Power converter

Abstract

This invention provides a power converter that allows for adjustment of the input voltage (output voltage) at the installation site. [Solution] The power converter 100 is configured to generate multiple AC voltages of different voltages and is equipped with multiple output terminals 113 to 115 so that each of the multiple AC voltages of different voltages can be output externally. At the installation site, level crossing controllers 310 that require a relatively low output voltage are connected to the Lo terminal 113 and COM terminal 116 of the power converter 100 via cables 301 and 302. At the installation site, level crossing controllers 320 that require a standard output voltage are connected to the Mid terminal 114 and COM terminal 116 of the power converter 100 via cables 303 and 304. At the installation site, level crossing controllers 330 that require a relatively high output voltage are connected to the Hi terminal 115 and COM terminal 116 of the power converter 100 via cables 305 and 306.

Description

Technical Field

[0001] The present invention relates to a power converter for a level crossing controller.

Background Art

[0002] At a level crossing where a railway and a road intersect at a flat level, there are usually installed level crossing protection devices such as a level crossing warning device and a level crossing barrier. For the control of such level crossing protection devices, it is necessary to detect the approach and passage of a train (entry of the train into the warning control section and exit of the train from the warning control section), and near the level crossing, as a train detection device, for example, a level crossing controller is installed.

[0003] A level crossing controller is used to detect that a train has approached or passed through a level crossing. It is a kind of short non-insulated track circuit that detects a train by flowing a current of 8.5 to 40 kHz through the rails and utilizing the short-circuit between the rails by the axle of the train. The level crossing controller has a short section (control section) capable of detecting a train, and the length of the control section is 30 m as a standard.

[0004] In addition, level crossing controllers are classified into two types, a closed circuit type and an open circuit type, according to their detection methods. The closed circuit type is used for the alarm start point that detects the entry of a train into the warning control section and starts an alarm. The open circuit type is used for the alarm end point that detects the exit of a train from the warning control section and stops the alarm.

[0005] In recent years, a level crossing controller called "H type" with enhanced train detection ability has become widespread. Among these H-type level crossing controllers, for the closed circuit type (HC type) level crossing controller, since it is laid at a location far (for example, about 1 km) from the level crossing (level crossing equipment box), the cable length becomes long, and voltage drop due to external influence and cable resistance is likely to occur. Therefore, in order to prevent malfunction due to cable interference and reduce losses in the power cable, power transmission to the closed circuit type (HC type) level crossing controller is performed not with direct current but with rectangular wave alternating current (AC200V 400Hz).

[0006] For this AC power transmission, a device called a power converter is typically used. The power converter is an AC power source for closed-circuit type (HC type) level crossing controllers, and is installed, for example, inside a level crossing equipment box. Based on the DC voltage generated inside the level crossing equipment box, it generates an AC signal (square wave signal) for transmitting power to the closed-circuit type (HC type) level crossing controller.

[0007] Incidentally, the output voltage of a power converter fluctuates depending on the connected load and input voltage. Therefore, the power supply voltage (contact voltage) reaching the closed-circuit type (HC type) level crossing controller also fluctuates depending on the connected load and input voltage. Furthermore, recently, additional equipment (e.g., level crossing backup devices and lightning protection transformers) has been connected between the power converter and the level crossing controller, and the contact voltage also fluctuates due to the influence of such equipment. In addition, multiple level crossing controllers (e.g., up to 4) can be connected to the output terminal of the power converter, but when multiple level crossing controllers are connected, the contact voltage of each level crossing controller will usually differ due to differences in cable length, etc. As a result, depending on the installation site, the contact voltage may not fall within the voltage range specified in the maintenance and inspection standards (e.g., AC 190~230V). Furthermore, even if the onset voltage was within the voltage range specified in the maintenance and inspection standards (e.g., AC 190-230V), the relay drive voltage generated and output by the level crossing controller based on the onset voltage sometimes did not fall within the voltage range specified in the maintenance and inspection standards (e.g., DC 22.5-28V).

