included in the DC voltage, and the phase difference of this ripple voltage between input and output becomes almost zero, and ripple voltages at other frequencies are attenuated. do.

FIGS. 3(a) and 3(b) are for explaining this, and show the relationship between the ripple voltage in the commercial frequency band included in the DC voltage of Ichimi-no-O and the output voltage of the transformer 11. still,
FIG. 4 (a>(b) is a diagram showing the relationship between frequency and phase and the relationship between frequency and amplitude of the bandpass filter 9.

Next, the output of the band-pass filter 9 is input to the amplifier 10, and after amplifying the ripple voltage in the commercial frequency band selected by the band-pass filter 9, it is output to the transformer 11.

Here, it is desirable that the phase difference between the input and output of the amplifier 10 is almost zero, but a certain degree of correction can be made by changing the circuit constants of the bandpass filter 9 to reduce the phase difference to zero including the bandpass filter 9. It is possible to

The transformer 11 inverts the phase of the output from the amplifier 10 and superimposes it on the DC voltage of the main circuit. For this reason, the ripple voltage in the commercial frequency band is canceled out by the output voltage of the transformer 11, and the ripple current included in the return current can be reduced.

On the other hand, input overvoltage suppression device 12 and output overvoltage suppression device 1
3 efficiently absorbs the overvoltage using an overvoltage absorbing capacitor and an external control power supply 14 in order to protect the amplifier 10 from overvoltage when the main circuit starts up or during a transient phenomenon such as an accident.

Next, a gapped AC current transformer 15, a low frequency vibration detector 1
The backup circuit of the active filter device for electric vehicles constituted by 6, that is, the function for immediately stopping the operation of the VVVF inverter 7 when the function of this device is degraded or stopped for some reason will be explained.

Only the AC ripple component Ir1p of the return current of the main circuit is detected by the gapped AC current transformer 15 and output to the low frequency vibration detector 16. and low frequency vibration detector 16
Since the bandpass filter 17 in the filter is configured to have the frequency characteristic shown in FIG. . The comparator 18 momentarily compares the rail disturbance current reference allowable value 1r set externally in advance and the output 1com of the bandpass filter 17, and if the 1cOIn exceeds Ir, it immediately forcibly trips the high-speed breaker 4. Then, a signal HB trip for stopping the operation of the VVVF inverter 7 is output. The operation of this comparator 18 is summarized in FIG. 6, where (a) shows the ripple current 1 com of the commercial frequency band component.
, (b) shows the rail disturbance current reference allowable value 1r.

〔Effect of the invention〕

According to the present invention described above, direct current is input to a variable voltage/variable frequency inverter via a direct current filter circuit in which a reactor and a capacitor are connected in reverse, and the converted alternating current is used to drive an electric vehicle. In a device that operates an induction motor, a bandpass filter that detects the pulsating voltage of the capacitor and outputs a pulsating voltage of a specific frequency, and a primary winding connected to the output side of this bandpass filter,
a transformer whose secondary winding is connected in a polarity opposite to the pulsating voltage of the capacitor connected in series with the reactor; an AC current transformer with a gap for detecting the return current of the transformer; It is equipped with an output overvoltage control device that uses a bandpass filter to screen out harmful frequency components and stops the operation of the inverter when the frequency components exceed a predetermined level, so that the inverter is driven by an induction motor controlled by a VVVF inverter. It is an object of the present invention to provide an active filter device for an electric vehicle that can reduce harmonic current contained in the return current during operation of an electric vehicle, particularly ripple current in the commercial frequency band, and further improve reliability. can.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram showing an embodiment of an active filter device for electric vehicles according to the present invention, FIG. 2 is a diagram showing the relationship between the ripple voltage in the commercial frequency band included in the voltage and the transformer output voltage, and FIG. Figures (a>(b) are diagrams showing the relationship between frequency and phase and the relationship between frequency and amplitude of the bandpass filter of the same example, Figure 5 is a diagram showing the frequency characteristics of the bandpass filter of the same example, Figure 6 is a diagram showing the ripple current of the commercial frequency band component and the rail disturbance current reference allowable value to explain the operation of the comparator of the same embodiment. It is a main circuit configuration diagram of a general electric vehicle control device when controlling. 1... Pantograph, 2... Main fuse, 3...
... Current breaker, 4... High speed breaker, 5... Reactor, 6... Capacitor, 7... Variable voltage/variable frequency inverter, 8... Induction motor, 9... Band Pass filter, 11...Transformer, 12...Input overvoltage suppression device, 13...Output overvoltage suppression device, 14.
... Control power supply, 15 ... AC current transformer with gap, 16
...Low frequency vibration detector, 17...Band pass filter, 18...Comparator. Applicant's representative Patent attorney Takehiko Suzue Figure 1 Figure 2 r HBtr1p accumulated U force) Figure 3 Figure 4 r@combined [H2] Figure 5 Figure 7 Procedural amendment (method) % formula % 1 , Indication of the case Japanese Patent Application No. 147379/1982 2 Name of the invention Active filter device for electric vehicles 3, Person making the amendment Relationship to the case Patent applicant (307) Toshiba Corporation 11, Agent October 30, 1988 6th Amendment] Specification 7, Contents of amendment (1) Riggle voltage in the commercial frequency band and transformer output voltage included in the DC voltage of the circuit described in December 1st line to negative line 4 of the specification "A diagram showing the relationship between," corrected. (2) "A diagram showing the relationship between phase and frequency and amplitude with respect to Figure 4 (a)" written in lines 4 to 6 of No. 12 No. A diagram showing the relationship between frequency and phase and the relationship between frequency and amplitude of an example bandpass filter.''

Claims (1)

[Claims] Direct current is input to a variable voltage/variable frequency inverter through a direct current filter circuit in which a reactor and a capacitor are connected in an inverted L shape, and the converted alternating current is used to drive an induction motor for driving an electric vehicle. a bandpass filter that detects the pulsating voltage of the capacitor and outputs the pulsating voltage of a specific frequency; and the capacitor, the primary winding of which is connected to the output side of the bandpass filter, and the secondary winding of which is connected in series with the reactor. A transformer connected with a polarity opposite to the pulsating voltage of An active filter device for an electric vehicle, comprising: an output overvoltage control device that stops operation of the inverter when the level exceeds the output overvoltage level.