JPH0777857B2 - Regenerative power absorber protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention detects a failure of a device that absorbs excessive regenerative power generated when a DC electric vehicle is in regenerative operation, and quickly stops the device. The present invention relates to a protection device for a regenerative power absorption device.

[Conventional technology]

In recent years, DC electric vehicles often use a chopper to convert DC power taken from a power supply line to rotate a DC motor, or an inverter to convert AC power to a variable voltage and a variable frequency to rotate an AC motor. Therefore, when decelerating this DC electric vehicle or traveling downhill, it is easy to perform regenerative braking operation that converts the energy held by the DC electric vehicle into electric energy and returns it to the power supply side. Became.

FIG. 5 is an explanatory diagram showing a regenerative braking system of a DC electric vehicle. In FIG. 5, the substation 2 is composed of a transformer and a rectifier, and the DC power output from the substation 2 is supplied to the DC electric vehicles 5 and 6 through the power supply line 4. Therefore, these DC electric vehicles 5 and 6 take in this DC power from the pantographs 5P and 6P, rotate the DC motors 5M and 6M through the switches 5S and 6S, and then discharge the same to the ground via the wheels and rails. You are driving an electric car. However, illustration of a chopper or the like for controlling the DC motors 5M and 6M is omitted.

In FIG. 5, if one DC electric vehicle 5 is in the power running operation and the other DC electric vehicle 6 is in the regenerative operation, the electric vehicle 5 in the power running becomes I ₂ from the substation ₂ . Since the power running operation is performed by the sum of the electric current and the electric current I ₆ regenerated from the electric vehicle 6, the electric power output from the substation 2 may be a value obtained by subtracting the electric power regenerated from the electric vehicle 6. Therefore, energy saving can be achieved.

However, the electric vehicle 5 that is in the power running mode as described above
When the electric power required by the electric vehicle 6 decreases or the electric power regenerated from the electric vehicle 6 in the regenerative operation increases, the current I ₂ output from the substation 2 correspondingly decreases and finally becomes zero. Even if the output of the substation 2 becomes zero, if the electric vehicle 5 that is powering cannot completely consume the electric power regenerated from the electric vehicle 6, this surplus regenerated electric power raises the voltage of the power supply line 4 and the like. In order to prevent this, the regenerative power absorption device 3 is connected to the power supply line 4, and if the regenerated power has an excess, the regenerative power absorption device 3 absorbs it. That is, in FIG. 5, the output current from the substation 2
I ₂ is zero, the DC electric car 5 is power-driven by the current I ₆ regenerated from the DC electric car 6, and the surplus current I ₃ regenerated from the DC electric car 6 is supplied to the regenerative electric power absorber 3. By being absorbed, the illustrated regenerative braking system can continue to operate while being balanced.

FIG. 6 is a circuit diagram showing a conventional example of a regenerative power absorption device, in which an input capacitor 31 is connected between the feed line 4 and the ground, a load resistor 32 and a chopper 33 as a current continuation means. The regenerative power absorption device 3 is configured by connecting a series circuit of the above in parallel with the input capacitor 31.
The load resistor 32 and the chopper 33 are connected in series to the input capacitor 31 in order to increase the capacity of the regenerative power absorption device. In order to suppress the above, it is usual to employ a so-called polyphase operation method of operating these choppers with a phase difference, but in the present invention, in order to simplify the illustration, Series circuit is 1
They are in pairs.

When there is a surplus in the regenerative power, the regenerative current I ₃ flows from the power feeding line 4 into the regenerative power absorbing device 3 and raises the voltage Vc of the input capacitor 31. The deviation between the predetermined voltage Vs set by the voltage setter 36 and this capacitor voltage Vc is the voltage regulator.
The voltage adjuster 34 outputs the control signal V ₃₄ for reducing the input deviation to the phase shifter 35, and the phase shifter 35
Since the chopper 33 is controlled by the chopper 33, if the voltage Vc of the input capacitor 31 rises, the conduction ratio of the chopper 33 is adjusted to an appropriate value so as to make it the same value as the predetermined voltage Vs, and the intermittent flow that follows the Current will be dissipated in the load resistor 32.

