V2g charging station control method and system based on reverse power flow suppression, equipment and medium

Abstract

The application discloses a V2G charging station control method and system based on reverse power flow suppression, equipment and a medium, relates to the technical field of power distribution network operation control and vehicle-to-grid interaction, and comprises the following steps: taking reverse power flow suppression as a priority, considering the active power, reactive power and vehicle SOC dynamic problems of the charging and discharging unit, constructing a station rolling optimization model, calculating the set values of the active power and reactive power of each charging and discharging unit according to the station rolling optimization model; when the power reverse sending at the point of common coupling is over the limit, the absorption task is allocated based on the fair weight and the reverse sending over-limit amount, and the active power set value is adjusted. By taking the suppression of the PCC reverse power flow as a priority and guaranteeing the operation target of the power distribution network and the station, the station rolling optimization model of the V2G charging station is constructed, the power quality, equipment life and operation compliance are guaranteed, the absorption task is proportionally allocated among the charging and discharging units according to the fair weight, the station-level power is ensured to return to the permitted interval in time, and the solving capacity and response speed for sudden disturbances are improved.

Description

Technical Field

[0001] This invention relates to the field of power distribution network operation control and vehicle-to-grid interaction technology, and in particular to a V2G charging station control method, system, equipment and medium based on reverse power flow suppression. Background Technology

[0002] With the widespread adoption of distributed photovoltaic and wind power on the distribution side and the rapid popularization of electric vehicles, charging stations have evolved from traditional unidirectional loads into station-level resources with bidirectional energy exchange capabilities. V2G sites can generate revenue by discharging into the grid during peak electricity price periods, and can also absorb surplus power locally during periods of high renewable energy output or low prices. However, when the overall load in the distribution area is low and the local renewable energy output is high, the combined power of the site and surrounding distributed power sources may exceed the local absorption capacity, causing the power direction at the point of common coupling (PCC) to rise, forming a reverse power flow. Reverse power flow leads to voltage rise at the site and adjacent feeders, frequent tap changer and capacitor operation, overload of upstream equipment or protection setting mismatch, and may violate the contractual upper limit of reverse power transmission on the dispatch side; it poses risks to power quality, equipment lifespan, and operational compliance. Summary of the Invention

[0003] Therefore, it is necessary to propose a V2G charging station control method, system, equipment, and medium based on reverse power flow suppression to address the above issues, so as to ensure power quality, equipment lifespan, and operational compliance, and improve the ability to resolve and respond to sudden disturbances.

[0004] To achieve the above objectives, the first aspect of this application provides a V2G charging station control method based on reverse power flow suppression, wherein there is a communication connection between the backbone side, the feeder side, and the station interior side. The backbone side is the power grid and distribution control system upstream of the point of common coupling. The feeder side is the distribution feeder and / or transformer area connecting the upstream substation and the V2G charging station, and the local monitoring and control device for the distribution feeder and / or transformer area. The station interior side is the V2G charging station, which includes several charging and discharging units and a station-level control system. The method is applied to the station-level control system, and the method includes: When communication between the main side, the feeder side, and the station side is normal, the power flow operation constraints and electricity price constraints of the main side, as well as the sensitivity parameters and power feedback limit of the feeder side are obtained. The sensitivity parameters are the sensitivity coefficients of the node voltage to the active and reactive power within the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder. Prioritizing reverse power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's SOC into a convex optimization problem. An in-station rolling optimization model for the V2G charging station is constructed, and the set values ​​of active and reactive power of each charging and discharging unit in the next time period are calculated based on the power flow operation constraints, the electricity price constraints, the sensitivity parameters, the power backfeed upper limit, and the in-station rolling optimization model. Real-time monitoring of the operation of each of the charging and discharging units at the current time period's active / reactive power set values, and whether the power backflow at the common connection point exceeds the limit; When the power backfeed exceeds the limit at the common connection point, the backfeed excess amount of the V2G charging station is obtained, and based on the fair weight and the backfeed excess amount, absorption tasks are allocated among the currently adjustable target charging and discharging units. The active power setting value of the target charging and discharging unit is adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setting values ​​corresponding to the current time period.

[0005] Furthermore, prioritizing reverse power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's State of Charge (SOC) into a convex optimization problem, constructing an in-station rolling optimization model for the V2G charging station. This specifically includes: The weights of six control indicators for the V2G charging station are set according to preset priorities: over-limit reverse power, node voltage deviation, SOC target deviation, charging and discharging fairness, battery degradation cost, and incentive benefits / electricity cost. Among them, the penalty for over-limit reverse power is set to the highest priority. The objective function is constructed based on the six control indicators and their corresponding weights, and the in-station rolling optimization model of the V2G charging station includes the objective function.

[0006] Furthermore, the objective function is expressed as:

[0007] In the formula, The comprehensive optimization index is the in-station rolling optimization model of the V2G charging station; The weighting coefficient for the penalty of exceeding the limit in the reverse current flow; N The time span of each control cycle, k For any time period within the control cycle; For the first k Power at the common connection point during each time period; For the first k The upper limit of power feedback for each time period; The node voltage deviation penalty weighting coefficient; The voltage deviation weighting matrix for node voltages; For the first k The node voltage vector of the grid-connected node in each time period; This is the preset node rated voltage vector; For the first k The predicted offset of node voltage for each time period; The penalty weighting coefficient for SOC underachievement; This refers to the set of charging and discharging units in the V2G charging station. i For any one of the charge / discharge units in the set of charge / discharge units, For the first i The soft variable indicating that the SOC of the vehicle corresponding to each charging and discharging unit is insufficient at the expected departure time or the corresponding evaluation time. The weighting coefficients for the fairness of the service item; For the first i The fairness weighting coefficient for each charging / discharging unit corresponding to the vehicle; For the first i Each charging / discharging unit corresponds to the vehicle's current or predicted SOC; For the first i The estimated departure time or corresponding evaluation time of the vehicle corresponding to each charging / discharging unit; For the first i The target SOC of the vehicle at the expected departure time for each charging / discharging unit; This represents the weighting coefficient for the battery degradation cost item. , The respective i Each charging / discharging unit corresponds to the vehicle in the charging direction. and discharge direction The degradation cost coefficient; For the first k The first time period i The active power of each charging and discharging unit; The weighting coefficient for the incentive revenue / electricity cost item; For electricity price / incentives; The interval between two adjacent control cycles. , .

