An electronic switching circuit and track circuit

Abstract

The application discloses an electronic switch circuit and a track circuit. The electronic switch circuit comprises a first interface, a second interface, a switch module, a protection module and a relay control interface; the first interface is connected with a positive power receiving end of a first steel rail; the second interface is connected with a negative power receiving end of a second steel rail; the switch module is connected with the first interface, the second interface and the relay control interface respectively, and the switch module is used for controlling the on-off between the second interface and the relay control interface according to the relative relationship between the voltage value of the first interface and a first preset range; the protection module is connected with the first interface and the switch module respectively, and the protection module is used for controlling the disconnection between the switch module and the relay control interface in the case of short circuit between the first steel rail and the second steel rail, and if the switch module has a short circuit fault. The application can improve the reliability of the electronic switch circuit and the safety of the track.

Description

Technical Field

[0001] The embodiments of the present invention relate to signal indication technology, and more particularly to an electronic switch circuit and a track circuit. Background Technology

[0002] Track circuits are widely used on various locomotive tracks to detect whether the rails are free and send corresponding signals to collect information on track occupancy.

[0003] Reference Figure 1 The core of a traditional DC electronic switch-type track circuit is an electronic switch circuit. The control part of this electronic switch circuit controls the state of the track relay by switching the on and off of a transistor.

[0004] However, this type of electronic switchboard circuit is often installed outdoors, making it prone to short circuits. The track relay is constantly engaged and cannot reflect track occupancy information, resulting in low reliability. Summary of the Invention

[0005] This invention provides an electronic switch circuit and a track circuit to improve the reliability of the electronic switch circuit and the safety of the track.

[0006] In a first aspect, embodiments of the present invention provide an electronic switch circuit. The electronic switch circuit is applied to a track circuit, which includes a first rail, a second rail, a first power supply, a track relay, the electronic switch circuit, and a second power supply; the positive terminal of the first rail is connected to the positive terminal of the first power supply, and the negative terminal of the second rail is connected to the negative terminal of the first power supply; one end of the track relay is connected to the positive terminal of the second power supply, and the negative terminal of the second power supply is connected to the negative terminal of the second rail.

[0007] The electronic switch circuit includes: a first interface, a second interface, a switch module, a protection module, and a relay control interface;

[0008] The first interface is connected to the positive power receiving end of the first rail; the second interface is connected to the negative power receiving end of the second rail.

[0009] The switch module is connected to the first interface, the second interface and the relay control interface respectively. The switch module is used to control the connection and disconnection between the second interface and the relay control interface according to the relative relationship between the voltage value of the first interface and a first preset range.

[0010] The protection module is connected to the first interface and the switch module respectively. The protection module is used to disconnect the connection between the switch module and the relay control interface if a short circuit fault occurs in the switch module in the event of a short circuit between the first rail and the second rail.

[0011] Optionally, the switch module includes: a signal output terminal, a first negative terminal, and a first control terminal. The signal output terminal is connected to the relay control interface, the first negative terminal of the switch module is connected to the second interface, and the first control terminal of the switch module is connected to the first interface. The switch module is used to control the signal output terminal and the first negative terminal to be turned off when the voltage value of the first interface is outside the first preset range.

[0012] Optionally, the electronic switch circuit further includes an auxiliary power supply port, which is connected to the positive terminal of the first power supply;

[0013] The protection module includes: a first overcurrent protection device, a protection circuit, a power supply terminal, a protection terminal, a first sampling terminal, and a second sampling terminal. The first overcurrent protection device is connected between the signal output terminal and the relay control interface. The power supply terminal is connected to the auxiliary power supply interface. The protection terminal is connected to the relay control interface. The first sampling terminal and the second sampling terminal are respectively connected to the first interface and the second interface. The protection circuit is used to delay the conduction of the power supply terminal and the protection terminal when the voltage difference between the first sampling terminal and the second sampling terminal is outside the first preset range. The current input to the auxiliary power supply interface is greater than the protection current of the first overcurrent protection device.

[0014] Optionally, the protection module includes a protection unit and a delay unit. The protection unit includes a first switching transistor, with a first end of the first switching transistor serving as the power supply terminal and a second end of the first switching transistor serving as the protection terminal.

[0015] The delay unit includes a second switch, a first capacitor, and a first resistor. The first capacitor and the first resistor are connected in parallel between the two ends of the second switch. The control terminal of the second switch serves as the first sampling terminal. The first end of the second switch is connected to the control terminal of the first switch, and the second end of the second switch serves as the second sampling terminal.

