Track loop device

Abstract

In a track circuit device that determines the location of a train based on an AC signal transmitted from a transmission point to the rails, the objective is to enable determination of which of the two sections on either side of the transmission point is the section where the train is located, thereby improving the accuracy of train location determination. [Solution] The track circuit device 1 transmits an AC signal from a transmission point, which is the boundary of a section of rail, to the rails. For sections on both sides of the transmission point, it determines whether or not a section is occupied by a train based on the components of adjacent AC signals transmitted from adjacent transmission points, which are the other boundaries of each section on both sides, included in the received signal at the transmission point. It calculates an impedance equivalent value based on the AC signal transmitted from the transmission point, and determines the location of the train within the section occupied by the train, with the transmission point as the reference point, based on the impedance equivalent value.

Description

Technical Field

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[0001] The present invention relates to a track circuit device.

Background Art

[0002] Conventional track circuit devices connect a transmitter that transmits a train detection signal to one end of the rails of the track circuit, and determine the presence of a train based on a decrease in the reception level at a receiver connected to the other end. Therefore, a transmission power of a certain level or higher was required. A technique for an energy-saving track circuit device that eliminates the need for a receiver based on a principle completely different from this conventional one is disclosed in Patent Document 1.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, it has been found that there is room for further improvement in the technology of the track circuit device disclosed in Patent Document 1. The first improvement point is that in the case of a jointless track circuit, since the transmission signal propagates to the rails on both sides of the transmission point, it is difficult to distinguish which is the occupied section. The second improvement point is that since the impedance of the track circuit changes due to a change in leakage conductance, the determination accuracy of the occupied position decreases.

[0005] The problem to be solved by the present invention is to enable determination of which of the sections on both sides of the transmission point is the occupied section in a track circuit device that determines the occupied position of a train based on an AC signal transmitted from the transmission point to the rails. A further problem is to improve the determination accuracy of the occupied position.

Means for Solving the Problems

[0006] Note: In the translation of the patent number in , "XXXXXX" is used as a placeholder because the original number is not fully provided. You can replace it with the complete patent number. The first invention for solving the above problem is: A transmitting means that transmits an AC signal from a transmission point which is the boundary of a section of rail to the rail (for example, the transceiver 10 and transmission control unit 31 in Figure 13), A means for determining whether the sections on both sides of the aforementioned transmission point are occupied sections (for example, the occupied section determination unit 42 in Figure 13), A calculation means (for example, the impedance equivalent value calculation unit 41 in Figure 13) that calculates an impedance equivalent value based on the AC signal transmitted from the aforementioned transmission point, A position determination means (for example, the position determination unit 43 in Figure 13) that determines the position of the train within the track section relative to the transmission point based on the impedance equivalent value, This is a track circuit device equipped with [a specific feature / feature].

[0007] According to the first invention, in a track circuit device that determines the location of a train based on an AC signal transmitted from a transmission point to the rails, it is determined whether the section on both sides of the transmission point is a tracked section or not, and then the location of the train within the tracked section relative to the transmission point is determined based on the impedance equivalent value based on the AC signal transmitted from the transmission point. This makes it possible to improve the accuracy of determining the location of the train.

[0008] The second invention is, in the above invention, Receiving means for receiving the signal at the aforementioned transmission point (for example, the transceiver 10 in Figure 13), Furthermore, The occupancy section determination means performs the occupancy section determination based on the component of the adjacent AC signal transmitted from the adjacent transmission point, which is the other boundary of each of the two sections, included in the received signal received by the receiving means. It is a track circuit device.

[0009] According to the second invention, it becomes possible to distinguish and determine which of the two sections on either side of the transmission point is the occupied section from the received signal at the transmission point. If both sections on either side of the transmission point are unoccupied sections, the transmission point receives the adjacent AC signal transmitted from the adjacent transmission point, which is the other boundary of the two sections. When a train enters one of the two sections from this state, the left and right rails of that section are short-circuited by the train's axle, and the adjacent AC signal transmitted from the adjacent transmission point, which is the other boundary of that section, is no longer received. For example, by making the frequencies of the adjacent AC signals different, it is possible to distinguish which adjacent transmission point's transmitted adjacent AC signal is being received from the frequency components included in the received signal at the transmission point. This makes it possible to distinguish and determine which of the two sections on either side of the transmission point is the occupied section.

[0010] The third invention is, in the above invention, A train passage determination means (for example, the train passage determination unit 44 in Figure 13) that determines whether the impedance equivalent value satisfies predetermined minimum conditions and determines whether a train has passed the transmission point, A passing output means (for example, the passing output unit 45 in Figure 13) outputs a train passing signal indicating that a train has passed when the train passing determination means determines that a train has passed, Furthermore, The occupancy section determination means performs the occupancy section determination based on the train passing signal relating to the adjacent transmission point which is the other boundary of each of the two sections. It is a track circuit device.

