JPH05199607A - Power converter for electric vehicle - Google Patents

Abstract

PURPOSE:To prolong the operation sustaining time of inverter through a capacitor having low withstand voltage upon contact loss of pantograph and to protect elements positively against short circuit fault of inverter by ON/OFF controlling the voltage across an external filter capacitor bank which is interruptible from the inverter. CONSTITUTION:Trolley voltage detected through a voltage detecting element 32 is compared with a reference value and a gate drive circuit 34 performs switching control of a GTO thyristor 16 to charge an external filter capacitor bank 14 with a constant voltage lower than the rated voltage of a trolley 1. When a voltage detected through the voltage detecting element 32 drops below a set level, a rectifying element 15 is turned ON to feed power to an inverter circuit 7. Upon occurrence of short circuit fault between upper and lower arms of the inverter circuit 7, an abnormal quick discharge detecting circuit 23 and a gate drive circuit 24 interrupt the operation of a GTO thyristor 20. Consequently, the external filter capacitor bank can be constituted of capacitors having low capacity and low withstand voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle which receives a DC power supply from an overhead line or a third rail, and continues the inverter circuit even when the current supply is temporarily stopped due to the disconnection of the pantograph. The present invention relates to a power conversion device for an electric vehicle that can be operated and can continue to supply power to a load.

[0002]

2. Description of the Related Art In an electric vehicle which receives a DC power supply from a DC overhead wire or a third rail, it has been conventionally used as a power converter provided for supplying power to various loads such as an air conditioner and a lighting device. Generally, an inverter circuit is widely used.

A conventional electric power converter for an electric vehicle using an inverter circuit has a structure as shown in FIG. 7, in which DC power flowing through an overhead wire or a third rail 1 is collected by a pantograph 2 and a unit switch 3 is connected. Through which the filter capacitor 6 is charged via the DC filter reactor 4 and the GTO circuit breaker 5, and DC power is supplied to the inverter circuit 7 connected in parallel with the filter capacitor 6. A voltage detector 8 is connected in parallel with the filter capacitor 6 so that the voltage of the filter capacitor 6 is detected. Further, the charging resistor 9 provided in parallel with the GTO circuit breaker 5 is for charging the filter capacitor 6 at the time of starting, and is short-circuited by the GTO circuit breaker 5 after charging.

The inverter circuit 7 is formed of three phases, and each arm is formed by arranging switching elements 71 to 76 such as IGBT or GTO as shown in FIG.

Further, between the filter capacitor 6 and the inverter circuit 7, when any of the switching elements 71 to 76 in the inverter circuit is broken and the upper and lower arms are short-circuited, the discharge current from the filter capacitor 6 is detected. However, a current detector 10 is arranged to turn off the GTO circuit breaker 5 to cut off the unit switch 3 and prevent current from flowing from the overhead wire or the third rail 1.

A transformer 12 is connected to the output side of the inverter circuit 7 via an AC filter 11, and the output of the transformer 12 is supplied to various loads of the electric vehicle.

[0007] In such a conventional electric vehicle power converter, for a traveling electric vehicle, particularly when there is only one pantograph 2, the pantograph 2 and the overhead line or the third rail during traveling. When the disconnection phenomenon that 1 is separated occurs, the supply of DC power to the inverter circuit 7 is temporarily cut off. Although this derailment time differs depending on the line segment, in the conventional electric vehicle power converter shown in FIG. 7, the operation duration of the inverter circuit 7 at the time of derailment is generally several ms to several tens ms. However, it is desirable that this operation duration can ideally be extended until the disconnection is resolved. Therefore, in order to extend the operation continuation time of the inverter circuit at the time of disconnection, the output power is conventionally reduced, or as shown in FIG. It was additionally installed to cope with the voltage drop at the time of disconnection.

However, when the filter capacitor bank 13 is additionally installed externally as described above, there are the following problems.