[0016] Optionally, the switching module includes: a third switching transistor, a second resistor, and a second capacitor. The first terminal of the third switching transistor serves as the signal output terminal, the second terminal of the third switching transistor serves as the first negative terminal, the control terminal of the third switching transistor serves as the first control terminal, and the second resistor and the second capacitor are connected in parallel between the control terminal and the second terminal of the third switching transistor.

[0017] Optionally, the protection unit further includes a second overcurrent protection device and a fifth resistor. The second overcurrent protection device is connected between the power supply terminal and the auxiliary power supply port, and the fifth resistor is connected between the first terminal of the first switching transistor and the control terminal. The protection current of the second overcurrent protection device is greater than the protection current of the first overcurrent protection device.

[0018] Optionally, the switching module further includes: a third diode, the anode of the third diode being connected to the control terminal of the third switching transistor, and the connection point of the second capacitor and the second resistor being connected to the cathode of the third diode;

[0019] The delay unit further includes a fourth diode, which is connected between the first terminal of the second switching transistor and the first capacitor; the third and fourth diodes are used to prevent the capacitor from reverse discharging.

[0020] Optionally, the electronic switch circuit further includes a voltage regulator module, which is connected between the first interface and the second interface and is used to stabilize the voltage between the first interface and the second interface at a preset value.

[0021] Optionally, the voltage regulator module includes: at least one first diode and a second diode, wherein at least one first diode is connected in series between the first interface and the second interface; and the second diode is connected in series between the first interface and the second interface, with the connection direction opposite to that of the first diode.

[0022] Secondly, embodiments of the present invention also provide a track circuit, the track circuit including any electronic switch circuit described in the first aspect, a first rail, a second rail, a first power supply, a track relay, and a second power supply;

[0023] The positive power supply terminal of the first rail is connected to the positive terminal of the first power supply, and the negative power supply terminal of the second rail is connected to the negative terminal of the first power supply; one end of the track relay is connected to the positive terminal of the second power supply, and the negative terminal of the second power supply is connected to the negative power supply terminal of the second rail.

[0024] The first interface of the electronic switch circuit is connected to the positive power receiving end of the first rail; the second interface of the electronic switch circuit is connected to the negative power receiving end of the second rail; and the auxiliary power supply interface of the electronic switch circuit is connected to the positive terminal of the first power supply.

[0025] The electronic switch circuit and track circuit provided in this embodiment are equipped with a switch module, a protection module, and a relay control interface. The switch module can control the connection and disconnection between the second interface and the relay control interface based on the voltage value of the first interface. The protection module can collect the voltage of the first interface. If the voltage of the first interface is outside a first preset range, it can determine the state of the switch module. If the switch module is still conducting, the protection module controls the connection between the switch module and the relay control interface to disconnect, so that the track relay can indicate occupancy. This realizes error correction for short circuit fault indication and prevents the track relay from only indicating no occupancy due to a short circuit fault. During a short circuit fault, since the track relay always indicates occupancy, no locomotive will accidentally enter, thus improving the reliability of the electronic switch circuit and the safety of the track. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of a track circuit in the prior art;

[0027] Figure 2 A schematic diagram of a track circuit provided in an embodiment of the present invention;

[0028] Figure 3 A circuit diagram of another track circuit provided in an embodiment of the present invention;

[0029] Figure 4 A circuit diagram of yet another track circuit provided in an embodiment of the present invention;

[0030] Figure 5 This is a circuit diagram of another track circuit provided in an embodiment of the present invention. Detailed Implementation

[0031] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and not intended to limit it. Furthermore, it should be noted that, for ease of description, the accompanying drawings show only the parts relevant to the present invention, and not all of the structures.

[0032] As described in the background section, existing track circuits use electronic switching circuits to control the switching on or off of transistors based on whether there is a short circuit between two tracks (a short circuit corresponds to a locomotive on the track, and no short circuit corresponds to no locomotive on the track). This, in turn, controls the dropping or picking up of track relays to indicate track occupancy. However, electronic switching circuits are generally located in junction boxes next to open-air tracks, making them susceptible to damage from extreme weather. The inventors have discovered that transistors in electronic switching circuits have a chance of short-circuiting during extreme weather events such as lightning strikes. If a transistor short-circuits or a negative charge is introduced into the positive terminal, the track relay will remain in the energized state. Even if a locomotive occupies the corresponding track section, the track relay will not drop, still displaying a "no locomotive" signal, failing to reflect the occupancy information of that track section, posing a safety hazard.

