JPH1198610A - Controller for alternating current electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an AC electric vehicle controller which is capable of preventing an excessive charging current from being supplied at the time of charging a capacitor, without providing a special apparatus for charging the capacitor. SOLUTION: This apparatus has a contactor 4 connected to the secondary winding of a transformer 3, a converter 5 for converting an alternating current to be supplied via the transformer 3 into a direct current, a capacitor 6 connected to the output end of this converter 5, an inverter 7 for converting a direct current converted by the converter 5 into an alternating current, connected to both the ends of this capacitor 6. and a controller 23 which makes the contactor 4 at the time of starting, rectifies an alternating current to be supplied by the rectifying devices 51-54 of the converter 5 through the transformer 3 into a direct current and charges the capacitor 6, and fires self-arc extinguishing type devices 57, 58 of the converter 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC electric vehicle control device.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram of a conventional AC electric vehicle control device. AC power collected from the overhead wire 1 via the pantograph 2 is supplied to the converter 5 via the contactor 4 connected to the secondary winding of the transformer 3. Converter 5
Converts AC power into DC power and supplies DC power to an inverter 7 connected via a capacitor 6. Then, the inverter 7 converts DC power to AC power and drives the induction motor 8.

By the way, in the AC electric vehicle control device configured as described above, it is necessary to charge the capacitor 6 to a desired voltage at the time of starting. When charging the capacitor 6, it is necessary to take care that an excessive charging current is not supplied.

[0004]

Therefore, in the conventional AC electric vehicle control device, an auxiliary circuit comprising a series circuit of a resistor 9 and a charging contactor 10 and a short-circuit contactor 11 for short-circuiting the series circuit is provided in parallel. A circuit is provided on the input side of the converter 5, and at the time of startup, the charging contactor 10 is turned on, and the pantograph 2,
The AC power from the transformer 3 and the contactor 4 is supplied to the converter 5 via the resistor 9 and the capacitor 6 is charged, thereby preventing an excessive charging current from being supplied. When the capacitor 6 is charged to a desired voltage, the short circuit contactor 11 is turned on to short-circuit the series circuit.

However, various control devices for controlling the electric vehicle must be mounted in a limited space below the floor of the electric vehicle. However, if a parallel circuit for charging the capacitor 6 is provided, a corresponding amount of the control device is required. This leads to an increase in the weight and volume of the device.

SUMMARY OF THE INVENTION It is an object of the present invention to provide an AC electric vehicle control device that prevents an excessive charging current from being supplied during charging of a capacitor without providing a special device for charging the capacitor. I do.

[0007]

In order to achieve the above-mentioned object, an invention according to claim 1 comprises a contactor connected to a secondary winding of a transformer and a plurality of contactors connected to the contactor. A bridge circuit composed of rectifying elements, a self-extinguishing type element connected in anti-parallel to each rectifying element, and a converter for converting alternating current supplied through the transformer to direct current,
A capacitor connected to the output end of the converter, an inverter connected to both ends of the capacitor, which converts the direct current converted by the converter into an alternating current, and, at start-up, the contactor is turned on, and the rectifying element turns on the contactor. A controller for rectifying the alternating current supplied through the transformer to direct current to charge the capacitor, and when the capacitor is charged to a predetermined value, firing the self-extinguishing element. Become.

According to a second aspect of the present invention, in the first aspect of the present invention, the control device turns on the contactor while the phase of the AC voltage input to the converter is between π / 2 and π. It is characterized by doing.

According to a third aspect of the present invention, in the first aspect of the invention, the control device includes a zero-crossing determination circuit for detecting a zero-crossing point of the AC voltage input to the converter, and the zero-crossing determination circuit. A delay circuit for turning on the contactor with a predetermined delay from the detected zero cross point.

According to a fourth aspect of the present invention, in the first aspect of the present invention, the control device determines that the maximum value of the charging voltage of the capacitor reached when the self-extinguishing element is not fired is the minimum. The contactor is turned on at a phase of an AC voltage input to the converter as described above.

According to a fifth aspect of the present invention, in the first aspect of the present invention, when the capacitor is charged to a predetermined value, the control device activates the self-extinguishing element constituting the lower arm. It is characterized by firing.

According to a sixth aspect of the present invention, there is provided a contactor connected to a secondary winding of a transformer and a bridge circuit connected to the contactor and comprising a plurality of rectifiers. Is a self-extinguishing element connected in anti-parallel, a converter for converting alternating current supplied through the transformer to direct current, a capacitor connected to an output terminal of the converter, and a capacitor connected to both ends of the capacitor. An inverter connected to convert the DC converted by the converter into an AC;
At the time of start-up, the contactor is turned on, a charge mode in which the rectifying element rectifies an alternating current supplied through the transformer to a direct current to charge the capacitor, and the self-extinguishing element is ignited. And a control device for repeating a discharge mode for discharging the capacitor.