Now, assuming that the input current of the inverter circuit 7 is i, i = capacity of inverter circuit × power factor / (efficiency × DC input voltage) (1) iΔt = CΔV (2)

In the case of an electric vehicle, the overhead wire or the third rail 1 which is a power supply source fluctuates by ± 50% or more of the rating. Therefore, when configuring a filter capacitor, the rating is +50
The withstand voltage of more than% is required for the capacitor. For example, when the overhead wire voltage is 1500 V and the filter capacitor is configured by a capacitor of 400 V-3300 μF,
Considering the margin, it becomes 8S to 9S (S means series connection).

Therefore, in the electric power converter for an electric vehicle shown in FIG. 8, assuming that a disconnection of 60 ms occurs at a capacity of 200 kVA at DC 1500 V as shown in FIG. 9, a power factor of 0.85 and an efficiency of 0.9 (general) The value of the capacitor capacity required for the capacitor bank 13 is i = 200 × 10 ³ VA × 0.85 / from the equations (1) and (2) and the graph of FIG. (0.9 × 1500V) = about 126A 126A × 60 ms = C × (1500V-900V) Therefore, C = about 12600 μF. It should be noted that FIG. 9 shows the movement of the inverter input voltage at the time of disconnection under the condition that the input of the inverter circuit 7 is 900V DC and the low voltage is detected to stop the inverter circuit.

Therefore, the filter capacitor 6 is usually
Since a 9S9P (P means parallel number) configuration is used, the external filter capacitor bank 13 requires a capacitor bank composed of a huge number of capacitors of 9S25P (9167 μF, 225). there were.

By the way, in order to extend the operation duration of the inverter circuit when the pantograph is disconnected by using such an external filter capacitor bank, an external filter capacitor bank composed of a large number of capacitors as described above must be used. However, if an external filter capacitor bank with such a large capacity is used, the large current charged in the external filter capacitor bank will be rapidly discharged when a short circuit occurs in the arm of the inverter circuit. Therefore, there is a possibility that the switching element of the inverter circuit may be destroyed.

For example, in the conventional power converter of FIG. 8, when the switching element 72 is destroyed while the switching elements 71 and 76 of the inverter circuit 7 are in the ON state, the switching elements 71 and 72 are short-circuited. It becomes a state. In this case, in the device without the external filter capacitor bank 13 as shown in FIG. 7, the DC current from the overhead wire or the third rail 1 and the discharge current from the filter capacitor 6 try to flow into the inverter circuit 7. If the current detector 8 detects this current value and turns off the GTO circuit breaker 5 and cuts off the unit switch 3, the direct current from the overhead wire or the third rail 1 is cut off, and the discharge from the filter capacitor 6 is caused. Only current flows through the inverter circuit 7, and the degree of damage to the switching element can be small.

However, in the power conversion device having the external filter capacitor bank 13 as shown in FIG. 8, even if the GTO circuit breaker 5 is turned off and the unit switch 3 is cut off, the external filter capacitor bank 13 is overloaded. Since a current is emitted, the switching element may be destroyed in some cases, and there is a problem that parts around the element may be damaged.

[0016]

As described above, in the conventional electric vehicle power conversion device, in order to extend the operation duration of the inverter circuit when the line is disconnected, a huge amount of the capacitor is used with respect to the filter capacitor. There is a problem that it is necessary to add an external filter capacitor bank of high withstand voltage consisting of or to limit the performance.

When an external filter capacitor bank is additionally installed, when a short circuit accident occurs in the switching element of the inverter circuit, the discharge current from the external filter capacitor bank suddenly flows into the part of the switching element where the short circuit occurs. However, there is a problem that the switching element may be destroyed on a large scale.

The present invention has been made in view of the above-mentioned problems of the prior art, and by adding an external filter capacitor bank composed of a relatively small amount of low withstand voltage capacitors and a simple peripheral circuit, a pantograph can be provided. An object of the present invention is to provide a power conversion device for an electric vehicle that can extend the operation duration of an inverter circuit with respect to a disconnection.

Another object of the present invention is to provide a power conversion device for an electric vehicle which can prevent damage such as element destruction of an inverter circuit with a minimum when a short circuit accident occurs in a switching element of an inverter circuit. ..

