CN113829929B

CN113829929B - Train, train control method and train charging system control method

Info

Publication number: CN113829929B
Application number: CN202010591070.4A
Authority: CN
Inventors: 佘红涛; 谭志成; 鲁豪; 郭名扬; 马栋茂
Original assignee: BYD Co Ltd
Current assignee: BYD Co Ltd
Priority date: 2020-06-24
Filing date: 2020-06-24
Publication date: 2023-04-07
Anticipated expiration: 2040-06-24
Also published as: CN113829929A

Abstract

The embodiment of the application discloses a train, wherein BMSs of all carriages of the train are used for receiving a charging notification instruction sent by a vehicle controller; the BMS is used for performing handshake identification with the charging station through the carriage communication module when receiving a handshake message sent by the charging station according to the charging notification instruction; the BMS is also used for carrying out charging preparation under the condition that the handshake identification with the charging station is confirmed to be successful; the charging preparation comprises the steps of controlling a traction loop to stop supplying power to a compartment power running module when the train is in a high-voltage power-on state, or controlling a DC loop to be conducted when the train is in a low-voltage power-on state; the BMS is also used for sending a charging request message to the charging station through the carriage communication module after confirming that the charging preparation is completed. By adopting the method and the device, when the train is in a high-voltage charging mode, the safety of the train in a charging stage can be improved; when the train is in the low-voltage charging mode, the electric quantity of the energy storage battery is ensured to be sufficient.

Description

Train, train control method and train charging system control method

Technical Field

The invention relates to the technical field of rail transit, in particular to a train, a train control method and a train charging system control method.

Background

Along with the development of rail transit technology, the charging problem of a power battery of a train compartment is more and more concerned, the existing charging technology is mainly divided into two modes, and when a train is in a high-voltage charging mode, the condition of a motor train occurs in the charging process; when the train is in the low-voltage charging mode, the train is supplied with power to the carriage low-voltage load by the energy storage battery in the whole charging process, but the electric quantity stored by the energy storage battery is limited, and the condition that the charging process cannot be completed due to insufficient electric quantity of the energy storage battery exists.

Disclosure of Invention

The embodiment of the application provides a train, a train control method and a train charging system control method, aiming at improving the safety of the train in a charging stage when the train is in a high-voltage charging mode; when the train is in a low-voltage charging mode, the electric quantity of the energy storage battery is ensured to be sufficient.

In a first aspect, a train is provided for an embodiment of the present application, the train includes a vehicle controller and at least one car, each car in the at least one car includes a BMS battery management system, a DC loop, a traction loop and a car communication module, the DC loop is used for inputting a car low-voltage load after reducing the voltage of a car power battery, the traction loop is used for inputting a car power running module after inverting the voltage of the car power battery, wherein:

the BMS is used for receiving a charging notification instruction sent by the vehicle controller;

the BMS is used for performing handshake identification with the charging station through the carriage communication module when receiving a handshake message sent by the charging station according to the charging notification instruction;

the BMS is used for carrying out charging preparation under the condition that the handshake identification with the charging station is successful; the charging preparation comprises the steps of controlling the traction circuit to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state;

and the BMS is also used for sending a charging request message to the charging station through the carriage communication module after the charging preparation is confirmed to be completed, wherein the charging request message is used for controlling the corresponding charging bow to fall.

In a second aspect, a control method for a train is provided for an embodiment of the present application, where the train includes a vehicle controller and at least one car, and each car of the at least one car includes a BMS battery management system, a DC loop, a traction loop and a car communication module, where the DC loop is configured to step down a voltage of a car power battery and input the voltage to a car low-voltage load, and the traction loop is configured to invert the voltage of the car power battery and input the voltage to a car power running module;

the method comprises the following steps:

the BMS receives a charging notification instruction sent by the vehicle controller;

the BMS conducts handshake identification with the charging station through the carriage communication module when receiving handshake messages sent by the charging station according to the charging notification instruction;

in case of confirming that the handshake recognition with the charging station is successful, the BMS performs charging preparation; the charging preparation comprises the steps of controlling the traction circuit to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state;

and after confirming that the charging preparation is completed, the BMS sends a charging request message to the charging station through the carriage communication module, wherein the charging request message is used for controlling the corresponding charging bow to reduce the bow of the charging station.

In a third aspect, a train charging system is provided for an embodiment of the present application, the train charging system includes a train and a charging station, the train includes a vehicle controller and at least one car, each car in the at least one car includes a BMS battery management system, a DC direct current loop, a traction loop car communication module and a car current collector, the DC loop is configured to step down a voltage of a car power battery and input the voltage to a car low voltage load, the traction loop is configured to invert the voltage of the car power battery and input the inverted voltage to a car power running module, the charging station includes at least one charging bow, where:

the BMS is connected with the vehicle controller and used for receiving a charging notification instruction sent by the vehicle controller;

the BMS is connected with the carriage communication module and used for performing handshake identification with the charging station through the carriage communication module when receiving a handshake message sent by the charging station according to the charging notification instruction;

the BMS is respectively connected with the traction loop and the DC loop and used for carrying out charging preparation under the condition of confirming successful handshake identification with the charging station;

the charging preparation comprises the steps of controlling the traction circuit to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state;

the BMS is used for sending a charging request message to the charging station through the carriage communication module after the charging preparation is confirmed to be completed;

the charging station is used for sending a handshake message to the BMS;

the charging station is used for controlling the corresponding charging bow to fall according to the charging request message;

and the charging station is also used for charging the train under the condition that the connection state of the charging bow and the corresponding carriage current collector is normal connection.

