Control method, system and electronic device for traction power supply of a train

Abstract

The application discloses a control method, system and electronic equipment for traction power supply of a train. The control method comprises the following steps: obtaining the running power of the train, first circuit parameters, second circuit parameters and third circuit parameters; determining the state of charge of the on-board battery based on the second circuit parameters, and obtaining first output power and second output power through a preset fuzzy logic model; determining negative sequence current according to the second circuit parameters and the third circuit parameters; determining the respective compensation currents of the ground energy storage system and the on-board battery in any working state based on the negative sequence current and a preset standard negative sequence current, so as to offset the negative sequence current generated by the traction catenary; and the traction catenary supplies power to the train at the first output power, and the on-board battery supplies power to the train at the second output power. The system and the electronic equipment are used for executing the control method for the traction power supply of the train. Through the above arrangement, the stability of the power supply to the train and the energy efficiency during the running of the train can be improved.

Description

Technical Field

[0001] This application relates to the field of railway power supply management technology, and in particular to a control method and system for train traction power supply. Background Technology

[0002] In current railway operations, most trains rely on high-voltage power grids to establish an electrified railway traction power supply control system, making train operation highly dependent on the traction overhead contact line. However, electrically driven trains can be considered a high-power, asymmetrical, and pulse-characteristic single-phase load for the traction overhead contact line. When the traction overhead contact line supplies power to the train, fluctuations in the traction load caused by the train can lead to three-phase imbalance in the traction overhead contact line, resulting in negative-sequence current. This negative-sequence current affects the stability of the traction overhead contact line power supply.

[0003] Meanwhile, most existing trains rely solely on the traction contact network for power supply. In order to ensure that the traction contact network can stably support the operation of the train, a large-volume traction transformer is usually installed so that the traction contact network can adapt to the power supply requirements of the train operation. However, an excessively large traction transformer will increase the energy consumption of the train, thereby affecting the train's operating energy efficiency. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the purpose of this application is to provide a control method, system and electronic equipment for traction power supply of a train, which can improve the stability of power supply to the train and the energy efficiency during train operation.

[0005] To achieve the above objectives, this application adopts the following technical solution:

[0006] In a first aspect, embodiments of this application provide a control method for traction power supply of a train, including:

[0007] The system acquires the train's operating power, first circuit parameters of the traction contact network, second circuit parameters of the onboard battery, and third circuit parameters of the ground energy storage system, where each circuit parameter includes resistance, voltage, and current. Based on the second circuit parameters, the system determines the state of charge (SOC) of the onboard battery. The SOC, first circuit parameters, and train operating power are then input into a preset fuzzy logic model to obtain the first output power of the traction contact network and the second output power of the onboard battery. The system determines the negative sequence current generated by the traction contact network according to the second circuit parameters of the onboard battery and the third circuit parameters of the ground energy storage system under different operating states, where operating states include standby, discharging, and charging. Based on the negative sequence current and a preset standard negative sequence current, the system determines the compensation current for each of the ground energy storage system and the onboard battery under any operating state. The traction contact network provides traction power to the train with the first output power, and the onboard battery provides the second output power. The onboard battery and the ground energy storage system use their respective compensation currents to offset the negative sequence current generated by the traction contact network.

[0008] Furthermore, determining the state of charge (SOC) of the vehicle battery based on the second circuit parameters includes: acquiring the open-circuit voltage, output voltage, and internal resistance of the vehicle battery to determine the internal current of the vehicle battery; acquiring the discharge time of the vehicle battery and determining the maximum value of the battery capacity of the vehicle battery based on the product of the internal current of the vehicle battery and the discharge time; and obtaining the SOC of the vehicle battery based on the maximum value of the battery capacity and the discharge time of the vehicle battery.

[0009] Further, obtaining the first output power of the traction contact network includes: determining the first membership function corresponding to the train's operating power and the second membership function corresponding to the state of charge of the on-board battery; obtaining the first fuzzy subset of the first membership function and the second fuzzy subset of the second membership function, and obtaining the third membership function based on the correspondence between the first fuzzy subset and the second fuzzy subset; defuzzifying the third membership function based on the weighted average method to obtain the first scaling factor and the first centroid value, and obtaining the product of the first centroid value and the first scaling factor to obtain the first output power.

[0010] Further, obtaining the second output power of the traction contact network includes: obtaining the difference between the train's operating power and the first output power to obtain the train's remaining operating power; substituting the train's remaining operating power and the state of charge of the on-board battery into the membership function to obtain the fourth membership function corresponding to the train's remaining operating power; obtaining the third fuzzy subset of the fourth membership function, and obtaining the fifth membership function based on the correspondence between the second and third fuzzy subsets; defuzzifying the fifth membership function based on the weighted average method to obtain the second scaling factor and the second centroid value, and obtaining the product of the second centroid value and the second scaling factor to obtain the second output power.

[0011] Furthermore, the standard negative sequence current includes a preset probability negative sequence current and a maximum probability negative sequence current. Determining the compensation current for the ground energy storage system and the vehicle battery under any operating state includes: obtaining a first probability and a second probability corresponding to the preset probability negative sequence current, where the second probability is the standard probability of the preset probability negative sequence current; obtaining a first maximum probability and a second maximum probability corresponding to the maximum probability negative sequence current, where the second maximum probability is the standard probability of the maximum probability negative sequence current; obtaining the preset probability current, the maximum probability current, and the active and reactive components of the operating power; comparing the first probability and the second probability, and comparing the first maximum probability and the second maximum probability, and determining the compensation current based on the negative sequence current, the preset probability negative sequence current, the maximum probability negative sequence current, the preset probability current, the maximum probability current, the active and reactive components of the operating power.

