Electrified railway brake energy recovery control distribution system and method

Abstract

The application relates to an electrified railway brake energy recovery control distribution system and method, wherein the method comprises the following steps: S1: collecting electrical quantities of left and right power supply arms of a traction substation, calculating left arm instantaneous active power and right arm instantaneous active power of the traction substation based on the electrical quantities, and obtaining power of the traction substation; S2: judging a system working mode according to a power product of the power of the traction substation, when the power product P1*P2<0, the brake energy recovery control distribution system enters a power regulator adjustment mode; when the power product P1*P2>=0, the power of the first and second traction substations is compared with the charge-discharge threshold value P_thr of the respective energy storage systems, when the power is greater than the threshold value, the brake energy recovery control distribution system enters the charge-discharge mode of the energy storage system. Through the application, the technical problem of low utilization rate of regenerative braking energy is solved, effective coordinated control of on-demand transfer, storage and release of regenerative braking energy is realized, and efficient utilization of regenerative braking energy of the traction substation is realized.

Description

Technical Field

[0001] This invention relates to the field of electrified railway technology, and in particular to an electrified railway braking energy recovery control and distribution system and method. Background Technology

[0002] Electrified railways employ a single-phase segmented power supply method. To prevent phase-to-phase short circuits or circulating currents, the traction power supply system uses phase separation between substations. The two-sided power supply arms of each substation are independent and not interconnected, preventing the mutual utilization of regenerative braking energy between substations. Current power regulators can only recover and utilize regenerative braking energy when one traction substation is in braking mode and the other is in traction mode. Furthermore, energy storage systems can only absorb and utilize braking energy by judging the electrical quantity data of the left and right power supply arms.

[0003] Existing regenerative energy recovery technologies include solutions that simultaneously install railway-like power regulators in the substations and energy storage systems in the traction substations, effectively improving the utilization rate of regenerative braking energy, such as CN112406636B. However, this solution involves three traction substations, utilizing three railway-like power regulators and one energy storage system. The energy flow judgment logic is complex, and the computational load is enormous, consuming significant memory. Furthermore, considering the considerable distance between traction substations, energy losses are likely to occur during transmission. This invention proposes a braking energy recovery control and distribution system and method involving two traction substations. The system uses a central processing unit to connect the systems, achieving collaborative management of the braking energy backflow problem within the traction substations. Through a refined collaborative distribution method, the system effectively coordinates and controls the on-demand transfer, storage, and release of regenerative braking energy, thereby improving the utilization rate of regenerative braking energy. Summary of the Invention

[0004] To address the aforementioned technical challenges, this invention discloses a control and distribution system and method for regenerative braking energy in electrified railways. It employs a power regulator as the primary mechanism and an energy storage system as a secondary mechanism to rationally regulate the recovery and reuse of braking energy from two traction substations. Through a sophisticated collaborative distribution method, the power distribution mode under real-time operating conditions is determined, effectively coordinating and controlling the on-demand transfer, storage, and release of regenerative braking energy. This addresses at least the issues of regulating and storing regenerative braking energy, rationally distributing braking energy, and improving the utilization rate of regenerative braking energy.

[0005] In a first aspect, embodiments of this application provide an electrified railway braking energy recovery control and distribution system, including a first traction substation, a second traction substation, and a sectioning station between the first and second traction substations; the first traction substation is equipped with a first energy storage system, and the second traction substation is equipped with a second energy storage system; the sectioning station between the first and second traction substations is equipped with a power regulator, and the braking energy recovery control and distribution system further includes: an information acquisition module and a central processing unit;

[0006] Both the first traction substation and the first traction substation are equipped with information acquisition modules, which include:

[0007] Information acquisition unit: Collects electrical quantities of the left and right power supply arms of the traction substation.

[0008] Power calculation unit: Based on the electrical quantities of the left and right power supply arms of the traction substation, calculate the instantaneous active power of the left and right arms of the traction substation, and obtain the power of the traction substation.

[0009] in:

[0010] P1=P11+P12; P2=P21+P22;

[0011] P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation.

[0012] The partition is equipped with a central processing unit, which includes an energy management module and a logic judgment unit.

[0013] The logic judgment unit is configured to: determine the system operating mode based on the power product of the substation power; when the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator adjustment mode, the power regulator operates, and the first and second energy storage systems are in standby mode; when the power product P1*P2≥0, the power of the first and second traction substations is compared with the charging and discharging threshold P_thr of their respective energy storage systems; when the power is greater than the threshold, the energy storage system of the traction substation on the side with the power greater than the threshold is started, and the energy storage system enters the charging and discharging mode, while the power regulator is in standby mode; when the power is less than or equal to the threshold, the energy storage system of the traction substation on the side with the power less than or equal to the threshold is controlled to be in standby mode, and the power regulator is in standby mode.

[0014] Furthermore, the central processing unit also includes:

[0015] Data processing unit: Communicates with information acquisition unit and power calculation unit, and determines the power distribution mode of braking energy recovery control and distribution system based on the electrical quantities of the left and right power supply arms of the traction substation collected by information acquisition unit and the instantaneous active power of the left and right arms calculated by power calculation unit.