[0033] To address the aforementioned problems, embodiments of the present invention provide an electronic switching circuit. Figure 2 This is a schematic diagram of a track circuit provided in an embodiment of the present invention, with reference to... Figure 2 The track circuit 100 includes a first rail 101, a second rail 102, a first power supply V1, a track relay 103, an electronic switch circuit 104, and a second power supply V2. The positive terminal a+ of the first rail 101 is connected to the positive terminal of the first power supply V1, and the negative terminal a- of the second rail 102 is connected to the negative terminal of the first power supply V1. One end of the track relay 103 is connected to the positive terminal of the second power supply V2, and the negative terminal of the second power supply V2 is connected to the negative terminal a- of the second rail 102.

[0034] The electronic switch circuit 104 includes: a first interface c, a second interface d, a switch module 105, a protection module 106, and a relay control interface e. The first interface c is connected to the positive power receiving terminal b+ of the first rail 101; the second interface d is connected to the negative power receiving terminal b- of the second rail 102. The switch module 105 is connected to the first interface c, the second interface d, and the relay control interface e, respectively. The switch module 105 controls the connection between the second interface d and the relay control interface e based on the voltage value of the first interface c. The protection module 106 is connected to the first interface c and the switch module 105, respectively. The protection module 106 disconnects the connection between the switch module 105 and the relay control interface e if the voltage of the first interface c is outside a first preset range and a short circuit fault occurs in the switch module 105.

[0035] Specifically, the first power supply V1 is a power source that can supply power to the rails and can be installed in a power supply box on the side of the track section's power supply end. The positive and negative terminals of the first power supply V1 are connected to the positive power supply terminal a+ of the first rail 101 and the negative power supply terminal a- of the second rail 102, respectively. A current-limiting resistor can also be installed between the positive terminal of the first power supply V1 and the first rail 101 to limit the current level on the rails and ensure the safety of rail power supply. The second power supply V2 is a power source that can supply power to the track relay 103 and can be installed in the relay room. The positive terminal of the second power supply V2 is connected to the track relay 103, and the negative terminal of the second power supply V2 is connected to the negative power supply terminal a- of the second rail 102. One end of the track relay 103 is connected to the second power supply V2, and the other end of the track relay 103 is connected to the relay control interface e of the electronic switch circuit 104, allowing it to be activated or deactivated according to the signal from the relay control interface e.

[0036] The first interface c of the electronic switch circuit 104 is connected to the positive power receiving terminal b+ of the first rail 101, that is, connected to the positive terminal of the first power supply V1 via the first rail 101. The second interface d of the electronic switch circuit 104 is connected to the negative power receiving terminal b- of the second rail 102, that is, connected to the negative terminals of the first power supply V1 and the second power supply V2 via the second rail 102. When there is no locomotive on the first rail 101 and the second rail 102, the voltage level of the first interface c is within a first preset range. When there is a locomotive on the first rail 101 and the second rail 102, a short circuit occurs between the first rail 101 and the second rail 102, and the voltage of the first interface c is outside the first preset range. The switch module 105 can control the connection and disconnection between the second interface d and the relay control interface e according to the voltage value of the first interface c. When there is no locomotive on the rails, the voltage value of the first interface c is within the first preset range. Switch module 105 is turned on, connecting the second interface d to the relay control interface e. Thus, the two ends of track relay 103 are connected to the positive and negative terminals of the second power supply V2, forming a complete circuit. At this time, track relay 103 is activated, indicating that the track section is not occupied by a locomotive. When there is a locomotive on the rails, the voltage value of the first interface c is outside the first preset range. Switch module 105 is turned off, disconnecting the second interface d from the relay control interface e. Thus, only one end of track relay 103 is connected to the positive terminal of the second power supply V2, not forming a complete circuit. At this time, track relay 103 is deactivated, indicating that the track section is occupied by a locomotive. Protection module 106 is connected to the first interface c and can collect the voltage of the first interface c. Protection module 106 is also connected to the auxiliary power supply interface and switch module 105. When the voltage of the first interface c is simultaneously detected to be outside the first preset range, protection module 106 can determine whether switch module 105 is turned on. If switch module 105 is conducting at this time, it indicates that a short circuit fault has occurred in switch module 105. Protection module 106 then disconnects the line connection between switch module 105 and relay control interface e, ensuring that track relay 103 drops to indicate that the track section is occupied, thus preventing incorrect indications caused by short circuit damage to switch module 105. The control line can be disconnected by installing a controllable circuit breaker, controllable switch, or any other controllable switching device between switch module 105 and relay control interface e. After protection module 106 disconnects the line connection between switch module 105 and relay control interface e, track relay 103 will remain dropped to indicate track section occupancy. If the on-duty personnel find the track section occupancy signal to be prolonged, they will investigate the fault and repair the circuit. During this period, because track relay 103 continuously indicates occupancy, no locomotive will accidentally enter, improving track safety.