[0020]

The invention according to claim 1 is
An electric vehicle that receives DC power from an overhead wire or a third railroad track via a pantograph, supplies it to an inverter circuit connected in parallel via a filter capacitor, converts DC / AC power, and supplies it to various loads of an electric car. In this power converter, an external filter capacitor bank including a self-extinguishing semiconductor element and a plurality of capacitors charged through the self-extinguishing semiconductor element in parallel with the filter capacitor, and the external filter capacitor A rectifying element that permits only discharge from the bank to the DC input side of the inverter circuit and the voltage across the external filter capacitor bank are detected, and the voltage across this bank is lower than the rated value of the input DC voltage of the inverter circuit. Means for controlling on / off operation of the self-arc-extinguishing semiconductor device so as to maintain a predetermined set voltage It is those with a.

According to a second aspect of the present invention, in the electric power converter of the electric vehicle, a plurality of capacitors are connected in parallel to the filter capacitor and supply DC power to the inverter circuit even when the pantograph is momentarily disconnected. The external filter capacitor bank consisting of and the discharge current value from this external filter capacitor bank is detected,
A means for electrically disconnecting the inverter circuit and the external filter capacitor bank is provided when an arm short circuit accident of the inverter circuit occurs.

According to a third aspect of the present invention, in the electric vehicle power conversion device, the filter capacitor is connected in parallel with the electric power conversion device.
Self-extinguishing semiconductor element, external filter capacitor bank consisting of a plurality of capacitors charged through the self-extinguishing semiconductor element, and discharge from the external filter capacitor bank to the DC input side of the inverter circuit Rectifying element that permits only the above, and the voltage across the external filter capacitor bank is detected. A means for controlling the on / off operation of the arc-shaped semiconductor element and a discharge current value from the external filter capacitor bank are detected, and the inverter circuit and the external filter capacitor bank are electrically connected to each other when the arm short circuit of the inverter circuit occurs. And means for shutting off.

[0023]

In the electric power converter for an electric vehicle according to the first aspect of the present invention, during normal operation, the voltage detection means controls the external filter capacitor bank to cause the voltage to exceed the rated voltage via the self-extinguishing semiconductor element. The battery is charged to maintain a low predetermined voltage.

When the pantograph is disconnected, when the DC input voltage drops to a predetermined value during the continuous operation of the inverter circuit and becomes equal to the voltage across the external filter capacitor bank, the rectifying element operates and this The current charged in the attached filter capacitor bank is discharged to the inverter circuit, and the operation of the inverter circuit is continued for a longer time.

Thus, by continuing the operation of the inverter circuit by discharging the external filter capacitor bank under the set voltage lower than the rated voltage, it is possible to lengthen the operation continuation time.

Further, in the electric power converter for an electric vehicle according to a second aspect of the present invention, when the switching element of the inverter circuit is destroyed and a short circuit of the upper and lower arms occurs, an overcurrent is discharged from the external filter capacitor bank. Is detected, the inverter circuit is electrically cut off from the external filter capacitor bank, and an excessive discharge current does not suddenly flow into the inverter circuit from the external filter capacitor bank. The destruction can be minimized.

Further, in the electric power converter for an electric vehicle according to a third aspect of the present invention, during normal operation, the rated voltage is applied to the external filter capacitor bank through the self-extinguishing type semiconductor element under the control of the voltage detecting means. It is charged to maintain a predetermined voltage lower than the above, and when the pantograph is disconnected, the DC input voltage decreases to a predetermined value during continuous operation of the inverter circuit, and the voltage across the external filter capacitor bank becomes When they become equal, the rectifying element operates to discharge the current charged in this external filter capacitor bank to the inverter circuit, and the operation of the inverter circuit is continued for a longer time, so that the voltage is set below the rated voltage. The operation of the inverter circuit can be continued by discharging the external filter capacitor bank.

At the same time, when the switching element of the inverter circuit is destroyed to cause a short circuit of the upper and lower arms, it is detected that an overcurrent has been discharged from the external filter capacitor bank, and the inverter circuit and the external circuit are connected. It is possible to electrically cut off the filter capacitor bank and prevent an excessive discharge current from suddenly flowing into the inverter circuit from the external filter capacitor bank, thereby minimizing damage to the elements of the inverter circuit.

[0029]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a circuit block diagram of an embodiment of the invention described in claim 1. The parts common to the circuit components of FIGS. 7 and 8 shown as a conventional example are designated by the same reference numerals. Is shown.

