JP2561276B2 - AC electric car power supply - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a power supply device for an AC electric vehicle, and particularly to a PWM
The present invention relates to a power supply device using a (pulse width modulation) converter.

[Conventional technology]

The power supply device of an AC electric vehicle is disclosed in "History of development of drive system by non-rectifier electric motor in JNR" (June 1986, Science of electric vehicles). In this conventional device, a charging resistor is inserted in series in a short-time circuit in order to suppress a charging current to a filter capacitor, as shown in the above-mentioned publicly known document. The above-mentioned document shows an example of a DC overhead wire, but in the case of an AC overhead wire, as in the case of a DC overhead wire, charging resistance may be placed on the DC full-current side or on the AC side. In the case of an AC overhead wire, the secondary winding of the pressurizer is usually divided into 2 to 4 to reduce high frequency current.
On the other hand, recently, PWM converters, which are self-excited converters, have been used for the purpose of power factor improvement. In this way, the secondary winding is multi-divided, and the PWM converter is connected in parallel as seen from the DC side, and depending on the size of the control capacity (drive motor capacity x number of units), the charging resistor and its short circuit Since the single-unit capacity of the short-circuit switch can be smaller by inserting the switch on the AC side than on the DC full-current side, the versatility of the device may be excellent in some cases. When the charging resistor and its short-circuit switch are placed on the AC side, the PWM converter will feed parallel power to the DC side, so it is possible to put them in each secondary circuit.

However, especially for those having a large control capacity, whether the charging resistor and its short-circuit switch are placed on the DC full-current side or the AC side poses problems in terms of space, weight, and cost in terms of the device configuration. .

[Problems to be solved by the invention]

The above-mentioned conventional technique has a problem in that the charging resistor and its short-circuiting switch occupy a large space and weight in terms of the device structure, although they are not essential devices in the sense of speed control parts of an electric vehicle. Therefore, it is an object of the present invention to provide a power supply device for an AC electric vehicle in which a means for suppressing an overcurrent due to charging of a filter capacitor at the time of start-up can have a minimum device configuration.

[Means for solving problems]

The above-mentioned object is achieved by arranging the charging resistance charging means so that the filter capacitor can be charged by only one circuit converter.

That is, the primary winding is connected to the overhead wire (1) and
Transformer (4) having secondary windings (41, 42), a plurality of converters (12, 13) connected to each of the secondary windings and converting input AC power into DC power, and the plurality of converters An inverter (15) that receives the input of each DC output of the inverter and reversely converts this DC output into an AC output; and a filter capacitor (14) connected between the high voltage side and the low voltage side of the input end of the inverter. In a power supply device for an AC electric vehicle comprising :, a high voltage side circuit output end of any one of the plurality of converters and a connection point connected to a high voltage side input end of the inverter of the filter capacitor. In the meantime, a circuit consisting of one short-circuit switch (7) opened at the time of starting and a current limiting resistor (6) in parallel with this is connected in series, and is connected to the output end of the high-voltage side circuit of another converter (13). The filter capacitor The other short-circuit switch, which is opened at the time of start-up and is opened after the one short-circuit switch is opened when the charging of the filter capacitor is completed, between the connection point of the sensor and the input point on the high-voltage side of the inverter. It is characterized in that (8) is connected.

[Action]

According to the above configuration of the present invention, the parallel circuit of the short-circuit switch (7) and the charging resistor (6) is applied to only one converter (12) among a plurality of converters, and the other converters are charged during the charging period. The output of (13) is stopped by the short-circuit switch (8), so that the charging resistor may be of a size commensurate with the current capacity of the converter, and as a result, the power supply device can be made compact and lightweight. It will be.

〔Example〕

 Next, an embodiment of the present invention will be described with reference to the drawings.

The figure shows a circuit diagram of a power supply device according to the invention. In the figure, AC power from an AC overhead wire 1 is input to a transformer 4 via a pantograph and an AC circuit breaker 3. The transformer 4 has a primary winding, secondary windings 41 and 42, and a tertiary winding 43.
have. Since this transformer has two secondary windings 41 and 42, it is generally called a secondary bisection type. The PWM converters 12 and 13 are connected as secondary circuits to the secondary windings 41 and 42 of the transformer 4, respectively. These PWM converters 12 and 13 are composed of a GTO (gate turn-off thyristor bridge rectifier circuit), convert AC power to DC power when the AC electric vehicle is accelerating, and convert DC power to AC power when decelerating. Reverse conversion is used to regenerate alternating current.This GTO PWM control enables operation at a high power factor close to 1.0.
Details of PWM control by TO are omitted because they are not directly related to the present invention.