[0011] According to the third invention, it becomes possible to distinguish and determine which of the two sections on either side of the transmission point is the section where a train is present, based on the train passing signal from an adjacent transmission point which is the other boundary of each section on either side of the transmission point. The impedance equivalent value based on the transmission signal changes according to the train's position on the track, that is, the short-circuit position between the left and right rails caused by the train's axle. The impedance equivalent value decreases as the distance between the transmission point and the short-circuit position decreases, and is at its minimum when a train passes a transmission point where the transmission point is the short-circuit position of the rails. A train passing a transmission point corresponds to a train entering one section from the other of the two sections on either side of the transmission point. Therefore, it becomes possible to distinguish and determine which of the two sections on either side of the transmission point is the section where a train is present, based on the train passing signal from an adjacent transmission point.

[0012] The fourth invention is, in the above invention, Based on the impedance equivalent value in a state where the occupancy section determination means determines that the occupancy section is not an occupancy section, a correspondence relationship setting means (for example, the correspondence relationship setting unit 46 in Figure 13) sets the correspondence relationship between the impedance equivalent value and the occupancy location. Furthermore, The position determination means determines the location by referring to the correspondence relationship. It is a track circuit device.

[0013] According to the fourth invention, it is possible to improve the accuracy of determining the location of a train. The impedance equivalent value changes in accordance with the change in leakage conductance generated in the rail. For this reason, for example, the correspondence between the impedance equivalent value and the location of a train can be determined for each assumed amount of leakage conductance, and an appropriate correspondence can be selected and set from the impedance equivalent value when it is determined that the section is not a train location. This makes it possible to improve the accuracy of determining the location of a train.

[0014] The fifth invention is, in the above invention, Receiving means for receiving the signal at the aforementioned transmission point (for example, the transceiver 10 in Figure 13), Furthermore, The aforementioned transmission means is Performing intermittent transmission of the AC signal; Based on a given noise band included in the received signal received by the receiving means during a period when the AC signal is not being transmitted, changing the frequency of the AC signal to be transmitted to a frequency that avoids the noise band; Doing; It is a track circuit device.

[0015] According to the fifth invention, the transmission frequency of the AC signal transmitted from the transmission point can be set to a frequency that avoids a noise band such as the frequency of the return noise of the rail, so it is not affected by other signals flowing through the rail. Also, by setting the frequency to avoid the noise band, the transmission level of the AC signal can be reduced, and it becomes possible to achieve energy saving of the track circuit device in combination with intermittent transmission.

[0016] The sixth invention is in the above-mentioned invention, The transmission means switches the frequency of the AC signal to be transmitted based on the occupancy position determined by the position determination means. It is a track circuit device.

[0017] According to the sixth invention, since the impedance change amount of the track circuit varies depending on the frequency of the AC signal and the occupancy position, by switching the frequency of the AC signal to be transmitted according to the occupancy position, it is possible to improve the calculation accuracy of the impedance equivalent value and the determination accuracy of the occupancy position. For example, when it is determined that the detection section is an unoccupied section, an AC signal with a low frequency is used, and after it is determined that the detection section is an occupied section, if the distance from the transmission point to the occupancy position is within a predetermined distance, it can be switched to an AC signal with a high frequency.

[0018] The seventh invention is, Transmission means (for example, the transceiver 10 and the transmission control unit 31 in FIG. 13) that transmits an AC signal from a transmission point, which is the boundary of a section partitioning the rail, to the rail; A means for determining whether the section related to the transmission point is a occupancy section (for example, the occupancy section determination unit 42 in Figure 13), A calculation means (for example, the impedance equivalent value calculation unit 41 in Figure 13) that calculates an impedance equivalent value based on the AC signal transmitted from the aforementioned transmission point, Based on the impedance equivalent value in a state where the occupancy section determination means determines that the occupancy section is not an occupancy section, a correspondence relationship setting means (for example, the correspondence relationship setting unit 46 in Figure 13) sets the correspondence relationship between the impedance equivalent value and the occupancy location, When the aforementioned train location determination means determines that a train is in a train location section, a position determination means (for example, the position determination unit 43 in Figure 13) determines the location of the train within the train location section relative to the transmission point, based on the impedance equivalent value and the correspondence relationship, This is a track circuit device equipped with [a specific feature / feature].

