JPH07115777A - Auxiliary power supply for vehicle - Google Patents

Abstract

(57) [Abstract] [Purpose] To prevent the DC intermediate circuit voltage from fluctuating even when the load current changes, and to prevent the inverter connected to the DC intermediate circuit from becoming large. [Structure] A phase-controllable semiconductor switch element such as a thyristor switch 21 is connected in parallel to the charging resistor 16. The deviation between the voltage of the smoothing capacitor 14 detected by the capacitor voltage detector 22 and the voltage command value set by the capacitor voltage detector 22 is input to the voltage regulator 24, and a control signal for making the input deviation zero is input to the voltage regulator. Take out from 24. The phase shifter 26 controls the ignition phase of the thyristor switch 21 in accordance with this control signal, so that even if the vehicle auxiliary power supply device 10 becomes a light load and the DC intermediate circuit current becomes intermittent, the smoothing capacitor 14 Suppresses the DC intermediate circuit voltage from rising due to peak value charging.

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 device for a vehicle, which is mounted on a vehicle, rectifies an input alternating current with a diode, smoothes it with a reactor and a capacitor, and converts this smoothed direct current into an alternating current with an inverter.

[0002]

2. Description of the Related Art FIG. 2 is a circuit diagram showing a general example of a power system of an AC electric vehicle. As shown in FIG. 2, in the AC electric vehicle, the AC power supplied by the overhead line 2 is supplied to the pantograph 3
After being taken into the vehicle via the primary winding 4A of the transformer 4 and then discharged to the rail 6 via the wheels 5. Transformer 4
The AC power extracted from the secondary winding 4B by being insulated and transformed is converted into AC power having a variable voltage and a variable frequency by the VVVF inverter 7, and the induction motor 8 is driven at a variable speed.
Since the induction motor 8 is connected to the wheel 5 described above,
The AC electric vehicle can be driven at a desired speed.
Alternatively, although not shown, the transformer 4 may be insulated / transformed to convert the AC power extracted from the secondary winding 4B into DC, and this DC power drives a DC motor coupled to the wheels 5. Thus, the AC electric vehicle can be driven at a desired speed. However, since each of these devices that drive the AC electric vehicle is irrelevant to the present invention, description of this part is omitted.

Lighting, communication, air conditioners, etc. are mounted on an AC electric vehicle, but these devices generally operate by AC. Further, in order to control the AC electric vehicle, high-quality AC power with stable voltage and frequency is required as a control power supply. Therefore, the transformer 4 described above is connected to the tertiary winding 4C.
Is provided, and the AC power extracted from the tertiary winding 4C is
After being converted into high-quality AC power by the vehicle auxiliary power supply device 10, it is generally supplied to the vehicle interior load 9 described above.

FIG. 3 is a circuit diagram showing a conventional example of the configuration of the vehicle auxiliary power supply device 10 shown in the power system circuit diagram of the AC electric vehicle of FIG. As shown in FIG. 3, the diode rectifier 12 inputs the AC power insulated and transformed by the transformer tertiary winding 4C described above through the power switch 11, and converts the AC power into DC power. , To the DC intermediate circuit connecting the DC side of the diode rectifier 12 and the DC side of the inverter 15. Since a smoothing reactor 13 and a smoothing capacitor 14 are installed in this DC intermediate circuit to absorb and remove the ripple component contained in the DC power output by the diode rectifier 12, the smoothed DC power is sent to the inverter 15. Can be given. The inverter 15 converts the input DC power into AC power of a predetermined voltage and frequency and supplies the AC power to the in-vehicle load 9.

When the vehicle auxiliary power supply 10 is started, the power switch 11 is first closed, but an excessive charging current rushes into the smoothing capacitor 14 at the moment when the power switch 11 is closed. Since the AC electric vehicle takes in single-phase AC power from the overhead line 2, the diode rectifier 12 is configured by a single-phase bridge connection. The DC power obtained by full-wave rectification by the single-phase bridge-connected diode rectifier 12 contains a large amount of ripples (half-wave rectification increases the ripples), so this ripple is absorbed.
In order to remove it, it is necessary to connect a large-capacity smoothing capacitor 14 to the DC intermediate circuit, and as a result, the above-mentioned charging current that rushes at the time of start-up becomes even larger.

Therefore, the charging resistor 16 is connected to the smoothing reactor 13
Is connected in series with the power switch 11 to prevent the charging current from entering when the power switch 11 is closed. However, when the vehicle auxiliary power supply device 10 is operated with the charging resistor 16 connected in series, the charging resistor 16 is always
Current flows into the device, causing loss, so smoothing capacitor 1
When the charging of 4 is completed, the short-circuit switch 17 connected in parallel to the charging resistor 16 is closed to short-circuit the charging resistor 16.
Prevent loss.

