Electric vehicle charging pile modeling method for dynamic simulation platform of power distribution network

Abstract

The invention discloses an electric vehicle charging pile modeling method for a power distribution network dynamic simulation platform, and relates to the technical field of data processing, and the method comprises the steps: determining main components of an electric vehicle charging pile according to a functional structure of the electric vehicle charging pile; establishing a voltage response module, and constructing a voltage response mathematical model; constructing a frequency response module, setting frequency trip response curve points, and establishing a frequency response mathematical model; constructing a state of charge management module, and realizing SOC upper and lower limit management logic; and performing power grid safety assessment, and integrating the power grid safety assessment into the electric vehicle charging pile model. According to the invention, the service life and safety management of the battery of the electric vehicle are guaranteed, and the model has good universality and expandability.

Description

Technical Field

[0001] The invention relates to the technical field of data processing, and in particular to a modeling method for an electric vehicle charging pile used in a dynamic simulation platform of a distribution network. Background Art

[0002] As the number of electric vehicles continues to grow, electric vehicle charging piles are connected to the distribution network in large numbers. The impact of electric vehicle charging and discharging on the power system is becoming increasingly significant. The voltage and frequency response of electric vehicle charging piles in the power grid has become a focus issue, which can effectively support the safe and stable operation of the distribution network with large-scale electric vehicle access. The modeling technology of electric vehicle charging piles is crucial to understand their dynamic behavior, evaluate their impact on the voltage and frequency response of the power grid, and achieve safe and stable operation of the distribution network. For electric vehicle charging piles, the response characteristics when abnormal fluctuations occur when they are connected to the power grid are an important research direction.

[0003] At present, in the simulation and calculation of distribution networks, electric vehicles are often regarded as loads, and their transient characteristics of participating in the frequency and voltage response of the power grid cannot be simulated. However, this rough modeling method cannot support the safety and stability analysis and system dynamic evaluation of the distribution network connected to large-scale electric vehicles. Therefore, it is urgent to carry out refined modeling research considering the participation of electric vehicle charging piles in the voltage and frequency response of the power grid.

[0004] In the research on modeling the voltage and frequency response characteristics of electric vehicle charging piles in the power grid, an important task is to develop a high-precision control model for electric vehicle charging piles to simulate the response and dynamic behavior of the charging piles when the voltage and frequency of the power grid to which the charging piles are connected fluctuate abnormally. This includes the monitoring of the voltage and frequency of the power grid by the controller, the response strategy to voltage and frequency anomalies, and the regulation of the input and output power of the electric vehicle.

[0005] In addition, the interaction and impact between EV charging piles and other components of the power system also need to be considered. For example, the coordinated operation of EV charging piles with traditional generators, load equipment, and power electronic devices may cause voltage instability, frequency deviation, and harmonic disturbances. Therefore, the interactive effects of EV charging piles and power systems need to be comprehensively considered in modeling research to accurately evaluate their impact on the stability of power system operation and power quality.

[0006] In recent years, the industry and academia have gradually increased the research on modeling of electric vehicle charging piles. However, these studies often ignore the differences in production technology between different manufacturers. Due to the existence of practical problems such as the need to keep the technical details of the manufacturer's equipment confidential, the modeling work faces many difficulties, especially when promoting the simulation of distribution networks. However, as the structure of the distribution network becomes increasingly complex, the large-scale access of electric vehicles has brought new power quality problems. Therefore, it is urgent to establish a set of standard, effective, concise and open general models to meet the needs of large-scale distribution network simulation analysis. Such a general model should be able to cover the dynamic differences between equipment from different manufacturers and overcome the modeling difficulties caused by technical confidentiality. It should be a simplified model that can meet the simulation needs and protect the commercial interests of the manufacturer's equipment. The establishment of this general model will greatly facilitate the simulation of distribution networks.

[0007] The existing distribution network electric vehicle charging pile modeling method uses inconsistent platforms and types of electric vehicle charging piles, and has poor versatility. It is difficult to be compatible when conducting large-scale distribution network dynamic simulation, and cannot take into account the speed and accuracy required for large-scale dynamic simulation. At the same time, it lacks the dynamic characteristics simulation of the voltage and frequency response of the distribution network involving electric vehicles. Summary of the invention

[0008] In view of the problems existing in the existing modeling research of electric vehicle charging piles, the present invention is proposed.