[0016] Control unit: Communicates with data processing unit to obtain power distribution mode data, sends power control commands according to power distribution mode, and controls the operation of power regulator and first and second energy storage system equipment.

[0017] Furthermore, the central processing unit is configured to: predict the operating time of the regenerative braking energy recovery control and distribution system in the charging and discharging modes of the first and second energy storage systems and the power regulator mode, and set the system start-up time threshold and the start-up threshold of regenerative braking energy recovery based on the predicted operating time.

[0018] Furthermore, the energy management module is configured to analyze real-time data from the electrified railway traction substation throughout the day and, in conjunction with the train operation diagram, fit the braking energy recovery time interval.

[0019] The central processing unit also includes:

[0020] Monitoring module: Based on the braking energy recovery time interval, it performs information monitoring and energy scheduling for the power regulator, the first and second energy storage systems.

[0021] Secondly, embodiments of this application also provide a method for controlling and distributing brake energy recovery in electrified railways, comprising:

[0022] S1: Information collection steps: Collect the electrical quantities of the left and right power supply arms of each traction substation, calculate the instantaneous active power of the left and right arms of each traction substation based on the electrical quantities of the left and right power supply arms of each traction substation, and calculate the power of each traction substation.

[0023] in:

[0024] P1=P11+P12; P2=P21+P22;

[0025] P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation.

[0026] S2: Logical judgment step: determining the working mode of the system according to the power product of the substation power. When the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator adjustment mode, the power regulator operates, and the first and second energy storage systems are in standby; when the power product P1*P2≥0, comparing the power of the first and second traction substations with the charge and discharge thresholds P_thr of their respective energy storage systems separately. When the power is greater than the threshold, starting the energy storage system of the traction substation on the side where the power is greater than the threshold, entering the charge and discharge mode of the energy storage system, and the power regulator is in standby; when the power is less than or equal to the threshold, controlling the energy storage system of the traction substation on the side where the power is less than or equal to the threshold to be in standby, and the power regulator is in standby.

[0027] Further, step S2 further comprises:

[0028] S21: Data analysis and processing step: determining the power distribution mode of the braking energy recovery control and distribution system according to the collected electrical parameters of the left power supply arm and the right power supply arm of the traction substation and the calculated instantaneous active power of the left arm and the instantaneous active power of the right arm;

[0029] S22: Control step: acquiring power distribution mode data, sending a power control instruction according to the power distribution mode, and controlling the operation of the power regulator and the first and second energy storage system devices.

[0030] Further, step S21 comprises the power regulator adjustment mode:

[0031] judging the power transfer between traction substations: when the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero, the first traction substation feeds power back through braking, the second traction substation consumes power for traction, and active power is transferred from the first traction substation to the second traction substation; if |P1|<P2, the active power is |P1|, and if |P1|>P2, the active power is P2;

[0032] when the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero, the first traction substation consumes power for traction, the second traction substation feeds power back through braking, and active power is transferred from the second traction substation to the first traction substation; if |P2|<P1, the active power is -|P2|, and if |P2|<P1, the active power is -P1.

[0033] Further, step S21 comprises the charge and discharge mode of the energy storage system:

[0034] carrying out the following judgment on the first and second traction substations one by one: when the power of a traction substation is less than zero, reading the SOC capacity of the supercapacitor in the information of the respective energy storage system, and if the SOC capacity of the energy storage system of the traction substation is less than the upper capacity limit, the energy storage system of the traction substation is charged;

[0035] Determining whether the instantaneous active power of the left arm of the traction substation is less than zero; if yes, the energy storage system enters the charging mode for the left power supply arm of the traction substation where it is located; otherwise, the energy storage system enters the charging mode for the right power supply arm of the traction substation where it is located;

[0036] When the power of the traction substation is greater than zero, reading the SOC capacity of the supercapacitor from the information of the respective energy storage system; if the SOC capacity of the energy storage system of the traction substation is greater than the lower capacity limit, the energy storage system of the traction substation discharges;

[0037] Determining whether the instantaneous active power of the left arm of the traction substation is greater than zero; if yes, the energy storage system of the traction substation enters the discharge mode for the left power supply arm of the traction substation; otherwise, the energy storage system of the traction substation enters the discharge mode for the right power supply arm of the traction substation. Further, step S22 comprises:

[0038] Power regulator regulation mode:

[0039] When the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero, if |P1|<P2, the central processing host controls the active power |P1| to be transferred from the first traction substation to the second traction substation; if |P1|>P2, the central processing host controls the active power P2 to be transferred from the first traction substation to the second traction substation;

[0040] When the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero, if |P2|<P1, the central processing host controls the active power of -|P2| to be transferred from the second traction substation to the first traction substation|; if |P2|<P1, the central processing host controls the active power of -P1 to be transferred from the second traction substation to the first traction substation;

[0041] Charging and discharging modes of energy storage system:

[0042] When the power of the traction substation is less than zero and the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system of the traction substation to enter the charging mode for the left power supply arm of the traction substation where it is located; when the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system to enter the charging mode for the right power supply arm of the traction substation where it is located, and after being fully charged, the energy storage system enters a standby state to wait for a control instruction;

[0043] When the power of the traction substation is greater than zero and the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system of the traction substation to enter the discharge mode for the left power supply arm of the traction substation where it is located; when the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system to enter the discharge mode for the right power supply arm of the traction substation where it is located, and after being fully discharged, the energy storage system enters a standby state to wait for a control instruction.

