A track circuit

Abstract

This invention provides a track circuit, comprising: a transmitting side and a receiving side; both the transmitting and receiving sides include: a transceiver transformer, a lightning protection transformer, a transmission cable, and a matching transformer; a transceiver device is connected to the rail sequentially through the transceiver transformer, the lightning protection transformer, the transmission cable, and the matching transformer; the transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device; a resonant circuit is added to the lines on the transmitting side and / or the receiving side to reduce the power of the transmitting device and enhance the signal strength only within the current section; therefore, by using the track circuit provided in this application, the power of the track circuit transmitting equipment can be reduced, the strength of the received signal can be improved, and interference with power frequency signals can be further reduced.

Description

Technical Field

[0001] This invention belongs to the field of railway signaling technology, and more specifically, relates to a track circuit. Background Technology

[0002] Track circuits are mainly used to check the usage status of tracks, such as occupancy and vacancy, and to monitor the integrity of rails. They are an important guarantee for improving the safety and reliability of train operation. In the current ZPW-2000A track circuit, the transmitting equipment outputs signals, and the receiving equipment analyzes the signals to determine the usage status of the rails. Therefore, in order to improve the signal recognition capability of the receiving equipment, it is necessary to increase the power of the transmitting equipment so that the signal has a higher strength when it reaches the receiving equipment.

[0003] However, this method increases the power of the track circuit transmitting equipment, which is detrimental to its service life. For the receiving equipment, in addition to receiving normal signals from the track circuit, it can also receive interference from other signals, which reduces the receiving equipment's ability to recognize signals. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a track circuit that reduces the power of the track circuit transmitting device, increases the strength of the received signal, and further reduces interference with power frequency signals.

[0005] This application discloses a track circuit, including: a transmitting side and a receiving side;

[0006] Both the transmitting and receiving sides include: transceiver transformers, lightning protection transformers, transmission cables, matching transformers, and tuning units;

[0007] The transceiver is connected to the rail in sequence via the transceiver transformer, the lightning protection transformer, the transmission cable, and the matching transformer; the tuning unit is located between the two connection points of the matching transformer and the rail.

[0008] The transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device;

[0009] A resonant circuit is added to the lines on the transmitting and / or receiving sides to reduce the power of the transmitting device and enhance the signal strength only within the local segment.

[0010] Optionally, in the above-described track circuit, the resonant circuit enhances the track circuit signal by at least one stage.

[0011] Optionally, in the above-described track circuit, the resonant circuit provides two-stage enhancement to the track circuit signal.

[0012] Optionally, in the above track circuit, the resonant circuit includes: a first capacitor;

[0013] The first capacitor is connected in parallel with the secondary winding of the matching transformer, and the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit.

[0014] Optionally, in the above-described track circuit, the number of turns of the secondary winding of the matching transformer can be changed so that the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit.

[0015] Optionally, in the above track circuit, the resonant circuit includes: a second capacitor; the secondary winding of the matching transformer adopts a tapped design;

[0016] Two terminals are drawn from the secondary winding of the matching transformer and connected to the rail for signal transmission. A second capacitor is installed between the secondary winding of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor and the secondary winding of the matching transformer change from series resonance to parallel resonance.

[0017] Optionally, in the above-described track circuit, one end of the second capacitor is connected to a tap of the secondary winding of the matching transformer;

[0018] The other end of the second capacitor is connected to the connection point between one end of the rail and one end of the resonant unit.

[0019] The other end of the resonant unit is connected to the other end of the rail and the other tap of the secondary winding of the matching transformer.

[0020] Optionally, in the above track circuit, the resonant circuit includes: a third capacitor;

[0021] The third capacitor is connected in series with the secondary winding of the transceiver transformer, and the third capacitor and the secondary winding of the transceiver transformer form a series resonant circuit.

[0022] Optionally, in the above track circuit, the resonant circuit includes: a first capacitor, a third capacitor, and a second capacitor;

[0023] The first capacitor is connected in parallel with the secondary winding of the matching transformer, and the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit.

[0024] Two terminals are drawn from the secondary winding of the matching transformer and connected to the rail for signal transmission. A second capacitor is set between the secondary winding of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor and the secondary winding of the matching transformer change from series resonance to parallel resonance.

