Test device for current collectors

Abstract

Test device including: a test unit (400) mounted on a pantograph (330) of a rail vehicle for inspecting the condition of the pantograph (330), a power supply unit (600) which supplies power to the test unit (400), and a harvester unit (500) provided on the pantograph (330), which collects electrical energy from the pantograph (330) and supplies it to the power supply unit (600); wherein the harvester unit (500) comprises a magnetic field harvester (100) attached to a conductor rail (L) of the current collector (330) with a core (110) provided outside the conductor rail (L) and a coil (120) wound on the core (110); and wherein the power supply unit (600) is designed with a core stabilization circuit (670) to reduce saturation of the core (110), wherein the core stabilization circuit (670) comprises a resistor (672) provided in parallel to the output of the magnetic field harvester (100), a first switch (674) connected in series with the resistor (672) and a second switch (676) connected in series with the output of the magnetic field harvester (100).

Description

Technical area

[0001] The present invention relates to a testing device for a pantograph. Specifically, current is collected from an electromagnetic field generated by current supplied to the pantograph and stored in a rechargeable battery. The described pantograph testing device can be used as a power source for a testing unit, thereby reducing maintenance costs and preventing work-related accidents when replacing discharged batteries. Technical background

[0002] Due to constant physical contact, the pantograph and overhead line on rail vehicles wear out over time. In the event of a collision or an arc flash due to a loss of contact, localized damage can occur with varying degrees of severity. Damage to the pantograph is usually easily visible to the naked eye during a vehicle inspection, whereas an examination of the overhead line is difficult due to its length and inaccessible location.

[0003] Traditionally, to detect collision damage, etc., a control device was installed on inspection vehicles specifically to determine the exact position and degree of damage in the event of irregularities between the pantograph and the overhead line. However, since inspection vehicles follow a fixed inspection cycle, faults cannot be detected in real time.

[0004] If an inspection vehicle is used, the condition of the overhead line can be determined, but the condition of the pantographs installed on the vehicles traveling on that line cannot be checked.

[0005] A method has recently been developed that records the condition of the overhead line and pantograph in real time by mounting an additional test device on the rail vehicle. Among other features, the test device incorporates a shock sensor mounted directly on the pantograph's contact strips. This has the advantage of detecting irregularities with high sensitivity. However, the disadvantage of installing additional devices is that no external power source can be used to maintain the insulation, as the pantograph is subject to a high voltage of 25 kV. The conventional device therefore maintains the insulation using a high-capacity battery and simultaneously supplies power to the test device.

[0006] The space available for installing a high-capacity battery on the pantograph is limited, and the battery size is also limited to avoid compromising the aerodynamic properties of the rail vehicle. Since the inspection system consumes a lot of power, for example, for wireless external communication, the battery replacement cycle is very short, at just a few months.

[0007] Changing the battery requires disconnecting the high-voltage power line, and requiring workers to work on the vehicle's roof, which results in high costs and increases the risk of accidents. Solar or wind power has been proposed to boost battery power, but while these extend battery life, they do not solve fundamental problems associated with battery replacement.

[0008] Due to the frequent need to change batteries, the test devices can only be used on individual vehicles and not on all vehicles in operation for safety and maintenance reasons.

[0009] DE 10 2015 117 075 A1 discloses a current collector with a contact strip having a contact surface that can be brought into current-transmitting contact with the contact wire transversely to the path of the contact wire. A sensor arrangement for determining the position of the contact wire relative to the contact strip is possible. This sensor arrangement is firmly attached to the current collector and constantly determines a value that corresponds to the lateral position of the contact wire and / or at least a vertical position of the contact wire relative to the sensor arrangement. The object is to further develop a current collector in a practical manner and to provide a sensor arrangement with which the condition of the contact strip of a current collector can be determined.