[0044] Furthermore, the braking energy recovery control and distribution method also includes: predicting the operating time of the braking energy recovery control and distribution system in the charging and discharging modes of the first and second energy storage systems and the power regulator mode, and setting the system start-up time threshold and the start-up threshold of regenerative braking energy recovery based on the predicted operating time.

[0045] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0046] (1) The electrified railway braking energy recovery control and distribution system and method provided by the present invention adopts the following approach: energy storage systems are installed in two adjacent traction substations at the same time, and railway power regulators are installed in the substations. The central processing host completes the connection and control of the system. Through a perfect collaborative distribution method, the power distribution mode under the corresponding working conditions is determined. The system operates in the power regulator adjustment mode to regulate the transfer of power between the two traction substations. When operating in the energy storage system working mode, braking energy is stored or auxiliary traction power is used between the power supply arms in the traction substation. Braking energy is rationally distributed, and regenerative braking energy is effectively coordinated and controlled to be transferred, stored and released as needed, so as to realize the efficient utilization of regenerative braking energy in the traction substation.

[0047] (2) The central processing host analyzes the impact of data such as train load and speed on the electrical quantity data of the electrified railway traction substation, and combines the train operation diagram to fit the braking energy recovery time interval. During this interval, the system works in braking energy recovery mode. During other time intervals, the central processing host controls the power regulator of the substation to not work. When the difference in traction power between the two arms of the traction substation reaches the power fusion start threshold, the control energy storage system can perform power fusion to solve problems such as negative sequence of the power grid and reactive power compensation in the traction substation.

[0048] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0049] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0050] Figure 1 This is a schematic diagram of the structure of an electrified railway regenerative energy recovery system provided in an embodiment of this application;

[0051] Figure 2 This is a functional block diagram of a central processing unit provided in an embodiment of this application;

[0052] Figure 3This is a schematic diagram of information interaction in an electrified railway braking energy recovery control and distribution system provided in an embodiment of this application;

[0053] Figure 4 This is a flowchart of a control method for a brake energy recovery control and distribution system for electrified railways, provided in an embodiment of this application.

[0054] Figure 5 This is a flowchart of a control method for a brake energy recovery control and distribution system for electrified railways, provided in another embodiment of this application.

[0055] Figure 6 This is a schematic diagram of the energy flow control of the energy storage system in an electrified railway braking energy recovery control and distribution system provided in an embodiment of this application. Detailed Implementation

[0056] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0057] To address the technical problems of low regenerative braking energy utilization in existing traction substations due to the return of braking energy, this invention provides an electrified railway braking energy recovery control and distribution system and method. This system collects and calculates power information through an information acquisition module and dynamically allocates regenerative braking energy through a central processing unit. It effectively coordinates and controls the on-demand transfer, storage, and release of regenerative braking energy, achieving efficient utilization of regenerative braking energy in traction substations.

[0058] The technical solution of the present invention will be described in detail below with reference to specific embodiments and accompanying drawings.

[0059] This invention provides an electrified railway braking energy recovery control and distribution system, including a first traction substation, a second traction substation, and a sectioning station between the first and second traction substations; the first traction substation is equipped with a first energy storage system, the second traction substation is equipped with a second energy storage system, and the sectioning station between the first and second traction substations is equipped with a power regulator.

[0060] refer to Figure 1The AC electrified railway energy storage system is installed between the two power supply arms of the traction substation. One end of the AC switchgear is connected to the 27.5kV AC power supply arm of the traction substation, and the other end is connected to the primary side of the step-down transformer. The secondary side of the step-down transformer is connected to a back-to-back four-phase converter. The DC output of the back-to-back four-phase converter is connected to one end of a multi-level bidirectional DC / DC converter, and the other end of the multi-level bidirectional DC / DC converter is connected to a supercapacitor system. Based on the traction load characteristics, this system enables the storage and release of regenerative braking energy. The railway power regulator is installed between the power supply arms at both ends of the electrical phase separation. One end of the AC switchgear is connected to the 27.5kV AC power supply arm of the section substation, and the other end is connected to the primary side of the step-down transformer. The secondary side of the step-down transformer is connected to a back-to-back four-phase converter, enabling the transfer and utilization of braking energy from both sides of the traction substation.

[0061] The regenerative braking control and distribution system also includes: an information acquisition module and a central processing unit;

[0062] Both the first traction substation and the first traction substation are equipped with information acquisition modules, which include:

[0063] Information acquisition unit: collects the electrical quantities of the left and right power supply arms of the traction substation; that is, the information acquisition unit of the first traction substation collects the electrical quantities of the left and right power supply arms of the first traction substation, and the information acquisition unit of the second traction substation collects the electrical quantities of the left and right power supply arms of the second traction substation.