[0019] According to the seventh invention, in a track circuit device that determines the location of a train based on an AC signal transmitted from a transmission point to the rails, it is possible to improve the accuracy of determining the location of the train. After determining whether the detection section related to the transmission point is a train location section, the location of the train within the train location section relative to the transmission point is determined based on the impedance equivalent value based on the AC signal transmitted from the transmission point. The impedance equivalent value changes according to the change in leakage conductance generated in the rails. For this reason, for example, the correspondence between the impedance equivalent value and the location of the train is determined for each assumed amount of leakage conductance, and an appropriate correspondence is selected and set from the impedance equivalent value from the state in which the detection section is determined to be a train location section, compared to the state in which it is determined to be a train location section. This makes it possible to improve the accuracy of determining the location of the train in the train location section. [Brief explanation of the drawing]

[0020] [Figure 1] Examples of track circuit device applications. [Figure 2] An example of an equivalent circuit for an orbital circuit. [Figure 3]An example of an equivalent circuit for an orbital circuit. [Figure 4] An example of an equivalent circuit for an orbital circuit. [Figure 5] An example of the transmission voltage waveform and transmission current waveform of an AC signal. [Figure 6] An example of the correspondence between the location of the track and its equivalent impedance. [Figure 7] Diagram explaining how to determine the location of a railway line. [Figure 8] Diagram explaining how to determine the location of a railway line. [Figure 9] Diagram explaining how to determine the location of a railway line. [Figure 10] Diagram explaining how to determine the location of a railway line. [Figure 11] Diagram explaining how to determine the location of a railway line. [Figure 12] A diagram illustrating the setting of the correspondence between the location of the wire, the equivalent impedance value, and other related information. [Figure 13] An example of a track circuit system configuration. [Figure 14] Example of a transceiver configuration. [Figure 15] An example of a frequency information table. [Modes for carrying out the invention]

[0021] Preferred embodiments of the present invention will be described below with reference to the drawings. Note that the applicable forms of the present invention are not limited to the following embodiments. Also, in the drawings, the same elements are denoted by the same reference numerals. Furthermore, unless otherwise specified, "rail" refers to a pair of left and right rails, and does not refer to either the left or right rail.

[0022] Figure 1 shows an example of the application of the track circuit device 1 in this embodiment. The track circuit device 1 is installed in conjunction with each boundary of a section that divides the rails. The track circuit device 1 may be installed at the end of a section, or it may be installed in the center when both sections are combined to form a single distance range. Also, the track circuit in Figure 1 is an uninsulated track circuit.

[0023] Track circuit device 1 transmits AC signals from a corresponding boundary transmission point to the rails (more precisely, a pair of left and right rails), and determines the train's position based on the transmitted signals (AC signals). Track circuit device 1 designates the sections on both sides of a corresponding transmission point (two sections with the transmission point as the end) as detection sections and determines the train's position within these detection sections. The transmission level and frequency transmitted by track circuit device 1 from the transmission point are designed to detect the train's position within the detection sections. In the example in Figure 1, track circuit devices 1A to 1C are provided, corresponding to each of the three transmission points P1 to P3. For example, in track circuit device 1B, the second and third sections on both sides of transmission point P2 are the detection sections.

[0024] Furthermore, the frequency of the AC signal transmitted by the track circuit device 1 (transmission frequency) is set to a frequency that does not affect adjacent sections and is determined to differ between adjacent transmission points. As a result, as will be described in detail later, the track circuit device 1 can determine which of the detection sections is the section where a train is present. Then, the track circuit device 1 determines the location of the train in the section where a train is present based on the impedance equivalent value based on the transmitted signal.

[0025] The impedance equivalent value will now be explained. Figures 2 to 4 show the equivalent circuit when one detection section is considered as a track circuit. Figure 2 shows the equivalent circuit when no train is present, Figure 3 shows the equivalent circuit immediately after the train enters the detection section, and Figure 4 shows the equivalent circuit when the train reaches the transmission point. It is assumed that the rail condition is normal (no abnormalities have occurred). The combined impedance of these equivalent circuits is the impedance of the detection section as seen from the transmission point.

[0026] As shown in Figure 2, the equivalent circuit of the track circuit when no train is present consists of the rail inductance component La, the series resistance component Ra, the capacitance component C between the rails, and the leakage conductance component G = 1 / Rb. Furthermore, as shown in Figure 3, the equivalent circuit immediately after a train enters the detection section consists of the rail inductance component La, the series resistance component Ra, the capacitance component C between the left and right rails, the leakage conductance component G = 1 / Rb, and the impedance Rv due to the axle short circuit (short circuit at the train's axles on the left and right rails).