[0010] DE 10 2014 200 032 A1 discloses a device for supplying a sensor with energy. The device comprises a storage capacitor for storing energy, wherein the storage capacitor can be coupled to a power supply device and is configured to supply the sensor with energy. Furthermore, the device comprises a switching device for coupling the storage capacitor to the power supply device and decoupling the storage capacitor from the power supply device.Additionally, the device comprises a control device coupled to the switching device and configured to control the energy supply to the sensor. The control device is configured to determine a current charge state of the storage capacitor and, if the current charge state falls below a first threshold, to send a first control signal to the switching device to couple the storage capacitor to the energy supply device. If the current charge state exceeds a second threshold, to send a second control signal to the switching device to decouple the storage capacitor from the energy supply device. This enables operation of the sensor over a very wide range of possible energy inputs without high power dissipation in the device.Furthermore, a sensor with such a device and a method for supplying the sensor with energy are proposed. Detailed explanation of the inventionTechnical task

[0011] The present invention was developed to solve the above-mentioned problems. Its goal is to equip a pantograph with the following units: a testing unit that checks the status of the pantograph in real time, a power supply unit that supplies power to the testing unit, and a harvester unit that collects energy from the electromagnetic field generated by the electricity supplied to the pantograph and transmits it to the power supply unit. A rechargeable battery in the power supply unit is continuously charged, thus requiring battery replacement only at the end of its service life, which reduces maintenance costs. The significant extension of the rechargeable battery replacement cycle also reduces the risk of work-related accidents. Means for problem solving

[0012] The present invention solves the problems mentioned:

[0013] A pantograph mounted on a rail vehicle comprises the following three units: a test unit that checks the condition of the pantograph, a power supply unit that supplies power to the test unit, and a harvester unit mounted on the pantograph that collects electrical energy from the pantograph and transmits it to the power supply unit.

[0014] The harvester unit comprises a magnetic field harvester mounted on a busbar of the pantograph, the harvester being provided externally around the busbar and comprising a core and a coil wound on the core.

[0015] The coil can be characterized by one half being wound on an upper and a lower section of the core.

[0016] The power supply unit is equipped with a core stabilization circuit to reduce core saturation. This circuit comprises a resistor connected in parallel with the output of the magnetic field harvester, a first switch connected in series with the resistor, and a second switch connected in series with the output of the magnetic field harvester.

[0017] In addition, the magnetic field harvester may include a multi-tap for respective sections of the coil, which controls the turns ratio of the coil, and a capacitor connected to both ends of the coil to compensate for a magnetizing inductance of the coil.

[0018] The multiple tap may be characterized in that it is designed with a plurality of selection switches which are switched according to the control of a control device in order to select any one of the taps which is connected to a respective section of the coil.

[0019] The harvester unit may also include a harvester for the electromagnetic field generated during use of the pantograph. This field harvester comprises a plate-shaped conductor section between a contact strip of the pantograph and the roof of the rail vehicle.

[0020] The power supply unit may comprise a power converter for rectifying a current collected by the harvester unit and a converter for converting the current rectified by the power converter into a voltage corresponding to the test unit.

[0021] The power supply unit may be equipped with a rechargeable battery to store the current rectified by the power converter. Effects of the invention

[0022] The present invention, in its above-described embodiment, comprises a testing unit that checks the status of the pantograph in real time, a power supply unit that supplies power to the testing unit, and a harvester unit mounted on the pantograph that collects the power and transmits it to the power supply unit, where a rechargeable battery is charged and used. This battery does not need to be replaced until its service life is exhausted, thus reducing maintenance costs. The significant extension of the rechargeable battery replacement cycle also reduces the risk of accidents during manual work. Description of the characters Fig. 1 is a conceptual diagram of a current collector testing apparatus according to the present invention. Fig. 2 is a block diagram of a pantograph testing apparatus according to the present invention. Fig.3 is a conceptual diagram of an electric field harvester of a current collector testing apparatus according to the present invention. Fig. 4 is a conceptual diagram of a magnetic field harvester of a current collector testing apparatus according to the present invention. Fig. 5 is a display screen of a meter showing an output voltage of a current collector test apparatus according to the present invention when the core is saturated. Fig. 6 is a graph showing a change in output voltage depending on a load resistance of the harvester in a current collector testing apparatus according to the present invention. Fig. 7 is a conceptual diagram of a magnetic field harvester of a current collector testing apparatus according to another embodiment of the present invention. Fig. 8 is an equivalent circuit diagram of the magnetic field harvester according to the embodiment of Fig. 7. Fig. 9 is a simplified equivalent circuit diagram of the magnetic field harvester according to the embodiment of Fig. 7. Fig. 10 is a circuit diagram showing the structure of the magnetic field harvester according to the embodiment of the Fig. 7 when used for performance simulation. Fig. 11 and Fig. 14 are diagrams showing a performance simulation of the magnetic field harvester according to the embodiment of the Fig. 7 illustrate. Fig. 15 is a simplified equivalent circuit diagram of the magnetic field harvester according to the embodiment of Fig. 7. Fig. Figure 16 is a diagram of a conventional magnetic field coupler for harvesting. Fig. 17 is an equivalent circuit diagram of the magnetic field coupler for harvesting the Fig. 16. Fig.18 is an example view illustrating current collection by an electric field harvester of a current collector testing apparatus according to the present invention. Fig. 19 is an equivalent circuit diagram of the example view of the Fig. 18. Fig. 20 is an example view in which the equivalent circuit of Fig. 19 a power supply unit and an electrical load are added. Fig. 21 is a state diagram showing one end of a bus bar of a current collector testing apparatus according to the present invention. Best mode for carrying out the invention

