System, method and apparatus for simulating grid-side harmonics of multiple grid-connected rail vehicles

Abstract

Embodiments of the present application provide a system, method and apparatus for simulating grid-side harmonics of multiple grid-connected rail vehicles. The system comprises an superordinate computer, a simulator, and a signal distribution system; the superordinate computer is used for sending a rail transit power supply system simulation model to the simulator, and receiving a real-time running state returned by the simulator; the simulator is used for receiving and running the simulation model, and generating a corresponding simulation input signal; and the signal distribution system is used for sending the simulation input signal to a plurality of physical control units on the basis of a preset rule, and sending, to the simulator, simulation output signals returned by the plurality of physical control units, so that the simulator returns the real-time running state to the superordinate computer on the basis of the simulation output signals.

Description

Simulation System, Method and Apparatus for Simulating Harmonic Waves on the Grid Side of Multiple Rail Vehicles Connected to the Grid

[0001] Related applications

[0002] This application claims priority to Chinese Patent Application No. 202510362907.0, filed on March 26, 2025, and incorporates the disclosure of the aforementioned patent application as part of this application. Technical Field

[0003] This application relates to the field of rail transit vehicle-to-grid electrical systems, specifically to a simulation system, method, and apparatus for simulating harmonics on the grid side of multiple rail vehicles connected to the grid. Background Technology

[0004] During railway transportation, due to the short train departure intervals and the fact that the length of a single power supply arm in the 25kV power supply network can reach 10 to 20 kilometers, different types of EMU trains often operate simultaneously under the same power supply arm. This multi-car grid operation mode easily leads to a sharp increase in high-frequency harmonics in the traction network.

[0005] When the harmonic frequency coincides with the impedance frequency of the resonant circuit formed by the traction network and the EMU (Electric Multiple Unit), resonance problems will occur. This makes EMUs in harsh environments under the power supply arm (usually the trains farthest from the power supply station) highly susceptible to faults with excessively high grid voltage peaks, endangering train operation safety. Since the traction converter is often the excitation source of resonance, in order to verify the effect of the converter control algorithm on harmonic suppression, it is necessary to simulate the high-frequency harmonic operation of the grid side of multiple trains connected to the grid.

[0006] Current testing methods include real-vehicle field testing and fully digital simulation testing; however, both of these methods have significant drawbacks.

[0007] First, real-vehicle testing consumes a significant amount of manpower, resources, and capital, has a long testing cycle, and is difficult to accurately simulate specific operating conditions. While fully digital simulation testing can simulate high-frequency resonance phenomena, its non-real-time nature and limited server computing power result in excessively long testing wait times.

[0008] Meanwhile, the traction system controller operates in a fully digital environment, making it impossible to verify the performance of the actual controller, resulting in significant discrepancies between simulation results and real-world operation. These issues limit the effectiveness of existing technologies in verifying harmonic suppression algorithms. Summary of the Invention

[0009] To address the problems in the prior art, this application provides a simulation system, method, and apparatus for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, which can simulate the connection of multiple vehicles to the grid and be used to study the performance of harmonic suppression algorithms.

[0010] To solve at least one of the above problems, this application provides the following technical solution:

[0011] According to a first aspect of the embodiments of this application, this application provides a simulation system for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, including a host computer, a simulator, and a signal distribution system;

[0012] The host computer is used to send the simulation model of the rail transit power supply system to the simulator and receive the real-time operating status returned by the simulator.

[0013] The simulator is used to receive and run the simulation model and generate corresponding simulation input signals, including voltage and current analog signals, digital feedback signals and speed encoder signals.

[0014] The signal distribution system is used to send the simulation input signal to multiple physical control units based on preset rules, and to send the simulation output signal returned by the multiple physical control units to the simulator, so that the simulator returns the real-time running status to the host computer according to the simulation output signal. The simulation output signal includes control pulse signal and digital control signal.

[0015] According to a second aspect of the embodiments of this application, this application provides a simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to a grid, applied to a simulator, comprising:

[0016] Obtain a simulation model of the rail transit power supply system. The simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model.

[0017] The simulation input signal is generated according to the simulation model, and the simulation input signal is sent to multiple physical control units according to preset rules through the signal distribution system. The simulation input signal includes voltage and current analog signals, digital feedback signals and speed encoder signals.

[0018] The simulation output signals returned by multiple physical control units are acquired, and the real-time operating status is returned to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0019] According to a third aspect of the embodiments of this application, this application provides a simulation device for simulating harmonics on the grid side of multiple-vehicle parallel rail vehicles, applied to a simulator, comprising:

[0020] The model acquisition module is used to: acquire a simulation model of the rail transit power supply system, wherein the simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model;

[0021] The simulation operation module is used to: generate corresponding simulation input signals according to the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals.

[0022] The status feedback module is used to: acquire simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0023] According to a fourth aspect of the embodiments of this application, this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid.

[0024] According to a fifth aspect of the embodiments of this application, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid.

[0025] According to a sixth aspect of the embodiments of this application, this application provides a computer program product, including a computer program / instructions, which, when executed by a processor, implement the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid.

