A traction power supply calculation method suitable for electrified highways

Abstract

The application provides a traction power supply calculation method suitable for electrified highways, and belongs to the field of electrified highway simulation.The method comprises a power supply model, a vehicle traction model and an energy storage device model.In vehicle operation, energy flows among the power supply system, the vehicle traction system and the energy storage device.The interface of the three systems is the DC bus of the vehicle, and the sum of the power of the three at the interface at any time is 0.In calculation, a transportation scheduling plan is established, driving parameters are configured, traction simulation is performed, the working condition of the energy storage device is judged, power supply simulation is performed, the traction network voltage is calculated, the rectifier unit is calculated, and finally the results are output.The judgment is made on whether the vehicle, the energy storage device and the power supply system meet the requirements.The method solves the double-source power supply calculation problem in the power supply system of the electrified highway, including: the power supply system simultaneously supplies power to the running vehicle and the parked charging vehicle;and the vehicle operation relies on the coordinated power supply of the power supply system and the energy storage device.

Description

Technical Field

[0001] This invention relates to the field of electrified highway simulation, and more specifically to a traction power supply calculation method applicable to electrified highways. Background Technology

[0002] An electrified highway is a road transportation system that provides electricity to vehicles by erecting a traction overhead contact line. Vehicles draw power from the power supply system via pantographs or similar devices and are equipped with onboard energy storage devices as a secondary energy source. When vehicles are running on electrified highways with overhead contact lines, they are powered by the power supply system and / or energy storage devices. When there is no overhead contact line, power is switched to the energy storage devices, ensuring a continuous supply of electricity. Electrified highways are suitable for bulk cargo transportation (such as coal and minerals), intercity freight, and are particularly suitable for freight transportation needs with fixed routes and sufficient power supply.

[0003] Electrified highways adopt a dual-source power supply system: 1) Overhead contact network power supply: 1500V or 750V DC power is used to transmit power through the overhead contact network, and the pantograph of the vehicle automatically raises and lowers to contact the network to obtain power; 2) On-board energy storage: The vehicle is equipped with an energy storage device, which is used to drive the vehicle in sections with or without overhead contact network (such as crossings, tunnels, and bridges) or when overtaking.

[0004] The simulation time for electrified highways is consistent with the transportation scheduling plan, typically 12 hours, 24 hours, or other cycles. Vehicle routes are determined by the transportation plan, but vehicle movement exhibits a degree of randomness, with each vehicle's trajectory being unique. During vehicle operation, energy flows between the power supply system, the vehicle traction system, and energy storage devices, making control and calculation methods complex. The power supply system must not only meet the vehicle's operational needs but also its charging needs during parking—necessaries that existing traction power supply calculation methods cannot address. Summary of the Invention

[0005] To address the dual-source power supply calculation problem in electrified highway power supply systems, this invention proposes a traction power supply calculation method applicable to electrified highways, which includes a power supply system simultaneously supplying power to both operating vehicles and parked charging vehicles; vehicle operation relies on the coordinated power supply from the power supply system and energy storage devices.

[0006] To solve the above problems, the present invention adopts the following technical solution:

[0007] A method for calculating traction power supply applicable to electrified highways, the method comprising the following steps:

[0008] The method includes a power supply model, a vehicle traction model, and an energy storage device model, and specifically includes the following steps:

[0009] Step 1: Based on the transportation task, establish a transportation scheduling plan and configure the driving parameters of all vehicles;

[0010] Step 2: Initialize the time, initialize the input of the power supply model, vehicle traction model and energy storage device model, set the cumulative calculation count to 1, and start the simulation;

[0011] Step 3: If it is the initial moment, set the entire network voltage to the rated voltage; otherwise, if the cumulative calculation count is 1, the network voltage setting is assigned according to the calculation result of the previous moment, otherwise it is assigned according to the calculation result of the previous moment.