[0037] The electronic switch circuit provided in this embodiment includes a switch module, a protection module, and a relay control interface. The switch module can control the connection and disconnection between the second interface and the relay control interface based on the voltage value of the first interface. The protection module can collect the voltage of the first interface. If the voltage of the first interface is outside a first preset range, it can determine the state of the switch module. If the switch module is still conducting, the protection module controls the connection between the switch module and the relay control interface to disconnect, so that the track relay can indicate occupancy. This achieves error correction for short-circuit fault indication and prevents the track relay from only indicating no occupancy due to a short-circuit fault. During a short-circuit fault, since the track relay always indicates occupancy, no locomotive will accidentally enter, thus improving the reliability of the electronic switch circuit and the safety of the track.

[0038] Optionally, Figure 3 A circuit diagram of another track circuit provided in an embodiment of the present invention is shown below. Figure 3 Based on the aforementioned embodiments, the switch module 105 includes: a signal output terminal f, a first negative terminal g, and a first control terminal h. The signal output terminal f is connected to the relay control interface e. The first negative terminal g of the switch module 105 is connected to the second interface d. The first control terminal h of the switch module 105 is connected to the first interface c. The switch module 105 is used to control the signal output terminal f and the first negative terminal g to turn off when the voltage value of the first interface c is outside a first preset range.

[0039] The electronic switch circuit 104 also includes an auxiliary power supply port m, which is connected to the positive terminal of the first power supply V1. The protection module 106 includes: a first overcurrent protection device 201, a protection circuit 202, a power supply terminal i, a protection terminal j, a first sampling terminal k, and a second sampling terminal l. The first overcurrent protection device 201 is connected between the signal output terminal f and the relay control interface e. The power supply terminal i is connected to the auxiliary power supply interface, and the protection terminal j is connected to the relay control interface e. The first sampling terminal k and the second sampling terminal l are respectively connected to the first interface c and the second interface d. The protection circuit 202 is used to delay the conduction of the power supply terminal i and the protection terminal j when the voltage difference between the first sampling terminal k and the second sampling terminal l is outside a first preset range. The current input to the auxiliary power supply interface is greater than the protection current of the first overcurrent protection device 201.

[0040] Specifically, when the voltage at the first control terminal h is within a first preset range, the switch module 105 can connect the signal output terminal f to the first negative terminal g; when the voltage at the first control terminal h is outside the first preset range, the switch module 105 can disconnect the signal output terminal f from the first negative terminal g. The first overcurrent protection device 201 is connected between the signal output terminal f and the relay control interface e. It can disconnect based on the relative relationship between its own current and a preset protection current, thus achieving overcurrent protection. The protection current is the maximum current that the overcurrent protection device can withstand. When the current flowing through the overcurrent protection device exceeds the protection current, the overcurrent protection device disconnects. The power supply terminal i of the protection module 106 is connected to the auxiliary power supply port m, and the protection terminal j is connected to the relay control interface e. The first overcurrent protection device 201 can be a fuse.

[0041] For example, when the voltage difference between the first sampling terminal k and the second sampling terminal l is outside a first preset range, the protection module 106 can control the power supply terminal i to connect with the protection terminal j, directly outputting the current provided by the auxiliary power supply terminal i to the relay control interface e. If the switch module 105 experiences a short circuit fault, the current provided by the auxiliary power supply terminal i will pass through the first overcurrent protection device 201 and the switch module 105, causing the first overcurrent protection device 201 to disconnect. Thus, the track relay 103 can drop to indicate track section occupancy. Maintaining the track relay 103 to indicate track section occupancy in the event of a switch module 105 fault prevents other locomotives from passing through the section, thus preventing collisions caused by short circuit faults in the switch module 105 and improving the reliability of the electronic switch circuit 104.