The value of the predetermined voltage Vs set by the voltage setter 36 is set to be slightly higher than the voltage normally sent from the substation 2,
It is possible to prevent the regenerative electric power absorption device 3 from operating except when the electric vehicle is regeneratively operated to generate an excess of electric power, so that the electric power sent from the substation 2 is consumed by the regenerative electric power absorption device 3. It prevents waste of energy.

[Problems to be Solved by the Invention]

By the way, in the conventional circuit shown in FIG. 6, the voltage control system, mainly the voltage regulator 34 becomes abnormal, and the voltage Vc of the input capacitor 31 becomes lower than the predetermined voltage Vs determined by the voltage setting device 36. Nevertheless, the output V of the voltage regulator 34
_{When 34} is set to a value that operates the chopper 33,
Current always flows from the substation 2 to the regenerative power absorption device 3.

In the electric railway system, the regenerative operation pattern is usually intermittent, and the capacity of the load resistor 32 is designed according to this pattern, so that the voltage regulator 34 or the like is abnormal as described above. In addition to consuming unnecessary power in the regenerative power absorber 3, a continuous current flows through the load resistor 32, causing burnout, which may cause a serious accident such as a fire.

An object of the present invention is to provide a protection device for a regenerative power absorption device that can prevent burnout of a load resistance by detecting an abnormality in a voltage adjusting unit that controls the regenerative power absorption device and quickly stopping the operation of the device. To do.

[Means for Solving the Problems]

In order to achieve the above object, in the present invention, a capacitor connected between a power supply line for supplying DC power to an electric vehicle and the ground, and a required set of current interrupting means connected in parallel to the capacitor. Based on the series circuit with the resistor, the comparator that detects that the voltage value across the capacitor has exceeded the first set value, and the voltage deviation output of this comparator,
A voltage adjusting means for outputting a control signal for matching the voltage value across the capacitor with the first set value, and a current interrupting control signal for adjusting the flow rate of the current interrupting means based on the control signal output by the voltage adjusting means. A phase shifter for outputting to the means, and a regenerative power absorption device protection device that absorbs surplus power when the electric vehicle is in regenerative operation to the resistor. A low voltage detector that detects that the voltage is below a second set value that is lower, an operation detector that monitors the level of a control signal output by the voltage adjusting means to detect the operation of the voltage adjusting means, and a low voltage A logical product circuit for calculating a logical product of the output of the detector and the output of the operation detector, and a timer for detecting that the arithmetic output of the logical product circuit continues for a predetermined allowable time or longer and judging that the voltage adjusting means has failed. Circuit and this Holding the determination output of the timer circuit, including a holding circuit for outputting a signal for stopping the operation of the current interrupting means.

[Work]

With the above configuration, the input voltage to the regenerative power absorber, and the output level of the voltage adjusting means for outputting a control signal to control the current interrupting means constituting the regenerative power absorber,
Is constantly monitored and the input voltage is a value less than the second set value (low voltage set value) below the first set value set as a reference for operating the voltage adjusting means,
If the voltage adjusting means detects the state of outputting the control signal, it is judged that the voltage adjusting means is out of order, and immediately instructs the DC disconnecting means to stop the operation.

〔Example〕

FIG. 1 is a circuit diagram showing an embodiment of the present invention.
The details of the invention are described below by means of the figures.

In FIG. 1, an input capacitor 31 is connected between the feed line 4 and the ground, and by connecting in parallel to the input capacitor 31 in a series circuit of a load resistor 32 and a chopper 33 as a current interrupting means, The main circuit of the regenerative power absorber is formed. In order to increase the capacity of this regenerative power absorber, it is normal to connect a required number of series circuits of a load resistor and a chopper in parallel to the input capacitor 31. In order to suppress the harmonic current, a plurality of choppers are operated with a phase difference, so-called polyphase operation method is adopted, but in the present invention, in order to simplify the illustration,
The above-mentioned series circuit is one set.

If the regenerative operation of an electric car causes an excess in regenerative power,
Input capacitor due to regenerative current flowing from power supply line 4
The voltage Vc of 31 rises. A predetermined voltage Vs has been set in advance by the voltage setting device 36, and when the input capacitor voltage Vc exceeds this predetermined voltage Vs, the deviation between these two voltages causes a voltage regulator.
The voltage adjuster 34 inputs a control signal for making the input deviation zero to the phase shifter 35, and the phase shifter 35 controls the chopper 33 in response to the control signal. If the voltage Vc of the input capacitor 31 rises, this is set to the predetermined voltage Vs.
As in the case of the conventional circuit described above in FIG. 6, the duty factor of the chopper 33 is adjusted to an appropriate value and the intermittent current flowing accordingly is consumed by the load resistor 32 in order to obtain the same value as Is.