[0009] Therefore, the problem to be solved by the present invention is to consider the voltage and frequency dynamic response of the distribution network in which the electric vehicle charging and discharging participate after the electric vehicle charging pile is connected to the distribution network.

[0010] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0011] In the first aspect, an embodiment of the present invention provides an electric vehicle charging pile modeling method for a distribution network dynamic simulation platform, which includes determining the main components of the electric vehicle charging pile model according to the functional structure of the electric vehicle charging pile; establishing a voltage response module, and constructing a voltage response mathematical model; constructing a frequency response module, setting frequency tripping response curve points, and establishing a frequency response mathematical model; constructing a charge state management module to implement SOC upper and lower limit management logic; performing a power grid security assessment and integrating it into the electric vehicle charging pile model.

[0012] As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform described in the present invention, the main components of the electric vehicle charging pile model include voltage response part modeling, frequency response part modeling, charge state management part modeling and safety assessment.

[0013] As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform described in the present invention, the construction of the voltage response mathematical model includes calculating the low voltage response coefficient and calculating the high voltage response coefficient; the calculation of the low voltage response coefficient and the high voltage response coefficient is as follows:

[0014] F vl =K vt01 z i VL1 (VV to )+z u VL1

[0015]

[0016] Among them, K vt01 The voltage slope of the low voltage response part; It is the pointer of voltage in low voltage area; The voltage is not in the low voltage area. t0 is the voltage trip response curve point 0; V is the voltage amplitude connected to the AC power grid; V t1 is the voltage trip response curve point 1;

[0017] F vh =K vt23 z i VL2 (VV t2 )+z l VL2

[0018]

[0019] Among them, K vt23 The voltage slope of the high voltage response part; The pointer indicates that the voltage is in the high voltage area; The voltage is not in the high voltage area. t2 is the voltage trip response curve point 2; V t3 is the voltage trip response curve point 3. As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform of the present invention, wherein: the frequency response mathematical model includes calculating the low frequency response coefficient and the high frequency response coefficient, and the formula is as follows:

[0020] F fl =K ft01 z i FL1 (FF to )+z u FL1

[0021]

[0022] Among them, K ft01 is the frequency slope of the low frequency response part; It is the pointer of frequency in low frequency area; The frequency is not in the low frequency area. t0 is the frequency trip response curve point 0; F t1 is the frequency trip response curve point 1; F is the frequency value of the AC power grid;

[0023] F fh =K ft23 z i FL2 (FF t2 )+z l FL2

[0024]

[0025] Among them, K ft23 is the frequency slope of the high frequency response part; It is the pointer of frequency in high frequency area; The frequency is not in the high frequency area. t3 This is point 3 of the V frequency trip response curve.

[0026] As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform described in the present invention, wherein: the active current command value I of the electric vehicle charging pile pcmd and reactive current command value I qcmd The generation process is as follows:

[0027]

[0028] As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform described in the present invention, the SOC upper and lower limit management logic includes: when the electric vehicle state of charge reaches the upper limit SOC max When the electric vehicle stops charging and enters the discharge state, I pmin Set to 0 to limit the electric vehicle to the discharge state; when the electric vehicle's state of charge reaches the lower limit SOC min When the electric vehicle stops discharging, it can only enter the charging state. pmax Set to 0 to limit the electric vehicle to the charging state, where I pmin Active power command value I pcmd The lower limit of I pmax I is the active power command value pcmd upper limit.

[0029] As a preferred solution of the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform of the present invention, wherein: the charge state management part modeling includes: when the electric vehicle is in the charging state:

[0030] SOC=SOC ini -P elect ×EtaC(P elect <0)

[0031] When the electric vehicle is in a discharging state:

[0032] SOC=SOC ini -P elect ×EtaD(P elect >0)

[0033] Among them, EtaC is the charging efficiency, EtaD is the discharging efficiency, SOC ini It is the initial state of charge of the electric vehicle; the state of charge SOC of the electric vehicle should comply with the following constraints:

[0034] SOC min ≤SOC≤SOC max

[0035] The constraints of the electric vehicle's state of charge on the charging and discharging power are as follows:

[0036] SOC ≥ SOC max I pmin =0

[0037] SOC≤SOC min I pmax =0.