[0025] The third capacitor is connected in series with the secondary winding of the transceiver transformer, and the third capacitor and the secondary winding of the transceiver transformer form a series resonant circuit.

[0026] Optionally, in the above track circuit, a resonant circuit is added to both the transmitting and receiving lines.

[0027] As can be seen from the above technical solution, the track circuit provided by the present invention includes: a transmitting side and a receiving side; both the transmitting side and the receiving side include: a transceiver transformer, a lightning protection transformer, a transmission cable, and a matching transformer; the transceiver device is connected to the rail in sequence through the transceiver transformer, the lightning protection transformer, the transmission cable, and the matching transformer; the transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device; a resonant circuit is added to the lines on the transmitting side and / or the receiving side to reduce the power of the transmitting device and enhance the signal strength only within the current section; therefore, by using the track circuit provided by this application, the power of the track circuit transmitting equipment can be reduced, the strength of the received signal can be improved, and interference with the power frequency signal can be further reduced. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of a track circuit provided in an embodiment of the present invention;

[0030] Figure 2 This is a schematic diagram of another track circuit provided in an embodiment of the present invention;

[0031] Figure 3 This is a schematic diagram of another track circuit provided in an embodiment of the present invention;

[0032] Figure 4 This is a schematic diagram of another track circuit provided in an embodiment of the present invention;

[0033] Figure 5 This is a schematic diagram of another track circuit provided in an embodiment of the present invention;

[0034] Figure 6 This is a schematic diagram of another track circuit provided in an embodiment of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] In this application, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0037] This application provides a track circuit to address the problem that increasing the power of the transmitting device in the prior art is detrimental to its service life; at the same time, for the receiving device, in addition to receiving the normal signal from the track circuit, it may also receive interference from other signals, which reduces the problem of signal recognition by the receiving device from another aspect.

[0038] See Figure 1 The track circuit includes a transmitting side and a receiving side.

[0039] See Figure 2 Both the transmitting and receiving sides include: transceiver transformers, lightning protection transformers, transmission cables, matching transformers, and resonant units.

[0040] The transceiver unit is connected to the rail in sequence via a transceiver transformer, a lightning protection transformer, a transmission cable, and a matching transformer.

[0041] The tuning unit is located between the two connection points of the matching transformer and the rail.

[0042] The transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device.

[0043] For ease of explanation, each transformer and transmission cable will be given a distinct name.

[0044] The transmitting side includes a transmitting transformer, a transmitting lightning protection transformer, a transmitting transmission cable, a transmitting matching transformer, and a transmitting tuning unit.

[0045] The transmitting device is connected to the rail sequentially via a transmitting transformer, a transmitting lightning protection transformer, a transmitting transmission cable, and a transmitting matching transformer. The transmitting tuning unit is located between the two connection points of the transmitting matching transformer and the rail.

[0046] Specifically, the transmitting device is connected to the primary winding I of the transmitting transformer; the secondary winding II of the transmitting transformer is connected to the primary winding I of the transmitting lightning protection transformer; the secondary winding II of the transmitting lightning protection transformer is connected to one end of the transmitting transmission cable, and the other end of the transmitting transmission cable is connected to the primary winding I of the transmitting matching transformer; one end of the secondary winding II of the transmitting matching transformer is connected to one end of the rail and one end of the transmitting tuning unit; the other end of the secondary winding II of the transmitting matching transformer is connected to the other end of the rail and the other end of the transmitting tuning unit.

[0047] The receiving side includes a receiving transformer, a receiving lightning protection transformer, a receiving transmission cable, and a receiving matching transformer.

[0048] The receiving device is connected to the rail in sequence through a receiving transformer, a receiving lightning protection transformer, a receiving transmission cable, and a receiving matching transformer.

[0049] Specifically, the receiving device is connected to the primary winding I of the receiving transformer; the secondary winding II of the receiving transformer is connected to the primary winding I of the receiving lightning protection transformer; the secondary winding II of the receiving lightning protection transformer is connected to one end of the receiving transmission cable, and the other end of the receiving transmission cable is connected to the primary winding I of the receiving matching transformer; one end of the secondary winding II of the receiving matching transformer is connected to one end of the rail and one end of the transmitting tuning unit; the other end of the secondary winding II of the transmitting matching transformer is connected to the other end of the rail and the other end of the transmitting tuning unit.