[0023] Preferred embodiments of the present invention will be explained in detail below with reference to the accompanying drawings. Like reference numerals are used throughout the drawings to refer to like components, and a repeated description of such like components is omitted. It is understood that the present invention may be implemented in many different forms and is not limited to the described embodiments.

[0024] The present invention is a testing device for a current collector. As described in Fig. 1 and Fig.21, the embodiment comprises a testing unit (400) mounted on a pantograph (330) of a rail vehicle, which checks the condition of the pantograph (330), furthermore an energy supply unit (600) which supplies the testing unit (400) with energy, and a harvester unit (500) arranged on the pantograph (330), which collects energy from the pantograph (330) and supplies it to the energy supply unit (600).

[0025] Here, as in Fig. 1, the test unit (400) and the power supply unit (600) are installed in a common housing. Alternatively, although not in Fig. 1, depending on the circumstances, may be installed in separate housings.

[0026] The pantograph (330) transmits power to the rail vehicle by bringing contact strips (332) into contact with an overhead line (340). It is insulated from the roof of the rail vehicle (310) by support insulators (320) provided in a lower region. The test unit (400) comprises a communication module (402) that receives measured values ​​from sensors (410) arranged on various parts of the pantograph (330) and transmits them to a remote server (700), as well as a microcontroller (MCU) (404) that controls the respective components.

[0027] The sensors (410) detect the status of the pantograph (330). For the purpose of obtaining information, the sensors (410) may include an acceleration sensor for detecting a possible impact of the pantograph (330), a GPS sensor for determining the geographical location of the rail vehicle, an infrared camera and a flash module for capturing an image in the event of a collision, and a gyro sensor connected to the contact strips of the pantograph (330). They operate using the power provided by the power supply unit (600).

[0028] As explained, the sensors (410) comprise several devices. The acceleration sensor and the gyro sensor for detecting a possible impact, as in Fig.1, can be arranged under the contact strips (332). The GPS sensor, the infrared camera, and the like are mounted in a housing at a suitable location depending on the characteristics of the respective device.

[0029] Since the present invention uses the harvester unit (500) to collect electrical energy from a magnetic field and, optionally, additionally from an electric field of the current collector (330) powered via the line (340), and the testing unit (400) is powered by the power supply unit (600), separate batteries are not required, and maintenance costs can be reduced. Furthermore, work-related accidents that can occur when manually replacing discharged batteries are prevented.

[0030] The harvester unit (500) includes a magnetic field harvester (100) that collects energy from the magnetic field of the current collector (330) and may additionally include an electric field harvester (510) that collects energy from the electric field of the current collector (330). It can thus harvest energy from both types of fields.

[0031] As in Fig. 1, the magnetic field harvester (100) is mounted on a conductor rail (L) that transmits the current collected by the contact strips (332) of the current collector (330) to a main circuit breaker and a main transformer of the rail vehicle. As shown in Fig. 4, the magnetic field harvester (100) comprises a core (110) arranged externally around the busbar (L) and a coil (120) wound on the core (110).