[0038] In the second aspect, an embodiment of the present invention provides an electric vehicle charging pile modeling system for a distribution network dynamic simulation platform, which includes: a charging pile structure analysis module, which is used to determine the main components of the electric vehicle charging pile according to the functional structure of the electric vehicle charging pile; a voltage response module function, which is used to construct a voltage response mathematical model; a frequency response module, which is used to set the frequency trip response curve points and establish a frequency response mathematical model; a charge state management module function, which is used to implement SOC upper and lower limit management logic; a power grid security assessment module, which is used to perform power grid security assessment and integrate it into the electric vehicle charging pile model.

[0039] In a third aspect, an embodiment of the present invention provides a computer device, comprising a memory and a processor, wherein the memory stores a computer program, wherein: when the computer program instructions are executed by the processor, the steps of the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform as described in the first aspect of the present invention are implemented.

[0040] In a fourth aspect, an embodiment of the present invention provides a computer-readable storage medium having a computer program stored thereon, wherein: when the computer program instructions are executed by a processor, the steps of the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform as described in the first aspect of the present invention are implemented.

[0041] The beneficial effects of the present invention are as follows: the present invention decomposes the functions of electric vehicle charging piles and expresses its mechanism with block transfer functions, which includes voltage management and frequency management after the electric vehicle charging piles are connected to the distribution network, and can reflect the dynamic process after entering the distribution network. The model also includes charge state management of electric vehicles during the charging and discharging process, ensuring the battery life and safety management of electric vehicles. The model has good versatility and scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0043] Figure 1 Schematic diagram of the charging pile model for electric vehicles.

[0044] Figure 2 This is the structural diagram of the electric vehicle charging pile model.

[0045] Figure 3 This is a schematic diagram of the voltage response of an electric vehicle charging pile.

[0046] Figure 4 This is a partial schematic diagram of the frequency response of an electric vehicle charging station.

[0047] Figure 5 This is a schematic diagram of the charge state management part of an electric vehicle. DETAILED DESCRIPTION

[0048] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings.

[0049] In the following description, many specific details are set forth to facilitate a full understanding of the present invention, but the present invention may also be implemented in other ways different from those described herein, and those skilled in the art may make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0050] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The term "in one embodiment" that appears in different places in this specification does not necessarily refer to the same embodiment, nor does it refer to a separate or selective embodiment that is mutually exclusive with other embodiments.

[0051] Example 1

[0052] Reference Figure 1 to Figure 5 , which is the first embodiment of the present invention, and provides an electric vehicle charging pile modeling method for a distribution network dynamic simulation platform, comprising:

[0053] S1: Determine the main components of the electric vehicle charging pile model based on the functional structure of the electric vehicle charging pile.

[0054] Specifically, Figure 2 This is the structure diagram of the electric vehicle charging pile model, for reference Figure 1 and Figure 2 The description of each parameter is given in Table 1. The electric vehicle charging pile model includes voltage response modeling, frequency response modeling, charge state management modeling and other parts.

[0055] The input of the electric vehicle charging pile model is the active power value, the reactive power value, the frequency reference value, the voltage connected to the AC power grid, the frequency connected to the AC power grid, etc.; the output of the electric vehicle charging pile model is the active current connected to the AC power grid, the reactive current connected to the AC power grid, etc.

[0056] The electric vehicle charging pile model simulates the power interaction between the electric vehicle charging pile and the power grid, the change in charging rate, the protection of electric vehicle charging and discharging batteries, and the participation of electric vehicles in the voltage and frequency regulation of the power grid.