[0050] This track circuit is applicable to the ZPW-2000 track circuit system. Of course, it may also be applicable to other systems, which will not be elaborated here. It depends on the actual situation and all are within the protection scope of this application.

[0051] The following explanation uses the ZPW-2000A track circuit as an example:

[0052] like Figure 5As shown, the basic structure of the ZPW-2000 track circuit includes: a transmitting unit, lightning protection transformer, transmission cable, and matching transformer on the transmitting side; and a matching transformer, transmission cable, lightning protection transformer, and receiving unit on the receiving side, connected by a steel rail. The matching transformers on both the transmitting and receiving sides are outdoor equipment, while the lightning protection transformers, transmitting units, and receiving units on both sides are indoor equipment. The track circuit signal frequencies are f1 = 1700Hz; f2 = 2000Hz; f3 = 2300Hz; f4 = 2600Hz, with each segment corresponding to a specific signal frequency.

[0053] It should be noted that the parameters of the same devices on the transmitting and receiving sides are consistent.

[0054] Add a resonant circuit to the lines on the transmitting and / or receiving sides to reduce the power of the transmitting device and enhance the signal strength only within the local segment.

[0055] In other words, a resonant circuit can be added only to the line on the transmitting side to reduce the power of the transmitting device and enhance the signal strength only within this section, that is, only enhance the transmitted signal strength within this section.

[0056] Alternatively, a resonant circuit can be added to the line on the receiving side to reduce the power of the transmitting device and enhance the signal strength only within this section, that is, only enhance the received signal strength within this section.

[0057] Alternatively, resonant circuits can be added to both the receiving and transmitting lines to reduce the power of the transmitting device and enhance the signal strength only within the current segment. In other words, only the strength of the received and transmitted signals within the current segment is enhanced.

[0058] In other words, the signal frequencies of this segment and those outside this segment are different; for this segment, this resonant circuit can resonate with the frequency signal of this segment, increasing the signal strength, but it cannot resonate with other frequency signals outside this segment, so the signal strength is low.

[0059] Therefore, this resonant circuit only enhances the signal strength within its own segment, resulting in the receiving unit receiving the strongest signal while being less susceptible to interference signals from outside the segment.

[0060] In this embodiment, both the transmitting and receiving sides include: a transceiver transformer, a lightning protection transformer, a transmission cable, and a matching transformer; the transceiver device is connected to the rail in sequence through the transceiver transformer, the lightning protection transformer, the transmission cable, and the matching transformer; the transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device; a resonant circuit is added to the lines on the transmitting and / or receiving sides to reduce the power of the transmitting device and enhance the signal strength only within this section; therefore, by using the track circuit provided in this application, the power of the track circuit transmitting equipment can be reduced, the strength of the received signal can be improved, and interference with the power frequency signal can be further reduced.

[0061] In practical applications, resonant circuits enhance track circuit signals by at least one stage.

[0062] In other words, the resonant circuit enhances the track circuit signal by at least one level, and other levels of enhancement are also possible. These will not be elaborated here, but will be determined according to the actual situation, and are all within the scope of protection of this application.

[0063] Specifically, the resonant circuit enhances the track circuit signal in two stages; of course, other stages of enhancement are also possible, which will not be elaborated here, depending on the actual situation, and all are within the scope of protection of this application.

[0064] In other words, if a resonant circuit is installed only on the transmitting side of the line, the resonant circuit will enhance the transmitted signal on the transmitting side line by N levels; that is, the track circuit will enhance the signal by N levels. N is the number of enhancement levels.

[0065] If a resonant circuit is installed only on the receiving side line, then the resonant circuit will enhance the received signal on the receiving side line by N levels; that is, the track circuit will enhance the signal by N levels. N is the number of enhancement levels.

[0066] If resonant circuits are installed on both the transmitting and receiving sides of the line, the resonant circuit on the transmitting side will enhance the transmitted signal on the transmitting side line by N levels; the resonant circuit on the receiving side will enhance the received signal on the receiving side line by M levels; that is, the track circuit will enhance by (M+N) levels; where M and N are the enhancement levels.

[0067] In practical applications, resonant circuits are added to both the transmitting and receiving lines.