[0027] In this embodiment, since the track circuit is an unisolated track circuit, the AC signal transmitted from the transmission point to the rails propagates to the section adjacent to the detection section. Therefore, even if the train has not yet reached the detection section, if it is approaching within a certain distance, the axle short-circuit impedance Rv will have an effect. Furthermore, even after the train has moved out of the detection section, the axle short-circuit impedance Rv will have an effect until it moves away to a certain distance. The range in which this axle short-circuit impedance Rv has an effect (the range to which the AC signal reaches) is the detectable range. In addition, the impedance value of the detectable range is determined by each circuit element (rail inductance component La, series resistance component Ra, capacitance component C between the left and right rails, and leakage conductance component G = 1 / Rb), and therefore increases with distance from the AC signal transmission point to the axle short-circuit position (train's location). That is, the impedance value of the detectable range is largest when the train is not present and gradually decreases as the train approaches the AC signal transmission point.

[0028] Therefore, as shown in Figure 4, the equivalent circuit when the train reaches the transmission point consists only of the axle short-circuit impedance Rv, because the distance from the transmission point to the axle short-circuit position is very short, the rail inductance component La, the series resistance component Ra, and the capacitance component C between the left and right rails become very small, and the leakage conductance component G = 1 / Rb becomes very large. In this way, the equivalent circuit of the track circuit changes as the train moves through the detection section. In other words, the impedance of the track circuit changes.

[0029] Figure 5 shows an overview of the transmission voltage and transmission current waveforms of the AC signal transmitted to the rails. In Figure 5, the horizontal axis represents time and the vertical axis represents level, showing the transmission voltage and transmission current waveforms. Furthermore, assuming that the transmission voltage waveform is constant, the transmission current waveforms are shown when the train is not present (dashed line) and when the train reaches the transmission point (dotted line).

[0030] As shown in Figures 2 to 4, the equivalent circuit of the track circuit changes as the train moves from entering to exiting the detection section. In other words, the impedance of the detection section as seen from the AC signal transmission point changes, causing the transmitted current waveform to change relative to the transmitted voltage waveform. Specifically, as the train enters the detection section and approaches the transmission point, the phase of the transmitted current waveform shifts in the opposite direction relative to the transmitted voltage waveform, and the level (amplitude) of the transmitted current waveform increases. The amplitude (level) and phase of the transmitted current waveform change in accordance with the change in the impedance of the detection section. From this, the amplitude of the transmitted voltage waveform and the transmitted current waveform, and the phase difference of the transmitted current waveform relative to the transmitted voltage waveform can be considered as values ​​corresponding to the impedance of the track circuit (impedance equivalent values).

[0031] Figure 6 illustrates the correspondence between the train's location on the track and its impedance equivalent value. In Figure 6, the horizontal direction represents the position along the track. The lower part shows the detection sections of the track circuit device 1B, namely the first and second sections, and their detectable range. The upper part shows the correspondence between the train's location on the track and its impedance equivalent value as seen from the transmission point P2 of the track circuit device 1B.

[0032] As shown in Figures 2 to 4, the impedance equivalent value as seen from the transmission point P2 changes analogously as the train's position changes. For example, if train 3 approaches from the far side of the third section and moves away after passing the transmission point P2, the following occurs: When train 3 is far away and outside the detectable range, the impedance equivalent value is almost constant and does not change. When train 3 enters the detectable range, as train 3 moves, the distance from the transmission point P2 to the train 3's position (specifically, the short-circuit position between the rails caused by the leading axle) gradually decreases, so the impedance equivalent value gradually decreases. The impedance equivalent value when train 3 reaches the transmission point P2 is almost zero. At this time, the impedance equivalent value is at its minimum value. After train 3 has moved away from (passed) the transmission point P2, the distance from the transmission point P2 to the train 3's position (specifically, the short-circuit position between the rails caused by the trailing axle) gradually increases, so the impedance equivalent value gradually increases. Then, when train 3 moves out of the detection range (when it is not present), the impedance equivalent value becomes almost constant and does not change.

[0033] Thus, the impedance equivalent value as seen from the transmission point is determined according to the train's location relative to that transmission point. Therefore, by pre-determining the correspondence between the train's location and the impedance equivalent value through measurement or other means, the track circuit device 1 can determine the train's location relative to the transmission point.

[0034] Incidentally, since the AC signal transmitted from the transmission point propagates to both sides of the transmission point, the track circuit device 1 needs to determine which of the two detection sections the train has entered (which section is the train-located section) before determining the train's location based on the impedance equivalent value.

[0035] Figures 7 to 11 illustrate the determination of the track occupancy section by the track circuit device 1. Figures 7 to 11 show an example in which of the detection sections, Section 2 and Section 3, is the track occupancy section. The frequency of the AC signal transmitted by track circuit device 1B from transmission point P2 is f2, while the frequencies of the AC signals transmitted by the adjacent track circuit devices 1A and 1C on either side from transmission points P1 and P3 are f1 and f3, respectively, and are different from each other.

