Method for reducing metro running rail power supply backflow generated stray current

Abstract

The present application relates to and is suitable for the track return current power supply system of the metro train with direct current power supply, the scheme in the application provides a method for reducing the stray current generated by the metro running rail power return current, a connection branch formed by parallel inductance, super capacitor, IGBT switch, contactor and the like is adopted, and the conduction and flow direction of the intelligent control current is used to effectively filter the harmonic components of the return current, which can effectively reduce the leakage of the stray current harmonic components generated by the harmonic of the inverter switch circuit of the train to the outside of the running track itself, and prevent the electrochemical corrosion from harming other facilities and equipment.

Description

TECHNICAL FIELD

[0001] The present application relates to and is suitable for the power supply system of track return current of metro train powered by direct current, the scheme in the application can effectively reduce the leakage of stray current harmonic components generated by the harmonic of the inverter switch circuit of the train to the outside of the running track itself, and cause electrochemical corrosion to harm other facilities and equipment. BACKGROUND

[0002] See Figure 1 ;

[0003] The prior art is to reduce the amount of stray current, including: reducing the running track rail potential, strengthening the insulation of the direct current power supply device and the running track to the ground, setting up a stray current collection net, layer-by-layer shielding, using the first path of stray current (i.e. the structure of the track bed steel) to form the first shielding net to prevent the leakage of stray current to the outside of the track bed; connecting the tunnel structure steel to form the second shielding net to prevent the leakage of stray current to the outside of the tunnel, and harm other facilities, but these measures still cannot well solve the problem of stray current leakage.

[0004] The current situation of metro stray current hazards in major cities around the world is: the buried metal pipelines around the metro, the outer skin of communication cables, and the steel bars in the main structure of the station and the interval tunnel, even the steel bars in the foundation of the surrounding high-rise buildings, cause electrochemical corrosion. This electrochemical corrosion not only shortens the service life of metal pipelines, but also reduces the strength and durability of the main structure of the metro steel reinforced concrete, and even causes disastrous accidents, which is a common problem of metro in the world.

[0005] Facing the built and opened line and the new line under construction, the realistic stray current corrosion hazard condition cannot be changed, there is no measure for the filter of the running rail itself which is the source of the stray current, the current analysis theory is analyzed from the concept of pure direct current, but the inverter of the train is the switching circuit composed of IGBT, the fundamental wave of the train just starting is close to the sine wave, there is asynchronous modulation to synchronous modulation and high number rectangular wave instead of sine wave in the synchronous modulation, finally a square wave instead of half sine wave, these transition points also appear abnormal oscillation convergence process, so the three same moment cannot be balanced, the actual measurement is also so. Therefore, the leakage stray current is composed of two components of direct current and alternating current, the running rail with tens of kilometers forms a large capacitor with the busbar and the steel structure net of the track bed. The track is the positive electrode, and the ground is the negative electrode, even if the insulation is done well, due to the small spacing caused by the strength requirement of the track bed structure steel corresponding to the support track, I(stray current) = V(track) ω C, for the harmonic component, the C value is large and it is also close to the short circuit to the ground, and after the stray current is transmitted to the next shielding net, it is still a harmonic component, still forms the leakage of the external transmission, which is an important reason for the uncontrollable leakage of the stray current. The peak value of the return current of the commonly used 6-vehicle train can reach 3000 amperes, the stray current accounts for only a small part, but the absolute value is still not small, and the harmonic component in the stray current is more harmful. After the train runs, the track is heated, or the factors such as humidity (water evaporation), the pure resistance of the track and the track foundation will increase and the direct current component of the stray current will decrease, but the alternating current component of the stray current will not change.

[0006] The existing effective solution is to use the third rail return current, and the current return current does not flow through the running rail, but the cost is very high, and more importantly, the built track line cannot be modified at all. SUMMARY

[0007] In view of the defects in the prior art, the purpose of the present application is to first filter the running rail itself, which can effectively reduce the harmonic component of the track return current from the source, thereby reducing the leakage of the stray current.

[0008] In order to achieve the above purpose, the technical method adopted by the present application is:

[0009] The application relates to a method for reducing the stray current generated by the power return flow of a subway running rail, which adopts a filtering method for the harmonic components of the return flow of the running rail itself as the source of the stray current, and in the state of keeping the physical steel rail of the running rail unchanged, a parallel connection branch of an inductor, a super capacitor, an IGBT switch and a contactor is adopted, the super capacitor is discharged by controlling the IGBT switch and the contactor, a forward current is formed to break the voltage parallel connection of the rail section, and the current is forced to pass through the parallel connection branch composed of the inductor, the super capacitor, the IGBT switch and the contactor, so that the harmonic components of the return flow are effectively filtered; in the state of keeping the physical steel rail of the running rail discontinuous, an insulating joint and an inductor are connected in parallel, and the harmonic components of the return flow are effectively filtered.

[0010] The application relates to a system for reducing the stray current generated by the power return flow of a subway running rail, which comprises a filtering connection unit 1, a filtering connection unit 2 and a filtering connection unit 3.

[0011] The filtering connection unit 1 is electrically connected to the rail waist of the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected in parallel with the running rail.

[0012] The first connection line 101 of the filtering connection unit 1 is connected to the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the power substation 8 through the running rail; the second connection line 102 of the filtering connection unit 1 is connected to the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the power substation 7 through the running rail, thereby forming a parallel connection branch.

[0013] The filtering connection unit 2 is electrically connected to the rail waist of the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected in parallel with the running rail.

[0014] The first connection line 201 of the filtering connection unit 2 is connected to the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the power substation 8 through the running rail; the second connection line 202 of the filtering connection unit 2 is connected to the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the power substation 7 through the running rail, thereby forming a parallel connection branch.

[0015] The filtering connection unit 3 is electrically connected to the rail waist of the running rail at the moment when the train 5 accelerates to the uniform speed state, and is connected in parallel with the running rail.

[0016] The first connection line 301 of the filter connection unit 3 is connected with the running rail at the moment when the train 5 finishes accelerating and enters the uniform speed state, and is connected to the negative terminal of the substation 8 through the running rail; the second connection line 302 of the filter connection unit 3 is connected with the running rail at the moment when the train 5 finishes accelerating and enters the uniform speed state, and is connected to the negative terminal of the substation 7 through the running rail, thereby forming a parallel branch.

[0017] The filter connection unit 1, the filter connection unit 2 and the filter connection unit 3 are each connected with the running rail, and are independent operation devices and are not connected with each other.

[0018] The method for reducing the generation of stray current of the power supply return current of the running rail of the subway according to the present application includes four actual operation technical solutions for filtering the return current of the running rail, i.e., the technical solution one, the technical solution two, the technical solution three and the technical solution four of the present application, which can be selected and applied according to actual conditions.

[0019] The technical solution one of the present application is as follows:

[0020] The technical solution one of the present application includes the filter connection unit 1 of the technical solution one (see Fig. 3(a)), the filter connection unit 2 of the technical solution one (see Fig. 4(a)) and the filter connection unit 3 of the technical solution one (see Fig. 5(a)).

[0021] The filter connection unit 1 of the technical solution one includes a first connection line 101 of the running rail, an inductor L 111 , a super capacitor C 111 , a contactor normally open contact KM 111 , a contactor normally closed contact KM 112 , a contactor normally open contact KM 113 , a contactor normally closed contact KM 114 , a bidirectional conduction IGBT switch Q 111 , and a second connection line 102 of the running rail, wherein the second connection line 102 of the running rail contains a parallel section resistance R 111 , an inductor L 111 and a super capacitor C 111 in series resistance R 112 .

[0022] The first connection line 101 of the running rail is welded to the 103 end of the inductor L 111 at the rail waist, the 104 end of the inductor L 111 is connected to the 105 end of the contactor normally open contact KM 111 , and is connected with the 106 end of the contactor normally closed contact KM 114 to form a parallel connection, the 107 end of the contactor normally open contact KM 111 is connected with the 108 end of the super capacitor C 111The positive terminal 108 is connected to the contactor normally closed contact KM 112 The terminal 109 is connected to the contactor normally closed contact KM 114 The terminal 111 is connected to the super capacitor C 111 The negative terminal 112 is connected to the contactor normally open contact KM 113 The terminal 113 is connected to the contactor normally closed contact KM 112 The terminal 110 is connected to the bidirectional conduction IGBT switch Q 111 The terminal 115 is connected to the contactor normally open contact KM 113 The terminal 114 is connected to the contactor normally open contact KM 111 The terminal 116 is connected to the track second connection line 102.

[0023] On the basis of the above scheme, the track itself between the track first connection line 101 and the track second connection line 102 is physically unchanged in overall continuity, including the track parallel section internal resistance R 111 The track first connection line 101 is connected to one end of the track parallel section internal resistance R 111 The track second connection line 102 is connected to the other end of the track parallel section internal resistance R 111 ;

[0024] The welding connection of the track first connection line 101 and the track second connection line 102 to the track is brazing;

[0025] On the basis of the above scheme, the inductance L 111 The function is to block the harmonic components of the backflow, the super capacitor C 111 The function is to store energy and discharge, the contactor normally open contact KM 111 , the contactor normally closed contact KM 112 , the contactor normally open contact KM 113 , the contactor normally closed contact KM 114 The function is to adjust the current direction flowing through the super capacitor C 111 The inductance L 111 And the super capacitor C 111 Are in series, including the total internal resistance R 112 The bidirectional conduction IGBT switch Q 111 Has intelligent control ability, which is controlled by a control chip, and the function is to control the positive and negative direction of the current, and to protect the super capacitor C 111 When storing energy and discharging, the possible overvoltage and overcurrent are adjusted and protected, and the unit as a whole is connected by a small amount of cable.