[0068] In other words, the resonant circuit on the transmitting side enhances the transmitted signal on the transmitting side line by one stage; the resonant circuit on the receiving side enhances the received signal on the receiving side line by one stage; that is, the track circuit enhances the signal by at least two stages.

[0069] The specific enhancement levels on the transmitting and receiving sides will not be elaborated here, but can be determined according to the actual situation, and are all within the protection scope of this application.

[0070] In practical applications, this resonant circuit can have various resonance modes. Two of them are described below:

[0071] (1) In practical applications, see Figure 3 The resonant circuit includes: a first capacitor C1.

[0072] The first capacitor C1 is connected in parallel with the secondary winding II of the matching transformer, and the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0073] Specifically, one end of the first capacitor C1 is connected to one end of the secondary winding II of the matching transformer; the other end of the first capacitor C1 is connected to the other end of the secondary winding II of the matching transformer.

[0074] Therefore, the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0075] The parallel resonant circuit can enhance the signal. The specific enhancement process will not be described in detail here, but will be determined according to the actual situation, and all of them are within the protection scope of this application.

[0076] In practical applications, the number of turns of the secondary winding II of the matching transformer is changed so that the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0077] Specifically, the number of turns of the secondary winding II of the matching transformer is related to the capacitance value of the first capacitor C1. This will not be elaborated here, but can be determined according to the actual situation, and all are within the protection scope of this application.

[0078] Furthermore, changing the number of turns in the secondary winding II of the matching transformer is not achieved by using a different transformer. The purpose of changing the number of turns is mainly to adjust the inductance value of the secondary winding II of the matching transformer, so that the secondary winding II of the matching transformer and the first capacitor C1 form a parallel resonance. The specific number of turns depends on the first capacitor C1, which will not be elaborated here, and is all within the scope of protection of this application.

[0079] In practical applications, the resonant circuit includes: a second capacitor C2; and the secondary winding II of the matching transformer adopts a tapped design.

[0080] Two terminals are drawn from the secondary winding II of the matching transformer and connected to the rail for signal transmission. A second capacitor C2 is connected between the secondary winding II of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance.

[0081] Specifically, the two ends of the secondary winding II of the matching transformer are connected to the first capacitor C1; one tap of the secondary winding II of the matching transformer is connected to one end of the second capacitor C2; the other tap of the secondary winding II of the matching transformer is connected to one end of the rail, and the other end of the second capacitor C2 is connected to the other end of the rail.

[0082] Therefore, when the train is not shunt at the corresponding tuning unit, that is, when the train is not shunt at the corresponding tuning unit, the second capacitor C2 and the secondary winding II of the matching transformer form a series resonant circuit.

[0083] When the train is shunt at the corresponding tuning unit, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance; that is, the second capacitor C2 and the secondary winding II of the matching transformer change from a series resonant circuit to a parallel resonant circuit.

[0084] In practical applications, one end of the second capacitor C2 is connected to a tap of the secondary winding II of the matching transformer; the other end of the second capacitor C2 is connected to the connection point between one end of the rail and one end of the resonant unit; the other end of the resonant unit is connected to the other end of the rail and another tap of the secondary winding II of the matching transformer.

[0085] In other words, by increasing the number of turns in the secondary winding II of the outdoor matching transformer, the secondary winding II of the entire matching transformer and the first capacitor C1 form a parallel resonance with a resonant frequency of 50Hz for the power frequency signal. Since the parallel resonance generates a large impedance, the signal value of the power frequency signal in the track circuit path is reduced, minimizing interference.

[0086] The track circuit path refers to the section from the transmitting device to the receiving device. For electrified track circuits, in addition to the track circuit signal, there is also a 50Hz power frequency traction current signal in the rails. Under certain conditions, the power frequency signal can interfere with the track circuit path by entering through the tuning unit.

[0087] A tap design is implemented in the secondary winding II of the matching transformer, from which two terminals are tapped to connect to the rail for signal transmission. A second capacitor C2 is connected in series, so that the inductance between the second capacitor C2 and the tap terminals forms a series resonance. The resonant frequency is the signal frequency of this section. This design can enhance the track circuit signal of this section and suppress non-signals.