[0008] Furthermore, the allocation of absorption tasks among the currently adjustable target charging and discharging units based on fair weights and the backfeed excess amount, and the adjustment of the active power setpoint of the target charging and discharging units, specifically includes: Based on the difference between the current or predicted SOC of the vehicle controlled by each charging and discharging unit of the V2G charging station and the target SOC at the expected departure time or the corresponding evaluation time, the SOC underestimation amount of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time is determined. The weights of each charging and discharging unit are obtained based on the SOC underestimation of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time and the preset adjustment coefficient. Based on the current adjustable margin of the target charge and discharge unit, the weight of each charge and discharge unit, and the active power to be absorbed proportionally according to the over-limit amount of the reverse transmission, the active power adjustment amount of each target charge and discharge unit is obtained. The active power setting value of the target charging and discharging unit is updated based on the active power adjustment amount of each target charging and discharging unit and the active power setting value of the target charging and discharging unit, so as to obtain the adjusted active power setting value of the target charging and discharging unit.

[0009] Furthermore, before obtaining the active power adjustment amount of each target charging and discharging unit by proportionally allocating the active power to be absorbed based on the current adjustable target charging and discharging unit's adjustment margin, the weight of each charging and discharging unit, and the reverse transmission excess amount, the method further includes: Obtain the maximum active power and active power setting value of each charging and discharging unit; Based on the maximum active power capacity and active power setting value of the charging and discharging unit, the adjustment margin of each charging and discharging unit is determined, and the charging and discharging unit with an adjustment margin greater than the preset power threshold is taken as the target charging and discharging unit that can be adjusted up.

[0010] Furthermore, the V2G charging station also includes a local testing device, and the method further includes: When communication between the station side and the main trunk side and the feeder side is abnormal, the local measured voltage of the charging gun access point of each charging and discharging unit is obtained by the local measured device. The two-stage power logic operates based on local voltage. The active power setting value of each charging and discharging unit is determined according to the local measured voltage at the charging gun access point of each charging and discharging unit and the preset upper and lower limits of the node voltage, voltage threshold, slope coefficient and maximum charging capacity. Based on the logic of maintaining reactive power droop, the reactive power setting value of each charging and discharging unit is determined according to the local measured voltage, active power setting value, and preset maximum allowable apparent power, reactive power droop coefficient, and reference voltage of the charging gun access point of each charging and discharging unit, so that each charging and discharging unit of the V2G charging station operates based on the active and reactive power setting values ​​corresponding to the current time period.

[0011] Furthermore, the active power setting value of the charging and discharging unit is determined by the following formula:

[0012] In the formula, For the first time in the current control cycle The active power command value of each charging and discharging unit; For the first The reference active power value for each charging and discharging unit; For the first Maximum charging power of each charging / discharging unit; For the first Locally measured voltage at the charging gun connection point of each charging / discharging unit; For the first The upper voltage threshold of each charge / discharge unit; For the first The voltage threshold of each charge / discharge unit; , These are the upper and lower limits of the allowable node voltage, respectively; This is the active power-voltage slope coefficient for the high voltage section. This represents the active power-voltage slope coefficient in the low voltage section.

[0013] To achieve the above objectives, a second aspect of this application provides a station-level control system for V2G charging stations based on reverse power flow suppression, the system comprising: The data acquisition unit is used to acquire the power flow operation constraints and electricity price constraints of the backbone side, as well as the sensitivity parameters and power feedback upper limit of the feeder side, when the communication between the backbone side, the feeder side and the station side is normal. The sensitivity parameters are the sensitivity coefficients of the node voltage to the active and reactive power in the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder. The power prediction unit is used to prioritize reverse power flow suppression, dynamically unify the active and reactive power of each charging and discharging unit in the V2G charging station with the vehicle's SOC into a convex optimization problem, construct the in-station rolling optimization model of the V2G charging station, and calculate the set values ​​of active and reactive power of each charging and discharging unit in the next time period based on the power flow operation constraints, the electricity price constraints, sensitivity parameters, the upper limit of power back transmission, and the in-station rolling optimization model. The operation monitoring unit is used to monitor in real time whether the power backflow at the common coupling point exceeds the limit under the active / reactive power setpoints of each of the charging and discharging units in the current time period; when the power backflow at the common coupling point exceeds the limit, the backflow excess amount of the V2G charging station is obtained, and based on the fair weight and the backflow excess amount, absorption tasks are allocated among the currently adjustable target charging and discharging units, and the active power setpoints of the target charging and discharging units are adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setpoints corresponding to the current time period.

[0014] To achieve the above objectives, a third aspect of this application provides a computer-readable storage medium storing a computer program that, when executed by a processor, causes the processor to perform the steps of the method described in the first aspect.

[0015] To achieve the above objectives, a fourth aspect of this application provides a computer device including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor performs the steps of the method described in the first aspect.

[0016] The embodiments of the present invention have the following beneficial effects: This invention proposes a V2G charging station control method based on reverse power flow suppression. The method establishes communication connections between the main branch, feeder side, and station interior. The main branch is the power grid and distribution control system upstream of the point of common coupling. The feeder side consists of the distribution feeder and / or transformer substations connecting the upstream substation and the V2G charging station, along with local monitoring and control devices for the feeder and / or substations. The station interior is the V2G charging station, which includes several charging and discharging units and a station-level control system. The method is applied to the station-level control system and includes: when communication between the main branch, feeder side, and station interior is normal, acquiring the power flow operation constraints and electricity price constraints of the main branch, as well as the sensitivity parameters and power backflow limit of the feeder side. The sensitivity parameter is the sensitivity coefficient of the node voltage to the active and reactive power within the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder. The method then uses reverse power flow suppression... Prioritizing power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's State of Charge (SOC) into a convex optimization problem. An in-station rolling optimization model for the V2G charging station is constructed, and the setpoints for the active and reactive power of each charging and discharging unit in the next time period are calculated based on power flow constraints, electricity price constraints, sensitivity parameters, power backflow limits, and the in-station rolling optimization model. Real-time monitoring is conducted to determine if the power backflow at the point of common coupling (PCC) exceeds the limit under the current active / reactive power setpoints of each charging and discharging unit. If the power backflow at PCC exceeds the limit, the amount of backflow exceeding the limit for the V2G charging station is obtained. Based on fair weights and the amount of backflow exceeding the limit, absorption tasks are allocated among the currently adjustable target charging and discharging units, and the active power setpoints of the target charging and discharging units are adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setpoints corresponding to the current time period. This invention constructs an in-station rolling optimization model for V2G charging stations by prioritizing the suppression of PCC reverse power flow while ensuring operational objectives such as distribution network constraints and vehicle SOC targets at expected departure times. This in-station rolling optimization model reduces the frequency of tap changer and reactive power equipment operation, ensuring power quality, equipment lifespan, and operational compliance. Furthermore, when reverse power flow exceeds limits, absorption tasks are proportionally allocated among charging and discharging units based on fair weights, ensuring that station-level power returns to the permissible range immediately. This method can operate without external communication, improving the ability to resolve sudden disturbances and response speed. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] in: Figure 1 This is a flowchart illustrating the V2G charging station control method based on reverse power flow control in an embodiment of the present invention. Figure 2 This is a structural block diagram of a station-level control system for a V2G charging station based on reverse power flow suppression, according to an embodiment of the present invention. Figure 3 This is an internal structural diagram of a computer device in an embodiment of the present invention. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Existing technologies largely rely on single-layer target-driven approaches, such as driving V2G discharge solely based on electricity prices, using only local constraints based on station voltage closed-loop, or limiting backfeed through static output limits. These methods often ignore the capacity boundaries of the feeder and backbone layers, lacking robust buffering against uncertainties; simultaneously, they fail to incorporate user-side experience (SOC compliance, fairness, and waiting time) into a unified optimization framework. Once communication with the feeder layer fails, traditional centralized or decentralized control may lose coordination, leading to breaches of safety boundaries or a significant decline in user experience. Therefore, there is an urgent need for a charging station control method that can dynamically balance the three layers of objectives and automatically degrade while maintaining backfeed suppression capabilities in the event of communication failures.