[0012] Step 4: Traverse all vehicles, perform traction simulation, and calculate the power requirements of each vehicle;

[0013] Step 5: Iterate through all vehicle energy storage devices, determine operating conditions, and calculate power; if the remaining energy of the energy storage device is less than the lower limit of the remaining energy ratio, output "abnormal" and jump to step 9;

[0014] Step 6: Traverse all power supply systems, perform power supply simulation, and calculate the power of each rectifier unit, the current in the conductor, and the grid voltage at each node;

[0015] Step 7: Compare the relative values ​​of the calculated traction network voltage and the input network voltage. If the relative values ​​of all node network voltages are less than 1% or other preset values, proceed to step 9; otherwise, proceed to step 8.

[0016] Step 8: Determine the cumulative number of calculations at this moment. If it is less than 100 or other preset values, jump to step 3 and increment the cumulative number of calculations at this moment by 1. If the cumulative number of calculations is greater than 100 or other preset values, output "Abnormal" and jump to step 9.

[0017] Step 9: If there is no "abnormal" output at this moment, calculate the effective value of the rectifier power and the effective value of the conductor current within a certain period of time, and jump to step 10; otherwise, jump directly to step 10.

[0018] Step 10: If the simulation time is reached, proceed to step 11; otherwise, proceed to the next time step, set the cumulative calculation count to 1, and return to step 3.

[0019] Step 11: Output all results and determine whether the vehicle, energy storage device, and power supply system meet the requirements.

[0020] Furthermore, in step 1, the route for the operation of electrified highway vehicles in the transportation scheduling plan is determined by transportation demand. When external transportation demand occurs, the transportation task is assigned to specific vehicles through bidding or assignment, thus forming a transportation scheduling plan.

[0021] Furthermore, the power supply model includes rectifier units, overhead contact lines, and return lines; the vehicle traction model includes vehicles, tracks, and traffic flow; and the energy storage device model includes the charging and discharging power, efficiency, and stored energy of the energy storage device. In the calculation of traction power supply for electrified highways, the interface between the power supply model, the vehicle traction model, and the energy storage device model is the DC bus of the vehicle, and the sum of the power of the three at any given time is 0.

[0022] Furthermore, the power supply system in which the power supply model is located simultaneously supplies power to both the operating vehicles and the parked charging vehicles. The operation of the vehicles relies on the power supply system and the energy storage device to work together to supply power. The time period for power supply calculation refers to the period of the transportation scheduling plan, which is 12 hours, 24 hours or other. The power supply calculation is based on a steady-state model, with a time interval of 1 second, 2 seconds or other.

[0023] Furthermore, when the vehicle traction model is calculated, the vehicle takes leaving the charging device as the starting point and the current position as the initial condition for traction calculation. The vehicle traction is calculated based on the vehicle's operating state, determining the mechanical and electrical power generated by the vehicle traction system. The mechanical power calculation method is as follows:

[0024] ;

[0025] in This indicates the mechanical power generated by the vehicle's traction system. Indicates the vehicle's traction or electric braking force. This indicates the vehicle's tare weight (including rotational mass) and load. Indicates the vehicle's acceleration. This indicates the vehicle's current resistance (including basic resistance, gradient resistance, curve resistance, etc.). This indicates the vehicle's mechanical braking force. This indicates the vehicle's current speed. Vehicle acceleration is limited by the traction system. At lower speeds, the maximum acceleration is a large, constant value. As the speed gradually increases, the maximum acceleration gradually decreases until it drops to 0.

[0026] Furthermore, the method for calculating the electrical power is as follows:

[0027] when hour:

[0028] ;

[0029] when hour:

[0030] ;

[0031] Indicates the vehicle's electrical power. This indicates the efficiency of the entire vehicle (from the DC bus to the wheel circumference) during traction. This indicates the efficiency of the entire vehicle (from wheel circumference to DC bus) during electric braking.

[0032] Furthermore, the energy storage device model includes operating condition judgment and power calculation. The operating condition judgment determines the operating condition of the energy storage device, which includes charging, discharging, and non-operating conditions. The upper limit of the energy ratio of the energy storage device is full charge or an energy ratio set manually considering the life cycle of the energy storage device. The lower limit of the remaining energy ratio of the energy storage device is 0% or a manually set value, and the remaining energy is not lower than the lower limit of the ratio. The power calculation is determined based on its own remaining energy, the contact network voltage, and the current position of the vehicle, and multiple preset strategies are automatically switched.