[0042] Optionally, Figure 4 A circuit diagram of another track circuit provided in an embodiment of the present invention is shown below. Figure 4 Based on the aforementioned embodiments, the electronic switch circuit 104 further includes a voltage regulator module 301, which is connected between the first interface c and the second interface d and is used to stabilize the voltage between the first interface c and the second interface d within a first preset range.

[0043] Specifically, the voltage regulator module 301 may include a voltage regulator circuit. When there is no short circuit between the first rail 101 and the second rail 102, the voltage regulator circuit can control the voltage between the first interface c and the second interface d to remain stable within a first preset range, which can further improve the stability of the electronic switch circuit 104.

[0044] Optionally, Figure 5 A circuit diagram of another track circuit provided in an embodiment of the present invention is shown below. Figure 5Based on the aforementioned embodiments, the voltage regulator module 301 includes: at least one first diode D1 and a second diode D2, wherein the at least one first diode D1 is connected in series between the first interface c and the second interface d. The second diode D2 is connected in series between the first interface c and the second interface d, with the connection direction opposite to that of the first diode D1.

[0045] Specifically, the first diode D1 in the voltage regulator module 301 is a Zener diode. The voltage regulator module 301 can use two IN5408 first diodes D1 to achieve a voltage regulation of 1.4V. When there is no short circuit between the first rail 101 and the second rail 102, the first diode D1 limits the voltage difference between the first interface c and the second interface d to a first preset range, which can be no less than 1.4V. The second diode D2 in the voltage regulator module 301 is a reverse connection protection diode, connected between the first interface c and the second interface d, with the connection direction opposite to that of the first diode D1, preventing reverse connection of the positive and negative terminals of the first rail 101 and the second rail 102, and blocking reverse current bypass.

[0046] For example, when a DC voltage of 4V to 18V is applied between the first interface c and the second interface d, the voltage between the first interface c and the second interface d can be forcibly regulated to 1.4V by two series-connected first diodes D1, thereby turning on the second and third switches. The conduction of the second switch causes the first switch to turn off, and the conduction of the third switch causes the excitation circuit of the track relay 103 to conduct, causing the track relay 103 to be energized and closed. When a DC voltage less than 1.4V is applied between the first interface c and the second interface d (when the locomotive short-circuits the first rail 101 and the second rail 102), even if the two series-connected first diodes D1 have a voltage regulation effect, the voltage value between the first interface c and the second interface d will be much less than 1.4V, thereby causing the third switch to turn off immediately and the second switch to turn off after a delay. The turn-off of the third switch immediately disconnects the excitation circuit of the track relay 103, causing the track relay 103 to drop; the delayed turn-off of the second switch causes the first switch to turn on after a delay.

[0047] Optionally, continue to refer to Figure 5Based on the aforementioned embodiments, the protection module 106 includes a protection unit and a delay unit. The protection unit includes a first switch Q1, with its first terminal serving as a power supply terminal and its second terminal serving as a protection terminal. The delay unit includes a second switch Q2, a first capacitor C1, and a first resistor R1. The first capacitor C1 and the first resistor R1 are connected in parallel between the two ends of the second switch Q2. The control terminal of the second switch Q2 serves as a first sampling terminal, the first terminal of the second switch Q2 is connected to the control terminal of the first switch Q1, and the second terminal of the second switch Q2 serves as a second sampling terminal. The switch module 105 includes a third switch Q3, a second resistor R2, and a second capacitor C2. The first terminal of the third switch Q3 serves as a signal output terminal, the second terminal of the third switch Q3 serves as a first negative terminal, the control terminal of the third switch Q3 serves as a first control terminal, and the second resistor R2 and the second capacitor C2 are connected in parallel between the control terminal and the second terminal of the third switch Q3.

[0048] Specifically, the third switch Q3 of the switch module 105 can be an NPN transistor or other switch that conducts when its control terminal is at a high potential. The third switch Q3 can conduct when the voltage difference between the first interface c and the second interface d is within a first preset range, meaning the voltage at the first interface c is 1.4V higher than the voltage at the second interface d. The third switch Q3 can also be turned off when the voltage difference between the first interface c and the second interface d is outside the first preset range, meaning the voltage at the first interface c is equal to the voltage at the second interface d. The switch module 105 also includes a third resistor R3, a third diode D3, and a fifth diode D5. The anode of the third diode D3 is connected to the control terminal of the third switch Q3 via the fifth diode D5. The connection point of the second capacitor C2 and the second resistor R2 is connected to the cathode of the third diode D3. The second capacitor C2 can be an electrolytic capacitor to ensure that the conduction time of the third switch Q3 is later than the conduction time of the second switch Q2. The second resistor R2 serves as the bleeder resistor for the second capacitor C2. The third diode D3 is an isolation diode, which prevents the charging second capacitor C2 from reverse discharging.