[0064] Power calculation unit: Based on the electrical quantities of the left and right power supply arms of the traction substation, calculate the instantaneous active power of the left and right arms of the traction substation, and obtain the power of the traction substation.

[0065] That is, the power calculation unit of the first traction substation calculates the instantaneous active power of the left and right arms of the first traction substation based on the electrical quantities of the left and right power supply arms of the first traction substation, and calculates the power of the first traction substation based on the instantaneous active power of the left and right arms of the first traction substation; the power calculation unit of the second traction substation calculates the instantaneous active power of the left and right arms of the second traction substation based on the electrical quantities of the left and right power supply arms of the second traction substation, and calculates the power of the second traction substation based on the instantaneous active power of the left and right arms of the second traction substation.

[0066] in:

[0067] P1=P11+P12; P2=P21+P22;

[0068] P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation.

[0069] The partition is equipped with a central processing unit, which includes an energy management module and a logic judgment unit.

[0070] The logic judgment unit is configured to: determine the system operating mode based on the power product of the substation power. The system operating mode is divided into power regulator adjustment mode and energy storage system charging / discharging mode. When the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator adjustment mode, the power regulator is working, and the first and second energy storage systems are in standby mode. When the power product P1*P2≥0, the power of the first and second traction substations is compared with the charging / discharging threshold P_thr of their respective energy storage systems. When the power product is greater than the threshold, the energy storage system of the traction substation on the side with the power greater than the threshold is started and enters the energy storage system charging / discharging mode, and the power regulator is in standby mode. When the power product is less than or equal to the threshold, the energy storage system of the traction substation on the side with the power less than or equal to the threshold is controlled to be in standby mode, and the power regulator is in standby mode.

[0071] That is, when the power product P1*P2≥0, the power P1 of the first traction substation is compared with the charging / discharging threshold P_thr1 of the first energy storage system. When P1>P_thr1, the first energy storage system starts working and charges or discharges according to the actual operating conditions. When P1<P_thr1, the first energy storage system is in standby mode. Similarly, the power P2 of the second traction substation is compared with the charging / discharging threshold P_thr2 of the second energy storage system. When P2>P_thr2, the second energy storage system starts working and charges or discharges according to the actual operating conditions. When P2<P_thr2, the second energy storage system is in standby mode. P_thr1 and P_thr2 may be equal or unequal.

[0072] In this embodiment, the central processing unit further includes:

[0073] Data processing unit: Communicates with information acquisition unit and power calculation unit, and determines the power distribution mode of braking energy recovery control and distribution system based on the electrical quantities of the left and right power supply arms of the traction substation collected by information acquisition unit and the instantaneous active power of the left and right arms calculated by power calculation unit.

[0074] Control unit: Communicates with data processing unit to obtain power distribution mode data, sends power control commands according to power distribution mode, and controls the operation of power regulator and first and second energy storage system equipment.

[0075] In practical applications, refer to Figure 2-3 The central processing unit also includes a communication unit that establishes information exchange with the information acquisition modules of the first and second traction substations, the first and second energy storage systems, and the power regulator. This unit transmits power information and issues corresponding power control commands according to the power distribution mode, controlling the system to perform dynamic power distribution and realize the allocation of regenerative braking energy. The braking energy recovery control and distribution system collects electrical quantity information from the two traction substations, energy storage system information, and power regulator information and reports it to the central processing unit in real time. The central processing unit coordinates and controls the various units in the system based on the feedback information, improving the utilization rate of regenerative braking energy recovery in the electrified railway regenerative braking energy recovery system.

[0076] Continue to refer to Figure 2-3 The central processing unit also includes a monitoring unit, which has functions such as real-time data display, historical data storage, configuration editing and screen display. The communication unit interacts with the information acquisition module, energy storage system and power regulator via fiber optic or 5G wireless communication.

[0077] In this embodiment, the central processing unit is configured to: predict the operating time of the regenerative braking energy recovery control and distribution system in the charging and discharging modes of the first and second energy storage systems and the power regulator mode, and set the system start-up time threshold and the start-up threshold of regenerative braking energy recovery based on the predicted operating time.

[0078] In practical applications, in order to ensure the operational stability of each converter in power regulator and energy storage system modes, the impact of vehicle load and speed on the electrical quantity information of traction substation is analyzed by combining the train operation diagram and the electrical quantity information of traction substation in the past. The operating time of the equipment in energy storage system charging and discharging mode and power regulator mode is predicted, and time thresholds and regenerative braking energy recovery start thresholds are set. When the time threshold and start threshold are reached, the logic judgment mode is entered and power commands are issued.

[0079] In this embodiment, the energy management module is configured to analyze real-time data from the electrified railway traction substation throughout the day and, in conjunction with the train operation diagram, fit the braking energy recovery time interval.

[0080] The central processing unit also includes:

[0081] Monitoring module: Based on the braking energy recovery time interval, it performs information monitoring and energy scheduling for the power regulator, the first and second energy storage systems.

