JPS6271402A - Protective device for drive of electric rolling stock - Google Patents

Abstract

PURPOSE:To decrease the number of operations of reclosing of a breaker by stopping the operation of a controller when both-end voltage of a filter capacitor reaches a first reference value and turning the breaker OFF when the voltage reaches a second reference value while forming a capacitor discharging circuit. CONSTITUTION:A comparator 24 turns a chopper 9 OFF for a fixed time T1 when both-end voltage Vc of a filter capacitor 4 reaches a first reference value. A comparator 21a OFF-operates a high-speed breaker 2 for fixed time T2 while turning a thyristor 5 OFF and discharges the charges of the filter capacitor 4 when voltage Vc reaches a second reference value. Accordingly, the number of operation of reclosing of the hihg-speed breaker can be reduced without lowering protective performance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a protection device for an electric vehicle drive device that protects the electric vehicle drive device from overvoltage.

[Technical pipes of the invention and their problems]

FIG. 3 shows the configuration of the main circuit of a typical electric vehicle drive device. In the figure, a high-speed breaker 2 for cutting off a power supply circuit, a filter reactor 3 for suppressing voltage fluctuations, and a filter capacitor 4 are connected in series in this order between a pantograph 1 as a current collector and a wheel 16 as a ground end. ing. Of these, the filter capacitor 4 includes a thyristor 5 for suppressing both voltages from becoming excessive.
is connected via a resistor 6, and an instrument transformer 7 for detecting the voltage across the terminal is connected via a resistor 8. Further, the filter capacitor 4 is used as a voltage source, and a chopper as a controller and an electric vehicle driving motor 1a10 are connected in series to both ends of the filter capacitor 4 as a voltage source. Note that the electric motor 10 has a field winding 1
1 and an armature winding 12 are connected in series, and a flywheel diode 13 is connected to this, and the field winding 11 is equipped with a chopper 1 for field weakening control.
4 are connected via a resistor 15.

Here, when current is introduced into the vehicle from the pantograph 1, it passes through the filter reactor 3 to the filter capacitor 4.
is charged, producing a relatively stable voltage across it. In this state, when the chopper 9 is operated by a control device (not shown), the Ti flow of the electric motor 10 is controlled and the electric car is driven. In addition, the chopper 14 is controlled by a control device (not shown).
By activating this, field weakening control operation at high speeds becomes possible.

Incidentally, the instrument transformer 7 detects the voltage across the filter converter 4 and uses it to control the electric motor 10, and is also used to protect the filter converter 4, the stopper 9, and the electric motor 10.

FIG. 4 is a schematic configuration diagram of a protection device using a measuring device 7, in which the output signal of the π1 voltage transformer 7 is compared with a reference signal by a comparator 21, and the voltage across the capacitor 4 exceeds the protection level. When this happens, a logic "1" signal is applied to the medium-stable multi-by-break 22. The monostable multivibrator 22 generates a pulse signal that becomes logic "1" for a predetermined period of time from the rise of the input signal and applies it to the gate amplifier circuit 23 and also to the breaker 2. At this time, the gate amplifier circuit 23 fires the thyristor 5.

Thus, when the voltage across the filter capacitor 4 exceeds the protection level, the thyristor 5 is fired by the gate amplifier circuit 23, so that current 2 flows and the charge in the filter capacitor 4 is rapidly released.

Further, due to this discharge, the voltages applied to the filter capacitor 4, chopper 9, and electric motor 110 are lowered, and each of them is protected from overvoltage. In this case, the time for turning on the thyristor 5 can be made sufficiently shorter than the time for the voltage of the filter capacitor 4 to rise sharply, thereby reliably protecting each of the above-mentioned devices from overvoltage.

By the way, when the thyristor 5 is turned on, the short circuit current 11 flows through the pantograph 1, the breaker 2, . . . , the thyristor 5, and the wheels 16.