[0008] However, conventional power converters only output one predetermined AC power voltage and do not allow for adjustment of the output voltage at each installation site, making it difficult to adjust the input voltage at each installation site.

[0009] Furthermore, Japanese Patent Publication No. 2020-93585 describes a power converter that converts a DC voltage rectified by a rectifier into an AC voltage and supplies it to a level crossing controller, and equipment that constitutes a level crossing backup device fault detection unit, which includes a backup fault transmitter and a backup fault receiver connected between the power converter and the level crossing controller. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Japanese Patent Publication No. 2020-93585 (paragraphs 0038-0041, Figure 12) [Overview of the project] [Problems that the invention aims to solve]

[0011] The object of the present invention is to provide a power converter that allows adjustment of the charging voltage (output voltage) at the installation site. [Means for solving the problem]

[0012] The power converter according to the present invention is characterized by comprising a voltage generation unit that generates a plurality of AC voltages with different voltages, and a plurality of output terminals for outputting each of the plurality of AC voltages.

[0013] In this case, a common output terminal may be provided that is used in conjunction with each of the aforementioned multiple output terminals.

[0014] In the above case, the voltage generation unit is composed of a transformer equipped with an input coil and an output coil, and the output coil is equipped with a plurality of connection terminals connected at a plurality of positions with different numbers of turns, and each of the plurality of connection terminals is connected to the corresponding output terminal of the plurality of output terminals.

[0015] Alternatively, the voltage generation unit may be composed of a transformer equipped with an input coil and an output coil, wherein the output coil comprises a first set of connection terminals connected to a plurality of positions with different numbers of turns on one end, and a second set of connection terminals connected to a plurality of positions with different numbers of turns on the other end, each of the first set of connection terminals connected to the corresponding output terminal of the plurality of output terminals, and any one of the second set of connection terminals connected to the common output terminal. [Effects of the Invention]

[0016] According to the present invention, it is possible to adjust the charging voltage (output voltage) at the installation site. [Brief explanation of the drawing]

[0017] [Figure 1] This is a diagram illustrating the external appearance of the power converter 100 according to the present invention. [Figure 2] This figure shows an enlarged front view of the terminal block 110 of the power converter 100. [Figure 3] This diagram illustrates the connection between the power converter and the level crossing controller. [Figure 4] This is a block diagram illustrating an example of the internal hardware configuration of the power converter 100. [Figure 5] This is a circuit diagram showing the output transformer 450 and its surrounding circuitry. [Modes for carrying out the invention]

[0018] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0019] The power converter according to the present invention is an AC power supply for a closed-circuit type (HC type) switch controller, and generates an AC voltage (rectangular wave voltage) for supplying power to the HC type switch controller (hereinafter simply referred to as the "switch controller") based on a DC voltage input from the outside. The power converter according to the present invention is configured to be able to generate a plurality of AC voltages with different voltages, and includes a plurality of output terminals so that each of the plurality of AC voltages with different voltages can be output to the outside.

[0020] FIG. 1 is a diagram for explaining the appearance of the power converter 100 according to the present invention. FIG. (a) of the same figure shows a front view, and FIG. (b) of the same figure shows a right side view.

[0021] As shown in the figure, the power converter 100 according to the present invention has a generally rectangular parallelepiped shape, and includes a terminal block 110 and a display unit 120 on the front side. In addition, in the present embodiment, the power converter 100 is formed in a shape suitable for installation in a switchgear box provided near each switch.

[0022] The terminal block 110 includes a plurality (six in this embodiment) of terminals for connecting input and output cables. Details of the terminal block 110 will be described later.

[0023] The display unit 120 is for displaying various states of the power converter 100, and in this embodiment, is composed of two light-emitting diodes (LEDs), specifically, a power supply LED 121 and an output LED 122.

[0024] The power supply LED 121 indicates the power-on state and lights up when a DC voltage is input to the power converter 100.

[0025] The output LED 122 indicates the output state of the AC voltage and lights up when an AC voltage is output from the power converter 100.

[0026] FIG. 2 is a diagram showing an enlarged front view of the terminal block 110.