[0026] The filter connection unit 2 of the scheme one includes: the track first connection line 201, the inductance L 121 , the super capacitor C121 , contactor normally open contact KM 121 , contactor normally closed contact KM 122 , contactor normally open contact KM 123 , contactor normally closed contact KM 124 , bidirectional conducting IGBT switch Q 121 , the end of the running rail second connecting line 202, which contains the running rail parallel section resistance R 121 , inductor L 121 and super capacitor C 121 series resistance R 121 ;

[0027] Wherein, the end of the running rail first connecting line 201 is welded at the running rail waist to connect the 203 end of the inductor L 121 , the 204 end of the inductor L 121 connects the 205 end of the contactor normally open contact KM 121 , and connects the 206 end of the contactor normally closed contact KM 124 to form a parallel connection, the 207 end of the contactor normally open contact KM 121 connects the positive end 208 of the super capacitor C 121 , and connects the 209 end of the contactor normally closed contact KM 122 , the 211 end of the contactor normally closed contact KM 124 connects the negative end 212 of the super capacitor C 121 , and connects the 213 end of the contactor normally open contact KM 123 , the 210 end of the contactor normally closed contact KM 122 connects the 215 end of the bidirectional conducting IGBT switch Q 121 , and connects the 214 end of the contactor normally open contact KM 123 to form a parallel connection, the 216 end of the bidirectional conducting IGBT switch Q 121 connects the end of the running rail second connecting line 202;

[0028] On the basis of the above scheme, the running rail itself between the end of the running rail first connecting line 201 and the end of the running rail second connecting line 202 remains physically overall continuous, containing the running rail parallel section resistance R 121 , the end of the running rail first connecting line 201 is connected to one end of the running rail parallel section resistance R 121 , and the end of the running rail second connecting line 202 is connected to the other end of the running rail parallel section resistance R 121 ;

[0029] The welding connection of the running rail first connecting line 201 and the running rail second connecting line 202 to the running rail is brazing;

[0030] On the basis of the above scheme, the inductor L121 The function of the super capacitor C 121 is to store energy and discharge, the contactor normally open contact KM 121 , the contactor normally closed contact KM 122 , the contactor normally open contact KM 123 , the contactor normally closed contact KM 124 The function of the super capacitor C 121 is to adjust the current direction flowing through the inductor L 121 and the super capacitor C 121 is in series, containing the total internal resistance R 122 , the bidirectional conduction IGBT switch Q 121 has intelligent control capability, which is controlled by the control chip, and the function is to control the positive and negative direction of the current, and the super capacitor C 121 may be overvoltage and overcurrent during energy storage and discharge, and the unit is connected by a small amount of cable.

[0031] The filter connection unit 3 of the first scheme includes: the first connection line 301 end of the running rail, the inductor L 131 , the super capacitor C 131 , the bidirectional conduction IGBT switch Q 131 , and the second connection line 302 end of the running rail, which contains the running rail parallel section internal resistance R 131 , the inductor L 131 and the super capacitor C 131 are connected in series with the internal resistance R 132 ;

[0032] Wherein, the first connection line 301 end of the running rail is welded at the running rail waist to connect the 303 end of the inductor L 131 , the 304 end of the inductor L 131 connects the negative electrode end 305 of the super capacitor C 131 , and the positive electrode end 306 of the super capacitor C 131 connects the 307 end of the bidirectional conduction IGBT switch Q 131 , and the 308 end of the bidirectional conduction IGBT switch Q 131 connects the second connection line 302 end of the running rail.

[0033] On the basis of the above scheme, the running rail itself between the first connection line 301 end and the second connection line 302 end of the running rail remains physically overall continuous, containing the running rail parallel section internal resistance R 131 , the first connection line 301 end of the running rail is connected with one end of the running rail parallel section internal resistance R 131 , and the second connection line 302 end of the running rail is connected with the other end of the running rail parallel section internal resistance R 131 ;

[0034] The welding connection of the first connection line 301 end and the second connection line 302 end of the running rail with the running rail is brazing connection.

[0035] The function of the inductor L 13 1 is to block the harmonic components of the backflow, and the super capacitor C 131 The function of the inductor L 131 and the super capacitor C 131 is to store energy and discharge, and the inductor L 132 and the super capacitor C 131 are connected in series and contain a total internal resistance R 131 , a bidirectional conduction IGBT switch Q 211 has intelligent control capability and is controlled by a control chip, and the function is to control the positive and negative direction of the current, and the super capacitor C 211 may be adjusted and protected during energy storage and discharge, and the unit is connected by a small amount of cable.

[0036] The technical solution two of the application comprises:

[0037] The technical solution two of the application comprises:

[0038] See Figure 6(a);

[0039] The first filter connection unit 1 of the second scheme comprises a first connection line 101 end of the running rail, an insulating joint J 211 , an inductor L 211 , and a second connection line 102 end of the running rail, wherein the inductor L 211 contains an internal resistance R 211 ;

[0040] The first connection line 101 end of the running rail is connected to the 119 end of the inductor L 211 through welding at the waist of the running rail, and is connected to the 117 end of the insulating joint J 211 , the 120 end of the inductor L 211 is connected to the second connection line 102 end of the running rail, and the second connection line 102 end of the running rail is connected to the 118 end of the insulating joint J 211 ;

[0041] On the basis of the above scheme, the insulating joint J 211 is connected to the non-physical steel rail continuous place of the running rail, that is, the 117 end of the insulating joint J 211 is conductively disconnected between the 118 end of the insulating joint J 211 , and the current loop between the first connection line 101 end of the running rail and the second connection line 102 end of the running rail is blocked;

[0042] The welding connection of the first connection line 101 end and the second connection line 102 end of the running rail with the running rail is brazing connection.

[0043] In the above scheme, the function of the inductor L 211 is to block the harmonic components of the backflow, and the unit is connected as a whole by a small amount of cable.

[0044] The filter connection unit 2 of the second scheme includes a running rail first connection line 201 end, an insulating joint J 221 , an inductor L 221 , and a running rail second connection line 202 end, wherein the internal resistance R 221 of the inductor L 221 is contained;

[0045] The 219 end of the inductor L 221 is connected to the 217 end of the insulating joint J 221 by welding at the running rail waist, and the 220 end of the inductor L 221 is connected to the 202 end of the running rail second connection line, while the 202 end of the running rail second connection line is connected to the 218 end of the insulating joint J 221 ;

[0046] In the above scheme, the insulating joint J 221 is connected at a non-physical steel rail continuous position of the running rail, that is, the 217 end of the insulating joint J 221 is conductively disconnected from the 218 end of the insulating joint J 221 , thereby blocking the current loop between the 201 end of the running rail first connection line and the 202 end of the running rail second connection line;

[0047] The welding connection of the 201 end of the running rail first connection line and the 202 end of the running rail second connection line to the running rail is brazing;

[0048] In the above scheme, the function of the inductor L 221 is to block the harmonic components of the backflow, and the unit is connected as a whole by a small amount of cable.

[0049] The filter connection unit 3 of the second scheme includes a running rail first connection line 301 end, an insulating joint J 231 , an inductor L 231 , and a running rail second connection line 302 end, wherein the internal resistance R 231 of the inductor L 231 is contained;

[0050] The 311 end of the inductor L 231 is connected to the 309 end of the insulating joint J 231 by welding at the running rail waist, and the 220 end of the inductor L 231The 312 end of the inductor L is connected to the second connection line 302 of the running rail, and the second connection line 302 of the running rail is connected to the insulation joint J 231 The 310 end of the inductor L is connected to the insulation joint J

[0051] On the basis of the above scheme, the insulation joint J 231 Accesses the non-physical steel rail continuous place of the running rail, that is, the insulation joint J 231 The 309 end of the inductor L is connected to the insulation joint J 231 The 310 end of the inductor L is connected to the insulation joint J

[0052] The welding connection of the first connection line 301 of the running rail and the second connection line 302 of the running rail to the running rail is brazing connection;

[0053] On the basis of the above scheme, the inductor L 231 The function is to block the harmonic component of the return current, and the unit is connected by a small amount of cable.

[0054] Technical scheme three of the application:

[0055] The technical scheme three of the application includes: the filtering connection unit 1 of scheme three, the filtering connection unit 2 of scheme three, and the filtering connection unit 3 of scheme three.

[0056] See FIG. 7(a);

[0057] The filtering connection unit 1 of scheme three includes: the first connection line 101 of the running rail, the inductor L 311 , the second connection line 102 of the running rail, which contains the internal resistance R 311 of the parallel section of the running rail, and the internal resistance R312 of the inductor L 311 ;

[0058] The 121 end of the inductor L 311 is connected to the first connection line 101 of the running rail through welding at the rail waist, and the 122 end of the inductor L 311 is connected to the second connection line 102 of the running rail;

[0059] On the basis of the above scheme, the running rail itself between the first connection line 101 of the running rail and the second connection line 102 of the running rail remains physically overall continuous, contains the internal resistance R 311 of the parallel section of the running rail, the first connection line 101 of the running rail is connected to one end of the internal resistance R 311 of the parallel section of the running rail, and the second connection line 102 of the running rail is connected to the other end of the internal resistance R 311 of the parallel section of the running rail;

[0060] The welding connection between the two ends of the first connection line 101 and the second connection line 102 of the running rail and the running rail is brazing connection.

[0061] On the basis of the above scheme, the function of the inductor L 311 is to block the harmonic components of the backflow, and the unit is connected as a whole by a small amount of cable.

[0062] The filtering connection unit 2 of the third scheme includes: the first connection line 201 of the running rail, the inductor L 321 , the second connection line 202 of the running rail, which contains the internal resistance R 321 of the parallel section of the running rail and the internal resistance R 321 of the inductor L 322 ;

[0063] The first connection line 201 of the running rail is connected to the 221 end of the inductor L 321 through welding at the waist of the running rail, and the 222 end of the inductor L 321 is connected to the second connection line 202 of the running rail.