In a fourth aspect, a control method of a train charging system is provided for an embodiment of the present application, where the train charging system includes a train and a charging station, the train includes a vehicle controller and at least one car, each car in the at least one car includes a BMS battery management system, a DC direct current loop, a traction loop, a car communication module and a car current collector, the DC loop is configured to step down a voltage of a car power battery and input the voltage to a car low-voltage load, the traction loop is configured to invert the voltage of the car power battery and input the voltage to a car power running module, and the charging station includes at least one charging bow;

the method comprises the following steps:

the charging station sends a handshake message to the BMS;

the BMS performs charging preparation under the condition that the BMS confirms successful handshake identification with the charging station;

after confirming that the charging preparation is completed, the BMS sends a charging request message to the charging station through the carriage communication module;

the charging station controls the corresponding charging bow to fall according to the charging request message;

and the charging station charges the train under the condition that the charging bow is normally connected with the carriage current collector.

In this application embodiment, the train includes vehicle controller and at least one carriage, and each carriage in at least one carriage includes BMS battery management system, DC return circuit, traction circuit and carriage communication module, and the DC return circuit is used for inputing carriage low pressure load after stepping down carriage power battery's voltage, and traction circuit is used for inputing carriage power driving module after inverting carriage power battery's voltage, wherein: the BMS is used for receiving a charging notification instruction sent by the vehicle controller; the BMS is used for performing handshake identification with the charging station through the carriage communication module when receiving a handshake message sent by the charging station according to the charging notification instruction; the BMS is used for carrying out charging preparation under the condition of confirming that the handshake identification with the charging station is successful; the charging preparation comprises the steps of controlling a traction circuit to stop supplying power to a compartment power running module when a train is in a high-voltage power-on state, or controlling a DC circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state; the BMS is also used for sending a charging request message to the charging station through the carriage communication module after confirming that the charging preparation is finished, wherein the charging request message is used for controlling the corresponding charging bow reduction of the charging station. By adopting the method and the device, when the train is in a high-voltage charging mode, the safety of the train in a charging stage can be improved; when the train is in the low-voltage charging mode, the electric quantity of the energy storage battery is ensured to be sufficient.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a schematic scene diagram of a control method of a train charging system according to an embodiment of the present disclosure;

fig. 2 is a schematic system architecture diagram of a train charging system according to an embodiment of the present disclosure;

fig. 3 is a schematic flowchart of a control method of a train charging system according to an embodiment of the present disclosure;

fig. 4 is a schematic diagram of a traction circuit and a DC circuit of each car of a train according to an embodiment of the present application;

fig. 5 is a schematic diagram of a human-machine interface for displaying a VIN of a train to be charged according to an embodiment of the present application;

fig. 6 is a schematic flowchart of a control method of a train charging system according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Fig. 1 is a schematic view of a scene of a control method of a train charging system according to an embodiment of the present application. As shown in fig. 1, the train charging system includes a train 10 and a charging station 11 disposed on the ground, wherein the train 10 includes a first car 100, a second car 101, and a third car 102; the charging station 11 includes a charging bow 110, a charging bow 111, and a charging bow 112.

For convenience of describing a scenario of a control method of a train charging system, please refer to fig. 2, which is a schematic diagram of a system architecture of a train charging system according to an embodiment of the present application. As shown in fig. 2, the train charging System 2 includes a train 21 (train 10 in fig. 1) and a charging station 22 (charging station 11 in fig. 1), the train 21 includes a vehicle controller 211 and n cars, where n is a positive integer greater than or equal to 1, and here, the first car is taken as an example for description, the first car (first car 100 in fig. 1) includes a Battery Management System (BMS) 212, a Direct Current (DC) loop 213, a traction loop 214, a car communication module 215, a car Current collector 216 and a radio frequency tag 217, wherein the BMS212 is respectively connected with the vehicle controller 211 and the car communication module 215, and further, the BMS212 is respectively connected with the DC loop 213 and the traction loop 214 through communication harnesses, the DC loop 213 is used for inputting the voltage of a car power Battery after being reduced to a car low-voltage load, and the traction loop 214 is used for inputting the voltage of the car power Battery after being inverted to a running power module; the car communication module 215 is used to provide wireless communication connections; the train car current collector 216 is used for being electrically connected with the charging bow when the train 21 needs to be charged; the radio frequency tag 217 is arranged on the train 21, the tag stores the vehicle information of the train, the vehicle information includes a running direction and a vehicle identification code, it should be noted that the radio frequency tag 217 may be arranged in each carriage, or in the first and last carriages, and the arrangement mode is not limited herein; the charging station 22 comprises a charging arch 221 and a line communication module 222, wherein the charging arch 221 comprises a charging arch 1, \8230; the line communication module 222 comprises line communication modules 1, \8230andn.

With reference to fig. 1 and fig. 2, a scenario of a control method of a train charging system is described below according to a sequence of a train being in a high-voltage power-on state and a train being in a low-voltage power-on state.

In one possible embodiment, after the train 10 stops at the charging position and stops stably, the charging personnel operates the parking brake knob to make the train 10 in the parking brake applying state, and operates the high-voltage power-on button in the console to make the train 10 in the high-voltage power-on state, that is, the DC circuit and the traction circuit of each car are both in the conducting state, at this time, the charging personnel turns on the charging knob, and the vehicle controller 211 receives the charging signal sent by the charging personnel by turning on the charging knob.

Further, after the train 10 is in a high-voltage power-on state by operating a high-voltage power-on button in the console by a charging operator, the operating mode is switched to an automatic mode, when the dispatching system confirms that the train is in a sequence requiring charging, a message that the train needs to be charged is sent to the signal system, the signal system sends a charging location operation instruction to the train according to the message that the train needs to be charged, the train 10 operates to a preset charging location according to the charging location operation instruction, and the signal system sends a charging signal to the train 10 after detecting that the train 10 is in the preset charging location.