[0027] As shown in the figure, the terminal block 110 is equipped with a plurality of terminals (six in this embodiment) 111 to 116. More specifically, it is equipped with a pair of input terminals 111 and 112 and a plurality of output terminals (four in this embodiment) 113 to 116.

[0028] The pair of input terminals 111 and 112 are terminals for inputting a DC voltage to the power converter 100 from an external source, and are connected, for example, to a DC power supply provided inside the level crossing equipment box via a cable. In this embodiment, the positive (+) side of the DC voltage is connected to one input terminal 111, and the negative (-) side of the DC voltage is connected to the other input terminal 112.

[0029] Multiple output terminals 113 to 116 are terminals for outputting AC voltage (square wave voltage) to supply power to the level crossing controller, and are connected to the level crossing controller, for example, via a cable. In this embodiment, in order to output three AC voltages of different voltages, there are Lo terminal 113, Mid terminal 114, Hi terminal 115, and COM terminal 116.

[0030] The Lo terminal 113 is a terminal that outputs a voltage lower than the standard voltage (AC200V), and is used, for example, when a relatively low output voltage is required at the installation site. In this embodiment, it outputs a voltage 5% lower than the standard voltage.

[0031] The Mid terminal 114 is a terminal that outputs a standard voltage (AC200V) and is used, for example, when a standard output voltage is required at the installation site.

[0032] The Hi terminal 115 is a terminal that outputs a voltage higher than the standard voltage (AC200V), and is used, for example, when a relatively high output voltage is required at the installation site. In this embodiment, it outputs a voltage 5% higher than the standard voltage.

[0033] COM terminal 116 is a common output terminal used in pairs with Lo terminal 113, Mid terminal 114, and Hi terminal 115. When a relatively low output voltage is required, Lo terminal 113 and COM terminal 116 are connected to the AC power input terminal of the level crossing control unit via a cable. When a standard output voltage is required, Mid terminal 114 and COM terminal 116 are connected to the AC power input terminal of the level crossing control unit via a cable. When a relatively high output voltage is required, Hi terminal 115 and COM terminal 116 are connected to the AC power input terminal of the level crossing control unit via a cable.

[0034] Figure 3 illustrates the connection between the power converter and the level crossing controllers. The example shown in the figure illustrates the case where three level crossing controllers are connected to one power converter.

[0035] As shown in the figure, the power converter 100 is connected to three level crossing controllers 310, 320, and 330 via cables 301 to 306. More specifically, the power converter 100 is connected to the first level crossing controller 310 via a pair of cables 301 and 302, to the second level crossing controller 320 via a pair of cables 303 and 304, and to the third level crossing controller 330 via a pair of cables 305 and 306.

[0036] The first level crossing controller 310 is installed relatively close to the power converter 100. When connected to a conventional power converter (or the Mid terminal 114 of this device), the on-board voltage and relay drive voltage become higher than the voltage range specified in the maintenance and inspection standards. Therefore, in the example shown in the figure, the first level crossing controller 310 is connected to the Lo terminal 113 (and COM terminal 116) of the power converter 100 to make the on-board voltage and relay drive voltage relatively lower.

[0037] The second level crossing controller 320 is installed at a location relatively farther from the power converter 100 compared to the first level crossing controller 310, and when connected to a conventional power converter, the on-board voltage and relay drive voltage fall within the voltage range specified in the maintenance and inspection standards. Therefore, in the example shown in the figure, the second level crossing controller 320 is connected to the Mid terminal 114 (and COM terminal 116) of the power converter 100 so that the on-board voltage and relay drive voltage are the same as before.

[0038] The third level crossing controller 330 is located furthest from the power converter 100 compared to the first and second level crossing controllers 310 and 320. When connected to a conventional power converter (or the Mid terminal 114 of this device), the on-board voltage and relay drive voltage become lower than the voltage range specified in the maintenance and inspection standards. Therefore, in the example shown in the figure, the third level crossing controller 330 is connected to the Hi terminal 115 (and COM terminal 116) of the power converter 100 to make the on-board voltage and relay drive voltage relatively higher.

