Negative voltage backflow direct current supply system for rail transport

Patent metadata

Field	Value
Publication number	US-10744880-B2
Application number	US-201615746519-A
Country	US
Kind code	B2
Filing date	Jun 22, 2016
Priority date	Jul 22, 2015
Publication date	Aug 18, 2020
Grant date	Aug 18, 2020

Abstract

A negative voltage backflow direct current supply system for a rail transport is provided. The system adds a negative voltage return line and a DC converter for realizing negative voltage backflow current based on traditional DC power supply system. The negative voltage backflow line replaces the backflow line of running rail in the traditional DC power supply system, which can greatly reduce or eliminate the stray current in the traditional DC power supply system and the negative influence of too high ground potential of running rail. At the same time, the DC converter can be used as regenerative braking energy storage device of train to improve the regenerative braking energy utilization efficiency of DC power supply system and maintain the voltage stability of DC power supply system of rail transport.

First claim

What is claimed is:

1. A negative voltage backflow direct current supply system for a rail transport comprising: a DC traction substation with two-level output or three-level output ( 1 ), a positive voltage feeder ( 2 ), a running rail ( 3 ), a negative voltage backflow line ( 4 ) and a plurality of DC converters ( 5 );
said negative voltage backflow line ( 4 ) is arranged along the running rail ( 3 );
said a plurality of DC converters are arranged along the running rail ( 3 );
when the DC traction substation is two-level output, a connecting mode is: a positive end ( 11 ) of the DC traction substation ( 1 ) is connected to the positive voltage feeder ( 2 ), a negative end ( 12 ) of the DC traction substation ( 1 ) is connected to the running rail ( 3 ), a high potential terminal ( 51 ) of the DC converter ( 5 ) is connected to the positive voltage feeder ( 2 ), a neutral potential terminal ( 53 ) of the DC converter ( 5 ) is connected to the running rail ( 3 ), and a low potential terminal ( 52 ) of the DC converter ( 5 ) is connected to the negative voltage backflow line ( 4 );
when the DC traction substation is three-level output, a connecting mode is: a positive end ( 11 ) of the DC traction substation ( 1 ) is connected to the positive voltage feeder ( 2 ), the midpoint ( 13 ) of the DC traction substation ( 1 ) is connected to the running rail ( 3 ), the negative end ( 12 ) of the DC traction substation ( 1 ) is connected to the negative voltage backflow line ( 4 ), a high potential terminal ( 51 ) of the DC converter ( 5 ) is connected to the positive voltage feeder ( 2 ), a neutral potential terminal ( 53 ) of the DC converter ( 5 ) is connected to the running rail ( 3 ), and a low potential terminal ( 52 ) of the DC converter ( 5 ) is connected to the negative voltage backflow line ( 4 ).

2. The system of claim 1 , wherein, a current of the DC converter ( 5 ) flows in from the neutral potential terminal ( 53 ) and flows out from the high potential terminal ( 51 ) and the low potential terminal ( 52 ) simultaneously, the voltage value between the high potential terminal ( 51 ) and the neutral potential terminal ( 53 ) is equal or unequal to the value between the neutral potential terminal ( 53 ) and the low potential terminal ( 52 ), when the values are equal, the current values of the high potential terminal ( 51 ) and the low potential terminal ( 52 ) simultaneously flows in or flows out are also equal.

3. The system of claim 1 , wherein, the number of DC converter ( 5 ) and the distance of a running rail section between the two adjacent DC converters ( 5 ) are determined by the number of output level of the DC traction substation, the length of power supply line, train's load and train running rail interval and other factors; the running rail section between the two adjacent DC converters ( 5 ) or between the DC converter ( 5 ) and the DC traction substation ( 1 ) only for one train running is optimization of the distance of running rail section.