[0012] Furthermore, based on the negative sequence current and a preset standard negative sequence current, the compensation current of the ground energy storage system and the vehicle battery under any operating state is determined, including: obtaining the ratio of the input voltage of the traction substation to the voltage of the traction contact network for the vehicle battery and the ground energy storage system under different operating states; obtaining the product of the train's operating power, the first circuit parameters of the traction contact network, the ratio of the input voltage of the traction substation to the voltage of the traction contact network, and a constant to determine the negative sequence current; comparing the first probability and the second probability, and comparing the first maximum probability and the second maximum probability, and based on the negative sequence current, preset probability negative sequence current, maximum probability negative sequence current, preset probability current, maximum probability current, active component and reactive component of the operating power corresponding to the vehicle battery and the ground energy storage system under different operating states, to determine the compensation current of the vehicle battery and the ground energy storage system under different operating states.

[0013] Furthermore, the compensation currents for the ground-based energy storage system and the vehicle-mounted battery are determined under any operating state. When the first probability is greater than the second probability, and the first maximum probability is greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is greater than the maximum probability current, the calculation formula for the compensation current is as follows:

[0014] ;

[0015] When the first probability is greater than the second probability, and the first maximum probability is not greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is less than the maximum probability current, the calculation formula for the compensation current is as follows:

[0016] ;

[0017] When the first probability is not greater than the second probability, and the first maximum probability is greater than the second maximum probability, and the preset probability negative sequence current is less than the preset probability current, and the maximum probability negative sequence current is greater than the maximum probability current, the calculation formula for the compensation current is as follows:

[0018] ;

[0019] in, This is the ratio of the input voltage of the traction substation to the voltage of the traction contact network. The active component of the operating power. To compensate for the current, The reactive component of the operating power. For the preset probability current, It is a negative sequence current. The preset probability negative sequence current. This represents the maximum probability current.

[0020] Secondly, embodiments of this application provide a traction power supply control system for driving train operation, including a power supply device and a central control device. The power supply device is used to provide electrical energy and includes a traction contact network, an on-board battery, and a ground energy storage system. The central control device is electrically connected to the power supply device, and the central control device executes the above-mentioned traction power supply control method when receiving electrical energy output from the power supply device.

[0021] Furthermore, the on-board battery includes a serial battery link, a battery fuse contactor, and a fuse switch. The serial battery link includes multiple battery modules connected in series, with adjacent serial battery links connected in parallel. The battery circuit fuse is used to disconnect the circuit connection between the on-board battery and the train, and the battery circuit fuse is electrically connected to one end of the train and the serial battery link. The battery fuse contactor is used to disconnect the internal circuit connection of the on-board battery, and the battery fuse contactor is electrically connected to both ends of the serial battery link. The fuse switch is used to electrically isolate adjacent batteries in the serial battery link, and the fuse switch is installed between two adjacent battery modules.

[0022] Thirdly, embodiments of this application provide an electronic device, including a memory and a processor. The memory stores a computer program, and the processor runs the computer program to perform the aforementioned traction power supply control method.

[0023] The aforementioned traction power supply control method allocates the output power of the onboard battery and traction contact network to the train through a fuzzy logic model. This reduces the train's dependence on the traction contact network power supply, allowing the output power of the traction contact network to not need to meet the peak power requirements of the train operation. This reduces the size of the traction transformer, thus avoiding the energy consumption caused by an excessively large traction transformer and improving the train's operational energy efficiency. Simultaneously, the ground energy storage system and onboard battery can provide compensation current to counteract the negative sequence current in the traction contact network, thereby improving the stability of the traction contact network power supply. Attached Figure Description

[0024] Figure 1 This is a hardware structure block diagram of an electronic device according to an embodiment of this application.

[0025] Figure 2 This is a flowchart of a traction power supply control method according to an embodiment of this application.

[0026] Figure 3 This is a flowchart illustrating step S2 in an embodiment of this application.

[0027] Figure 4 This is a function graph of the first membership function in an embodiment of this application.

[0028] Figure 5 This is a function graph of the second membership function in an embodiment of this application.

[0029] Figure 6 This is a function graph of the third membership function in an embodiment of this application.

[0030] Figure 7 This is a function graph of the fourth membership function in an embodiment of this application.

[0031] Figure 8 This is a function graph of the fifth membership function in an embodiment of this application.

[0032] Figure 9 This is a flowchart illustrating step S4 in an embodiment of this application.

[0033] Figure 10 This is a flowchart illustrating the determination of the compensation current in an embodiment of this application.

[0034] Figure 11 This is a structural block diagram of a train traction power supply control system according to an embodiment of this application.

[0035] Figure 12 This is a circuit diagram of a vehicle battery according to an embodiment of this application. Detailed Implementation

[0036] The present application will be described in detail below with reference to the specific embodiments shown in the accompanying drawings. However, these embodiments do not limit the present application. Any structural, methodological, or functional modifications made by those skilled in the art based on these embodiments are included within the protection scope of the present application.

[0037] The train traction power supply control method provided in this embodiment can be executed in electronic device 100 or similar device. Figure 1 This is a hardware structure block diagram of an electronic device 100 that implements an embodiment of this application. For example... Figure 1 As shown, the electronic device 100 may include one or more ( Figure 1 (Only one is shown in the image) Memory 12 and processor 11. This electronic device 100 is the control terminal of the train system. It is used to control the operation of each train in the train system and to allocate the output power of the traction contact network and on-board battery as described below according to the train's operating requirements, so that the train can run and reduce the energy consumption during train operation.

[0038] The memory 12 stores program instructions, such as application software programs and modules, like the computer program for a train traction power supply control method in this embodiment. The processor 11 executes the program instructions stored in the memory 12. By running the computer program stored in the memory 12, it can perform various functional applications and data processing, that is, control the traction contact network and the on-board battery to supply traction power to the train.

[0039] The processor 11 may include, but is not limited to, a microprocessor 11 (Microcontroller Unit, abbreviated as MCU) or a programmable gate array (FPGA).

[0040] Those skilled in the art will understand that Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the electronic device 100 described above. For example, the electronic device 100 may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown are illustrated.

[0041] In some embodiments, a portion of the control method for traction power supply of the train described below is executed in electronic device 100, while the remainder of the control method for traction power supply of the train is executed on the train to distribute the output power of the traction contact network and the on-board battery and to counteract the negative sequence current in the traction contact network.