[0026] As can be seen from the above technical solution, this application provides a simulation system, method, and apparatus for simulating harmonics on the grid side of multiple rail vehicles connected to the grid. The system includes a host computer, a simulator, and a signal distribution system. The host computer sends a simulation model of the rail transit power supply system to the simulator and receives the real-time operating status returned by the simulator. The simulator receives and runs the simulation model and generates corresponding simulation input signals. The signal distribution system sends the simulation input signals to multiple physical control units based on preset rules and sends the simulation output signals returned by the multiple physical control units to the simulator, so that the simulator returns the real-time operating status to the host computer based on the simulation output signals. This allows for the simulation of multiple vehicles connected to the grid, which can be used to study the performance of harmonic suppression algorithms. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 is one of the schematic diagrams of a simulation system for simulating harmonics on the grid side of multiple rail vehicles connected to the grid in an embodiment of this application.

[0029] Figure 2 is a second schematic diagram of the simulation system for simulating harmonics on the grid side of multiple rail vehicles connected to the grid in this application embodiment.

[0030] Figure 3 is a schematic diagram of the network compression calculation model in the embodiments of this application.

[0031] Figure 4 is an equivalent topology diagram of the main traction circuit of the EMU in the embodiment of this application.

[0032] Figure 5 is a schematic diagram of the DC circuit model in an embodiment of this application.

[0033] Figure 6 is an equivalent topology diagram of the inverter circuit in the embodiment of this application.

[0034] Figure 7 is a schematic diagram of the inverter model and the asynchronous motor model in the embodiments of this application.

[0035] Figure 8 is a flowchart of the simulation system method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid in the embodiments of this application.

[0036] Figure 9 is a structural diagram of the simulation device for simulating harmonics on the grid side of multiple rail vehicles connected to the grid in an embodiment of this application. Detailed Implementation

[0037] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0038] The acquisition, storage, use, and processing of data in this application comply with relevant laws and regulations.

[0039] Considering that current testing methods include on-site vehicle testing and fully digital simulation testing, both of which have significant drawbacks, this application provides a simulation system, method, and apparatus for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, thereby simulating the operation of multiple vehicles connected to the grid and studying the performance of harmonic suppression algorithms.

[0040] In order to simulate the multi-vehicle grid connection and study the performance of harmonic suppression algorithms, this application provides an embodiment of a simulation system for simulating the harmonics on the grid side of the multi-vehicle grid connection of rail vehicles, as shown in Figure 1, including a host computer 01, a simulator 02 and a signal distribution system 03.

[0041] The host computer 01 is used to send the simulation model of the rail transit power supply system to the simulator and receive the real-time operating status returned by the simulator.

[0042] Simulator 02 is used to receive and run simulation models and generate corresponding simulation input signals, including analog voltage and current signals, digital feedback signals, and speed encoder signals.

[0043] The signal distribution system 03 is used to send the simulation input signal to multiple physical control units (such as vehicle traction controllers) based on preset rules, and to send the simulation output signals returned by the multiple physical control units to the simulator, so that the simulator can return the real-time running status to the host computer according to the simulation output signal. The simulation output signal includes control pulse signal and digital control signal.

[0044] For example, after receiving the real-time operating status, the host computer 01 can determine the operating index data based on the real-time operating status, compare the operating index data with the corresponding safety threshold, and if the operating index data meets the safety threshold requirements, the host computer 01 sends a confirmation command to the physical control unit. The physical control unit stores the operating parameters corresponding to the previous simulation and controls the actual operation of the rail vehicle based on these operating parameters. Specifically, the real-time operating status may include data corresponding to the operating indicators, or data used to calculate the operating indicators; this specification does not limit this.

[0045] Among them, the host computer 01 serves as the control center of the system, responsible for loading and sending the simulation model of the rail transit power supply system to the simulator, while receiving the real-time operating status data returned by the simulator.

[0046] In an optional embodiment, the simulation model includes one or any combination of the following models:

[0047] Including the network compression calculation model;

[0048] Four-quadrant pulse rectifier model;

[0049] Traction transformer model;

[0050] Pre-charge model;

[0051] Four-quadrant rectifier model;

[0052] DC loop model;

[0053] Inverter model;

[0054] Asynchronous motor model.

[0055] After receiving simulation output signals from multiple physical control units, simulator 02 dynamically adjusts the operating parameters of the simulation model based on real-time calculated voltage, current, traction load, and other status information, ensuring that the simulation state of the rail transit power supply system closely matches actual operating conditions. For example, when multiple train sets operate simultaneously under the same power supply arm, the simulator simulates the power demand of each train, the converter's operating state, and its harmonic impact on the power supply network. It also coordinates the electrical interactions of each traction controller through signal distribution system 03, ensuring that the system accurately reproduces the complex electromagnetic environment of multi-train parallel operation.

[0056] Among them, the analog voltage and current signals are used to provide simulated voltage and current information to the physical control unit, enabling the control unit to receive input under real operating conditions and make corresponding control adjustments.

[0057] Control pulse signals are used to transmit PWM (Pulse Width Modulation) or other types of control pulses to physical control units, enabling them to drive power electronic devices (such as IGBT inverters or rectifiers). They are typically used to control motor speed, rectifier conduction status, etc.

[0058] Digital feedback signals are used to send specific control commands from the simulation system to the physical control unit, such as start / stop commands and mode switching signals.

[0059] Digital control signals are used to return data from the physical control unit to the simulation system to provide real-time operating status of the equipment, such as contactor switch status and converter operating mode.

[0060] The speed encoder signal is used to provide simulated speed feedback information so that the physical control unit can adjust the control strategy based on the speed data.

