JP2020194232A - Redundant constant current source and sensor system - Google Patents

Abstract

To provide a constant current source with a low failure rate by realizing with less redundancy a control device that has operation continuity in an event of a failure.SOLUTION: A constant current source includes: a plurality of current control sources 10-1 to 10-n that can control current outputs; current combining means 20 that combines the current outputs of the plurality of current control sources 10-1 to 10-n; and current detection means 30-1 to 30-n provided for each of current control sources 10-1 to 10-n that detects the output current in the subsequent stage of the current combining means 20. The plurality of current control sources 10-1 to 10-n performs feedback-control so that output currents I1 to In of the plurality of current control sources 10-1 to 10-n that are detected by the current detection means 30-1 to 30-n make a target value of a total current.SELECTED DRAWING: Figure 1

Description

The present invention relates to a redundant constant current power supply and a sensor system.

When the control target is located far away from the control device, the sensor is installed near the control target, so that the sensor is installed far away from the control device as well as the control target. In this way, the exchange of power supply and measurement information between the control device and the sensor far away is often not by voltage but by current loop.

When the control device and the sensor are used in a critical application, the reliability and safety of the control device and the sensor are required. In order to improve reliability and safety, a method of making system components redundant is widely used.
For example, in Japanese Patent Application Laid-Open No. 8-95650 shown in Patent Document 1, as a method of making a constant current power supply redundant, a current detection signal of a shunt resistor is added by an adder circuit, and a variable command common to each voltage variable terminal TRM is added. A method of supplying as a voltage and keeping the output current of each power supply main body constant by this variable command voltage is disclosed.

Japanese Unexamined Patent Publication No. 8-95650

Patent Document 1 discloses that it is possible to continue power supply by redundancy even when a failure occurs in a constant current power supply. However, the variable command voltage output circuit for controlling the redundant constant current power supply and its peripheral circuits have a single point of failure, and it is desirable to consider further reduction of the failure rate of the single point of failure. Is done.

Specifically, in FIG. 1 of Patent Document 1, the operational amplifiers 22 to the variable command voltage output circuit have a single point of failure, and the shunt resistors I1-3 to the operational amplifiers 24 and 24AB also have a single point of failure depending on the failure mode. It becomes a point. In FIG. 2 of Patent Document 1, the shunt resistor 5, the reference power supply 8, and the error amplifier 7 are single points of failure. In FIG. 3 of Patent Document 1, the shunt resistor I to the operational amplifier 17 to the variable command voltage output circuit 19 are single points of failure. The failure rate of these single points of failure is estimated to be about several hundreds to several thousand FITs, and further consideration is required for use in a system requiring a failure rate lower than this.
Therefore, an object of the present invention is to provide a constant current power source having a lower failure rate.

In order to solve the above problems, a typical redundant constant current power supply and sensor system of the present invention can be used.
With multiple current control power supplies that can control the output current,
A current synthesizing means for synthesizing the current outputs of the plurality of current control power supplies,
Each current control power supply has a current detecting means for detecting the output current in the subsequent stage of the current combining means.
The output current detected by the current detecting means is controlled to be the total current target value.

As described above, according to the present invention, it is possible to provide a constant current power source having a lower failure rate.
Issues, configurations and effects other than those described above will be clarified by the description of the following embodiments.

