JPH0526708B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a fail-safe phase detection device for train detection equipped with a phase shift regulator.

<Prior art> For example, in a track circuit for railway signals, one of the train detection methods is to detect the presence or absence of a train by detecting the phase between a local signal as a reference signal and a track signal of the train running track. The system is known.

FIG. 3 shows a conventional phase detection device applied to such a train detection system.

In the figure, for example, the reference signal is passed through a phase shift adjuster 1 to a clamp circuit consisting of a capacitor C ₁ and a diode D ₁ to the power supply voltage of an operational oscillator 2, which will be described later.
After being clamped to Vs, it is input to one input terminal of an operational oscillator 2 that constitutes a fail-safe two-input AND gate circuit. Further, the control signal is differentiated by a differentiating circuit 3 consisting of a capacitor C ₂ and a resistor R ₁ and inputted to the other input terminal of the arithmetic oscillator 2.

The operation of such a phase detection device will be explained with reference to FIG. 4. A reference signal is phase-adjusted by a phase shift adjuster 1 so as to have a prescribed phase relationship with a control signal, and is input to an operational oscillator 2. . Further, the control signal is differentiated by a differentiating circuit 3, and is inputted to the arithmetic oscillator 2 as a differentiated pulse signal. For example, when applied to a train detection system, etc., if there is no train in the track circuit, the reference signal and the control signal are in phase, and the arithmetic oscillator 2
It oscillates as shown in the figure, and the oscillation output excites the track relay to output a train absence signal.

On the other hand, when a train enters the track circuit,
For example, by advancing the phase of the control signal and providing a phase signal at the position of the broken line in FIG.
output is stopped, the track relay is de-energized, and a train detection signal is output. Note that when applied to such a train detection system, a self-holding circuit and a rectification circuit for the operational oscillator 2 are required.

<Problems to be Solved by the Invention> Incidentally, such a phase detection device is provided with a phase shift adjuster to bring the reference signal and the control signal into a prescribed phase relationship. An example of this phase shift regulator is shown in FIG. That is, a series circuit of a capacitor C and a resistor R is connected to the secondary side of the transformer T, and the output is output from the midpoint between the capacitor C and the resistor R, with the midpoint of the transformer T being grounded, for example.

In such a phase shift regulator, the output V is given by V=r/r-jX _C E-E/2 (1). However, E is the secondary voltage of the transformer T, r is the resistance value of the resistor R, and Xc is the capacitance reactance of the capacitor C.

When formula (1) is transformed, V=1/1-jX _C /rE-E/2 (2), and the phase of this phase shift adjuster changes depending on X _C /r.

Here, most of the failure modes of the phase shift regulator are disconnection of the winding of the transformer T, resistor R, and capacitor C, and short circuit of the capacitor C.

In the case of a short-circuit failure of the capacitor C or an open-circuit failure of the resistor R, the phase of the output _V is
The phase shifts to the side that lags behind the phase set by r, but if the capacitor C is disconnected, the phase shifts to the opposite side.

Therefore, for example, if a differential phase signal is given by advancing the phase of the control signal as shown by the broken line in FIG. 6, and a phase shift adjuster is inserted on the reference signal side, the phase shift adjuster If the failure mode is on the phase lag side (as shown by the broken line in Figure 6), the detection output is likely to disappear, so it is a fail-safe, but if it is on the phase lead side, as shown in Figure 7, it is difficult to disappear, leading to malfunction. It is not fail-safe (it is conceivable that even when a phase signal based on a control signal is received as shown by the dotted line, it cannot be detected).

For this reason, the direction of the phase shift can be determined in the case of a break in the resistor R because the direction of the phase shift can be limited, but the direction of the phase shift cannot be determined in the case of a break or short circuit in the capacitor C, so the fail-safe side can be determined. Therefore, it was not possible to ensure fail-safety of a phase detection device using such a phase shift adjuster.

In addition, when the positional relationship of the capacitor C and the resistor R is reversed in the phase shift adjuster as shown in FIG. You can't choose sides.

Therefore, the present invention has been made in view of the above-mentioned circumstances, and is a phase detection device using a bridge type phase shift regulator in which a series circuit of a capacitor and a resistor is connected to the secondary side of a transformer. The purpose of this invention is to ensure fail-safe performance even in the event of disconnection or short-circuiting of the capacitor.

