JP2946432B2 - Phase detector - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a phase detecting apparatus for detecting the presence or absence of a train in a block section of interest on a rail of a railway.

[0002]

2. Description of the Related Art Conventionally, in order to perform train control or signal control, a rail is divided into predetermined closed sections, and it is detected whether or not a train exists in each closed section.
In this method, a signal synchronized with the frequency of the commercial power supply is supplied from the power transmitting end to the rail, the signal is received at the power receiving end, and the signal is compared with the phase of the commercial power supply.

[0003] With this configuration, when a train enters the closed section, the rail is short-circuited on the axle of the train, and the phase of the received signal changes greatly. By detecting this phase change, it is detected that a train has entered the closed section.

[0004] Basically, this configuration may be used, but when a commercial power supply is supplied to the rail, it is guided by a commercial power supply used in the surroundings, causing inconvenience such as malfunction. For this reason, the frequency of the signal supplied to the rail from the power transmission end is divided by the commercial power supply so as not to be affected by the surrounding commercial power supply.
The frequency is different from the frequency of the commercial power supply used in the surroundings. Then, on the power receiving side, the frequency of the received signal is multiplied and returned to the commercial power frequency, and then phase comparison is performed to detect a phase shift.

[0005] Further, when there is no train in the closed section for detecting the phase shift, as shown in FIG. 4, the phase of the received signal in (a) and the reference signal in (b) become 90 degrees. And the two signals are supplied to the signal winding of the track relay and the local winding, respectively.
The maximum operating torque is generated in the vane at the time.

[0006]

However, such a conventional apparatus has a problem that the apparatus is increased in size because it is necessary to provide a frequency multiplier on the power receiving side. In addition, there is also a problem that the track relay frequently moves in small steps due to the high-frequency component induced on the rail, thereby shortening the life of the track relay.

In order to solve such a problem, a mechanical operation such as a relay is performed and phase detection is not performed. Instead, as proposed by the applicant of the present application in Japanese Patent Application No. 62-29391, an electronic system is used. Thus, it is conceivable to correlate the received signal with the reference phase signal.

This is to compare the received signal shown in FIG. 5 (a) with the reference phase signal shown in FIG. 5 (b), and if the two levels match as shown in FIG. 5 (c). 0, and 1 if different, count 0 and 1 in a fixed sample number n, and
The ratio between the number of n and n is determined as a correlation value. Then, when the correlation value is 50, the relay is operated,
The relay is operated at DC.

FIG. 6 shows this relationship.
As can be seen from this figure, a phase difference of 90 degrees has a correlation value of 50. That is, if the correlation value is 50, there is a train on the forward track, and if the correlation value is 0 or 100, there is no train ahead.

However, when one of the signals cannot be obtained as shown in FIG. 7, or when an even-numbered signal is induced in one of the two signals as shown in FIG. Therefore, the orbit relay operates even though the phase difference is not 90 degrees.

[0011]

According to the present invention, there is provided a reference phase signal for generating two kinds of reference phase signals having a phase difference of 90 degrees by dividing a commercial power supply. When the correlation between the generator and one reference phase signal and the received signal is close to 50 and the correlation between the other reference phase signal and the received signal is close to 0 or 100, one of the two types of reference phase signals A phase determination circuit that determines that the phase difference between the signal and the received signal is close to 90 degrees.

[0012]

When the correlation value is 50, only a signal having a phase difference of 90 degrees is detected.

[0013]

FIG. 1 is a block diagram showing an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a power transmitting end device, 2 denotes a power receiving side device, 3 denotes a rail, and symbol A denotes a closed section. However,
The elements shown by solid lines are elements used in one block section described here, and the parts shown by dotted lines are elements for adjacent block sections.

The power transmitting end device 1 includes a band-pass filter (BPF) 10 that outputs only the frequency component of the commercial power, a processing unit 11 that divides the frequency of the commercial power to generate a transmission signal of, for example, 25 Hz, an amplifier 12, a resistor, 13, a capacitor 14, and an impedance bond 15 for supplying a transmission signal to the rail 3 and ensuring isolation from an adjacent closed section.

The power receiving terminal device 2 is an impedance bond 2
5, a capacitor 24, a resistor 23, an attenuator 22, a processing unit 21, a bandpass fill 20, and a track relay 26. The processing unit 21 of the power receiving end device 2 divides the frequency of the commercial power supply, compares the frequency with the phase of the received signal, and operates the track relay 26 based on the comparison result. Although the processing units 11 and 21 describe only necessary functions, both have the same functions.

FIG. 2 is a block diagram showing the internal configuration of the processing unit 21, wherein 21a, 21b and 21c denote inverters for inverting the signal of the commercial power supply, and 21d and 21e divide the frequency of the commercial power supply by half. The frequency divider 21d generates a first reference phase signal, and the frequency divider 21e generates a second reference phase signal.