[0033] Furthermore, when the energy storage device is in discharge mode,

[0034] (1) When the vehicle is being towed:

[0035] Energy storage device discharge power = MIN{vehicle power - power of the power supply system at this node, maximum discharge power of the energy storage device};

[0036] The power of this node in the power supply system = vehicle traction power - energy storage device discharge power;

[0037] MIN{value1, value2} means taking the smaller of value1 and value2;

[0038] (2) When the vehicle is under electric braking or coasting: the discharge power of the energy storage device = 0;

[0039] When the energy storage device is in charging mode:

[0040] (1) When the vehicle is in traction: The energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current position. The power of the node in the power supply system = the charging power of the energy storage device + the power of the vehicle.

[0041] (2) When the vehicle is in regeneration: the energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current location. The power of the node in the power supply system = the charging power of the energy storage device - the power of the vehicle.

[0042] (3) When the vehicle is coasting: The energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current position. The power of the power supply system at this node = the charging power of the energy storage device;

[0043] When the energy storage device is not in operation: the power of the energy storage device is 0, and the power of the power supply system at this node is equal to the power of the vehicle.

[0044] The beneficial effects of this invention are as follows: This patent proposes a traction power supply calculation method applicable to electrified highways. Based on electrified highways, this method establishes a power supply model, a vehicle traction model, and an energy storage device model. During calculation, a transportation scheduling plan is established, driving parameters are configured, traction simulation, energy storage device operating condition judgment, power supply simulation, traction grid voltage assessment, rectifier unit calculation, and finally, the results are output to determine whether the vehicles, energy storage devices, and power supply system equipment meet the requirements. This method solves the dual-source power supply calculation problem in electrified highway power supply systems: including the power supply system simultaneously supplying power to operating vehicles and parked charging vehicles; vehicle operation relies on the coordinated power supply of the power supply system and the energy storage device. Attached Figure Description

[0045] To more clearly illustrate the specific embodiments of the present invention, the accompanying drawings used in the description of the specific embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0046] Figure 1 This is a schematic diagram of the electrified highway facilities and vehicle dispatching of the present invention;

[0047] Figure 2 A schematic diagram showing the connection relationship between the three models: power supply, vehicle traction, and energy storage device;

[0048] Figure 3 This is a schematic diagram of the electrified highway traction power supply model of the present invention;

[0049] Figure 4 This is a schematic diagram of the charging strategy for the energy storage device of the present invention;

[0050] Figure 5 This is a schematic diagram of the traction power supply calculation process of the present invention;

[0051] Figure 6 This is a schematic diagram of the simulation output results for an example. Detailed Implementation

[0052] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] This invention proposes a traction power supply calculation method applicable to electrified highways, such as... Figure 2 , Figure 3As shown, the method includes three models: a power supply model, a vehicle traction model, and an energy storage device. The power supply model includes a rectifier unit, a contact network, and a return line; the vehicle traction model includes the vehicle, the track, and the train; and the energy storage device model includes the charging and discharging power, efficiency, and stored energy of the energy storage device. The interface of the three modules is the DC bus on the vehicle. At any given time, the sum of the power of the three at that point is 0. During vehicle operation, energy flows between the power supply system, the vehicle traction system, and the energy storage device.

[0054] like Figure 5 As shown, this method includes the following steps:

[0055] Step 1: Based on the transportation task, establish a transportation scheduling plan and configure the driving parameters of all vehicles;

[0056] Step 2: Initialize the time, initialize the power supply model, vehicle traction model and energy storage device model input, set the cumulative calculation count to 1, and start the simulation;

[0057] Step 3: If it is the initial moment, set the entire network voltage to the rated voltage; otherwise, if the cumulative calculation count is 1, the network voltage setting is assigned according to the calculation result of the previous moment, otherwise it is assigned according to the calculation result of the previous moment.

[0058] Step 4: Traverse all vehicles, perform traction simulation, and calculate the power requirements of each vehicle.