[0061] During closed-loop control, simulator 02 continuously analyzes and adjusts the outputs of each traction controller. For example, when a train's converter generates a high-frequency harmonic current, the simulator simulates how this harmonic propagates through the traction network based on the simulation model and calculates its impact on other trains under the same power supply arm. Simultaneously, the simulator updates the grid voltage calculation model, four-quadrant rectifier model, traction transformer model, etc., based on the real-time operating status of different vehicles, to accurately reflect the harmonic characteristics of rail vehicles under different operating conditions.

[0062] Finally, after receiving the real-time operating status returned by the simulator 02, the host computer 01 performs a visual analysis of the harmonic distribution of the entire power supply system and optimizes the harmonic suppression effect by adjusting the converter control algorithm.

[0063] For example, if harmonic exceedances are found under a specific operating mode, the PWM modulation strategy of the converter, the filter circuit, or the transformer parameters can be adjusted in the simulation environment to verify the actual performance of different harmonic suppression algorithms. In this way, the system of this application achieves accurate simulation of multi-vehicle grid-connected operation, providing a high-precision simulation environment for the research of harmonic suppression algorithms, thereby optimizing the stability of the rail transit traction power supply system, improving power quality, and reducing power supply failures or equipment damage caused by harmonic problems.

[0064] In this process, the signal distribution system 03 acts as a distribution bridge, responsible for distributing the simulation input signal to multiple physical control units according to preset rules. At the same time, it receives the simulation output signals returned by these controllers, including control pulse signals and digital control signals, and sends them back to the simulator to form a closed-loop simulation control process.

[0065] In an optional embodiment, as shown in FIG2, the signal distribution system includes a signal distribution unit and a signal conditioning unit;

[0066] The signal distribution unit is used to distribute the simulation input signals according to preset rules and send the simulation output signals returned by multiple physical control units to the simulator;

[0067] The signal conditioning unit is used to send the distributed simulation input signals to multiple physical control units; and

[0068] The simulation input signals are converted to an input format compatible with the physical control unit, and the simulation output signals are converted to an input format compatible with the simulator.

[0069] For example, the core task of the signal distribution unit is to distribute the simulated input signals generated by the simulator to multiple physical control units based on preset rules. For instance, in an operating environment, if four train sets are operating simultaneously under the power supply arm, the signal distribution unit distributes the signals specifically according to the operating parameters of each train set (such as position, load, and speed) to ensure that each train set receives its own dedicated input signal.

[0070] At the same time, the signal distribution unit collects the simulation output signals generated by each physical control unit, such as control pulse signals and digital feedback signals, and integrates these signals before sending them back to the simulator to update the running status of the simulation model in real time.

[0071] The signal conditioning unit primarily addresses the matching of signal format, level, and frequency. For example, if a physical control unit can only receive 5V digital signals, while the emulator generates a 3.3V signal, the signal conditioning unit will convert the 3.3V signal to a 5V signal.

[0072] Similarly, for the simulated output signal returned by the physical control unit, if the signal frequency is high and contains high-frequency noise, the signal conditioning unit will first filter the signal and then adjust it to an input format acceptable to the simulator. For example, the PWM signal output by the inverter can be conditioned into a continuous signal waveform required by the simulator.

[0073] In a specific, exemplary scenario, suppose multiple train sets operate simultaneously under a single power supply arm. The input signals generated by the simulator need to be distributed to the traction controllers of these train sets. The signal distribution unit allocates different current and voltage signals according to the train sets' operating positions (e.g., train 1 at the front of the power supply arm, train 2 in the middle, and train 3 at the rear) and load conditions (e.g., train 1 fully loaded, train 3 unloaded). Simultaneously, the signal conditioning unit adapts the signal returned from train 1 and sends it to the simulator to update the load parameters in the grid voltage calculation model, thereby simulating the actual impact of train 1 on the power supply system in real time.

[0074] In an optional embodiment, referring to Figure 2, the simulator is the hardware foundation for the simulation model to run and interact with the physical traction control unit for process data. The real-time simulator is equipped with relevant CPU boards, FPGA boards, DIO interface boards, etc. The signals are matched with the physical traction control unit through the signal distribution unit and the signal conditioning system to achieve the required simulation requirements in combination with the developed model.

[0075] Optionally, the simulation monitoring computer is equipped with TRDP and MVB communication boards (host computer) and runs train network simulation software. The software forms a communication closed loop with the physical traction control unit by importing the actual vehicle communication protocol.

[0076] For example, the real-time simulator and the simulation monitoring computer are connected via Ethernet, facilitating the operation and observation of the simulation process through the real-time simulation software on the simulation monitoring computer. Preferably, the simulation model is developed based on modular graphical programming tools such as System Generator, and the electrical model is converted into a real-time application using a matching compilation tool. The program code runs on the FPGA of the real-time simulator platform, with an operation frequency of up to 10MHz.

[0077] The FPGA board for the simulator is mainly used to run real-time models of systems such as substations, overhead contact lines, pantographs, train main transformers, traction converters, and traction motor loads. The real-time model's solution signals interact with the controller through a signal distribution unit, forming a control closed loop.

[0078] In an optional embodiment, the grid voltage calculation model is used to characterize the voltage and current states of the transformer under no-load, short-circuit, and load operating conditions by the electrical parameter relationship between the primary and secondary sides of the transformer.

[0079] The 25kV grid voltage is output by the substation output transformer. The output transformer is mainly divided into three operating conditions: no-load, short-circuit, and load operation. The first two can be regarded as two specific situations of transformer load operation.