[0013]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram of an AC electric vehicle control device according to an embodiment of the present invention, and FIG.
Is a time chart of various state quantities.

AC power collected from the overhead line 1 via the pantograph 2 is supplied to the converter 5 via the contactor 4 connected to the secondary winding of the transformer 3. Where 31
Is the leakage reactance of the transformer 3. Converter 5 converts AC power into DC power and supplies DC power to inverter 7 connected via capacitor 6. Then, the inverter 7 converts DC power to AC power and drives the induction motor 8. Converter 5 includes diodes 51 to 54
The self-extinguishing type elements 55 to 58 are connected in anti-parallel to the respective bridge circuits. The AC voltage Vs generated on the secondary winding side of the transformer 3 and the voltage Vd between the terminals of the capacitor 6 are detected by voltage detectors 20 and 21, respectively.
s is detected by the current detector 22 and input to the control device 23. Then, the control device 23 turns on the contactor 4,
The converter 5 is controlled.

The control device 23 inputs the AC voltage Vs detected by the voltage detector 20, and outputs a closing command K for turning on the contactor 4 according to the value of the AC voltage Vs. The contactor 4 is closed in response to the closing command K. Then, the current Is flows through the path of the diode 51 → the capacitor 6 → the diode 54, and the capacitor 6 is charged. The control device 23 inputs the voltage Vd between the terminals of the capacitor 6 detected by the voltage detector 21, and switches the self-extinguishing elements 57 and 58 when the voltage Vd between the terminals reaches a predetermined value. Is output. The self-extinguishing elements 57 and 58 are fired in response to the switching command Sw. Then, the current Is flowing through the path from the diode 51 → the capacitor 6 → the diode 54 becomes the diode 5
1 commutates to the self-extinguishing element 57, and returns to the secondary winding side of the transformer 3 via the diode 54. At this time, the capacitor 6 is not charged. The polarity of the AC voltage Vs eventually reverses, the value of the current Is also starts to decrease, and when the current Is detected by the current detector 22 becomes zero, the control device 2
Reference numeral 3 outputs a switching command Sw for extinguishing the self-extinguishing elements 57 and 58. The self-extinguishing elements 57 and 58 are extinguished in response to the switching command Sw. After that,
Control for driving the ordinary induction motor 8 may be performed by the converter 5 and the inverter 7.

As described above, the contactor 4 and the converter 5 are controlled by the control device 23 at the time of startup when charging of the capacitor 6 is required, so that overcharging of the capacitor 6 can be prevented. Note that the arc extinguishing of the self-extinguishing elements 57 and 58
The control is performed so that the current is reduced when s becomes zero. However, if the current Is is reduced to a level that does not cause a problem even if the charging voltage of the capacitor 6 is increased, even if the current Is is not zero, The self-extinguishing elements 57 and 58 may be extinguished.

Next, the timing of turning on the contactor 4 by the control device 23 will be described. FIG. 3 is a time chart of various state quantities depending on the difference in the closing timing of the contactor 4. FIG. 3 (i) shows a case where the contactor 4 is turned on from the rise of the AC voltage Vs, and the current Is and the inter-terminal voltage Vd change as shown by a solid line. On the other hand, (ii) is a case where the contactor 4 is turned on when the phase of the AC voltage Vs is between π / 2 and π,
The current Is and the inter-terminal voltage Vd change as shown by a dotted line. In (i), the terminal voltage Vd reaches the predetermined value quickly, but the current Is increases. On the other hand, in (ii), the current Is can be kept low. Therefore, the closing timing of the contactor 4 is (ii) rather than (i).
Can prevent overcurrent to the capacitor 6.

FIG. 4 is a block diagram of the closing control section of the contactor 4 of the control device 23. The AC voltage Vs detected by the voltage detector 20 is input to a zero-crossing determination circuit 231, where a zero point is detected, and the delay circuit 232 delays the contactor a predetermined time after the zero-crossing point of the AC voltage Vs. 4 is output. The contactor 4 is turned on in response to the input command K, and the time error required for turning on the contactor 4 is preferably several ms. By performing such control, it is possible to prevent the contactor 4 from being turned on from the rise of the AC voltage Vs, and to prevent an overcurrent to the capacitor 6. Further, specifically, assuming that the inductance of the leakage reactance 31 is L,

[0019]

Vs−Vd = L · (dIs / dt) C · (dVd / dt) = Is, and the maximum value Vdmax of the terminal-to-terminal voltage Vd (the self-extinguishing elements 57 and 58 are fired) Control device 23 so that the contactor 4 is turned on at a phase θ such that
Can be controlled.