[0059] Step 5: Iterate through all vehicle energy storage devices, determine operating conditions, and calculate power; if the remaining energy of the energy storage device is less than the lower limit of the remaining energy ratio, output "abnormal" and jump to step 9;

[0060] Step 6: Traverse all power supply systems, perform power supply simulation, and calculate the power of each rectifier unit, the current in the conductor, and the grid voltage at each node;

[0061] Step 7: Compare the relative values ​​of the calculated traction network voltage and the input network voltage. If the relative values ​​of all node network voltages are less than 1% or other preset values, proceed to step 9; otherwise, proceed to step 8.

[0062] Step 8: Determine the cumulative number of calculations at this moment. If it is less than 100 or other preset values, jump to step 3 and increment the cumulative number of calculations at this moment by 1. If the cumulative number of calculations is greater than 100 or other preset values, output "Abnormal" and jump to step 9.

[0063] Step 9: If there is no "abnormal" output at this moment, calculate the effective value of the rectifier power and the effective value of the conductor current within a certain period of time, and jump to step 10; otherwise, jump directly to step 10.

[0064] Step 10: If the simulation time is reached, proceed to step 11; otherwise, proceed to the next time step, set the cumulative calculation count to 1, and return to step 3.

[0065] Step 11: Output all results and determine whether the vehicle, energy storage device, and power supply system meet the requirements.

[0066] In step 1, the routes for electrified highway vehicles in the transportation scheduling plan are determined by transportation demand. When external transportation demand arises, transportation tasks are assigned to specific vehicles through bidding or assignment, forming the transportation scheduling plan. The organization of transportation on electrified highways is constrained by the capacity of the traction power supply system, vehicle energy storage devices, and freight yard loading and unloading arrangements, making transportation scheduling more complex. For example... Figure 1 As shown, Figure 1 (a) is a schematic diagram of electrified highway facilities. Figure 1 (b) is a diagram of vehicle dispatching. Figure 1 In a transportation area (a) containing 5 loading yards, 2 unloading yards and 2 charging yards, the following transportation scheduling plan is in place: Vehicle 1 needs to be charged first before loading and unloading, and after completing the transportation, it will continue to charge to prepare for the next transportation; after loading, Vehicle 2 will charge first because the energy storage device is not powerful enough, and then complete the transportation and unloading; after completing the transportation task, Vehicle 3 will return to the charging yard to charge.

[0067] Compared to traditional transportation scheduling, vehicle charging is an indispensable part of transportation scheduling on electrified highways. Generally, the power supply of the overhead contact system and the charging station on highways is coupled together. Therefore, it is necessary for the power supply system of electrified highways to consider the coordinated operation of vehicle charging and transportation processes.

[0068] The loading and unloading methods in the freight yard include: forklift loading and unloading, conveyor belt loading and unloading, loader loading and unloading, and pallet truck loading and unloading. At any given time, only a certain number of vehicles can be loaded and unloaded simultaneously. The departure interval of vehicles can be even or roughly even, or concentrated in certain periods due to weather or other factors. The total volume of each transport is uncertain, and the daily departure interval fluctuates.

[0069] In this embodiment, an electrified highway power supply model is established, consisting of a rectifier unit, a contact network, and a return line. This model includes the capacity and internal resistance of the rectifier unit, the cross-section and resistance of the contact network, and the cross-section and resistance of the return line. The power supply area is determined by the vehicle charging point and the start and end points of the contact network; other areas are areas without a contact network.

[0070] In electrified highways, vehicles are used for bulk cargo transportation (such as coal and minerals) and intercity freight. The power supply system needs to provide power to vehicles and energy storage devices when they are running and parked. The external power sources for the power supply system are diverse, generally 35 / 33kV, 10kV, etc., with output voltages typically 750V or 1500V. The power supply model established in this embodiment starts at the rectifier transformer inlet side. The interface between the power supply and the vehicles and energy storage devices is at the vehicle's DC bus. The rectifier transformer converts the high-voltage (35 / 33kV, 10kV) AC power from the external power source into low-voltage (750V or 1500V) DC power. In the power supply model, the rectifier unit is set as a voltage source; the vehicles and energy storage devices connected to the traction network and charging stations are set as power sources; and the contact network and return line are set as conductors.