[0088] In this embodiment, the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonance, which can suppress the power frequency signal from entering the track circuit system and reduce the interference of the power frequency signal. At the same time, when the train is shunt at the resonant unit, that is, when a short circuit is formed, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance, and the impedance increases from low to high. This will not cause large fluctuations in the signal current in the channel, and at the same time improve the shunt sensitivity.

[0089] (2) In practical applications, see Figure 4 The resonant circuit includes: a third capacitor C3.

[0090] The third capacitor C3 is connected in series with the secondary winding II of the transceiver transformer, and the third capacitor C3 and the secondary winding II of the transceiver transformer form a series resonant circuit.

[0091] Specifically, one end of the secondary winding II of the transceiver transformer is connected to one end of the primary winding I of the lightning protection transformer through the third capacitor C3; the other end of the secondary winding II of the transceiver transformer is connected to the other end of the primary winding I of the lightning protection transformer.

[0092] In other words, a transceiver transformer and a third capacitor C3 are added indoors. The transformer has a turns ratio of 1. The third capacitor C3 and the inductance of the secondary winding II of the transceiver transformer form a series resonance. The resonant frequency is the signal frequency of the track circuit in this section. This method can maximize the current in the resonant tank circuit, so the voltage across the secondary winding II of the transceiver transformer will also reach its maximum. As a result, the receiving equipment receives the strongest signal, while the interference signals from outside this section are weaker.

[0093] It should be noted that the signal frequencies in this section are different from those in other sections. For this section, this circuit design can create resonance for the frequency signal in this section, increasing the signal strength, but it cannot create resonance for other frequency signals outside this section, resulting in lower signal strength.

[0094] This application utilizes the principle of series resonance and, through circuit design, enhances the track circuit signal while suppressing interference signals, thus significantly increasing the signal strength reaching the receiving equipment. Based on this, transmitter power can be reduced, and transmitter lifespan can be increased.

[0095] It should be noted that, see Figure 5 The structure of the resonant circuit can be at least one of (1) and (2) above. It will not be described in detail here. It can be determined according to the actual situation. All of them are within the protection scope of this application.

[0096] The structure of the resonant circuit can be described below using a combination of the above (1) and (2).

[0097] In practical applications, the resonant circuit includes: a first capacitor C1, a third capacitor C3, and a second capacitor C2.

[0098] The first capacitor C1 is connected in parallel with the secondary winding II of the matching transformer, and the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0099] One end of the first capacitor C1 is connected to one end of the secondary winding II of the matching transformer; the other end of the first capacitor C1 is connected to the other end of the secondary winding II of the matching transformer.

[0100] Therefore, the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0101] The parallel resonant circuit can enhance the signal. The specific enhancement process will not be described in detail here, but will be determined according to the actual situation, and all of them are within the protection scope of this application.

[0102] In practical applications, the number of turns of the secondary winding II of the matching transformer is changed so that the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonant circuit.

[0103] Specifically, the number of turns of the secondary winding II of the matching transformer is related to the capacitance value of the first capacitor C1. This will not be elaborated here, but can be determined according to the actual situation, and all are within the protection scope of this application.

[0104] Furthermore, changing the number of turns in the secondary winding II of the matching transformer is not achieved by using a different transformer. The purpose of changing the number of turns is mainly to adjust the inductance value of the secondary winding II of the matching transformer, so that the secondary winding II of the matching transformer and the first capacitor C1 form a parallel resonance. The specific number of turns depends on the first capacitor C1, which will not be elaborated here, and is all within the scope of protection of this application.

[0105] Two terminals are drawn from the secondary winding II of the matching transformer and connected to the rail for signal transmission. A second capacitor C2 is connected between the secondary winding II of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance.

[0106] When there is a train on the rail, it is considered a branching state.

[0107] Specifically, the two ends of the secondary winding II of the matching transformer are connected to the first capacitor C1; one tap of the secondary winding II of the matching transformer is connected to one end of the second capacitor C2; the other tap of the secondary winding II of the matching transformer is connected to one end of the rail, and the other end of the second capacitor C2 is connected to the other end of the rail.

[0108] Therefore, when the train is not shunt at the corresponding tuning unit, that is, when the train is not shunt at the corresponding tuning unit, the second capacitor C2 and the secondary winding II of the matching transformer form a series resonant circuit.