[0036] Figure 7 shows the state of no trains in either the detection section (section 2) or section 3. In this state, track circuit device 1B receives both AC signals of frequencies f1 and f3 transmitted by the adjacent track circuit devices 1A and 1C, respectively.

[0037] Next, as shown in Figure 8, train 3 enters the third section. At this point, the left and right rails between transmission points P2 and P3 are short-circuited by the axle of train 3, causing track circuit device 1B to no longer receive the AC signal with frequency f3 transmitted from transmission point P3. More specifically, reception ceases when the leading axle of train 3 passes transmission point P3.

[0038] Next, as shown in Figure 9, train 3 enters the second section. As a result, the left and right rails between transmission points P1 and P2 are short-circuited by the axle of train 3, and the track circuit device 1B stops receiving the AC signal with frequency f1 transmitted from transmission point P1. More specifically, reception stops when the leading axle of train 3 passes transmission point P2. At this time, the trailing axle of train 3 has not yet reached transmission point P2, so the AC signal with frequency f3 remains unreceived.

[0039] Subsequently, as shown in Figure 10, train 3 proceeds into the third section. At this point, track circuit device 1B begins to receive an AC signal with frequency f3 again. More specifically, it begins to be received when the rear axle of train 3 passes the transmission point P2.

[0040] Subsequently, as shown in Figure 11, train 3 proceeds into the second section. At this point, track circuit device 1B begins to receive an AC signal with frequency f1 again. More specifically, the signal is received when the rear axle of train 3 passes the transmission point P1.

[0041] Thus, AC signals transmitted from a transmission point that is farther from the transmission point than the position of train 3 (the position where the rails are short-circuited by the axles of train 3) will not be received at that transmission point. Furthermore, the frequencies of the AC signals transmitted from adjacent transmission points, which are the other boundaries of the detection sections on both sides of the transmission point (adjacent transmission frequencies), are different. For this reason, the track circuit device 1 can determine which of the detection sections is the train-occupied section based on whether or not the AC signals transmitted from adjacent transmission points (adjacent AC signals) have been received. In addition, the timing of the transition between the state in which adjacent AC signals are received and the state in which they are not can be used to determine the timing of the train's entry into the detection section (from an unoccupied section to an occupied section) or departure (from an occupied section to an unoccupied section).

[0042] The impedance equivalent value changes with changes in leakage conductance. The change in leakage conductance refers to the change in the leakage conductance component G=1 / Rb in the equivalent circuits shown in Figures 2 to 4. Leakage conductance is mainly caused by insulation failure between the rails and the ground due to moisture such as rain and snow. When leakage conductance occurs, the leakage conductance component G=1 / Rb in the equivalent circuit increases, decreasing the impedance, and thus the impedance equivalent value decreases.

[0043] Figure 12 illustrates the change in impedance equivalent value due to the occurrence of leakage conductance. However, it is assumed that leakage conductance occurs throughout the entire rail. In Figure 12, the horizontal direction represents the position along the track, the lower side shows the detection sections of the track circuit device 1B, namely the second and third sections and their detectable range, and the upper side shows the correspondence between the train's position and the impedance equivalent value as seen from the transmission point P2 of the track circuit device 1B.

[0044] Furthermore, the diagram illustrates the correspondence between the wire's position and its equivalent impedance by illustrating three different cases with varying amounts of leakage conductance. Specifically, the solid line represents the normal case with almost no leakage conductance, the dashed line represents the case with a small amount of leakage conductance, and the dotted line represents the case with a large amount of leakage conductance.

[0045] Thus, the correspondence between the train's location and the equivalent impedance value changes depending on the amount of leakage conductance generated in the detection section. For this reason, the correspondence between the train's location and the equivalent impedance value is predetermined for each assumed amount of leakage conductance. The track circuit device 1 acquires the equivalent impedance value when the detection section is an unoccupied section where no train is present (unoccupied time), selects the correspondence between the acquired equivalent impedance value and the closest equivalent impedance value as the appropriate correspondence, and determines the train's location in the detection section (occupied section) it has entered based on this correspondence.

[0046] To specifically explain the selection of an appropriate correspondence when a train enters the third section, which is one of the detection sections of track circuit device 1B, track circuit device 1B receives an AC signal of frequency f3 transmitted to the third section from the adjacent track circuit device 1 (track circuit device 1C in Figure 1) when the third section is an unoccupied section where the leading axle of the train has not entered (unoccupied state). Track circuit device 1B constantly monitors this impedance equivalent value when the train is unoccupied, and determines that the third section has entered the train and become an occupied section (occupancy determination) when the train enters the third section, that is, when it stops receiving the AC signal of frequency f3. Upon determining the presence of a train, it selects and adopts the correspondence that is closest to the impedance equivalent value when the train is unoccupied from among the correspondences predetermined for each amount of leakage conductance. This makes it possible to improve the accuracy of determining the train's location based on leakage conductance.