In the present invention, the abnormality detection circuit 40 and the low voltage setting device 50 are provided so as to detect the abnormality of the voltage regulator 34. That is, the predetermined voltage set by the voltage setter 36
The low voltage setting value V _B from the low voltage setting device 50 set to a value lower than Vs, the voltage Vc of the input capacitor 31 and the output C of the voltage controller 34 are input to the abnormality detection circuit 40, and The voltage V _B and the voltage V c are constantly compared. Despite if the input capacitor voltage Vc becomes lower than the low voltage setting value V _B, the outputs of the control signal C voltage regulator 34 is not zero, the abnormality detection circuit 40 is the voltage Controller 34
Is determined to be abnormal, a signal D is output to the phase shifter 35, the operation of the chopper 33 is stopped via the phase shifter 35, and the load resistor 32 is prevented from burning.

FIG. 2 is a block diagram showing the inside of the abnormality detection circuit in the embodiment circuit shown in FIG. 1. This abnormality detection circuit 40 includes an AVR operation detector 41, a low voltage detector 42, and a logical product element 43. , A timer 44 and a flip-flop 45.

In FIG. 2, the AVR motion detector 41 is a voltage regulator 34.
Of the input signal C and outputs a logical zero signal when the value of the input signal C is zero, and outputs a logical one signal when the value of the input signal C is a value other than zero. On the other hand, the low voltage detector 42
, And the low voltage set value V _B are input to constantly compare the magnitude of both inputs. When V _C > V _B , the low voltage detector 42 outputs a logic zero signal. , When the magnitude relationship between both inputs is reversed and V _C <V _B , the output changes to a logic 1 signal.

The logic signals output from the AVR operation detector 41 and the low voltage detector 42 are supplied to the phase shifter 35 via the AND element 43, the timer 44 and the flip-flop 45. Here, the timer 44 is for delaying the output of the logical product element 43 for a certain period of time, and this is provided in order to prevent malfunction due to the time delay element in the voltage regulator 34. Further, the flip-flop 45 is for storing an abnormal state, and after the abnormal signal is received from the timer 44, even if the output from the timer 44 changes, the flip-flop 45 of the phase shifter 35 This is for preventing the output signal from changing, and the output of the phase shifter 35 is locked by the signal output from the flip-flop 45 indicating the abnormality, and the chopper 33 is stopped.

FIG. 3 is an operation waveform diagram showing the operation of each part of the embodiment circuit shown in FIG. 1 when the voltage regulator is normal.
The figure is an operation waveform diagram showing the operation of each part of the embodiment circuit shown in FIG. 1 when the voltage regulator is abnormal. In both FIGS. 3 and 4, (a) is the input voltage, that is, the input voltage. The change in the voltage Vc of the capacitor 31 is shown in (b) as the low voltage detector 42.
Changes the output of the logic signal F, (c) changes the output signal C of the voltage regulator 34, and (d) changes the AVR motion detector 41.
(E) shows the change of the logic signal G which the AND element 43 outputs, (f) shows the change of the logic signal H which the timer 44 outputs, (g) Represents changes in the logic signal D output from the flip-flop 45, that is, the abnormality detection circuit 40.

As is apparent from FIGS. 3 and 4, when the voltage regulator 34 is normal, if the electric vehicle is in regenerative operation and there is an excess in regenerative power, the regenerative power absorption device operates. As a result, the surplus power is absorbed while maintaining the input voltage Vc at a predetermined value Vs. When the regenerative operation ends here, the regenerative current becomes zero and the input capacitor voltage Vc begins to drop.
The output C of the voltage regulator 34 does not immediately become zero, but gradually decreases with a certain delay (see FIG. 3C). Since the chopper 33 is operating during this period, when the input capacitor voltage Vc continues to drop and reaches the low voltage set value V _B , the low voltage detector 42 operates and its output F becomes a logic 1 signal, and therefore The output G of the logical product element 43 outputs a logical 1 signal from this time until the output C of the voltage regulator 34 becomes zero (see FIG. 3 (e)). Is blocked by the timer 44 and no abnormal signal is output from the flip-flop 45. Of course, the chopper 33 automatically stops its operation when the output C of the voltage regulator 34 becomes zero.