It is an example of the circuit diagram of Example 1 of this invention. This is an example of a circuit diagram showing a configuration example of the current synthesizing means 20 and the current detecting means 30-1 to 30-n in the first embodiment. This is an example of a circuit diagram showing a configuration example of the current detecting means 30-1 to 30-n. This is an example of a circuit diagram showing a configuration example of the current detecting means 30-1 to 30-n. It is a figure which shows the operation example of Example 1. FIG. This is an example of a circuit diagram when a ballast resistor Rb is inserted in series with the output. In the second embodiment, it is an example of the circuit diagram in the case where the output current is detected for each current control power supply 10-1 to 10-n. It is a figure which shows the operation example of Example 2. FIG. This is an example of a circuit diagram in the case where the individual current detecting means 40-1 to 40-n are used as shunt resistors and the operation switching means is used as the minimum value circuit. It is an example of the circuit diagram of the minimum value circuit (MIN). It is a figure which shows the operation example in the case of the circuit diagram of FIG. This is an example of the circuit diagram of the third embodiment in which countermeasures against short-circuit failures of the diodes D1 and Dn are taken. In the fourth embodiment, it is an example of a circuit diagram in which the outputs of the individual current detecting means 40-1 to 40-n are added to obtain the current detecting means 30-1 to 30-n. In the fourth embodiment, it is an example of a circuit diagram for adding the outputs of the individual current detecting means 40-1 to 40-n. In the fifth embodiment, it is an example of a circuit diagram for switching the gain of the individual current detecting means 40-1 to 40-n at the time of failure. In the sixth embodiment, it is an example of a circuit diagram when a current control power supply is connected in series. In the sixth embodiment, it is an example of the circuit diagram when the ballast resistor is provided in parallel with the current control power supply. In the seventh embodiment, it is an example of a circuit diagram when a pseudo load for inspection 60-n is provided in order to configure standby redundancy. In Example 7, it is an example of the circuit diagram which shows the structural example of the artificial load 60-n for inspection. This is an example of a system configuration diagram of a sensor system using the redundant constant current power supply of the eighth embodiment. In the eighth embodiment, it is an example of the system configuration diagram of the sensor system when the current synthesis means is provided near the sensor 200.

Hereinafter, examples of the present invention will be described with reference to the drawings.
Generally, a power supply that controls the output current to a constant value is called a "constant current power supply" or a "current source", but in the present specification, the output current is variable depending on the gain of the fed-back current value. A power source is called a "current control power source".
Further, in the present specification, n means the number of constant current power supplies used for the current control power supply.

FIG. 1 is a circuit diagram of the first embodiment. The current control power supplies 10-1 to 10-n each output currents I1 to In, and the current synthesis means 20 synthesizes the currents I1 to In and outputs a current of Io = (I1 + ... + In) to supply the load RL. To do. The output current Io of the current combining means 20 is detected by the current detecting means 30-1 to 30-n and fed back to the current control power supplies 10-1 to 10-n, respectively. In the current control power supply 10-1 to 10-n, the output currents I1 to In are feedback-controlled so that the difference between the fed-back current value and the target value becomes zero.

According to this embodiment, even if any of the current control power supplies 10-1 to 10-n fails and the current cannot be output, the other normal current control power supply can be used as the current detection means 30-1 to 30-. By feedback-controlling the output currents I1 to In so that the difference between the current value fed back from n and the target value becomes zero, the difference between Io and the target value is zero for the entire system, that is, Io is the target value. It works so that
It is desirable that the current control power supply 10-1 to 10-n be realized by a switching regulator rather than a linear regulator from the viewpoint of improving efficiency and reducing heat generation.

In this embodiment, a failure mode in which the output current decreases is assumed, but in the failure mode in which the output current increases, it is conceivable to attach an overcurrent protection circuit to limit the current. For example, if a fuse, a PTC (positive temperature coefficient) thermistor, or the like is inserted in series with the current output, the problem caused by the failure of the overcurrent protection circuit itself can be solved.
Further, it is desirable that the power source for supplying power to the current control power supply 10-1 to 10-n also has a separate power grid as shown in FIG. 1 or an uninterruptible power supply in preparation for a power failure or the like.

FIG. 2 is a circuit diagram showing a configuration example of the current combining means 20 and the current detecting means 30-1 to 30-n in the first embodiment.
The current synthesizing means 20 may simply connect the outputs of the current control power supplies 10-1 to 10-n in parallel at one point in the output terminals of the current control power supplies 10-1 to 10-n. However, in order to deal with a ground fault in the output terminals of the current control power supply 10-1 to 10-n, it is desirable that the current synthesis means 20 is composed of directional elements that allow current to flow in only one direction. The unidirectional element is preferably composed of diodes D1 to Dn as shown in FIG.

The current detecting means 30-1 to 30-n can be composed of shunt resistors Rs as shown in FIG. The current detecting means can be configured by a current transformer, a magnetic sensor, or the like, but the shunt resistor Rs is desirable from the viewpoint of cost and reliability.