FIG. 5 is a diagram for explaining another embodiment of the present invention, and is a configuration diagram of a main part of an AC electric vehicle control device. In the present embodiment, when the contactor 4 is turned on according to the value of the AC voltage Vs, a current flows through the path A from the diode 51 → the capacitor 6 → the diode 54, and the capacitor 6 is charged. Here, when the self-extinguishing elements 56 and 57 are ignited, the capacitor 6 is discharged through the path B of the self-extinguishing element 57 → the capacitor 6 → the self-extinguishing element 56.
When the self-extinguishing elements 56 and 57 are extinguished, the path A
, A current flows and charging of the capacitor 6 is restarted. By controlling the self-extinguishing elements 56 and 57 in this way and repeating charging and discharging of the capacitor 6, overcharging and overcurrent of the capacitor 6 can be prevented.

In each of the embodiments, the case where the contactor 4 is turned on to charge the capacitor 6 when the AC voltage Vs has a positive polarity has been described.
Is applied, since the path of the charging current of the capacitor 6 changes, the same control may be performed by changing the self-extinguishing element that is fired in order to end charging each time.

[0022]

As described above, according to the present invention, an AC electric vehicle control device for preventing an excessive charging current from being supplied during charging of a capacitor without providing a special device for charging the capacitor. Can be provided.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an AC electric vehicle control device showing an embodiment of the present invention.

FIG. 2 is a time chart.

FIG. 3 is a time chart.

FIG. 4 is a configuration diagram of a contact control unit of the contactor.

FIG. 5 is a main part configuration diagram of an AC electric vehicle control device showing another embodiment of the present invention.

FIG. 6 is a configuration diagram of a conventional AC electric vehicle control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Overhead wire 2 ... Pantograph 3 ... Transformer 4 ... Contactor 5 ... Converter 51,52,53,54 ... Diode 55,56,57,58 ... Self-extinguishing element 6 ... Capacitor 7 ... Inverter 8 ... Induction motor 20 , 21 ... Voltage detector 22 ... Current detector 23 ... Control device 231 ... Zero crossing determination circuit 232 ... Delay circuit

Claims (6)

[Claims] 1. A contactor connected to a secondary winding of a transformer, and a bridge circuit comprising a plurality of rectifiers connected to the contactor, wherein each rectifier is self-extinguishing in antiparallel. A converter for converting AC supplied through the transformer into DC, a capacitor connected to an output terminal of the converter, and a capacitor connected to both ends of the capacitor, and converted by the converter. An inverter that converts the direct current into an alternating current, and at the time of start-up, the contactor is turned on, the alternating current supplied through the transformer by the rectifying element is rectified into direct current, and the capacitor is charged. A control device for igniting the self-extinguishing element when charged to a predetermined value. 2. The AC electric vehicle control device according to claim 1, wherein the control device turns on the contactor while the phase of the AC voltage input to the converter is between π / 2 and π. Characteristic AC electric vehicle control device. 3. The AC electric vehicle control device according to claim 1, wherein the control device detects a zero cross point of an AC voltage input to the converter, and the control device detects the zero cross point. An AC electric vehicle control device, comprising: a delay circuit for turning on the contactor at a predetermined delay from the zero crossing point. 4. The AC electric vehicle control device according to claim 1, wherein the control device is configured to minimize a maximum value of a charging voltage of the capacitor that is reached when the self-extinguishing element is not fired. An AC electric vehicle control device, wherein the contactor is turned on at a phase of an AC voltage input to the converter. 5. The AC electric vehicle control device according to claim 1, wherein the control device fires the self-extinguishing element constituting the lower arm when the capacitor is charged to a predetermined value. An AC electric vehicle control device, characterized in that: 6. A contactor connected to a secondary winding of a transformer, and a bridge circuit comprising a plurality of rectifying elements connected to the contactor, wherein each rectifying element is self-extinguishing in antiparallel. A converter for converting AC supplied through the transformer into DC, a capacitor connected to an output terminal of the converter, and a capacitor connected to both ends of the capacitor, and converted by the converter. An inverter that converts the direct current into an alternating current, and a charging mode in which, at startup, the contactor is turned on, and the rectifying element rectifies the alternating current supplied through the transformer to direct current to charge the capacitor. A control device that repeats a discharge mode in which the self-extinguishing element is ignited to discharge the capacitor.