[0042] This embodiment also provides a control method for train traction power supply. Figure 2This is a flowchart of a train traction power supply control method according to an embodiment of this application. The train traction power supply control method is used to improve the stability of power supply to the train and the energy efficiency during train operation.

[0043] like Figure 2 As shown in the embodiments provided in this application, the control method for train traction power supply includes the following steps:

[0044] Step S1: Obtain the train's operating power, the first circuit parameters of the traction contact network, the second circuit parameters of the onboard battery, and the third circuit parameters of the ground energy storage system. Each circuit parameter includes the circuit's resistance, the voltage applied to the circuit, and the current flowing through the circuit. This setup, by obtaining the train's operating power and circuit parameters, facilitates the subsequent acquisition of compensation current and the subsequent allocation of power between the onboard battery and the traction contact network.

[0045] Step S2: Determine the state of charge of the on-board battery based on the second circuit parameters, and input the state of charge, the first circuit parameters and the train's operating power into a preset fuzzy logic model to obtain the first output power of the traction contact network and the second output power of the on-board battery.

[0046] A fuzzy logic model is a mathematical framework that mimics human thinking and decision-making. It is used to process precise input data into outputs that conform to human intuition through experience-based fuzzy rules. In this application, fuzzy rules are used to process the state of charge of the onboard battery, the first circuit parameters, and the train's operating power to allocate the output power of the onboard battery and the traction contact network. This can reduce the train's dependence on the traction contact network for power supply, so that the traction contact network does not need to meet the peak power requirements of the train's operation. This can reduce the size of the traction transformer, thereby reducing the energy consumption of the train carrying the traction transformer during operation and improving the energy efficiency of the train.

[0047] like Figure 3 As shown, in some embodiments, the step S2 of determining the state of charge of the vehicle battery based on the second circuit parameters includes:

[0048] Step S21: Obtain the open-circuit voltage, output voltage, and internal resistance of the vehicle battery to determine the internal current of the vehicle battery. The formula for determining the internal current is as follows:

[0049] ;

[0050] in, This refers to the internal current of the vehicle battery. This refers to the open-circuit voltage of the vehicle battery. This refers to the output voltage of the vehicle battery. The internal resistance of the vehicle battery is given. The internal current of the vehicle battery can be calculated using the formula for internal current described above. In some embodiments, the open-circuit voltage, output voltage, and internal resistance of the vehicle battery can be obtained through the RINT equivalent circuit model to determine the internal current of the vehicle battery; this application does not impose any limitations on this.

[0051] In this embodiment, by determining the internal current This will facilitate the subsequent determination of the vehicle's battery capacity.

[0052] Step S22: Obtain the discharge time of the vehicle battery, and determine the maximum battery capacity of the vehicle battery based on the product of the internal current of the vehicle battery and the discharge time.

[0053] The formula for determining the battery capacity of the aforementioned vehicle battery is as follows:

[0054] ;

[0055] in, This refers to the battery capacity of the vehicle's onboard battery. It is a constant. The discharge time of the vehicle battery is used as the starting point. The battery capacity can be calculated under different time conditions using the formula described above. Then, the battery capacity with the largest value among the calculation results is obtained, thus determining the maximum battery capacity of the vehicle battery.

[0056] In this embodiment, the state of charge is the ratio between the remaining charge in the vehicle battery and its rated capacity. Determining the state of charge of the vehicle battery is beneficial for the real-time battery capacity.

[0057] Step S23: Obtain the state of charge of the vehicle battery based on the maximum battery capacity and the discharge time of the vehicle battery.

[0058] The formula for determining the state of charge (SOC) of a vehicle battery is as follows:

[0059] ;

[0060] in, This refers to the state of charge of the vehicle battery at the next moment. This represents the current state of charge of the vehicle's battery. This represents the maximum capacity of the vehicle battery. In other words, the formula for determining the state of charge (SOC) of the vehicle battery described above can be used to calculate the SOC of the vehicle battery at different times.

[0061] In this embodiment, by obtaining the state of charge of the vehicle battery, it is beneficial to control the output power of the vehicle battery to provide power according to the state of charge of the vehicle battery and the power demand during train operation.

[0062] like Figure 3 As shown, the step of obtaining the first output power of the traction contact network in step S2 includes:

[0063] Step S24: Determine the first membership function corresponding to the train's operating power and the second membership function corresponding to the state of charge of the onboard battery. A membership function is a function used to describe the degree of membership of an element to a certain fuzzy set. The membership function can map the input element to a value in the range [0,1], which helps to represent the degree to which the input element belongs to the fuzzy set.

[0064] The above settings utilize a first membership function to fuzzify the train's operating power according to fuzzy rules, and a second membership function to fuzzify the state of charge (SBC) of the onboard battery according to fuzzy rules. This reduces the impact of changes in the train's operating power and the SBC of the onboard battery on the accuracy of determining the first output power, thereby reducing the dependence on the accuracy of the train's operating power and the SBC of the onboard battery and improving the robustness of subsequently obtaining the first output power. In this application, the first and second membership functions use Gaussian membership functions and generalized bell-shaped membership functions as input membership functions. The Gaussian membership function is as follows:

[0065] ;

[0066] The generalized bell-shaped membership function is:

[0067] ;

[0068] in, , , , All are constants. As the input quantity, the train's operating power is input in the first membership function to obtain, for example... Figure 4 The diagram shows the fuzzy subset graph of the first membership function, which is the membership function of the train's operating power. Figure 4 The horizontal and vertical axes represent the membership degree of different train operating power, ranging from -1.0 to 1.0. The input in the second membership function is the state of charge of the onboard battery. This is used to obtain... Figure 5 The second membership function, shown in the fuzzy subset graph, represents the membership function of the vehicle battery's state of charge. Figure 5 The horizontal and vertical axes represent the degree of membership of different states of charge of the vehicle battery, with the membership range including [-1.0, 1.0].