<Means for solving the problem> For this reason, the phase detection device for train detection of the present invention has the following features:
The phase adjuster 11 includes a phase adjuster 11, a differentiation circuit 3, a fail-safe AND gate circuit 12, and a current sensor 13. a transformer T, one of which is input to the primary winding side and a control signal for providing a phase signal whose phase is shifted;
It is equipped with a series circuit of a capacitor C and a resistor R connected to the secondary winding of the transformer T, and has a configuration in which the voltage between the midpoint of the secondary winding and the connection point of the capacitor C and the resistor R is output. The phase of the input signal of the transformer T is adjusted by the capacitance reactance of the capacitor C and the resistance value of the resistor R so as to have a predetermined phase relationship with respect to the other signal that is not input, and is output. The differentiating circuit 3
is provided in either the reference signal system or the control signal system, and is configured to convert an input signal into a differential pulse and output it to the AND gate circuit 12, and the AND gate circuit 12 is configured to: The configuration is such that at least the differentiated pulse signal from the differentiating circuit 3 and the signal from the system side where the differentiating circuit 3 is not provided are input, and when both input signals are at a level higher than the power supply voltage, an output is generated and a train is detected. The current sensor 13 is configured to detect the presence or absence of a current flowing through a series circuit of a capacitor C and a resistor R of the phase adjuster 11. The phase shift regulator 11 is configured such that an output is generated when the capacitor C is not in use.
When the reference signal side is inserted, the output phase is shifted in the opposite direction to the generated phase signal, and when the control signal side is inserted, the output phase is shifted in the same direction as the phase signal, and a short circuit failure occurred in capacitor C. When the phase difference between the reference signal and the phase signal increases, and when at least one of the capacitor C and the resistor R is disconnected,
3 is stopped, and the train detection output based on the output of the AND gate circuit 12 is forcibly stopped.

<Operation> As a result, the phase shift between the reference signal and the phase signal is magnified in the case of a capacitor short-circuit failure of the phase adjuster, thereby increasing the detection sensitivity and providing safe operation. Furthermore, in the case of a disconnection failure in a capacitor or resistor, no current flows and this is detected by a current sensor and the phase detection output is forcibly stopped. Therefore, fail-safe can be ensured against a failure of the phase adjuster.

<Example> An embodiment of the present invention will be described below.

FIG. 1 shows a circuit diagram of this embodiment.

In the figure, reference numeral 11 denotes a phase shift adjuster applied to this embodiment. For example, a series circuit of a capacitor C and a resistor R is connected to the secondary side of a transformer T to which a reference signal is input, and the middle point of the transformer T is grounded. connect to
The output terminal is the midpoint between the capacitor C and the resistor R.

The output terminal of the phase shift adjuster 11 is input to an operational oscillator 12 that constitutes a fail-safe three-input AND gate circuit via a capacitor C _P and a variable resistor R _P. Note that a fixed phase shift regulator is configured by the capacitor C _P and the resistor R _P. diode
D ₂ is for clamping the output of the phase shift adjuster 11 to the power supply voltage V _S of the arithmetic oscillator 12.

Further, a current sensor 13 such as a current transformer is inserted between the secondary side of the transformer T and the capacitor C, and its output is rectified by a rectifier circuit 14 and input to the arithmetic oscillator 12.

A control signal is input to the arithmetic oscillator 12 via a differentiating circuit 3 similar to the conventional one. In this embodiment, the phase signal is given by advancing the control signal, and the input impedance on the operational oscillator 12 side as seen from the midpoint between the resistor R and the capacitor C is assumed to be sufficiently high.

The arithmetic oscillator 12 is conventionally known and has a fail-safe configuration in which it emits an oscillation output when all inputs are equal to or higher than a certain threshold value Vth higher than the power supply voltage V _S , and does not output in the event of a failure.

A concrete example of this arithmetic oscillator 12 is shown in FIG.

It consists of three NPN transistors T ₁ to _{T 3} and four resistors R ₂ to R ₅ and two Zener diodes.
It consists of ZD ₁ and ZD ₂ .

Its operation is such that, for example, when each input a to c becomes higher than the power supply voltage V _S when the transistor T ₁ is in the OFF state, the transistor T ₂ is turned on → the transistor
T ₃ OFF → Transistor T ₁ ON → Transistor
T ₂ OFF → Transistor T ₃ ON → Transistor
Transistors T ₁ to _{T 3} are ON- as in T ₁ OFF...
Repeats OFF and generates oscillation output V ₀ .

On the other hand, if any of the input levels becomes lower than the power supply voltage, the operations of the transistors T ₁ to _{T 3} are not reversed and oscillation is stopped.

The selection conditions for the Zener voltages VZD ₁ and VZD ₂ of the Zener diodes ZD ₁ and ZD ₂ are VZD ₂ < V _S < VZD ₁
It is better to

Next, the operation will be explained.

During normal operation, the differential signal based on the control signal is shown by a solid line with respect to the reference signal input to the arithmetic oscillator 12 after phase adjustment by the phase shift adjuster 11 as shown in FIG. If the control signal is input at the position, the arithmetic oscillator 12 oscillates, and if the control signal advances in phase as shown by the broken line, the oscillation output stops. Therefore, phase detection is performed depending on the presence or absence of the output of the arithmetic oscillator 12.

Next, a description will be given of what happens when the phase shift regulator 11 fails.