After receiving the charging signal, the vehicle controller 211 controls the low-voltage relays of each car to pull in, so that the energy storage battery of each car supplies power to the car communication module of each car, and the vehicle controller 211 sends a charging notification command and a charging request message to the BMS of each car, here, taking the first car 100 as an example, the BMS212 performs handshake recognition with the charging station 22 through the car communication module 215 upon receiving the handshake message sent by the charging station 22 according to the received charging notification command, and controls the traction circuit 214 to stop working if confirming that the handshake recognition with the charging station 22 is successful, and the BMS212 sends the received charging request message to the charging station 22 through the car communication module 215 upon confirming that the traction circuit 214 does not work, and after receiving the charging request message through the line communication module 1 in the line communication module 222, the charging station 22 controls the charging bow 110 corresponding to the first car 100 in the charging bow 221 to descend, and when detecting that the connection between the charging bow 110 and the current collector 216 is normal, stops detecting the connection state between the charging bow 110 and the current collector 216, and enters the charging station 211 configures parameters of the charging station 100, and configures the charging parameters of the first car 100 according to the configuration parameters of the charging bow 100.

In another possible embodiment, after the train 10 is stopped at the charging position and is quasi-stationary, the charging personnel operates the parking brake knob to make the train 10 in the parking brake applying state, and operates the low-voltage power-on button in the console to make the train 10 in the low-voltage power-on state, that is, the DC circuit and the traction circuit of each car are both in the disconnection state, at this time, the charging personnel turns on the charging knob, and the vehicle controller 211 receives the charging signal sent by the charging personnel by turning on the charging knob.

Further, after the train 10 is in a low-voltage power-on state by operating a low-voltage power-on button in the console by a charging operator, the working mode is switched to an automatic mode, a message that the train needs to be charged is sent to the signal system under the condition that the dispatching system confirms that the train is in a sequence that the train needs to be charged, the signal system sends a charging location operation instruction to the train according to the message that the train needs to be charged, the train 10 operates to a preset charging location according to the charging location operation instruction, and the signal system sends a charging signal to the train 10 after detecting that the train 10 is in the preset charging location.

After receiving the charging signal, the vehicle controller 211 controls the low-voltage relay in each car to pull in, so that the energy storage battery in each car supplies power to the car communication module 215, and the vehicle controller 211 sends a charging notification command and a charging request message to the BMS in each car, here, taking the first car 100 as an example, the BMS212 performs handshake recognition with the charging station 22 through the car communication module 215 upon receiving the handshake message sent by the charging station 22, and controls the DC circuit 214 to conduct, the DC circuit 214 operates normally, the power supply of the low-voltage load of the car changes from the energy storage battery to the DC circuit 214, so as to ensure that the energy storage battery is charged sufficiently, and when the BMS212 confirms that the DC circuit 214 is conducted, the received charging request message is sent to the charging station 22 through the car communication module 215, after the charging request message is received through the line communication module 1 in the line communication module 222, the charging bow 110 in the charging bow 221 is controlled to fall, and the charging bow 110 is detected to be connected with the charging station 110, and the charging station 22 is configured according to the charging parameters of the charging bow 216, and the charging configuration of the charging station 100 is detected, and the charging parameters of the charging station 100 are detected.

A train charging system according to the present application will be described with reference to the accompanying drawings, and please refer to fig. 2 again. As shown in fig. 2, the train charging system 2 includes a train 21 and a charging station 22, the train 21 includes a vehicle controller 211 and at least one car, each car of the at least one car includes a BMS battery management system 212, a DC direct current loop 213, a traction loop 214, a car communication module 215, and a car current collector 216, the DC loop 213 is configured to step down a voltage of a car power battery and input the voltage to a car low voltage load, the traction loop 214 is configured to invert the voltage of the car power battery and input the voltage to a car power running module, the charging station 22 includes at least one charging bow 221, wherein:

the BMS212 is connected to the vehicle controller 211, and is configured to receive a charging notification instruction sent by the vehicle controller 211;

the BMS212 is connected to the car communication module 215, and is configured to perform handshake identification with the charging station 22 through the car communication module 215 when receiving a handshake message sent by the charging station 22 according to the charging notification instruction;

the BMS212 is connected to the traction circuit 214 and the DC circuit 213, respectively, for performing charging preparation in case of confirming successful handshake recognition with the charging station 22;

the charging preparation comprises the steps of controlling the traction circuit 214 to stop supplying power to the compartment power running module when the train 21 is in a high-voltage power-on state, or controlling the DC circuit 213 to be conducted when the train 21 is in a low-voltage power-on state, wherein the DC circuit 213 and the traction circuit 214 are both in a conducting state when the train 21 is in the high-voltage power-on state, and the DC circuit 213 and the traction circuit 214 are both in a disconnecting state when the train 21 is in the low-voltage power-on state;

the BMS212 is configured to send a charging request message to the charging station 22 through the car communication module 215 after confirming that the charging preparation is completed;

the charging station 22 is configured to send a handshake message to the BMS 212;

the charging station 22 is configured to control the corresponding charging bow 221 to bow according to the charging request message;

the charging station 22 is also configured to charge the train 21 when it is confirmed that the charging bow 221 is normally connected to the corresponding car current collector 216.

A train according to the present application will be described with reference to the accompanying drawings, and please refer to fig. 2 again. As shown in fig. 2, the train 21 includes a vehicle controller 211 and at least one car, each of the at least one car includes a BMS battery management system 212, a DC circuit 213, a traction circuit 214, and a car communication module 215, the DC circuit 213 is configured to step down a voltage of a car power battery and input the voltage to a car low-voltage load, and the traction circuit 214 is configured to invert the voltage of the car power battery and input the voltage to a car power running module, wherein:

the BMS212 is connected to the car communication module 215, and is configured to perform handshake recognition with the charging station 22 through the car communication module 215 when receiving a handshake message sent by the charging station 22 according to the charging notification instruction;

the BMS212 is connected to the traction circuit 214 and the DC circuit 213, respectively, and is further configured to prepare for charging in case of confirming that the handshake recognition with the charging station 22 is successful;

the charging preparation comprises the steps of controlling the traction circuit 214 to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC circuit 213 to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit 213 and the traction circuit 214 are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit 213 and the traction circuit 214 are both in a disconnecting state when the train is in the low-voltage power-on state;

the BMS212 is further configured to send a charging request message to the charging station 22 through the car communication module 215 after confirming that the charging preparation is completed, where the charging request message is used for the charging station 22 to control the corresponding charging bow 221 to bow down.