[0082] In practical applications, the central processing unit analyzes the impact of data such as train load and speed on the electrical quantities of the traction substation of electrified railways, and combines this with the train operation diagram to fit the braking energy recovery time interval. During this interval, the system operates in braking energy recovery mode. In other time intervals, the central processing unit controls the substation power regulator to not operate. When the difference in traction power between the two arms of the traction substation reaches the power fusion start threshold, the energy storage system can perform power fusion to address issues such as negative sequence and reactive power compensation in the traction substation grid.

[0083] This embodiment also provides a method for controlling and distributing brake energy recovery in electrified railways. Figure 4-6 This is a flowchart of a braking energy recovery control and distribution method for electrified railways according to an embodiment of this application.

[0084] The braking condition of the traction substation is defined as negative, and the traction condition as positive. The braking energy recovery control and distribution method includes the following steps:

[0085] S1: Information collection steps: Collect the electrical quantities of the left and right power supply arms of the two traction substations. Based on the electrical quantities of the left and right power supply arms of each traction substation, calculate the instantaneous active power of the left arm and the instantaneous active power of the right arm of each traction substation, and calculate the power of each traction substation.

[0086] in:

[0087] P1=P11+P12; P2=P21+P22;

[0088] P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation.

[0089] S2: Logical Judgment Steps: Determine the system operating mode based on the power product of the substation power. When the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator adjustment mode, the power regulator operates, and the first and second energy storage systems are in standby mode. When the power product P1*P2≥0, compare the power of the first and second traction substations with their respective energy storage system charging and discharging thresholds P_thr. When the power is greater than the threshold, start the energy storage system of the traction substation on the side with the power greater than the threshold, enter the energy storage system charging and discharging mode, and the power regulator is in standby mode. When the power is less than or equal to the threshold, control the energy storage system of the traction substation on the side with the power less than or equal to the threshold to be in standby mode, and the power regulator is in standby mode.

[0090] S21: Data analysis and processing step: determining the power distribution mode of the braking energy recovery control and distribution system according to the collected electrical parameters of the left power supply arm and the right power supply arm of the traction substation, and the calculated instantaneous active power of the left arm and the instantaneous active power of the right arm;

[0091] In some embodiments, with reference to Figure 1 , Figure 5 , step S21 further comprises a power distribution method in power regulator regulation mode as follows:

[0092] S2101: Power regulator regulation mode:

[0093] Determine the transfer direction and transfer power value of active power between two traction substations according to the positive and negative of the power values of the first and second traction substations.

[0094] Judging the power transfer between traction substations: when the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero, the first traction substation returns power through braking, the second traction substation consumes power for traction, and active power is transferred from the first traction substation to the second traction substation; if |P1|<P2, the active power is |P1|; if |P1|>P2, the active power is P2;

[0095] When the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero, the first traction substation consumes power for traction, the second traction substation returns power through braking, and active power is transferred from the second traction substation to the first traction substation; if |P2|<P1, the active power is -|P2|, and if |P2|<P1, the active power is -P1.

[0096] With further reference to Figure 1 , Figure 5 , step S21 further comprises a power distribution method for charging and discharging modes of the energy storage system as follows:

[0097] S2102: comprising charging and discharging modes of the energy storage system:

[0098] Determine the specific working mode of the energy storage system during active power transfer between the power supply arm and the energy storage system according to the positive and negative of the instantaneous power values of the left and right power supply arms in the first traction substation.

[0099] The following judgment is performed on the first and second traction substations one by one: when the power of a traction substation is less than zero, read the SOC capacity of the supercapacitor in the respective energy storage system information; if the SOC capacity of the energy storage system of the traction substation is less than the upper capacity limit, the energy storage system of the traction substation is charged;

[0100] Determining whether the instantaneous active power of the left arm of a traction substation is less than zero; if yes, the energy storage system of the traction substation enters the charging mode for the left power supply arm of the traction substation; otherwise, the energy storage system of the traction substation enters the charging mode for the right power supply arm of the traction substation;

[0101] When the power of the traction substation is greater than zero, read the SOC capacity of the supercapacitor in respective energy storage system information; if the SOC capacity of the energy storage system of the traction substation is greater than the lower capacity limit, the energy storage system of the traction substation discharges;

[0102] Determining whether the instantaneous active power of the left arm of the traction substation is greater than zero; if yes, the energy storage system of the traction substation enters the discharging mode for the left power supply arm of the traction substation; otherwise, the energy storage system of the traction substation enters the discharging mode for the right power supply arm of the traction substation.

[0103] In specific applications, when the power of the traction substation is less than zero, read the SOC capacity of the supercapacitor in respective energy storage system information; if the condition that the SOC capacity of the energy storage system of the traction substation is less than the upper capacity limit is not satisfied, the energy storage system of the traction substation still remains in standby mode for charging; similarly, when the power of the traction substation is greater than zero, read the SOC capacity of the supercapacitor in respective energy storage system information; if the condition that the SOC capacity of the energy storage system of the traction substation is greater than the lower capacity limit is not satisfied, the energy storage system of the traction substation still remains in standby mode.

[0104] With further reference to Figure 1 , Figure 5 , step S22 further comprises the step of issuing instructions for the regulation mode of the power regulator and the charging and discharging modes of the energy storage system, which is as follows:

[0105] S22: Control step: acquiring power distribution mode data, sending a power control instruction according to the power distribution mode, and controlling the operation of the power regulator and the first and second energy storage system devices.