[0021] This invention proposes a V2G (Vehicle-to-Grid) charging station control method prioritizing reverse power flow suppression at the common point of connection (PCC) of the distribution network. This method achieves hierarchical coordination and degraded adaptive control of charging and discharging power and reactive power support, taking into account the distribution network voltage and current safety boundaries, the upper limit of PCC reverse power, the SOC target and fairness of user vehicles, and the charging queuing experience. It is applicable to medium and low voltage distribution networks containing distributed power sources and large-scale charging facilities.

[0022] This invention employs a three-layer collaborative architecture: station-feeder-backbone. Communication connections exist between the backbone side, feeder side, and station-inside side. The backbone side, representing the power grid and distribution control system upstream of the point of common coupling (PCC), is responsible for issuing power flow and electricity price constraints to PCC. The feeder side comprises the distribution feeders and / or transformer substations connecting the upstream substation and the V2G charging station, along with local monitoring and control devices for these feeders and / or substations. These devices calculate the available reverse power margin for the station and provide parameters such as voltage and current sensitivity, based on given backbone side constraints and considering the operation of other loads and distributed power sources along the feeder. The station-inside side represents the V2G charging station, which includes several charging and discharging units and a station-level control system. This system is responsible for implementing rolling optimization control and second-level power allocation based on the aforementioned constraints and parameters. The V2G charging station control method based on reverse power flow suppression proposed in this invention is applied to the station-level control system; details can be found in the following references. Figure 1 , Figure 1 This is a flowchart illustrating the V2G charging station control method based on reverse power flow control in an embodiment of the present invention. The method includes: S100. When communication between the main side, feeder side and station side is normal, the power flow operation constraints and electricity price constraints of the main side are obtained, as well as the sensitivity parameters and power feedback upper limit of the feeder side. Among them, the sensitivity parameter is the sensitivity coefficient of the node voltage to the active and reactive power in the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder.

[0023] In this embodiment, the backbone side provides power flow constraints and electricity price constraints, including the time limit curve of PCC back-feeding power and price / incentive signals, according to the power grid operation plan; the feeder side predicts the local net load and renewable output without charging stations based on historical and real-time data, gives the power back-feeding limit (back-feeding margin) at PCC, and calculates the sensitivity coefficient of the station node voltage to the active and reactive power in the station through a linearized power flow or data-driven model, and then broadcasts the back-feeding limit and sensitivity parameters to the station layer. It is understandable that the backflow limit on the backbone side is essentially also the backflow power limit, but it refers to the maximum allowable reverse power flow index issued by the dispatching side / backbone side from the perspective of the entire network or region, for that grid connection point. The backflow power limit at the PCC, on the other hand, is a local constraint value that can be executed at the site, calculated and tightened by the feeder side based on the backflow limit on the backbone side, taking into account factors such as the prediction of other loads and distributed power sources on this feeder, voltage / current constraints, and uncertainty margins. Numerically, it is no greater than the backbone side limit. In extreme cases, the two can be equal, but conceptually, the former is the "original boundary given by the superior," while the latter is an "effective constraint for direct use in site optimization." The dispatching side can be understood as a superior control system such as the grid dispatching / distribution network master station / aggregation control platform located upstream of the distribution feeders and charging stations. It is responsible for formulating and issuing global constraints such as the backflow power limit at the PCC, electricity price, and grid operation mode from the perspective of the entire network or region, and essentially belongs to the category of the "backbone side."

[0024] When communication between the main trunk side, feeder side, and station interior side is normal, the station interior layer can receive power flow operation constraints and electricity price constraints from the main trunk side, as well as sensitivity parameters and power feedback limits from the feeder side, in order to perform station interior control based on these constraints and parameters.

[0025] S200 prioritizes reverse power flow suppression, dynamically unifying the active and reactive power of each charging and discharging unit in the V2G charging station with the vehicle's SOC into a convex optimization problem, constructing an in-station rolling optimization model for the V2G charging station, and calculating the set values ​​of active and reactive power of each charging and discharging unit in the next time period based on power flow operation constraints, electricity price constraints, sensitivity parameters, power backfeed upper limit, and the in-station rolling optimization model.

[0026] In this embodiment, the station-level control system on the in-station side prioritizes suppressing PCC backfeed. It dynamically unifies the active and reactive power of each charging and discharging unit with the vehicle's SOC into a convex optimization problem, constructing a rolling optimization model with backfeed suppression as the priority. The setpoints for the active and reactive power of each charging and discharging unit in the next time period are solved by rolling optimization using power flow constraints, electricity price constraints, sensitivity parameters, and power backfeed upper limits.

[0027] S300 monitors in real time whether the power backflow at the common coupling point exceeds the limit under the current active / reactive power setpoints of each charging and discharging unit. If the power backflow at the common coupling point exceeds the limit, the backflow excess amount of the V2G charging station is obtained, and based on the fair weight and the backflow excess amount, the absorption task is allocated among the target charging and discharging units that can be adjusted, and the active power setpoints of the target charging and discharging units are adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setpoints corresponding to the current time period.

[0028] In this embodiment, considering the possibility of communication anomalies during the control cycle, such as feeder communication anomalies, which mainly refer to the interruption or abnormality of the communication link between the station side and the feeder side, the station side is unable to obtain or update the upper limit of the reverse power, voltage / current sensitivity parameters, and related data such as the net load of the transformer area and the prediction of distributed power sources provided by the feeder side in real time.