[0032] The magnetic field harvester (100) is attached to the busbar (L) by a separate clamping device. When current flows through the busbar (L), the magnetic field harvester (100) collects magnetic energy and supplies it to the power supply unit (600).

[0033] The coil (120) is wound halfway onto an upper and halfway onto a lower part of the core (110), so that the two sides remain unwound.

[0034] As in Fig. As shown in Figure 21, the end of the busbar (L) is formed by compressing a round tube so that the left and right sides are larger than the diameter of the busbar (L). When attaching the magnetic field harvester (100) to the busbar (L), the end should be inserted into the part not wound by the coil (120) to facilitate insertion.

[0035] The design of the coil (120) and core (110), in which the coil is wound only on the upper and lower parts of the core (110), minimizes the inner diameter of the core (110), thereby reducing its magnetic path length. This creates a stronger magnetic field within the core (110), enabling high-yield harvesting.

[0036] The power supply unit (600) converts and stores the energy received from the harvester unit (500) and supplies it to the testing unit (400). The power supply unit (600) comprises a rectifier (610) for rectifying the current supplied by the harvester unit (500), a converter (630) for converting it to a voltage corresponding to the testing unit (400), and an MCU (660) for controlling the individual components.

[0037] In the case of the magnetic field harvester (100), unlike the constant current of the electric field harvester (510), the current flow varies depending on the rail vehicle load, resulting in fluctuating energy yield. This requires rechargeable batteries to store remaining energy and provide backup power in times of insufficient energy supply.

[0038] Accordingly, the power supply unit (600) connected to the magnetic field harvester (100) comprises a rechargeable battery (640) that stores current rectified by the rectifier (610) and a charging device (650) for controlling the charging of the battery.

[0039] As a further embodiment of the present invention, the magnetic field harvester (100) may additionally be designed with a supercapacitor (620) which is arranged between the rechargeable battery (640) and the rectifier (610) and serves as a buffer.

[0040] The power supply unit (600) also includes a core stabilization circuit (670) to reduce the saturation of the core (110). As shown in Figure 1, the maximum output voltage of the magnetic field harvester (100) is very high when the core (110) is saturated due to the occurrence of a hysteresis loop. Therefore, the circuit of the power supply unit must be stabilized by reducing the saturation of the core (110).

[0041] As in Fig. As shown in Figure 5, the magnetic field harvester (100) has the property of changing sinusoidal waves into a pulsed waveform at a higher load resistance. Especially when the output terminal is open (charge-off state), the core is easily saturated at low primary current. Therefore, upon power-up, the circuit may be at risk due to the high charge.

[0042] However, if current is introduced by connecting a resistor to the output of the magnetic field harvester (100), the saturation level in the core (110) decreases, so that the voltage waveform changes to a sinusoidal shape and the maximum voltage is reduced.

[0043] Accordingly, the core stabilization circuit (670) contains, as shown in Fig. 4, a resistor (672) arranged in parallel with the output of the magnetic field harvester (100), a first switch (674) connected in series with the resistor (672) and a second switch (676) connected in series with the output of the magnetic field harvester (100).

[0044] As in Fig.As shown in Figure 4, the current supplied by the magnetic field harvester (100) can be interrupted when the rechargeable battery (640) is fully charged or not in charge by operating the first switch (674) and the second switch (676). For charging, the output of the magnetic field harvester (100) can be connected to the power supply unit (600) by reopening the first switch (674) and closing the second switch (676).

[0045] The resistor (672) connected to the first switch (674) is a device for stabilizing the core (100) when charging by the power supply unit (600) begins. When the second switch (676) is open and the first switch (674) is closed, it allows current to flow into the resistor (672) for a short time (0.1-0.5 seconds) to reduce the saturation level of the magnetic flux of the core (110).

[0046] Once the saturation level of the core (110) is reduced, the second switch (676) is closed and the output of the magnetic field harvester (100) is connected to the rectifier (610). The first switch (674) is then opened to prevent unnecessary energy consumption of the resistor (672).

[0047] Such a process can be described as shown in Table 1 below.