3 and 4 are circuit diagrams showing other configuration examples of the current detecting means 30-1 to 30-n.
FIG. 3 is a circuit in which the voltage across the common shunt resistor Rs is input to the operational amplifiers Q1 to Qn via the resistor Ri. By providing an independent current detecting means for each current control power supply in which the resistor Ri is connected in series to the input terminal of each operational amplifier, the influence of any failure of the current detecting means 30-1 to 30-n can be further affected. It does not affect and the current detecting means does not become a single point of failure. Further, in preparation for a short-circuit failure of the resistor Ri, it is possible to realize it with a plurality of resistors in which a plurality of resistors Ri are connected in series.

FIG. 4 is a circuit diagram in the case where the shunt resistors Rs1 to Rsn are individually provided for each of the current detecting means 30-1 to 30-n. In this way, by individually providing the shunt resistors Rs1 to Rsn for each of the current detecting means 30-1 to 30-n, one of the shunt resistors Rs1 to Rsn is short-circuited or the resistance value is slightly changed. When the above occurs, the influence can be limited to the current detecting means 30-1 to 30-n. However, if any of the shunt resistors Rs1 to Rsn is disconnected, the output current Io cannot flow. In order to avoid the influence of such a failure, the shunt resistors Rs1 to Rsn may be realized by a plurality of resistors connected in parallel as shown in FIG.

FIG. 5 shows an operation example of the redundant constant current power supply of the first embodiment. For the sake of simplicity, FIG. 5 shows an operation example of only two current control power supplies 10-1 to 10-2. FIG. 5 shows an operation when a failure occurs in the current control power supply 10-1 among the current control power supplies 10-1 to 10-2 at time Tf. Before the time Tf, the current control power supplies 10-1 to 10-2 output the current Io as a whole while sharing the output currents I1 and I2, respectively. After the time Tf, the output current I1 of the current control power supply 10-1 becomes zero, and the current Io is covered only by the output current I2 of the current control power supply 10-2 to continue the operation as a constant current power supply.

The reason why I1 and I2 are not equal as shown in the solid line A before the time Tf is that, for example, the current control power supplies 10-1 to 10-n in FIG. 1 do not operate to keep the individual output currents I1 to In constant. This is because it is affected by the variation of the parts of the current control power supplies 10-1 to 10-2.
Further, the reason why I1 and I2 fluctuate with time as shown by the broken line B is that the current control power supplies 10-1 to 10-n do not operate to keep the individual output currents I1 to In constant, so that the current control is performed. This is because the signal transmission loop until feedback is applied becomes long even when there are two power supplies. Specifically, a control loop having twice the normal length of the current control power supply 10-1 → current detection means 30-2 → current control power supply 10-2 → current detection means 30-1 → current control power supply 10-1. Will increase the feedback delay time and make the system unstable.

In order to alleviate the instability as described above, it is also possible to insert a ballast resistor Rb in series with the output of the current control power supply 10-1 to 10-n as shown in FIG. Considering the balance with the loss, the value of the ballast resistance Rb is about 5-10% of the load resistance RL.

FIG. 7 shows an example in which individual current detecting means 40-1 to 40-n for detecting the output current and operation switching means 50-1 to 50-n are provided for each current control power supply 10-1 to 10-n. The operation switching means 50-1 to 50-n selects the output of the individual current detecting means 40-1 to 40-n input to the terminal N when all the current control power supplies 10-1 to 10-n are normal. It feeds back to the current control power supply 10-1 to 10-n.
If any of the current control power supplies 10-1 to 10-n is abnormal, the output of the current detection means 30-1 to 30-n input to the terminal F is selected to select the current control power supply 10-1. Feedback is given to 10-n. In the current control power supply 10-1 to 10-n, the output currents I1 to In are feedback-controlled so that the difference between the fed-back current value and the target value becomes a cello. That is, the output current of each current control power supply is controlled so that the total output of the individual current detection means becomes the total current target value.

According to this embodiment, when all the current control power supplies 10-1 to 10-n are normal, the current control power supply 10-1 is controlled by the current detection value by the individual current detection means 40-1 to 40-n. The operation can be stabilized by performing an operation of keeping the individual output currents I1 to 10 of 10 to n constant.

Here, since there is a relationship of Io = (I1 + ... + In), considering the balance of the load of the current control power supply 10-1 to 10-n in the normal state, I1 = I2 = ... = In. desirable. Then, at this time, the relationship I1 = I2 = ... = In = Io / n is established. That is, the output value of the current detecting means 30-1 to 30-n in the normal state is n times the output value of the individual current detecting means 40-1 to 40-n. Under such conditions that the output values differ by n times, the output values of the individual current detecting means 40-1 to 40-n are multiplied by n in order to enable switching by the operation switching means 50-1 to 50-n. Alternatively, the gain itself of the individual current detecting means 40-1 to 40-n may be multiplied by n.