[0029] To ensure that backfeed suppression priority is maintained even under rapid disturbances and communication anomalies, a high-frequency margin closed-loop allocator operates in the system: it monitors PCC power in real time, and if backfeed exceeds the limit at the point of common coupling under the current active / reactive power setpoints, it allocates the absorption task proportionally among the currently adjustable units according to fair weights, immediately pulling the station-level power back to the allowable range, so as to ensure the station's ability to resolve sudden disturbances and its response speed.

[0030] The V2G charging station control method based on reverse power flow control proposed in this invention prioritizes suppressing PCC reverse power flow while ensuring operational objectives such as distribution network constraints and vehicle SOC targets at expected departure times. This allows for the construction of an in-station rolling optimization model for the V2G charging station. This in-station rolling optimization model reduces the frequency of tap changer and reactive power equipment operation, ensuring power quality, equipment lifespan, and operational compliance. Furthermore, when reverse power flow exceeds limits, absorption tasks are proportionally allocated among charging and discharging units based on fair weights, ensuring that station-level power returns to the permissible range immediately. This method operates without external communication, improving the ability to resolve sudden disturbances and response speed.

[0031] In this embodiment of the invention, the symbols and inputs in the control process are defined as follows: Forward charging is Discharge is The active and reactive power at the station level are as follows:

[0032] The power at the PCC is represented by the symbol convention of "positive for purchasing power from the upstream and negative for reverse transmission":

[0033] in, This represents the predicted net value of the net load and renewable energy output of the transformer substation excluding charging stations.

[0034] In one embodiment of the present invention, S200, prioritizing reverse power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's SOC into a convex optimization problem, constructing an in-station rolling optimization model for the V2G charging station, specifically including: S210. Set the weights of six control indicators for V2G charging stations according to preset priorities: over-limit reverse power, node voltage deviation, SOC target deviation, charging and discharging fairness, battery degradation cost, and incentive benefits / electricity cost. Among them, the penalty for over-limit reverse power is set to the highest priority.

[0035] In this embodiment, multiple control objectives such as "backflow suppression, voltage safety, user SOC and fairness, battery life and economic benefits" are weighed simultaneously under given constraints, and priority is reflected by weights.

[0036] In one feasible embodiment, the control of V2G charging stations includes six control indicators: V2G charging station reverse power over-limit, node voltage deviation, SOC target deviation, charging and discharging fairness, battery degradation cost, and incentive benefits / electricity cost. Each indicator has its own weight to reflect the priority of each indicator.

[0037] Specifically, the reverse current over-limit penalty weight coefficient is a positive scalar quantity tuned offline by the station controller / operator. Its magnitude is adjusted through simulation or operational experience to ensure that "reverse transmission without exceeding limits" has the highest priority in the target. The node voltage deviation penalty weight coefficient is also a positive scalar quantity tuned offline, used to control the weight of the voltage deviation item in the target to ensure voltage safety. The SOC under-achievement penalty weight coefficient is used to measure the severity of the user's target SOC not being met, and is a positive scalar quantity set offline by the operator based on user satisfaction requirements. The service fairness item weight coefficient is a value obtained through offline tuning, used to control the importance of fairness indicators in the overall target. The battery degradation cost item weight coefficient is set offline by combining battery life value, operating costs, etc., to balance battery life and immediate benefits. The incentive benefit / electricity cost item weight coefficient is obtained by the operator through offline tuning based on the trade-off between economy and safety, and user experience.

[0038] S220. Based on the six control indicators and their corresponding weights, an objective function is constructed. The in-station rolling optimization model of V2G charging stations includes an objective function.

[0039] In this embodiment, the objective function is aggregated from the V2G charging station's reverse power over-limit, node voltage deviation, SOC target deviation, charge-discharge fairness, battery degradation cost, and incentive benefits / electricity cost; the constraint set includes power capability, SOC dynamics, voltage / current safety boundary, and reverse power upper limit with uncertainty margin, etc.

[0040] In a feasible embodiment, the objective function is expressed as:

[0041] In the formula, The comprehensive optimization index for the rolling optimization model within a V2G charging station; The weighting coefficient for the penalty of exceeding the limit in the reverse current flow; N The time span of each control cycle, k For any time period within the control cycle; For the first k Power at the common connection point during each time period; For the first k The upper limit of power feedback for each time period; The node voltage deviation penalty weighting coefficient; The voltage deviation weighting matrix for node voltages; For the first k The node voltage vector of the grid-connected nodes in each time period, where the superscript... Represents a node and parting ; This is the preset node rated voltage vector; For the first k The predicted offset of node voltage for each time period; The penalty weighting coefficient for SOC underachievement; This refers to the collection of charging and discharging units in a V2G charging station. i For any charge / discharge unit in the set of charge / discharge units, For the first i The soft variable indicating that the SOC of the vehicle corresponding to each charging and discharging unit is insufficient at the expected departure time or the corresponding evaluation time. The weighting coefficients for the fairness of the service item; For the first i The fairness weighting coefficient for each charging / discharging unit corresponding to the vehicle; For the first i Each charging / discharging unit corresponds to the vehicle's current or predicted SOC; For the first i The estimated departure time or corresponding evaluation time of the vehicle corresponding to each charging / discharging unit; For the first iThe target SOC of the vehicle at the expected departure time for each charging / discharging unit; This represents the weighting coefficient for the battery degradation cost item. , The respective i Each charging / discharging unit corresponds to the vehicle in the charging direction. and discharge direction The degradation cost coefficient; For the first k The first time period i The active power of each charging and discharging unit; The weighting coefficient for the incentive revenue / electricity cost item; For electricity price / incentives; The interval between two adjacent control cycles. , .

[0042] Specifically, the first term in the objective function imposes a strong penalty on the portion exceeding the reverse power limit, thus placing "reverse power flow without exceeding the limit" as the highest priority; the second term penalizes node voltage deviations from the rated value to ensure the distribution network voltage level; the third term, by weighting the SOC underachievement, pushes each vehicle to reach the target SOC at the expected departure time; the fourth term aims to reduce service differences between vehicles and achieve charging and discharging fairness; the fifth term characterizes the battery degradation cost caused by charging and discharging; and the sixth term reflects electricity price revenue or electricity cost, enabling the optimization to maximize economic efficiency while meeting the aforementioned safety and user indicators. By setting the weight coefficients for each term, these objectives are unified within a solvable convex optimization framework, resulting in an in-station power trajectory that balances safety and economy.

[0043] Voltage deviation weighting matrix of node voltages Typically a diagonal matrix, it is used to assign different weights to voltage deviations at different nodes or in different phases. It is set offline according to the distribution network topology and the importance of key nodes, for example, giving greater weight to the node where the PCC is located.