[0064] On the basis of the above scheme, the running rail itself between the first connection line 201 of the running rail and the second connection line 202 of the running rail remains physically overall continuous, containing the internal resistance R 321 of the parallel section of the running rail, the first connection line 201 of the running rail is connected to one end of the internal resistance R 321 of the parallel section of the running rail, and the second connection line 202 of the running rail is connected to the other end of the internal resistance R 321 of the parallel section of the running rail.

[0065] The welding connection between the two ends of the first connection line 201 of the running rail and the second connection line 202 of the running rail and the running rail is brazing connection.

[0066] On the basis of the above scheme, the function of the inductor L 321 is to block the harmonic components of the backflow, and the unit is connected as a whole by a small amount of cable.

[0067] The filtering connection unit 3 of the third scheme includes: the first connection line 301 of the running rail, the inductor L 331 , the second connection line 302 of the running rail, which contains the internal resistance R 331 of the parallel section of the running rail and the internal resistance R 331 of the inductor L 332 ;

[0068] The first connection line 301 of the running rail is connected to the 313 end of the inductor L 331 through welding at the waist of the running rail, and the 314 end of the inductor L 331 is connected to the second connection line 302 of the running rail.

[0069] On the basis of the above scheme, the walking rail itself between the walking rail first connecting line 301 end and the walking rail second connecting line 302 end remains physically overall continuous unchanged, containing the walking rail parallel section internal resistance R 331 , the walking rail first connecting line 301 end is connected with one end of the walking rail parallel section internal resistance R 331 , and the walking rail second connecting line 302 end is connected with the other end of the walking rail parallel section internal resistance R 331 .

[0070] The welding connection of the walking rail first connecting line 301 end and the walking rail second connecting line 302 end with the walking rail is brazing connection.

[0071] On the basis of the above scheme, the function of the inductance L 331 is to block the harmonic components of the return current, and the unit is overall connected by a small amount of cable.

[0072] The fourth technical scheme of the application

[0073] The fourth technical scheme of the application is based on the first technical scheme of the application and combined with the third technical scheme of the application.

[0074] See Figure 8 .

[0075] The filter connection unit 1 of the first scheme still consists of the walking rail first connecting line 101 end, the walking rail second connecting line 102 end, and the walking rail welding connection to form the first parallel branch, the filter connection unit 1 of the third scheme is placed in the periphery of the filter connection unit 1 of the first scheme, and the walking rail third connecting line 141 end, the walking rail fourth connecting line 142 end, and the walking rail welding connection are connected, a bidirectional conducting IGBT switch Q 411 is added between the inductance L 411 (including internal resistance R 413 ) and the walking rail fourth connecting line 142 end, to form the second parallel branch.

[0076] Among them, the walking rail third connecting line 141 end is connected with the 143 end of the inductance L 411 , the 144 end of the inductance L 411 is connected with the 145 end of the bidirectional conducting IGBT switch Q 411 , and the 146 end of the bidirectional conducting IGBT switch Q 411 is connected with the walking rail fourth connecting line 142 end.

[0077] The welding connection of the walking rail third connecting line 141 end and the walking rail fourth connecting line 142 end with the walking rail is brazing connection.

[0078] On the basis of the above scheme, the third connecting line 141 of the running rail and the end of the fourth connecting line 142 of the running rail still physically maintain the overall continuity of the running rail unchanged, including the internal resistance R 411 of the running rail parallel section 412 ;

[0079] On the basis of the above scheme, the bidirectional conduction IGBT switch Q 421 has intelligent control ability, which is controlled by a control chip, and the function is to control the switch to be disconnected when the super capacitor C 111 in the filter connection unit 1 of scheme one is charged, so that the capacitor C 111 is charged under the voltage formed by the internal resistance R 111 of the running rail parallel section.

[0080] The filter connection unit 2 of the above scheme is still composed of the first parallel branch of the first connecting line 201 of the running rail, the second connecting line 202 of the running rail and the welding connection of the running rail. The filter connection unit 2 of scheme three is placed in the periphery of the filter connection unit 2 of scheme one, and the third connecting line 241 of the running rail and the fourth connecting line 242 of the running rail are welded and connected. The bidirectional conduction IGBT switch Q 421 (including internal resistance R 423 ) is added between the inductor L 421 and the fourth connecting line 242 of the running rail, to form a second parallel branch.

[0081] Among them, the third connecting line 241 of the running rail is connected to the 243 end of the inductor L 421 , the 244 end of the inductor L 421 is connected to the 245 end of the bidirectional conduction IGBT switch Q 421 , and the 246 end of the bidirectional conduction IGBT switch Q 421 is connected to the fourth connecting line 242 of the running rail.

[0082] The welding connection of the third connecting line 241 of the running rail and the fourth connecting line 242 of the running rail with the running rail is brazing.

[0083] On the basis of the above scheme, the third connecting line 241 of the running rail and the fourth connecting line 242 of the running rail still physically maintain the overall continuity of the running rail unchanged, including the internal resistance R 421 of the running rail parallel section 422 ;

[0084] On the basis of the above scheme, the bidirectional conduction IGBT switch Q 421 has intelligent control ability, which is controlled by a control chip, and the function is to control the switch to be disconnected when the super capacitor C 121Charging, control switch itself off, so that the capacitor C 121 In the walking rail parallel section resistance R 121 Charged under the voltage formed in the section.

[0085] The filter connection unit 3 of the first scheme still consists of the first parallel branch of the walking rail first connection line 301 end, the walking rail second connection line 302 end and the walking rail welding connection. The filter connection unit 3 of the third scheme is placed in the periphery of the filter connection unit 3 of the first scheme, and is connected by the walking rail third connection line 341 end, the walking rail fourth connection line 342 end and the walking rail welding connection. The inductor L 431 (Containing resistance R 433 ) and the walking rail fourth connection line 342 end between the bidirectional conduction IGBT switch Q 431 , to form a second parallel branch;

[0086] Among them, the walking rail third connection line 341 end is connected with the 343 end of the inductor L 431 , the 344 end of the inductor L 431 is connected with the 345 end of the bidirectional conduction IGBT switch Q 431 , and the 346 end of the bidirectional conduction IGBT switch Q 431 is connected with the walking rail fourth connection line 342 end;

[0087] The welding connection of the walking rail third connection line 341 end and the walking rail fourth connection line 342 end with the walking rail is brazing;

[0088] On the basis of the above scheme, the walking rail third connection line 341 end and the walking rail fourth connection line 342 end still maintain the overall continuity of the walking rail in physics, containing the walking rail parallel section resistance R 431 , the walking rail parallel section resistance R 432 ;

[0089] On the basis of the above scheme, the bidirectional conduction IGBT switch Q 431 has intelligent control ability, which is controlled by a control chip. The function is that when the super capacitor C 131 in the filter connection unit 3 of the first scheme is charged, the control switch is turned off, so that the capacitor C 131 is charged under the voltage formed in the walking rail parallel section resistance R 131 .

[0090] Advantages:

[0091] The application is the first to use and implement filtering method on the running track itself of the backflow of the stray current source in the world rail transit industry, which can greatly prolong the service life of the steel reinforcement of the subway structure, the surrounding buried metal pipeline, the outer skin of the communication cable, and even the steel reinforcement in the cement foundation of the surrounding building group, thereby improving their safety and reliability, and having huge economic and social effects and a world-wide popular market. The technical scheme one, the technical scheme three and the technical scheme four of the application can maintain the status quo of the existing physical continuous track, do not require any modification for the running line, and greatly reduce the use cost.

[0092] When the train starts, the overhead line supplies power to the train, and the train outputs backflow through the running track by the wheel pair. Since the train is moving, the backflow output end of the train traction current through the wheel is also moving. The train is within the range of the filtering connection unit 1, the filtering connection unit 2 and the filtering connection unit 3 from the static state to the acceleration section. The application uses a filtering measure on the running track itself to reduce the harmonic component of the stray current, so that the harmonic component of the backflow output by the train during the whole acceleration process is filtered. The harmonic component of the stray current is reduced to a minimum outside the range of the filtering connection unit 1 to the filtering connection unit 3. The filtering connection unit 2 is arranged to reduce the influence of the stray current formed by the backflow harmonic component when the train enters the synchronous modulation on the station. BRIEF DESCRIPTION OF DRAWINGS

[0093] The application has the following drawings:

[0094] Figure 1 It is a structural schematic diagram of the existing anti-stray current technical scheme.

[0095] Fig. 2(a) is a system structure schematic diagram of the method for reducing the stray current generated by the backflow of the power supply of the subway running track.

[0096] Fig. 2(b) is a schematic diagram of the application when the train enters the station electric brake.

[0097] Fig. 2(c) is a schematic diagram of the application when the train starts to run.

[0098] Fig. 2(d) is a schematic diagram of the application before the train accelerates and enters the uniform speed state.

[0099] Fig. 3(a) is a filtering connection unit 1 structure schematic diagram of the technical scheme one of the application.

[0100] Fig. 3(b) is a current flow direction diagram of the filtering connection unit 1 of the technical scheme one of the application when the switch is turned on during the train enters the station electric brake.

[0101] Fig. 3(c) is a current flow direction diagram of the filtering connection unit 1 of the technical scheme one of the application when the switch is turned on during the train starts to run until the train accelerates and enters the uniform speed state.

[0102] Fig. 4(a) is a structural schematic diagram of the filter connection unit 2 of the technical solution one of the present application.

[0103] Fig. 4(b) is a current flow direction diagram of the filter connection unit 2 of the technical solution one of the present application when the train is electrically braked in the station.

[0104] Fig. 4(c) is a current flow direction diagram of the filter connection unit 2 of the technical solution one of the present application when the train is started to run.

[0105] Fig. 4(d) is a current flow direction diagram of the filter connection unit 2 of the technical solution one of the present application when the train is accelerated and before entering the uniform speed state.