This short-circuit current 11 must be immediately replaced, and for this purpose, the output of the monostable multivibrator 22 is applied to the high-speed breaker 2 to avoid turning it off.

On the other hand, when the high-speed breaker VSI 2 turns off, it generally requires the driver to turn it on again, but with the above-mentioned conventional protection device, the driver must frequently turn it on again when the high-speed breaker VSI 2 turns off. There wasn't. This will be explained below.

Of the filter converter 4, chopper 9, and electric motor 10 that are to be protected against overvoltage, the chopper 9 generally has the lowest withstand voltage, and its withstand voltage during chopping operation is even lower. Therefore, at present, the protection level must be determined based on the withstand voltage of the chopper 9 during the chopping operation, and this has been a factor in increasing the number of times the high-speed circuit breaker 2 is turned off.

In addition, recently there has been a trend to use pantographs with a simple structure, or in other words, single pantographs, in order to reduce the effort involved in maintaining overhead wires. When a single pantograph is adopted, the frequency of disconnection increases, and accordingly, overvoltage is likely to occur, which increases the number of times the high-speed breaker 2 is turned off, resulting in a 1-prison situation.

Thus, the conventional protection device has a problem in that the number of times the driver has to turn on the high-speed interrupter again increases, which increases the stress on the driver.

(Object of the invention) The present invention was made to solve the above problems.
To provide a protection device for an electric vehicle drive device that can significantly reduce the number of times a high-speed Ii device is re-energized without lowering the protection performance for equipment to be protected, and can significantly reduce the stress on a driver.

[Summary of the invention]

To achieve this objective, the electric vehicle drive device protection device of the present invention includes a switching element connected in parallel to a filter capacitor via a resistance element, and a filter capacitor connected in parallel to the filter capacitor.
a first comparator that compares the output of this voltage detector with a reference value and generates a signal when the voltage across the filter capacitor reaches a first protection level; a second comparator that compares the output of the voltage detector with a reference value and generates a signal when the voltage across the filter capacitor reaches a second protection level higher than the first protection level; The signal from the first comparator stops the operation of the controller, and the signal from the second comparator turns on the Takeki switching element and turns off the shutter wI device.

(Implementation of the invention W4) Fig. 1 is a circuit diagram showing the configuration of an embodiment of the present invention in blocks showing the main parts, and the same reference numerals as in Fig. 4 indicate the same elements. ing. It is also noted that a comparator 21a with a different reference value level is used in place of the converter 21 in FIG.
A comparator 24 outputs a logic "1" signal when the reference value at the same level as the t position is exceeded, and a logic "1" signal is output for a predetermined time from the rise of the output signal of this comparator.
The difference from FIG. 4 is that a monostable multivibrator 25 is newly provided which outputs a signal to be added as an operation stop signal to the chopper 9.

The operation of this embodiment configured as described above will be explained below with reference to the time chart of FIG.

First, the voltage across the filter capacitor 4 is as shown in Fig. 2(a).
When the voltage changes as shown in , a signal corresponding to this voltage is applied to comparators 21a and 24. At this time, the comparator 24 outputs a pick-up voltage PLJI and a dropout voltage DO corresponding to the withstand voltage during the chopping operation of the chopper 9, that is, the first protection level with a low value.
The reference value level is set to have a value of 1. Also,
The reference value level of the comparator 21a is set so as to have a pick-up voltage PU2 and a dropout voltage DO2 corresponding to a second protection level that is larger than the withstand voltage of the chopper 9 while it is stopped, that is, the first protection level.

Therefore, if an overvoltage 31 occurs that is large enough to exceed the second protection level, the comparator 24 is
), the logic is “1” from time t to time t4.
In response to this, the monostable multivibrator 25 outputs a signal of "1" for a time T1 from time t, as shown in FIG. 2(C). Further, the comparator 21a outputs a signal of "1" from time t2 to time t3 as shown in FIG. 2(d),
In response to this, the monostable multivibrator 22 is
As shown in figure (e), it is "1" only from time t to T, 1.
Outputs the signal.