The high-voltage side of the output end of the converter 12 is connected to the input of the inverter 15 via the parallel circuit of the short-circuit switch 7 and the charging resistor 6 in series, and the low-voltage side of the converter 12 is connected to the low-voltage side of the inverter 15. . Meanwhile, converter 13
The high voltage side output terminal of is connected to the output terminal of the parallel circuit of the short circuit switch 7 and the charging resistor 6 via the short circuit switch 8, and the low voltage side is similarly connected to the low voltage side of the inverter to the input terminal. A filter capacitor 14 for removing ripples in the output voltage of the converter is connected to the high voltage side and the low voltage side of the input terminal of the inverter 15.

The inverter 15 converts the electric power converted into the direct current by the converter 12 or 13 back into an alternating voltage having a predetermined frequency again, and is generally composed of a variable voltage variable frequency (VVVF) type inverter. The output of the inverter 15 is three-phase power and is supplied to the AC motor 16.

 Next, the operation will be described.

The operation of the power supply device shown in the above configuration is as follows. First, the pantograph 2 rises and the AC overhead line 1
After making contact with, the AC breaker 3 is turned on. As a result, the tertiary load 11 is driven. The tertiary load circuit is usually formed by contacting an electric blower for forced air cooling of an electric device, a cooling / heating device, and an auxiliary power supply device. Therefore, in order to prevent service deterioration for passengers, it is preferable to continue the operation without opening the AC breaker 3 in case of a failure of the secondary circuit.

When the AC breaker 3 is turned on, the short-circuit switch 7 and the short-circuit switch 8 are open, so that the DC power converted by the converter 12 flows into the capacitor 14 via the charging resistor 6. In this case, since the short-circuit switch 8 of the converter 13 is completely open, the charging current flowing into the capacitor 14 is due only to the converter 12, but the current capacity of the charging resistor 6 corresponds to the current capacity of the converter 12. The size is enough. In this case, the charging time constant of the capacitor 14 is about 0.5 seconds.

When the charging of the capacitor 14 is completed by the above operation, the short-circuit switch 8 is closed and the DC power from the converter 13 is supplied to the inverter 15.

As described above, the charging resistance of the capacitor 14 is provided only on the output side of the converter 12, and the charging resistance that contributes to the charging of the capacitor 14 is only 6.
It is not necessary to provide a charging resistor corresponding to each of the above, and since the charging current is due to only the converter 12, the charging current in that case may have a current capacity corresponding to one converter. As a result, the device configuration of the power supply device of the AC electric vehicle is simplified and the weight is reduced.

〔The invention's effect〕

As described above, according to the present invention, the short-circuit switch and the charging resistance, which are not essentially required for the speed control of the AC electric vehicle, can be minimized. The weight can be reduced.

[Brief description of drawings]

FIG. 1 is a main circuit configuration diagram showing an embodiment of the present invention. 4 ... Transformer, 6 ... Charging resistor, 7 ... Short-circuit switch, 8 ... Short-circuit switch, 12, 13 ... Converter, 14 ...
… Filter capacitors, 15 …… Inverter, 16 …… Driving motor.

Claims (1)

(57) [Claims] 1. A transformer having a primary winding connected to an overhead wire and having a plurality of secondary windings, and a plurality of converters each connected to each of the secondary windings for converting input AC power into DC power. An inverter that receives the input of each DC output of the plurality of converters and inversely converts the DC output into an AC output,
In a power supply device for an AC electric vehicle comprising a filter capacitor connected between a high voltage side and a low voltage side of an input end of the inverter, a high voltage side circuit output end of any one of the plurality of converters, Between the connection point of the filter capacitor connected to the high-voltage side input terminal of the inverter, a short-circuit switch that is opened at the time of starting and a circuit including a current limiting resistor in parallel with the short-circuit switch are connected in series. Between the output terminal of the high voltage side circuit of another converter and the connection point of the filter capacitor connected to the high voltage side input terminal of the inverter, it is opened at the time of starting and the one short circuit is made when the charging of the filter capacitor is completed. A power supply device for an AC electric vehicle, to which another short-circuit switch that is opened after the switch is opened is connected.