[0106] Fig. 5(a) is a structural schematic diagram of the filter connection unit 3 of the technical solution one of the present application.

[0107] Fig. 5(b) is a current flow direction diagram of the filter connection unit 3 of the technical solution one of the present application when the train is electrically braked in the station.

[0108] Fig. 5(c) is a current flow direction diagram of the filter connection unit 3 of the technical solution one of the present application when the train is started to run until the train is accelerated and enters the uniform speed state.

[0109] Fig. 6(a) is a structural schematic diagram of the unit of the technical solution two of the present application.

[0110] Fig. 6(b) is a current flow direction diagram of all the connection units of the technical solution two of the present application when the train is started to run.

[0111] Fig. 6(c) is a current flow direction diagram of all the connection units of the technical solution two of the present application when the train is accelerated and before entering the uniform speed state.

[0112] Fig. 7(a) is a structural schematic diagram of the connection unit of the technical solution three of the present application.

[0113] Fig. 7(b) is a current flow direction diagram of all the connection units of the technical solution three of the present application when the train is started to run. Fig. 7(c) is a current flow direction diagram of all the connection units of the technical solution three of the present application when the train is accelerated and before entering the uniform speed state.

[0114] Figure 8 Fig. 8(a) is a structural schematic diagram of the connection unit of the technical solution four of the present application. DETAILED DESCRIPTION

[0115] In order to more specifically describe the present application, the technical solutions of the present application are described in more detail below in combination with the drawings and the specific embodiments. It is emphasized here that the following description is only exemplary and is not intended to limit the scope and application of the present application.

[0116] The application adopts and implements a filtering method for the backflow harmonic component of the running rail itself as a stray current source, in a state of keeping the physical steel rail of the running rail unchanged, a parallel inductor, super capacitor, IGBT switch and contactor connection branch are adopted, through the control of the IGBT switch and the contactor contact, the super capacitor is discharged to form a voltage blocking parallel rail segment forward conduction, and the current is forced to pass through the parallel branch composed of the inductor, super capacitor, IGBT switch and contactor, so that the harmonic component of the backflow is effectively filtered; in a state of keeping the physical steel rail of the running rail discontinuous, an insulating joint and a parallel inductor are adopted to effectively filter the harmonic component of the backflow.

[0117] Fig. 2(a) is a schematic diagram of the system structure of the method for reducing the stray current generated by the backflow of the metro running rail power supply, which comprises: a filtering connection unit 1, a filtering connection unit 2 and a filtering connection unit 3.

[0118] The filtering connection unit 1 is electrically connected to the rail waist of the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected in parallel with the running rail.

[0119] The first running rail connecting line 101 of the filtering connection unit 1 is connected to the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the substation 8 through the running rail; the second running rail connecting line 102 of the filtering connection unit 1 is connected to the running rail at the tail end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the substation 7 through the running rail, thereby forming a parallel branch.

[0120] The filtering connection unit 2 is electrically connected to the rail waist of the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected in parallel with the running rail.

[0121] The first running rail connecting line 201 of the filtering connection unit 2 is connected to the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the substation 8 through the running rail; the second running rail connecting line 202 of the filtering connection unit 2 is connected to the running rail at the head end of the train 5 when the train 5 stops at the station platform, and is connected to the negative end of the substation 7 through the running rail, thereby forming a parallel branch.

[0122] The filtering connection unit 3 is electrically connected to the rail waist of the running rail at the moment when the train 5 accelerates to the uniform speed state, and is connected in parallel with the running rail.

[0123] The first connection line 301 of the filter connection unit 3 is connected with the track at the moment when the train 5 finishes accelerating and enters the uniform speed state, and is connected to the negative terminal of the substation 8 through the track; the second connection line 302 of the filter connection unit 3 is connected with the track at the moment when the train 5 finishes accelerating and enters the uniform speed state, and is connected to the negative terminal of the substation 7 through the track, thus forming a parallel branch.

[0124] As shown in Fig. 2(a), the filter connection unit 1, the filter connection unit 2 and the filter connection unit 3 are each connected with the track and are independent operating devices, and are not connected with each other;

[0125] When the train starts, the overhead line system 4 supplies power to the train 5 as shown in Fig. 2(a), and the train 5 outputs the backflow to the track through the wheels 6. Since the train is moving, the backflow output end of the train 5 through the wheels 6 is also moving. The train is within the range of the filter connection unit 1, the filter connection unit 2 and the filter connection unit 3 from the stationary state to the acceleration stage. The present application uses the technology of taking filter measures on the track itself to reduce the harmonic components of the stray current, so that the harmonic components of the backflow output by the train 5 during the whole acceleration process are filtered. The harmonic components of the stray current outside the range of the filter connection unit 1 to the filter connection unit 3 are reduced to the minimum. The filter connection unit 2 is arranged to reduce the influence of the stray current formed by the harmonic components of the backflow when the train enters the synchronous modulation on the station;

[0126] Fig. 2(b) shows the schematic diagram of the present application when the train enters the station and the electric brake. When the train 5 enters the station and the electric brake, the traction motor is in the state of the generator. At this time, the current I 11 flows from the negative terminal of the substation 7 to the wheels 6 of the train through the track. This current is not formed by the switching circuit, and the harmonic is minimal, so the filter method is not used. The current I 11 flows through the filter connection unit 3, the filter connection unit 2 and the filter connection unit 1 of the present application and then enters the train 5 through the wheels 6;

[0127] Fig. 2(c) shows the schematic diagram of the present application when the train starts and runs. When the train 5 starts and runs and leaves the station platform, the traction motor is in the state of the electric motor. At this time, the backflow I 12 is output by the train 5 through the wheels 6, and flows to the negative terminal of the substation 7 through the track. After flowing through the filter connection unit 2 and the filter connection unit 3 of the present application, the backflow I 13 is output by the train 5 through the wheels 6, and flows to the negative terminal of the substation 7 through the track. After flowing through the filter connection unit 2 and the filter connection unit 3 of the present application, the backflow I

[0128] Figure 2(d) shows a schematic diagram of the present application before acceleration and entering a uniform state. When before acceleration and entering a uniform state, the position is approaching the filter connection unit 3 of the present application, at this time the backflow I 12 Output by the train 5 through the wheel 6, through the running rail to the negative terminal of the substation 7, after flowing through the filter connection unit 3 of the present application to the negative terminal of the substation 7, the backflow I 13 Output by the train 5 through the wheel 6, through the running rail to the negative terminal of the substation 8, after flowing through the filter connection unit 2 and the filter connection unit 1 of the present application to the negative terminal of the substation 8.

[0129] Technical solution one of the present application:

[0130] As shown in Figure 2(a), the technical solution one of the present application includes: the filter connection unit 1 of solution one, the filter connection unit 2 of solution one, the filter connection unit 3 of solution one;

[0131] As shown in Figure 3(a), the filter connection unit 1 of solution one includes: the first running rail connection line 101 end, the inductor L 111 , the super capacitor C 111 , the contactor normally open contact KM 111 , the contactor normally closed contact KM 112 , the contactor normally open contact KM 113 , the contactor normally closed contact KM 114 , the bidirectional conduction IGBT switch Q 111 , the second running rail connection line 102 end, which contains the running rail parallel section internal resistance R 111 , the inductor L 111 and the super capacitor C 111 series internal resistance R 112 ;

[0132] Wherein, the first running rail connection line 101 end is welded at the running rail waist to connect the 103 end of the inductor L 111 , the 104 end of the inductor L 111 connects the 105 end of the contactor normally open contact KM 111 , and connects the 106 end of the contactor normally closed contact KM 114 to form a parallel connection, the 107 end of the contactor normally open contact KM 111 connects the positive end 108 of the super capacitor C 111 , and then connects the 109 end of the contactor normally closed contact KM 112 , the 111 end of the contactor normally closed contact KM 114 connects the negative end 112 of the super capacitor C 111 , and then connects the 113 end of the contactor normally open contact KM 113 , the 109 end of the contactor normally closed contact KM 112the 110 end of the contactor is connected to the 115 end of the bidirectional IGBT switch Q 111 and the normally open contact KM 113 of the contactor is connected to the 114 end of the bidirectional IGBT switch Q 111 to form a parallel connection, and the 116 end of the contactor is connected to the end of the second connection line 102 of the running rail;

[0133] On the basis of the above scheme, the running rail itself between the end of the first connection line 101 of the running rail and the end of the second connection line 102 of the running rail remains physically overall continuous, and contains the parallel section internal resistance R 111 of the running rail, the end of the first connection line 101 of the running rail is connected to one end of the parallel section internal resistance R 111 of the running rail, and the end of the second connection line 102 of the running rail is connected to the other end of the parallel section internal resistance R 111 of the running rail;

[0134] The welding connection of the running rail at the end of the first connection line 101 of the running rail and the end of the second connection line 102 of the running rail is brazing;

[0135] On the basis of the above scheme, the inductor L 111 functions to block the harmonic components of the backflow, the super capacitor C 111 functions to store energy and discharge, the normally open contact KM 111 of the contactor, the normally closed contact KM 112 of the contactor, the normally open contact KM 113 of the contactor, the normally closed contact KM 114 of the contactor functions to adjust the current direction flowing through the super capacitor C 111 , the inductor L1 11 and the super capacitor C 111 are in series, containing the total internal resistance R 112 , the bidirectional IGBT switch Q 111 has intelligent control capability and is controlled by a control chip, and functions to control the positive and negative directions of the current flow, and to adjust and protect the possible overvoltage and overcurrent of the super capacitor C 111 when storing energy and discharging, and the unit as a whole is connected by a small amount of cable.

[0136] As shown in FIG. 4(a), the filter connection unit 2 of the scheme one includes: the end of the first connection line 201 of the running rail, the inductor L 121 , the super capacitor C 121 , the normally open contact KM 121 of the contactor, the normally closed contact KM 122 of the contactor, the normally open contact KM 123 of the contactor, the normally closed contact KM 124 of the contactor, and the bidirectional IGBT switch Q 121The second connecting line 202 of the running rail includes the internal resistance R of the parallel section of the running rail. 121 Inductor L 121 and supercapacitor C 121 Series internal resistance R 122 .