Optionally, the traction circuit 214 includes a traction working branch, and the traction working branch is connected to a traction inverter for inputting the voltage of the car power battery to the traction inverter;

the BMS212 is configured to disconnect the traction working branch when the train is in a high-voltage power-on state, such that the traction circuit is disconnected.

Optionally, the traction circuit 214 includes a traction inverter, and the traction inverter is configured to convert the direct current output by the car power battery into an alternating current and input the alternating current to the car power running module;

the BMS212 is also configured to control the traction inverter to be in a cut-off state when the train is in a low-voltage power-on state.

Optionally, the traction circuit 214 includes a traction inverter, and the traction inverter is configured to convert the direct current output by the car power battery into an alternating current and then input the alternating current to the car power running module;

the BMS212 is further configured to control the traction circuit to be turned on and the traction inverter to be in a cut-off state when the train is in a low-voltage power-on state.

Optionally, the traction circuit 214 further includes a traction pre-charging branch and a traction working branch, where the traction pre-charging branch and the traction working branch are respectively connected to the traction inverter and are respectively used for inputting the voltage of the car power battery to the traction inverter; the BMS212 is used for controlling the conduction of the traction pre-charging branch and detecting the input voltage of the traction inverter;

the BMS212 is configured to control the traction pre-charging branch circuit to be turned off and control the traction working branch circuit to be turned on when the input voltage of the traction inverter is greater than a first preset voltage threshold.

Optionally, the DC circuit 213 includes a DC pre-charging branch, a DC working branch and a DC converter, where the DC pre-charging branch and the DC working branch are respectively connected to the DC converter and are respectively used to input the voltage of the car power battery into the DC converter, and the DC converter is used to step down the voltage of the car power battery and then input the voltage into the car low-voltage load;

the BMS212 is used for controlling the conduction of the DC pre-charging branch circuit and detecting the input voltage of the DC converter when the train is in a low-voltage power-on state;

the BMS212 is configured to control the DC pre-charging branch to be turned off and the DC working branch to be turned on when the input voltage of the DC converter is greater than a second preset voltage threshold.

Alternatively, the vehicle controller 211 is configured to send the charging notification instruction to the BMS212 when it is determined that the current state of the train is a stationary state.

For a specific implementation process and corresponding beneficial effects of the functional blocks included in the train charging system 2 and the train 21 of fig. 2, please refer to the description of the following embodiments.

Fig. 3 is a schematic flow chart of a control method of a train charging system according to an embodiment of the present disclosure. As shown in fig. 3, this method embodiment includes the steps of:

s101, the vehicle controller sends a charging notification instruction to the BMS.

Specifically, when the train is in a high-voltage power-on state or a low-voltage power-on state, the vehicle controller sends a charging notification instruction to the BMS of each car.

When the train is in a high-voltage power-on state, the DC loop and the traction loop of each carriage are in a conducting state; when the train is in a low-voltage power-on state, the DC loop and the traction loop of each compartment are in a disconnected state.

The following describes a specific implementation process of a train in a high-voltage power-on state, please refer to fig. 4, which is a schematic diagram of a traction circuit and a DC circuit of each car of the train according to an embodiment of the present application. As shown in fig. 4, the traction circuit comprises a traction pre-charging branch, a traction working branch, a traction inverter, a traction fuse and a compartment power battery, wherein the traction pre-charging branch and the traction working branch are respectively connected with the traction inverter and are respectively used for inputting the voltage of the compartment power battery into the traction inverter, the traction inverter is used for converting the direct current output by the compartment power battery into alternating current and outputting the alternating current to a compartment power driving module, in addition, the traction pre-charging branch is connected with the traction working branch in parallel, the traction pre-charging branch comprises a traction pre-charging contactor KM11 and a pre-charging resistor R, and the traction working branch comprises a traction contactor KM12; the DC loop comprises a DC pre-charging branch, a DC working branch, a DC converter, a DC fuse and a carriage power battery, wherein the DC pre-charging branch and the DC working branch are respectively connected with the DC converter and are respectively used for inputting the voltage of the carriage power battery into the DC converter, the DC converter is used for outputting the voltage of the carriage power battery to a carriage low-voltage load after reducing the voltage, in addition, the DC pre-charging branch is connected with the DC working branch in parallel, the DC pre-charging branch comprises a DC pre-charging contactor KM21 and a pre-charging resistor R, and the DC working branch comprises a DC contactor KM22.

In an alternative embodiment, after receiving a high-voltage power-on signal sent by a charger through a high-voltage power-on button in a control console, a vehicle controller controls a low-voltage relay of each car to be closed, so that an energy storage battery of each car supplies power to a low-voltage load of each car, and then sends the high-voltage power-on signal to a BMS of each car, here, taking a first car as an example, the BMS controls a traction pre-charging contactor KM21 in a traction loop of the car to be closed after receiving the high-voltage power-on signal, so that a large capacitor at an input end of the traction inverter is charged, and an input voltage of the traction inverter is continuously increased, meanwhile, the BMS receives the input voltage of the traction inverter sent by the traction inverter in real time, compares the received input voltage of the traction inverter with a first preset voltage threshold (for example, 90% of a voltage value of a power battery), and when the input voltage of the traction inverter is greater than the first preset voltage threshold, the BMS closes the traction contactor KM closing the traction contactor of a traction working branch, closes the traction contactor KM to protect the traction pre-charging contactor 12 from damage. Then, the BMS controls the attraction of the DC pre-charging contactor KM21 in the DC loop to charge a large capacitor at the input end of the DC converter, which results in an increase in the input voltage of the DC converter, and at the same time, the BMS receives the input voltage of the DC converter sent by the DC converter in real time and compares the received input voltage of the DC converter with a second preset voltage threshold (for example, 90% of the voltage value of the car power battery), when the input voltage of the DC converter is greater than the second preset voltage threshold, the BMS attracts the DC contactor KM22 of the DC working branch and disconnects the DC pre-charging contactor KM21 of the DC pre-charging branch, so that the DC loop is in a conducting state, which can be understood that the DC pre-charging branch is used to ensure that no impulse current exists when the DC contactor KM22 is closed, thereby protecting the train charging equipment from being damaged. In addition, when the DC loop is in a conducting state, the DC loop supplies power to the energy storage battery and the carriage low-voltage load, the energy storage battery does not supply power to the carriage low-voltage load any more, and the electric quantity of the energy storage battery is ensured to be sufficient. BMSs of the rest carriages enable the traction circuit and the DC circuit of the carriages to be in a conducting state according to the mode, and at the moment, the train is in a high-voltage power-on state.