[0057] Table 1 Electric vehicle charging pile model parameter comparison table

[0058] character describe <![CDATA[P elec ]]> Electric vehicles exchange power with the grid EtaC Charging rate EtaD Discharge rate SOC State of Charge <![CDATA[SOC int ]]> Initial state of charge of electric vehicles <![CDATA[SOC max ]]> Maximum state of charge of electric vehicles <![CDATA[SOC min ]]> Minimum state of charge for electric vehicles Qmax Maximum reactive power command Q Minimum reactive power command <![CDATA[V0]]> Dead zone lower limit of voltage droop response <![CDATA[V1]]> Deadband upper limit of voltage droop response dqV Voltage droop response characteristics <![CDATA[V t0 ]]> Voltage trip response curve point 0 <![CDATA[V t1 ]]> Voltage trip response curve point 1 <![CDATA[V t2 ]]> Voltage trip response curve point 2 <![CDATA[V t3 ]]> Voltage trip response curve point 3 <![CDATA[F t0 ]]> Frequency trip response curve point 0 <![CDATA[F t1 ]]> Frequency trip response curve point 1 <![CDATA[F t2 ]]> Frequency trip response curve point 2 <![CDATA[F t3 ]]> V frequency trip response curve point 3 <![CDATA[T g (I p )]]> Charging pile active current hysteresis time constant <![CDATA[T g (I q )]]> Charging pile reactive current hysteresis time constant <![CDATA[V t ]]> AC grid voltage <![CDATA[P ref ]]> Initial active power <![CDATA[F ref ]]> AC grid frequency <![CDATA[Q ref ]]> Initial reactive power <![CDATA[I pcmd ]]> Active current command value <![CDATA[I qcmd ]]> Reactive current command value

[0059] The present invention realizes the construction of a universal model of electric vehicle charging piles by analyzing the structure and function of electric vehicle charging piles. The model can be adapted to electric vehicle charging piles from different manufacturers and has good scalability.

[0060] S2: Establish a voltage response module and construct a voltage response mathematical model.

[0061] The present invention models the dynamic management of distribution network voltage after an electric vehicle charging pile is connected to the distribution network.

[0062] Figure 3 This is a schematic diagram of the voltage response of an electric vehicle charging pile. The input in the red area is the voltage connected to the AC power grid.vl is the low voltage response factor, F vh is the high voltage response coefficient, and the calculations of the low voltage response coefficient and the high voltage response coefficient are as follows:

[0063] F vl =K vt01 z i VL1 (VV to )+z u VL1

[0064]

[0065] Among them, K vt01 The voltage slope of the low voltage response part; It is the pointer of voltage in low voltage area; The voltage is not in the low voltage area. t0 is the voltage trip response curve point 0; V is the voltage amplitude connected to the AC power grid; V t1 is the voltage trip response curve point 1;

[0066] F vh =K vt23 z i VL2 (VV t2 )+z l VL2

[0067]

[0068] Among them, K vt23 The voltage slope of the high voltage response part; The pointer indicates that the voltage is in the high voltage area; The voltage is not in the high voltage area. t2 is the voltage trip response curve point 2; V t3 It is point 3 of the voltage trip response curve.

[0069] The low voltage response coefficient and high voltage response coefficient act on the active current command value I of the electric vehicle charging pile pcmd and reactive current command value I qcmd Generate to reflect the voltage response dynamics of electric vehicle charging piles participating in the access to the power grid.

[0070] S3: Construct a frequency response module, set frequency trip response curve points, and establish a frequency response mathematical model.

[0071] Figure 4 This is a partial schematic diagram of the frequency response of an electric vehicle charging station. flis the low frequency response coefficient, F fh is the high frequency response coefficient, where the low frequency response coefficient and the high frequency response coefficient are calculated as follows:

[0072] F fl =K ft01 z i FL1 (FF to )+z u FL1

[0073]

[0074] Among them, K ft01 is the frequency slope of the low frequency response part; It is the pointer of frequency in low frequency area; The frequency is not in the low frequency area. t0 is the frequency trip response curve point 0; F t1 is the frequency tripping response curve point 1; F is the frequency value of the connected AC power grid.

[0075] F fh =K ft23 z i FL2 (FF t2 )+z l FL2

[0076]

[0077] Among them, K ft23 is the frequency slope of the high frequency response part; It is the pointer of frequency in high frequency area; The frequency is not in the high frequency area. t3 This is point 3 of the V frequency trip response curve.

[0078] The low frequency response coefficient and the high frequency response coefficient act on the active current command value I of the electric vehicle charging pile pcmd and reactive current command value I qcmd Generate to reflect the frequency response dynamics of electric vehicle charging piles participating in the access to the power grid.