[0137] Among them, the first connecting line 201 of the running rail is welded to the web of the running rail and connected to the inductor L. 121 Terminal 203, inductor L 121 The 204 terminal is connected to the normally open contact KM of the contactor. 121 Terminal 205, and connected to the normally closed contact KM of the contactor. 124 The 206 terminals are connected in parallel, and the normally open contact of the contactor is KM. 121 Terminal 207 and supercapacitor C 121 The positive terminal 208 is connected, and then connected to the normally closed contact KM of the contactor. 122 Terminal 209 is connected, and the normally closed contact of the contactor is KM. 124 The 211 terminal and the supercapacitor C 121 The negative terminal 212 is connected, and then connected to the normally open contact KM of the contactor. 123 Terminal 213 is connected to the normally closed contact KM of the contactor. 122 The 210 terminal is connected to the bidirectional IGBT switch Q. 121 Connect to terminal 215 and to the normally open contact KM of the contactor. 123 The 214 terminals are connected in parallel, forming a bidirectional IGBT switch Q. 121 End 216 connects to end 202 of the second connecting line of the running rail;

[0138] Based on the above scheme, the running rail itself between the first connecting line 201 end and the second connecting line 202 end of the running rail remains physically continuous, including the internal resistance R of the parallel section of the running rail. 121 The internal resistance R of the first connecting line 201 end of the running rail and the parallel section of the running rail 121 One end is connected, and the second connecting line 202 of the running rail is connected in parallel with the running rail. The internal resistance R of the section is... 121 The other end is connected;

[0139] The welding connection between the first connecting line 201 end and the second connecting line 202 end of the running rail and the running rail is brazing.

[0140] Based on the above scheme, the inductor L 121 The function of the supercapacitor C is to block harmonic components from returning current. 121 The function is energy storage and discharge; the normally open contact of the contactor is KM. 121 Contactor normally closed contact KM 122 Normally open contact KM of the contactor 123The contactor normally closed contact KM 124 The function of the contactor normally closed contact KM 121 is to regulate the direction of the current flowing through the super capacitor C 121 , the inductor L 121 and the super capacitor C 122 are in series, containing the total internal resistance R 121 , the bidirectional conducting IGBT switch Q 121 has intelligent control capability, which is controlled by the control chip, and the function is to control the positive and negative direction of the current, and to regulate and protect the possible overvoltage and overcurrent of the super capacitor C 131 during energy storage and discharge, and the unit is connected by a small amount of cable.

[0141] As shown in Figure 5(a), the filter connection unit 3 of the first scheme includes: the running rail first connection line 301 end, the inductor L 131 , the super capacitor C 131 , the bidirectional conducting IGBT switch Q 131 , the running rail second connection line 302 end, which contains the running rail parallel section internal resistance R 131 , the inductor L 131 and the super capacitor C 132 in series internal resistance R .

[0142] Among them, the running rail first connection line 301 end is welded at the running rail waist to connect the 303 end of the inductor L 131 , the 304 end of the inductor L 131 connects the negative electrode end 305 of the super capacitor C 131 , the positive electrode end 306 of the super capacitor C 131 connects the 307 end of the bidirectional conducting IGBT switch Q 131 , and the 308 end of the bidirectional conducting IGBT switch Q 131 connects the running rail second connection line 302 end.

[0143] On the basis of the above scheme, the running rail itself between the running rail first connection line 301 end and the running rail second connection line 302 end remains physically overall continuous, containing the running rail parallel section internal resistance R 131 , the running rail first connection line 301 end and the one end of the running rail parallel section internal resistance R 131 are connected, and the running rail second connection line 302 end is connected with the other end of the running rail parallel section internal resistance R 131 .

[0144] The welding connection of the running rail first connection line 301 end and the running rail second connection line 302 end with the running rail is brazing;

[0145] On the basis of the above scheme, the function of the inductor L 131 is to block the harmonic components of the backflow, and the super capacitor C131 The function of the filter connection unit 1 is to store energy and discharge, and the inductor L 131 and the super capacitor C 131 are connected in series, and the total internal resistance R 132 is included. 131 The bidirectional IGBT switch Q 131 has intelligent control capability and is controlled by a control chip, and the function is to control the positive and negative directions of the current, and the super capacitor C 111 is charged and protected from overvoltage and overcurrent during energy storage and discharge, and the unit is connected by a small amount of cable.

[0146] Embodiment:

[0147] In the method for reducing the stray current generated by the power return flow of the metro running rail, the embodiment of the technical solution one of the application is:

[0148] Fig. 3(b) shows the current flow direction diagram of the switch conduction of the filter connection unit 1 of scheme one when the train 5 is station electric braking. When the train 5 is station electric braking as shown in Fig. 2(b), the bidirectional IGBT switch Q 111 in the filter connection unit 1 of scheme one is turned on, and the contactor normally closed contact KM 112 and the contactor normally closed contact KM 114 are turned on, the contactor normally open contact KM 111 and the contactor normally open contact KM 113 are turned off, the current I 11 is divided into the current I 111 flowing through the second running rail connecting line 102 end to the positive electrode of the super capacitor C 111 , and then the current I 111 flows from the negative electrode of the super capacitor C 111 through the inductor L 111 (including the internal resistance R 111 of the inductor L 112 and the super capacitor C 11 ) to the first running rail connecting line 101 end and returns to the current I 111 flowing to the wheel 6, and at the same time, the voltage formed at the internal resistance R 111 of the running rail parallel section charges the super capacitor C 111 , and after the charging is completed or when the train 5 reaches the filter connection unit 1 of scheme one, the bidirectional IGBT switch Q 111 is turned off.

[0149] Fig. 3(c) shows the current flow direction diagram of the switch conduction of the filter connection unit 1 of scheme one when the train starts running until the train accelerates to the constant speed state. When the train 5 starts running and accelerates away from the station platform as shown in Fig. 2(c) and Fig. 2(d), the bidirectional IGBT switch Q 111Contactor normally open contact KM 113 Conducting, contactor normally closed contact KM 112 Conducting, contactor normally closed contact KM 114 Disconnecting, super capacitor C fully charged 111 Discharging current I 130 Flowing through inductor L from positive terminal 111 , running rail first connecting line 101 end, running rail parallel section with internal resistance R 111 , running rail second connecting line 102 end to super capacitor C 111 Negative terminal forms a loop (including inductor L 111 and internal resistance R 111 of super capacitor C 112 ) and forms a voltage, blocking backflow I 13 Flowing to running rail parallel section with internal resistance R 111 , forcing backflow I 13 to flow through running rail second connecting line 102 end, super capacitor C 111 , inductor L 111 , running rail first connecting line 101 end parallel branch, inductor L 111 filters harmonic components of backflow I 13 , after which backflow I 13 flows to negative terminal of substation 8 at running rail first connecting line 101 end, and I 130 repeats the flow through the above parallel branch; when train 5 accelerates to a constant speed, bidirectional conducting IGBT switch Q 111 disconnects the circuit, and all contactor contacts in the unit reset.

[0150] Fig. 4(b) shows the current flow direction of the switch conducting of the filtering connection unit 2 of scheme one when the train enters the station electric braking. When train 5 enters the station electric braking as shown in Fig. 2(b), at this time, the bidirectional conducting IGBT switch Q 121 conducts the circuit of the filtering connection unit 2 of scheme one, at the same time, contactor normally closed contact KM 122 conducts, contactor normally closed contact KM 124 conducts, contactor normally open contact KM 121 conducts, contactor normally open contact KM 123 disconnects, current I 11 divides current I 112 flows through running rail second connecting line 202 end to super capacitor C 121 positive terminal, and then from super capacitor C 121 negative terminal through inductor L 121 (including inductor L 121 and internal resistance R 121 of super capacitor C 122 ) to running rail first connecting line 201 end and returns to current I11 The flow is directed towards wheel 6, while the resistance R within the parallel section of the running rail is... 121 Under the voltage formed at the location, for the supercapacitor C 121 Charging; once fully charged, the bidirectional IGBT switch Q is turned on. 121 Disconnect the circuit.

[0151] Figure 4(c) shows the current flow diagram of the switch in filter connection unit 2 of Scheme 1 during train startup. When train 5 starts and leaves the station platform as shown in Figure 2(c), the bidirectional IGBT switch Q in filter connection unit 2 of Scheme 1 is turned on. 121 The circuit is closed, and the normally closed contact KM of the contactor is activated. 122 Contactor normally closed contact KM 124 The normally open contact KM of the contactor is conducting. 121 Contactor normally open contact KM 123 Disconnect, supercapacitor C 121 Release current I 120 The flow originates from the positive end and passes through the second connecting line 202 of the running rail, including the internal resistance R. 121 Parallel section of the running rail, first connecting line 201 of the running rail, inductor L 121 Then to supercapacitor C 121 The negative terminal forms a circuit (which includes inductance L) 121 With supercapacitor C 121 internal resistance R 122 And generate voltage to block the return current I. 12 Flow to the internal resistance R 121 The parallel section of the running track forces the return flow I 12 The current flows through the first connecting line 201 of the running rail and the inductor L 121 Supercapacitor C 121 The parallel branch of the second connecting line 202 of the running rail is connected by inductor L. 121 For reflux I 12 The harmonic components are filtered, and then the return current I is applied. 12 The current flows from the second connecting line 202 of the running rail to the negative terminal of substation 7, while I 120 The train repeatedly flows through the aforementioned parallel branch; when train 5 accelerates to the position of filter connection unit 2 in Scheme 1, the bidirectional IGBT switch Q is turned on. 121 disconnect.