[0047] The correspondence between the track location and the equivalent impedance value, as shown in Figure 12 as an example, may be generated and stored for each track circuit according to its configuration. Alternatively, multiple such correspondences may be generated and stored, associating them with actual running measurements for each temperature, humidity, weather information, etc., and the correspondence that best approximates the weather information at the time of actual use may be adopted and used.

[0048] Figure 13 shows an example of the configuration of the track circuit device 1. The track circuit device 1 comprises a transceiver 10 and a processing unit 30.

[0049] The transceiver 10 transmits a constant level of AC signal via a transmission cable to a transmission point, which is the boundary of a detection section that divides the rails of the track circuit, in accordance with the control of the processing unit 30, and also receives a signal at the transmission point.

[0050] Figure 14 illustrates the configuration of the transceiver 10 and the control of the transceiver 10 by the processing unit 30. The transceiver 10 has an oscillator 11, and the AC signal generated by the oscillator 11 is amplified by an amplifier 12 before being supplied to the transmission point. The oscillation frequency of the oscillator 11 is set by the processing unit 30. The processing unit 30 also sets the oscillation period in which the oscillator 11 oscillates and transmits an AC signal, and the pause period in which the oscillation operation is stopped and no AC signal is transmitted.

[0051] At the transmission point, in addition to the AC signal transmitted by the transceiver 10, AC signals transmitted from adjacent transmission points to the sections on both sides by other adjacent track circuit devices 1 also flow. The current of these AC signals flowing at the transmission point is measured as a received signal by the current sensor 13, amplified by the amplifier 14, and then output to the processing unit 30, as well as output to the processing unit 30 via the bandpass filter 15. The center frequency f0 of the bandpass filter 15 is set by the processing unit 30 to be the oscillation frequency (transmission frequency) of the oscillator 11.

[0052] The processing unit 30 includes a transmission control unit 31, an input / output control unit 32, an impedance equivalent value calculation unit 41, a track occupancy section determination unit 42, a position determination unit 43, a train passage determination unit 44, a passage output unit 45, a correspondence relationship setting unit 46, and a frequency information table 50. Each functional unit of the processing unit 30 can also be configured using a circuit unit that performs signal processing to realize the function, or a calculation processing unit that realizes the function in software.

[0053] The transmission control unit 31 controls the transmission of AC signals by the transceiver 10 so that the AC signals have predetermined transmission levels and transmission frequencies, according to a predetermined frequency information table 50.

[0054] Figure 15 shows an example of the frequency information table 50. In this figure, the values ​​for the track circuit device 1B in Figure 1 are shown as an example. The frequency information table 50 is a data table that defines the frequency of the AC signal transmitted by the device itself and the frequency of the AC signal transmitted by the other track circuit device 1 to the sections on both sides of the transmission point (two detection sections). In other words, for each transmission frequency, it defines the fundamental frequency, the transmission frequency range for which the fundamental frequency may be changed, and the summing frequency.

[0055] The transmission control unit 31 intermittently transmits AC signals. Specifically, during the oscillation period when an AC signal is transmitted, the transceiver 10 transmits an AC signal at the fundamental frequency (f2) defined in the frequency information table 50. During the pause period when no AC signal is transmitted, the frequency of the transmitted AC signal is changed to a frequency that avoids the noise band based on a given noise band included in the received signal received by the transceiver 10. That is, the received signal received by the transceiver 10 during the pause period is subjected to reception level analysis and frequency analysis processing such as FFT (Fast Fourier Transformation) processing to determine the level and frequency (noise band) of noise included in the received signal. Then, based on the determined noise level and frequency (noise band), the transmission frequency is varied within the transmission frequency range (f2±α) defined in the frequency information table 50, for example, to avoid noise frequencies above a certain level, and set as the transmission frequency for the AC signal.

[0056] Furthermore, the transmission control unit 31 switches the frequency of the transmitted AC signal based on the train's location determined by the location determination unit 43. Specifically, it refers to the frequency information table 50 and switches the frequency of the transmitted AC signal (transmission frequency) so that the frequency becomes lower the further the distance from the transmission point to the train's location, and higher the closer the distance. For example, when the detection section is an unoccupied section, the transmission frequency is set to the basic frequency (f2). After the train enters one of the detection sections and becomes an occupied section, and the train's location reaches a predetermined position, the transmission frequency is switched from the basic frequency (f2) to a higher frequency (f2+A), which is the basic frequency (f2) plus an additional frequency (A). Then, when the train passes the transmission point and enters the other detection section, and the train's location reaches a predetermined position, the transmission frequency is switched again from the higher frequency (f2+A) to the basic frequency (f2). In this way, as the train approaches the transmission point, the transmission frequency is switched from a low frequency to a high frequency, and as it passes the transmission point and moves away, the frequency is switched from a high frequency to a low frequency. Since the propagation distance of AC signals differs depending on the transmission frequency and transmission level, it is possible to improve the accuracy of calculating the impedance equivalent value and thus improve the accuracy of determining the train's location.