FIG. 8 shows an operation example of the second embodiment of FIG. For the sake of simplicity, the case where there are only two current control power supplies, 10-1 to 10-2, is shown. FIG. 8 shows the operation when the current control power supply 10-1 has a failure among the current control power supplies 10-1 to 10-2 at the time Tf. Similar to FIG. 5, before the time Tf, the current control power supplies 10-1 to 10-2 output the current Io as a whole while sharing the output currents I1 and I2, respectively.

After the time Tf, the output current I1 of the current control power supply 10-1 becomes zero, and the operation is continued by covering the current Io only with the output current I2 of the current control power supply 10-2. However, unlike FIG. 5, in the case of the circuit of FIG. 7, since the individual output currents I1 to In are kept constant, the variation of I1 to In and the time variation do not occur in FIG.

As shown in FIG. 9, the individual current detecting means 40-1 to 40-n can be realized by the shunt resistors R1 to Rn. At this time, by setting the value of the shunt resistors R1 to Rn to n times the shunt resistance Rs, the gain itself of the individual current detecting means 40-1 to 40-n can be multiplied by n.

Further, as described above, when the current control power supplies 10-1 to 10-n are all normal, the relationship I1 = I2 = ... = In = Io / n is established, and the current detecting means 30-1 to 30-n The output value of is n times the output value of the individual current detecting means 40-1 to 40-n.
Further, when any of the current control power supplies 10-1 to 10-n cannot output the current due to a failure, the output value of the current detection means 30-i is the individual current detection in the normal current control power supply 10-i. It is smaller than n times the output value of the means 40-i. For example, if one current control power supply fails and the current cannot be output, the current is multiplied by (n-1).

Therefore, if the minimum value circuit (MIN) is used as the operation switching means as shown in FIG. 9, the value n times the output value of the individual current detecting means 40-1 to 40-n and the current detecting means 30-1 to 30-1 By selecting the smaller value of the output value of 30-n, the desired operation of the operation switching means 50-1 to 50-n (when all the current control power supplies 10-1 to 10-n are normal, the individual current If any of the feedback control and current control power supplies 10-1 to 10-n based on n times the output value of the detection means 40-1 to 40-n cannot output current due to a failure, the current detection means Feedback control) based on the output value of 30-1 to 30-n is possible.

For stable operation, it is desirable that the coefficient to be multiplied by the output value of the individual current detecting means 40-1 to 40-n is a value slightly smaller than n with a margin, (n-ε). During normal operation, stable operation can be performed without momentarily switching to feedback control based on the output value of the current detecting means 30-1 to 30-n due to the influence of noise or the like.

As shown in FIG. 10, the minimum value circuit (MIN) can be configured by operational amplifiers Qa and Qb, diodes Da and Db, and a pull-up resistor Rpu.

FIG. 11 shows an operation example in the case of the circuit diagram of FIG. For the sake of simplicity, the case of only two current control power supplies 10-1 to 10-2 is shown. The figure shows the operation when the current control power supply 10-1 has a failure among the current control power supplies 10-1 to 10-2 at time Tf. In the figure, the output of the current detecting means 30-2 is shown by a broken line, the output of the individual current detecting means 40-2 is shown by a dashed line, and the output of the minimum value circuit (MIN) is shown by a solid line.

In FIG. 11, as in the case of FIGS. 5 and 8, before the time Tf, the current control power supplies 10-1 to 10-2 output the current Io as a whole while sharing the output currents I1 and I2, respectively. .. At this time, the operation switching means 50-2, which is the minimum value circuit (MIN), is n times (preferably n-ε times) the output of the individual current detecting means 40-1 which is smaller than the output of the current detecting means 30-1. However, n = 2) is selected to cause the current control power supply 10-2 to perform feedback control.

After the time Tf, the output current I1 of the current control power supply 10-1 becomes zero, and the operation is continued by covering the current Io only with the output current I2 of the current control power supply 10-2. At this time, the operation switching means 50-2, which is the minimum value circuit (MIN), selects the current detecting means 30-1 reduced due to the failure of the current control power supply 10-1, and causes the current control power supply 10-2 to perform feedback control. Io is increased by feedback control to suppress the decrease.