[0106] Regulation mode of the power regulator:

[0107] When the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero, if |P1|<P2, the central processing host controls active power |P1| to be transferred from the first traction substation to the second traction substation; if |P1|>P2, the central processing host controls active power P2 to be transferred from the first traction substation to the second traction substation;

[0108] When the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero, if |P2|<P1, the central processing host controls active power -|P2| to be transferred from the second traction substation to the first traction substation; if |P2|<P1, the central processing host controls active power -P1 to be transferred from the second traction substation to the first traction substation;

[0109] Charging and discharging modes of energy storage system:

[0110] When the power of the traction substation is less than zero and the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system of the traction substation to enter the charging mode for the left power supply arm of the traction substation; when the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system to enter the charging mode for the right power supply arm of the traction substation, and after being fully charged, the energy storage system enters the standby state to wait for a control command;

[0111] When the power of the traction substation is greater than zero and the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system of the traction substation to enter the discharging mode for the left power supply arm of the traction substation; when the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system to enter the discharging mode for the right power supply arm of the traction substation, and after being fully discharged, the energy storage system enters the standby state to wait for a control command.

[0112] In some illustrative embodiments, with reference to Figure 1 and Figure 5 :

[0113] When the product of powers P1*P2<0, the braking energy recovery control and distribution system enters the power regulator regulation mode, the power regulator operates, the first and second energy storage systems are on standby, and the system performs the following steps:

[0114] When P1<0 and P2>0, if |P1|<P2, the active power is |P1|, and the central processing host issues a control command Ps_ref=|P1|; if |P1|>P2, the active power is P2, and the central processing host issues a control command Ps_ref=P2; at this time, the system operates under working condition 1;

[0115] When P1>0 and P2<0, if P1<|P2|, the active power is P1, and the central processing host issues a control command Ps_ref=P1; if P1>|P2|, the active power is |P2|, and the central processing host issues a control command Ps_ref=|P2|; at this time, the system operates under working condition 2;

[0116] The above active power is the compensation power required for traction power consumption of the traction substation on the side in traction working condition, and Ps_ref is the power control command for the four-quadrant converter of the power regulator.

[0117] With reference to Figure 1 , Figure 5 and Figure 6 :

[0118] If the power product P1*P2≥0, compare the power of the first and second traction substations individually with the charging and discharging threshold P_thr of their respective energy storage systems. If the power exceeds the threshold, start the energy storage system of the traction substation on the side with the higher threshold, enter the energy storage system charging and discharging mode, and put the power regulator into standby mode. Taking the energy storage system of the first traction substation as an example, the following steps are performed:

[0119] When P1 < 0 and the SOC capacity of the supercapacitor in the first energy storage system is less than the upper limit, if P11 < 0, the central processing host sends control commands Pf_ref = Pload, Pr_ref = 0, Psc_ref = Pload to control the energy storage system to enter the charging mode of the left arm of the traction substation. If P11 > 0, the central processing host sends control commands Pf_ref1 = 0, Pr_ref1 = Pload, Psc_ref1 = Pload to control the energy storage system to enter the charging mode of the right arm of the traction substation. After being fully charged, the energy storage system enters standby mode to wait for control commands. At this time, the system is operating under condition 3.

[0120] When P1>0 and the SOC capacity of the supercapacitor in the first energy storage system is greater than the lower limit, when P11>0, the central processing host issues control commands Pf_ref=-Pload, Pr_ref=0, Psc_ref=-Pload to control the energy storage system to enter the discharge mode of the left arm of the traction substation. When P11<0, the central processing host issues control commands Pf_ref=0, Pr_ref=-Pload, Psc_ref=-Pload to control the energy storage system to enter the discharge mode of the right arm of the traction substation. After discharge, the energy storage system enters standby mode to wait for control commands. At this time, the system is operating under condition 4.

[0121] The above Pload is the operating power determined by the time-varying power of the energy storage medium.

[0122] Pf_ref is the power control command for the first converter in the fourth quadrant of the first energy storage system; Pr_ref is the power control command for the first energy storage system in the fourth quadrant.

[0123] The power control command for the second converter, Psc_ref, is the power control command for the DC-DC converter of the first energy storage system. The central processing host issues commands to control each converter to transfer, store, and utilize energy.

[0124] In practical engineering applications, if an energy storage system wants to maintain a constant power charging and discharging mode, it will inevitably generate a large current when the energy storage medium is at its lowest operating voltage. This is suitable for low-power energy storage systems, but in high-power integrated energy storage systems, most charging and discharging are performed with constant current. Limiting the charging and discharging current ensures system stability, resulting in a linear change in the power of the energy storage system. If the central processing host issues a constant rated power command, it will affect the rationality of regenerative braking energy recovery and reuse. To ensure the stability of system energy flow, it is proposed to use the time-varying power of the energy storage medium as the total operating power and to schedule the operating power of the four-quadrant converter in real time to ensure efficient recovery and reuse of regenerative braking energy.