[0080] Under no-load conditions, the secondary current of the transformer is set to zero; under short-circuit conditions, the load of the transformer is set to zero. Table 1 is a description of the input and output parameters of the grid voltage calculation module, and Figure 3 is a schematic diagram of the grid voltage calculation model of this application. In this model, the load operation condition of the transformer is taken as an example, and the following transformer mathematical formulas are the basis for modeling.

[0081] Wherein, U1: transformer primary voltage, that is, the input voltage applied by the power supply network to the transformer primary side.

[0082] I1: Transformer primary current, including load current and magnetizing current.

[0083] R1: Transformer primary resistance, representing the resistance value of the transformer primary winding.

[0084] L1: Transformer primary inductance, representing the inductive characteristics of the primary winding.

[0085] U m : Transformer excitation voltage, representing the induced voltage caused by the excitation current ImI_mIm.

[0086] I m Transformer excitation current: This refers to the current used to generate the magnetic field of the transformer.

[0087] R mThe excitation resistance of a transformer represents its resistance characteristics related to the excitation current.

[0088] L m The magnetizing inductance of a transformer represents the inductive characteristic of the change in magnetic flux caused by the magnetizing current.

[0089] k: Transformer turns ratio, representing the ratio of the number of turns in the primary winding to the number of turns in the secondary winding.

[0090] U2: Secondary voltage of the transformer, that is, the voltage output from the secondary side of the transformer.

[0091] I2: Transformer secondary current, representing the secondary load current.

[0092] R2: Transformer secondary resistance, representing the resistance value of the transformer secondary winding.

[0093] The above formula can be transformed into:

[0094] To build the discretized model of the above formula, the Tustin transform needs to be used to discretize the transfer function.

[0095] Table 1

[0096] Preferably, the substation grid voltage calculation parameters of this application are: R1 = 4.3218; L1 = 0.45856; R2 = 0.7938; L2 = 0.00802; R m =1.0805e+006; L m =2866; T s =1e-7.

[0097] In summary, the grid voltage calculation model accurately simulates the voltage and current variation characteristics of transformers in rail transit power supply systems under three typical operating conditions: no-load, short-circuit, and load operation, by establishing the electrical parameter relationship between the primary and secondary sides of the transformer. This improves the simulation accuracy of the dynamic response of the power supply system. For example, when high-speed trains operate simultaneously on the same power supply arm, fluctuations in traction load may lead to grid voltage instability. This model can effectively capture voltage drops or harmonic resonance phenomena under different load conditions, thus providing accurate simulation data for the optimized design of the traction controller.

[0098] In an optional embodiment, a four-quadrant pulse rectifier model is used to characterize the DC loop current state by the electrical relationship between the rectifier output current and the total load current.

[0099] As shown in Figure 4, the topology diagram of the main traction circuit of the EMU shows that the DC circuit current is equal to the output current of the four-quadrant pulse converter minus the converter load current. Therefore, the intermediate circuit receives the total load current. The intermediate circuit load includes the traction motor and auxiliary system, so the total load current is the sum of the load currents of the traction motor and auxiliary power supply. Therefore, the formula for calculating the DC circuit current is: i dc =i o1 -i load_sum (4)

[0100] Among them, i o1 i represents the output current of the four-quadrant pulse converter. load_sum This represents the total load current.

[0101] In summary, the four-quadrant pulse rectifier model can simulate the dynamic changes in DC circuit current in rail transit traction systems. When high-speed trains operate in multi-car grid interconnection, it helps analyze the relationship between the rectifier's output current, the traction motor load current, and the auxiliary power supply load current. By calculating the total rectifier output current and combining it with feedback from the total load current, the real-time power demand of the traction system can be accurately reflected. For example, when the train accelerates, the traction motor load current rises rapidly, while auxiliary systems (such as air conditioning and electrical control systems) maintain a constant load. The rectifier needs to adjust its output current according to demand to ensure the stability of the DC bus.

[0102] In an optional embodiment, the traction transformer model is used to characterize the level transition state of the transformer in the rail transit traction system by establishing the parametric relationship between the primary and secondary sides of the transformer.

[0103] The traction transformer is a crucial component of the high-voltage system, enabling level transformation of the traction power supply. In the system, the traction transformer model is upstream of the traction main circuit model, providing input voltage to the main circuit breaker and converter models; and downstream of the pantograph-catenary current collection model.

[0104] In summary, the traction transformer model, by simulating the level transformation characteristics of the traction transformer in a rail transit power supply system, accurately represents the electrical relationship between the power supply network and the traction load. In high-speed rail and intercity rail transit systems, the main function of the traction transformer is to convert 25kV high-voltage AC power into a voltage suitable for the traction system and provide a stable input power supply to the traction converter.

[0105] Based on the electrical parameter relationship between the primary and secondary sides, this model can effectively simulate the voltage and current changes of a transformer under different load conditions. For example, when multiple EMU trains operate simultaneously under the same power supply arm, the traction transformer faces different load demands. This model can dynamically adjust the simulation parameters to evaluate whether the transformer's output voltage meets the power supply requirements of all EMU trains.

[0106] In an optional embodiment, the pre-charge model is used to characterize the pre-charge state of the traction converter during the initial power-on process by simulating the circuit structure of the pre-charge contactor, main contactor, filter capacitor, filter resistor, current-limiting resistor and LC filter.