[0057] Furthermore, while the detection section is within the line-occupied section, the transmission frequency may alternate between the fundamental frequency (f2) and the high frequency (f2+A).

[0058] The input / output control unit 32 controls the input and output of signals to and from external devices, including the track circuit device 1 corresponding to an adjacent transmission point. Signal input and output may be implemented by either wireless or wired communication.

[0059] The impedance equivalent value calculation unit 41 calculates an impedance equivalent value based on the AC signal transmitted from the transmission point.

[0060] Specifically, the waveforms of the transmitted voltage (transmit voltage waveform) and the transmitted current (transmit current waveform) of the AC signal transmitted by the transceiver 10 are quadrature-detected to determine the amplitudes of the transmitted voltage and transmitted current, and the phase difference of the transmitted current relative to the transmitted voltage. Based on these amplitudes and phase differences of the transmitted voltage and transmitted current, an impedance equivalent value is calculated (see Figures 2 to 5).

[0061] The occupancy section determination unit 42 determines whether the sections on both sides of the transmission point are occupancy sections. Specifically, it determines the occupancy section based on the components of the adjacent AC signal transmitted from the adjacent transmission point, which is the other boundary of each of the two sections, contained in the received signal received by the transceiver 10.

[0062] In other words, during periods when the transceiver 10 is not transmitting AC signals, frequency analysis processing such as FFT (Fast Fourier Transformation) is performed on the received signal received by the transceiver 10. The system determines whether or not an adjacent AC signal has been received based on whether or not the received signal contains frequency components within the transmission frequency range defined in the frequency information table 50 as adjacent AC signals for each of the two detection sections. The frequency analysis processing for the received signal may be shared with the frequency analysis processing performed by the transmission control unit 31. For each of the two detection sections, if an adjacent AC signal corresponding to that section is received, the section is determined to be an unoccupied section; otherwise, it is determined to be an occupied section. Furthermore, the timing of the transition between the state in which an adjacent AC signal is received and the state in which it is not received is used to determine the timing of a train's entry into the detection section (from an unoccupied section to an occupied section) or departure (from an occupied section to an unoccupied section) (see Figures 7 to 11).

[0063] Alternatively, the determination of the train occupancy section may be performed based on the train passing signal related to the adjacent transmission point, which is the other boundary of each of the two sections. Specifically, the detection section with the adjacent transmission point as the other boundary is determined to be the train occupancy section based on the train passing signal input from another track circuit device 1 corresponding to the adjacent transmission point via the input / output control unit 32.

[0064] The position determination unit 43 determines the location of the train within the track section relative to the transmission point based on the impedance equivalent value. It also determines the location by referring to the correspondence set by the correspondence setting unit 46.

[0065] Specifically, the system determines the location of a train that occupies a train, according to the correspondence between the train's location and the impedance equivalent value, as defined or set for the detection section which is the section where the train is located (see Figures 6 and 12).

[0066] As described above, the equivalent circuit of the track circuit is composed of the rail inductance component La, the series resistance component Ra, the capacitance component C between rails, and the leakage conductance component G = 1 / Rb, and when the train reaches the transmission point, it becomes the axle short-circuit impedance Rv. That is, as the train approaches the transmission point from an unoccupied state, the rail inductance component La, the series resistance component Ra, and the capacitance component C between rails decrease (see Figures 2, 3, and 4). The impedance of the rail inductance component La and the capacitance component C between rails differs depending on the frequency. Using this characteristic, when a train reaches the detection section, the frequency of the transmitted AC signal is alternately switched between the fundamental frequency (f2) and the high frequency (f2+A). The train's position may then be determined by the difference between the impedance equivalent value when the transmission frequency is the fundamental frequency (f2) and the impedance equivalent value when the transmission frequency is the high frequency (f2+A).

[0067] The train passage determination unit 44 determines whether a train has passed the transmission point based on whether the impedance equivalent value meets a predetermined minimum condition. Specifically, it monitors the time change of the impedance equivalent value and determines that the point in time when the impedance equivalent value is at its minimum is the point in time when a train has passed the transmission point (see Figure 6).

[0068] The passing output unit 45 outputs a train passing signal when the train passing determination unit 44 determines that a train has passed. Specifically, it outputs a train passing signal, along with the time of passing, to an external device including other track circuit devices 1 corresponding to adjacent transmission points, via the input / output control unit 32.