[0109] When the train is shunt at the corresponding tuning unit, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance; that is, the second capacitor C2 and the secondary winding II of the matching transformer change from a series resonant circuit to a parallel resonant circuit.

[0110] In practical applications, one end of the second capacitor C2 is connected to a tap of the secondary winding II of the matching transformer; the other end of the second capacitor C2 is connected to the connection point between one end of the rail and one end of the resonant unit; the other end of the resonant unit is connected to the other end of the rail and another tap of the secondary winding II of the matching transformer.

[0111] In other words, by increasing the number of turns in the secondary winding II of the outdoor matching transformer, the secondary winding II of the entire matching transformer and the first capacitor C1 form a parallel resonance with a resonant frequency of 50Hz for the power frequency signal. Since the parallel resonance generates a large impedance, the signal value of the power frequency signal in the track circuit path is reduced, minimizing interference.

[0112] The track circuit path refers to the section from the transmitting device to the receiving device. For electrified track circuits, in addition to the track circuit signal, there is also a 50Hz power frequency traction current signal in the rails. Under certain conditions, the power frequency signal can interfere with the track circuit path by entering through the tuning unit.

[0113] A tap design is implemented in the secondary winding II of the matching transformer, from which two terminals are tapped to connect to the rail for signal transmission. A second capacitor C2 is connected in series, so that the inductance between the second capacitor C2 and the tap terminals forms a series resonance. The resonant frequency is the signal frequency of this section. This design can enhance the track circuit signal of this section, while suppressing signals from other sections.

[0114] In this embodiment, the first capacitor C1 and the secondary winding II of the matching transformer form a parallel resonance, which can suppress the power frequency signal from entering the track circuit system and reduce the interference of the power frequency signal. At the same time, when the train is shunt at the resonant unit, that is, when a short circuit is formed, the second capacitor C2 and the secondary winding II of the matching transformer change from series resonance to parallel resonance, and the impedance increases from low to high. This will not cause large fluctuations in the signal current in the channel, and at the same time improve the shunt sensitivity.

[0115] The third capacitor C3 is connected in series with the secondary winding II of the transceiver transformer, and the third capacitor C3 and the inductance of the secondary winding II of the transceiver transformer form a series resonant circuit.

[0116] Specifically, one end of the secondary winding II of the transceiver transformer is connected to one end of the primary winding I of the lightning protection transformer through the third capacitor C3; the other end of the secondary winding II of the transceiver transformer is connected to the other end of the primary winding I of the lightning protection transformer.

[0117] In other words, a transceiver transformer and a third capacitor C3 are added indoors. The transformer has a turns ratio of 1. The third capacitor C3 and the inductance of the secondary winding II of the transceiver transformer form a series resonance. The resonant frequency is the signal frequency of the track circuit in this section. This method can maximize the current in the resonant tank circuit, so the voltage across the secondary winding II of the transceiver transformer will also reach its maximum. As a result, the receiving equipment receives the strongest signal, while the interference signals from outside this section are weaker.

[0118] It should be noted that the signal frequencies in this section are different from those in other sections. For this section, this circuit design can create resonance for the frequency signal in this section, increasing the signal strength, but it cannot create resonance for other frequency signals outside this section, resulting in lower signal strength.

[0119] This application utilizes the principle of series resonance and, through circuit design, enhances the track circuit signal while suppressing interference signals, thus significantly increasing the signal strength reaching the receiving equipment. Based on this, transmitter power can be reduced, and transmitter lifespan can be increased.

[0120] like Figure 6 As shown below, the specific working process of the track circuit is explained:

[0121] ①: This indicates the axle state of the train when it is on the track (branched state). The impedance of this axle is generally set to purely resistive, with a resistance value of R≈0.

[0122] ②: When the resistance value of the wheel axle is R≈0, since the wheel axle is close to BA1, the resistance at BA1 is also approximately equal to 0.

[0123] It should be noted that both BA1 and BA2 are tuning units.

[0124] ③: When the impedance at point ② is approximately zero, then the impedance at this point is also zero.

[0125] ④: When the impedance at point ③ is zero, C2 is connected in parallel with the coil at point II of the matching transformer. By designing C2 and the coil to be in parallel resonance with the coil inductance, a high impedance can be achieved.