[0107] The pre-charge circuit is an essential sub-circuit in the converter system, designed to prevent excessive DC bus current surges when the power is initially switched on. Its model represents the front end of the traction converter model and primarily consists of a charging contactor, main contactor, filter capacitor, filter resistor, current-limiting resistor, and LC filter circuitry.

[0108] K and Q are contactor switches; 1 is when closed and 0 is when open.

[0109] K is the pre-charging contactor, and Q is the short-circuiting contactor. These two contactors receive signals from the controller and operate accordingly.

[0110] For example, when a rail vehicle starts, the DC bus capacitor of the traction converter needs to be charged. If the circuit is closed directly, it may cause a large instantaneous current to flow in, leading to equipment damage or grid fluctuations. This model precisely controls the pre-charging process by introducing a pre-charging contactor, main contactor, filter capacitor, current-limiting resistor, and LC filter. For instance, when the train is first powered on, the pre-charging contactor K closes first, allowing current to gradually charge the bus capacitor through the current-limiting resistor. Once the voltage reaches the set value, the short contactor Q closes, bypassing the current-limiting resistor, allowing the system to enter a stable operating state. This model can accurately simulate the current and voltage changes during pre-charging, providing a reliable simulation environment for optimizing the converter's start-stop logic. Furthermore, it can be used to analyze pre-charging strategies under different voltage levels and capacitor configurations, helping to optimize the design of the traction power supply system and ensuring the safe start-up of the train under various operating conditions.

[0111] In an optional embodiment, the four-quadrant rectifier model is used to characterize the operating state of a single-phase two-level four-quadrant rectifier in the process of converting AC power to DC power by simulating the circuit structure of a single-phase two-level four-quadrant rectifier composed of IGBT half-bridge modules.

[0112] The four-quadrant rectifier model simulates the AC-DC conversion process in a rail transit traction system, enabling simulation of the bidirectional energy flow characteristics of the converter and improving the system's adaptability and control accuracy under different operating conditions. This model employs a two-IGBT half-bridge splicing structure. Working in conjunction with the pre-charge model, this model ensures a smooth start-up of the converter during initial power-on, and in conjunction with the DC loop model, achieves a complete simulation of the traction power supply system.

[0113] In an optional embodiment, the DC loop model is used to characterize the electrical state of the DC bus in the rail vehicle traction system by establishing the electrical parameter relationships of the filter capacitor, filter inductor, current-limiting resistor, and parallel branches.

[0114] The DC loop model can be characterized as follows:

[0115] Among them, C div The reciprocal of the equivalent capacitance of the intermediate circuit;

[0116] R 21 R 22_ div: The equivalent reciprocal of the constant discharge resistance of the intermediate circuit;

[0117] L1dc_div: The reciprocal of the intermediate loop filter inductor L1;

[0118] C 31_ div: The reciprocal of the intermediate circuit filter capacitor C31;

[0119] R 23_ div: The reciprocal of the intermediate circuit filter capacitor and resistor R23.

[0120] Table 2 is a description of the input and output parameters of the converter module. Figure 5 is a schematic diagram of the DC loop model in the embodiment of this application. According to the topology, we can conclude that:

[0121] Where Rf is the equivalent resistance of inductor L1, and it is connected in series with L1.

[0122] The transfer function is obtained through the Laplace transform:

[0123] Discretization using the Euler method yields:

[0124] A discretized model of the DC circuit can be obtained.

[0125] Among them, U o : Output voltage of the intermediate DC circuit;

[0126] i o Total input current of the intermediate circuit;

[0127] i1: The current flowing through inductor L1;

[0128] U1: Filter capacitor C 31 Terminal voltage;

[0129] i2: Flowing through the discharge resistor network (R) 21 and R 22 The current of )

[0130] U f : Voltage drop across filter inductor L1;

[0131] R f : The equivalent resistance of the filter inductor L1;

[0132] R 21 R 22 R 23 : Resistive elements in the intermediate DC circuit;

[0133] C 31 : Filter capacitor;

[0134] L1: Filter inductor;

[0135] C: Main filter capacitor of the intermediate DC circuit;

[0136] Ts: Step size of the FPGA computing model;

[0137] s: The complex frequency variable in the Laplace transform;

[0138] z: The variable after Euler discretization;

[0139] 1 / s: The integration operator, which represents the integration operation over time in a continuous system. After discretization, it is converted into the form Ts / (z-1), which is suitable for real-time computing on FPGA.

[0140] Table 2

[0141] Preferably, in the main transformer and converter of this application, R1 = 0.01; L1 = 0.00001; R m =1.08e6; L m =2866; R_filt=50000; tau=0.003; I s =1e-7.

[0142] The DC loop model calculates the electrical characteristics of the DC bus in the rail transit traction system and simulates the dynamic response of the intermediate loop under different load conditions, improving the simulation accuracy and reliability of the traction power supply system. The model considers the electrical parameters of the filter capacitor, filter inductor, current-limiting resistor, and parallel branches, characterizing the charging and discharging characteristics, filtering effect, and dynamic impedance changes of the intermediate DC loop.

[0143] For example, when a train transitions from acceleration to constant speed, the voltage and current fluctuations in the DC circuit need to be smoothly transitioned. The model calculates the charging rate of the capacitor, the current buffering effect of the inductor, and the influence of the resistor on the current change during this process.

[0144] Furthermore, the model can also be used to evaluate the filtering performance of the DC bus at different harmonic frequencies, such as when the converter is modulated at high frequencies, the filter capacitor C 31 The combination with inductor L1 can reduce the impact of high-frequency ripple on the traction system and improve the stability of traction power supply.