[0069] Step S25: Obtain the first fuzzy subset of the first membership function and the second fuzzy subset of the second membership function, and obtain the third membership function according to the correspondence between the first fuzzy subset and the second fuzzy subset. In the above settings, the third membership function is the result function after the fuzzy rule processing of the first output power, which is beneficial for obtaining the first output power in the future, thereby facilitating the subsequent allocation of the output power of the on-board battery and traction contact network to power the train. In this application, the first fuzzy subset is {NH, NM, NL, PL, PM, PH}, the second fuzzy subset is {VL, L, M, H, VH}, and the third membership function is obtained using triangular membership function and trapezoidal membership function, wherein the triangular membership function is:

[0070] ;

[0071] The trapezoidal membership function is:

[0072] ;

[0073] The third membership function, obtained through the triangular and trapezoidal membership functions, is used to obtain, for example... Figure 6 The fuzzy subset graph of the third membership function is shown, which is the membership function of the first output power. Figure 5 The horizontal and vertical axes represent the membership degrees of different first output powers, ranging from -1.0 to 1.0. The fuzzy subset of the third membership function is {P0, P1, P2, P3, P4, P5}. The correspondence (i.e., fuzzy rules) between the first, second, and third fuzzy subsets is shown in the table below:

[0074]

[0075] in, The power of the traction overhead contact line is [value], and the train's operating power is [value]. That is, the fuzzy subset of the third membership function can be determined by the first fuzzy subset, the second fuzzy subset, and the fuzzy rules in the table above. Thus, the third membership function can be determined by defuzzification in the future, which is beneficial for obtaining the first output power.

[0076] Step S26: Defuzzify the third membership function based on the weighted average method to obtain the first scaling factor and the first centroid value, and obtain the product of the first centroid value and the first scaling factor to obtain the first output power.

[0077] In this application, the preset operating power threshold range of the train is [0, ], This represents the maximum operating power of the train. In the above settings, the preset... For any point within the output range where the first output power is, then that point has a corresponding membership value in the third membership function. The expression for calculating the value of the first centroid is:

[0078] ;

[0079] in, The first centroid value is determined by calculating its expression. The expression for calculating the first scale factor is as follows:

[0080] ;

[0081] in, The first scaling factor is defined by its expression. The first scaling factor is then determined by multiplying the first centroid value and the first scaling factor. The expression for calculating the first output power is as follows:

[0082] ;

[0083] in The first output power is determined by calculating its expression. As one implementation, step S2, obtaining the second output power of the vehicle battery, includes:

[0084] Step S27: Obtain the difference between the train's operating power and the first output power to get the train's remaining operating power. The formula for calculating the train's remaining operating power is as follows:

[0085] ;

[0086] in, The remaining operating power of the train can be calculated using the formula described above.

[0087] Step S28: Substitute the train's remaining operating power and the state of charge of the on-board battery into the membership function to obtain the fourth membership function corresponding to the train's remaining operating power; obtain the third fuzzy subset of the fourth membership function, and obtain the fifth membership function based on the correspondence between the second and third fuzzy subsets.

[0088] As described above, the remaining operating power of the train can be fuzzified according to fuzzy rules through the fourth membership function, so as to reduce the impact of changes in the remaining operating power of the train on the accuracy of determining the second output power, thereby reducing the dependence on the accuracy of the remaining operating power of the train and improving the robustness of obtaining the second output power in the future.

[0089] In this application, the fourth membership function can be obtained by processing the Gaussian membership function and the generalized bell-shaped membership function, and used as the input membership function to obtain, as shown in the following example. Figure 7 The fuzzy subset graph of the fourth membership function shown represents the membership function of the train's remaining operating power. Figure 7 The horizontal and vertical axes represent the membership degree of different trains' remaining operating power, ranging from -1.0 to 1.0. The fifth membership function can be obtained through triangular and trapezoidal membership functions and used as the output membership function to achieve the following: Figure 8 The fuzzy subset graph of the fifth membership function is shown, which is the membership function of the second output power. Figure 8 The horizontal and vertical axes represent the membership degrees of different second output powers, ranging from [-1.0, 1.0]. Furthermore, the third fuzzy subset is {NH, NM, NL, PL, PM, PH}, and the fuzzy subset of the fifth membership function is {NH, NM, NL, Z, PL, PM, PH}. The correspondence (i.e., fuzzy rules) between the second, third, and fifth fuzzy subsets is shown in the table below:

[0090]

[0091] That is, the fuzzy subset of the fifth membership function can be determined by the second fuzzy subset, the third fuzzy subset, and the fuzzy rules in the table above, so as to determine the required fifth membership function, which is beneficial for obtaining the second output power in the future.

[0092] Step S29: Defuzzify the fifth membership function based on the weighted average method to obtain the second scaling factor and the second centroid value, and obtain the product of the second centroid value and the second scaling factor to obtain the second output power.

[0093] In this application, the threshold range of the second output power of the preset vehicle battery is [0, ], This is the maximum value of the second output power of the vehicle battery. In the above settings, the preset... For any point within the output range where the second output power is, then that point has a corresponding membership value in the fifth membership function. The expression for calculating the value of the second centroid is:

[0094] ;

[0095] in, The second centroid value can be determined by calculating its expression. The expression for calculating the second scale factor is as follows:

[0096] ;

[0097] in, The second scaling factor can be determined by calculating its expression. The second centroid value is then calculated as the product of the second scaling factor to determine the second output power. The expression for calculating the first output power is as follows:

[0098] ;

[0099] in The first output power is the first output power, and the second output power of the vehicle battery can be determined by calculating the expression for the second output power.

[0100] For example, a first output power and a second output power can be obtained through a fuzzy logic controller. The fuzzy logic controller that obtains the first output power is defined as the first fuzzy logic controller, and the fuzzy logic controller that obtains the second output power is defined as the second fuzzy logic controller. By inputting the state of charge of the on-board battery and the operating power of the train into the first fuzzy logic controller, the first output power of the traction overhead contact line can be obtained.

[0101] Because the negative sequence current needs to be offset by power supplied by the onboard battery during the process of traction power supply to the train, the state of charge (SBC) of the onboard battery (after offsetting the negative sequence current) and the remaining operating power of the train are input into the second fuzzy logic controller to obtain the second output power of the onboard battery. In the above setting, the train operating power required by the traction power supply to the traction power supply is determined by the first fuzzy logic controller, and the input of the second fuzzy logic controller is limited based on the output of the first fuzzy logic controller. This improves the accuracy of the input of the second fuzzy logic controller, thereby improving the accuracy of obtaining the second output power. Furthermore, it improves the accuracy of the control method for traction power supply, allocating the power supply ratio between the onboard battery and the traction power supply to the train, thus improving the energy efficiency of train operation.

[0102] Meanwhile, setting up two fuzzy logic controllers can simultaneously control the state of charge of the on-board battery and the output power of the traction contact network. This allows the train's traction power supply control method to accurately adjust and obtain the first and second output powers even when the state of charge of the on-board battery and the output power of the traction contact network fluctuate. This improves the robustness of the train's traction power supply control method in handling the power of the traction contact network and the state of charge of the on-board battery.

[0103] like Figure 2As shown, the operating states of the vehicle-mounted battery and the ground-based energy storage system include standby, discharging, and charging states. Step S3 determines the negative-sequence current generated by the traction contact network based on the second circuit parameters of the vehicle-mounted battery and the third circuit parameters of the ground-based energy storage system under different operating states. Negative-sequence current refers to the current generated in a three-phase power system due to unbalanced loads or faults. In this application, both the vehicle-mounted battery and the ground-based energy storage system are connected to the traction contact network. Therefore, during the power supply process of the traction contact network, the operating states of both the vehicle-mounted battery and the ground-based energy storage system will affect the negative-sequence current in the traction contact network. As described above, the accuracy of the determined negative-sequence current can be improved, thereby improving the accuracy of the subsequently determined compensation current. This facilitates the offsetting of the negative-sequence current through the compensation current, and further improves the stability of the traction contact network during power supply.

[0104] In some embodiments, when the on-board battery and ground energy storage system are in standby mode, they have no effect on the traction contact network; therefore, the traction contact network bears all traction negative charges. The negative sequence current of the traction contact network can be determined by obtaining and calculating the product of the ratio of the traction substation input voltage to the traction contact network voltage, the load current during train operation, and a constant. The formula for calculating the negative sequence current is as follows:

[0105] ;

[0106] in, It is a negative sequence current. This is the ratio of the input voltage of the traction substation to the voltage of the traction contact network. This refers to the load current during train operation. That is, the negative sequence current of the traction contact network when the onboard battery and ground energy storage system are in standby mode can be determined using the above calculation formula for negative sequence current.

[0107] In some embodiments, when the on-board battery and ground energy storage system are in a discharging state, the electrical energy obtained by the on-board battery and ground energy storage system from the traction contact network can be reduced, thereby reducing the peak value of the traction negative charge borne by the traction contact network, which helps to reduce the negative sequence current in the traction contact network. The negative sequence current of the traction contact network can be determined by obtaining the ratio of the input voltage of the traction substation to the voltage of the traction contact network, the active component of the train's operating power, the reactive component of the train's operating power, and the discharge current of the on-board battery and ground energy storage system. The formula for calculating the negative sequence current is as follows:

[0108] ;

[0109] in, This refers to the active component of the train's operating power. This refers to the discharge current of the vehicle-mounted battery and the ground-based energy storage system. This represents the reactive component of the train's operating power. That is, the negative sequence current of the traction contact network when the onboard battery and ground energy storage system are in a discharging state can be determined using the above calculation formula for negative sequence current.

[0110] In some embodiments, when the vehicle-mounted battery and ground-based energy storage system are charging, they need to draw power from the external power grid. In this case, if the vehicle-mounted battery and ground-based energy storage system are charged via the traction contact network, it will increase the peak value of the traction negative charge on the traction contact network, thereby increasing the negative sequence current within the traction contact network. The formula for calculating the negative sequence current is as follows:

[0111] ;

[0112] in, This refers to the charging current of the traction contact network. That is, the negative sequence current when the traction contact network charges the onboard battery and ground energy storage system can be calculated using the formula for negative sequence current described above.

[0113] If the onboard battery and ground energy storage system are charged using the electrical energy generated during train braking, they will not affect the traction contact network, thus ensuring that the negative sequence current within the traction contact network remains unaffected. The formula for calculating the negative sequence current of the traction contact network under these conditions is as follows:

[0114] ;

[0115] in, This refers to the current returning to the traction contact network when the train brakes. In other words, the negative sequence current in the traction contact network can be calculated using the formula described above for calculating the negative sequence current. This formula allows us to calculate the negative sequence current in the traction contact network when the electrical energy generated during train braking charges the onboard battery and ground energy storage system.

[0116] like Figure 2 As shown, step S4 determines the compensation current for the ground energy storage system and the vehicle battery under any operating state based on the negative sequence current and a preset standard negative sequence current. In this application, the preset standard negative sequence current is the 95% probability value of the negative sequence current allowed by national standards. The 95% probability value of the negative sequence current is the current value that is lower than or equal to the negative sequence current for 95% of the time within a statistical period (which can be one day, one week, or one month). In the above settings, calculating the corresponding compensation current based on the negative sequence current under different operating states of the ground energy storage system and the vehicle battery can improve the accuracy of the compensation current calculation, thereby helping the compensation current to offset the negative sequence current and improve the stability of the traction contact network power supply.

[0117] The standard negative sequence current includes the preset probability negative sequence current and the maximum probability negative sequence current. In this application, the calculation formulas for the preset probability negative sequence current and the maximum probability negative sequence current are as follows:

[0118] ;

[0119] in, This refers to the short-circuit capacity of the common connection point within the traction catenary, which is the electrical connection point between the traction catenary and the train. This refers to the voltage of the traction contact network. That is, the preset probability negative sequence current and the maximum probability negative sequence current can be calculated using the formulas mentioned above. For example... Figure 9 The steps in step S4 shown, which determine the compensation currents of the ground-based energy storage system and the vehicle-mounted battery under any operating condition, include:

[0120] Step S41: Obtain the first probability and the second probability corresponding to the preset probability negative sequence current. The second probability is the standard probability of the preset probability negative sequence current. In the above settings, the first probability is the probability corresponding to the 95% probability value of the negative sequence current. Obtaining the first probability and the second probability is helpful for subsequently determining the compensation current.

[0121] Step S42: Obtain the first maximum probability and the second maximum probability corresponding to the maximum probability negative sequence current. The second maximum probability is the standard probability of the maximum probability negative sequence current. In the above settings, the maximum probability negative sequence current is the maximum probability value of negative sequence current allowed by national standards, that is, the current value that is lower than or equal to the negative sequence current for all times within the statistical period (which can be one day, one week, or one month). The first maximum probability is the probability corresponding to the maximum probability value of the negative sequence current. Obtaining the above first maximum probability and second maximum probability is helpful for subsequently determining the compensation current.

[0122] Step S43: Obtain the preset probability current, the maximum probability current, and the active and reactive components of the operating power. These settings are helpful for subsequently determining the compensation current.

[0123] Step S44: Compare the first probability and the second probability, and compare the first maximum probability and the second maximum probability. Determine the compensation current based on the negative sequence current, the preset probability negative sequence current, the maximum probability negative sequence current, the preset probability current, the maximum probability current, and the active and reactive components of the operating power. Through the above settings, the compensation current required to be applied to the traction contact network under different probability conditions is distinguished and determined. This improves the accuracy of the determined compensation current, which helps to offset the negative sequence current, thereby improving the stability of the traction contact network power supply.

[0124] For example, the first probability is set to The first maximum probability is set to The preset probability negative sequence current is set to The preset probability current is set to The maximum probability negative sequence current is set as The maximum probability current is set to Taking a second probability of 1.3% and a second maximum probability of 2.6% as an example, the compensation current of the ground energy storage system and the vehicle battery under any operating state includes the following three cases. In some embodiments, when the first probability is greater than the second probability, and the first maximum probability is greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is greater than the maximum probability current, that is, the following conditions are met. The formula for calculating the compensation current at any given time is as follows:

[0125] ;

[0126] in, Let be the negative sequence current at any given time. Let be the compensation current at any given time. Let be the useful work component of the train's operating power at any given time. This represents the useless power component of the train's operating power at any given time. It is determined using the aforementioned relationship regarding the compensation current. , , , The compensation current at that time.

[0127] In some embodiments, when the first probability is greater than the second probability, and the first maximum probability is not greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is less than the maximum probability current, that is, when the first probability is greater than the second probability, and the first maximum probability is not greater than the second maximum probability, the following conditions are met: The formula for calculating the compensation current at any given time is as follows:

[0128] ;

[0129] That is, determined from the above relationship regarding the compensation current. , , , The compensation current at that time.

[0130] In some embodiments, when the first probability is not greater than the second probability, and the first maximum probability is greater than the second maximum probability, and the preset probability negative sequence current is less than the preset probability current, and the maximum probability negative sequence current is greater than the maximum probability current, that is, the following conditions are met: , , , The formula for calculating the compensation current at any given time is as follows:

[0131] ;

[0132] That is, determined from the above relationship regarding the compensation current. , , , The compensation current at that time.

[0133] It should be noted that, according to the national standard GB / T15543-2008 "Power Quality - Three-Phase Voltage Imbalance", the 95% probability value of negative sequence voltage imbalance caused by a single user at the point of common coupling (PPC) for each load connected to the PPC is no greater than 1.3%, and the maximum value is no greater than 2.6%. That is, in this application, the second probability is preset to 1.3%, and the second maximum probability is preset to 2.6%.

[0134] In this application, after determining the compensation current, the on-board battery and the ground energy storage system simultaneously output the required compensation current to the common coupling point to offset the negative sequence current generated when the train is electrically connected to the traction contact network, thereby improving the stability of the traction contact network supplying power to the train.

[0135] Specifically, such as Figure 10 As shown, the steps for determining the compensation current of the ground-based energy storage system and the vehicle-mounted battery under any operating state, based on the negative sequence current and a preset standard negative sequence current, include:

[0136] Step S1001: Obtain the ratio of the input voltage of the traction substation to the voltage of the traction contact network for the on-board battery and ground energy storage system under different operating conditions. This setting facilitates the subsequent determination of the negative sequence current.

[0137] Step S1002: Obtain the product of the train's operating power, the first circuit parameters of the traction contact network, the ratio of the input voltage of the traction substation to the voltage of the traction contact network, and a constant, to determine the negative sequence current. Since the on-board battery and ground energy storage system in different operating states will affect the negative sequence current of the traction contact network, determining the negative sequence current based on the operating states of the on-board battery and ground energy storage system can improve the accuracy of the negative sequence current. The specific steps for determining the negative sequence current have been described above and will not be repeated here.

[0138] Step S1003: Compare the first probability and the second probability, and compare the first maximum probability and the second maximum probability. Based on the currents corresponding to the vehicle battery and ground energy storage system under different operating states, the preset probability negative sequence current, the maximum probability negative sequence current, the preset probability current, the maximum probability current, and the active and reactive components of the operating power, determine the compensation current of the vehicle battery and ground energy storage system under different operating states. Since the vehicle battery and ground energy storage system under different operating states will affect the negative sequence current of the traction contact network, causing the compensation current to change synchronously to offset the negative sequence current, in the above setting, determining the negative sequence current of the traction contact network corresponding to the vehicle battery and ground energy storage system under different operating states helps to improve the accuracy of determining the compensation current. The specific steps for determining the compensation current have been described above and will not be repeated here.

[0139] Step S5: The traction contact network provides traction power to the train with the first output power and the on-board battery provides the second output power. The on-board battery and the ground energy storage system use their respective compensation currents to offset the negative sequence current generated by the traction contact network.

[0140] This embodiment also provides a control system for traction power supply of a train, used to drive the train. The system includes a power supply unit and a central control unit. The power supply unit provides electrical energy and includes a traction contact network, an onboard battery, and a ground energy storage system. The central control unit is electrically connected to the power supply unit, and executes a control method for traction power supply of the train when receiving electrical energy output from the power supply unit.

[0141] In the above configuration, the power supply device includes an onboard battery and a traction contact network. The central control unit controls the power supply device to supply power to the train according to the traction power supply control method. That is, the central control unit allocates the output power of the onboard battery and the traction contact network according to the traction power supply control method, so that the onboard battery and the traction contact network supply traction power to the train according to the output power. This can reduce the output power requirement of the traction contact network when supplying power to the train, thereby reducing the size of the traction transformer and reducing the energy consumption of the train carrying the traction transformer during operation, thus improving the energy efficiency of the train during operation.

[0142] For example, such as Figure 11As shown, the train is equipped with motors that drive its operation. The train's traction power supply control system also includes traction transformers, converters, transformers, PWM rectifiers, and inverters. A traction transformer is a voltage conversion device in the control system of electrified railways and rail transit traction power supply, used to convert current from the high-voltage grid into current suitable for the voltage level of the traction contact network. A converter is an AC / DC conversion device used to convert AC power in the traction contact network into DC power for storage in a ground energy storage system, or to convert DC power in the ground energy storage system into AC power for transmission to the traction contact network. A transformer is a device that converts AC power of one voltage and current level into current of another voltage and current level without changing the frequency, using the principle of electromagnetic induction; it is used to convert AC power in the traction contact network into current suitable for train operation. A PWM rectifier is a current conversion device that uses fully controlled power devices and pulse width modulation (PWM) technology to rectify the circuit. An inverter is a device that converts direct current (DC) to alternating current (AC). It is used to convert the DC power from the onboard battery into AC power capable of driving the motor. In this application, the traction contact network draws current from the traction transformer and supplies power to the train. The onboard battery is connected to the train's motor via the inverter and drives the motor to rotate, thus propelling the train. The onboard battery is connected to the traction contact network via a transformer and a PWM rectifier, allowing the traction contact network to charge the onboard battery and enabling the onboard battery to offset the negative sequence current in the traction contact network through compensation current. A ground-based energy storage system is connected to the train and the traction contact network via a converter, allowing the ground-based energy storage system to store excess electrical energy during train operation and also enabling the ground-based energy storage system to offset the negative sequence current in the traction contact network through compensation current.

[0143] Specifically, such as Figure 12 As shown, the on-board battery includes a series battery link, a battery fuse contactor, and a fuse switch. The series battery link comprises multiple battery modules connected in series, with adjacent series battery links connected in parallel. In this configuration, connecting multiple battery modules in series increases the output voltage of the series battery link, thereby improving the efficiency of the on-board battery-driven motor and thus enhancing the train's energy efficiency. Simultaneously, connecting multiple series battery links in parallel ensures that the on-board battery capacity equals the sum of the capacities of all series battery links, thereby increasing the on-board battery capacity and extending the time the on-board battery supplies power to the train.

[0144] It should be noted that in this application, six serial battery links are connected in parallel in the vehicle battery, and 180 battery modules are connected in series in a single serial battery link, in order to improve the capacity and voltage of the vehicle battery.

[0145] Additionally, a battery fuse (BFL) is a safety protection device in a battery system. It disconnects the electrical connection between the vehicle battery and the train. The battery fuse electrically connects one end of the train to the series battery link. Installing a battery fuse disconnects the electrical connection between the vehicle battery and the train when a circuit fault occurs on the train side, thus preventing damage to the internal circuitry of the vehicle battery and extending its lifespan. A battery fuse contactor (BFC) is a safety device integrating the functions of a fuse and a contactor. It disconnects the internal circuitry of the vehicle battery. The battery fuse contactor electrically connects to both ends of the series battery link. Installing a battery fuse contactor disconnects the electrical connection between the faulty series battery link and other series battery links when a circuit fault occurs in any series battery link, preventing damage to the circuitry of other series battery links and improving the safety of the vehicle battery during operation. A fuse switch (FS) is a safety device that integrates the functions of a fuse and an isolating switch. It is installed between two adjacent battery modules to electrically isolate adjacent batteries in a series battery link. By installing a fuse switch, the circuit connection between the faulty battery and other batteries is severed when a circuit fault occurs in any battery, thus preventing damage to the circuits of other batteries and improving the safety of the vehicle's battery operation.

[0146] In the above embodiments, implementation can be achieved entirely or partially through software, hardware, firmware, or any combination thereof. When implemented using software, it can be implemented entirely or partially in the form of a computer program product. The computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the processes or functions described in the embodiments of this application are generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in a computer-readable storage medium or transmitted from one computer-readable storage medium to another. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired (e.g., coaxial cable, fiber optic, digital subscriber line (DSL)) or wireless (e.g., infrared, wireless, microwave, etc.) means. The computer-readable storage medium can be any available medium that a computer can access or a data storage device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium (e.g., floppy disk, hard disk, magnetic tape), an optical medium (e.g., DVD), or a solid-state drive (SSD), etc.

[0147] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0148] The various embodiments in this specification are described in a related manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on its differences from other embodiments. In particular, the system embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments. The above descriptions are merely preferred embodiments of this application and are not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A control method for traction power supply of a train, characterized in that, include: The train's operating power, the first circuit parameters of the traction contact network, the second circuit parameters of the on-board battery, and the third circuit parameters of the ground energy storage system are obtained, where any circuit parameter includes resistance, voltage, and current. The state of charge of the vehicle battery is determined based on the second circuit parameters, and the state of charge, the first circuit parameters, and the operating power of the train are input into a preset fuzzy logic model to obtain the first output power of the traction contact network and the second output power of the vehicle battery. The negative sequence current generated by the traction contact network is determined based on the second circuit parameters of the vehicle battery and the third circuit parameters of the ground energy storage system under different working states, wherein the working states include standby state, discharge state and charging state; Based on the negative sequence current and the preset standard negative sequence current, the compensation current of the ground energy storage system and the vehicle battery is determined in any of the above working states. The traction contact network provides traction power to the train with a first output power and the on-board battery provides a second output power. The on-board battery and the ground energy storage system use their respective compensation currents to offset the negative sequence current generated by the traction contact network.

2. The control method for train traction power supply according to claim 1, characterized in that, Determining the state of charge of the vehicle battery based on the second circuit parameters includes: The open-circuit voltage, output voltage, and internal resistance of the vehicle battery are obtained to determine the internal current of the vehicle battery. The discharge time of the vehicle battery is obtained, and the maximum battery capacity of the vehicle battery is determined based on the product of the internal current of the vehicle battery and the discharge time. The state of charge of the vehicle battery is obtained based on the maximum value of the battery capacity and the discharge time of the vehicle battery.

3. The control method for train traction power supply according to claim 1, characterized in that, Obtaining the first output power of the traction contact network includes: Determine the first membership function corresponding to the train's operating power and the second membership function corresponding to the state of charge of the on-board battery; Obtain the first fuzzy subset of the first membership function and the second fuzzy subset of the second membership function, and obtain the third membership function based on the correspondence between the first fuzzy subset and the second fuzzy subset; The third membership function is defuzzified using a weighted average method to obtain a first scaling factor and a first centroid value. The product of the first centroid value and the first scaling factor is then obtained to obtain the first output power.

4. The control method for train traction power supply according to claim 3, characterized in that, Obtaining the second output power of the traction contact network includes: The difference between the train's operating power and the first output power is obtained to determine the train's remaining operating power. Substitute the remaining operating power of the train and the state of charge of the on-board battery into the membership function to obtain the fourth membership function corresponding to the remaining operating power of the train; Obtain the third fuzzy subset of the fourth membership function, and obtain the fifth membership function based on the correspondence between the second fuzzy subset and the third fuzzy subset; The fifth membership function is defuzzified using a weighted average method to obtain the second scaling factor and the second centroid value. The product of the second centroid value and the second scaling factor is then obtained to obtain the second output power.

5. The control method for traction power supply of a train according to claim 3, characterized in that, The standard negative sequence current includes a preset probability negative sequence current and a maximum probability negative sequence current. Determining the compensation current for the ground-based energy storage system and the vehicle-mounted battery under any of the aforementioned operating states includes: Obtain the first probability and the second probability corresponding to the preset probability negative sequence current, wherein the second probability is the standard probability of the preset probability negative sequence current; Obtain the first maximum probability and the second maximum probability corresponding to the maximum probability negative sequence current, wherein the second maximum probability is the standard probability of the maximum probability negative sequence current; Obtain the active and reactive components of the preset probability current, the maximum probability current, and the operating power; The first probability and the second probability are compared, as are the first maximum probability and the second maximum probability, and the compensation current is determined based on the negative sequence current, the preset probability negative sequence current, the maximum probability negative sequence current, the preset probability current, the maximum probability current, the active component and the reactive component of the operating power.

6. The control method for train traction power supply according to claim 5, characterized in that, The determination of the compensation current for the ground-based energy storage system and the vehicle-mounted battery under any of the aforementioned operating states, based on the negative sequence current and a preset standard negative sequence current, includes: Obtain the ratio of the input voltage of the traction substation to the voltage of the traction contact network for the on-board battery and the ground energy storage system under different operating conditions; The negative sequence current is determined by multiplying the train's operating power, the first circuit parameters of the traction contact network, the ratio of the input voltage of the traction substation to the voltage of the traction contact network, and a constant. The first probability and the second probability are compared, as are the first maximum probability and the second maximum probability. Based on the negative sequence current of the vehicle battery and the ground energy storage system under different operating conditions, the preset probability negative sequence current, the maximum probability negative sequence current, the preset probability current, the maximum probability current, the active component and the reactive component of the operating power, the compensation current of the vehicle battery and the ground energy storage system under different operating conditions is determined.

7. The control method for train traction power supply according to claim 5, characterized in that, The compensation current for the ground energy storage system and the vehicle battery under any of the aforementioned operating states is determined as follows: when the first probability is greater than the second probability, and the first maximum probability is greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is greater than the maximum probability current, the calculation formula for the compensation current is as follows: ； When the first probability is greater than the second probability, and the first maximum probability is not greater than the second maximum probability, and the preset probability negative sequence current is greater than the preset probability current, and the maximum probability negative sequence current is less than the maximum probability current, the calculation formula for the compensation current is as follows: ； in, This is the ratio of the input voltage of the traction substation to the voltage of the traction contact network. The active component of the operating power. To compensate for the current, The reactive component of the operating power. For the preset probability current, It is a negative sequence current. The preset probability negative sequence current. This represents the maximum probability current.

8. A traction power supply control system for a train, used to drive the train, characterized in that, include: A power supply device and a central control device, wherein the power supply device is used to provide electrical energy and includes a traction contact network, an on-board battery and a ground energy storage system, and the central control device is electrically connected to the power supply device, and the central control device executes the traction power supply control method according to any one of claims 1 to 7 when receiving electrical energy output by the power supply device.

9. The traction power supply control system according to claim 8, characterized in that, The vehicle battery includes: a serial battery link comprising multiple battery modules connected in series, with adjacent serial battery links connected in parallel; a battery circuit fuse for disconnecting the circuit connection between the vehicle battery and the train, the battery circuit fuse being electrically connected to one end of the train and the serial battery link; a battery fuse contactor for disconnecting the internal circuit connection of the vehicle battery, the battery fuse contactor being electrically connected to both ends of the serial battery link; and a fuse switch for electrically isolating adjacent batteries in the serial battery link, the fuse switch being positioned between two adjacent battery modules.

10. An electronic device, characterized in that, include: A memory, a processor, and a computer program stored on the memory, wherein the processor is configured to run the computer program to perform the traction power supply control method according to any one of claims 1 to 7.

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