JPH0556502A - Auxiliary power supply for vehicle - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] To prevent the load connected to the output wiring and the load connected to other wiring from being adversely affected by making the fluctuation of the potential to the vehicle body gentle. .. [Structure] The high voltage direct current of the DC overhead wire 1 is converted into an alternating current by a first direct current / alternating current conversion circuit 6, insulated and transformed by a transformer 7, and once rectified by a rectifier 8 into a direct current. The second DC / AC converter circuit 10 converts the AC voltage again into an AC voltage, and the sine wave shaping circuits 11 and 12 shape and output the sine wave AC. The sine wave AC output as the final AC output 13 is connected between the vehicle body of the electric vehicle and the vehicle body grounding circuit grounded to the vehicle body of the electric vehicle. The waveform should fluctuate so that the load connected to the output wiring and the load connected to other wiring are not adversely affected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention converts a high voltage direct current from a DC overhead wire into an alternating current, insulates and transforms it with a transformer, rectifies it once to make a direct current, and converts this direct current into an alternating current again to obtain a desired voltage. The present invention relates to a vehicle auxiliary power supply device that outputs an AC voltage.

[0002]

2. Description of the Related Art Conventionally, a high voltage direct current of a DC overhead wire is converted into an alternating current, which is insulated and transformed by an insulating transformer, which is once rectified into a direct current, and this direct current is converted into an alternating current again to obtain a desired alternating voltage. In the vehicle auxiliary power supply device for outputting, the positive side or the negative side of the DC output that has been rectified and converted into DC has been grounded to the electric vehicle body.

[0003]

However, in such a conventional vehicle auxiliary power supply device, since the direct current portion is fixed to the electric potential of the vehicle body of the electric vehicle, this fixed electric potential is applied to the semiconductor switching element. When the AC conversion is performed by the switching operation of, the AC-converted voltage with respect to the vehicle body potential is, as shown in FIG. 4, 0V at the same cycle as the switching operation frequency of the semiconductor switching element and the DC voltage before the AC conversion. It suddenly fluctuated in the shape of a rectangular pulse between them.

An alternating current having a potential with respect to the vehicle body that fluctuates between 0V and the direct current voltage before the alternating current conversion is applied to a load connected to the alternating current and other wirings mounted on the vehicle body together with the alternating current wiring. Since the potential variation with respect to the vehicle body is given, there is a problem that a load connected to the other wirings may be adversely affected such as malfunction or destruction especially when the load is an electronic device.

Therefore, an insulating transformer may be used as a measure for preventing an AC having a potential with respect to the vehicle body varying between 0V and a DC voltage before AC conversion from being applied to the load. In the case of using the insulating transformer, it is necessary to use the insulating transformer for the amount of electric power supplied to the load, which causes a problem that the device as a whole is large, heavy and large.

The present invention has been made in view of the above-mentioned conventional problems, and it is possible to reduce the size and weight of the electronic device so as to output a sharp potential fluctuation which adversely affects the load of electronic equipment such as malfunction or destruction. It is an object of the present invention to provide an auxiliary power supply device for a vehicle that does not have a vehicle.

[0007]

The vehicle auxiliary power supply device of the present invention includes a first DC / AC conversion circuit for converting DC power from a current collector into AC power, and the first DC / AC conversion circuit. A transformer having a primary winding connected to the output side of the transformer, a rectifier connected to the secondary winding of the transformer and converting AC power into DC power, and a rectifier converting the DC output of the rectifier into AC power. 2, a DC / AC conversion circuit, a waveform shaping circuit that shapes the output of the second DC / AC conversion circuit into a sine wave AC, and is connected between the sine wave output side of the waveform shaping circuit and the electric vehicle body. The vehicle body grounding circuit grounds the sine wave alternating current to the electric vehicle body.

[0008]

In the vehicle auxiliary power supply device of the present invention, the high voltage DC of the DC overhead wire is converted into AC by the first DC / AC conversion circuit, insulated and transformed by the transformer, and once rectified by the rectifier, the DC Then, the direct current is converted into alternating current again by the second direct current / alternating current conversion circuit to obtain a desired alternating current power, and the sine wave shaping circuit further shapes the waveform into a sine wave alternating current and outputs it.

By connecting the sine wave AC output as the final AC output and the electric vehicle body to the vehicle body grounding circuit grounded to the electric vehicle body, the fluctuation waveform of the electric potential with respect to the vehicle body is converted into a sine waveform. The load is connected to the other wiring so that it has a waveform that changes smoothly and does not give a sharp change in the potential to the vehicle body to the load connected to the final AC output and other wiring that is equipped with the AC output wiring. Do not have an adverse effect on.

[0010]

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 present invention, in which a high-voltage DC power is collected from a high-voltage DC overhead wire 1 and a collector 2 is provided.
The DC power thus taken in is grounded to the track 5 via the grounding brush 3 and the wheels 4.