[0044] Node rated voltage vector This represents the desired voltage level, given by the system's rated voltage and operating requirements, and is generally a constant.

[0045] No. k Predicted offset of node voltage for each time period The first power flow model obtained from the linearized power flow model The predicted offset of node voltage for each time period. The linearized relationship between node voltage and station-level power can be approximated by data identification as follows:

[0046] In the formula, Indicates the first The station-level active / reactive power of the V2G charging station at that node during a certain time period; , This is the sensitivity coefficient of node voltage to station-level active and reactive power. It is obtained by fitting offline power flow simulation or online measurement data near a given network structure and operating point, i.e., using multiple sets of... Data fitting linear relationship ; Indicates the first The node voltage reference offset caused by factors such as other loads and distributed power sources within the transformer area during each time period is obtained during the aforementioned data identification, or is calculated and issued by the feeder side based on the power prediction of the transformer area excluding charging stations. k Predicted offset of node voltage for each time period A linear approximation relationship between node voltage offset and the active and reactive power of the charging station is presented. Its function is to transform the distribution network voltage constraint into a station-level power constraint, which is then used in the subsequent in-station rolling optimization (MPC) model optimization of the V2G charging station. and will The linear model is used to calculate, thus requiring the obtained... The combination will not cause the node voltage to exceed the upper or lower limits; at the same time, it can also be adjusted in the objective function. A penalty is applied to reduce voltage deviation. In summary, the calculation... The goal is to explicitly ensure the safe operation of distribution network node voltages while performing reverse power flow suppression and power optimization allocation.

[0047] No. i The fairness weighting coefficient for each charging / discharging unit corresponding to the vehicle This value is used to reflect the relative weight of different vehicles in the fairness evaluation. It can be uniformly set to 1, or it can be updated offline or online based on information such as the vehicle's historical charging and discharging service deviation and priority.

[0048] No. i The soft variable indicating that the State of Charge (SOC) of the vehicle corresponding to each charging / discharging unit is below the expected departure time or the corresponding evaluation time. ,satisfy , This refers to the vehicle's expected departure time or the corresponding evaluation time. Vehicle SOC dynamics:

[0049] In the formula, For the first i The SOC of each charge / discharge unit at the next moment. For the first i The SOC of each charge / discharge unit at the current moment. For vehicle battery capacitors, , For vehicle battery round-trip efficiency.

[0050] This invention provides an embodiment of a rolling optimization model for V2G charging stations that operates on a minute-by-minute basis to calculate the active and reactive power settings of each charging and discharging unit for the next time period.

[0051] Within the control cycle, the optimal active and reactive power are calculated for each charging and discharging unit, and the active and reactive power setpoints for each unit are determined. Furthermore, the state of charge (SOC) evolution of each vehicle can be derived from the aforementioned power sequence. SOC underachievement soft variable Quantities related to fairness are used to ensure the feasibility of constraints and the calculation of each term in the objective function. SOC compliance deviation and fairness metrics are introduced into the objective function, and adjustable weights and parameter ranges are used to adapt to service strategies at different stations. While suppressing backfeeding, vehicles have a higher probability of meeting standards at their expected departure time, thus controlling queuing. Compared to greedy strategies that ignore fairness, this invention can reduce the incidence of extreme undercharging of individual vehicles and improve overall satisfaction.

[0052] In one embodiment of the present invention, S300, real-time monitoring of whether the power backflow at the point of common coupling exceeds the limit under the set active / reactive power of each charging and discharging unit at the current time period, specifically includes: After the MPC obtains the optimized solution (active and reactive power setpoints for each charging and discharging unit), during the implementation of the optimized solution, the measured power of the PCC is monitored at second-level intervals to determine the amount of reverse power exceeding the limit.

[0053] In the formula, The PCC's reverse transmission exceeded the limit. This is the upper limit of the reverse power of the PCC. This represents the measured power of the PCC.

[0054] The dispatching side or feeder side provides the upper limit of the reverse transmission at the PCC. To mitigate uncertainty, consider the deviation in photovoltaic power generation. Deviation under load Constructing a robust form:

[0055] Among them, photovoltaic up-deviation refers to the portion of photovoltaic output that is higher than the predicted value during a certain period, and can be defined as:

[0056] This means that only the positive deviation upwards is used to characterize the error on the side where photovoltaic power generation exceeds expectations, which would increase the risk of backfeeding.

[0057] Load deviation refers to the portion of the actual load of a transformer area that is lower than the predicted load during a certain period, and can be written as:

[0058] That is, only the downward negative deviation is used to characterize the error on the side where the load is smaller than expected, which will also lead to an increase in reverse feed.

[0059] By constructing a robust form to impose a "robust back-feeding power upper limit constraint" on the active power at PCC, a nominal back-feeding upper limit is given by the dispatch / feeder side. A safety margin is then constructed using photovoltaic up-off deviation and load down-off deviation, tightening the "maximum allowable back-feeding power" under the most unfavorable prediction error. Therefore, this constraint requires that, considering the possibility of increased photovoltaic power generation and decreased load, the actual active power at PCC must not exceed the allowable back-feeding upper limit, serving as a hard constraint condition in subsequent optimization. If only hard constraints are used, it can be set as follows: If softening is desired, then an over-limit penalty is added to the objective function.

[0060] This invention employs joint modeling of the PCC backfeed upper limit and voltage / current boundaries to ensure that the backfeed power does not exceed the constraint value during V2G interactions at the charging station, in a mathematically verifiable manner. In the presence of prediction bias and disturbances, the robust relaxation term provides a clear safety margin, significantly reducing the risk of exceeding limits.

[0061] In one embodiment of the present invention, S300, based on fair weighting and reverse transmission excess, absorption tasks are allocated among the currently adjustable target charging and discharging units, and the active power setpoint of the target charging and discharging units is adjusted, specifically including: S310. Based on the difference between the current or predicted SOC of the vehicle controlled by each charging and discharging unit of the V2G charging station and the target SOC at the expected departure time or the corresponding evaluation time, determine the SOC underachievement amount of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time.

[0062] In this embodiment, the vehicle's target SOC underestimation is determined by the difference between the vehicle's current or predicted SOC controlled by the charging and discharging unit and the target SOC at the expected departure time or the corresponding evaluation time.

[0063] Specifically, the first i The SOC underestimation level of the vehicle corresponding to each charging / discharging unit is It is understandable that the SOC level is insufficient. It is a quantity calculated directly from the data, determined by the difference between the vehicle's current or predicted SOC and the target SOC at the expected departure / evaluation time. SOC underachievement is a soft variable. It is a slack variable in optimization problems.

[0064] S320. Based on the SOC underachievement of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time and the preset adjustment coefficient, the weight of each charging and discharging unit is obtained.

[0065] In this embodiment, the weight of each charging / discharging unit is determined by the following formula:

[0066] In the formula, The weight of the i-th charging / discharging unit; The preset adjustment coefficient is used to control the degree of influence of the vehicle's target SOC underachievement on the weight. The larger the value, the greater the weight and the higher the priority of the vehicle with the lower SOC in the reserve allocation. Its value is determined offline by the operator or station control based on simulation and operation experience. Generally, a positive dimensionless constant is selected, or it is determined by a compromise between "fairness improvement effect" and "weight change stability" through multiple simulations or trial runs.

[0067] S330. Based on the current adjustable margin of the target charge / discharge unit, the weight of each charge / discharge unit, and the over-limit of the reverse transmission, the active power to be absorbed is proportionally allocated to obtain the active power adjustment amount of each target charge / discharge unit.

[0068] In one embodiment, before obtaining the active power adjustment amount of each target charging and discharging unit, the method of determining the charging and discharging units that can be adjusted upwards includes: obtaining the maximum active power capacity and active power setting value of each charging and discharging unit; determining the adjustment margin of each charging and discharging unit based on the maximum active power capacity and active power setting value of the charging and discharging unit; and taking the charging and discharging units with an adjustment margin greater than a preset power threshold as the current target charging and discharging units that can be adjusted upwards.

[0069] Specifically, when the PCC's reverse discharge exceedance is greater than 0, a redistribution of the margin is required among the charge / discharge units. First, the over-adjustment margin for each charge / discharge unit must be determined:

[0070] In the formula, This represents the adjustment margin for the i-th charge / discharge unit. For the first time in the current control cycle The active power command value of each charging and discharging unit For the first The maximum charging power of each charging and discharging unit.

[0071] When the adjustment margin of the charge / discharge unit is greater than 0, the charge / discharge unit is taken as the target charge / discharge unit that can be adjusted up.

[0072] After identifying the target charge / discharge units that can be adjusted upwards, allocate the active power to each target charge / discharge unit proportionally, and determine the required active power to be absorbed:

[0073]

[0074] In the formula, This refers to the back-feeding excess amount calculated earlier, which is the total station-level active power that needs to be "increased in absorption / reduced in discharge" this time. The upsizing margin of the j-th charge / discharge unit represents the charging power that the unit can increase without exceeding the rated constraints. Total upside margin available for all charge / discharge units; This represents the total active power regulation amount actually allocated by the i-th charging and discharging unit in this operation. The weight of the i-th charging / discharging unit; This is the active power adjustment amount ultimately allocated to the i-th charging / discharging unit.

[0075] This invention introduces an in-station margin closed-loop distributor, enabling the system to maintain second-level correction capabilities in addition to minute-level optimization. When the power measured by the PCC exceeds the backfeed limit, the distributor quickly allocates absorption tasks among the units according to the upward adjustment margin-fair weight ratio formula, ensuring that the station-level power returns to the permissible range in an instant. This mechanism can operate without external communication, significantly improving the response speed to sudden disturbances.

[0076] S340. Update the active power setting value of the target charging and discharging unit according to the active power adjustment amount of each target charging and discharging unit and the active power setting value of the target charging and discharging unit to obtain the adjusted active power setting value of the target charging and discharging unit.

[0077] In this embodiment, the active power setting value of the target charging and discharging unit is updated based on the active power adjustment amount of each target charging and discharging unit and the active power setting value of the target charging and discharging unit, to obtain a new active power setting value for the target charging and discharging unit:

[0078] In the formula, The adjusted active power setting value for the target charging / discharging unit (the i-th charging / discharging unit). This represents the maximum discharge power amplitude of the i-th charging and discharging unit (the rated upper limit of the vehicle's power transmission to the grid). The maximum charging power amplitude of the i-th charging and discharging unit (the rated upper limit of the grid charging the vehicle).

[0079] In one embodiment of the present invention, when both the station control and the feeder lose communication, the gun-level controller independently operates a two-stage power-voltage logic and reactive power droop, autonomously converging to a safe state using local voltage over-limit direction sensing. Specifically, the V2G charging station also includes a local measurement device, and the method further includes: S410. When communication between the station side and the main trunk side and feeder side is abnormal, obtain the local measured voltage of the charging gun access point of each charging and discharging unit obtained by the local measured device.

[0080] In this embodiment, when communication between the station side and the main trunk side and feeder side is abnormal, the local measured voltage of the charging gun access point of each charging and discharging unit is obtained by using a local measured device.

[0081] S420 operates a two-stage power logic based on local voltage. It determines the active power setting value of each charging and discharging unit based on the local measured voltage at the charging gun access point of each charging and discharging unit and the preset upper and lower limits of the node voltage, voltage threshold, slope coefficient, and maximum charging capacity.

[0082] In this embodiment, the active power setting value of the charging and discharging unit is determined by the following formula:

[0083] In the formula, For the first time in the current control cycle The active power command value of each charging and discharging unit; For the first The reference active power value for each charging and discharging unit; For the first Maximum charging power of each charging / discharging unit; For the first Locally measured voltage at the charging gun connection point of each charging / discharging unit; For the first The upper voltage threshold of each charge / discharge unit; For the first The voltage threshold of each charge / discharge unit; , These are the upper and lower limits of the allowable node voltage, respectively; This is the active power-voltage slope coefficient for the high voltage section. This represents the active power-voltage slope coefficient in the low voltage section.

[0084] S430: Based on the reactive power droop logic, the reactive power setting value of each charging and discharging unit is determined according to the local measured voltage, active power setting value, and preset maximum allowable apparent power, reactive power droop coefficient, and reference voltage of the charging gun connection point of each charging and discharging unit, so that each charging and discharging unit of the V2G charging station operates based on the active and reactive power setting values ​​corresponding to the current time period.

[0085] In this embodiment, the reactive power is kept at a downward position:

[0086] In the formula, The reactive power droop factor is the voltage deviation. Converted to reactive power output, The reference voltage (usually the rated voltage) used for reactive power droop control; For the first The maximum permissible apparent power of each charge / discharge unit is constrained. Ensure that the rated capacity is not exceeded.

[0087] To enhance resilience, this invention employs a combined "reverse margin closed-loop allocation" and "gun-level power-voltage two-stage" strategy within the station layer during communication anomalies. This allows for rapid restoration of PCC power back to the allowable range without requiring uplink information. This invention achieves consistent control objectives under normal, abnormal, and extreme conditions, and provides detailed records and interfaces to support metering and settlement.

[0088] This invention employs rolling prediction for in-site optimization, with the execution end setting upper / lower limit projections and rate limits for reference values. To avoid impact, the proportional allocation of the margin closed loop uses only the currently adjustable margin at any time, naturally satisfying power feasibility; when running in parallel with reactive power droop, electrical safety is ensured through apparent power projection; the gun-stage degradation uses voltage threshold hysteresis to avoid frequent switching near the critical voltage.

[0089] This invention proposes a degradation control method combining two-stage power-voltage logic at the charging station level with reactive power droop. Even when station control or feeder communication is interrupted, a single charging unit can still determine the direction of absorption or restriction of discharge based on the local voltage, autonomously achieving a consistent backfeed suppression target. Unlike traditional shutdown or fixed-limit degradation, this solution can dynamically and continuously adjust according to the voltage situation, avoiding a decline in user experience caused by excessive conservatism.

[0090] In one embodiment of the present invention, a station-level control system for V2G charging stations based on reverse power flow suppression is also proposed, which can be found in [reference]. Figure 2 , Figure 2 This is a structural block diagram of a station-level control system for a V2G charging station based on reverse power flow suppression, according to an embodiment of the present invention. The system includes: The data acquisition unit 201 is used to acquire the power flow operation constraints and electricity price constraints of the backbone side, as well as the sensitivity parameters and power feedback upper limit of the feeder side when the communication between the backbone side, feeder side and station side is normal. The sensitivity parameter is the sensitivity coefficient of the node voltage to the active and reactive power in the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder.

[0091] The power prediction unit 202 is used to prioritize reverse power flow suppression, dynamically unify the active and reactive power of each charging and discharging unit in the V2G charging station with the vehicle's SOC into a convex optimization problem, construct an in-station rolling optimization model for the V2G charging station, and calculate the set values ​​of active and reactive power of each charging and discharging unit in the next time period based on power flow operation constraints, electricity price constraints, sensitivity parameters, power backfeed upper limit, and the in-station rolling optimization model.

[0092] The operation monitoring unit 203 is used to monitor in real time whether the power back-feeding at the common coupling point exceeds the limit under the operation of each charging and discharging unit with the active / reactive power setpoints in the current time period; when the power back-feeding at the common coupling point exceeds the limit, the back-feeding excess amount of the V2G charging station is obtained, and based on the fair weight and the back-feeding excess amount, the absorption task is allocated among the target charging and discharging units that can be adjusted, and the active power setpoints of the target charging and discharging units are adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setpoints corresponding to the current time period.

[0093] The station-level control system for V2G charging stations proposed in this invention prioritizes the suppression of PCC reverse power flow while ensuring operational objectives such as distribution network constraints and vehicle SOC targets at expected departure times. This enables the construction of an in-station rolling optimization model for the V2G charging station. Based on this model, the frequency of tap changer and reactive power equipment operation is reduced, ensuring power quality, equipment lifespan, and operational compliance. Furthermore, when reverse power flow exceeds limits, absorption tasks are proportionally allocated among charging and discharging units according to fair weights, ensuring that the station-level power returns to the permissible range immediately. This method can operate without external communication, improving the ability to resolve sudden disturbances and the response speed.

[0094] Figure 3 An internal structural diagram of a computer device according to one embodiment of the present invention is shown. This computer device can specifically be a terminal or a system. Figure 3As shown, the computer device includes a processor, memory, and network interface connected via a system bus. The memory includes a non-volatile storage medium and internal memory. The non-volatile storage medium stores an operating system and may also store a computer program. When executed by the processor, this computer program causes the processor to perform the steps in the above-described method embodiments. The internal memory may also store a computer program, which, when executed by the processor, causes the processor to perform the steps in the above-described method embodiments. Those skilled in the art will understand that... Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0095] In one embodiment, a computer device is provided, including a memory and a processor, the memory storing a computer program that, when executed by the processor, causes the processor to perform the steps in the above method embodiments.

[0096] In one embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, causes the processor to perform the steps in the above method embodiments.

[0097] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, storage, databases, or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory can include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM), or flash memory. Volatile memory can include random access memory (RAM) or external cache memory. By way of illustration and not limitation, RAM is available in various forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), dual data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link DRAM (SLDRAM), RAMbus direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and RAMbus dynamic RAM (RDRAM), etc.

[0098] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0099] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of this patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A V2G charging station control method based on reverse power flow suppression, characterized in that, The communication connection between the main side, feeder side, and station-inside side is as follows: the main side is the power grid and distribution control system upstream of the common connection point; the feeder side is the distribution feeder and / or transformer area connecting the upstream substation and the V2G charging station, and the local monitoring and control device for the distribution feeder and / or transformer area; the station-inside side is the V2G charging station, which includes several charging and discharging units and a station-level control system; the method is applied to the station-level control system; the method includes: When communication between the main side, the feeder side, and the station side is normal, the power flow operation constraints and electricity price constraints of the main side, as well as the sensitivity parameters and power feedback limit of the feeder side are obtained. The sensitivity parameters are the sensitivity coefficients of the node voltage to the active and reactive power within the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder. Prioritizing reverse power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's SOC into a convex optimization problem. An in-station rolling optimization model for the V2G charging station is constructed, and the set values ​​of active and reactive power of each charging and discharging unit in the next time period are calculated based on the power flow operation constraints, the electricity price constraints, the sensitivity parameters, the power backfeed upper limit, and the in-station rolling optimization model. Real-time monitoring of the operation of each of the charging and discharging units at the current time period's active / reactive power set values, and whether the power backflow at the common connection point exceeds the limit; When the power backfeed exceeds the limit at the common connection point, the backfeed excess amount of the V2G charging station is obtained, and based on the fair weight and the backfeed excess amount, absorption tasks are allocated among the currently adjustable target charging and discharging units. The active power setting value of the target charging and discharging unit is adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setting values ​​corresponding to the current time period.

2. The method as described in claim 1, characterized in that, Prioritizing reverse power flow suppression, the active and reactive power of each charging and discharging unit in the V2G charging station are dynamically unified with the vehicle's State of Charge (SOC) into a convex optimization problem, constructing an in-station rolling optimization model for the V2G charging station. Specifically, this includes: The weights of six control indicators for the V2G charging station are set according to preset priorities: over-limit reverse power, node voltage deviation, SOC target deviation, charging and discharging fairness, battery degradation cost, and incentive benefits / electricity cost. Among them, the penalty for over-limit reverse power is set to the highest priority. The objective function is constructed based on the six control indicators and their corresponding weights, and the in-station rolling optimization model of the V2G charging station includes the objective function.