[0152] Figure 4(d) shows the current flow diagram of the switch in filter connection unit 2 of Scheme 1 before acceleration and entering a constant speed state. When train 5 starts and accelerates as shown in Figure 2(d) and passes the position of filter connection unit 2 of Scheme 1, the track return direction changes to the opposite direction shown in Figure 2(c). At this time, the normally open contact KM of the contactor in filter connection unit 2 of Scheme 1... 121 Contactor normally open contact KM123 The contactor is closed, and contactor KM is conducting. 122 Contactor normally closed contact KM 124 Disconnect, and after a very short time difference, the bidirectional IGBT switch Q is turned on. 121 Conducting circuit, supercapacitor C 121 Release current I 131 Flow from the positive terminal through inductor L 121 The first connecting line 201 of the running rail, including internal resistance R 121 The parallel section of the running rail, the second connecting line 202 of the running rail, and then to the supercapacitor C 121 The negative terminal forms a circuit (which includes inductance L) 121 With supercapacitor C 121 internal resistance R 122 And generate voltage to block the return current I. 13 Flow to the internal resistance R 121 The parallel section of the running track forces the return flow I 13 The flow passes through the second connecting line 202 of the running rail and the supercapacitor C. 121 Inductor L 121 The parallel branch of the first connecting line 201 of the traveling rail is connected by inductor L. 121 For reflux I 13 The harmonic components are filtered, and then the return current I is applied. 13 The current flows from the first connecting line 201 of the running rail to the negative terminal of substation 8, while I 131 The flow repeats through the above parallel branches; when train 5 finishes acceleration and enters a constant speed state, the bidirectional IGBT switch Q is activated. 121 Disconnect the circuit and reset all contactor contacts within the unit.

[0153] Figure 5(b) shows the current flow diagram of the filter connection unit 3 in Scheme 1 when the train is electrically braked upon entering the station. When train 5 is electrically braked upon entering the station as shown in Figure 2(b), the bidirectional IGBT switch Q in the filter connection unit 3 of Scheme 1 is activated. 131 When the circuit is open, the current I 11 Distributed current I 113 The flow goes through the second connecting line 302 of the running rail to the supercapacitor C 131 The positive end, then the supercapacitor C 131 Negative terminal through inductor L 131 (including inductance L) 131 With supercapacitor C 131 internal resistance R 132 After reaching the first connecting line 301 of the running rail, it returns to the current I. 11 The flow is directed towards wheel 6, while the resistance R within the parallel section of the running rail is... 131 Under the voltage formed at the location, for the supercapacitor C 131Charging, full charge, bidirectional conducting IGBT switch Q 131 Disconnecting circuit.

[0154] Fig. 5(c) shows the current flow direction of the filter connection unit 3 of the first scheme when the train starts running until the train accelerates to the constant speed state. When the train 5 starts to leave the station platform and accelerates as shown in Fig. 2(c), Fig. 2(d), the bidirectional conducting IGBT switch Q 131 Conducting circuit, super capacitor C fully charged 131 Releasing current I 121 From the positive end through the track second connection line 302 end, the track parallel section with internal resistance R 131 The track first connection line 301 end, the inductor L 131 To the super capacitor C 131 The negative end forms a loop (which contains the inductor L 131 And the internal resistance R 131 Of the super capacitor C 132 ) and forms a voltage, blocking the backflow I 12 Flowing to the track parallel section with internal resistance R 131 Forcing the backflow I 12 Through the parallel branch of the track first connection line 201 end, inductor L 121 , super capacitor C 121 Track second connection line 302 end, the inductor L 131 Filters the harmonic components of the backflow I 12 After which the backflow I 12 At the track second connection line 302 end flows to the negative end of the substation 7, and I 121 Repeats the flow through the above parallel branch; when the train 5 accelerates to the constant speed state, the bidirectional conducting IGBT switch Q 111 Disconnecting circuit.

[0155] The interval between subway trains is about two minutes or more, when the second train following the train 5 repeats the station electric braking as shown in Fig. 2(b), the filter connection unit 1 of the first scheme, the filter connection unit 2 of the first scheme, the filter connection unit 3 of the first scheme repeat the above charging process;

[0156] When the second train repeats the train 5 to start running and accelerate as shown in Fig. 2(c), Fig. 2(d), the filter connection unit 1 of the first scheme, the filter connection unit 2 of the first scheme, the filter connection unit 3 of the first scheme repeat the above filtering process.

[0157] Avoidance of resonance in the selection of inductance and super capacitor parameters;

[0158] The intelligent control chip controls all bidirectional conducting IGBT switches and all contactor contacts in all units, controls the change of super capacitor current direction, and protects the possible overvoltage and overcurrent.

[0159] When the inductance and super capacitor in any parallel branch of any unit fail, the bidirectional conducting IGBT switch of the unit immediately disconnects the circuit, and returns to the state before the application is used, without any influence on train operation.

[0160] The second technical solution of the application:

[0161] As shown in Fig. 6(a), the second technical solution of the application includes: the filter connection unit 1 of the second technical solution, the filter connection unit 2 of the second technical solution, and the filter connection unit 3 of the second technical solution.

[0162] As shown in Fig. 6(a), the filter connection unit 1 of the second technical solution includes: a running rail first connection line 101 end, an insulating joint J2 11, an inductance L 211 , and a running rail second connection line 102 end, wherein the inductance L 211 includes an internal resistance R 211 ;

[0163] The running rail first connection line 101 end is connected to the 119 end of the inductance L 211 through welding at the rail waist of the running rail, and is connected to the 117 end of the insulating joint J 211 ; the 120 end of the inductance L 211 is connected to the running rail second connection line 102 end, and the running rail second connection line 102 end is connected to the 118 end of the insulating joint J 211 ;

[0164] On the basis of the above-mentioned solution, the insulating joint J 211 is connected to the non-physical steel rail continuous place of the running rail, that is, the 117 end of the insulating joint J 211 is conductively disconnected from the 118 end of the insulating joint J 211 , so as to block the current loop between the running rail first connection line 101 end and the running rail second connection line 102 end.

[0165] The welding connection of the running rail first connection line 101 end and the running rail second connection line 102 end to the running rail is brazing;

[0166] On the basis of the above-mentioned solution, the function of the inductance L 211 is to block the harmonic components of the backflow, and the unit as a whole is connected by a small amount of cable.

[0167] As shown in Fig. 6(a), the filter connection unit 2 of the second technical solution includes: a running rail first connection line 201 end, an insulating joint J221 , inductance L 221 , the first connection line 201 end of the running rail, containing the internal resistance R 221 of the inductance L 221 ;

[0168] Wherein, the first connection line 201 end of the running rail is connected with the 219 end of the inductance L 221 through welding at the web of the running rail, and connected with the 217 end of the insulation joint J 221 , the 220 end of the inductance L 221 is connected with the second connection line 202 end of the running rail, while the second connection line 202 end of the running rail is connected with the 218 end of the insulation joint J 221 ;

[0169] On the basis of the above scheme, the insulation joint J 221 is connected at the non-physical continuous place of the running rail, that is, the 217 end of the insulation joint J 221 is conductively disconnected with the 218 end of the insulation joint J 221 , so as to block the current loop between the first connection line 201 end of the running rail and the second connection line 202 end of the running rail;

[0170] The welding connection of the first connection line 201 end of the running rail and the second connection line 202 end of the running rail with the running rail is brazing connection;

[0171] On the basis of the above scheme, the function of the inductance L 221 is to block the harmonic components of the return current, and the unit is connected by a small amount of cable.

[0172] As shown in Figure 6(a), the filtering connection unit 3 of the second scheme includes: the first connection line 301 end of the running rail, the insulation joint J 231 , the inductance L 231 , the second connection line 302 end of the running rail, containing the internal resistance R 231 of the inductance L 231 ;

[0173] Wherein, the first connection line 301 end of the running rail is connected with the 311 end of the inductance L 231 through welding at the web of the running rail, and connected with the 309 end of the insulation joint J 231 , the 312 end of the inductance L 231 is connected with the second connection line 302 end of the running rail, while the second connection line 302 end of the running rail is connected with the 310 end of the insulation joint J 231

[0174] On the basis of the above scheme, the insulation joint J 231 is connected at the non-physical continuous place of the running rail, that is, the 217 end of the insulation joint J 231 ​309 terminal and insulating connector J 231 Conductive isolation between the 310 terminals blocks the current loop between the first connecting line 301 and the second connecting line 302 of the running rail.

[0175] The welding connection between the first connecting line 301 end and the second connecting line 302 end of the running rail and the running rail is brazing.

[0176] Based on the above scheme, the inductor L 231 Its function is to block harmonic components of the return flow, and the unit is connected by a small number of cables.

[0177] Implementation method:

[0178] In the method for reducing the flow of power supply return current in subway running tracks, the second embodiment of the present invention is as follows:

[0179] According to the harmonic component of the return current = V·ω·C, the capacitance (C) at all insulating joints in the second technical solution of the present invention is extremely small, and the harmonic component flowing through the insulating point is also extremely small.