[0125] In some embodiments, the braking energy recovery control and distribution method further includes: predicting the operating time of the braking energy recovery control and distribution system in the charging and discharging modes of the first and second energy storage systems and the power regulator mode, and setting a system start-up time threshold and a regenerative braking energy recovery start-up threshold based on the predicted operating time.

[0126] In some illustrative embodiments, the start-up time threshold is set to 1 minute, and the start-up threshold for regenerative braking energy is set to 1.5 times the rated power. The system remains in standby mode within 1 minute of the start-up time threshold. After 1 minute of the start-up time threshold is reached, and when the instantaneous power value is detected to exceed the start-up threshold, the system enters the logic judgment mode and issues a power command. This can efficiently recover and reuse regenerative braking energy while extending the life of power electronic devices.

[0127] In some embodiments, the braking energy recovery control distribution method further includes:

[0128] S3: Dynamic monitoring steps: Analyze the real-time data of the electrified railway traction substation throughout the day, and combine it with the train operation diagram to fit the braking energy recovery time interval; based on the braking energy recovery time interval, perform information monitoring and energy scheduling of the power regulator, the first and second energy storage systems.

[0129] The present invention discloses an electrified railway braking energy recovery control and distribution system and method, which employs the simultaneous installation of energy storage systems in two adjacent traction substations and railway power regulators in the section substations. The central processing host completes the connection and control of the system. Through a perfected collaborative distribution method, the power distribution mode under real-time operating conditions is determined, and the regenerative braking energy is effectively coordinated and controlled to be transferred, stored and released on demand, thereby realizing the efficient utilization of regenerative braking energy in traction substations.

[0130] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0131] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A braking energy recovery control and distribution system for electrified railways, characterized in that, The braking energy recovery control and distribution system includes a first traction substation, a second traction substation, and a sectioning station between the first and second traction substations; the first traction substation is equipped with a first energy storage system, and the second traction substation is equipped with a second energy storage system; The power regulator configured between the first and second traction substations, and the braking energy recovery control and distribution system also includes: an information acquisition module and a central processing host; Both the first traction substation and the first traction substation are equipped with the aforementioned information acquisition module, which includes: Information acquisition unit: Collects electrical quantities of the left and right power supply arms of the traction substation. Power calculation unit: Based on the electrical quantities of the left and right power supply arms of the traction substation, calculate the instantaneous active power of the left and right arms of the traction substation, and obtain the power of the traction substation. in: P1=P11+P12; P2=P21+P22; P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation. The partition is configured with the central processing unit, which includes an energy management module and a logic judgment unit. The logic judgment unit is configured to: determine the system operating mode based on the power product of the substation power; when the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator adjustment mode, the power regulator operates, and the first and second energy storage systems are in standby mode; when the power product P1*P2≥0, the power of the first and second traction substations is compared with the charging and discharging threshold P_thr of their respective energy storage systems; when the power is greater than the threshold, the energy storage system of the traction substation on the side with the power greater than the threshold is started, and the energy storage system enters the charging and discharging mode, while the power regulator is in standby mode; when the power is less than or equal to the threshold, the energy storage system of the traction substation on the side with the power less than or equal to the threshold is controlled to be in standby mode, and the power regulator is in standby mode.

2. The electrified railway braking energy recovery control and distribution system according to claim 1, characterized in that, The central processing unit also includes: Data processing unit: Communicates with information acquisition unit and power calculation unit, and determines the power distribution mode of braking energy recovery control and distribution system based on the electrical quantities of the left and right power supply arms of the traction substation collected by information acquisition unit and the instantaneous active power of the left and right arms calculated by power calculation unit. Control unit: Communicates with data processing unit to obtain power allocation mode data, sends power control commands according to power allocation mode, and controls the operation of power regulator and first and second energy storage system equipment.

3. The electrified railway braking energy recovery control and distribution system according to claim 1, characterized in that, The central processing unit is configured to: predict the operating time of the braking energy recovery control and distribution system in the charging and discharging modes of the first and second energy storage systems and the power regulator mode, and set the system start-up time threshold and the start-up threshold of regenerative braking energy recovery based on the predicted operating time.

4. The electrified railway braking energy recovery control and distribution system according to any one of claims 1-3, characterized in that, The energy management module is configured to: analyze real-time data of the electrified railway traction substation throughout the day, and fit a braking energy recovery time interval in combination with the train operation diagram; The central processing host further comprises: a monitoring module: configured for information monitoring and energy scheduling of the power regulator, the first energy storage system and the second energy storage system based on the braking energy recovery time interval.