[71] [Table 1] Operating status first switch second switch Initial maneuvers open open Start of charging to open after 500 ms to to after 500 ms open to End of charging process to to after 100 ms to open after 100 ms open open

[0048] The charging method of the power supply unit (600) is configured to maximize energy yield. Since the magnetic field harvester (100) collects maximum energy at the point (voltage) where the core (110) begins to saturate, the MCU (660) of the power supply unit (600) detects the output voltage of the magnetic field harvester (100) to find the charging current that maximizes power. The MPTT (Maximum Power Point Tracking) protocol can be used as the control method.

[0049] When the design of the core (110) and coil (120) of the magnetic field harvester (100) is determined, the output voltage at saturation of the core (110) is also determined. Therefore, a voltage regulator that keeps the output voltage of the magnetic field harvester (100) constant can be used as an option.

[0050] Since the optimal voltage value varies depending on the capacity and configuration of the magnetic field harvester (100) (cross-sectional area of ​​the core (110), number of turns), it can only be used if the optimal voltage value is known.

[0051] As in Fig.7 as a further embodiment of the present invention, the magnetic field harvester (100) comprises the core (110) arranged externally on the busbar (L), the coil (120) wound on the core (110), a multi-tap (130) provided with a plurality of selection switches (SW) under the control of a control unit (140), by means of which each of a plurality of taps (131) on a respective section of the coil (120) can be controlled, and a capacitor (150) which is connected in parallel to both ends of the coil (120) and compensates the magnetizing inductance of the coil (120).

[0052] The turns ratio of the coil (120) is set according to an on / off signal of the selection switch (SW) of the multi-tap (130) and according to a switching signal of the control unit (140).

[0053] The multi-tap (130) comprises a plurality of selector switches (SW) individually connected to the taps (131). When a specific selector switch (e.g., SW2) is turned on according to a switching signal from the control unit (140), the remaining selector switches (e.g., SW1, SW3) turn off; depending on the connection of the specific selector switch (e.g., SW2), power is supplied to the power supply unit (600), which in turn supplies power to the test unit (400).

[0054] More specifically, the present invention is constructed such that the multi-tap (130) for adjusting the turns ratio of the coil is connected to the control unit (140) in a form including the core (110) and the coil (120).

[0055] The present invention is directed to transmitting maximum power by placing the capacitor (150) at both ends of the coil (120) to compensate for the magnetizing inductance of the coil.

[0056] As in Fig. 16 and Fig. As shown in Figure 17, a coil (3) is wound around a magnetic core (2), which in turn encloses a power line (1). This supplies power to a power conversion device (4) connected to a load.

[0057] In a conventional magnetic field coupler, the current ratio is selected to achieve the desired current and power. The area of ​​the core (2), the air gap, etc., are adjusted as shown in the following equation (1) so that the maximum magnetic flux density does not exceed the saturation magnetic flux of the selected core (2). Bmax=Lmlm / NAc

[0058] Here, L mthe magnetizing inductance, I m the current flowing through the magnetizing inductance and A c the cross-sectional area of ​​the core.

[0059] Based on the maximum input current I in , which can flow on the primary side when constructing a magnetic field coupler, the maximum magnetic flux density B max , the area and magnetizing inductance L m of the core (2).

[0060] In the Fig. 2 shown conventional magnetic field coupler is the one connected to the load R L supplied power P calculated from the equivalent circuit L as follows: PL=12w2Lm2RL2+w2Lm2lm2RLN2

[0061] However, since the capacitor (150) is provided in the present invention as described above, in the case of compensation of the capacitor (150) in the above equation (2), the term of the magnetizing inductance Lm eliminated and higher power can be transmitted.

[0062] The present invention enables the coupler (100) to operate actively by setting the desired tap (131) in the control unit (140) using the plurality of switches (SW).

[0063] In the present invention, the secondary coil (120) can be arranged as shown in the equivalent circuit diagram of the Fig.8, can be divided into two partial coils. The number of turns N1 of the secondary coil (120) changes, as the tap (131) is selectively connected according to the control of the selector switch (SW) by the control unit (140). This structure is characterized by the division of the secondary coil (120). On closer inspection, the secondary coil (120) resembles an autotransformer that divides and uses a single coil. In fact, the current flowing to the secondary side is converted again, just like in an autotransformer, and passed on to the load. A simplified equivalent circuit diagram for this can be found in Fig. 9.