FIG. 12 is a circuit diagram of Example 3 in which a short-circuit failure countermeasure is taken for an element that allows a current to flow in only one direction constituting the current synthesis means 20, specifically, diodes D1 and Dn. In FIG. 12, the diodes D11 and Dn1 are inserted in series in preparation for a short-circuit failure of the diodes D1 and Dn, respectively. According to this embodiment, even if a ground fault of the output terminal of the current control power supply 10-1 to 10-n occurs in addition to the short-circuit failure of the diodes D1 and Dn, the normal current control power supply 10-1 to 1 to 1 An output current of 10-n can be supplied to the load RL.

Further, by adding the test voltage dividing resistors R11, R12, Rn1 and Rn2 and adding the test points TP1 to TPn, it becomes possible to detect the failure of the diodes D11 and Dn1.
For example, when testing the diode D11, by stopping the operation of the current control power supply 10-1, if the diode D11 is normal, the test point TP1 has another current control power supply 10-2 to 10-n. A voltage whose output voltage Vo is divided into R12 / (R12 + R11) is observed. If the diode D11 is short-circuited, the output voltage Vo is observed, and if the diode D11 is broken, a voltage of almost 0 V is observed.

According to the present implementation, as described above, in addition to the short-circuit failure of the diodes D1, Dn, the diodes D1 and Dn, due to multiple failures such as a ground fault of the output terminal of the current control power supply 10-1 to 10-n. Failure can be detected before the output current cannot be supplied to the load RL.

13 and 14 are examples in which the current detecting means 30-1 to 30-n are obtained by adding the outputs of the individual current detecting means 40-1 to 40-n.

In FIG. 14, the individual current detecting means 40-1, 40-n are shown by a thin broken line, and the current detecting means 30-1, 30-n are shown by a thick alternate long and short dash line. This is a circuit in which the voltage across the common shunt resistors R1 and Rn is input to the operational amplifiers Q11 to Q1n to Qn1 to Qnn via the resistor Ri. Since the resistor Ri is connected in series to the input terminal of each operational amplifier, it does not affect the failure of any of the individual current detecting means 40-1 to 40-n after the resistor Ri, and is single. It does not become a failure point.

It is also possible to connect a plurality of resistors Ri in series in preparation for a short-circuit failure of the resistors Ri. The function of adding the outputs of the individual current detecting means 40-1 to 40-n can also be realized by an adding circuit using an operational amplifier.

As shown in FIGS. 7 to 13, a method for equivalently realizing the current detecting means 30-1 to 30-n by adding the outputs of the individual current detecting means 40-1 to 40-n as described above is shown in FIGS. 7 to 13. Feedback control is performed not only by the detection results of the individual current detecting means 40-1 to 40-n, but also by the detection results of the current detecting means 30-1 to 30-n as shown in FIGS. 1 to 6. It can also be applied to an embodiment and an embodiment of a standby redundant configuration as shown in FIG.

Further, in this embodiment, since the current detecting means 30-1 to 30-n can be eliminated, the current combining means 20 is loaded with the current combining means 20 even when the current Io is supplied to the load RL distant from a long distance. It can be easily placed at a long distance from.

In FIG. 15, when the output of any of the current control power supplies 10-1 to 10-n is stopped, the operation switching means 50-1 to 50-n obtain the gain of the individual current detecting means 40-1 to 40-n. It is a circuit diagram for switching.
When all of the current control power supplies 10-1 to 10-n are normal, each current control power supply may supply a current of Io / n, but among the current control power supplies 10-1 to 10-n. If one current control power supply fails to supply current, the other current control power supply must supply Io / (n-1) current.

For that purpose, the gain of the individual current detecting means 40-1 to 40-n may be switched to (n-1) / n times. Further, when n = 2, the gain of the individual current detecting means 40-1 to 40-n is halved. At this time, the individual current detecting means 40-1 to 40-n is the current detecting means 30-1. It can also be considered to play a role of ~ 30-n.