In a possible embodiment, the method further comprises:

in a case where it is confirmed that the current state of the train is a stationary state, the vehicle controller transmits the charging notification instruction to the BMS.

In an alternative embodiment, when the train is in a high-voltage power-on state, when the vehicle controller receives a charging signal sent by a charging person by opening a charging knob, the vehicle controller detects a parking state signal of the train, a vehicle speed signal sent by a wheel speed sensor and a distance between the train and at least one identifier where a charging position is located, which are sent by a position sensor, and when the train is in a parking brake application state, the vehicle speed signal is 0km/h and the distance between the train and the at least one identifier where the charging position is located is within a preset distance range, the vehicle controller confirms that the train is currently located at the charging position and is in a static state, the vehicle controller controls the low-voltage relays of each car to be closed, so that the energy storage batteries of each car supply power to the communication modules of each car, and sends a charging notification instruction to the BMS of each car.

Further, the signal system sends train in-place information to the vehicle controller and the charging station when detecting that the train is located at the charging station and in a static state, and the vehicle controller controls the low-voltage relays of all the carriages to be closed after receiving the train in-place information, so that the energy storage batteries of all the carriages supply power to the carriage communication modules of all the carriages, and sends charging notification instructions to the BMS of all the carriages.

And S102, the charging station sends a handshake message to the BMS.

Before step S102 is executed, the charging stations establish communication connections with the respective cars.

Specifically, referring to fig. 2 again, as shown in fig. 2, the charging station further includes a radio frequency module, a charging controller, and a charging server, wherein the charging server is connected to the radio frequency module and the charging controller, respectively.

In an optional embodiment, the charging server reads Vehicle information stored in a radio frequency tag arranged on a train through a radio frequency module, where the Vehicle information includes a Vehicle Identification Number (VIN), and further, the radio frequency module sends the read VIN of the train to be charged to the charging controller, and the charging controller displays the identified VIN of the train to be charged after receiving the VIN of the train to be charged. For example, please refer to fig. 5, which is a schematic diagram of a human-machine interface for displaying a VIN of a train to be charged according to an embodiment of the present application. As shown in fig. 5, the charging controller displays the VIN of the train to be charged through the human-computer interaction interface shown in fig. 5a, the charger confirms whether the VIN of the train to be charged obtained through identification is consistent with the real VIN of the train to be charged by clicking a yes key or a no key in the human-computer interaction interface shown in fig. 5a, if the VIN of the train to be charged is consistent with the real VIN of the train to be charged, the charger clicks a yes key in the human-computer interaction interface shown in fig. 5a, the charging controller receives a confirmation signal sent by clicking a yes key in the human-computer interaction interface shown in fig. 5a, the charging controller can obtain the user name and the password of each carriage communication module of the train to be charged by inquiring a preset correspondence table, and sends the user name and the password of each carriage communication module to each line communication module through the charging server, and each line communication module connects each corresponding carriage communication module according to the user name and the password of each carriage communication module of each carriage, so that the charging server is connected with the BMS of each carriage in a wireless communication respectively. In this application embodiment, line communication module and carriage communication module CAN be CAN commentaries on classics WIFI module, also CAN be other buses commentaries on classics WIFI module.

After the charging server establishes wireless communication connection with the BMSs of the carriages respectively, the charging server sends handshake messages to the BMSs of the carriages.

And S103, the BMS performs handshake identification with the charging station through the carriage communication module when receiving the handshake messages sent by the charging station according to the charging notification instruction.

Specifically, the BMS of each car sends the BMS handshake message to the charging server when receiving the BMS handshake message sent by the charging server according to the charging notification instruction, the charging server stops sending the handshake message to the BMS of each car and sends a charging server identification message "0x00" to the BMS of each car after receiving the BMS handshake message "0x00" sent by the BMS of each car, the BMS of each car stops sending the BMS handshake message "0xAA" to the charging server after receiving the BMS identification message "0x00" and sends the BMS identification message "0x00" to the charging server, the charging server sends the charging server identification message "0xAA" to the BMS of each car after receiving the BMS identification message "0x00", the BMS of each car sends the BMS identification message "0xAA" to the charging server after receiving the BMS identification message "0xAA", the charging server stops sending the charging server identification message to the BMS of each car, at this time, the identification stage ends, and the charging server sends the charging parameter message to the BMS of each car. Step S104 is then performed.

And S104, when confirming that the handshake identification with the charging station is successful, the BMS performs charging preparation.

The charging preparation comprises the steps of controlling the traction circuit to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state.

The procedure of the BMS of each car preparing for charging is described below according to the case where the train is in a high-voltage power-on state and the case where the train is in a low-voltage power-on state.

Specifically, when the train is in a high-voltage power-on state, the BMS of each car determines that the handshake identification with the charging server is successful after receiving the charging parameter message sent by the charging server, and controls the traction circuit of each car to stop supplying power to the car power running module.