[0064] The capacitor (150) ( =1(w2LmN2), Resonance condition applied) of the Fig. 8 compensates the value of the magnetizing inductance L mon the secondary side, so that LC can be eliminated accordingly, and the current flowing to the secondary side is converted in proportion to the number of turns N1 of the coil (120). After that, the partial coils on the secondary side run as transformers, as in Fig. 9 shown.

[0065] Fig. Figure 12 shows a circuit configuration for performance simulation of the present invention. The simulation compares the models according to the conventional and proposed design, as well as the simplified proposed design. In the proposed design, the magnetizing inductance L m entered within the transformer part.

[0066] The simulation results are in Fig. 11 and Fig.14. N is the total number of turns of the coil (120) on the secondary side, and N1 is the number of turns of the secondary coil (120), which varies depending on the selection of the selector switches (SW) and the taps (131) via the control unit (140).

[0067] Fig. Figure 11 shows a simulation diagram for the case where N=100 and N1=30. The red line shows the conventional structure, the blue line the structure proposed by the present invention, and the green line the waveform of the simplified structure. In addition, (a) is the load voltage and (b) is a diagram of the load current. Under the same conditions, Fig. 12 a simulation diagram for the case N=100, N1=50, Fig. 13 is a simulation diagram for the case N=100, N1=70, and Fig. 14 stands for the case N=100, N1=99.

[0068] The simulation results show that the current delivered to the load is much higher in the structure proposed by the present invention than in the conventional structure. Furthermore, the structure proposed by the present invention and the simplified equivalent structure exhibit the same characteristics in the idle state after a certain period of time, despite initially having a different shape. This is due to the fact that the actual structure contains capacitors and inductors, which means a time constant exists and a certain amount of time must pass to reach the idle state.

[0069] When a tap (131) is selected by operating the selection switch (SW) on the control unit (140) to adjust the number of turns N1 of the secondary coil (120), it becomes apparent that the lower the number of turns N1, the higher the collected current. This is because the primary current is transferred to the secondary side in the ratio N / N1, and larger amounts of current can only be transferred when the number of turns N1 of the secondary coil (120) is low. The proposed structure of the present invention therefore works according to the principle of taking a portion of the main current flowing through the busbar (L) and amplifying it as desired. In this way, more current can be transferred to the secondary side. Even when the current of the busbar (L) is low, a large current can be obtained by regulating the number of turns N1 of the secondary coil (120).

[0070] The equivalent circuit of the Fig. 9 can be simplified as in Fig. 15. Current corresponding to the value obtained by dividing the input current at the busbar (L) by the number of turns N1 of the secondary coil (120) is supplied to the power converter and the load R L According to this model, even using a conventional transformer with one tap (131), the shape described above can be derived by appropriately adjusting the number of turns N1 of the secondary coil (120), but in practice it is difficult to obtain an ideal shape, as in Fig. 15 to the conventional method. The reason for this is, as shown in Fig. 2, even if the magnetizing inductance L m compensating capacitor is connected, the value of the magnetizing inductance L also changes when the number of turns N1 of the coil is adjusted. m. Accordingly, the capacitor must be readjusted to adjust the magnetizing inductance L m to eliminate.

[0071] Even if a conventional general magnetic coupler is equipped with control unit (140) and selection switches (SW) as shown in Fig. 7 of the present invention, there is therefore the difficulty that an additional capacitor (150) must be installed for each selection switch (SW).

[0072] In contrast, the method proposed in the present invention with a capacitor (150) compensates the magnetizing inductance L m of the entire coil, so that even when changing the number of turns N1 of the secondary coil (120) the ideal shape as in Fig. 15 can be obtained.

[0073] Furthermore, in the conventional method, when the number of turns of the secondary coil (120) is reduced when the main current from the bus bar (L) is low, the current only flows into the coil for the selected number of turns. This physically weakens the bus bar (L) and the magnetic field coupling during the coupling period, and there is a possibility that the power transmission efficiency will decrease significantly with increasing leakage inductance. Also, the low magnetizing inductance requires a very large compensation capacitance, which makes the system more complex and difficult to implement. In contrast, with the present invention, even when the main current in the bus bar (L) is low, the current flows through the entire secondary coil (120) and is converted in a 1:N ratio, even if the value of the number of turns N1 of the secondary coil (120) is set low.Due to the split coil, it is converted back into high current on the secondary side and therefore does not pose a problem.