[0180] Figure 6(b) shows the current flow diagram of filter connection unit 1, filter connection unit 2, and filter connection unit 3 in Scheme 2 during train startup. When train 5 starts and leaves the station platform as shown in Figure 2(c), the return current I... 13 The return flow from wheel 6 to the running rail is directed to the negative terminal of substation 8. At this time, the insulating joint J of filter connection unit 1 in scheme two on the running rail... 211 For reflux I 13 Forming a barrier, the vast majority of I 13 The current flows through the second connecting line 102 of the running rail and the inductor L 211 (including its internal resistance R) 211 The parallel branch of the first connecting line 101 of the running rail then flows to the negative terminal of substation 8. This process is carried out by inductor L. 211 For reflux I 13 Filtering the harmonic components;

[0181] Reflow I 12 The return flow from wheel 6 to the running rail is directed to the negative terminal of substation 7. At this time, the insulated connector J of filter connection unit 2 in scheme two is located on the running rail. 221 For reflux I 12 Forming a barrier, the vast majority of I 12 The current flows through the first connecting line 201 of the running rail and the inductor L 221 (including its internal resistance R) 221 The parallel branch of the second connecting line 202 of the running rail then flows to the negative terminal of substation 7. This process is carried out by inductor L. 221The harmonic component of the return current I 12 is filtered; at this time, the filter connection unit 3 of scheme two insulates the joint J on the running rail 231 The return current I 12 is blocked, and most of the return current I 12 flows through the parallel branch of the end of the first connection line 301 of the running rail, the inductor L 231 (including the internal resistance R 231 ) of the end of the second connection line 302 of the running rail, and then flows to the negative terminal of the substation 7; this process is filtered by the inductor L 231 The harmonic component of the return current I 12 is filtered.

[0182] Figure 6(c) is a current flow diagram of the filter connection unit 1 of scheme two, the filter connection unit 2 of scheme two, and the filter connection unit 3 of scheme two before the train accelerates and enters a uniform speed state. When the train 5 starts and accelerates as shown in Figure 2(d) and passes the position of the filter connection unit 2 of scheme two, at this time, the filter connection unit 2 of scheme two insulates the joint J on the running rail 221 The return current I 13 is blocked, and most of the return current I 13 flows through the parallel branch of the end of the second connection line 202 of the running rail, the inductor L 221 (including the internal resistance R 221 ) of the end of the first connection line 201 of the running rail, and then flows to the negative terminal of the substation 8; this process is filtered by the inductor L 221 The harmonic component of the return current I 13 is filtered.

[0183] At this time, the filter mode of the filter connection unit 1 of scheme two and the filter connection unit 3 of scheme two remains unchanged as shown in Figure 6(b).

[0184] All units in the technical scheme two of the present application can use inductors with large inductance to improve the filtering effect.

[0185] In order to run the train smoothly without impact and ensure the comfort of the train, the existing track is a continuous track of physical steel rails, and the installation of insulation points will inevitably cause some impact, and the modification of the already operated line will bring a lot of workload, and the daily maintenance cost will increase.

[0186] The technical scheme three of the present application:

[0187] As shown in Figure 7(a), the technical scheme three of the present application includes: the filter connection unit 1 of scheme three, the filter connection unit 2 of scheme three, and the filter connection unit 3 of scheme three.

[0188] As shown in Figure 7(a), the filter connection unit 1 of scheme three includes: the end of the first connection line 101 of the running rail, the inductor L311 The second connecting line 102 of the running rail includes the internal resistance R of the parallel section of the running rail. 311 Inductor L 311 internal resistance R 312 ;

[0189] The first connecting line 101 of the running rail is connected to an inductor L by welding to the web of the running rail. 311 Terminal 121, inductor L 311 End 122 connects to end 102 of the second connecting line of the running rail;

[0190] Based on the above scheme, the running rail itself between the first connecting line 101 end and the second connecting line 102 end of the running rail remains physically continuous, including the internal resistance R of the parallel section of the running rail. 311 The internal resistance R of the first connecting line 101 end of the running rail and the parallel section of the running rail 311 One end is connected, and the second connecting line 102 of the running rail is connected in parallel with the running rail. The internal resistance R of the section is... 311 The other end is connected;

[0191] The welding connection between the first connecting line 101 end and the second connecting line 102 end of the running rail and the running rail is brazing.

[0192] Based on the above scheme, the inductor L 311 Its function is to block harmonic components of the return flow, and the unit is connected by a small number of cables.

[0193] As shown in Figure 7(a), the filter connection unit 2 of the third scheme includes: the first connection line 201 of the running track, and the inductor L. 321 The second connecting line 202 of the running rail includes the internal resistance R of the parallel section of the running rail. 321 Inductor L 321 internal resistance R 322 ;

[0194] The first connecting line 201 of the running rail is connected to an inductor L by welding to the web of the running rail. 321 Terminal 221, inductor L 321 End 222 connects to end 202 of the second connecting line of the running rail;

[0195] Based on the above scheme, the running rail itself between the first connecting line 201 end and the second connecting line 202 end of the running rail remains physically continuous, including the internal resistance R of the parallel section of the running rail. 321 The internal resistance R of the first connecting line 201 end of the running rail and the parallel section of the running rail 321 One end is connected, and the second connecting line 202 of the running rail is connected in parallel with the running rail. The internal resistance R of the section is... 321 The other end is connected;

[0196] The welding connection between the first connecting line 201 end and the second connecting line 202 end of the running rail and the running rail is brazing.

[0197] Based on the above scheme, the inductor L 321 Its function is to block harmonic components of the return flow, and the unit is connected by a small number of cables.

[0198] As shown in Figure 7(a), the filter connection unit 3 of the third scheme includes: the first connection line 301 end of the running track, and the inductor L. 331 The second connecting line 302 of the running rail includes the internal resistance R of the parallel section of the running rail. 331 Inductor L 331 internal resistance R 332 ;

[0199] The first connecting line 301 of the running rail is connected to an inductor L by welding it to the web of the running rail. 331 Terminal 313, inductor L 331 End 314 connects to end 302 of the second connecting line of the running rail;

[0200] Based on the above scheme, the running rail itself between the first connecting line 301 end and the second connecting line 302 end of the running rail remains physically continuous, including the internal resistance R of the parallel section of the running rail. 331 The internal resistance R of the first connecting line 301 end of the running rail and the parallel section of the running rail 331 One end is connected, and the second connecting line 302 of the running rail is connected in parallel with the running rail. The internal resistance R of the section is... 331 The other end is connected;

[0201] The welding connection between the first connecting line 301 end and the second connecting line 302 end of the running rail and the running rail is brazing.

[0202] Based on the above scheme, the inductor L 331 Its function is to block harmonic components of the return flow, and the unit is connected by a small number of cables.

[0203] Implementation method:

[0204] In the method for reducing the flow of power supply return current in subway running tracks, the third embodiment of the present invention is as follows:

[0205] Figure 7(b) shows the current flow diagram of filter connection unit 1, filter connection unit 2, and filter connection unit 3 in Scheme 3 during train startup. When train 5 starts and leaves the station platform as shown in Figure 2(c), the return current I... 13The return current from wheel 6 to the running rail flows to the negative terminal of substation 8. At this time, the filter connection unit 1 of scheme three has an inductor L connected in parallel on the physically continuous running rail. 311 , reflow I 13 The reflux of the separated portion | 133 The flow still passes through the running track itself, i.e., the internal resistance R of the parallel section. 311 At the end of the second connecting line 102 of the running rail, the return flow I 13 Partial reflux I 132 Flow through inductor L 311 (including its internal resistance R) 312 The parallel branch of the first connecting line 101 of the running rail then flows to the negative terminal of substation 8. This process is carried out by inductor L. 311 For reflux I 132 Filtering the harmonic components;

[0206] The return current I12 flows back to the negative terminal of the substation 7 via the wheel 6 and the running rail. At this time, the filter connection unit 2 of Scheme 3 has an inductor L connected in parallel on the physically continuous running rail. 321 , reflow I 12 The reflux of the separated portion I 124 The flow still passes through the running track itself, i.e., the internal resistance R of the parallel section. 321 At the end of the first connecting line 201 of the running rail, the return flow I 12 Partial reflux I 122 Flow through inductor L 321 (including its internal resistance R) 322 The parallel branch of the second connecting line 202 of the running rail then flows to the negative terminal of substation 7. This process is carried out by inductor L. 321 For reflux I 122 The harmonic components are filtered; at this time, the filter connection unit 3 of Scheme 3 is connected in parallel with inductor L on a physically continuous running track. 331 The reflux I12 branched out reflux I 125 The flow still passes through the running track itself, i.e., the internal resistance R of the parallel section. 331 At the end of the first connecting line 301 of the running rail, the return flow I 12 Partial reflux I 123 Flow through inductor L 331 (including its internal resistance R) 332 The parallel branch of the second connecting line 302 of the running rail then flows to the negative terminal of substation 7. This process is carried out by inductor L. 331 For reflux I 123 Filtering the harmonic components;

[0207] Fig. 7(c) is a current flow chart of the filter connection unit 1 of scheme three, the filter connection unit 2 of scheme three, and the filter connection unit 3 of scheme three before the train accelerates and enters a uniform speed state. When the train 5 starts and accelerates as shown in Fig. 2(d) and passes the position of the filter connection unit 2 of scheme three, the filter connection unit 2 of scheme three is in parallel on the physically continuous running rail, and the return current I 321 , the return current I 13 is branched 135 and still flows through the running rail itself, i.e. the parallel section internal resistance R 321 , and at the end of the running rail second connection line 202, the return current I 13 branched 134 part flows through the inductor L 321 (including its internal resistance R 322 ), the parallel branch at the end of the running rail first connection line 201, and then flows to the negative terminal of the substation 8. This process filters the harmonic components of the return current I 321 by the inductor L 134 ;

[0208] At this time, the filtering mode of the filter connection unit 1 of scheme three and the filter connection unit 3 of scheme three remains unchanged as shown in Fig. 7(b).

[0209] Technical solution four of the present application:

[0210] See Figure 8 ;

[0211] Technical solution four of the present application is composed and combined with technical solution three of the present application on the basis of technical solution one of the present application;

[0212] As shown in Figure 8 , the filter connection unit 1 of scheme one still consists of the first parallel branch of the running rail first connection line 101 end, the running rail second connection line 102 end and the running rail welded connection, and the filter connection unit 1 of scheme three is placed in the periphery of the filter connection unit 1 of scheme one, and is welded and connected by the running rail third connection line 141 end, the running rail fourth connection line 142 end and the running rail, to increase the bidirectional conduction IGBT switch Q 411 between the inductor L 413 (including the internal resistance R 411 ) and the running rail fourth connection line 142 end, to form the second parallel branch;

[0213] Among them, the running rail third connection line 141 end is connected to the 143 end of the inductor L 411 , the 144 end of the inductor L 411 is connected to the 145 end of the bidirectional conduction IGBT switch Q 411 , and the 145 end of the bidirectional conduction IGBT switch Q 411End 146 is connected to end 142 of the fourth connecting line of the running rail;

[0214] The welding connections between the third connecting line 141 and the fourth connecting line 142 of the running rail and the running rail are brazing.