When the capacitor C is short-circuited, in this embodiment, the phase of the reference signal shifts to the delayed side as shown in FIG. In this case, as shown in the figure, since the phase signal is on the leading side, there is no output from the calculation oscillator 12, resulting in a fail-safe situation.

Furthermore, if either the capacitor C or the resistor R is disconnected, no current will flow through the series circuit of the capacitor C and the resistor R no matter which one is disconnected. Therefore, since the output of the current sensor 13 disappears, one input of the arithmetic oscillator 12 becomes lower than the threshold value Vth, and the arithmetic oscillator 12 does not output, resulting in a fail-safe situation.

As described above, according to the configuration of this embodiment, there is no output from the arithmetic oscillator 12 even if the phase shift regulator 11 is disconnected or short-circuited, making the phase detection device fail-safe.

In addition, in the case of a configuration in which a phase signal is given by delaying the phase of the control signal, contrary to this embodiment,
If the position of the capacitor C and the resistor R of the phase adjuster 11 is replaced with that shown in FIG. 8, the phase will shift to the leading side in the event of a short-circuit failure of the capacitor C, and fail-safe performance in this case can be ensured.

By the way, when the phase shift adjuster 11 is inserted into the control signal system, contrary to the present embodiment, when giving a phase signal by advancing the phase of the control signal, conversely to the above embodiment, capacitor C failure occurs. It is assumed that the position of the capacitor C and the resistor R is opposite to that of FIG. 1, that is, the phase shift adjuster shown in FIG. 8, so that the phase shifts in the direction of further advancement. Further, when providing a phase signal by delaying the phase of the control signal, a phase shift adjuster shown in FIG. 1 is used.

In other words, when a phase shift adjuster is inserted into the reference signal system, the phase is shifted in the opposite direction to the phase signal when capacitor C is short-circuited, and when inserted into the control signal system, the phase is shifted in the same direction as the phase signal. It is necessary to have a configuration that shifts.

In this embodiment, the output of the current sensor 13 is input to the calculation oscillator 12, but the output of the current sensor 13 drives a relay, and this relay turns the output from the calculation oscillator 12 on and off. You can also use it as

<Effects of the Invention> As described above, according to the present invention, in a phase detection device using a bridge-type phase shift regulator in which a series circuit of a secondary side capacitor of a transformer and a resistor is connected, The output of the phase detection device can be set to zero not only when the capacitor is short-circuited, but also when the capacitor or resistor is disconnected. Therefore, the phase detection device can be constructed in a fail-safe manner, and the safety of the train detection system can be improved.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram of an embodiment of the present invention, Fig. 2 is a circuit diagram showing a specific example of an operational oscillator, Fig. 3 is a circuit diagram showing a conventional example, and Fig. 4 explains the operation of the same conventional example. Figure 5 is a diagram of the phase shift regulator, Figures 6 and 7 are diagrams explaining the fail-safe of the phase shift regulator, and Figure 8 is a diagram showing another example of the phase shift regulator. It is. 3... Differential circuit, 11... Phase shift adjuster, 12...
... Arithmetic oscillator (AND gate circuit), 13 ... Current sensor, 14 ... Rectifier circuit, C ... Capacitor,
R...Resistance.

Claims (1)

[Claims] 1. Phase adjuster 11, differentiation circuit 3, fail-safe AND gate circuit 12, and current sensor 1
3, and the phase adjuster 11 includes a reference signal and a control signal for providing a phase signal whose phase is shifted from the reference signal depending on the presence or absence of a train. A series circuit of a capacitor (C) and a resistor (R) is connected to the secondary winding of the transformer T. ), and the phase of the input signal of the transformer T is determined by the capacitive reactance of the capacitor C and the resistance value of the resistor R relative to the other signal that is not input. The differential circuit 3 is provided in either the reference signal system or the control signal system, and converts the input signal into a differentiated pulse. It is configured to output to the AND gate circuit 12, and the AND gate circuit 12 is configured to receive at least the differentiated pulse signal from the differentiating circuit 3 and the signal on the system side where the differentiating circuit 3 is not provided. The current sensor 13 is configured to generate an output and generate a train detection output when both input signals are at a higher level than the power supply voltage. It is configured to detect the presence or absence of current flowing in the series circuit, and is configured so that no output is generated when no current flows in the series circuit, and in the event of a short-circuit failure of the capacitor C, the phase shift regulator 11 is When a reference signal side is inserted, the output phase is shifted in the opposite direction to the generated phase signal, and when a control signal side is inserted, the output phase is shifted in the same direction as the phase signal, so that when a short circuit failure occurs in capacitor C,
The phase difference between the reference signal and the phase signal is expanded, and when at least one of the capacitor C and the resistor R is disconnected, the output of the current sensor 13 is stopped and the AND gate circuit 1
1. A phase detection device for train detection, characterized in that the train detection output based on the output of No. 2 is forcibly stopped.