[0145] The model combines Laplace transform and discretization methods, enabling it to be solved in real time at a high computational speed on the FPGA simulation platform. This improves the adaptability of rail transit systems to different electrical conditions and provides accurate simulation support for converter control strategy optimization, harmonic suppression, and energy management.

[0146] In an optional embodiment, the inverter model is used to characterize the power conversion state of the inverter under the action of a PWM control signal by simulating a three-phase bridge topology consisting of IGBT semiconductor switches and their anti-parallel diodes.

[0147] For example, as shown in Figure 6, g1 to g6 are the gate-level control signals of the IGBT, which are usually controlled by a three-phase 6-channel PWM wave. The output three-phase voltage is determined by judging the direction of the three-phase current supplied by the load.

[0148] The inverter model simulates the dynamic characteristics of the AC-DC conversion stage in a rail transit traction system, achieving high-fidelity simulation of three-phase voltage and current waveforms, thus ensuring the stable operation of the traction motor. The model employs a three-phase bridge topology, composed of six IGBT power switching devices, and uses PWM waveforms to control the amplitude and phase of the motor input voltage, ensuring that the inverter can dynamically adjust its output according to actual load requirements.

[0149] For example, when a train accelerates, the inverter needs to provide a higher amplitude sinusoidal voltage to increase the power output of the traction motor. When the train is running at a constant speed or coasting, the PWM control strategy can reduce the output voltage to decrease power loss and improve system efficiency. Furthermore, this model can also be used to analyze the harmonic characteristics of the traction system and optimize the PWM control strategy to reduce the interference of higher harmonics on the rail transit power supply system, thereby improving the stability of the power grid and the smoothness of traction motor operation.

[0150] In an optional embodiment, the asynchronous motor model is used to characterize the dynamic electrical and mechanical states of the asynchronous motor in a two-phase stationary coordinate system and a two-phase rotating coordinate system by establishing voltage equations, flux linkage equations, current equations and torque equations.

[0151] After three-phase stationary / two-phase stationary coordinate transformation and two-phase rotating / two-phase stationary coordinate transformation, the mathematical model of the asynchronous motor in the two-phase stationary coordinate system can be obtained. Table 3 is a table of input and output parameters of the inverter and asynchronous motor module. Figure 7 is a schematic diagram of the inverter model and asynchronous motor model in the embodiment of this application.

[0152] Voltage equation:

[0153] Among them, u sα u sβ u rα u rβ The voltage of the asynchronous motor, where u sα and u sβ It is the stator voltage, u rα and u rβ It is the rotor voltage;

[0154] i sα i sβ i rα ir β : Current components of the stator and rotor, where i sα and i sβ These are the α and β components of the stator current, i rα and i rβ These are the α and β components of the rotor current;

[0155] ω, L m L r ω is the angular velocity of the motor, L m It is the magnetizing inductance of the motor, L r It is the rotor inductance.

[0156] Magnetic flux linkage equation:

[0157] Where, ψ sα , ψ sβ , ψ rα , ψ rβ The magnetic flux component of the motor, where ψ sα and ψ sβ It is the stator flux linkage, ψ rα and ψ rβ It is rotor flux linkage;

[0158] L s : Stator inductance of the motor.

[0159] Current equation:

[0160] Torque equation:

[0161] Among them, T e : Motor torque, n p : Number of pole pairs of the motor.

[0162] Table 3

[0163] Preferably, in the inverter and asynchronous motor model of this application, pole_pair = 2; T s =1e-7.

[0164] The asynchronous motor model simulates the dynamic operating characteristics of the motor in the rail transit traction system by establishing complete voltage equations, flux linkage equations, current equations, and torque equations, thereby improving the realism and calculation accuracy of the simulation system in terms of motor response characteristics.

[0165] The aforementioned model, based on the transformation between a two-phase stationary coordinate system and a two-phase rotating coordinate system, can effectively analyze the electromagnetic characteristics of asynchronous motors under different operating modes, such as changes in current, voltage, and torque during starting, acceleration, constant speed operation, and braking. Especially in the traction control system of high-speed trains, the torque characteristics of the asynchronous motor directly affect the train's acceleration performance and energy efficiency ratio. This model can calculate the magnetic flux coupling relationship between the motor rotor and stator, and, combined with inverter control signals (such as PWM modulation pulses), simulate the motor's response under different load conditions in real time.

[0166] For example, during train braking, the model can accurately simulate the electromagnetic braking characteristics of an asynchronous motor entering regenerative braking mode and predict the efficiency of train energy feedback to the power grid. Furthermore, combined with an FPGA simulation platform, the model can calculate key parameters such as motor speed, current waveform, and output torque in real time, providing strong data support for the optimized design of rail transit traction systems, control algorithm debugging, and energy efficiency assessment, thereby improving the stability and energy-saving effect of the traction system.

[0167] Based on the above embodiments, using this device to simulate high-frequency harmonics on the grid side of multi-vehicle grid connection can reduce dependence on physical resources. By changing the model simulation parameters, variations in operating conditions and vehicle models can be achieved, allowing for convenient simulation of various operating conditions and configurations. The same control device can be repeatedly tested under different conditions to evaluate its performance and reliability, predict its behavior under different conditions, and provide valuable reference for design and optimization. Compared to real-vehicle testing, this device has a smaller footprint, higher flexibility, and is easier to operate. It uses mains power, is energy-efficient, and consumes only 5.5kW, reducing the risk of physical damage. Compared to fully digital simulation testing, this device offers real-time simulation, online parameter adjustment, and faster simulation speed. The controller uses a real vehicle controller, resulting in high simulation accuracy. Using this device can significantly save time, labor, and economic costs.