[0079]

[0080]

[0081]

[0082] The present invention models the dynamic management of the frequency of the distribution network after the electric vehicle charging pile is connected to the distribution network.

[0083] S4: Build a state of charge management module to implement SOC upper and lower limit management logic.

[0084] Figure 5 This is a schematic diagram of the state of charge management of an electric vehicle. The input in the red area is the interaction power between the electric vehicle and the power grid. EtaC is the charging efficiency, EtaD is the discharging efficiency, and SOC ini It is the initial state of charge of the electric vehicle.

[0085] SOC min It is the lower limit of the state of charge of the electric vehicle. When the state of charge of the electric vehicle reaches the lower limit SOC min , the electric vehicle should stop discharging and can only enter the charging state; SOC max It is the upper limit of the state of charge of the electric vehicle. When the state of charge of the electric vehicle reaches the upper limit SOC max , the electric car should stop charging and can only enter the discharge state.

[0086] Among them, the mathematical modeling of electric vehicle charge state management includes:

[0087] When the electric vehicle is charging:

[0088] SOC=SOC ini -P elect ×EtaC(P elect <0)

[0089] When the electric vehicle is in a discharging state:

[0090] SOC=SOC ini -P elect ×EtaD(P elect >0)

[0091] The state of charge (SOC) of electric vehicles should comply with the following constraints:

[0092] SOC min ≤SOC≤SOC max

[0093] Constraints of electric vehicle charge state on charging and discharging power (charging and discharging current):

[0094] SOC ≥ SOC max I pmin =0

[0095] SOC≤SOC min I pmax =0

[0096] When the state of charge of the electric vehicle reaches the upper limit (SOC max), the electric car should stop charging to avoid damaging the battery. At this time, it can only enter the discharge state. pmin Set to 0 to limit the electric vehicle to the discharge state; when the electric vehicle's state of charge reaches the lower limit (SOC min ), the electric vehicle should stop discharging and can only enter the charging state. pmax Set to 0 to limit the electric vehicle to the charging state; pmin I is the active power command value pcmd The lower limit of I pmax Active power command value I pcmd upper limit.

[0097] The present invention models the charge state management during the charging and discharging process of an electric vehicle, and considers the charging and discharging rate of the electric vehicle in the modeling process.

[0098] S5: Conduct grid security assessment and integrate it into the electric vehicle charging station model.

[0099] Safety indicators include: voltage deviation rate ΔV, line load rate Lload, transformer load rate Tload and harmonic distortion rate THD.

[0100] Furthermore, a safety assessment mathematical model is established, including:

[0101] The voltage deviation rate is calculated as:

[0102]

[0103] Where V is the actual voltage, V n is the rated voltage.

[0104] The line load factor is calculated as:

[0105]

[0106] Among them, I is the actual current and Irated is the rated current of the line.

[0107] The transformer load factor is calculated as:

[0108]

[0109] Where, S is the actual apparent power, S rated is the rated capacity of the transformer.

[0110] The harmonic distortion is calculated as:

[0111]

[0112] Among them, Ih is the effective value of the hth harmonic current, and I1 is the effective value of the fundamental current.

[0113] Set safety thresholds, for example: voltage deviation rate threshold is ΔVmax = ±7%; line load rate threshold is Lloadmax = 80%; transformer load rate threshold is Tloadmax = 90%; harmonic distortion rate threshold is THDmax = 5%; safety assessment logic is:

[0114] If (|ΔV|<=ΔVmax)AND(Lload<=Lloadmax)AND(Tload<=Tloadmax)AND(THD<=THDmax), the system operates safely. If the above rules are not met, a safety warning is triggered, the corresponding control strategy is called, and the safety assessment results are fed back to the charging control strategy: when approaching or exceeding the safety threshold, the charging power is adjusted or charging is suspended to achieve dynamic charging power regulation and ensure safe and stable operation of the distribution network.