[0074] In relation to Fig. 7, the control unit (140) of the present invention monitors the power supplied to the load (170) and, if the power is insufficient, increases the number of turns N1 of the secondary coil (120) so that the active supply of stable power is ensured even when the current in the busbar (L) changes.

[0075] Since the primary current in a rail vehicle is subject to a very large fluctuation range, the turns ratio is regulated in the event of an unexpected amount of current, thus enabling the control of the voltage magnitude generated by the harvester unit (500).

[0076] For example, at a lower primary current, the circuit of the power supply unit (600) will not operate properly due to the low voltage of the harvester unit (500). In this case, the number of turns of the coil is increased to obtain a higher output voltage even at a low primary current. If the primary current is high, the turns ratio is adjusted to reduce the output voltage. This allows an appropriate output voltage to be obtained.

[0077] If no charging is taking place, the output voltage can be reduced to protect the circuit.

[0078] As in Fig. As shown in Figure 3, the electric field harvester (510) collects electrical energy from an electric field formed in the current collector (330). It is located between the contact strips (320) of the current collector (330) and the roof (310) of the rail vehicle and comprises a plate-shaped conductor component.

[0079] This means that the electric field harvester (510) uses a current collector (330) and the overhead line (340), which has a high potential difference to the vehicle roof.

[0080] An additional conductor (conductor component) electrically insulated from the pantograph (330) and the roof (310) of the rail vehicle may be considered. This conductor has a higher electrical potential the closer it is to the pantograph (330, high voltage) and a lower electrical potential the farther it is from the pantograph (330).

[0081] Here, the distance between the pantograph (330) and the roof (310) of the rail vehicle is small (approximately 40 cm or less), which means the electric field is very strong. At a short distance between the conductor and the pantograph (330), a large electric potential difference is generated with the pantograph (330), and electrical energy can easily accumulate in the conductor.

[0082] As described above, the current flowing in the current collector (330) generates an electric field around the current collector. The electric field harvester (510) includes a plate-shaped conductor (not shown) that generates current in response to the electric field, and a transformer (not shown) that regulates the voltage ratio of the conductor.

[0083] Therefore, the harvester unit (500) can draw power from the magnetic field created around the current collector (330) and supply the test unit (400) without a separate energy source.

[0084] Considering the process for collecting current by the electric field harvester (510) as described in Fig.As shown in Figure 18, the efficiency can be increased by balancing the capacitance formed in the electric field energy. If a conductor (circuit board) is present in the electric field harvester (510) in the upper area of ​​the rail vehicle, the capacitances C2-1, C2-2, and C3 are generated in addition to the existing capacitances (C1-1, C1-2).

[0085] Where C1-1 is the capacitance between the overhead line and the roof of the vehicle, C1-2 is the capacitance between the pantograph (330) and the roof (310) of the rail vehicle, and C2-1 is the capacitance between the plate-shaped conductor component (circuit board) and the pantograph (330). C2-2 is the capacitance between the wire (340) and the plate-shaped conductor component (circuit board), and C3 is the capacitance between the plate-shaped conductor component (circuit board) and the roof (310) of the vehicle.

[0086] The equivalent circuit diagram corresponds to that in Fig.19. Vs represents the voltage of the overhead line (340) - generally 25 kV RMS is present on the AC line. The parallel-arranged C1-1, C1-2 and C2-1, C2-2 can each be represented by a capacitance C1 or C2. The power supply unit (600) and the load (C L , R L ), which receives the supplied current, can be used according to the circuit of the Fig. 20 are shown.

[0087] The transformer (TF) contained in the power supply unit (600) serves to reduce the voltage of the electrical energy collected in the plate-shaped conductor component (circuit board) to the required level, and the rectifier contained in the power supply unit (600) can convert the transformer output into direct current. The transformer can be located in the power supply unit (600) or, as described above, in the electric field harvester (510).