[0039] Next, the internal configuration of the power converter 100 will be described.

[0040] Figure 4 is a block diagram illustrating an example of the internal hardware configuration of the power converter 100.

[0041] As shown in the figure, the power converter 100 includes an oscillation circuit 410, a power amplifier 420, overshoot reduction circuits 431 and 432, a current detection and overload protection circuit 440, and an output transformer 450. For simplicity, the power LED 121 and output LED 122 are omitted in the figure.

[0042] The oscillator circuit 410 generates a square wave signal at a predetermined frequency (400 Hz in this embodiment). In this embodiment, the oscillator circuit 410 outputs a pair of square wave signals 411 and 412, one of which is an inverted signal of the other (their phases are 180° apart).

[0043] The power amplifier 420 amplifies each of the pair of square wave signals 411 and 412 generated by the oscillator circuit 410 and outputs them as a pair of amplified square wave signals 421 and 422. In this embodiment, the power amplifier 420 is composed of transistors.

[0044] The overshoot reduction circuits 431 and 432 reduce overshoot in the rising edge of each of the pair of square wave signals 421 and 422 amplified by the power amplifier 420. Furthermore, since some additional equipment connected between the power converter and the level crossing controller may not function properly if the rising edge of the square wave signal is too steep, the overshoot reduction circuits 431 and 432 also serve to slightly smooth the rising edge of the pair of square wave signals 421 and 422 to accommodate such additional equipment.

[0045] The current detection and overload protection circuit 440 detects the current flowing through the device and, when it detects an overcurrent exceeding a certain level (for example, 300% or more of the rated load), it stops the output of the oscillation circuit 410 to protect the device.

[0046] The output transformer 450 is a step-up transformer that generates the voltage necessary to operate the level crossing controller based on a pair of square wave signals 421 and 422 amplified by the power amplifier 420. The output transformer 450 constitutes a voltage generation unit that generates multiple AC voltages of different voltages, and in this embodiment, it is configured to generate three AC voltages of different voltages. The three generated AC voltages are output to the outside via the corresponding output terminals 113 to 115 (and output terminal 116).

[0047] Figure 5 is a circuit diagram showing the output transformer 450 and its surrounding circuits.

[0048] As shown in the figure, the output transformer 450 includes an input coil 451 as a primary coil and output coils 452 and 453 as secondary coils.

[0049] The input coil 451 is a primary coil to which a pair of square wave signals 421 and 422 are input, and is equipped with three connection terminals 511 to 513. The first connection terminal 511 and the third connection terminal 513 are connected to both ends of the input coil 451, while the second connection terminal 512 is connected to the position where the number of turns of the input coil 451 is half.

[0050] The first connection terminal 511 and the third terminal 513 of the input coil 451 are connected to a pair of square wave signals 421 and 422, which have been amplified by the power amplifier 420, respectively. In addition, the second connection terminal 512 of the input coil 451 is connected to a DC voltage (for example, +24V) that is input from an external source via the input terminal 111.

[0051] The first output coil 452 is a secondary coil for outputting multiple (three in this embodiment) AC voltages of different voltages, and is equipped with three connection terminals 521 to 523 provided on one end of the first output coil 452 (the upper end in Figure 5) and four connection terminals 524 to 527 provided on the other end of the first output coil 452 (the lower end in the same figure).

[0052] The three connection terminals 521 to 523 provided on one end of the first output coil 452 are connected to the Hi terminal 115, Mid terminal 114, and Lo terminal 113, respectively. On the other hand, of the four connection terminals 524 to 527 provided on the other end of the first output coil 452, one of them (in the example shown in the figure, the fifth connection terminal 525) is connected to the COM terminal 116.

[0053] The three connection terminals 521 to 523 provided on one end of the first output coil 452 are terminals for outputting three AC voltages of different voltages, and each is connected to a position with a different number of turns on one end of the first output coil 452. More specifically, the first connection terminal 521 is connected to a position with a number of turns that outputs a relatively high voltage (in this embodiment, one end of the output coil 452), the second connection terminal 522 is connected to a position with a number of turns that outputs a voltage lower than that of the first connection terminal 521 and higher than that of the third connection terminal 523, and the third connection terminal 523 is connected to a position with a number of turns that outputs a voltage lower than that of the second connection terminal 522.