[0115] Furthermore, this embodiment also provides an electric vehicle charging pile modeling system for a distribution network dynamic simulation platform, comprising:

[0116] The charging pile structure analysis module is used to determine the main components of the electric vehicle charging pile according to the functional structure of the electric vehicle charging pile; the voltage response module function is used to construct a voltage response mathematical model; the frequency response module is used to set the frequency trip response curve points and establish a frequency response mathematical model; the state of charge management module function is used to implement the SOC upper and lower limit management logic; the power grid security assessment module is used to conduct power grid security assessment and integrate it into the electric vehicle charging pile model.

[0117] This embodiment also provides a computer device, which is suitable for the electric vehicle charging pile modeling method of the distribution network dynamic simulation platform, including a memory and a processor; the memory is used to store computer executable instructions, and the processor is used to execute computer executable instructions to implement the electric vehicle charging pile modeling method for the distribution network dynamic simulation platform proposed in the above embodiment.

[0118] The computer device may be a terminal, and the computer device includes a processor, a memory, a communication interface, a display screen and an input device connected via a system bus. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, an operator network, NFC (near field communication) or other technologies. The display screen of the computer device may be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device may be a touch layer covering the display screen, or a key, trackball or touchpad provided on the housing of the computer device, or an external keyboard, touchpad or mouse, etc.

[0119] This embodiment also provides a storage medium on which a computer program is stored. When the program is executed by a processor, the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform as proposed in the above embodiment is implemented.

[0120] In summary, the present invention decomposes the functions of electric vehicle charging piles and expresses its mechanism with block transfer functions, which includes the voltage management and frequency management of electric vehicle charging piles after they are connected to the distribution network, and can reflect the dynamic process after they are connected to the distribution network. The model also includes the charge state management of electric vehicles during the charging and discharging process, ensuring the battery life and safety management of electric vehicles. The model has good versatility and scalability.

[0121] Example 2

[0122] Reference Figure 1 to Figure 5 , which is the second embodiment of the present invention, and this embodiment provides an electric vehicle charging pile modeling method for a distribution network dynamic simulation platform. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through simulation experiments.

[0123] Specifically, a typical urban distribution network is selected as the research object. The distribution network contains 100 10kV distribution transformers with a total capacity of 200MVA.

[0124] Three different types of electric vehicle charging piles were selected for modeling, namely fast charging pile (120kW), slow charging pile (7kW) and bidirectional V2G charging pile (50kW).

[0125] Use MATLAB / Simulink software to build a distribution network dynamic simulation platform. Prepare a typical load curve and electric vehicle charging demand data for one week (168 hours).

[0126] Detailed implementation process:

[0127] First, the functional structure of three different types of charging piles is analyzed. Through the analysis, the main components of the electric vehicle charging pile model are determined to include: power interface module, AC / DC conversion module, DC / DC conversion module, control management module, communication interface module and protection module.

[0128] In order to improve the versatility and scalability of the model, a modular structure is designed so that the model can be adapted to electric vehicle charging piles from different manufacturers.

[0129] Specifically, each functional module is designed as a replaceable submodule, and a standardized interface is defined. In this way, when it is necessary to simulate charging piles of different types or manufacturers, only the corresponding submodule needs to be replaced without modifying the entire model structure.

[0130] In this embodiment, the focus is on the modeling of the voltage response part, the frequency response part and the charge state management part, which directly affect the interaction between the charging pile and the power grid and the service life of the electric vehicle battery.

[0131] In order to verify the scalability of the model, models were established for three types of charging piles and parameter settings were made: Fast charging pile (120kW): rated input voltage: 380V AC; output voltage range: 200-750V DC; maximum charging current: 200A; efficiency: ≥95%;

[0132] Slow charging pile (7kW): Rated input voltage: 220V AC; Output voltage range: 200-450V DC; Maximum charging current: 32A; Efficiency: ≥90%

[0133] Bidirectional V2G charging station (50kW): Rated input / output voltage: 380V AC; DC output voltage range: 200-750V; Maximum charge / discharge current: 100A; Efficiency: ≥93%.

[0134] Through this modular and parameterized design, a universal electric vehicle charging pile model was successfully constructed, which can flexibly adapt to charging piles of different types and manufacturers, greatly improving the practicality and scalability of the model.