[0049] The first switch Q1 and the second switch Q2 are NPN transistors or other switches that conduct when their control terminals are at a high potential. Similar to the third switch Q3, the second switch Q2 can conduct when the voltage difference between the first interface c and the second interface d is within a first preset range, which means the voltage at the first interface c is 1.4V higher than the voltage at the second interface d. The second switch Q2 can also be turned off when the voltage difference between the first interface c and the second interface d is outside the first preset range, which means the voltage at the first interface c is equal to the voltage at the second interface d. The first switch Q1 can remain off when the second switch Q2 is on. The first switch Q1 can also be turned on when the second switch Q2 is off, using the current input from the auxiliary power supply terminal to detect whether the third switch Q3 has broken down or short-circuited. If so, the current input from the auxiliary power supply terminal will burn out the first overcurrent protection device 201, thus controlling the track relay 103 to fall. The delay unit also includes a fourth resistor R4, a fourth diode D4, and a sixth diode D6. The fourth resistor R4 and the sixth diode D6 are connected in series between the first positive terminal and the control terminal of the second switch Q2. The fourth diode D4 is connected between the first terminal of the second switch Q2 and the first capacitor C1. The first capacitor C1 can be an electrolytic capacitor with a capacitance greater than that of the second capacitor C2, ensuring that the turn-off time of the second switch Q2 is later than that of the third switch Q3. This prevents the first switch Q1 from turning on before the third switch Q3 turns off, thus avoiding accidental burnout of the first overcurrent protection device 201, or prevents the third switch Q3 from turning on before the first switch Q1 turns off, thus preventing circuit damage. The fourth diode D4 is used to prevent reverse discharge of the first capacitor C1. The protection unit also includes a second overcurrent protection device B2 and a fifth resistor R5. The protection current of the second overcurrent protection device B2 is greater than the protection current of the first overcurrent protection device 201, and the fifth resistor R5 can provide a bias voltage.

[0050] For example, when the track section is idle, the voltage at the receiving ends of the first rail 101 and the second rail 102 is normal, that is, the voltage between the first port and the second port is regulated at 1.4V. The 1.4V control voltage can be applied to two control loops: one loop controls the third switch Q3 to conduct, causing the track relay 103 to be energized; the other loop acts on the control terminal of the second switch Q2 through the fourth resistor R4 and the sixth diode D6, causing the second switch Q2 to conduct. After the second switch Q2 is turned on, the potential of its collector is 0, the bias voltage input to the first switch Q1 through the fifth resistor R5 is also 0, the first switch Q1 is turned off, and there is no current output from the emitter of the first switch Q1.

[0051] When a locomotive enters the track section or a fault occurs in the track section, the 1.4V voltage between the first interface c and the second interface d disappears. As can be seen from the circuit, the third switch Q3 immediately turns off, causing the track relay 103 to de-energize and drop. At this time, although the second switch Q2 also turns off simultaneously, and the bias voltage through the fifth resistor R5 begins to recover, due to the charging effect of the first capacitor C1, the bias voltage of the first switch Q1 takes approximately 0.1 seconds to reach its rated value before it turns on, and its emitter begins to output current. This ensures that the third switch Q3 turns off first, and the first switch Q1 turns on later. After the third switch Q3 turns off, the first switch Q1 turns on and outputs current. If the third switch Q3 is damaged and short-circuited, its collector and emitter are connected, and it is also connected to the negative terminal of the first power supply V1, forming a loop in the circuit containing the first switch. The current output by the first switch Q1 when it turns on exceeds the protection current of the first short-circuit protection device, causing the first short-circuit protection device to melt. The excitation circuit of track relay 103 is cut off. When the third switch Q3 is short-circuited, the current flowing through the first switch Q1 is denoted as the first current I1, and the current flowing through track relay 103 is denoted as the second current I2. Then I1+I2 is greater than the protection current of the first fuse.