As a feature of this embodiment, the elements newly added to the conventional example are that the external filter capacitor bank 14 provided in parallel with the fill capacitor 6 and the voltage across the filter capacitor 6 are 1500V, which is the rated voltage. Is a rectifying element 15 that permits only discharge of the external filter capacitor bank 14 when the voltage reaches a predetermined low voltage, for example, 1100 V or less.

Further, the GTO as a self-extinguishing rectifier
Thyristor 16, External filter capacitor bank 14
The voltage detector 17 as a means for turning on the gate of the GTO thyristor 16 when the voltage between both ends of the GTO thyristor 16 and the voltage detector 17 is detected at a predetermined set voltage or less. Limiting resistors 18 and 19 for limiting are provided.

Next, the operation of the electric vehicle power converter having the above-described structure will be described.

When the electric car is running while the pantograph 2 is in contact with the overhead line or the third rail 1 to collect current, the DC power having a rated voltage of 1500 V collected by the pantograph 2 is the filter reactor 4 and the filter capacitor 6. It is input to the inverter circuit 7 via the, is converted into direct current and alternating current here, and is output to various loads as alternating current of a predetermined voltage.

At this rating, the voltage detector 17 detects the voltage across the external filter capacitor bank 14 and is the set voltage until the external filter capacitor bank 14 is charged to a predetermined set voltage. 110
The gate of the GTO thyristor 16 is turned on until the voltage reaches 0V, and charging is performed.

When the voltage across the external filter capacitor bank 14 reaches the set voltage 1100V, the voltage detector 17 detects this and turns off the gate of the GTO thyristor 16 to stop charging.

After that, the voltage detector 17 always detects the voltage across the external filter capacitor bank 14,
Every time the voltage between both ends becomes 1100 V or less due to discharge, the gate of the GTO thyristor 16 is turned on and recharge is repeated.

Therefore, when the pantograph 2 is separated from the overhead line or the third rail 1 while operating at a rated voltage of 1500 V, as shown in FIG. 2, a predetermined set voltage 1100 V lower than the rated voltage 1500 V is reached until about 10 ms. In the meantime, the inverter circuit 7 continues to operate.

When the set voltage drops to 1100V, the voltage across the external filter capacitor bank 14 becomes equal to the voltage across the filter capacitor 6, the rectifying element 15 turns on, and the external filter capacitor bank 14 is charged. The generated current is discharged and output to the inverter circuit 7. Then, thereafter, the operation of the inverter circuit 7 is continued by the discharge current of the external filter capacitor bank 14 until about 60 ms when the stop voltage of the inverter circuit 7 reaches 900V.

Here, when a 1500 k overhead wire 200 kVA inverter circuit separates for 60 ms, a capacitor bank with a capacity of 12600 μF is required in the conventional example to obtain the filter capacitor voltage as shown in FIG. In addition to the 9S9P filter capacitor 6 that is being
It was necessary to add 225 external filter capacitor banks connected to S25P.

On the other hand, in the above embodiment, as shown in FIG. 2, the overhead line voltage at the time of disconnection is from DC 1500V to 11V.
Power is not supplied from the external filter capacitor bank 14 while the voltage drops to 00V, and power is supplied from the external filter capacitor bank 14 added between the set voltage 1100V and the set value of the protection voltage 900V. I have to. Therefore, the time Δt required for the voltage to drop to 1100 V is 126 A × Δt = 3300 μF × (1500 V-1100 V) according to the equation (2), and Δt = about 10 ms.

The capacitance C of the external filter capacitor bank 14 required when the voltage from 1100 V to 900 V drops is i = 200 × 10 ³ VA × 0..3 from the above equations (1) and (2). 85 / (0.9 * 1100V) = about 172A 172A * (60ms-10ms) = C * (1100V-900V) and C = about 43000 [mu] F. At this time, the voltage applied to the external filter capacitor bank 14 is 1100 V at the maximum, so that a capacitor having a rated voltage of 400 V can be realized by 120 capacitors of 3S40P for 3S (series) connection. As described above, by lowering the withstand voltage of the capacitors, 100 or more capacitors can be reduced as compared with the conventional example.