One of the first and second reference phase signals has a phase difference of 90 degrees from the reception signal when the rail is not short-circuited, that is, when the train is not on the closed section. Is set to

Reference numeral 21f denotes a first correlator for obtaining a correlation based on a phase difference between the first reference phase signal and the received signal, and 21g denotes a second correlator for obtaining a correlation based on the phase difference between the second reference phase signal and the received signal. A correlator 21h is a phase determination circuit that determines whether the input signal and the reference phase signal are actually 90 degrees or 0 degrees based on the output signals of the correlators 21f and 21g, and 21i is a received signal. Is a train determination circuit that determines whether or not the train is on the closed section from the output signal of the phase determination circuit 21h and the output signals of the first and second correlators on condition that there is a level of the train.

In the device configured as described above, the correlator 21f and the input signal show the correlation shown in FIG. 3A, and the correlator 21g and the input signal show the correlation shown in FIG. 3B. here,
Since the frequency dividers 21d and 21e divide signals having phases different by 180 degrees, the output signals of the respective frequency dividers have a phase difference of 90 degrees.

The fact that the received signal and the reference phase signal are 90 degrees means that the relationship shown in FIG. 4 is established. By the way, as described above, one of the reference phase signals is
Since it is set to have a phase difference of 0 degrees, the first
As shown in FIG. 4, when the second reference phase signal has a phase difference of 90 degrees, when one train is normal in the closed section, one of the reference phase signals has a correlation with the reception signal. Is 50, but the correlation between the other reference phase signal and the received signal is 0 or 100.

That is, when the correlation between one reference phase signal and the received signal is 0 or 100 and the correlation between the other reference phase signal and the received signal is 50, the reference phase signal and the received signal are both satisfied. Is a state in which the state where the phase difference is 90 degrees and the correlation is 50 is accurately detected.

In other cases, even if the correlation is 50
, The phase difference between the reference phase signal and the received signal is 90
It will not be a degree. Therefore, there is no erroneous determination when there is no one signal as shown in FIG. 7 and when one signal has an even multiple of the frequency of the reference phase signal as shown in FIG.

The correlator 21f generates an output B corresponding to a predetermined range indicated by the symbol "a" in FIG. 3A including the correlation value 50 and an output A or C corresponding to the other range. . Output B has a correlation between the received signal and the reference phase signal, and output A or C indicates that there is no correlation between the received signal and the reference phase signal. Therefore, it is only necessary to be able to distinguish between the output B and the output A and the output B and the output C. Therefore, the output A and the output C are at the same level, and the output B is at a different level. Is output.

The same applies to the correlator 21g. The output D and the output F are at the same level, and the output E is at a different level. And these A to F
, The phase determination circuit 21g determines that the received signal and the reference phase signal have the relationship shown in Table 1.

[0025]

This makes it possible to accurately detect that the correlation is 50 and the phase difference between the received signal and the reference phase signal is 90 degrees. In this way, the relationship between the correlation and the phase is determined, but the train determination circuit 21i checks the relationship between the phase and the level for further safety. This is the case where the phase difference between the received signal and the reference phase signal is 0 degree, and 90 degrees.
In the case of the degree, the determination as shown in Table 2 is performed in combination with the presence or absence of the received signal.

[0027]

Therefore, it is possible to accurately determine that there is a train only when the phase difference is 90 degrees and the level of the received signal is present.

[0029]

As described above, according to the present invention, two kinds of reference phase signals having a phase difference of 90 degrees are generated in the receiving end device, and one of the two signals is generated when the rail is not short-circuited. Is set so as to have a phase difference of 90 degrees, so that when the detection of the phase difference is digitized, it is erroneously determined that there is a phase difference of 90 degrees even when there is no one signal. Therefore, there is an effect that downsizing can be achieved by digitization.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a block diagram showing the internal configuration of the device shown in FIG.

FIG. 3 is a graph showing the operation of the correlator in FIG. 2;

FIG. 4 is a diagram showing a relationship between a received signal and a reference phase signal.

FIG. 5 is a diagram showing a correlation between a received signal and a reference phase signal.

FIG. 6 is a diagram illustrating a relationship between a correlation value and a phase difference between a received signal and a reference phase signal.

FIG. 7 is a diagram showing an abnormal state of a received signal.

FIG. 8 is a diagram showing an abnormal state of a received signal.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Power transmitting end device 2 Power receiving end device 3 Rail 10,20 BPF 11,21 Processing part 13,23 Resistance 14,24 Capacitor 15,25 Impedance bond 26 Track relay

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-1-136870 (JP, A) JP-A-1-104858 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) B61L 1/18 JICST file (JOIS)

Claims (1)

(57) [Claims] 1. A method for detecting whether or not a phase difference between a phase of a signal obtained by dividing a commercial power supply transmitted via a rail at a power receiving end and a reference phase signal obtained from the commercial power supply is 90 degrees. In a phase detection device, a reference phase signal generator that divides a commercial power supply and generates two types of reference phase signals having a phase difference of 90 degrees from each other; Close, and when the correlation between the other reference phase signal and the received signal is close to 0 or 100, the phase difference between one of the two types of reference phase signals and the received signal is close to 90 degrees. A phase detection circuit, comprising: a phase determination circuit for determining.