[0054] The four connection terminals 524 to 527 provided on the other end of the first output coil 452 are, for example, terminals for adjusting the output voltage value at the time of factory shipment, and are each connected to different positions with different turn counts on the other end of the first output coil 452. More specifically, the fourth connection terminal 524 is connected to a turn count position that outputs a relatively low voltage, the fifth connection terminal 525 is connected to a turn count position that outputs a voltage higher than the fourth connection terminal 524 and lower than the sixth connection terminal 526, the sixth connection terminal 526 is connected to a turn count position that outputs a voltage higher than the fifth connection terminal 525 and lower than the seventh connection terminal 527, and the seventh connection terminal 527 is connected to a turn count position that outputs a voltage higher than the sixth connection terminal 526 (in this embodiment, the other end of the output coil 452).

[0055] The second output coil 453 is a secondary coil for lighting the output LED 122, and is equipped with a pair of connection terminals 531 and 532 at both ends, and the pair of connection terminals 531 and 532 are connected to the output LED 122 via a resistor 501.

[0056] When a pair of square wave signals 421 and 422 are input to the input coil 451 and the first output coil 452 outputs a voltage, the second output coil 453 also outputs a voltage. Therefore, the output LED 122 will light up while the first output coil 452 is outputting a voltage, that is, while the power converter 100 is outputting a voltage.

[0057] Furthermore, as shown in Figure 5, input terminals 111 and 112 are connected to the power LED 121 via resistor 502, and the power LED 121 lights up when an external DC voltage is input via input terminals 111 and 112.

[0058] As described above, the power converter according to the present invention is equipped with multiple output terminals that output multiple AC voltages of different voltages. For example, at the installation site, by selecting and using an output terminal suitable for each level crossing controller from among the multiple output terminals, it is possible to adjust the AC output voltage supplied to the level crossing controller, and as a result, it is also possible to adjust the on-board voltage and relay drive voltage.

[0059] While embodiments of the present invention have been described above, it goes without saying that the embodiments of the present invention are not limited to those described above. For example, in the embodiments described above, there were three output terminals that output three AC voltages with different voltages, but it is also conceivable to have two or four or more terminals that output two or four or more AC voltages with different voltages. [Explanation of Symbols]

[0060] 100 Power Converters 110 Terminal block 111,112 DC voltage input terminals 113 Lo terminal 114 Mid terminal 115 Hi terminal 116 COM terminal 120 Display section 121 Power LED 122 Output LEDs 301-306 Cable 310, 320, 330 Level crossing controller 410 Oscillator Circuit 420 Power Amplifier 431,432 Overshoot Reduction Circuit 440 Current detection and overload protection circuit 450 Output Transformer 451 Input Coil 452,453 Output coil 501, 502 resistors 511~513, 521~527, 531, 532 Connection terminals

Claims

1. A voltage generation unit that generates multiple AC voltages with different voltages, Multiple output terminals for outputting each of the aforementioned multiple AC voltages A power converter characterized by having the following features.

2. The system further includes a common output terminal used in conjunction with each of the aforementioned multiple output terminals. The power converter according to feature 1.

3. The voltage generation unit is composed of a transformer equipped with an input coil and an output coil. The output coil is equipped with multiple connection terminals connected to multiple positions with different numbers of turns, Each of the aforementioned plurality of connection terminals is connected to the corresponding output terminal of the plurality of output terminals. The power converter according to claim 1 or 2.

4. The voltage generation unit is composed of a transformer equipped with an input coil and an output coil. The output coil is A first set of multiple connection terminals connected to multiple positions with different winding counts on one end, A second set of connection terminals connected to multiple positions on the other end with different winding counts, and Equipped with, Each of the first plurality of connection terminals is connected to the corresponding output terminal of the plurality of output terminals, Any one of the second set of connection terminals is connected to the common output terminal. The power converter according to feature 2.

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