However, when there is an abnormality in the voltage regulator 34, even if the value of the input voltage Vc is reduced to the low voltage set value V _B or less by stopping the regenerative operation of the electric vehicle, the voltage regulator 34 The output C does not decrease, so the output E of the AVR motion detector 41 will continue to output a logic 1 signal. Therefore, when the low voltage detector 42 detects a decrease in the input voltage Vc, the output G of the AND element 43 changes to a logic 1 signal.
As long as 34 is abnormal, this logic 1 signal continues, and therefore, when the time limit T by the timer 44 elapses, the output H of the timer 44 and the output D of the flip-flop 45 both become a logic 1 signal and the phase shifter 35 Will be given to the chopper 33.

〔The invention's effect〕

According to the present invention, it is detected that the power supply line voltage rises due to the surplus regenerative electric power generated by the regenerative operation of the electric vehicle, and the voltage adjusting means outputs the control signal for matching the power supply line voltage with the predetermined value. In the regenerative power absorption device configured to absorb the surplus regenerative power by operating the current interrupting means, the input voltage of the regenerative power absorption device is set below the predetermined value. When the voltage adjusting means is outputting the control signal despite the voltage being lower than the low voltage setting value, it is determined that the voltage adjusting means has a failure and the operation of the current interrupting means is stopped. Therefore, it is possible to avoid the risk of overheating and burnout of the resistor, which is caused by continuous use of the resistor for power absorption designed for intermittent use, and the risk of fire. Further, even though there is no surplus in the regenerated electric power, it is possible to eliminate the possibility that the regenerative electric power absorber operates unnecessarily and consumes the electric power.

[Brief description of drawings]

1 is a circuit diagram showing an embodiment of the present invention, FIG. 2 is a block diagram showing the inside of an abnormality detecting circuit in the embodiment circuit shown in FIG. 1, and FIG. 3 is a diagram showing a normal voltage regulator. FIG. 4 is an operation waveform diagram showing the operation of each part of the embodiment circuit shown in FIG. 1, and FIG. 4 shows the operation of each part of the embodiment circuit shown in FIG. 1 when the voltage regulator is abnormal. It is an operation waveform diagram. FIG. 5 is an explanatory diagram showing a regenerative braking system of a DC electric vehicle, and FIG. 6 is a circuit diagram showing a conventional example of a regenerative power absorbing device. 2 ... Substation, 3 ... Regenerative power absorber, 4 ... Feed line, 5,6 ... DC electric car, 5M, 6M ... DC motor, 5P, 6P
...... Pantograph, 5S, 6S ...... Switch, 31 ...... Input capacitor, 32 ...... Load resistance, 33 ...... Chopper as current interruption means, 34 ...... Voltage regulator, 35 ...... Phase shifter, 36 ......
Voltage setting device, 40 ... Abnormality detection circuit, 41 ... AVR operation detector, 42 ... Low voltage detector, 43 ... AND element, 44 ... Timer, 45 ... Flip-flop, 50 ... Low voltage Setting device.

Claims (1)

[Claims] 1. A capacitor connected between a power supply line for supplying DC power to an electric vehicle and the ground, and a series circuit of a required set of current interrupting means and a resistor connected in parallel to the capacitor, A comparator that detects that the voltage value across the capacitor is equal to or greater than a first set value, and the voltage value across the capacitor matches the first set value based on the voltage deviation output of the comparator. And a phase shifter that outputs a control signal to the current interrupting means for adjusting the flow rate of the current interrupting means based on the control signal. A protection device for a regenerative power absorption device that absorbs surplus power during operation to the resistor, wherein the voltage value across the capacitor is equal to or less than a second set value that is less than the first set value. Detect A low voltage detector, an operation detector that monitors the level of the control signal to detect the operation of the voltage adjusting means, and a logic that calculates the logical product of the output of the low voltage detector and the output of the operation detector A product circuit, a timer circuit that detects that the operation output of the AND circuit continues for a predetermined allowable time or longer and determines that the voltage adjusting means has failed, and a determination output of the timer circuit that holds the current interruption. A holding device for outputting a signal for stopping the operation of the means, and a protection device for the regenerative power absorption device, comprising: