A direct-current bus type charging and discharging system energy collaborative regulation method based on CC-PFMS

Abstract

The present application belongs to the technical field of charge-discharge control, and in particular to a method for energy collaborative regulation of a DC bus type charge-discharge system based on CC-PFMS. The method comprises the following steps: S1: real-time detection and steady state determination of the DC bus based on CC-PFMS; S2: intelligent distribution of the grid side power of G2V and optimized scheduling of the user side V2G based on droop control and dynamic weight; S3: voltage emergency stabilization and collaborative regulation based on power balance. The present application significantly improves the stability of the DC bus voltage through moving average filtering and double threshold state determination; introduces dynamic monitoring and adaptive adjustment of circulating current indicators on the basis of droop control, effectively suppresses circulating current of multiple modules in parallel, and realizes balanced distribution of power; constructs a multi-factor scheduling model based on dynamic weight, taking into account the fairness of user demand and the economy of system operation; establishes an emergency working condition fast response mechanism based on the principle of capacitor energy storage balance, and realizes voltage fast recovery and power collaborative regulation.

Description

Technical Field

[0001] This invention relates to the field of charge and discharge control technology, specifically to a method for coordinated energy regulation of a DC bus-type charge and discharge system based on CC-PFMS. Background Technology

[0002] With the continuous expansion of new energy installed capacity and the explosive growth of electric vehicle ownership, large-scale DC charging infrastructure is showing a trend towards clustering and bus-based development. DC bus-type charging and discharging devices, through the parallel connection of multiple modules sharing a DC bus, can achieve flexible power allocation and multi-vehicle coordinated charging and discharging, significantly improving grid interaction capabilities and equipment utilization. However, its dynamic power allocation is essentially a high-dimensional, nonlinear, and multi-constraint costly multi-objective optimization problem: it requires simultaneously balancing multiple conflicting objectives such as charging efficiency, bus voltage stability, balanced module utilization, grid impact suppression, and user priority fairness. While traditional distributed power allocation strategies can achieve basic functions, they rely on independent decision-making based on local information, lack global coordination capabilities, are prone to circulating currents when multiple modules are connected in parallel, and exhibit lag in response to load changes or fault conditions, making them difficult to adapt to dynamic operating conditions. Summary of the Invention

[0003] The purpose of this section is to outline some aspects of the embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0004] To address the aforementioned technical problems, according to one aspect of the present invention, the present invention provides the following technical solution:

[0005] A method for coordinated energy regulation of a DC bus charging and discharging system based on CC-PFMS includes the following steps:

[0006] S1: First, a moving average filter is used to smooth the sampled voltage. The voltage deviation rate is calculated to determine the system's operating status. If the system is determined to be in normal operation, the normal power scheduling process S2 is entered based on the degree of voltage deviation. If a slight voltage deviation or a serious over-limit is detected, the emergency voltage regulation mechanism S3 is immediately triggered.

[0007] S2: Intelligent power allocation on the grid side and optimized V2G scheduling on the user side based on droop control and dynamic weighting;

[0008] S3: Emergency voltage stabilization and coordinated regulation based on power balance.

[0009] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the specific process of step S1 is as follows: multiple sampling points are set on the DC bus, and the voltage values ​​of each point are collected in real time at a high-frequency sampling rate. The smoothing preprocessing method is as follows:

[0010] (1)

[0011] In the formula, For the first Smoothed voltage values ​​at each sampling point For the first The measured voltage values ​​at each sampling point To determine the sliding window length, the window length selection must satisfy the following conditions:

[0012] (2)

[0013] In the formula, The filtering time constant is For the sampling period, take To balance filter performance with system dynamic response: A value that is too large will cause a slow response. If the value is too small, the filtering effect will be poor.

[0014] As a preferred embodiment of the energy coordinated control method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the specific method for judging the system operating status in step S1 is as follows: the voltage deviation rate is defined as the percentage deviation of the actual voltage relative to the reference voltage. :

[0015] (3)

[0016] In the formula, This is the smoothed DC bus voltage value. The reference voltage value set for the DC bus;

[0017] Dual threshold state determination is performed based on the degree of voltage deviation:

[0018] (4)

[0019] In the formula, This is the threshold for the normal state. This is the emergency threshold.

[0020] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, wherein S2.1: mode determination: by introducing a droop control strategy, automatic power distribution and circulating current suppression are achieved;

[0021] S2.2: G2V mode control: Based on the capacity weight of each module, the basic power command is allocated, and a negative gain voltage droop control loop is introduced to simulate the voltage-power characteristics of resistive load and determine the power allocation command of each AC / DC module.

[0022] S2.3: Vehicle-side dynamic weighted scheduling: A scheduling strategy based on dynamic weights is proposed, which comprehensively considers multiple factors such as battery state of charge, demand urgency, and user-defined priorities to achieve orderly charging and precise G2V scheduling.

[0023] S2.4: V2G Mode Control: Determines the vehicle's current SOC state and sets... Only vehicles that meet the discharge requirements can participate in the discharge. Then, the discharge priority weight is calculated, and the discharge power that each vehicle should output in V2G mode is calculated.

[0024] S2.5: Power Smoothing Switching: The target power command is low-pass filtered to obtain a smooth power command.

[0025] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the specific method of S2.1 is as follows: First, calculate the total power demand of the system in real time. :

[0026] (5)

[0027] in This refers to the total charge and discharge power of the battery. For the total system loss, according to The sign indicates that the current mode should be either G2V (grid charging the vehicle) or V2G (vehicle discharging to the grid). For G2V, It is V2G.

[0028] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the basic power command in S2.2... :

[0029] (6)

[0030] in, For the first Basic power commands for each AC / DC module For the first Rated power of each AC / DC module, This represents the total number of modules connected in parallel.

[0031] The method for simulating the voltage-power characteristics of a resistive load is as follows:

[0032] (7)

[0033] In the formula, For the first The droop adjustment power of each module For the first DC bus voltage measured by each AC / DC module The droop coefficient is the droop factor. The specific calculation formula is as follows:

[0034] (8)

[0035] In the formula, For the first The maximum allowable power adjustment for each AC / DC module is taken as the module's rated power. 10% to 30%; To determine the maximum allowable deviation of the DC bus voltage, take (±5% to 10%) of the reference voltage; the negative sign ensures the droop characteristic of reduced output power when the voltage increases.

[0036] Power allocation instructions for each AC / DC module :

[0037] (9)

[0038] To evaluate the effectiveness of droop control, the total circulating current of the system is calculated:

[0039] (10)

[0040] In the formula, This represents the effective value of the total circulating current of the system. For the first Each module outputs current. This represents the average output current of each module. This represents the total number of modules connected in parallel.

[0041] when At that time, the amplitude of the droop coefficient is adaptively increased. To enhance the inhibitory effect, among which This is the module's rated current.

[0042] As a preferred embodiment of the energy coordinated regulation method for a DC bus-type charging and discharging system based on CC-PFMS described in this invention, the specific method of S2.3 is as follows: First, dynamically calculate the charging priority weight of each electric vehicle in G2V mode. :

[0043] (11)

[0044] In the formula, For the first Charging priority of vehicles These are static weighting coefficients. A fixed priority level set for the user. This is the system's maximum priority value. For SOC weighting coefficients, For the first The vehicle's current state of charge. For the target state of charge, For time weighting coefficients, For the remaining charging time, The latest allowed completion time, where three coefficients are... And all items are normalized to interval;

[0045] Next, calculate the charging power that should be allocated to each vehicle in G2V mode. :

[0046] (12)

[0047] In the formula, For the first The charging power of the vehicle The total number of vehicles charging. The total available charging power is the maximum power that the system can allocate to all vehicles during the current period.

[0048] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, wherein the discharge priority weight in S2.4... The calculation method is as follows:

[0049] (13)

[0050] In the formula, For the first Discharge priority weight of the vehicle This refers to the static weighting coefficient for discharge. For static discharge priority, This is the discharge SOC weighting coefficient. This is the minimum safe discharge limit. At maximum state of charge, The weighting coefficient is the health status coefficient. For the first The higher the battery health status and discharge priority weight of a vehicle, the more suitable the vehicle is for participating in V2G.

[0051] Calculate the discharge power that each vehicle should output in V2G mode. :

[0052] (14)

[0053] In the formula, This represents the total number of vehicles capable of discharging electricity. This represents the absolute value of the total discharge power required by the power grid for the vehicle cluster at the current moment.

[0054] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the smooth power command in S2.5... The calculation method is as follows:

[0055] (15)

[0056] In the formula, These are the filter coefficients. The power is smoothed for the previous cycle. The original target power command;

[0057] At the same time, to limit the rate of power change, constraints are imposed on the amount of power change per unit time:

[0058] (16)

[0059] in, The maximum allowable power change rate needs to be adjusted according to the battery rate characteristics. To control the periodic sampling time.

[0060] As a preferred embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS described in this invention, the specific process of S3 is as follows:

[0061] When S1 detects an abnormal DC bus voltage, in order to quickly restore the voltage, it first calculates the power difference that needs to be adjusted based on the principle of DC bus capacitor energy storage balance. :

[0062] (17)

[0063] in, Adjust the power as needed. This represents the total equivalent capacitance of the DC bus. The desired voltage recovery time;

[0064] If detected If overvoltage occurs, overvoltage protection will be implemented. The specific protection measure is to proportionally and collaboratively reduce the charging power and the AC / DC side input power.

[0065] (18)

[0066] (19)

[0067] In the formula, This refers to the amount of power reduction during charging. This is the charging power reduction factor. This represents the amount of power reduction in the power grid. The power reduction factor of the power grid is determined by the following proportional allocation principle: ,and It should meet the following requirements:

[0068] (20)

[0069] In the formula, For the scalable charging power capacity, For the grid input capacity that can be reduced, if Forced , ;

[0070] If detected The specific protection measures are to proportionally and collaboratively reduce the discharge power and increase the input power on the AC / DC side:

[0071] (twenty one)

[0072] (twenty two)

[0073] In the formula, This is the amount of power reduction during discharge. This is the discharge power reduction factor. The power grid boosting factor is determined by the following proportional allocation principle: The coefficient selection rule is as follows: if the power grid supply capacity is sufficient, priority should be given to increasing the power grid supply; if the power grid is restricted or in a peak shaving and valley filling period, priority should be given to reducing the load.

[0074] Compared with existing technologies, the advantages of this invention are as follows: Based on a coordinated control and power flow management (CC-PFMS) energy coordination regulation strategy, this invention significantly improves DC bus voltage stability through moving average filtering and dual-threshold state determination; it introduces dynamic monitoring and adaptive adjustment of circulating current indicators on the basis of droop control, effectively suppressing multi-module parallel circulating current and achieving balanced power distribution; it constructs a multi-factor scheduling model based on dynamic weights, balancing user demand fairness with system operating economy; and it establishes a rapid response mechanism for emergency conditions based on the principle of capacitor energy storage balance, achieving rapid voltage recovery and coordinated power regulation. This invention, with its hierarchical and coordinated control architecture, solves key problems in existing technologies such as insufficient circulating current suppression, delayed response, and multi-objective conflicts, significantly improving the stability, balance, and dynamic adaptability of system operation, providing a systematic solution for the efficient and reliable operation of DC bus charging and discharging systems. Attached Figure Description

[0075] To more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and detailed embodiments. 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. Wherein:

[0076] Figure 1 This is a flowchart of an energy coordinated control method for a DC bus charging and discharging system based on CC-PFMS according to the present invention;

[0077] Figure 2 This is a comparison diagram of real-time DC bus voltage detection in an embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS of the present invention.

[0078] Figure 3 This is a comparison chart of voltage deviation percentage and stability determination in an embodiment of the energy coordinated control method for a DC bus charging and discharging system based on CC-PFMS of the present invention.

[0079] Figure 4 This is a comparison diagram of the voltage emergency regulation response effect in an embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS of the present invention;

[0080] Figure 5 This is a comparison diagram of the system power balance equation verification in an embodiment of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS of the present invention.

[0081] Figure 6This is a SOC optimization scheduling diagram based on CC-PFMS in an embodiment of the energy coordinated regulation method for a DC bus charging and discharging system according to the present invention. Detailed Implementation

[0082] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0083] Secondly, the present invention is described in detail with reference to the schematic diagrams. When detailing the embodiments of the present invention, for ease of explanation, the cross-sectional views illustrating the device structure may be partially enlarged, not according to the usual scale. Furthermore, the schematic diagrams are merely examples and should not limit the scope of protection of the present invention. In addition, actual fabrication should include three-dimensional spatial dimensions of length, width, and depth.

[0084] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0085] A method for coordinated energy regulation of a DC bus charging and discharging system based on CC-PFMS includes the following steps:

[0086] S1: Real-time DC bus monitoring and stability assessment based on CC-PFMS:

[0087] Multiple sampling points are set on the DC bus to acquire the voltage values ​​at each point in real time at a high-frequency sampling rate. To eliminate the impact of interference such as switching noise from the power electronic converter on control decisions, a moving average filter is first used to smooth the sampled voltages.

[0088] (1)

[0089] In the formula, For the first Smoothed voltage values ​​at each sampling point For the first The measured voltage values ​​at each sampling point To determine the sliding window length, the window length selection must satisfy the following conditions:

[0090] (2)

[0091] In the formula, The filtering time constant is For the sampling period, take To balance filter performance with system dynamic response: A value that is too large will cause a slow response. If the value is too small, the filtering effect will be poor.

[0092] Based on the smoothed voltage value, the voltage offset rate is calculated to determine the system's operating status. The voltage offset rate is defined as the percentage deviation of the actual voltage from the reference voltage. :

[0093] (3)

[0094] In the formula, This is the smoothed DC bus voltage value. The reference voltage value set for the DC bus.

[0095] Dual threshold state determination is performed based on the degree of voltage deviation:

[0096] (4)

[0097] In the formula, This is the threshold for the normal state. This is the emergency threshold. Based on the degree of voltage deviation, if the system is determined to be in normal operation, it enters the normal power scheduling process (S2); if a slight voltage deviation or a serious over-limit is detected, the emergency voltage regulation mechanism is immediately triggered (S3).

[0098] S2: Intelligent power allocation on the grid side and optimized V2G scheduling on the user side based on droop control and dynamic weighting:

[0099] S2.1: Pattern Determination:

[0100] In DC bus-type charging and discharging systems, when multiple grid-connected converters operate in parallel, circulating current problems are easily generated due to differences in component characteristics and control loop delays. Circulating current not only increases additional losses but can also cause individual modules to overload. This step introduces a droop control strategy to achieve automatic power sharing and circulating current suppression.

[0101] First, calculate the total power requirement of the system in real time. :

[0102] (5)

[0103] in This represents the total charge and discharge power of the battery (charge is positive, discharge is negative). For the total system loss, according to The symbol indicates that the current mode should be either G2V (grid charging vehicle) or V2G (vehicle discharging to grid). For G2V, (For V2G).

[0104] S2.2: G2V mode control:

[0105] First, the base power command is allocated according to the capacity weight of each module. :

[0106] (6)

[0107] in, For the first Basic power commands for each AC / DC module For the first Rated power of each AC / DC module, This represents the total number of modules connected in parallel. This pre-allocation method based on capacity ratio ensures that each module operates within a safe range and avoids overload.

[0108] However, simply allocating power according to capacity is insufficient to eliminate circulating current because there are slight differences in the actual bus voltage values ​​detected by each module. Therefore, a negative gain voltage droop control circuit is introduced to simulate the voltage-power characteristics of a resistive load, allowing the module output power to automatically fine-tune according to local voltage measurements.

[0109] (7)

[0110] In the formula, For the first The droop adjustment power of each module For the first DC bus voltage measured by each AC / DC module The droop coefficient is the droop factor. The specific calculation formula is as follows:

[0111] (8)

[0112] In the formula, For the first The maximum allowable power adjustment for an AC / DC module is typically taken as the module's rated power. 10% to 30%; To determine the maximum allowable deviation of the DC bus voltage, it is typically taken as ±(5% to 10%) of the reference voltage; the negative sign ensures the droop characteristic of reduced output power when the voltage increases.

[0113] Finally, the power allocation instructions for each AC / DC module are determined. :

[0114] (9)

[0115] To evaluate the effectiveness of droop control, the total circulating current of the system is calculated:

[0116] (10)

[0117] In the formula, This represents the effective value of the total circulating current of the system. For the first Each module outputs current. This represents the average output current of each module. This represents the total number of modules connected in parallel. The effectiveness of circulating current suppression can be quantitatively evaluated by monitoring the amplitude of the circulating current in real time.

[0118] when At that time, the amplitude of the droop coefficient is adaptively increased. To enhance the inhibitory effect, among which This is the module's rated current.

[0119] S2.3: Vehicle-side dynamic weight scheduling:

[0120] When a charging station serves multiple electric vehicles simultaneously, the charging and discharging power of the vehicles needs to be optimized and scheduled. To address this, a scheduling strategy based on dynamic weights is proposed, which comprehensively considers multiple factors such as battery state of charge (SOC), demand urgency, and user-defined priorities to achieve orderly charging and precise G2V scheduling.

[0121] First, the charging priority weight of each electric vehicle in G2V mode is dynamically calculated. :

[0122] (11)

[0123] In the formula, For the first Charging priority of vehicles This is a static weighting coefficient (representing the user-defined priority percentage). A fixed priority level set for the user. This is the system's maximum priority value. This is the SOC weighting coefficient (representing the proportion of urgency in electricity demand). For the first The vehicle's current state of charge (0-100%). For the target state of charge, This is the time weighting coefficient (representing the proportion of time urgency). For the remaining charging time, This represents the latest allowed completion time. The three coefficients are... And all items are normalized to Interval.

[0124] Next, calculate the charging power that should be allocated to each vehicle in G2V mode. :

[0125] (12)

[0126] In the formula, For the first The charging power of the vehicle The total number of vehicles charging. The total available charging power is the maximum power that the system can allocate to all vehicles during the current period.

[0127] S2.4: V2G mode control:

[0128] For V2G mode, the first step is to determine the vehicle's current SOC state, which is usually set as follows: Only vehicles meeting the discharge criteria are allowed to participate in the discharge process. Subsequently, their discharge priority weights are calculated. :

[0129] (13)

[0130] In the formula, For the first Discharge priority weight of the vehicle This refers to the static weighting coefficient for discharge. For static discharge priority, This is the discharge SOC weighting coefficient. This is the minimum safe discharge limit (usually set at 20%). This represents the maximum state of charge (usually set to 90%). The weighting coefficient is the health status coefficient. For the first The vehicle's battery health status (0-1). The higher the discharge priority weight, the more suitable the vehicle is for V2G participation.

[0131] Next, calculate the discharge power that each vehicle should output in V2G mode. :

[0132] (14)

[0133] In the formula, This represents the total number of vehicles capable of discharging electricity. This represents the absolute value of the total discharge power required by the power grid for the vehicle cluster at the current moment.

[0134] S2.5: Smooth power switching:

[0135] Sudden changes in power command can impact batteries and the power grid, shortening battery life and affecting grid stability. To avoid this problem, the target power command needs to be low-pass filtered to obtain a smooth power command. :

[0136] (15)

[0137] In the formula, These are the filter coefficients. The power is smoothed for the previous cycle. This is the original target power command.

[0138] At the same time, to limit the rate of power change, constraints are imposed on the amount of power change per unit time:

[0139] (16)

[0140] in, The maximum allowable power change rate needs to be adjusted according to the battery rate characteristics. To control the periodic sampling time.

[0141] S3: Emergency voltage stabilization and coordinated regulation based on power balance:

[0142] When S1 detects an abnormal DC bus voltage, in order to quickly restore the voltage, it first calculates the power difference that needs to be adjusted based on the principle of DC bus capacitor energy storage balance. :

[0143] (17)

[0144] in, The required power adjustment amount (positive value indicates that power needs to be added, negative value indicates that power needs to be reduced). This represents the total equivalent capacitance of the DC bus. This represents the desired voltage recovery time.

[0145] If detected If overvoltage occurs, overvoltage protection will be activated. Common causes of overvoltage include: sudden drop in load power, unexpected interruption of the charging process, and concentrated discharge of multiple vehicles in V2G mode. Specific protection measures include proportionally and collaboratively reducing the charging power and AC / DC side input power.

[0146] (18)

[0147] (19)

[0148] In the formula, This refers to the amount of power reduction during charging. This is the charging power reduction factor. This represents the amount of power reduction in the power grid. This represents the power reduction factor for the power grid. The proportional allocation principle is as follows: ,and It should meet the following requirements:

[0149] (20)

[0150] In the formula, For the scalable charging power capacity, This refers to the grid input capacity that can be reduced. Typically, charging power is reduced first. This is because the charging response is faster and has less impact on the user. (Severe overpressure), forced , (Charging only).

[0151] If detected If undervoltage occurs, undervoltage protection will be activated. Common causes of undervoltage include: a sudden decrease in output from distributed power sources such as photovoltaics, a sudden increase in charging load, and insufficient grid power supply. Specific protection measures involve proportionally reducing discharge power and increasing AC / DC input power.

[0152] (twenty one)

[0153] (twenty two)

[0154] In the formula, This is the amount of power reduction during discharge. This is the discharge power reduction factor. This is the power grid boosting factor. The proportional allocation principle is as follows: The coefficient selection rule is as follows: if the power grid supply capacity is sufficient (capacity margin > 30%), priority should be given to increasing the power grid supply. If the power grid is constrained (capacity margin <10%) or during peak shaving and valley filling periods, priority should be given to reducing load. ).

[0155] Example:

[0156] To verify the effectiveness of the proposed method, the proposed CC-PFMS strategy was compared with the traditional decentralized power allocation (TDPA) strategy through simulations on the MATLAB / Simulink platform. The flowchart of the energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS is shown below. Figure 1 As shown in Table 1, the parameters of the control system used in the MATLAB / Simulink digital simulation are listed.

[0157] Table 1 Simulation Model Parameters

[0158]

[0159] To simulate the real working environment of a DC bus-type charging and discharging device, the constraints are set as follows:

[0160] (1) DC bus voltage fluctuation ≤ ±5% ;

[0161] (2) The power distribution imbalance of the AC / DC modules is ≤10%;

[0162] (3) The power grid power change rate is ≤50 kW / s to ensure no impact;

[0163] (4) When electric vehicles participate in V2G discharge, the SOC must be higher than 30%.

[0164] Figure 2 The image shows a comparison of real-time DC bus voltage monitoring, illustrating the voltage waveforms under CC-PFMS and TDPA strategies. CC-PFMS, through smoothing filtering and stability determination, reduces the voltage standard deviation from 70.12V in TDPA to 9.41V, an improvement of 86.6%, while the voltage consistently closely follows the reference value.

[0165] Figure 3 The chart shows a comparison between the percentage of voltage deviation and stability assessment. CC-PFMS increased the percentage of time the voltage deviation was stable within ±2% from 28.4% in TDPA to 96.7%, significantly enhancing system stability.

[0166] Figure 4 The graph shows a comparison of the voltage emergency regulation response. When the voltage is abnormal, CC-PFMS, based on power balance fast response, reduces the over-threshold time from 71.6% of TDPA to 3.3%, and the maximum deviation from 112.5V to 47.3V, with a response improvement of 95.4%.