3. The method as described in claim 2, characterized in that, The objective function is expressed as: In the formula, The comprehensive optimization index is the in-station rolling optimization model of the V2G charging station; The weighting coefficient for the penalty of exceeding the limit in the reverse current flow; N The time span of each control cycle, k For any time period within the control cycle; For the first k Power at the common connection point during each time period; For the first k The upper limit of power feedback for each time period; The node voltage deviation penalty weighting coefficient; The voltage deviation weighting matrix for node voltages; For the first k The node voltage vector of the grid-connected node in each time period; This is the preset node rated voltage vector; For the first k The predicted offset of node voltage for each time period; The penalty weighting coefficient for SOC underachievement; This refers to the set of charging and discharging units in the V2G charging station. i For any one of the charge / discharge units in the set of charge / discharge units, For the first i The soft variable indicating that the SOC of the vehicle corresponding to each charging and discharging unit is insufficient at the expected departure time or the corresponding evaluation time. The weighting coefficients for the fairness of the service item; For the first i The fairness weighting coefficient for each charging / discharging unit corresponding to the vehicle; For the first i Each charging / discharging unit corresponds to the vehicle's current or predicted SOC; For the first i The estimated departure time or corresponding evaluation time of the vehicle corresponding to each charging / discharging unit; For the first i The target SOC of the vehicle at the expected departure time for each charging / discharging unit; This represents the weighting coefficient for the battery degradation cost item. , The respective i Each charging / discharging unit corresponds to the vehicle in the charging direction. and discharge direction The degradation cost coefficient; For the first k The first time period i The active power of each charging and discharging unit; The weighting coefficient for the incentive revenue / electricity cost item; For electricity price / incentives; The interval between two adjacent control cycles. , .

4. The method as described in claim 1, characterized in that, The allocation of absorption tasks among the currently adjustable target charging and discharging units based on fair weighting and the backfeeding excess amount, and the adjustment of the active power setpoint of the target charging and discharging units, specifically includes: Based on the difference between the current or predicted SOC of the vehicle controlled by each charging and discharging unit of the V2G charging station and the target SOC at the expected departure time or the corresponding evaluation time, the SOC underestimation amount of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time is determined. The weights of each charging and discharging unit are obtained based on the SOC underestimation of the vehicle controlled by each charging and discharging unit at the expected departure time or the corresponding evaluation time and the preset adjustment coefficient. Based on the current adjustable margin of the target charge and discharge unit, the weight of each charge and discharge unit, and the active power to be absorbed proportionally according to the over-limit amount of the reverse transmission, the active power adjustment amount of each target charge and discharge unit is obtained. The active power setting value of the target charging and discharging unit is updated based on the active power adjustment amount of each target charging and discharging unit and the active power setting value of the target charging and discharging unit, so as to obtain the adjusted active power setting value of the target charging and discharging unit.

5. The method as described in claim 4, characterized in that, Before obtaining the active power adjustment amount of each target charge / discharge unit by proportionally allocating the active power to be absorbed based on the current adjustable target charge / discharge unit's adjustment margin, the weight of each charge / discharge unit, and the reverse transmission excess, the method further includes: Obtain the maximum active power and active power setting value of each charging and discharging unit; Based on the maximum active power capacity and active power setting value of the charging and discharging unit, the adjustment margin of each charging and discharging unit is determined, and the charging and discharging unit with an adjustment margin greater than the preset power threshold is taken as the target charging and discharging unit that can be adjusted up.

6. The method as described in claim 1, characterized in that, The V2G charging station also includes a local testing device, and the method further includes: When communication between the station side and the main trunk side and the feeder side is abnormal, the local measured voltage of the charging gun access point of each charging and discharging unit is obtained by the local measured device. The two-stage power logic operates based on local voltage. The active power setting value of each charging and discharging unit is determined according to the local measured voltage at the charging gun access point of each charging and discharging unit and the preset upper and lower limits of the node voltage, voltage threshold, slope coefficient and maximum charging capacity. Based on the logic of maintaining reactive power droop, the reactive power setting value of each charging and discharging unit is determined according to the local measured voltage, active power setting value, and preset maximum allowable apparent power, reactive power droop coefficient, and reference voltage of the charging gun access point of each charging and discharging unit, so that each charging and discharging unit of the V2G charging station operates based on the active and reactive power setting values ​​corresponding to the current time period.

7. The method as described in claim 6, characterized in that, The active power setting value of the charging and discharging unit is determined by the following formula: In the formula, For the first time in the current control cycle The active power command value of each charging and discharging unit; For the first The reference active power value for each charging and discharging unit; For the first Maximum charging power of each charging / discharging unit; For the first Locally measured voltage at the charging gun connection point of each charging / discharging unit; For the first The upper voltage threshold of each charge / discharge unit; For the first The voltage threshold of each charge / discharge unit; , These are the upper and lower limits of the allowable node voltage, respectively; This is the active power-voltage slope coefficient for the high voltage section. This represents the active power-voltage slope coefficient in the low voltage section.

8. A station-level control system for a V2G charging station based on reverse power flow suppression, characterized in that, The system includes: The data acquisition unit is used to acquire the power flow operation constraints and electricity price constraints of the backbone side, as well as the sensitivity parameters and power feedback upper limit of the feeder side, when the communication between the backbone side, the feeder side and the station side is normal. The sensitivity parameters are the sensitivity coefficients of the node voltage to the active and reactive power in the V2G charging station, and the node voltage is the voltage of the grid-connected node of the V2G charging station on the distribution feeder. The power prediction unit is used to prioritize reverse power flow suppression, dynamically unify the active and reactive power of each charging and discharging unit in the V2G charging station with the vehicle's SOC into a convex optimization problem, construct the in-station rolling optimization model of the V2G charging station, and calculate the set values ​​of active and reactive power of each charging and discharging unit in the next time period based on the power flow operation constraints, the electricity price constraints, sensitivity parameters, the upper limit of power back transmission, and the in-station rolling optimization model. The operation monitoring unit is used to monitor in real time whether the power backflow at the common coupling point exceeds the limit under the active / reactive power setpoints of each of the charging and discharging units in the current time period; when the power backflow at the common coupling point exceeds the limit, the backflow excess amount of the V2G charging station is obtained, and based on the fair weight and the backflow excess amount, absorption tasks are allocated among the currently adjustable target charging and discharging units, and the active power setpoints of the target charging and discharging units are adjusted so that each charging and discharging unit of the V2G charging station operates based on the adjusted active and reactive power setpoints corresponding to the current time period.

9. A computer-readable storage medium storing a computer program, characterized in that, When the computer program is executed by a processor, it causes the processor to perform the steps of the method as described in any one of claims 1 to 7.

10. A computer device, comprising a memory and a processor, characterized in that, The memory stores a computer program that, when executed by the processor, causes the processor to perform the steps of the method as described in any one of claims 1 to 7.

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