JP3263974B2 - Momentary power failure prevention circuit of auxiliary power supply for electric vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an auxiliary power supply for an electric vehicle which is capable of continuing to supply electric power in the vehicle without a power failure of the auxiliary power supply even when the electric vehicle passes through a no-voltage section of an overhead line. Circuit.

[0002]

2. Description of the Related Art Electric vehicles require electric power for lighting and communication inside the vehicle, but in recent years, since air conditioning equipment has been largely introduced, electric power consumed inside the vehicle has been increasing more and more. If you try to take in the power consumption from the overhead line, the overhead line voltage is extremely high at 1500 VDC for DC electric vehicles and 20,000 VAC for AC electric vehicles, so it cannot be used as it is. Moreover, since the overhead line voltage fluctuates greatly, even in the AC electrified section, the overhead line voltage cannot be used simply by transforming the overhead line voltage to a low voltage with a transformer. Therefore, the high-voltage power taken from the overhead line is converted into a low-voltage, for example, 100 volts or 200 volts AC, which has no voltage fluctuation and is easy to use, and an auxiliary power supply is used for this power conversion.

[0003] As this auxiliary power supply device, a motor generator (hereinafter, referred to as M in the following) configured to drive a generator that outputs a desired voltage by a motor that is conventionally operated at an overhead line voltage (in an AC electrification section, pressure is reduced by a transformer). The abbreviation -G has been used. However, this MG has a large weight, has parts that are consumed with rotation, and requires much time for maintenance and inspection. Are being replaced by inverters and the like. Since power converters such as inverters composed of semiconductor switch elements are stationary devices, there are no consumable parts, so there is no need for maintenance and inspection, and there are many features such as light weight and quiet operation. are doing.

[0004]

When the railway is electrified,
Usually, overhead lines are divided at regular intervals, and power is supplied from different substations for each division. In the case of DC electrification, the output from adjacent substations can be given to a common overhead line (that is, parallel operation between substations is possible), so it is not necessary to divide the overhead lines finely. In the case of the above, the output of adjacent substations cannot be given to a common overhead line due to the voltage phase problem (that is, parallel operation between substations is not possible), and the overhead line must be insulated for each substation. Must be classified. Since the insulating portion separating the overhead wire is a no-voltage section, every time the electric vehicle passes through the no-voltage section while traveling, the power taken into the electric vehicle via the current collector is interrupted. . Conventional M
In the -G method, the generator continues to generate electric power while discharging the rotational energy held by the MG even if the electric power of the motor is interrupted when passing through the no-voltage section,
Although the output voltage may slightly fluctuate, the power supply in the vehicle will not be interrupted during the passage of the intersection.

However, when an inverter is used as an auxiliary power supply, this inverter has no means for storing energy like MG, so that the power supply in the vehicle is immediately cut off as soon as the electric vehicle enters a no-voltage section of the overhead line. There is a disadvantage. For example, the East Japan Railway Company's Tohoku Main Line divides overhead lines approximately every 16 km, so if an electric car runs at 90 km / h, it will pass through a no-voltage section every 10 minutes. The power supply in the car will be blackout. The inverter has a smoothing filter capacitor on its DC input side, but its capacity is not enough to cover the in-vehicle power during the period when the electric car passes through the no-voltage section of the overhead line, so the power is cut off by the filter capacitor. To prevent this, the capacity must be greatly increased.
Further, since the overhead wire voltage greatly fluctuates, if the overhead wire voltage is reduced, the energy stored in this filter capacitor is greatly reduced. Therefore, even if the overhead line voltage is the lowest, in order to cover the in-vehicle power during the above-described period, the capacity of the filter capacitor must be further increased (because the stored energy of the capacitor is proportional to the square of the voltage). ), There is a problem that the electric vehicle having a large inverter and having a limited installation space is difficult to mount. Therefore, MG is unavoidably used as the auxiliary power supply.