[0007]

FIG. 4 is a waveform diagram showing changes in the output voltage and the output current of the diode rectifier 12 shown in FIG. 3, and FIG.
2 shows the output voltage waveform of FIG. 2, and FIG. 4 shows the output current waveform of the diode rectifier 12. As previously mentioned,
Since the diode rectifier 12 is a single-phase bridge connection,
The voltage waveform when the input AC is full-wave rectified is A. At this time, the average value of the DC intermediate circuit voltage (that is, the terminal voltage of the smoothing capacitor 14) is a straight line B shown by the broken line in FIG. 4, which is about 90% of the AC input voltage effective value and about the AC input voltage peak value. 64%. When the current flowing through the smoothing reactor 13 (that is, the output current of the diode rectifier 12) is continuous as shown in the curve C of FIG.
However, when the load becomes light and the current of the smoothing reactor 13 becomes an intermittent state (curve D in FIG. 4), the smoothing capacitor 14 has the peak value of the waveform shown in FIG. 4A. Will be charged. That is, assuming that the terminal voltage of the smoothing capacitor 14 is V ₁₄ and the effective voltage value of the AC power source is V _AC , the relationship between the two is as shown in the following mathematical formula 1.

[0008]

[Formula 1] V ₁₄ > 0.9 · V _AC Furthermore, the relationship between the terminal voltage V ₁₄ of the smoothing capacitor ₁₄ and the AC power supply voltage effective value V _AC when the diode rectifier 12 is completely unloaded is the following Expression 2. .

[0009]

[Number 2] V ₁₄ = 1.414 · V _AC which means that the variation range of the DC intermediate circuit voltage (i.e. the input voltage of the inverter 15) is large. Therefore, the inverter 15 has to cope with such a large input voltage fluctuation so as to operate normally (for example, allow a margin in the withstand voltage of the semiconductor switch element). It has the drawback of being expensive.

Therefore, an object of the present invention is to prevent the DC intermediate circuit voltage from fluctuating even if the load current changes so as to prevent the inverter connected to the DC intermediate circuit from becoming large.

[0011]

In order to achieve the above object, an auxiliary power supply device for a vehicle of the present invention comprises a diode rectifier for converting a single-phase alternating current into a direct current by using a diode,
A smoothing reactor and a smoothing capacitor that remove the ripple component included in the direct current output by this diode rectifier, an inverter that converts this smoothed direct current into an alternating current, and a smoothing reactor connected in series to the smoothing reactor. In a vehicle auxiliary power supply device including a charging resistor that suppresses a charging current and a short-circuiting device that short-circuits the charging resistor, a semiconductor switch element capable of phase control is used for the short-circuiting device. Phase control means for controlling the voltage of the smoothing capacitor, voltage detecting means for detecting the voltage of the smoothing capacitor, and voltage adjusting means for outputting to the phase control means a control signal for matching the smoothed capacitor voltage detected value with a preset voltage command value. And are provided.

[0012]

In the DC intermediate circuit connecting the DC side of the diode rectifier and the DC side of the inverter, a smoothing reactor and a smoothing capacitor for absorbing and removing the ripple component contained in the DC output from the diode rectifier are provided. , Equipped with a charging resistor that suppresses the charging current of this smoothing capacitor, and a short-circuit switch that short-circuits this charging resistor,
In the present invention, a semiconductor switch element capable of controlling a phase (for example, a thyristor, a GTO thyristor, etc.) is used as the short-circuiting switch, and a capacitor voltage detecting means for detecting the terminal voltage of the smoothing capacitor and a smoothing capacitor voltage are set to a predetermined voltage. A voltage adjusting means for maintaining a command value, and a phase shifting means for controlling the ignition phase of the semiconductor switch element according to a control signal output by the voltage adjusting means,
Even if the DC intermediate circuit current decreases and becomes an intermittent state, and the smoothing capacitor voltage tries to rise due to peak value charging, the phase adjustment of the semiconductor switch element is performed by the action of these voltage adjusting means and phase shifting means, and the smoothing capacitor voltage is increased. Can be maintained at the voltage command value to prevent the DC intermediate circuit voltage from rising.

[0013]

FIG. 1 is a circuit diagram showing an embodiment of the present invention. The power switch 11 shown in the embodiment circuit of FIG.
Since the names, applications, and functions of the diode rectifier 12, the smoothing reactor 13, the smoothing capacitor 14, and the inverter 15 are the same as in the case of the conventional circuit described above with reference to FIG.
These explanations are omitted.