[0052] Even after the locomotive leaves the track section, track relay 103 still fails to engage. The display device in the relay room can indicate a fault in track circuit 100, ensuring fault-oriented safety. When the positive terminal of the second power supply V2 mixes with negative current from other sections after passing through the coil of track relay 103, the first power supply V1 can melt the first overcurrent protection device 201 in the adjacent section's circuit. The display device in the relay room will then indicate a mixed-wire fault in the adjacent section, preventing track relay 103 from malfunctioning due to mixed-wire and causing incorrect indication signals. The adjacent section displays a fault in track circuit 100, requiring inspection and troubleshooting before restoration, thus also ensuring fault-oriented safety.

[0053] Furthermore, after the locomotive leaves the track section or the fault is resolved, the 1.4V voltage between the first interface c and the second interface d is restored. The second switch Q2 immediately turns on and the first switch Q1 immediately turns off. Due to the charging effect of the third capacitor, the third capacitor always turns on slightly later. The function of the first capacitor C1 and the second capacitor C2 is to prevent the first switch Q1 from outputting current first, burning out the first overcurrent protection device 201, or to prevent the third switch Q3 from turning on before the first switch Q1 turns off, thus preventing circuit damage. The above circuit ensures that the protection unit and the switch module 105 do not conflict with each other and is a very important circuit component.

[0054] The electronic switch circuit proposed in this embodiment allows the switch module to control the connection and disconnection between the second interface and the relay control interface based on the voltage value of the first interface. The protection module can collect the voltage of the first interface and determine the state of the switch module if the voltage of the first interface is outside a first preset range. If the switch module is still conducting, the protection module controls the switch module to disconnect from the relay control interface, enabling the track relay to indicate occupancy. This achieves error correction for short-circuit fault indication and prevents the track relay from only indicating no occupancy due to a short-circuit fault. During a short-circuit fault, since the track relay always indicates occupancy, no locomotive will accidentally enter, thus improving the reliability of the electronic switch circuit and the safety of the track.

[0055] This invention also provides a track circuit. (Continuing to refer to...) Figure 2 The track circuit 100 includes any of the aforementioned electronic switch circuits 104, a first rail 101, a second rail 102, a first power supply V1, a track relay 103, and a second power supply V2. The positive terminal a+ of the first rail 101 is connected to the positive terminal of the first power supply V1, and the negative terminal a- of the second rail 102 is connected to the negative terminal of the first power supply V1. One end of the track relay 103 is connected to the positive terminal of the second power supply V2, and the negative terminal of the second power supply V2 is connected to the negative terminal a- of the second rail 102. The first interface c of the electronic switch circuit 104 is connected to the positive terminal b+ of the first rail 101. The second interface d of the electronic switch circuit 104 is connected to the negative terminal b- of the second rail 102. The auxiliary power supply interface of the electronic switch circuit 104 is connected to the positive terminal of the first power supply V1.

[0056] The electronic switch circuit and track circuit provided in this embodiment of the invention allow the switch module to control the connection and disconnection between the second interface and the relay control interface based on the voltage value of the first interface. The protection module can collect the voltage of the first interface and determine the state of the switch module if the voltage of the first interface is outside a first preset range. If the switch module is still conducting, the protection module controls the switch module to disconnect from the relay control interface, enabling the track relay to indicate occupancy. This achieves error correction for short-circuit fault indication and prevents the track relay from only indicating no occupancy due to a short-circuit fault. During a short-circuit fault, since the track relay always indicates occupancy, no locomotive will accidentally enter, thus improving the reliability of the electronic switch circuit and the safety of the track.

[0057] Note that the above description is merely a preferred embodiment of the present invention and the technical principles employed. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and various obvious changes, readjustments, combinations, and substitutions can be made without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in detail through the above embodiments, the present invention is not limited to the above embodiments, and may include many other equivalent embodiments without departing from the concept of the present invention, the scope of which is determined by the scope of the appended claims.