Further, in the conventional example, the volume of the external filter capacitor bank is about 0.276 m ³ , and the weight is about 1.
Although the weight is 60 kg, the circuit added in this embodiment includes a rectifying element 15 in addition to the external filter capacitor bank 14.
GTO thyristor 16, voltage detector 17, resistors 18, 1
Approximately 0.117 m ³ including 9 and weight of about 50 kg
Becomes That is, the volume is about 2/5 and the weight is about 1/3 of that of the conventional example, which means that the size and weight can be greatly reduced.
In addition, since the capacitors forming the external filter capacitor bank 14 operate only when the voltage is low, the life of the capacitors is longer than that of the conventional example, a general electrolytic capacitor can be used, and the cost can be reduced.

The present invention is not limited to the above-described embodiments, but as a self-arc-extinguishing type semiconductor device, a GTR (Giant Transistor) or an IGBT (Insula) is used instead of the GTO thyristor.
A tedGate Bipolar Transistor) element can also be used.

Next, the embodiment of the invention described in claim 2 is shown in FIG.
~ It demonstrates based on FIG.

The embodiment shown in FIG. 3 differs from the conventional power conversion device shown in FIGS. 7 and 8 in that the filter capacitor 6 is connected in parallel with the external filter capacitor device 2
5 is connected. This external filter capacitor device 25 is connected to the external filter capacitor bank 14 similar to that of the embodiment of FIG. , A diode 21 as a rectifying element connected in anti-parallel with the GTO thyristor 20, a current detector 22 for detecting a discharge current of the external filter capacitor bank 14 connected in series with the GTO thyristor 20, and this current detection. An abnormal rapid discharge detection circuit 23 that sends a signal to turn off the GTO thyristor 20 when the discharge current value detected by the device 22 is monitored and when it is detected that the overcurrent is discharged from the external filter capacitor bank 14. A gate drive circuit 24 that receives a signal and turns off the GTO thyristor 20. Are al configuration.

Next, the operation of the electric vehicle power converter having the above-described structure will be described.

The direct current collected from the pantograph 2 is
While charging the filter capacitor 6, the diode 2
The external filter capacitor bank 14 is also charged via 1. The DC current collected from the pantograph 2, the discharge current from the filter capacitor 6, and the discharge current from the external filter capacitor bank 14 are supplied to the inverter circuit 7, and are converted into three-phase AC and output. During operation of the inverter circuit 7, the external filter capacitor bank 14 is charged through the diode 21 and G
The operation of discharging through the TO thyristor 20 is repeated.

In the power conversion device for an electric vehicle having the above-described structure, the protection operation when the upper and lower arms of the inverter circuit 7, which has been a problem in the past, causes a short circuit accident will be described. The overcurrent tries to flow into the inverter circuit 7 via the GTO thyristor 20, but the current detector 22 connected in series to the GTO thyristor 20 detects the overcurrent, and the abnormal rapid discharge detection circuit 23 causes the GTO thyristor 20 to detect. Is sent to the gate drive circuit 24 to turn off the GTO thyristor 20 to prevent an overcurrent from being discharged from the external filter capacitor bank 14 and flowing into the inverter circuit 7.

Next, the operation of the abnormal rapid discharge detection circuit 23 will be described in more detail with reference to FIG. 4. Regarding the discharge current value i of the external filter capacitor bank 14 detected by the current detector 22, normal operation is performed by two methods. , Abnormality is judged. One of them is a temporal change (di) of the discharge current value i.
/ Dt), the discharge current value i is held for one sampling via the sampling and holding circuit (SH) 26, and the difference between the current value one sampling before and the current value is passed through the subtraction circuit 27. Then, the difference is compared with the reference value C1 by the comparator 28. If the difference is larger than the reference value C1, the "H" signal is output, and if the difference is smaller than the reference value C1, the "L" signal is output. The other one is a method of monitoring the magnitude of the discharge current value i.
Is compared with a reference value C2 by a comparator 29. If it is larger than the reference value C2, an "H" signal is output, and if it is smaller than the reference value C2, an "L" signal is output. The output signals of these comparators 28 and 29 are passed through the OR gate 30, and if this output is "H", the GTO thyristor off signal is sent to the gate drive circuit 24. That is, if a value larger than the reference value C1 or C2 is shown by any of the above methods, the "H" signal is output from the OR gate 30, the GTO thyristor 20 is turned off, and when the short circuit accident of the inverter circuit 7 occurs, This prevents an overcurrent due to a rapid discharge from flowing into the inverter circuit 7 from the external filter capacitor bank 14.