[0168] To simulate multi-vehicle grid connection and study the performance of harmonic suppression algorithms, this application provides an embodiment of a simulation method for simulating grid-side harmonics in multi-vehicle grid connection of rail vehicles, as shown in Figure 8. The method is applied to a simulator and includes:

[0169] Step S101: Obtain the simulation model of the rail transit power supply system;

[0170] Step S102: Generate corresponding simulation input signals based on the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals.

[0171] Step S103: Obtain the simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0172] As can be seen from the above description, the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid provided in this application embodiment can realize the simulation of multiple vehicles connected to the grid, and be used to study the performance of harmonic suppression algorithms.

[0173] In order to simulate multi-vehicle grid connection and study the performance of harmonic suppression algorithms, this application provides an embodiment of a simulation device for simulating grid-side harmonics of multi-vehicle grid connection of rail vehicles, which includes all or part of the simulation method for simulating grid-side harmonics of multi-vehicle grid connection. Referring to Figure 9, the simulation device for simulating grid-side harmonics of multi-vehicle grid connection of rail vehicles specifically includes the following components:

[0174] The model acquisition module 1101 is used to: acquire the simulation model of the rail transit power supply system. The simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model.

[0175] The simulation operation module 1102 is used to: generate corresponding simulation input signals according to the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals.

[0176] The status feedback module 1103 is used to: acquire simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0177] As can be seen from the above description, the simulation device for simulating harmonics on the grid side of multiple rail vehicles connected to the grid provided in this application embodiment can realize the simulation of multiple vehicles connected to the grid, and be used to study the performance of harmonic suppression algorithms.

[0178] From a hardware perspective, in order to simulate multi-vehicle grid connection and study the performance of harmonic suppression algorithms, this application provides an embodiment of an electronic device for implementing all or part of the simulation method for simulating grid-side harmonics in multi-vehicle grid connection of rail vehicles. The electronic device specifically includes the following:

[0179] The system comprises a processor, memory, a communication interface, and a bus. The processor, memory, and communication interface communicate with each other via the bus. The communication interface is used to transmit information between the simulation device for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, the core business system, user terminals, and related databases. The logic controller can be a desktop computer, tablet computer, or mobile terminal, but this embodiment is not limited to these. In this embodiment, the logic controller can be implemented with reference to the embodiments of the simulation method and the simulation device for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, the contents of which are incorporated herein by reference, and repeated details will not be elaborated further.

[0180] It is understood that user terminals can include smartphones, tablet computers, network set-top boxes, portable computers, desktop computers, personal digital assistants (PDAs), in-vehicle devices, and smart wearable devices. Among these, smart wearable devices can include smart glasses, smartwatches, and smart bracelets.

[0181] In practical applications, the simulation method for harmonic simulation on the grid side of multi-vehicle grid connection in rail vehicles can be partially executed on the electronic equipment side as described above, or all operations can be completed in the client device. The choice can be made based on the processing power of the client device and the limitations of the user's usage scenario. This application does not impose any limitations on this. If all operations are completed in the client device, the client device may also include a processor.

[0182] The aforementioned client devices may have a communication module (i.e., a communication unit) that can communicate with a remote server to achieve data transmission. The server may include a server on the task scheduling center side; in other implementation scenarios, it may also include a server on an intermediate platform, such as a server on a third-party server platform that has a communication link with the task scheduling center server. The server may be a single computer device, a server cluster consisting of multiple servers, or a distributed server structure.

[0183] Embodiments of this application also provide a computer-readable storage medium capable of implementing all steps in the simulation method for multi-vehicle grid-connected harmonic simulation of rail vehicles with server or client execution subjects as described in the above embodiments. The computer-readable storage medium stores a computer program that, when executed by a processor, implements all steps in the simulation method for multi-vehicle grid-connected harmonic simulation of rail vehicles with server or client execution subjects as described in the above embodiments. For example, when the processor executes the computer program, it implements the following steps:

[0184] Step S101: Obtain the simulation model of the rail transit power supply system. The simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model.

[0185] Step S102: Generate corresponding simulation input signals based on the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals.

[0186] Step S103: Obtain the simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0187] As can be seen from the above description, the computer-readable storage medium provided in the embodiments of this application realizes the simulation of multi-vehicle grid connection, and is used to study the performance of harmonic suppression algorithm.

[0188] Embodiments of this application also provide a computer program product capable of implementing all steps in the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid, where the execution subject is a server or client, as described in the above embodiments. When executed by a processor, this computer program / instruction implements the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid. For example, the computer program / instruction implements the following steps:

[0189] Step S101: Obtain the simulation model of the rail transit power supply system. The simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model.

[0190] Step S102: Generate corresponding simulation input signals based on the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals.

[0191] Step S103: Obtain the simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

[0192] As can be seen from the above description, the computer program product provided in the embodiments of this application simulates multi-vehicle grid connection and is used to study the performance of harmonic suppression algorithms.

[0193] Those skilled in the art will understand that embodiments of this application can be provided as methods, apparatus, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0194] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (devices), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in one or more blocks of the flowchart illustrations and / or one or more blocks of the block diagrams.

[0195] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means that implement the functions specified in one or more flowcharts and / or one or more block diagrams.

