RU2517631C2 - Receiving device for automatic cab signalling - Google Patents

Abstract

FIELD: physics, signalling.

SUBSTANCE: invention relates to railway automation and telemechanics and improves noise-immunity of automatic cab signalling. Use of the invention broadens functional capabilities of receiver coils. The receiving device for automatic cab signalling includes receiver coils connected through a connecting cable to a cab receiver. The solenoid coil is partitioned to reduce intrinsic capacitance of the receiver coil. Inductance and intrinsic capacitance of the coils, as well as capacitance of the connecting cable and the input capacitance of the receiving device provide resonance of the receiving circuit at carrier frequency of the automatic cab signalling signal.

EFFECT: design of said receiving device considerably improves noise-immunity and reliability of receiving and identifying an automatic cab signalling code on a train.

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Description

The invention relates to the field of automation in railway transport and is used in signal reception systems of automatic locomotive signaling (ALS) due to inductive coupling with rails of a railway track.

Known receiving device for automatic locomotive signaling according to patent No. 59010, class. B61L 25/06, which contains counter-coupled locomotive receiving coils, a traction current harmonic filtering circuit, and an input signal correction circuit.

The disadvantage of this device is the significant inductance and intrinsic capacitance of locomotive receiving coils, which, together with the capacitance of the connecting cable and the capacitance of the input stage of the ALS locomotive equipment, form a resonance in the low-frequency region, distorting the pattern of traction current harmonics and interfering with the operation of the correction circuit.

Closest to the technical nature of the claimed invention is the "Diagnostic system for locomotive equipment of automatic locomotive signaling and receiving locomotive coil" according to patent No. 2383460, adopted as a prototype.

The diagnostic system for locomotive equipment ALS automatic locomotive signaling includes receiving locomotive coils connected to the locomotive equipment ALS, and diagnostic equipment. The receiving locomotive coil consists of a magnetic core with the main and additional galvanically isolated diagnostic windings.

The disadvantage of this device is the significant value of the inductance and the own inter-turn capacitance of the receiving locomotive coils, which together with the capacity of the connecting cable and the capacity of the input stage of the locomotive equipment of the ALS form a resonance in the low-frequency region, which interferes with the reception of ALS signals with a frequency above the resonant.

The task of the invention is to reduce the equivalent capacity of the receiving locomotive coil, which allows to expand the frequency properties of the receiving path of the automatic locomotive signaling equipment. Extending the passband of the receiving path allows you to apply a higher carrier frequency of the ALS signal and work in the frequency range with a lower level of interference from the traction current.

The technical result achieved by the implementation of the invention is expressed in increasing the noise immunity of the receiving device ALS on the train.

The specified technical result is achieved as follows. The receiving device for automatic locomotive signaling includes receiving coils connected via a connecting cable to the locomotive receiver. In each of the receiving coils containing a ferromagnetic core and a solenoid located on it, the winding of the solenoid is made sectioned. Sectioning the solenoid winding significantly reduces the self-capacitance of the receiving coils. As a result, the resonance determined by the inductance and self-capacitance of the coils, as well as the capacitance of the connecting cable and the input capacitance of the receiving device, is shifted to the high-frequency region, expanding the possibilities of using higher carrier frequencies of the ALS signal. To obtain maximum noise immunity, the carrier frequency of the automatic locomotive signal is set equal to the resonant frequency of the receiving path.

Figure 1 schematically shows a General view of the receiving coil. The coil comprises a housing 1 with a connector 2 fixed thereon, a ferromagnetic core 3 and a solenoid 4 located on it. The coil of the solenoid is shown partitioned with the formation of 4 sections.

The circuit of the receiving device ALS on the train is shown in figure 2. Two receiving coils 5 located perpendicular to the running rails 6, connected in series with each other, with a cable 7 are connected to the input of the locomotive receiver 8. The receiving coils 5 are fixed to the carriage of the car in front of the first wheelset 9 in the direction of travel, due to which continuous inductive coupling of train devices with track devices. The receiving coils are connected sequentially and counterclockwise so that the EMF induced by the traction current propagating along the rails in one direction is subtracted, and the EMF induced by the signal current propagating along the rails in different directions is added.

A feature of the receiving coil is a significant value of the inductance, which determines the magnitude of the induced emf and the required signal level at the input of the locomotive receiver. The required coil inductance is achieved by winding a large number (several thousand) turns of copper wire. A large number of turns of the receiving coil is accompanied by a significant in-turn capacitance, which limits its use at higher frequencies. The cable capacitance and the input capacitance of the locomotive receiver are added to the inter-turn capacitance of the receiving coil. The total effect of their own inter-turn capacitance and stray capacitances in the receiving path of the receiving coil used on the subway (TU-400-11-006-94) leads to resonance at a frequency of about 1.5 kHz, which excludes the reception of signals with a frequency above this value. Of the capacities affecting the resonance, the intrinsic winding capacitance of the receiving coil is dominant in magnitude. One of the common methods for reducing the self-capacitance of inductors is winding sectioning. Sectioning the solenoid winding reduces the equivalent capacitance of the receiving coil, increases the resonant frequency of the receiving path, providing the possibility of increasing the carrier frequency of the ALS signal.

The receiving device automatic locomotive alarm operates as follows.

When the train moves along the rails, reverse traction current and ALS current generated by floor station devices flow. These currents induce electrical signals in the receiving coils, which are amplified by the resonant receiving path tuned to the carrier frequency of the ALS signal and are suppressed outside the passband of the resonant receiving path. The input of the locomotive receiver receives the initially filtered mixture of the useful signal and interference, which is fed to the locomotive receiver for processing. Increasing the carrier frequency of the ALS signal gives an additional gain in signal-to-noise ratio due to the departure from powerful low-frequency harmonics of the traction current.

Sectioning of locomotive coils moves the resonant frequency of the receiving path to the area where interference from the traction current is less pronounced, which increases the noise immunity of the device.

The receiving coil can be implemented within the framework of the “Motion” system (Kuznetsov S.V. et al., “The Motion” system: stationary equipment, a central post and a single radio communication system ”, Modern Automation Technologies, 2001, No. 2). A feature of the ALS signal of the Motion system is the relatively high carrier frequency of the coding signal of the automatic locomotive signaling - 3348 Hz. Direct measurements showed that known receiving coils provide a receiving path with a resonant frequency of 1.5 kHz (figure 3, curve 10). Sectioned receiving coils have a resonance of the receiving path at a frequency of 3.5 kHz (figure 3, curve 11). At the same time, the sensitivity at a frequency of 3348 Hz is 2 times higher, and low-frequency noise is 1.9 times lower, which ensures stable reception of the ALS signal on the train.

Thus, the partitioned implementation of the winding of the receiving coil solenoid and the fulfillment of the conditions for ensuring the resonance of the receiving path at the carrier frequency of the ALS signal can achieve a significant increase in the noise immunity of the ALS receiver on the train.

Claims (1)

A receiving device for automatic locomotive signaling, including receiving coils connected through a connecting cable to a locomotive receiver, each of which contains a ferromagnetic core and a solenoid located on it, characterized in that the solenoid winding is made sectioned, with the magnitude of the inductance and intrinsic capacity of the coils, as well as the capacitance the connecting cable and the input capacitance of the locomotive receiver ensure the resonance of the receiving path at the carrier frequency of the signal automatically th locomotive signaling.

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