An object of the present invention is to use an inverter as an auxiliary power supply for an electric vehicle so that the power supply in the vehicle will not be interrupted when the electric vehicle passes through a no-voltage section of the overhead line.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, an instantaneous power failure prevention circuit of an electric vehicle auxiliary power supply according to the present invention comprises an electric vehicle auxiliary power supply for supplying in-vehicle electric power to a running electric vehicle. In the apparatus, an inverter that outputs an AC of a desired voltage and frequency by using either a DC taken by the electric vehicle from an overhead line or a DC obtained by rectifying an AC taken from the overhead line as a power source, and detects the presence or absence of an overhead line voltage. A voltage detecting means, a capacitor connected to the DC input side of the inverter via a switch element or a self-extinguishing semiconductor switch element, and a first charging means for charging the capacitor using the AC output from the inverter as a power supply. Charging means for charging the capacitor to a desired voltage while the switch element or the self-extinguishing semiconductor switch element is normally off, When the pressure detecting means detects no voltage on the overhead wire, the switch element is turned on, or the self-extinguishing type semiconductor switch element is controlled to be turned on and off at a desired conductivity. It is also possible to provide a second charging means using the direct current as a power source, and charge the capacitor by the second charging means. Further, since a filter capacitor is provided on the input side of the inverter, in order to avoid a risk of abnormally increasing the voltage of the filter capacitor provided on the input side of the inverter due to the inductance of the circuit, the filter capacitor and the filter capacitor are provided. It is assumed that the capacitor and the capacitor are connected via a diode.

[0008]

According to the present invention, a capacitor is connected to the DC input side of the inverter via a switch element. This capacitor is charged to a voltage as high as the elements constituting the inverter can tolerate. If the battery enters the no-voltage section, the capacitor is discharged until the voltage of the capacitor drops to the discharge end voltage. Assuming that the charge voltage is V _CH and the discharge end voltage is V _CL , the energy W that can be used for discharging the capacitor is represented by the following equation. Here, C is the capacitance of the capacitor.

W = C · (V _CH ² −V _CL ² ) / 2 As is apparent from the above equation, if the charging voltage V _CH is increased, the stored energy W increases in proportion to the square of the voltage.
The capacitance C of the capacitor can be reduced accordingly. Further, if this capacitor is connected via a self-extinguishing type semiconductor switch element, and the stored energy of the capacitor is discharged while the self-extinguishing type semiconductor switch element is turned on / off in a no-voltage section of the overhead line, the capacitor is connected to an inverter. Is a value corresponding to the conductivity of the self-extinguishing type semiconductor switch element. Therefore, the charging voltage of this capacitor is not a voltage that can be allowed for each element constituting the inverter, but is an allowable voltage for this capacitor. Since the voltage can be increased, the charging voltage can be further increased to further reduce the capacitance of the capacitor. There is a filter capacitor on the input side of the inverter, and there is a possibility that the filter capacitor voltage may rise abnormally due to the energy stored in the inductance of the circuit, but by connecting the filter capacitor and the capacitor via a diode, The filter capacitor voltage can be suppressed to the capacitor voltage.

[0010]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, showing an AC electric vehicle. In FIG. 1, high-voltage AC power from an overhead line 2 is taken into an electric vehicle by a pantograph 3, depressurized by an input transformer 4, and then discharged to the ground via wheels 5 and rails 6. The reduced AC is converted to DC by a rectifier 11 provided on the secondary side of the input transformer 4, and a ripple component is removed by a filter reactor 13 and a filter capacitor 14.
The AC power is converted into an AC having a desired voltage and frequency, and the AC power is supplied to a load in the AC electric vehicle. A voltage detector 21 for detecting the presence or absence of a voltage on the overhead wire 2 is connected to the input transformer 4.
Connect to the secondary side of.