[0126] ⑤: When the impedance at point ④ is high, the load of the transmitting unit also becomes high-impedance. Since the transmitting unit is approximately a constant voltage source, meaning the output voltage remains constant, the higher the load impedance, the lower the current. This makes the entire track circuit safer.

[0127] In this embodiment, the series resonance principle is utilized, and through circuit design, interference signals are suppressed while the track circuit signal is enhanced in two stages. This significantly increases the signal strength reaching the receiving device, thereby reducing transmitter power and extending transmitter lifespan. The parallel resonance of outdoor C1 and the matching transformer coil suppresses power frequency signals from entering the track circuit system, reducing power frequency interference. Simultaneously, when the train shunts at BA, i.e., a short circuit is formed, C2 and the secondary coil of the matching transformer change from series resonance to parallel resonance, and the impedance increases from low to high. This prevents large fluctuations in the signal current within the channel and improves shunt sensitivity.

[0128] The features described in the various embodiments of this specification can be substituted for or combined with each other. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, for system or system embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the description of the method embodiments. The systems and system embodiments described above are merely illustrative. Units described as separate components may or may not be physically separate. Components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without creative effort.

[0129] Those skilled in the art will further recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of both. To clearly illustrate the interchangeability of hardware and software, the components and steps of the various examples have been generally described in terms of functionality in the foregoing description. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementations should not be considered beyond the scope of this invention.

[0130] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A track circuit, characterized in that, include: Sending side and receiving side; Both the transmitting side and the receiving side include: a transceiver transformer, a lightning protection transformer, a transmission cable, a matching transformer, and a tuning unit; The transceiver is connected to the rail in sequence via the transceiver transformer, the lightning protection transformer, the transmission cable, and the matching transformer; the tuning unit is located between the two connection points of the matching transformer and the rail. The transceiver device on the transmitting side is a transmitting device, and the transceiver device on the receiving side is a receiving device; A resonant circuit is added to the lines on the transmitting side and / or receiving side to reduce the power of the transmitting device and enhance the signal strength only within the local segment; the resonant circuit includes: a first capacitor and a second capacitor; The first capacitor is connected in parallel with the secondary winding of the matching transformer, and the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit. The secondary winding of the matching transformer adopts a tap design. Two terminals are drawn from the secondary winding of the matching transformer and connected to the rail for signal transmission. A second capacitor is installed between the secondary winding of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor and the secondary winding of the matching transformer change from series resonance to parallel resonance.

2. The track circuit according to claim 1, characterized in that, The resonant circuit enhances the track circuit signal by at least one stage.

3. The track circuit according to claim 2, characterized in that, The resonant circuit provides two-stage amplification of the track circuit signal.

4. The track circuit according to claim 1, characterized in that, The number of turns in the secondary winding of the matching transformer is changed so that the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit.

5. The track circuit according to claim 1, characterized in that, One end of the second capacitor is connected to a tap of the secondary winding of the matching transformer; The other end of the second capacitor is connected to the connection point between one end of the rail and one end of the tuning unit. The other end of the tuning unit is connected to the other end of the rail and the other tap of the secondary winding of the matching transformer.

6. The track circuit according to claim 1, characterized in that, The resonant circuit includes: a third capacitor; The third capacitor is connected in series with the secondary winding of the transceiver transformer, and the third capacitor and the secondary winding of the transceiver transformer form a series resonant circuit.

7. The track circuit according to claim 1, characterized in that, The resonant circuit includes: a first capacitor, a third capacitor, and a second capacitor; The first capacitor is connected in parallel with the secondary winding of the matching transformer, and the first capacitor and the secondary winding of the matching transformer form a parallel resonant circuit. Two terminals are drawn from the secondary winding of the matching transformer and connected to the rail for signal transmission. A second capacitor is set between the secondary winding of the matching transformer and the rail so that when the train is shunt at the tuning unit on the corresponding side, the second capacitor and the secondary winding of the matching transformer change from series resonance to parallel resonance. The third capacitor is connected in series with the secondary winding of the transceiver transformer, and the third capacitor and the secondary winding of the transceiver transformer form a series resonant circuit.

8. The track circuit according to claim 1, characterized in that, Resonant circuits are added to both the transmitting and receiving lines.

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