[0071] The time period for power supply calculation is based on the period of the transportation scheduling plan, which can be 12 hours, 24 hours or other periods; the power supply calculation is based on the steady-state model, and the time interval can be 1 second, 2 seconds or other periods; at each time node, the power supply calculation can be performed using the node voltage method or the loop current method.

[0072] The power supply calculation results include the voltage of each node, the current on each cable, and the power of each rectifier unit. By processing the data at each time point, the effective value of the current of each conductor and the effective value of the power of the rectifier unit can be calculated.

[0073] Based on the calculation results, verify whether the design requirements are met: verify whether the grid voltage at any time point at the vehicle meets the vehicle's needs; verify whether the effective value of the current flowing through the conductor is lower than the conductor's current carrying capacity; verify whether the effective value of the rectifier unit is lower than the rectifier unit's capacity. An example of the judgment results is shown below:

[0074]

[0075] In this embodiment, an electrified highway vehicle traction model is established, consisting of a track, trains, and vehicles. This model simulates vehicle behavior within a section, including operating conditions, speed, position, and power. Departure intervals are based on the transportation organization plan, and vehicle loads change during loading and unloading. Vehicles operate flexibly: in areas with overhead contact lines, they travel along the contact line, using both the contact line and energy storage devices to power the vehicle, or using the contact line to power both the vehicle and the energy storage devices; in areas without contact lines, or during overtaking maneuvers, only the energy storage devices provide power. Each vehicle's route, load, and travel path can be defined independently.

[0076] Electrified highway vehicles are powered by dual sources. During operation, the vehicle is powered by both the overhead contact line and the energy storage device. In areas without an overhead contact line or with poor overhead contact line power quality, the vehicle is powered by its own energy storage device.

[0077] The inputs to the vehicle traction model are the route, vehicle, and travel: the route input includes stations, gradients, curves, and speed limits, used to calculate the vehicle's resistance and speed at various locations; the vehicle input includes the vehicle's weight (including rotational mass), acceleration, and efficiency, etc., with acceleration and efficiency determined by the traction system on the vehicle, which includes inverters, motors, transmissions, etc.; the travel input includes departure time, route (origin and destination), and load.

[0078] The vehicle's traction calculations begin with its departure from the charging station and its current position as the initial condition. Vehicle traction includes loading, en route transportation, unloading, and other necessary processes. The load varies depending on the process. Vehicle traction is calculated based on the vehicle's operating state, determining the mechanical and electrical power generated by the traction system.

[0079] The method for calculating mechanical power is as follows:

[0080] ;

[0081] in This indicates the mechanical power generated by the vehicle's traction system. Indicates the vehicle's traction or electric braking force. This indicates the vehicle's tare weight (including rotational mass) and load. Indicates the vehicle's acceleration. This indicates the vehicle's current resistance (including basic resistance, gradient resistance, curve resistance, etc.). This indicates the vehicle's mechanical braking force. This indicates the vehicle's current speed. Vehicle acceleration is limited by the traction system. At lower speeds, the maximum acceleration is a large, constant value. As the speed gradually increases, the maximum acceleration gradually decreases until it drops to 0.

[0082] The method for calculating electric power is as follows:

[0083] when hour:

[0084] ;

[0085] when hour:

[0086] ;

[0087] Indicates the vehicle's electrical power. This indicates the efficiency of the entire vehicle (from the DC bus to the wheel circumference) during traction. This indicates the efficiency of the entire vehicle (from wheel circumference to DC bus) during electric braking.

[0088] In this embodiment, an electrified highway energy storage device model is established, based on the energy storage device's power, remaining energy, and upper and lower proportional limits. The model controls the energy storage device's operating conditions and calculates its power and remaining energy. The energy storage device model has multiple charging strategies and can calculate its own charging power based on voltage, its own remaining energy, and vehicle location. The energy storage device model possesses general charging and discharging characteristics and energy change formulas. Figure 4 As shown, a schematic diagram of a possible charging strategy for an energy storage device is provided. The rated voltage of the power supply system is 750V, and the maximum charging power of the energy storage device is 500kW. Different colors represent different remaining energy of the energy storage device.