In FIG. 15, the operation switching means 50-1 is composed of a P-channel MOSFET, the control terminal (gate) is connected to the output of the current control power supply 10-2, and the output of the current control power supply 10-2 is supplied. When it is turned off, the individual current detecting means 40-1 detects the current by the shunt resistor Rs. When the output of the current control power supply 10-2 is not supplied, the control terminal (gate) is turned on and the individual current detecting means 40-1 detects the current by the shunt resistor Rs / 2. That is, it operates as the individual current detecting means 40-1.

Similarly, the operation switching means 50-2 is composed of a P-channel MOSFET, the control terminal (gate) is connected to the output of the current control power supply 10-1, and the output of the current control power supply 10-1 is supplied. When it is, it is turned off and the individual current detecting means 40-2 detects the current by the shunt resistor Rs. When the output of the current control power supply 10-1 is not supplied, the control terminal (gate) is turned on and the individual current detecting means 40-2 detects the current by the shunt resistor Rs / 2 and operates as the individual current detecting means 40-2. To do.

In FIG. 16, the current combining means 20-1 and 20-n connect the first terminal of the directional element in which the current flows only in the direction from the first terminal to the second terminal, respectively, with the current control power supplies 10-1 to 10-1. Connect the second terminal to the current output terminal on the positive side of 10-n and the current output terminal on the negative side of each current control power supply 10-1 to 10-n, and connect the current control power supply 10-1 to 10 to each. It is a circuit diagram in which −n is connected in series.

According to the sixth embodiment, when any one of the current control power supplies 10-1 to 10-n cannot supply the current due to a failure, the current synthesis means 20-1 to 20-n is used to connect the other current control power supply. It is possible to bypass the output current and supply it as the output current Io.

Here, since the current control power supplies 10-1 to 10-n are connected in series, the current output terminal on the negative side of the current control power supplies 10-1 to 10-n must be insulated from the chassis.
Further, according to this embodiment, since the current control power supplies 10-1 to 10-n are connected in series, the same current flows, but the shared voltage varies in the component constants of the current control power supplies 10-1 to 10-n. It is possible that there will be some variation.

In order to alleviate the instability due to such variation, it is also possible to connect the ballast resistor Rb in parallel with the current control power supply 10-1 to 10-n as shown in FIG.

18 and 19 are circuit diagrams in the case of configuring standby redundancy. In this case, of the current control power supplies 10-1 to 10-n, the current control power supply 10-n is the main system and the current control power supply 10-1 is the standby system. The main system, the current control power supply 10-n (n ≠ 1), controls its own output current In so as to be a target value based on the current detection value of the individual current detection means 40-n.

The current control power supply 10-1 which is a standby system controls its own output current I1 so as to be a target value based on the current detection value of the current detection means 30-1. The pseudo load 60-n for inspection is connected to the output side of the individual current detecting means 40-n in the subsequent stage of the current control power supply 10-n, which is the main system.

In this embodiment, since the output current I1 of the current control power supply 10-1 which is the standby system is 0 during normal operation, a current is passed through the inspection pseudo load 60-n in preparation for a failure, and the current control power supply 10- Diagnose the normality of 1. Assuming that the current flowing through the pseudo load 60-n for inspection is Idummy, a current smaller than the output current In from the main current control power supply 10-n flows into the output current Io.

Therefore, the current control power supply 10-1, which is a standby system, passes a current of I1 = Idummy to compensate for the decrease in the output current Io. As described above, the current control power supply 10-1 can be diagnosed by confirming the operation of the standby system current control power supply 10-1 supplementing the current flowing through the inspection pseudo load 60-n. ..

FIG. 19 is a circuit diagram showing a configuration example of a pseudo load 60-n for inspection. By applying a voltage called Vin to the base of the transistor Tr to which the resistor R is connected to the emitter,
Idummy = (Vin − Vbe) R
However, a test current called Vbe: base-emitter junction potential can be passed.

FIG. 20 is a system configuration diagram of a sensor system using the redundant constant current power supply provided by the present invention. The output current Io from the redundant constant current power supply provided by the present invention is supplied to the sensor 200, and the sensor 200 operates by the supplied current Io to output the sensor output Sout and the signal processing units 300-1 to 300-. It is input to n.

The signal processing units 300-1 to 300-n perform predetermined processing and operation based on the input sensor output Sout. When the current Io supplied from the power supply and the sensor output Sout are transmitted over a long distance as shown in FIG. 20, it is effective to lay a multi-core cable 210 in order to reduce the laying cost and maintenance cost. is there. Further, in order to mitigate the influence of the voltage drop caused by the resistance of the cable 210, it is effective to supply the power supply in a current loop by a constant current power supply.