In the circuit of the first embodiment shown in FIG. 1, a charging rectifier 25 as first charging means receives AC power output from the inverter 15 via a charging transformer 26,
The DC output of the charging rectifier 25 charges the capacitor 24 via the smoothing reactor 23. When the thyristor switch 22 serving as a switch element is turned on, the circuit configuration is such that the charging power of the capacitor 24 can be supplied to the inverter 15. Here, when the traveling electric vehicle enters the no-voltage section dividing the overhead wire 2, the voltage detector 21 detects the no-voltage of the overhead wire 2 and issues a command to turn on the thyristor switch 22. When the thyristor switch 22 is turned on, the capacitor 24 supplies the stored energy to the inverter 15 instead of the rectifier 11.
Since the inverter 15 can continue driving as it is, no power failure occurs in the electric vehicle.

When the electric vehicle passes through the no-voltage section of the overhead line 2 and reenters the power application section, the voltage detector 21 detects the presence of a voltage and turns off the thyristor switch 22 that has been on. The charge rectifier 25 continues charging to recover the lowered voltage of the capacitor 24. However, since the charging only needs to be completed before entering the next no-voltage section, the charging period is equal to the discharging time of the capacitor 24. It can be much longer. Therefore, the charging rectifier 25 and the charging transformer 26 need only have a small capacity,
After charging is completed, the leakage current of the capacitor 24 may be supplemented. Therefore, the increase in the output of inverter 15 for this charging is small. Since the charging voltage of the capacitor 24 can be determined independently of the voltage of the DC circuit to which the capacitor 24 is connected, the capacitance of the capacitor 24 can be reduced by charging the capacitor 24 as high as possible as described above. . Therefore, in the case of the circuit of the first embodiment, it is possible to increase the charging voltage of the capacitor 24 to the allowable voltage of the elements constituting the rectifier 11 and the inverter 15.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention. This second embodiment circuit is a self-extinguishing type semiconductor switch instead of the thyristor switch 22 in the first embodiment circuit. The difference is that a GTO (gate turn-off) thyristor 32 is used as an element, and all other points are the same as those of the first embodiment.
A detailed description of the circuit of the second embodiment will be omitted. This second
Even in the circuit of the embodiment, when the voltage detector 21 detects that the electric car has entered the no-voltage section of the overhead line 2, the GTO thyristor 32 is instructed to start operation. This operation turns on and off at a constant rate, and this operation converts the energy stored in the capacitor 24 into a voltage suitable for the inverter 15. Therefore, in the circuit of the second embodiment, the charging voltage of the capacitor 24 can exceed the allowable voltage of the components of the rectifier 11 and the inverter 15 and can be increased to an allowable voltage for the capacitor 24. Can be stored even if is further reduced.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention. The circuit of the third embodiment is the same as that of the first embodiment shown in FIG.
4 is connected via a freewheel diode 50 in a point different from the circuit of the first embodiment. With such a circuit configuration, if the voltage of the filter capacitor 14 becomes higher than the voltage of the capacitor 24 due to the energy stored in the inductance of the filter reactor 13 or a circuit (not shown), the freewheel diode 50 becomes conductive. Thus, the voltage is suppressed to the voltage of the capacitor 24.

FIG . 4 is a circuit diagram showing a fourth embodiment of the present invention.
However, the circuit of the fourth embodiment is the same as that of the second embodiment described with reference to FIG.
Filter capacitor 14 and capacitor 2 in example circuit
4 through a freewheel diode 50
This is different from the circuit of the second embodiment. FIG.
FIG. 9 is a circuit diagram showing a fifth embodiment of the present invention.
The circuit of the embodiment includes the filter capacitor 14 and the capacitor 2
4 through a freewheel diode 50
I have. FIG. 6 is a circuit diagram showing a sixth embodiment of the present invention.
However, the circuit according to the sixth embodiment includes a filter capacitor 14
Capacitor 24 and freewheel diode 50
Connected.

The circuit of the fourth embodiment and the circuit of the fifth embodiment
And the circuit of the sixth embodiment is also the circuit of the third embodiment.
In the same way as in
The voltage of the capacitor 14 is higher than the voltage of the capacitor 24
It suppresses the increase.

[0017]

As described above, the auxiliary power supply device for the electric vehicle replaces the conventional MG system with a stationary type device mainly composed of an inverter so that it is light in weight and can save the trouble of maintenance and inspection. Since there is no flywheel effect as in the MG system, a power failure occurs when passing through a no-voltage section of the overhead line, especially in an AC electrified section, or a large-capacity capacitor is connected to the input side of the inverter to avoid a power failure. However, according to the present invention, a series circuit of an energy storage capacitor and a switch element is installed on the DC input side of the inverter, and the electric vehicle enters the no-voltage section of the overhead line. When it is detected that the power is turned off, the switch element is turned on to supply the stored energy of the capacitor to the inverter to avoid a power failure, but the charging voltage of the capacitor is not equal to the circuit voltage. Because can charge to a higher value in engagement, miniaturization of the device is able to accumulate a large amount of power in small capacitor can be reduced. Further, if the switch element connected in series to the capacitor is replaced with a self-extinguishing type semiconductor switching element such as a GTO thyristor, and the self-extinguishing type semiconductor switching element is turned on and off with an appropriate conductivity, a high charge of the capacitor can be obtained. Since the voltage can be reduced to a desired voltage and supplied, the charging voltage of the capacitor can be further increased, and the capacitance of the capacitor can be further reduced.
In addition, the charging time of the first charging means using the AC output from the inverter as a power source or the second charging means using the DC input side of the inverter as a power source is much longer than the discharging time. Since it may be long, the capacity of these charging means can be reduced. Furthermore, when charging the capacitor using the AC output from the inverter as a power supply, there is no influence of lightning surge or switching surge invading from the overhead line, so there is no need to increase the number of series capacitors in order to improve the withstand voltage characteristics. This has the effect of reducing the size of the device. On the other hand, when the capacitor is charged using the DC input side of the inverter as a power supply, the effect is obtained that all the output of the inverter can be used for in-vehicle power.

Further, by connecting the filter capacitor provided on the inverter input side and the above-mentioned capacitor via a freewheel diode, the filter capacitor voltage becomes abnormal due to the inductance in the circuit and the energy stored in the filter reactor. As a result, it is possible to prevent the device from stopping due to overvoltage applied to the filter capacitor and the inverter.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention.

FIG. 2 is a circuit diagram showing a second embodiment of the present invention.

FIG. 3 is a circuit diagram showing a third embodiment of the present invention.

FIG. 4 is a circuit diagram showing a fourth embodiment of the present invention.

FIG. 5 is a circuit diagram showing a fifth embodiment of the present invention.

FIG. 6 is a circuit diagram showing a sixth embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 2 overhead wire 3 pantograph 4 input transformer 11 rectifier 15 inverter 21 voltage detector 22 thyristor switch as switching element 23 smoothing reactor 24 capacitor 25 charging rectifier as first charging means 26 charging transformer 32 as self-extinguishing semiconductor switch element GTO
Thyristor 41 Chopper as second charging means 50 Freewheel diode

Claims (6)

(57) [Claims] 1. An electric vehicle auxiliary power supply for supplying electric power for a vehicle running inside a vehicle, wherein the electric vehicle supplies either DC taken from an overhead line or rectified DC obtained from an overhead line. An inverter that outputs an AC having a desired voltage and frequency, a voltage detecting unit that detects the presence or absence of an overhead wire voltage, a capacitor that is connected to a DC input side of the inverter via a switch element, and an AC that the inverter outputs. And a first charging means for charging the capacitor by using the power supply as a power source, and normally charging the capacitor to a desired voltage in a state where the switch element is turned off, and the voltage detecting means detects no voltage of the overhead wire, A circuit for preventing an instantaneous power failure of an auxiliary power supply for an electric vehicle, characterized by turning on a switch element. 2. An auxiliary electric power supply for an electric vehicle for supplying electric power in a vehicle to a running electric vehicle, wherein the electric vehicle supplies either DC taken from an overhead wire or DC rectified from AC taken from the overhead wire. An inverter that outputs an AC having a desired voltage and frequency, voltage detecting means for detecting the presence or absence of an overhead wire voltage, a capacitor connected to a DC input side of the inverter via a self-extinguishing semiconductor switch element, First charging means for charging the capacitor using an alternating current output from the inverter as a power supply, wherein the capacitor is charged to a desired voltage in a state where the self-extinguishing semiconductor switch element is normally off, An electric vehicle characterized in that the on / off control of the self-extinguishing type semiconductor switch element at a desired conductivity is performed when a voltage is detected in the overhead wire. 3. An auxiliary electric power supply for an electric vehicle for supplying electric power in a vehicle to a running electric vehicle, wherein the electric vehicle supplies either a direct current taken from an overhead wire or a rectified direct current of an alternating current taken from the overhead wire. An inverter having a smoothing filter capacitor on its input side to output an AC having a desired voltage and frequency;
Voltage detecting means for detecting the presence or absence of an overhead wire voltage, a capacitor connected to a DC input side of the inverter via a switch element, and first charging means for charging the capacitor using the AC output from the inverter as a power supply; A circuit for connecting the filter capacitor and the capacitor via a diode, and always charging the capacitor to a desired voltage in a state where the switch element is turned off, and the voltage detecting means detects no voltage of the overhead wire. An instantaneous power failure prevention circuit for an auxiliary power supply for an electric vehicle, wherein the switch element is turned on. 4. An electric vehicle auxiliary power supply for supplying in-vehicle electric power to a running electric vehicle, wherein the electric vehicle supplies either DC taken from an overhead line or rectified DC obtained from an overhead line. An inverter having a smoothing filter capacitor on its input side to output an AC having a desired voltage and frequency;
Voltage detecting means for detecting the presence or absence of an overhead wire voltage, a capacitor connected to the DC input side of the inverter via a self-extinguishing type semiconductor switch element, and a capacitor for charging the capacitor using the AC output from the inverter as a power supply. (1) a charging means, and a circuit for connecting the filter capacitor and the capacitor via a diode, wherein the capacitor is charged to a desired voltage in a state where the self-extinguishing semiconductor switch element is normally off, and the voltage detection An instantaneous power failure prevention circuit for an auxiliary power supply for an electric vehicle, characterized in that if the means detects no voltage on the overhead line, the self-extinguishing type semiconductor switch element is turned on / off at a desired conductivity. 5. An electric vehicle auxiliary power supply device for supplying electric power for a running electric vehicle to a vehicle, wherein the electric vehicle supplies either DC taken from an overhead line or rectified DC obtained from an overhead line. An inverter having a smoothing filter capacitor on its input side to output an AC having a desired voltage and frequency;
Voltage detecting means for detecting the presence or absence of an overhead wire voltage, a capacitor connected to the DC input side of the inverter via a switch element, and second charging means for charging the capacitor using the DC input side of the inverter as a power supply; A circuit for connecting the filter capacitor and the capacitor via a diode, and always charging the capacitor to a desired voltage in a state where the switch element is turned off, and the voltage detecting means detects no voltage of the overhead wire. An instantaneous power failure prevention circuit for an auxiliary power supply for an electric vehicle, wherein the switch element is turned on. 6. An auxiliary electric power supply for an electric vehicle for supplying electric power in a vehicle to a running electric vehicle, wherein the electric vehicle supplies either direct current taken from an overhead wire or direct current obtained by rectifying alternating current taken from the overhead wire. An inverter having a smoothing filter capacitor on its input side to output an AC having a desired voltage and frequency;
Voltage detecting means for detecting the presence or absence of an overhead wire voltage; a capacitor connected to the DC input side of the inverter via a self-extinguishing type semiconductor switch element; and (2) charging means, and a circuit for connecting the filter capacitor and the capacitor via a diode, the capacitor being charged to a desired voltage in a state where the self-extinguishing type semiconductor switch element is normally turned off, and An instantaneous power failure prevention circuit for an auxiliary power supply for an electric vehicle, characterized in that if the means detects no voltage on the overhead line, the self-extinguishing type semiconductor switch element is turned on / off at a desired conductivity.