[0089] The energy storage device model includes: energy storage device power, energy storage device remaining energy and proportional upper limit, proportional lower limit, operating condition judgment and power calculation.

[0090] Energy storage device operating condition judgment is to determine which operating condition the energy storage device is in. There are three types of energy storage device operating conditions: charging condition, discharging condition, and non-operating condition.

[0091] When the vehicle is parked, the following criteria are applied sequentially: if the battery level has not reached the upper limit of the energy ratio and the vehicle can be charged, it is set to charging mode; otherwise, it is set to discharging mode.

[0092] When the vehicle is in motion, the following criteria shall be applied sequentially:

[0093] ① When the battery level reaches the upper limit of the energy ratio and the vehicle is coasting or in electric braking mode, the energy storage device is set to non-working mode.

[0094] ②When the battery level is below the maximum energy ratio and the vehicle is coasting, the energy storage device is set to charging mode;

[0095] ③ When the battery charge has not reached the upper limit of the energy ratio and the vehicle is in electric braking mode, the energy storage device is set to charging mode.

[0096] ④ When the power exceeds the lower limit of the energy ratio and the vehicle is in traction condition, the vehicle is located without contact wire or the traction wire voltage is less than the rated voltage, and the energy storage device is set to discharge condition.

[0097] ⑤ When the power exceeds the lower limit of the energy ratio and the vehicle is in traction mode, and the traction network voltage is greater than or equal to the preset traction network voltage (such as the rated voltage), the energy storage device is set to charging mode.

[0098] ⑥ Other: Energy storage devices are set to non-operating conditions.

[0099] The energy storage device should not have any remaining energy below the lower limit of the ratio. The lower limit of the remaining energy ratio of the energy storage device can be 0% or a manually set value, such as 20%. The charging power calculation of the energy storage device is determined based on its own remaining energy, the overhead contact line voltage, and the current location of the vehicle, etc. Multiple preset strategies can be used and switched automatically.

[0100] (1) When the energy storage device is in discharge mode,

[0101] ①When the vehicle is being towed:

[0102] Energy storage device discharge power = MIN{vehicle power - power of the power supply system at this node, maximum discharge power of the energy storage device};

[0103] The power of this node in the power supply system = vehicle traction power - energy storage device discharge power;

[0104] MIN{value1, value2} means taking the smaller of value1 and value2.

[0105] ②When the vehicle is under electric braking or coasting: the energy storage device discharge power = 0;

[0106] (2) When the energy storage device is in charging mode:

[0107] ① When the vehicle is being towed: The energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current position. The power of the power supply system at this node = the charging power of the energy storage device + the power of the vehicle.

[0108] ② When the vehicle is in regeneration: The energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current location. The power of the power supply system at this node = the charging power of the energy storage device - the power of the vehicle.

[0109] ③ When the vehicle is coasting: The energy storage device determines the charging power based on the remaining energy of the energy storage device, the node voltage and the current position. The power of the power supply system at this node is equal to the charging power of the energy storage device.

[0110] (3) When the energy storage device is not in operation: the power of the energy storage device is 0, and the power of the power supply system at this node is equal to the power of the vehicle.

[0111] For vehicle energy storage devices The power at any given moment can be denoted as .

[0112] Alternatively, power can be calculated using ammeters and voltmeters: The current at time is The voltage is .

[0113]

[0114] Remaining energy of energy storage devices The power at this moment and the remaining energy at the previous moment Sure.

[0115] hour:

[0116]

[0117] This indicates the charging efficiency of the charging device. Indicates a unit of time.

[0118] hour:

[0119]

[0120] This indicates the discharge efficiency of the charging device.

[0121] The simulation input for this embodiment is as follows:

[0122] In the power supply model, the inputs include the rectifier unit capacity, the contact wire cross-section and resistance, and the return line cross-section and resistance.

[0123] In the traction model, the inputs include: track (depot location, gradient, curve and speed limit), vehicle (acceleration, efficiency, weight), and driving (departure time, origin and destination, load).