Further, it is desirable that the sensor output Sout is also output in a current loop by a current source as shown in FIG. In this case, a constant voltage is supplied to the internal circuit of the sensor 200 by connecting the supplied constant current to the shunt regulator or the Zener diode inside the sensor 200.

When the sensor output Sout detected by the sensor 200 is related to the safety and reliability of the system, as shown in FIG. 20, the redundant current control power supply 10-1 to 10-n provided by the present invention is redundant. It is effective to supply power with a constant current power supply. Further, it is desirable that the signal processing unit is also made redundant with 300-1 to 300-n.

In this embodiment, as an example, an example using a redundant constant current power supply that feedback-controls based on the detection results of the current detecting means 30-1 to 30-n shown in FIGS. 1 to 6 is shown. As shown in FIGS. 7 to 13, a redundant constant current power supply that feedback-controls based on the detection results of the individual current detecting means 40-1 to 40-n, and a redundant constant current power supply having a standby redundant configuration as shown in FIG. It goes without saying that it can be used.

When the sensor output Sout detected by the sensor 200 as described above is used to maintain the safety and reliability of the system, the sensor 200 is installed adjacent to the railway track 100 as shown in FIG. As a result, it is possible to determine from the sensor output Sout whether or not a train is present in the section (blocked section) on the railway track. In Japan, a track circuit for detecting a short circuit of a wheel with a current flowing through a line is widely used as a sensor 200 for such an application, and each track circuit corresponds to a block section.

Further, in Europe, an axle sensor that detects the passage of a wheel flange by a change in magnetic flux is widely used as a sensor 200. Axle (axle) sensors are attached to both ends of the block section as sensors 200, and the signal processing units 300-1 to 300-n, called evaluators, determine the train presence status from the number of axles that have entered the block section and the number of axles that have advanced. It is called an axle counter because it is managed.

In such an application, among the redundant signal processing units 300-1 to 300-n, a plurality of signal processing units (signal processing units 300-1 to 300-2 in the embodiment of FIG. 20) are safe side signals ( The safety of the system can be ensured by outputting the safety side signal 320 by the AND circuit 310 only when the signal indicating that there is no train in the closed section) is output. In train control, it is used to detect the train position, control the signal, and control the interlock that permits the operation of the switch, depending on the presence or absence of this safety side signal.

Further, together with the safety side signal 320, the safety side signal 321 of the AND circuit 311 of the safety side signal of another set of signal processing units (signal processing units 300- (n-1) to 300-n in the embodiment of FIG. 20) is used. The availability as a system can be improved by inputting to the OR circuit 312 and obtaining the safe side signal 322. In addition, the availability of the system can be improved by taking a majority vote of the outputs of a plurality of signal processing units.

In particular, in the suburbs of metropolitan areas and railways that serve as trunk lines, high-density transportation is required at short train intervals. High reliability and improved availability are extremely important. In addition, in order to apply the axle counter, which is widely used in Europe, to the suburbs of metropolitan areas and railways on trunk lines, the constant current power supply is made redundant and the signal processing unit (evaluator) is shown in this example. It is extremely important to improve reliability and availability through redundancy and OR connection.

Needless to say, it is desirable that the AND circuits 310 and 311 and the OR circuit 312 be realized by circuits that utilize one-sided failure characteristics such as fail-safe AND and relays that use alternating signals that are widely used in the railway field. Is.

FIG. 21 shows an example in which the current output of the current control power supply 10-1 to 10-n is transmitted by individual wiring of the cable 210 and combined with the current Io by the current combining means 20 placed near the sensor 200. .. According to this embodiment, the path for supplying power to the sensor 200 can also be made redundant, and the reliability of power supply can be further improved.

In this embodiment, a method is used in which the current detecting means 30-1 to 30-n are equivalently realized by adding the outputs of the individual current detecting means 40-1 to 40-n shown in FIG. There is. Therefore, the current detecting means 30-1 to 30-n is not required after the current combining means 20, and the current detection result by the current detecting means 30-1 to 30-n is output again via the long cable 210 to the current control power supply 10. There is no need to return to -1 to 10-n.