5. A method for controlling and distributing brake energy recovery in electrified railways, implemented based on the brake energy recovery control and distribution system for electrified railways as described in any one of claims 1-4, characterized in that, The method comprises: S1: information collection step: collecting electrical parameters of the left power supply arm and the right power supply arm of each traction substation, calculating the instantaneous active power of the left arm and the instantaneous active power of the right arm of each traction substation based on the collected electrical parameters, and obtaining the power of each traction substation through calculation; wherein: P1=P11+P12;P2=P21+P22; P1 is the power of the first traction substation, P11 is the instantaneous active power of the left arm of the first traction substation, P12 is the instantaneous active power of the left arm of the second traction substation, P2 is the power of the second traction substation, P21 is the instantaneous active power of the right arm of the first traction substation, and P22 is the instantaneous active power of the right arm of the second traction substation; S2: logic judgment step: judging the working mode of the system according to the power product of the substation powers, when the power product P1*P2<0, the braking energy recovery control and distribution system enters the power regulator regulation mode, the power regulator operates, and the first energy storage system and the second energy storage system are in standby; when the power product P1*P2≥0, separately comparing the power of the first traction substation and the power of the second traction substation with the charge-discharge threshold P_thr of the respective energy storage systems, when the power is greater than the threshold, starting the energy storage system of the traction substation on the side where the power is greater than the threshold, entering the charge and discharge mode of the energy storage system, and the power regulator is in standby; when the power is less than or equal to the threshold, controlling the energy storage system of the traction substation on the side where the power is less than or equal to the threshold to be in standby, and the power regulator is in standby.

6. The method for controlling and distributing brake energy recovery in electrified railways according to claim 5, characterized in that, Step S2 further comprises: S21: data analysis and processing step: determining the power distribution mode of the braking energy recovery control and distribution system according to the collected electrical parameters of the left power supply arm and the right power supply arm of the traction substation and the calculated instantaneous active power of the left arm and the instantaneous active power of the right arm; S22: control step: acquiring said power distribution mode data, sending a power control instruction according to the power distribution mode, and controlling the operation of the power regulator, the first energy storage system and the second energy storage system.

7. The method for controlling and distributing brake energy recovery in electrified railways according to claim 6, characterized in that, Step S21 comprises the power regulator regulation mode: judging the power transfer between traction substations: when the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero, the first traction substation returns power via braking, the second traction substation consumes power for traction, and active power is transferred from the first traction substation to the second traction substation; if |P1|<P2, the active power is |P1|; if |P1|>P2, the active power is P2; when the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero, the first traction substation consumes power for traction, the second traction substation returns power via braking, and active power is transferred from the second traction substation to the first traction substation; if |P2|<P1, the active power is -|P2|; if |P2|>P1, the active power is -P1.

8. The method for controlling and distributing brake energy recovery in electrified railways according to claim 6, characterized in that, Step S21 includes charging and discharging modes of an energy storage system: The following judgment is performed on the first and second traction substations one by one: when the power of a traction substation is less than zero, read the SOC capacity of the supercapacitor in the corresponding energy storage system information; if the SOC capacity of the energy storage system of the traction substation is less than the upper capacity limit, the energy storage system of the traction substation is charged; judge whether the instantaneous active power of the left power supply arm of the traction substation is less than zero; if yes, the energy storage system enters the left power supply arm charging mode of the traction substation where it is located; otherwise, the energy storage system enters the right power supply arm charging mode of the traction substation where it is located; when the power of a traction substation is greater than zero, read the SOC capacity of the supercapacitor in the corresponding energy storage system information; if the SOC capacity of the energy storage system of the traction substation is greater than the lower capacity limit, the energy storage system of the traction substation is discharged; judge whether the instantaneous active power of the left power supply arm of the traction substation is greater than zero; if yes, the energy storage system of the traction substation enters the left power supply arm discharging mode of the traction substation; otherwise, the energy storage system of the traction substation enters the right power supply arm discharging mode of the traction substation.

9. The method for controlling and distributing brake energy recovery in electrified railways according to claim 7 or 8, characterized in that, Step S22 includes: Power conditioner regulation mode: when the power of the first traction substation is less than zero and the power of the second traction substation is greater than zero: if |P1|<P2, the central processing host controls active power |P1| to be transferred from the first traction substation to the second traction substation; if |P1|>P2, the central processing host controls active power P2 to be transferred from the first traction substation to the second traction substation; when the power of the first traction substation is greater than zero and the power of the second traction substation is less than zero: if |P2|<P1, the central processing host controls active power of -|P2| to be transferred from the second traction substation to the first traction substation; if |P2|<P1, the central processing host controls active power of -P1 to be transferred from the second traction substation to the first traction substation; Charging and discharging modes of the energy storage system: when the power of the traction substation is less than zero and the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system of the traction substation to enter the left power supply arm charging mode of the traction substation where it is located; when the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system to enter the right power supply arm charging mode of the traction substation where it is located, and after being fully charged, the energy storage system enters a standby state to wait for a control instruction; when the power of the traction substation is greater than zero and the instantaneous active power of the left arm is greater than zero, the central processing host controls the energy storage system of the traction substation to enter the left power supply arm discharging mode of the traction substation where it is located; when the instantaneous active power of the left arm is less than zero, the central processing host controls the energy storage system to enter the right power supply arm discharging mode of the traction substation where it is located, and after being fully discharged, the energy storage system enters a standby state to wait for a control instruction.

10. The method for controlling and distributing brake energy recovery in electrified railways according to claim 5, characterized in that, The braking energy recovery control and distribution method further comprises: predicting the operating time of the braking energy recovery control and distribution system in the first and second energy storage system charging and discharging modes and the power conditioner mode, and setting a system start-up time threshold and a start-up threshold for regenerative braking energy recovery according to the predicted operating time.

Images