[0124] In the energy storage device model, the inputs include: the power, capacity, upper limit of the proportional ratio, and lower limit of the proportional ratio of the energy storage device.

[0125] The simulation results output through steps 1-11 are as follows: The calculation results include the load current-time curve of the rectifier unit in the power supply system, the conductor current-time curve, the contact network voltage-time curve, and the vehicle's operating data, including the vehicle's position, speed, acceleration, mechanical power, electrical power-time curve, the current-time curve between the vehicle and the contact network, the power of the energy storage device, and the remaining energy-time curve, such as... Figure 6 As shown, the vehicle operates on a DC 750V system and mainly experiences the following events:

[0126] (1) The vehicle starts charging at minute 0 and ends charging at minute 20;

[0127] (2) The vehicle starts at 20 minutes and accelerates to 60 km / h at 22 minutes. The vehicle is powered by both the overhead contact line and the energy storage device.

[0128] (3) From the 22nd minute to the 60th minute, the traction network voltage is high, and the vehicle relies solely on the overhead contact line for power supply;

[0129] (4) Between the 60th and 65th minute, the traction net is lowered, and the vehicle relies on the contact net and energy storage device for power supply;

[0130] (5) The vehicle operates in the power-free zone from the 65th to the 70th minute, and the vehicle relies on the energy storage device for power supply;

[0131] (6) Between the 70th and 75th minute, the traction net is lowered, and the vehicle relies on the contact net and energy storage device for power supply;

[0132] (7) Between the 75th and 90th minutes, the traction network voltage is high, and the vehicle relies on the overhead contact line for power supply;

[0133] (8) Between the 90th and 92nd minutes, the vehicle slows down until it comes to a stop;

[0134] (9) The vehicle is charged between the 92nd and 100th minute.

[0135] All intermediate parameters of the simulation model established by this invention can be selected for output, for verification of calculation results, or for other purposes.

[0136] The present invention has been described in detail above through embodiments, but the content is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the patent coverage of the present invention.

Claims

1. A calculation method for traction power supply applicable to electrified highways, characterized in that: The calculation method includes a power supply model, a vehicle traction model, and an energy storage device model. The power supply model includes a rectifier unit, a contact network, and a return line. The vehicle traction model includes vehicles, tracks, and traffic flow. The energy storage device model includes the charging and discharging power, efficiency, and stored energy of the energy storage device. In the calculation of traction power supply for electrified highways, the interface between the power supply model, the vehicle traction model, and the energy storage device model is the vehicle's DC bus. At any given time, the sum of the power of the three at that point is 0. The method specifically includes the following steps: Step 1: Based on the transportation task, establish a transportation scheduling plan and configure the driving parameters of all vehicles; Step 2: Initialize the time, initialize the input of the power supply model, vehicle traction model and energy storage device model, set the cumulative calculation count to 1, and start the simulation; Step 3: If it is the initial moment, set the entire network voltage to the rated voltage; otherwise, if the cumulative calculation count is 1, the network voltage setting is assigned according to the calculation result of the previous moment, otherwise it is assigned according to the calculation result of the previous moment. Step 4: Traverse all vehicles, perform traction simulation, and calculate the power requirements of each vehicle; Step 5: Iterate through all vehicle energy storage devices, determine operating conditions, and calculate power; if the remaining energy of the energy storage device is less than the lower limit of the remaining energy ratio, output "abnormal" and jump to step 9; Step 6: Traverse all power supply systems, perform power supply simulation, and calculate the power of each rectifier unit, the current in the conductor, and the grid voltage at each node; Step 7: Compare the relative values ​​of the calculated traction network voltage and the input network voltage. If the relative values ​​of all node network voltages are less than 1% or other preset values, proceed to step 9; otherwise, proceed to step 8. Step 8: Determine the cumulative number of calculations at this moment. If it is less than 100 or other preset values, jump to step 3 and increment the cumulative number of calculations at this moment by 1. If the cumulative number of calculations is greater than 100 or other preset values, output "Abnormal" and jump to step 9. Step 9: If there is no "abnormal" output at this moment, calculate the effective value of the rectifier power and the effective value of the conductor current within a certain period of time, and jump to step 10; otherwise, jump directly to step 10. Step 10: If the simulation time is reached, proceed to step 11; otherwise, proceed to the next time step, set the cumulative calculation count to 1, and return to step 3. Step 11: Output all results and determine whether the vehicle, energy storage device, and power supply system meet the requirements.