[0196] These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process, such that the instructions, which execute on the computer or other programmable apparatus, provide steps for implementing the functions specified in one or more flowcharts and / or one or more block diagrams.

[0197] This application uses specific embodiments to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A simulation system for track vehicle multi-car grid-connected grid-side harmonic simulation, characterized in that, This includes the host computer, simulator, and signal distribution system; The host computer is used to send the simulation model of the rail transit power supply system to the simulator and receive the real-time operating status returned by the simulator. The simulator is used to receive and run the simulation model and generate corresponding simulation input signals, including voltage and current analog signals, digital feedback signals and speed encoder signals. The signal distribution system is used to send the simulation input signal to multiple physical control units of the vehicle based on preset rules, and to send the simulation output signal returned by the multiple physical control units to the simulator, so that the simulator returns the real-time operating status to the host computer according to the simulation output signal. The simulation output signal includes control pulse signal and digital control signal.

2. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog according to claim 1, characterized in that, The simulation model includes one or any combination of the following models: Including the network compression calculation model; Four-quadrant pulse rectifier model; Traction transformer model; Pre-charge model; Four-quadrant rectifier model; DC loop model; Inverter model; Asynchronous motor model.

3. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog according to claim 2, characterized in that, The signal distribution system includes a signal distribution unit and a signal conditioning unit; The signal distribution unit is used to distribute the simulation input signal based on a preset rule, and send the simulation output signal returned by the plurality of physical control units to the simulator; The signal conditioning unit is used to send the distributed simulation input signal to multiple physical control units; as well as The simulation input signal is converted to an input format compatible with the physical control unit, and the simulation output signal is converted to an input format compatible with the simulator.

4. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog according to claim 2, characterized in that, The grid voltage calculation model is used to characterize the voltage and current state of the transformer under no-load, short-circuit, and load operating conditions by using the electrical parameter relationship between the primary and secondary sides of the transformer.

5. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The four-quadrant pulse rectifier model is used to characterize the DC circuit current state through the electrical relationship between the rectifier output current and the total load current.

6. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The traction transformer model is used to characterize the level transformation state of the transformer in the rail transit traction system by establishing the parameter relationship between the primary and secondary sides of the transformer.

7. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The pre-charge model is used to characterize the pre-charge state of the traction converter during the initial power-on process by simulating the circuit structure of the pre-charge contactor, main contactor, filter capacitor, filter resistor, current-limiting resistor and LC filter.

8. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The four-quadrant rectifier model is used to characterize the operating state of the single-phase two-level four-quadrant rectifier during the AC-to-DC power conversion process by simulating the circuit structure of a single-phase two-level four-quadrant rectifier composed of IGBT half-bridge modules.

9. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The DC loop model is used to characterize the electrical state of the DC bus in the traction system of a rail vehicle by establishing the electrical parameter relationships of the filter capacitor, filter inductor, current-limiting resistor, and parallel branches.

10. The simulation system for rail vehicle multi-car grid-connected grid-side harmonic analog of claim 2, wherein, The inverter model is used to characterize the power conversion state of the inverter under the action of PWM control signal by simulating a three-phase bridge topology consisting of IGBT semiconductor switches and their anti-parallel diodes.

11. The simulation system for multi-train grid-connected grid-side harmonic analog of rail vehicles according to claim 2, characterized in that, The asynchronous motor model is used to characterize the dynamic electrical and mechanical states of the asynchronous motor in a two-phase stationary coordinate system and a two-phase rotating coordinate system by establishing voltage equations, flux linkage equations, current equations and torque equations.

12. A simulation method of a rail vehicle multi-car grid-connected grid-side harmonic simulation, characterized in that, The simulator applied to the simulator of claim 1 includes: Obtain a simulation model of the rail transit power supply system; The simulation input signal is generated according to the simulation model, and the simulation input signal is sent to multiple physical control units according to preset rules through the signal distribution system. The simulation input signal includes voltage and current analog signals, digital feedback signals and speed encoder signals. The simulation output signals returned by multiple physical control units are acquired, and the real-time operating status is returned to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

13. A simulation device for rail vehicle multi-car grid-connected grid-side harmonic simulation, characterized in that, The simulator applied to the simulator of claim 1 includes: The model acquisition module is used to: acquire a simulation model of the rail transit power supply system, wherein the simulation model includes at least one of the following: grid voltage calculation model, four-quadrant pulse rectifier model, traction transformer model, pre-charge model, four-quadrant rectifier model, DC circuit model, inverter model, and asynchronous motor model; The simulation operation module is used to: generate corresponding simulation input signals according to the simulation model, and send the simulation input signals to multiple physical control units according to preset rules through the signal distribution system. The simulation input signals include voltage and current analog signals, digital feedback signals and speed encoder signals. The status feedback module is used to: acquire simulation output signals returned by multiple physical control units, and return the real-time operating status to the host computer based on the simulation output signals. The simulation output signals include control pulse signals and digital control signals.

14. An electronic device comprising a memory, a processor, and a computer program stored on the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid as described in claim 12.

15. A computer readable storage medium having stored thereon a computer program, characterized in that, When the computer program is executed by the processor, it implements the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid as described in claim 12.

16. A computer program product comprising computer programs / instructions, characterized in that, When the computer program / instruction is executed by the processor, it implements the steps of the simulation method for simulating harmonics on the grid side of multiple rail vehicles connected to the grid as described in claim 12.

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