[0088] The amount of energy absorbed in the conductor component is determined by the voltage applied to the transformer. First, the voltage of 25 kV is divided by C2, the parallel impedance of the transformer, and C3. If the equivalent impedance of the primary or secondary side of the transformer is defined as Z TF considered, the following relationship applies: ZTFa=C2‖ZTF=ZTFjwC2ZTF+1 ZTF=ZTFa−j1ωC3+ZTFaVS=ωZTFaC3VSωZTF(C2+C3)−j

[0089] V TF is the voltage supplied to the transformer, and it can be seen that V TF the larger the C3 is. In addition, the current (I S ) by V S initially divided into I1 and I3, where I3 is determined by the impedance of C1 and the equivalent impedance on the left side of the dashed line a.

[0090] C3 is connected in series with C2 and the transformer, so that regardless of the impedance of the transformer, no high current can flow if the impedance value of C3 (=1jwC3) is high. Therefore, the impedance value of C3 should be low and the value of C3 itself should be high.

[0091] Finally, the current flowing through the transformer (I TF ) is reduced by the current flowing from I3 to I2. If the value of C2 is very small, the impedance increases and most of the current flows through I TF . There, as in Fig. 18, the circuit board and the current collector (330) are arranged horizontally and do not face each other, the capacitance corresponding to C2 is not large.

[0092] Therefore, the power delivered to the transformer increases as the value of C3 increases. C3 refers to the capacitance between the circuit board and the roof of the vehicle. To achieve a large value of C3, the surface area of ​​the circuit board can be increased or a structure can be used that can improve the capacitance.

[0093] In another embodiment of the present invention, not shown in the drawings, the power supply unit (600) is mounted on the upper side of the rail vehicle and is exposed to the outside, so that the overall temperature decreases in winter temperatures. The rechargeable battery (640) contained in the power supply unit (600) performs poorly as the temperature drops. Therefore, a heating foil (not shown) is provided for the rechargeable battery (640). When the outside temperature drops below a predetermined temperature, it turns on to keep the temperature of the rechargeable battery (640) above a certain point and maintain its performance.

Claims

[1] Test device comprising: a testing unit (400) mounted on a pantograph (330) of a rail vehicle for inspecting the condition of the pantograph (330), a power supply unit (600) which supplies the test unit (400) with power, and a harvester unit (500) provided on the current collector (330), which collects electrical energy from the current collector (330) and supplies it to the power supply unit (600); wherein the harvester unit (500) comprises a magnetic field harvester (100) mounted on a busbar (L) of the current collector (330) with a core (110) provided outside the busbar (L) and a coil (120) wound on the core (110); and wherein the power supply unit (600) is designed with a core stabilization circuit (670) to reduce saturation of the core (110), wherein the core stabilization circuit (670) comprises a resistor (672) provided in parallel with the output of the magnetic field harvester (100), a first switch (674) connected in series with the resistor (672), and a second switch (676) connected in series with the output of the magnetic field harvester (100). [2] Testing device according to claim 1, wherein the coil (120) is wound halfway on an upper and a lower part of the core (110). [3] The testing apparatus according to claim 1, wherein the magnetic field harvester (100) comprises: a multiple tap (130) connected to respective portions of the coil (120) and controlling the turns ratio of the coil (120) by a controller (140), and a capacitor (150) connected in parallel to both ends of the coil (120) for compensating a magnetizing inductance of the coil (120). [4] Testing device according to claim 3, wherein the multiple tap (130) is designed with a plurality of selection switches (SW) which are switched by means of a control device (140) so that one of a plurality of taps (131) is selected which is connected to a respective section of the coil (120). [5] Testing device according to claim 1, wherein the harvester unit (500) comprises an electric field harvester (510) which uses an electric field formed in the current collector (330) and is attached to a plate-shaped conductor section between contact strips (320) of the current collector (330) and a roof (310) of the rail vehicle. [6] The testing apparatus according to claim 1, wherein the power supply unit (600) comprises a rectifier (610) for rectifying a current generated by the harvester unit (500) and a converter (630) for converting the current rectified by the rectifier (610) into a voltage corresponding to the testing unit (400). [7] Testing device according to claim 6, wherein the power supply unit (600) is designed with a rechargeable battery (640) which stores the current rectified by the rectifier (610).

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