In the present invention, a semiconductor switch element capable of phase control is used as a short-circuiting means for short-circuiting the charging resistor 16 inserted in the DC intermediate circuit in order to suppress the charging current of the smoothing capacitor 14. The thyristor switch 21 is used as the semiconductor switch element, for example. Further, a capacitor voltage detector 22 for detecting the voltage V ₁₄ of the smoothing capacitor 14 is connected. When a deviation between the voltage V _{14 of the} smoothing capacitor 14 detected by the capacitor voltage detector 22 and the voltage command value set by the voltage setter 23 is given to the voltage regulator 24, the voltage regulator 24 controls the input deviation to be zero. Output a signal.
The phase shifter 26 is configured to receive this control signal and the AC side voltage phase signal detected by the AC voltage detector 25 and send an ignition signal of an appropriate phase to the gate of the thyristor switch 21.

Similar to the conventional circuit of FIG. 3, when the power switch 11 is closed to activate the vehicle auxiliary power supply device 10, the thyristor switch 21 is off, so that the charging current to the smoothing capacitor 14 is charged by the charging resistor. It is suppressed at 16. When charging in this state is completed, the thyristor switch 21 is turned on to charge the smoothing capacitor 14 to a predetermined voltage, and the vehicle auxiliary power supply device 10 can start operation. If the load current decreases and the DC intermediate circuit current becomes intermittent while the vehicle auxiliary power supply 10 is in operation, the smoothing capacitor 14 will be charged at the peak value, but the capacitor voltage detector 22 will always Voltage V
₁₄ is monitored and the voltage regulator 24 and the phase shifter 26 control the firing phase of the thyristor switch 21 so as to match the voltage command value set by the voltage setter 23.
The smoothing capacitor 14 voltage V ₁₄ can be suppressed from rising. The AC voltage detector 25 is connected to the AC side of the diode rectifier 12 and is used to obtain a synchronizing signal.

As a semiconductor switch element which is connected in parallel to the charging resistor 16 and serves as a short-circuiting means, a GTO thyristor or the like can be used instead of the thyristor switch 21.

[0017]

According to the present invention, the resistance short-circuit means is connected in parallel with the charging resistance for suppressing the charging current of the smoothing capacitor connected to the DC intermediate circuit, but the resistance short-circuit means can control the phase. For example, a thyristor or a GTO thyristor is used as the semiconductor switch element, and the ignition phase of this semiconductor switch element is controlled so that the smoothing capacitor voltage always matches the predetermined voltage command value. By doing so, even if the load of the vehicle auxiliary power supply device is lightened and the DC intermediate circuit current is in an intermittent state, the increase of the DC intermediate circuit voltage due to the smoothing capacitor being charged at the peak value is avoided. Because you can
It is possible to avoid fluctuations in the input voltage of the inverter that constitutes the vehicle auxiliary power supply device. As a result, it is not necessary to give a margin to each element forming the inverter, the effect of reducing the size and weight of the device can be obtained, and the effect of reducing the cost can be obtained together.

[Brief description of drawings]

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

FIG. 2 is a circuit diagram showing a general example of a power system of an AC electric vehicle.

3 is a circuit diagram showing a conventional example of the configuration of a vehicle auxiliary power supply device 10 shown in the power system circuit diagram of the AC electric vehicle of FIG.

FIG. 4 is a waveform diagram showing changes in output voltage and output current of the diode rectifier 12 shown in FIG.

[Explanation of symbols]

4 Transformer 5 Wheel 6 VVVF Inverter 8 Induction Motor 9 Vehicle Load 10 Auxiliary Power Supply Device for Vehicle 11 Power Switch 12 Diode Rectifier 13 Smoothing Reactor 14 Smoothing Capacitor 15 Inverter 16 Charging Resistor 17 Short-Circuit Switch 21 Thyristor Switch as Semiconductor Switch Element 22 Capacitor Voltage detector 23 Voltage setting device 24 Voltage regulator 25 AC voltage detector 26 Phase shifter

Claims (3)

[Claims] 1. A diode rectifier configured by a diode to convert a single-phase alternating current into a direct current, a smoothing reactor and a smoothing capacitor for removing a ripple component contained in a direct current output from the diode rectifier, and the smoothed reactor. A vehicle auxiliary power supply device comprising: an inverter that converts direct current into alternating current; a charging resistor that is connected in series to the smoothing reactor to suppress a charging current to the smoothing capacitor; and a short-circuiting unit that short-circuits the charging resistor. , A phase-controllable semiconductor switch element is used for the short-circuit means, a phase control means for controlling the phase of the semiconductor switch element, a voltage detection means for detecting the voltage of the smoothing capacitor, and a smoothing capacitor voltage detection value. And a voltage adjusting means for outputting a control signal that matches a preset voltage command value to the phase controlling means. An auxiliary power supply device for a vehicle characterized by the above. 2. The vehicle auxiliary power supply device according to claim 1, wherein a thyristor is used as the phase controllable semiconductor switch element. 3. The vehicle auxiliary power supply device according to claim 1, wherein a gate turn-off thyristor is used as the phase-controllable semiconductor switch element.