Here, it has been shown that the embodiment of FIG. 13 is used as an example, but the current detecting means 30-1 to 30- by adding the outputs of the individual current detecting means 40-1 to 40-n shown in FIG. An example in which feedback control is performed based on the detection results of the current detecting means 30-1 to 30-n as shown in FIGS. 1 to 6 by applying a method for equivalently realizing n, and as shown in FIG. It is also possible to apply the example of the standby redundant configuration to this embodiment. The current combining means 20 may be built in the sensor 200.
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist of the present invention.

10-1 to 10-n ... Current control power supply, 20 ... Current synthesis means,
30-1 to 30-n ... Current detecting means, 40-1 to 40-n ... Individual current detecting means,
50-1 to 50-n ... Operation switching means, 200 ... Sensor, 210 ... Cable,
300-1 to 300-n ... Signal processing unit

Claims (15)

With multiple current control power supplies that can control the output current,
A current synthesizing means for synthesizing the current outputs of the plurality of current control power supplies,
Each current control power supply has a current detecting means for detecting the output current in the subsequent stage of the current combining means.
A redundant constant current power supply that controls the output current detected by the current detecting means so as to reach the total current target value. The redundant constant current power supply according to claim 1.
The current synthesizing means is composed of a plurality of directional elements that allow current to flow only in the direction from the first terminal to the second terminal.
The first terminals of the plurality of directional elements are each connected to the current output terminals of the plurality of current control power supplies.
A redundant constant current power supply characterized in that the second terminals of the plurality of directional terminals are connected in parallel at one point. The redundant constant current power supply according to claim 2.
A redundant constant current power supply characterized in that the directional element is a diode. The redundant constant current power supply according to claim 1.
Each of the individual current control power supplies has an individual current detection means for detecting the output current of the current control power supply, and each current control power supply has an operation switching means.
The operation switching means controls the output of the individual current detecting means so as to be an individual current target value when all the current control power supplies are normal.
When any of the current control power supplies is abnormal, the redundant constant current is controlled so that the total output of the individual current detection means becomes the total current target value. Power supply. The redundant constant current power supply according to claim 4.
When n of the current control power supplies are provided, the operation switching means sets the first value obtained by multiplying the output of the individual current detecting means by n and the minimum value among the outputs of the current detecting means as the current detection value. ,
A redundant constant current power supply characterized in that the current detection value is controlled to be n times the individual current target value. The redundant constant current power supply according to claim 5.
The individual current detecting means comprises a resistor.
The individual current detecting means and the means for multiplying the output of the individual current detecting means by n
A redundant constant-current power supply characterized by comprising a resistor having a resistance value n times that of the resistor in the current detecting means. The redundant constant current power supply according to claim 2.
A redundant constant-current power supply characterized in that a plurality of the directional elements are connected in series. The redundant constant current power supply according to claim 7.
A redundant constant-current power supply characterized in that a current voltage dividing resistor is connected in parallel to at least one of the directional elements connected in series by two. The redundant constant current power supply according to claim 1.
A redundant constant current power supply, wherein the current detecting means is realized by an output addition function of the individual current detecting means. The redundant constant current power supply according to claim 4.
When there are n current control power supplies, the operation switching means sets the gain of the individual current detection means to (n-1) / n when the output of any of the plurality of current control power supplies is stopped. Redundant constant current power supply featuring double switching. The redundant constant current power supply according to claim 1.
The current synthesizing means connects the first terminal of the directional element that allows current to flow only in the direction from the first terminal to the second terminal to the current output terminal on the positive side of each of the current control power supplies, and the second terminal. Is connected to the current output terminal on the negative side of each of the current control power supplies.
A redundant constant current power supply, characterized in that the respective current control power supplies are connected in series. The redundant constant current power supply according to claim 1.
A redundant constant current power supply, characterized in that a pseudo load for inspection is connected to any of the current control power supplies. The redundant constant current power supply according to claim 1 and
With the sensor
A sensor system characterized by having a signal processing unit that operates by a signal from a sensor. The sensor system according to claim 13.
The sensor detects the train axle and
The signal processing unit is a sensor system characterized in that it determines the existence of a train in a specific section of a railroad track. The sensor system according to claim 13.
A sensor system characterized in that the signal processing unit has a redundant configuration.

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