4. The system of claim 1 , wherein, when the DC traction substation is two-level output and there is a train on the running rail;
in the case that at least one section of the most adjacent running rail sections on both sides of the connecting point between the neutral potential terminal ( 53 ) of the DC converter ( 5 ) which is not most adjacent to the DC traction substation ( 1 ) and the running rail ( 3 ) has a train ( 6 ) running, the DC converter ( 5 ) transfers the current from the train ( 6 ) to the running rail ( 3 ) into output of high potential terminal ( 51 ) and output of low potential terminal ( 52 ) through input of the neutral potential terminal ( 53 ), of which output current of high potential terminal ( 51 ) is fed back to the train ( 6 ), and output current of low potential terminal ( 52 ) is transmitted to the negative voltage backflow line ( 4 );
the DC converter ( 5 ) which is the most adjacent to DC traction substation ( 1 ) converts the current of the negative voltage backflow line ( 4 ) flowed from the low potential terminal ( 52 ) and the current of the positive voltage feeder ( 2 ) flowed from the high potential terminal ( 51 ) into the output current of the neutral potential terminal ( 53 ); then this output current is directly returned to the DC traction substation ( 1 ) which supplies power for the train ( 6 );
in the case that the most adjacent running rail sections on both sides of the connecting point between the neutral potential terminal ( 53 ) of the DC converter ( 5 ) which is not most adjacent to DC traction substation ( 1 ) and the running rail ( 3 ) has no train ( 6 ) running, there is no current on the sections and three terminals of the DC converter ( 5 ).

5. The system of claim 4 , wherein, when the neutral potential terminal ( 53 ) of the DC converter ( 5 ) which is the most adjacent to DC traction substation ( 1 ) is connected to the running rail ( 3 ) after being connected to the negative end ( 12 ) of the DC traction substation ( 1 ), and when the running rail has a train running, the current of the most adjacent running rail sections on both sides of the connecting point between the DC traction substation ( 1 ) and the running rail ( 3 ) is minimum.

6. The system of claim 1 , wherein, when the DC traction substation is three-level output and there is a train on the running rail;
in the case that at least one section of the most adjacent running rail sections on both sides of the connecting point between the neutral potential terminal ( 53 ) of the DC converter ( 5 ) and the running rail ( 3 ) has a train ( 6 ) running, the DC converter ( 5 ) transfers the current from the train ( 6 ) to the running rail ( 3 ) into output of high potential terminal ( 51 ) and output of low potential terminal ( 52 ) through input of the neutral potential terminal ( 53 ), of which output current of high potential terminal ( 51 ) is fed back to the train ( 6 ), and output current of low potential terminal ( 52 ) is directly returned to the DC traction substation ( 1 ) through its negative end ( 12 ) after being transmitted to the negative voltage backflow line ( 4 );
in the case that the most adjacent running rail sections on both sides of the connecting point between the neutral potential terminal ( 53 ) of the DC converter ( 5 ) which is not most adjacent to DC traction substation ( 1 ) and the running rail ( 3 ) has no train ( 6 ) running, there is no current on the sections and three terminals of the DC converter ( 5 ).

7. The system of claim 6 , wherein when the neutral potential terminal ( 53 ) of the DC converter ( 5 ) which is the most adjacent to DC traction substation ( 1 ) and the midpoint ( 13 ) of the DC traction substation ( 1 ) are respectively connected to the rail line ( 3 ), and when the running rail section between these two connecting points has a train ( 6 ) running, the current from the positive end ( 11 ) of the DC traction substation ( 1 ) and the current from the negative end ( 12 ) are not equal.

8. The system of claim 6 , wherein, said DC converter ( 5 ) contains two sets of capacitors (C 51 ) and (C 52 ), of which one of the two sets of capacitors, (C 51 ), is connected between the high potential terminal ( 51 ) and the neutral potential terminal ( 53 ) of the DC converter ( 5 ), and another of the two sets of capacitors, (C 52 ), is connected between the neutral potential terminal ( 53 ) and the low potential terminal ( 52 ) of the DC converter ( 5 ).

9. The system of claim 8 , wherein after the two sets of capacitors (C 51 ) and (C 52 ) of the DC converter are replaced or partially replaced by an energy storage unit, the DC converter ( 5 ) not only has a function of negative voltage conversion, but also has a function of regenerative braking

Assignees

• Beijing Efficiengine Tech Llc
• Univ Beijing Jiaotong

Inventors

• Zheng Qionglin
• Yang Xiaofeng
• You Xiaojie
• Hao Ruixiang
• Li Hong

Classifications

• Y02T10/70

  Energy storage systems for electromobility, e.g. batteries · CPC title

• B60L50/53

  in combination with an external power supply, e.g. from overhead contact lines · CPC title

• Y02T10/72

  Electric energy management in electromobility · CPC title

• B60M3/06 Primary

  Arrangements for consuming regenerative power · CPC title

• B60L2200/26

  Rail vehicles · CPC title