In one possible embodiment, the traction circuit includes a traction working branch, which is connected to a traction inverter for inputting the voltage of the car power battery to the traction inverter;

the BMS controls the traction circuit to stop supplying power to the carriage power running module, and comprises:

the BMS disconnects the traction working leg such that the traction circuit is disconnected.

Specifically, the BMS of each car disconnects the traction circuit of each car by controlling the traction contactors of each car to be disconnected.

In another possible implementation manner, the traction circuit includes a traction inverter, and the traction inverter is configured to convert direct current output by the car power battery into alternating current and then input the alternating current to the car power running module;

the BMS controls the traction circuit to stop supplying power to the carriage power running module, and the BMS further comprises:

the BMS controls the traction inverter to be in a cut-off state.

Specifically, the BMS of each car sends a handshake success signal to the traction inverter of each car, and the traction inverter of each car controls its own shut-off wave after receiving the handshake success signal, and at this time, the output power of the traction inverter of each car is zero.

In addition, after the BMSs of all the carriages control the traction circuits of all the carriages to stop supplying power to the power running modules of all the carriages, the train is changed from a high-voltage power-on state to a high-voltage charging mode, namely the traction circuits of all the carriages do not work, and the DC circuits work normally.

Specifically, when the train is in a low-voltage power-on state, the BMS of each car determines that handshake identification with the charging server is successful after receiving the charging parameter message sent by the charging server, and controls the DC loops of the respective cars to be conducted.

In one possible embodiment, the DC circuit includes a DC pre-charging branch, a DC working branch and a DC converter, the DC pre-charging branch and the DC working branch are respectively connected to the DC converter, and are respectively used for inputting the voltage of the car power battery into the DC converter, and the DC converter is used for outputting the voltage of the car power battery after being stepped down to the car low-voltage load;

the BMS controls the DC loop to be conducted, and comprises:

the BMS controls the DC pre-charging branch circuit to be conducted and detects the input voltage of the DC converter;

and under the condition that the input voltage of the DC converter is greater than a second preset voltage threshold value, the BMS controls the DC pre-charging branch circuit to be disconnected and controls the DC working branch circuit to be connected.

Wherein, the second preset voltage threshold value can be 90% of the voltage value of the power battery of the carriage.

In an alternative embodiment, please refer to fig. 4 again, the BMS of each car controls the DC pre-charging contactor KM21 in the DC loop of each car to pull in according to the charging notification instruction, so that the large capacitor at the input end of the DC converter is charged, which causes the input voltage of the DC converter to increase continuously, and at the same time, the BMS of each car receives the input voltage of the DC converter sent by the DC converter in real time, and compares the received input voltage of the DC converter with the second preset voltage threshold, when the input voltage of the DC converter is greater than the second preset voltage threshold, the BMS of each car pulls in the DC contactor KM22 of the DC working branch, and disconnects the DC pre-charging contactor KM21 of the DC pre-charging branch, at this time, the DC loop of each car is in a conducting state, the energy storage battery of each car does not supply power to the low-voltage load of the car any more, and the DC loop of each car supplies power to the low-voltage load of each car.

In another possible embodiment, the traction circuit comprises a traction inverter, and the traction inverter is used for converting direct current output by the carriage power battery into alternating current and then inputting the alternating current to the carriage power running module;

the method further comprises the following steps:

and the BMS controls the traction loop to be conducted and controls the traction inverter to be in a cut-off state.

Further, the traction circuit comprises a traction pre-charging branch, a traction working branch and the traction inverter, wherein the traction pre-charging branch and the traction working branch are respectively connected with the traction inverter and are respectively used for inputting the voltage of the compartment power battery into the traction inverter;

the BMS controls the traction circuit to be conducted, including:

the BMS controls the traction pre-charging branch circuit to be conducted and detects the input voltage of the traction inverter;

and under the condition that the input voltage of the traction inverter is greater than a first preset voltage threshold value, the BMS controls the traction pre-charging branch circuit to be disconnected and controls the traction working branch circuit to be connected.

Wherein, the first preset voltage threshold value may be 90% of the voltage value of the power battery of the vehicle cabin.

In an alternative embodiment, please refer to fig. 4 again, after the BMS of each car receives the charging notification instruction, the BMS of each car controls the DC pre-charging contactor KM21 in the DC loop of each car to pull in according to the charging notification instruction, so that the large capacitor at the input end of the DC converter is charged, and the input voltage of the DC converter is increased continuously, meanwhile, the BMS of each car receives the input voltage of the DC converter sent by the DC converter in real time, and compares the received input voltage of the DC converter with a second preset voltage threshold, when the input voltage of the DC converter is greater than the second preset voltage threshold, the BMS of each car pulls in the DC contactor KM22 of the DC working branch, and disconnects the DC pre-charging contactor KM21 of the DC pre-charging branch, at this time, the DC loop of each car is in a conducting state, the energy storage battery of each car does not supply power to the low-voltage load of each car, and the DC loop of each car supplies power to the low-voltage load of each car. And the BMSs of the carriages control the traction pre-charging contactors KM21 in the traction loops of the carriages to be attracted, so that a large capacitor at the input end of the traction inverter is charged, the input voltage of the traction inverter is increased continuously, meanwhile, the BMSs of the carriages detect the input voltage of the traction inverter sent by the traction inverter in real time, the received input voltage of the traction inverter is compared with a first preset voltage threshold, when the input voltage of the traction inverter is greater than the first preset voltage threshold, the BMSs of the carriages disconnect the traction pre-charging contactors KM11 of the traction pre-charging branch and attract the traction contactors KM12 of the traction working branch, at the moment, the traction loops of the carriages are in a conducting state, the BMSs of the carriages send handshake success signals to the traction inverters of the carriages, the traction inverters control the turn-off of the carriages according to the handshake success signals, at the moment, the output power of the traction inverters of the carriages is zero, and the power batteries of the carriages do not supply power running modules of the carriages.