As described above, the two methods are used to prevent the release of the overcurrent by immediately detecting that the upper and lower arms of the inverter circuit 7 are short-circuited and the external filter capacitor bank 14 has generated the overcurrent. This is to turn off the thyristor 20. It should be noted that the reference values C1 and C2 are easily different because there is a very large difference between the current value itself and the time change of the current between the normal time and the abnormal time when the upper and lower arms of the inverter circuit 7 are short-circuited. You can decide.

As described above, in the electric vehicle power converter according to the second embodiment of the present invention, even if the upper and lower arms of the inverter circuit 7 are short-circuited, the excess discharge from the external filter capacitor bank 14 is caused. Since the current is detected and the GTO thyristor 20 is turned off by the functions of the abnormal rapid discharge detection circuit 23 and the gate drive circuit 24, overcurrent is prevented from flowing in the inverter circuit 7 and the destruction of the switching element of the inverter circuit 7 is minimized. It's hard to stop.

Next, based on FIG. 5 and FIG.
Examples of the described invention will be described.

The embodiment shown in FIG. 5 is a combination of the embodiment of the invention of claim 1 shown in FIG. 1 and the embodiment of the invention of claim 2 shown in FIG. The difference from the conventional example shown in FIGS. 7 and 8 is that an external filter capacitor device 31 is connected in parallel with the filter capacitor 6.

This external filter capacitor device 31
The same elements as those of the embodiment of FIG. 1 include an external filter capacitor bank 14 provided in parallel with the fill capacitor 6 and a predetermined set voltage whose voltage across the filter capacitor 6 is lower than the rated voltage of 1500V, For example, the rectifying element 15 that allows only the discharge of the external filter capacitor bank 14 when the voltage becomes 1100 V or less, the GTO thyristor 16 as a self-extinguishing rectifier element, and the voltage across the external filter capacitor bank 14 is constantly detected. In addition, the voltage detector 17 as a means for turning on the gate of the GTO thyristor 16 when the voltage becomes equal to or lower than a predetermined set voltage, and the limiting resistance for limiting the current to each of the GTO thyristor 16 and the voltage detector 17. 1
8 and 19 are provided.

Then, the voltage detector 17 turns off the GTO thyristor 16 when the voltage detection element 32 for detecting the voltage of the external filter capacitor bank 14 and the voltage detection value of the voltage detection element 32 become the comparison value or more. Then, if it becomes less than or equal to the comparison value, an overhead wire voltage detection circuit 33 that outputs an on / off command signal for turning on the GTO thyristor 16, and on / off control of the GTO thyristor 16 is performed based on the on / off command signal from the overhead wire voltage detection circuit 33. It is composed of a gate drive circuit 34.

The external filter capacitor device 31 is also connected in series to the external filter capacitor bank 14 with the discharge direction of the external filter capacitor bank 14 as the forward direction, as a common element with the embodiment shown in FIG. GTO thyristor 20 that is normally turned on and this G
A diode 21 as a rectifying element connected in antiparallel with the TO thyristor 20, a current detector 22 for detecting a discharge current of the external filter capacitor bank 14 connected in series with the GTO thyristor 20, and this current detector 22.
The abnormal rapid discharge detection circuit 23 that sends a signal to turn off the GTO thyristor 20 when the discharge current value detected by the external filter capacitor bank 14 is detected and the overcurrent is discharged from the external filter capacitor bank 14, and this signal. Receiving G
Gate drive circuit 24 for turning off the TO thyristor 20
Is equipped with.

Next, the operation of the electric power converter for an electric vehicle according to the third embodiment of the invention having the above-described structure will be described.