[0135] In order to focus on how the charging pile responds to the changes in grid voltage, a dynamic response model is designed, which enables the charging pile to adjust its charging power according to the changes in grid voltage, thereby participating in the voltage regulation of the grid.

[0136] Taking the fast charging pile (120kW) as an example, the following parameters are set: Normal operating voltage range: 342V-418V (±10% of the rated voltage 380V); Voltage trip response curve point: V t0 =330V,V t1 =342V,V t2 =418V,V t3 =430V;

[0137] according to Figure 3 The voltage response model shown in the figure calculates the low voltage response coefficient F vl and high voltage response factor F vh :When the grid voltage V=335V:

[0138] K vt01 =1 / (V t1 -V t0 )=1 / (342-330)=0.0833;

[0139]

[0140] When the grid voltage V=425V:

[0141] K vt23 =-1 / (V t2 -V t3 )=-1 / (418-430)=0.0833;

[0142]

[0143]

[0144] These response coefficients will be used to adjust the active current command value I of the charging pile. pcmd and reactive current command value I qcmd , thereby realizing the dynamic response of the charging pile to the changes in grid voltage.

[0145] The response mechanism of the charging pile to the change of grid frequency is also designed, which is particularly important for maintaining the stability of the grid, especially when a large amount of renewable energy is connected:

[0146] The following frequency response parameters are set for the fast charging pile (120kW):

[0147] Normal operating frequency range: 49.5Hz-50.5Hz; frequency trip response curve point: F t0 =49.0Hz,F t1 =49.5Hz,F t2 =50.5Hz,F t3 =51.0Hz;

[0148] Calculate the low frequency response coefficient F according to the provided frequency response model fl and high frequency response coefficient F fh :

[0149] When the grid frequency F=49.3Hz:

[0150] K ft01 =1 / (F t1 -F t0 )=1 / (49.5-49.0)=2

[0151]

[0152] When the grid frequency F=50.7Hz:

[0153] K ft23 =-1 / (F t2 -F t3 )=-1 / (50.5-51.0)=2;

[0154]

[0155] These response coefficients will be used to adjust the active current command value I of the charging pile. pcmd and reactive current command value I qcmd , thereby realizing the dynamic response of the charging pile to the changes in grid frequency.

[0156] Furthermore, in order to manage the state of charge of electric vehicle batteries to ensure battery safety and extend their service life, the following parameters are set for electric vehicle batteries:

[0157] Battery capacity: 60kWh, SOC initial value (SOC ini ): 50%, SOC lower limit (SOC min ): 10%, SOC upper limit (SOC max ): 90%, charging efficiency (EtaC): 0.95, discharge efficiency (EtaD): 0.92;

[0158] Assume that at t = 0, the electric vehicle starts charging, and the charging power P elec =50kW, for 1 hour, the SOC after 1 hour can be calculated:

[0159] SOC=50%-(-50kW)*0.95*(1h / 60kWh)=50%+79.17%=129.17%;

[0160] Since 129.17%>SOC max (90%), the system will automatically limit charging and I pmaxSet to 0 to maintain SOC at 90%.

[0161] Next, suppose the electric vehicle starts discharging, and the discharge power P elec =30kW, lasting for 2 hours, the SOC after 2 hours can be calculated:

[0162] SOC=90%-30kW*0.92*(2h / 60kWh)=90%-92%=-2%;

[0163] Due to -2% <SOC min (10%), the system will automatically stop discharging and I pmin Set to 0 to maintain the SOC at 10%.

[0164] This SOC management strategy effectively protects the battery from overcharging and over-discharging, thus extending the battery life.

[0165] In addition, grid security assessment is integrated into the charging pile model to ensure that the charging process does not have a negative impact on the distribution network.

[0166] Through this dynamic adjustment mechanism, the charging pile model of the present invention can not only respond to the voltage and frequency changes of the power grid, but also adjust the charging strategy in real time according to the safety status of the distribution network, thereby effectively ensuring the safe and stable operation of the distribution network while meeting the charging needs of electric vehicles.

[0167] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A modeling method for electric vehicle charging piles for a distribution network dynamic simulation platform, characterized in that: include, According to the functional structure of electric vehicle charging pile, determine the main components of the electric vehicle charging pile model; Establish a voltage response module and construct a voltage response mathematical model; Construct frequency response module, set frequency trip response curve points, and establish frequency response mathematical model; Build a state of charge management module to implement SOC upper and lower limit management logic; Conduct grid security assessments and integrate them into electric vehicle charging station models.

2. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 1, characterized in that: The main components of the electric vehicle charging pile model include voltage response modeling, frequency response modeling, charge state management modeling and safety assessment.

3. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 2, characterized in that: The construction of the voltage response mathematical model includes calculating a low voltage response coefficient and calculating a high voltage response coefficient; The low voltage response coefficient and the high voltage response coefficient are calculated as follows: F vl =K vt01 with i VL1 (VV to )+z u VL1 Among them, K vt01 The voltage slope of the low voltage response part; It is the pointer of voltage in low voltage area; The voltage is not in the low voltage area. t0 is the voltage trip response curve point 0; V is the voltage amplitude connected to the AC power grid; V t1 is the voltage trip response curve point 1; F vh =K vt23 with i VL2 (VV t2 )+z l VL2 Among them, K vt23 The voltage slope of the high voltage response part; The pointer indicates that the voltage is in the high voltage area; The voltage is not in the high voltage area. t2 is the voltage trip response curve point 2; V t3 It is point 3 of the voltage trip response curve.

4. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 3, characterized in that: The frequency response mathematical model includes calculating the low frequency response coefficient and the high frequency response coefficient, and the formula is as follows: F fl =K ft01 z i FL1 (F-F to )+z u FL1 Among them, K ft01 is the frequency slope of the low frequency response part; It is the pointer of frequency in low frequency area; The frequency is not in the low frequency area. t0 is the frequency trip response curve point 0; F t1 is the frequency tripping response curve point 1; F is the frequency value of the connected AC power grid; F fh =K ft23 z i FL2 (F-F t2 )+z l FL2 Among them, K ft23 is the frequency slope of the high frequency response part; It is the pointer of frequency in high frequency area; The frequency is not in the high frequency area. t3 This is point 3 of the V frequency trip response curve.

5. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 4, characterized in that: Active current command value I of electric vehicle charging pile pcmd and reactive current command value I qcmd The generation process is as follows:

6. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 5, characterized in that: The SOC upper and lower limit management logic includes: When the state of charge of the electric vehicle reaches the upper limit SOC max When the electric vehicle stops charging and enters the discharge state, I pmin Setting it to 0 limits the electric vehicle to the discharge state; When the state of charge of the electric vehicle reaches the lower limit SOC min When the electric vehicle stops discharging, it can only enter the charging state. pmax Set to 0 to limit the electric vehicle to the charging state; pmin Active power command value I pcmd The lower limit of I pmax Active power command value I pcmd upper limit.

7. The electric vehicle charging pile modeling method for the distribution network dynamic simulation platform according to claim 6, characterized in that: The charge state management part modeling includes: When the electric vehicle is charging: SOC=SOC ini -P elect ×EtaC(P elect <0) When the electric vehicle is in a discharging state: SOC=SOC ini -P elect ×EtaD(P elect >0) Among them, EtaC is the charging efficiency, EtaD is the discharging efficiency, SOC ini It is the initial state of charge of the electric vehicle; The state of charge (SOC) of electric vehicles should comply with the following constraints: SOC min ≤SOC≤SOC max The constraints of the electric vehicle's state of charge on the charging and discharging power are as follows: SOC≥SOC max I pmin =0 SOC≤SOC min I pmax =0。 8. An electric vehicle charging pile modeling system for a distribution network dynamic simulation platform, based on the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform according to any one of claims 1 to 7, characterized in that: Also includes, Charging pile structure analysis module, used to determine the main components of the electric vehicle charging pile according to the functional structure of the electric vehicle charging pile; Voltage response module function, used to build voltage response mathematical model; Frequency response module, used to set frequency trip response curve points and establish frequency response mathematical model; The state of charge management module function is used to implement the SOC upper and lower limit management logic; The grid security assessment module is used to conduct grid security assessment and integrate it into the electric vehicle charging pile model.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the electric vehicle charging pile modeling method for a distribution network dynamic simulation platform according to any one of claims 1 to 7 are implemented.

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