2. The traction power supply calculation method applicable to electrified highways according to claim 1, characterized in that: In step 1, the electrified highway vehicle operation routes in the transportation scheduling plan are determined by transportation demand. When external transportation demand occurs, transportation tasks are assigned to specific vehicles through bidding or assignment, thus forming a transportation scheduling plan.

3. The traction power supply calculation method applicable to electrified highways according to claim 1, characterized in that: The power supply system of the power supply model supplies power to both the operating vehicles and the parked charging vehicles. The operation of the vehicles relies on the coordinated power supply of the power supply system and the energy storage device. The time period for power supply calculation is based on the period of the transportation scheduling plan, which is 12 hours, 24 hours or other. The power supply calculation is based on the steady-state model, and the time interval is 1 second, 2 seconds or other.

4. The traction power supply calculation method applicable to electrified highways according to claim 1, characterized in that: When the vehicle traction model is calculated, the vehicle starts from leaving the charging device and uses its current position as the initial condition for traction calculation. The vehicle traction is calculated based on the vehicle's operating state, determining the mechanical and electrical power generated by the vehicle traction system. The mechanical power calculation method is as follows: ； ； in This indicates the mechanical power generated by the vehicle's traction system. Indicates the vehicle's traction or electric braking force. This indicates the vehicle's tare weight and load. Indicates the vehicle's acceleration. This indicates the current resistance of the vehicle. This indicates the vehicle's mechanical braking force. This indicates the vehicle's current speed.

5. The traction power supply calculation method applicable to electrified highways according to claim 4, characterized in that: The method for calculating the electrical power is as follows: when hour: ； when hour: ； Indicates the vehicle's electrical power. This indicates the efficiency of the entire vehicle's DC bus to the wheel circumference during traction. This indicates the efficiency of the entire wheel circumference to the DC bus during electric braking.

6. The traction power supply calculation method applicable to electrified highways according to claim 1, characterized in that: The energy storage device model includes operating condition judgment and power calculation. The operating condition judgment determines the operating condition of the energy storage device, which includes charging, discharging, and non-operating conditions. The upper limit of the energy ratio of the energy storage device is full charge or an energy ratio set manually considering the life cycle of the energy storage device. The lower limit of the remaining energy ratio of the energy storage device is 0% or a manually set value, and the remaining energy is not lower than the lower limit of the ratio. The power calculation is determined based on its own remaining energy, the contact network voltage, and the current position of the vehicle, and multiple preset strategies are automatically switched.

7. The traction power supply calculation method applicable to electrified highways according to claim 6, characterized in that: When the energy storage device is in discharge mode (1) When the vehicle is being towed: Energy storage device discharge power = MIN{vehicle power - power of the power supply system at this node, maximum discharge power of the energy storage device}; The power of this node in the power supply system = vehicle traction power - energy storage device discharge power; MIN{value1, value2} means taking the smaller of value1 and value2; (2) When the vehicle is under electric braking or coasting: the discharge power of the energy storage device = 0; When the energy storage device is in charging mode: (1) When the vehicle is being towed: The energy storage device determines its charging power based on its remaining energy, the grid voltage at the node, and its current location. The power of this node in the power supply system = charging power of the energy storage device + vehicle power. (2) When the vehicle is in the process of regeneration: The energy storage device determines its charging power based on its remaining energy, grid voltage, and current location. The power of this node in the power supply system is equal to the charging power of the energy storage device minus the vehicle power. (3) When the vehicle is coasting: The energy storage device determines its charging power based on its remaining energy, the grid voltage at the node, and its current location. The power of this node in the power supply system equals the charging power of the energy storage device. When the energy storage device is not in operation: The energy storage device has a power of 0, and the power of this node in the power supply system equals the vehicle's power.

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