At the rated time, the overhead line voltage detection circuit 3 detects the overhead line voltage with the voltage detecting element 32 of the voltage detector 17.
3 and the gate drive circuit 34 perform switching control of the GTO thyristor 16, so that the external filter capacitor bank 14 for disconnection has a substantially constant voltage value (here, 1100V) slightly higher than the low voltage protection voltage (here, 900V). Set to)) to charge.

The overhead wire voltage detection circuit 3 of the voltage detector 17
The control function of No. 3 will be described based on the block diagram of FIG. 6. The overhead wire voltage value v detected by the voltage detection element 32 is given to the two comparators 35 and 36, where the reference value D1 (here, 1100V) is used. When the voltage value v is high, GT
When the OFF signal of the O thyristor 16 is output and the voltage value v is lower than the reference value D2 (here, 1100V), GT
The ON signal of the O thyristor 16 is output, and the gate drive circuit 34 receives this ON / OFF signal to control the switching of the GTO thyristor 16, and the external filter capacitor bank 14 is lower than the rated voltage 1500V of the overhead line or the third rail 1 It is charged and maintained at a substantially constant set voltage of 1100V.

When the voltage detected by the voltage detecting element 32 is higher than 1100 V, the external filter capacitor bank for disconnection 14 is blocked by the rectifying element 15 and is not discharged, and the disconnection of the pantograph 2 occurs. When the voltage of the capacitor 6 becomes 1100 V or less, the rectifying element 15 is turned on and the power of the external filter capacitor bank 14 is supplied to the inverter circuit 7.
The change in the input voltage of the inverter circuit 7 at this time is shown in FIG.
It becomes the one shown in. Also in this third embodiment, the voltage applied to the external filter capacitor bank 14 is 1100V at maximum, as in the embodiment of the invention described in claim 1 shown in FIG. If so, 3 as a 3S (series) connection
It can be realized with 120 capacitors of S40P. As described above, by lowering the withstand voltage of the capacitors, 100 or more capacitors can be reduced as compared with the conventional example.

Also, the external filter capacitor bank 1
Although adding 4 is effective in extending the disconnection time of the pantograph 2, if an arm short circuit occurs in the inverter circuit 7 at the same time, the external filter capacitor bank 14
There is a risk that a large current will flow from the device to damage the elements and even the surrounding circuit components. To prevent this, when a short circuit accident occurs between the upper and lower arms of the inverter circuit 7, the abnormal rapid discharge detection circuit 23 and The gate drive circuit 24 shuts off the GTO thyristor 20.

That is, as described with reference to FIG. 4 as the operation of the embodiment of the invention described in claim 2, the overcurrent emitted from the external filter capacitor bank 14 is GT.
Although it tries to flow into the inverter circuit 7 through the O thyristor 20, the current detector 22 connected in series to the GTO thyristor 20 detects an overcurrent, and the abnormal rapid discharge detection circuit 23 turns off the GTO thyristor 20. A signal is sent to the gate drive circuit 24 to turn off the GTO thyristor 20 and prevent the overcurrent emitted from the external filter capacitor bank 14 from flowing into the inverter circuit 7.

Thus, in the electric vehicle power converter of the embodiment of the present invention as defined in claim 3, the external filter capacitor device for extending the disconnection time of the pantograph can be constructed in a relatively small size. It is possible to prevent an overcurrent from flowing into the switching element of the inverter circuit due to the presence of the external filter capacitor device when a short circuit of the upper and lower arms of the inverter circuit occurs.

In each of the above embodiments, the capacity, configuration, and comparison reference value C1 of the external filter capacitor bank are set.
C2, D1, D2, etc. are not limited and can be changed as necessary.

[0066]

As described above, according to the first aspect of the present invention, the inverter circuit when the pantograph is disconnected can be continuously operated for a long time, and the external filter capacitor bank is charged with a relatively low voltage. Because of this, because of the configuration of this capacitor bank, it is possible to configure the capacitor with a low withstand voltage, downsizing,
Cost reduction can be achieved.

According to the second aspect of the present invention, when the switching element of the inverter circuit is destroyed and a short circuit of the upper and lower arms occurs, an excessive discharge current from the external filter capacitor bank is suddenly generated. It is possible to prevent the element from flowing into the inside and to prevent the destruction of the element at the time of a short circuit accident of the inverter circuit.