After the BMSs of all the cars control the DC circuits of all the cars to be conducted, the train is changed from a low-voltage power-on state to a low-voltage charging mode, namely, the traction circuits of all the cars of the train are in a disconnected state, and the DC circuits are in a conducting state.

S105, the vehicle controller sends a charging request message to the BMS.

Specifically, the vehicle controller sends a charging request message to the BMS of each car upon receiving a charging signal sent by a charger by turning on a charging knob. And the charging request message is used for controlling the corresponding charging bow to fall.

And S106, after confirming that the charging preparation is completed, the BMS sends a charging request message to the charging station.

Specifically, when the train is in a high-voltage power-on state, the BMSs of all the carriages send a charging request message to a charging server under the condition that the BMSs determine that the traction loops of all the carriages do not supply power to the power running modules of all the carriages any more, and the charging server sends the charging request message to a charging controller after receiving the charging request message; and when the train is in a low-voltage power-on state, the BMS of each carriage sends a charging request message to the charging server under the condition of confirming the conduction of the DC loop, and the charging server sends the charging request message to the charging controller after receiving the charging request message.

In the embodiment of the application, under the condition that the train is in a high-voltage power-on state, the BMS of each carriage carries out handshake identification with the charging station when receiving handshake messages sent by the charging station according to received charging notification instructions, and under the condition that the BMS of each carriage confirms that the handshake identification with the charging station is successful, the traction circuit of each carriage is controlled not to supply power to the power running module of each carriage.

Fig. 6 is a schematic flow chart illustrating a control method of a train charging system according to an embodiment of the present disclosure. As shown in fig. 6, this method embodiment includes the steps of:

s201, the vehicle controller sends a charge notification instruction to the BMS.

S202, the charging station sends a handshake message to the BMS.

And S203, the BMS performs handshake identification with the charging station when receiving the handshake messages sent by the charging station according to the charging notification instruction.

And S204, the BMS performs charging preparation under the condition that the BMS confirms that the handshake identification with the charging station is successful.

S205, the vehicle controller sends a charging request message to the BMS.

And S206, after confirming that the charging preparation is completed, the BMS sends a charging request message to the charging station.

Here, the specific implementation manner of steps S201 to S205 may refer to the description of steps S101 to S106 in the embodiment corresponding to fig. 3, and is not described herein again.

And S207, the charging station controls the corresponding charging bow to fall according to the charging request message, and detects the connection state between the charging bow and the corresponding carriage current collector after the charging bow falls to the position.

Referring to fig. 2 again, as shown in fig. 2, the charging station further includes a charging bow controller and a charging connection detection module, wherein the charging connection detection module includes a charging connection detection module 1, \8230; the charging bow controller and the charging connection detection module are connected with the charging controller, and the charging bow controller is connected with the charging bow.

In an optional embodiment, taking the first car as an example, after receiving the charging request message, the charging controller sends a pantograph lowering instruction to the charging pantograph controller, the charging pantograph controller controls the charging pantograph corresponding to the first car to lower according to the pantograph lowering instruction, receives the stress of an electrode sent by a pressure sensor installed on the electrode of the charging pantograph, and sends a start detection instruction to a charging connection detection module corresponding to the first car when the received stress of the electrode reaches a preset stress value, and the charging connection detection module detects the connection state between the charging pantograph and the car current collector of the first car according to the start detection instruction and sends the connection state to the charging controller.

And S208, when the connection state between the charging bow and the corresponding compartment current collector is normal connection, the charging station and the BMS carry out charging parameter configuration.

In an optional embodiment, taking the first car as an example, when the charging controller receives that the connection state between the charging bow and the corresponding car current collector is a normal connection, sending a message that the connection between the charging bow and the corresponding car current collector is normal to the charging server, after receiving the message that the connection between the charging bow and the corresponding car current collector is normal, the charging server and the BMS entering a charging parameter configuration stage, the charging server sending a maximum output capacity message of the charger to the BMS, the BMS judging whether charging can be performed according to the received maximum output capacity message of the charger, if charging can be performed, sending a charging ready message to the charging server, the charging server sending the charging ready message to the BMS after receiving the charging ready message, and at this time, ending the charging configuration stage. In addition, when the charging controller receives that the connection state of the charging bow and the corresponding compartment current collector is normal connection, a stop detection instruction is sent to the charging connection detection module, and the charging connection detection module stops detecting the connection state between the charging bow and the corresponding compartment current collector after receiving the stop detection instruction.

And S209, after the configuration of the charging parameters is finished, the charging station charges the train through the charging arch according to the configuration result of the charging parameters.

Specifically, after the charging parameter configuration stage is finished, the charging station charges the power batteries of each compartment through each charging arch and the compartment current collectors corresponding to the charging arches.

In the embodiment of the application, under the condition that the train is in a low-voltage power-on state, the BMS of each carriage conducts handshake identification with the charging station when receiving a handshake message sent by the charging station according to a received charging notification instruction, and controls the DC loops of the carriages to be conducted under the condition that the BMS of each carriage confirms that the handshake identification with the charging station is successful.

The terms "first," "second," "third," and "fourth," etc. in the description and claims of this application and in the accompanying drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

In the present application, "a and/or B" means one of the following cases: a, B, A and B. "\8230; \ 8230;" at least one of which means any combination of the listed items or any number of the listed items, for example, "at least one of A, B, and C" means one of the following: any one of seven cases of A, B, C, A and B, B and C, A, B and C.

It will be understood by those skilled in the art that all or part of the processes of the methods of the embodiments described above can be implemented by a computer program, which can be stored in a computer-readable storage medium, and when executed, can include the processes of the embodiments of the methods described above. The storage medium may be a magnetic disk, an optical disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), or the like.