[0215] Based on the above scheme, the third connecting line 141 and the fourth connecting line 142 of the running rail still maintain physical continuity of the running rail as a whole, including the internal resistance R of the parallel section of the running rail. 411 Internal resistance R of the parallel section of the running track 412 ;

[0216] Based on the above scheme, the bidirectional IGBT switch Q 421 It possesses intelligent control capabilities and is controlled by a control chip. Its function is to control the supercapacitor C in the filter connection unit 1 of Scheme 1. 111 During charging, the control switch itself disconnects, causing capacitor C to... 111 The resistance R in the parallel section of the running track 111 Charging under the voltage formed within the segment.

[0217] like Figure 8 As shown, in Scheme 1, the filter connection unit 2 is still formed by welding the first connecting line 201 and the second connecting line 202 of the running rail to the running rail to form a first parallel branch. In Scheme 3, the filter connection unit 2 is placed around the filter connection unit 2 of Scheme 1, and is welded to the running rail by the third connecting line 241 and the fourth connecting line 242 of the running rail. 421 (including internal resistance R) 423 A bidirectional IGBT switch Q is added between the fourth connecting line 242 and the running rail. 421 This forms the second parallel branch;

[0218] The third connecting line 241 of the running track is connected to an inductor L. 421 Terminal 243, inductor L 421 The 244 terminal is connected to the bidirectional IGBT switch Q. 421 The 245 terminal is connected to the bidirectional IGBT switch Q. 421 End 246 is connected to end 242 of the fourth connecting line of the running rail;

[0219] The welding connections between the third connecting line 241 and the fourth connecting line 242 of the running rail and the running rail are brazing.

[0220] Based on the above scheme, the third connecting line 241 end and the fourth connecting line 242 end of the running rail still maintain the overall physical continuity of the running rail, including the internal resistance R of the parallel section of the running rail. 421 Internal resistance R of the parallel section of the running track422 ;

[0221] Based on the above scheme, the bidirectional IGBT switch Q 421 It possesses intelligent control capabilities and is controlled by a control chip. Its function is to control the supercapacitor C in the filter connection unit 2 of scheme one. 121 During charging, the control switch itself disconnects, causing capacitor C to... 121 The resistance R in the parallel section of the running track 121 Charging under the voltage formed within the segment.

[0222] like Figure 8 As shown, in Scheme 1, the filter connection unit 3 is still formed by welding the first connecting line 301 and the second connecting line 302 of the running rail to the running rail to form a first parallel branch. In Scheme 3, the filter connection unit 3 is placed around the filter connection unit 3 of Scheme 1, and is welded to the running rail by the third connecting line 341 and the fourth connecting line 342 of the running rail. In the inductor L... 431 (including internal resistance R) 433 A bidirectional IGBT switch Q is added between the fourth connecting line 342 and the running rail. 431 This forms the second parallel branch;

[0223] The third connecting line 341 of the running track is connected to an inductor L. 431 Terminal 343, inductor L 431 The 344 terminal and the bidirectional IGBT switch Q 431 The 345 terminal is connected to the bidirectional IGBT switch Q. 431 End 346 is connected to end 342 of the fourth connecting line of the running rail;

[0224] The welding connections between the third connecting line 341 and the fourth connecting line 342 of the running rail and the running rail are brazing.

[0225] Based on the above scheme, the third connecting line 341 and the fourth connecting line 342 of the running rail still maintain physical continuity of the running rail as a whole, including the internal resistance R of the parallel section of the running rail. 431 Internal resistance R of the parallel section of the running track 432 ;

[0226] Based on the above scheme, the bidirectional IGBT switch Q 431 It possesses intelligent control capabilities and is controlled by a control chip. Its function is to control the supercapacitor C in the filter connection unit 3 of Scheme 1. 13 1. During charging, the control switch itself disconnects, causing capacitor C to... 131 The resistance R in the parallel section of the running track 131 Charging under the voltage formed within the segment.

[0227] Embodiment:

[0228] The method for reducing the stray current generated by the power return flow of the metro running rail, the technical solution four of the present application is formed on the basis of the technical solution one of the present application and the technical solution three of the present application, and the embodiment is:

[0229] Figure 8 For the connection unit structure diagram of the technical solution four of the present application, when the train 5 enters the station and brakes as shown in FIG. 2(b), the first parallel branch composed of the filter connection unit 1 of the technical solution one, the filter connection unit 2 of the technical solution one and the filter connection unit 3 of the technical solution one still operates in the embodiment of the technical solution one of the present application; at this time, the bidirectional conduction IGBT switch Q 411 of the filter connection unit 1 of the technical solution three, the bidirectional conduction IGBT switch Q 421 of the filter connection unit 2 of the technical solution three and the bidirectional conduction IGBT switch Q 431 of the filter connection unit 3 of the technical solution three are all turned off, so that all the super capacitors in the filter connection unit 1 of the technical solution one, the filter connection unit 2 of the technical solution one and the filter connection unit 3 of the technical solution one are charged under the voltage formed in the resistance section of the respective running rail parallel section.

[0230] When the train 5 starts to run and accelerates away from the station platform as shown in FIG. 2(c) and FIG. 2(d), at this time, the first branch composed of the filter connection unit 1 of the technical solution one, the filter connection unit 2 of the technical solution one and the filter connection unit 3 of the technical solution one still operates in the embodiment of the technical solution one of the present application; the bidirectional conduction IGBT switch Q 411 of the filter connection unit 1 of the technical solution three, the bidirectional conduction IGBT switch Q 421 of the filter connection unit 2 of the technical solution three and the bidirectional conduction IGBT switch Q 431 of the filter connection unit 3 of the technical solution three are all turned on to operate the second parallel branch, so as to operate in the embodiment of the technical solution three of the present application and further enhance the filtering function of the return flow harmonic component.

[0231] The technical solution four of the present application controls all the bidirectional conduction IGBT switches and all the contactor contacts in all the units through the control chip, regulates the change of the current direction of the super capacitor, and protects the possible overvoltage and overcurrent.

[0232] When any inductance or super capacitor in any parallel branch of any unit fails, the bidirectional conduction IGBT switch of the unit is immediately turned off to restore to the state before the present application is used, and will not cause any impact on the train operation.

[0233] The above description is merely preferred specific embodiments of the present application, but the protection scope of the present application is not limited thereto, and any person skilled in the art can easily think of changes or replacements within the technical scope disclosed by the present application, which should be covered within the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

[0234] The contents not described in detail in the specification belong to the prior art known to the person skilled in the art.

Claims

1. A method for reducing stray current caused by power supply return current in subway running tracks, characterized in that: A filtering method is adopted to address the return harmonic components of the running rail itself, which serves as a source of miscurrent. This involves maintaining the continuity of the physical rails while using a parallel connection of inductors, supercapacitors, IGBT switches, and contactors. By controlling the contacts of the IGBT switches and contactors, the supercapacitors are discharged, creating a voltage that blocks the forward current of the parallel rail section. This forces the current to flow through the parallel branch formed by the series connection of the inductor, supercapacitor, IGBT switch, and contactor, effectively filtering the return harmonic components.

2. The method as described in claim 1, characterized in that, When the physical rails of the running track are discontinuous, an inductor is connected in parallel to effectively filter the harmonic components of the return current.

3. A system for implementing the method of reducing the flow of power supply return current generated by subway running rails as claimed in claim 1 or 2, characterized in that: The system includes filter connection unit 1, filter connection unit 2, and filter connection unit 3; Specifically, the filter connection unit 1 is electrically connected at the web of the running track at the rear of the train when the train 5 stops at the station platform, and is connected in parallel with the running track; the filter connection unit 2 is electrically connected at the web of the running track at the front of the train when the train 5 stops at the station platform, and is connected in parallel with the running track; the filter connection unit 3 is electrically connected at the web of the running track at the moment when the train 5 finishes accelerating and enters a constant speed state, and is connected in parallel with the running track.

4. The system as described in claim 3, characterized in that, Each of the aforementioned filter connection units is connected to the running rail and is an independent operating device, not connected to each other.

5. The system as described in any one of claims 3-4, characterized in that, Each of the plurality of filter connection units includes at least one inductor, the inductor being used to block harmonic components of the return current from the running track.

6. The system as described in claim 5, characterized in that, At least one of the filter connection units includes at least one supercapacitor and at least one switch, wherein the supercapacitor, the switch, and the inductor are connected in series; wherein the supercapacitor is used to discharge in the filter connection unit to form a current loop and block the forward current of the parallel rail segment.

7. The system as described in claim 6, characterized in that, The filter connection unit includes at least one contactor module, which is used to adjust the direction of the current flowing through the supercapacitor.

8. The system as described in claim 7, characterized in that, The contactor module includes multiple normally open contacts and / or normally closed contacts, and the supercapacitor is connected in parallel and / or in series with the multiple normally open contacts and / or normally closed contacts.

9. The system according to any one of claims 6-8, characterized in that, The switch is a bidirectional IGBT switch, used to control the forward and reverse flow of current, and to regulate and protect against possible overvoltage and overcurrent during energy storage and discharge of the supercapacitor.

10. The system as described in claim 5, characterized in that, The system includes an insulating joint at the web of the running rail, and at least one of the filtering connection units can be connected in parallel with the web of the running rail through the insulating joint; the insulating joint is used to block the current loop of the running rail.

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