[0069] The correspondence relationship setting unit 46 sets the correspondence relationship between the impedance equivalent value and the location on the track, based on the impedance equivalent value when the location determination unit 42 changes from a state where it is determined not to be a location on the track to a state where it is determined to be a location on the track.

[0070] Specifically, when a train is determined to be in a tracked area after being previously determined not to be in a tracked area, that is, when it is determined that a train is entering the detection area, the system selects and sets the correspondence between the tracked position and the impedance equivalent value that is closest to the impedance equivalent value in the state before the train entered the track, when it was determined not to be in a tracked area (see Figure 12).

[0071] [Effects and Effects] According to this embodiment, in a track circuit device 1 that determines the location of a train based on an AC signal transmitted from a transmission point to the rails, it is possible to improve the accuracy of determining the location of a train by first determining whether the sections on both sides of the transmission point are train-occupied sections, and then determining the location of the train within the train-occupied section relative to the transmission point based on the impedance equivalent value based on the AC signal transmitted from the transmission point.

[0072] [Differentiation] It should be noted that the applicable embodiments of the present invention are not limited to those described above, and can be modified as appropriate without departing from the spirit of the invention.

[0073] (A) Correspondence between the transmission point and the track circuit device In the embodiment described above, one track circuit device is associated with one transmission point. However, one track circuit device may be associated with multiple transmission points, and the track circuit device may transmit AC signals from each of the transmission points.

[0074] In this case, the track circuit device may also employ a so-called scanning method, sequentially switching between multiple transmission points to transmit AC signals. This allows for the selection of transmission points to which AC signals are transmitted while tracking a train. [Explanation of Symbols]

[0075] 1...Track circuit device 10... Transmitter / Receiver 30… Processing equipment 31...Transmission Control Unit 33… Input / Output Control Unit 41...Impedance equivalent value calculation unit 42...Occupied section determination unit 43...Position determination section 44...Train passage determination section 45...pass output section 46... Correspondence relationship setting section 50…Frequency Information Table

Claims

1. A transmitting means that transmits an AC signal from a transmission point which is the boundary of a section of rail to the rail, A means for determining whether the sections on both sides of the aforementioned transmission point are occupied sections, A calculation means for calculating an impedance equivalent value based on the AC signal transmitted from the aforementioned transmission point, A position determination means that determines the location of a train within the track section with respect to the transmission point based on the impedance equivalent value, A track circuit device equipped with the following features.

2. Receiving means for receiving the signal at the aforementioned transmission point, Furthermore, The occupancy section determination means performs the occupancy section determination based on the component of the adjacent AC signal transmitted from the adjacent transmission point, which is the other boundary of each of the two sections, included in the received signal received by the receiving means. The track circuit device according to claim 1.

3. A train passage determination means for determining whether the impedance equivalent value satisfies a predetermined minimum condition and whether a train has passed the transmission point, A train passage output means that outputs a train passage signal indicating that a train has passed when the train passage determination means determines that a train has passed, Furthermore, The occupancy section determination means performs the occupancy section determination based on the train passing signal relating to the adjacent transmission point which is the other boundary of each of the two sections. The track circuit device according to claim 1.

4. Correspondence relationship setting means that sets the correspondence between the impedance equivalent value and the location of the train based on the impedance equivalent value in a state where the train is not in a train location determined by the train location determination means. Furthermore, The position determination means determines the location by referring to the correspondence relationship. The track circuit device according to claim 1.

5. Receiving means for receiving the signal at the aforementioned transmission point, Furthermore, The aforementioned transmission means is The transmission of the aforementioned AC signal is performed intermittently, Based on a given noise band included in the received signal received by the receiving means during a period when the AC signal is not being transmitted, the frequency of the AC signal to be transmitted is changed to a frequency that avoids the noise band. To do The track circuit device according to claim 1.

6. The transmitting means switches the frequency of the AC signal to be transmitted based on the location determined by the location determination means. The track circuit device according to claim 1.

7. A transmitting means that transmits an AC signal from a transmission point which is the boundary of a section of rail to the rail, A means for determining whether the section related to the transmission point is a tracked section, A calculation means for calculating an impedance equivalent value based on the AC signal transmitted from the aforementioned transmission point, A correspondence relationship setting means sets a correspondence relationship between the impedance equivalent value and the location of the train based on the impedance equivalent value in a state where the train is not in a train location determined by the train location determination means. When the aforementioned train location determination means determines that a train is in a train location section, the position determination means determines the location of the train within the train location section with respect to the transmission point, based on the impedance equivalent value and the correspondence relationship. A track circuit device equipped with the following features.

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