Further, according to the third aspect of the present invention, the external filter capacitor bank can be downsized and the cost can be reduced, and at the same time, even if the external filter capacitor bank is added, the external filter capacitor bank can be externally operated in the event of a short circuit of the inverter circuit. It is possible to surely prevent an overcurrent from flowing into the inverter circuit from the attached filter capacitor bank, and to prevent element destruction to a minimum.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the invention described in claim 1.

FIG. 2 is a timing chart showing the operation of the above embodiment.

FIG. 3 is a circuit block diagram of an embodiment of the invention described in claim 2.

FIG. 4 is a block diagram showing a control function of an abnormal rapid discharge detection circuit in the above embodiment.

FIG. 5 is a circuit block diagram of an embodiment of the invention according to claim 3;

FIG. 6 is a block diagram showing a control function of an overhead line voltage detection circuit in the above embodiment.

FIG. 7 is a circuit block diagram of a conventional example.

FIG. 8 is a circuit block diagram of another conventional example.

FIG. 9 is a timing chart showing the operation of a conventional example.

[Explanation of symbols]

 1 Overhead line or 3rd rail 2 Pantograph 6 Filter capacitor 7 Inverter circuit 14 External filter capacitor bank 15 Rectifier element 16 GTO thyristor 17 Voltage detector 20 GTO thyristor 21 Diode 22 Current detector 23 Abnormal sudden discharge detection circuit 24 Gate drive circuit 25 External filter capacitor device 32 Voltage detection element 33 Overhead line voltage detection circuit 34 Gate drive circuit

Claims (3)

[Claims] 1. A variety of loads of an electric vehicle that receives DC power from an overhead wire or a third rail via a pantograph and supplies it to an inverter circuit connected in parallel via a filter capacitor to convert DC / AC power. In the power conversion device for an electric vehicle that supplies the self-extinguishing type semiconductor element in parallel with the filter capacitor, and an external filter capacitor bank including a plurality of capacitors charged through the self-extinguishing type semiconductor element. A rectifying element that allows only discharge from the external filter capacitor bank to the DC input side of the inverter circuit, and a voltage across the external filter capacitor bank is detected, and the voltage across the rectifier element is the input DC voltage of the inverter circuit. ON / OFF of the self-extinguishing type semiconductor device so as to maintain a predetermined set voltage lower than the rated value of Power conversion apparatus for an electric vehicle comprising a means for controlling the work. 2. Various loads of an electric vehicle by taking in DC power from an overhead wire or a third rail via a pantograph and supplying it to an inverter circuit connected in parallel via a filter capacitor to convert DC / AC power. In the power conversion device for an electric vehicle to be supplied to an external filter capacitor bank, which is connected in parallel to the filter capacitor and comprises a plurality of capacitors for supplying DC power to the inverter circuit even when the pantograph is momentarily disconnected, An electric vehicle comprising means for detecting a discharge current value from the external filter capacitor bank and electrically disconnecting the inverter circuit and the external filter capacitor bank in the event of an arm short circuit of the inverter circuit. Power converter. 3. Various loads of an electric vehicle by taking in DC power from an overhead wire or a third rail via a pantograph and supplying it to an inverter circuit connected in parallel via a filter capacitor to convert DC / AC power. In the power conversion device for an electric vehicle that supplies the self-extinguishing type semiconductor element in parallel with the filter capacitor, and an external filter capacitor bank including a plurality of capacitors charged through the self-extinguishing type semiconductor element. A rectifying element that allows only discharge from the external filter capacitor bank to the DC input side of the inverter circuit, and a voltage across the external filter capacitor bank is detected, and the voltage across the rectifier element is the input DC voltage of the inverter circuit. ON / OFF of the self-extinguishing type semiconductor device so as to maintain a predetermined set voltage lower than the rated value of A means for controlling the operation, and a means for detecting the discharge current value from the external filter capacitor bank, and electrically disconnecting the inverter circuit and the external filter capacitor bank at the time of an arm short circuit accident of the inverter circuit. An electric vehicle power conversion device provided.