The method and the related apparatus provided by the embodiments of the present application are described with reference to the flowchart and/or the structural diagram of the method provided by the embodiments of the present application, and each flow and/or block of the flowchart and/or the structural diagram of the method, and the combination of the flow and/or block in the flowchart and/or the block diagram can be specifically implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block or blocks of the block diagram. These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block or blocks of the block diagram. These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

The above disclosure is only for the purpose of illustrating the preferred embodiments of the present application and is not to be construed as limiting the scope of the present application, so that the present application is not limited thereto, and all equivalent variations and modifications can be made to the present application.

Claims

1. A train, the train includes vehicle controller and at least one carriage, its characterized in that, each carriage in at least one carriage includes BMS battery management system, DC direct current return circuit, traction circuit and carriage communication module, the DC direct current return circuit is used for inputing carriage low pressure load after stepping down carriage power battery's voltage, traction circuit is used for inputing carriage power driving module after will carriage power battery's voltage contravariant, wherein:

the BMS is used for carrying out charging preparation under the condition that the handshake identification with the charging station is successful;

the charging preparation comprises the steps of controlling the traction loop to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC direct-current loop to be conducted when the train is in a low-voltage power-on state, wherein the DC direct-current loop and the traction loop are both in a conducting state when the train is in the high-voltage power-on state, and the DC direct-current loop and the traction loop are both in a disconnecting state when the train is in the low-voltage power-on state;

2. The train of claim 1 wherein the traction circuit includes a traction work leg coupled to a traction inverter for inputting the voltage of the car power battery to the traction inverter;

the BMS is used for disconnecting the traction working branch when the train is in a high-voltage power-on state, so that the traction loop is disconnected.

3. The train of claim 1, wherein the traction circuit comprises a traction inverter, and the traction inverter is used for converting direct current output by the carriage power battery into alternating current and inputting the alternating current to the carriage power driving module;

the BMS is also used for controlling the traction inverter to be in a cut-off state when the train is in a high-voltage power-on state.

4. The train of claim 1, wherein the traction circuit comprises a traction inverter, and the traction inverter is used for converting direct current output by the compartment power battery into alternating current and then inputting the alternating current to the compartment power driving module;

and the BMS is also used for controlling the traction loop to be conducted and controlling the traction inverter to be in a cut-off state when the train is in a low-voltage power-on state.

5. The train according to claim 4, wherein the traction circuit further comprises a traction pre-charging branch and a traction working branch, the traction pre-charging branch and the traction working branch are respectively connected with the traction inverter and are respectively used for inputting the voltage of the compartment power battery into the traction inverter;

the BMS is used for controlling the conduction of the traction pre-charging branch and detecting the input voltage of the traction inverter;

and the BMS is used for controlling the traction pre-charging branch circuit to be disconnected and controlling the traction working branch circuit to be connected when the input voltage of the traction inverter is greater than a first preset voltage threshold value.

6. The train according to claim 1, wherein the DC direct-current circuit comprises a DC pre-charging branch circuit, a DC working branch circuit and a DC converter, the DC pre-charging branch circuit and the DC working branch circuit are respectively connected to the DC converters and are respectively used for inputting the voltage of the car power battery into the DC converter, and the DC converter is used for reducing the voltage of the car power battery and inputting the reduced voltage into the car low-voltage load;

the BMS is used for controlling the conduction of the DC pre-charging branch circuit and detecting the input voltage of the DC converter when the train is in a low-voltage power-on state;

and the BMS is used for controlling the disconnection of the DC pre-charging branch circuit and controlling the conduction of the DC working branch circuit when the input voltage of the DC converter is greater than a second preset voltage threshold value.

7. The train according to claim 1, wherein the vehicle controller is configured to send the charging notification instruction to the BMS upon confirming that a current state of the train is a stationary state.

8. The control method of the train is characterized in that the train comprises a train controller and at least one compartment, each compartment in the at least one compartment comprises a BMS battery management system, a DC direct-current loop, a traction loop and a compartment communication module, wherein the DC direct-current loop is used for reducing the voltage of a compartment power battery and then inputting the voltage into a compartment low-voltage load, and the traction loop is used for inverting the voltage of the compartment power battery and then inputting the voltage into a compartment power running module;

the method comprises the following steps:

in case of confirming that the handshake recognition with the charging station is successful, the BMS performs charging preparation;

the charging preparation comprises the steps of controlling the traction circuit to stop supplying power to the compartment power running module when the train is in a high-voltage power-on state, or controlling the DC direct-current circuit to be conducted when the train is in a low-voltage power-on state, wherein the DC direct-current circuit and the traction circuit are both in a conducting state when the train is in the high-voltage power-on state, and the DC direct-current circuit and the traction circuit are both in a disconnecting state when the train is in the low-voltage power-on state;

9. The utility model provides a train charging system, its characterized in that, train charging system includes train and charging station, the train includes vehicle controller and an at least carriage, each carriage in an at least carriage includes BMS battery management system, DC direct current return circuit, traction circuit, carriage communication module and carriage current collector, the DC direct current return circuit is used for inputing carriage low voltage load after stepping down carriage power battery's voltage, traction circuit is used for with input carriage power module of traveling after carriage power battery's voltage contravariant, the charging station includes at least one charging bow, wherein:

the BMS is connected with the compartment communication module and used for performing handshake identification with the charging station through the compartment communication module when receiving a handshake message sent by the charging station according to the charging notification instruction;

the charging station is used for sending a handshake message to the BMS;

10. The control method of the train charging system is characterized in that the train charging system comprises a train and a charging station, the train comprises a vehicle controller and at least one carriage, each carriage in the at least one carriage comprises a BMS battery management system, a DC (direct current) circuit, a traction circuit, a carriage communication module and a carriage current collector, the DC circuit is used for inputting the voltage of a carriage power battery into a carriage low-voltage load after reducing the voltage, the traction circuit is used for inputting the voltage of the carriage power battery into a carriage power running module after inverting the voltage, and the charging station comprises at least one charging bow;

the method comprises the following steps:

the charging station sends a handshake message to the BMS;

and the charging station charges the train under the condition that the charging bow is confirmed to be normally connected with the corresponding carriage current collector.