Therefore, the operation of the chopper 9 is stopped for the time period T1 in which both ff1ffi pressures of the filter capacitor 4 exceed the withstand voltage during the chopping operation of the chopper 9, that is, the first protection level, and the chopper 9 is kept in a state with a larger withstand voltage. be done. Also, the voltage of the filter capacitor 4 is
When the voltage exceeds the withstand voltage during stoppage, that is, the second protection level, the high-speed breaker 2 is turned off, and at the same time, the Nyristor 5 is turned on, and the discharge current I2 flows for a time T.sub.2.

Next, if an overvoltage 32 that exceeds the first protection level but does not exceed the second protection level occurs across the filter capacitor 4, the comparator 24
“1” from time t5 to time t6 as shown in Figure (b)
The monostable multivibrator 25 outputs a signal of "1" for a time T1 from time t5. On the other hand, the outputs of the comparator 21a and the monostable multivibrator 22 are held at "0".

Therefore, in response to an overvoltage 32 across the filter capacitor 4 that exceeds the first protection level but does not exceed the second protection level, the operation of the chopper 9 is stopped for a time T1, but the high-speed breaker 2 In the closed state, the thyristor 5 is kept in the off state.

In general, even in situations where wire disconnection occurs frequently due to the adoption of a single pantograph, the LR component of the filter capacitor caused by the l11 wire is often about the overvoltage 32 shown in Figure 2 (a>). On the other hand, in this embodiment, the chopper 9 is configured to stop for a certain period of time and then automatically return, so the number of times the driver has to re-close the high-speed breaker is significantly reduced compared to conventional devices. .

Furthermore, since the chopper 9 is stopped in response to these overvoltages 32 and the withstand voltage is increased, the protection characteristics for the equipment to be protected are reduced. I don't have to.

In the above embodiment, an electric vehicle drive device having a pantograph as a current collector has been described, but the present invention can also be applied to an electric vehicle drive device having a third rail current collector.

〔Effect of the invention〕

As is clear from the above explanation, if the present invention has J:
Is it possible to achieve high speed without reducing the protection performance against the protected R equipment? This has the effect of significantly reducing the number of times the IGI device is re-energized, and also significantly reducing the driver's stress.

[BRIEF DESCRIPTION OF THE DRAWINGS] Fig. 1 is a circuit diagram showing the configuration of an embodiment of the present invention with main parts shown in blocks; Fig. 2 is a time chart for explaining the operation of the embodiment; The figure is a schematic configuration diagram of the main circuit of a general electric vehicle drive device, and FIG. 4 is a schematic configuration diagram of a conventional protection device for an electric vehicle drive device. 1... Pantograph, 2... High speed breaker, 3...
・Filter reactor, 4...filter capacitor,
5... Thyristor, 7... Instrument transformer, 9...
Chopper, 10...Electric car drive type e machine, 218.2
4... Comparator, 22.25... Monostable multivibrator, 23... Gate amplifier circuit.

Claims (1)

[Claims] One end of a motor for driving an electric vehicle is connected to a current collector via a controller that controls the motor and a breaker that cuts off a power supply circuit, and a mutual junction point between the breaker and the controller is connected to the motor. In an electric vehicle drive device in which a filter capacitor is connected between the other end of the electric vehicle drive device, a switching element is connected in parallel to the filter capacitor via a resistance element, and a voltage detector detects a voltage across the filter capacitor. a first comparator that compares the output of the voltage detector with a reference value and generates a signal when the voltage across the filter capacitor reaches a first protection level; and a second comparator that generates a signal when the voltage across the filter capacitor reaches a second protection level higher than the first protection level; A protection device for an electric vehicle drive device, characterized in that the operation of the controller is stopped, the switching element is turned on and the breaker is turned off by a signal from the second comparator.