Claims

1. An electronic switching circuit, characterized in that, This is applied to a track circuit, which includes a first rail, a second rail, a first power supply, a track relay, an electronic switch circuit, and a second power supply. The positive terminal of the first rail is connected to the positive terminal of the first power supply, and the negative terminal of the second rail is connected to the negative terminal of the first power supply. One end of the track relay is connected to the positive terminal of the second power supply, and the negative terminal of the second power supply is connected to the negative terminal of the second rail. The electronic switch circuit includes: a first interface, a second interface, a switch module, a protection module, an auxiliary power supply port, and a relay control interface; The first interface is connected to the positive power receiving end of the first rail; the second interface is connected to the negative power receiving end of the second rail. The switch module is connected to the first interface, the second interface, and the relay control interface respectively. The switch module is used to control the connection and disconnection between the second interface and the relay control interface according to the relative relationship between the voltage value of the first interface and a first preset range. Specifically, the switch module includes: a signal output terminal, a first negative terminal, and a first control terminal. The signal output terminal is connected to the relay control interface, the first negative terminal of the switch module is connected to the second interface, and the first control terminal of the switch module is connected to the first interface. The switch module is used to control the signal output terminal and the first negative terminal to be turned off when the voltage value of the first interface is outside the first preset range. The other end of the track relay is connected to the relay control interface, and the track relay is activated or deactivated according to the signal from the relay control interface. The auxiliary power supply port is connected to the positive terminal of the first power supply. The protection module is connected to the first interface and the switch module respectively. The protection module is used to disconnect the connection between the switch module and the relay control interface if a short circuit occurs between the first rail and the second rail. Specifically, the protection module includes: a first overcurrent protection device, a protection circuit, a power supply terminal, a protection terminal, a first sampling terminal and a second sampling terminal. The first overcurrent protection device is connected between the signal output terminal and the relay control interface. The power supply terminal is connected to the auxiliary power supply port. The protection terminal is connected to the relay control port. The first sampling terminal and the second sampling terminal are connected to the first interface and the second interface respectively. The protection circuit is used to delay the conduction of the power supply terminal and the protection terminal when the voltage difference between the first sampling terminal and the second sampling terminal is outside the first preset range. The current input to the auxiliary power supply port is greater than the protection current of the first overcurrent protection device.

2. The electronic switching circuit according to claim 1, characterized in that, The protection module includes a protection unit and a delay unit. The protection unit includes a first switching transistor, with a first end of the first switching transistor serving as the power supply end and a second end of the first switching transistor serving as the protection end. The delay unit includes a second switch, a first capacitor, and a first resistor. The first capacitor and the first resistor are connected in parallel between the two ends of the second switch. The control terminal of the second switch serves as the first sampling terminal. The first end of the second switch is connected to the control terminal of the first switch, and the second end of the second switch serves as the second sampling terminal.

3. The electronic switching circuit according to claim 2, characterized in that, The switching module includes: a third switching transistor, a second resistor, and a second capacitor. The first terminal of the third switching transistor serves as the signal output terminal, the second terminal of the third switching transistor serves as the first negative terminal, and the control terminal of the third switching transistor serves as the first control terminal. The second resistor and the second capacitor are connected in parallel between the control terminal and the second terminal of the third switching transistor.

4. The electronic switching circuit according to claim 2, characterized in that, The protection unit further includes a second overcurrent protection device and a fifth resistor. The second overcurrent protection device is connected between the power supply terminal and the auxiliary power supply port, and the fifth resistor is connected between the first terminal of the first switching transistor and the control terminal. The protection current of the second overcurrent protection device is greater than the protection current of the first overcurrent protection device.

5. The electronic switching circuit according to claim 3, characterized in that, The switching module further includes: a third diode, the anode of the third diode being connected to the control terminal of the third switching transistor, and the connection point of the second capacitor and the second resistor being connected to the cathode of the third diode; The delay unit further includes a fourth diode, which is connected between the first terminal of the second switching transistor and the first capacitor; the third and fourth diodes are used to prevent the capacitor from reverse discharging.

6. The electronic switching circuit according to claim 1, characterized in that, Also includes: A voltage regulator module is connected between the first interface and the second interface to stabilize the voltage between the first interface and the second interface at a preset value.

7. The electronic switching circuit according to claim 6, characterized in that, The voltage regulator module includes: at least one first diode and a second diode, wherein at least one first diode is connected in series between the first interface and the second interface; and the second diode is connected in series between the first interface and the second interface, with the connection direction opposite to that of the first diode.

8. A track circuit, characterized in that, Includes the electronic switch circuit, first rail, second rail, first power supply, rail relay and second power supply as described in any one of claims 1-7; The positive power supply terminal of the first rail is connected to the positive terminal of the first power supply, and the negative power supply terminal of the second rail is connected to the negative terminal of the first power supply; one end of the track relay is connected to the positive terminal of the second power supply, and the negative terminal of the second power supply is connected to the negative power supply terminal of the second rail. The first interface of the electronic switch circuit is connected to the positive power receiving end of the first rail; the second interface of the electronic switch circuit is connected to the negative power receiving end of the second rail; and the auxiliary power supply port of the electronic switch circuit is connected to the positive terminal of the first power supply.

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