In addition, the vehicle auxiliary power supply device of this embodiment has the following features with respect to the high-voltage DC power taken from the collector 2.
A first DC / AC conversion circuit 6 for DC / AC conversion, an output of the first DC / AC conversion circuit 6 is connected to a primary winding, and an insulation transformer 7 for performing insulation transformation, and this insulation transformer 7 A rectifier 8 that is connected to the secondary winding and that converts AC power into DC power, a second DC / AC conversion circuit 10 that reconverts the DC output 9 of this rectifier 8 into AC power, and this second DC A reactor 11 and a capacitor circuit 12 as a sine wave waveform shaping circuit connected to the output of the AC conversion circuit 10 are provided, and the output of this capacitor circuit 12 is output as the final AC output 13.

Further, as a feature of the present invention, the vehicle auxiliary power supply device of this embodiment is provided with a grounding auto transformer 14 having a three-point star connection to the final AC output 13 as a vehicle body grounding circuit and having a midpoint. The grounding auto transformer 14 is connected to each of the three phases, and the midpoint is grounded to the vehicle body. Next, the operation of the vehicle auxiliary power supply device having the above configuration will be described.

The DC power taken from the high voltage overhead wire 1 by the current collector 2 is converted into AC by the first DC / AC conversion circuit 6, and is stepped down by the insulating transformer 7 to a voltage necessary for this auxiliary power system. Then, it is passed through the rectifier 8 and reconverted into DC power, and this DC output 9 is reconverted into desired AC power by the second DC / AC conversion circuit 10.

The second DC / AC conversion circuit 1
The rectangular wave alternating current, which is an output of 0, is shaped into a sine wave for each phase by the reactor 11 and the capacitor circuit 12,
As the final AC output 13, a sine wave AC as shown in FIG. 2 is obtained.

The grounding autotransformer 14 is connected to the sine wave three-phase AC output 13 at each of the three-phase portions, the middle point of which is grounded to the vehicle body. Is a sine wave as shown in FIG.
Therefore, the load connected to the AC output 13 and other wiring mounted on the vehicle body together with the wiring of the AC output 13 do not undergo a sharp change in the electric potential with respect to the vehicle body, and the load connected to the other wiring is not affected. There will be no adverse effect on it.

The present invention is not limited to the above embodiment, but may have the circuit configuration shown in FIG. In the second embodiment, the grounding autotransformer 14 used in the first embodiment shown in FIG.
The three resistors are connected to the wiring of each of the three phases, and the middle point is grounded to the vehicle body.

Also in the second embodiment, since the AC output 13 whose waveform is shaped into a sine wave AC by the reactor 11 and the capacitor circuit 12 is grounded to the vehicle body, the variation of the electric potential with respect to the vehicle body becomes a sine wave. Since no abrupt change occurs, no adverse effect is exerted on the load connected to the other wiring connected to the output 13.

In the embodiment shown in FIG. 3, three resistors 15 connected to each of the three-phase wirings are used to ground the midpoint, but in addition to this, U-phase, V-phase, Alternatively, the W phase may be directly grounded, or the U phase, V phase, or W phase may be grounded via a resistor.

[0020]

As described above, according to the present invention, a grounding autotransformer or a grounding resistor is provided for the final AC output obtained by sine-wave shaping the output of the second DC / AC conversion circuit. Since the connection is made and the midpoint thereof is grounded to the vehicle body, the variation of the potential to the vehicle body can take the form of a sine wave, and the potential to the vehicle body fluctuates sharply like a pulse as in the past. Therefore, there is no possibility that a load connected to the output wiring or a load connected to another wiring connected to the output wiring is adversely affected by a sharp potential change.

[Brief description of drawings]

FIG. 1 is a circuit block diagram of an embodiment of the present invention.

FIG. 2 is a fluctuation waveform diagram of the electric potential with respect to the vehicle body in the above embodiment.

FIG. 3 is a circuit block diagram of another embodiment of the present invention.

FIG. 4 is a variation waveform diagram of a potential with respect to a vehicle body according to a conventional example.

[Explanation of symbols]

 1 ... High-voltage overhead wire 2 ... Current collector 3 ... Ground brush 4 ... Wheel 5 ... Track 6 ... First DC / AC conversion circuit 7 ... Insulation transformer 8 ... Rectifier 9 ... DC output 10 ... Second DC / AC conversion circuit 11 ... Reactor 12 ... Capacitor circuit 13 ... AC output 14 ... Grounding auto transformer 15 ... Grounding resistor

Claims (1)

[Claims] 1. A first DC / AC conversion circuit for converting DC power from a current collector into AC power, and a transformer having a primary winding connected to an output side of the first DC / AC conversion circuit. A rectifier that is connected to the secondary winding of the transformer and that converts AC power into DC power; a second DC / AC conversion circuit that converts the DC output of the rectifier into AC power; and the second DC A waveform shaping circuit that shapes the output of the AC conversion circuit into a sine wave AC, and a vehicle body grounding that is connected between the sine wave output side of the waveform shaping circuit and the electric vehicle body to ground the sine wave AC to the electric vehicle body An auxiliary power supply device for a vehicle, which comprises a circuit.