[0167] Figure 5 The comparison diagram for verifying the system power balance equation shows that the capacitor power fluctuation is smoother under CC-PFMS, and the power conservation relationship is accurately satisfied.

[0168] Figure 6 The SOC optimization scheduling graph based on CC-PFMS uses dynamic weight allocation to maintain a balance of SOC for each vehicle during charging and discharging, thus avoiding overcharging or over-discharging of some batteries.

[0169] Simulation tests were conducted under four scenarios: normal operation (G2V charging), V2G discharging, power surge, and voltage emergency. It can be seen that, in all scenarios, the CC-PFMS strategy outperforms the TDPA strategy in terms of voltage stability, power distribution balance, and emergency response speed. Specifically, CC-PFMS can control voltage deviation within ±2%, reduce AC / DC module power imbalance to below 5%, shorten voltage recovery time by approximately 50% in emergency situations, and achieve balanced and reasonable SOC management.

[0170] Although the present invention has been described above with reference to embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, as long as there is no structural conflict, the features in the disclosed embodiments can be combined with each other in any manner. The lack of an exhaustive description of these combinations in this specification is merely for the sake of brevity and resource conservation. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A method for energy collaborative regulation of a CC-PFMS-based direct-current bus type charge-discharge system, characterized in that, Includes the following steps: S1: The sampled voltage is smoothed by using a moving average filter, and the voltage deviation rate is calculated to determine the system operating status. If the system is determined to be in normal operation, the normal power scheduling process S2 is entered based on the degree of voltage deviation. If a slight voltage deviation or a serious over-limit is detected, the emergency voltage regulation mechanism S3 is triggered. S2: Intelligent power allocation on the grid side and optimized V2G scheduling on the user side based on droop control and dynamic weighting: S2.1: Mode determination: By introducing a droop control strategy, automatic power sharing and circulating current suppression are achieved; S2.2: G2V mode control: Based on the capacity weight of each module, the basic power command is allocated, and a negative gain voltage droop control loop is introduced to simulate the voltage-power characteristics of resistive load and determine the power allocation command of each AC / DC module. S2.3: Vehicle-side dynamic weighted scheduling: A scheduling strategy based on dynamic weights is proposed, which comprehensively considers multiple factors such as battery state of charge, demand urgency, and user-defined priorities to achieve orderly charging and precise G2V scheduling. S2.4: V2G mode control: determine the current SOC state of the vehicles, set vehicles can participate in discharging, then, calculate the discharge priority weight of each vehicle, and calculate the discharge power that each vehicle should output in V2G mode; S2.5: Power Smoothing Switching: The target power command is low-pass filtered to obtain a smooth power command; The base power instruction in S2.2 : wherein, is the base power command for the th AC / DC module, is the rated power of the th AC / DC module, is the total number of parallel modules; The method for simulating the voltage-power characteristics of a resistive load is as follows: In the formula, For the first The droop adjustment power of each module For the first DC bus voltage measured by each AC / DC module The reference voltage value set for the DC bus. The droop coefficient is the droop factor. The specific calculation formula is as follows: In the formula, For the first The maximum allowable power adjustment for each AC / DC module is taken as the module's rated power. 10% to 30%; To determine the maximum allowable deviation of the DC bus voltage, take ±(5%~10%) of the reference voltage; the negative sign ensures the droop characteristic of reduced output power when the voltage increases. Power allocation instructions for each AC / DC module : To evaluate the effectiveness of droop control, the total circulating current of the system is calculated: In the formula, This represents the effective value of the total circulating current of the system. For the first Each module outputs current. This represents the average output current of each module. This represents the total number of modules connected in parallel. when At that time, the amplitude of the droop coefficient is adaptively increased. To enhance the inhibitory effect, among which This is the module's rated current. S3: Emergency voltage stabilization and coordinated regulation based on power balance: The specific process is as follows: When S1 detects an abnormal DC bus voltage, in order to quickly restore the voltage, it first calculates the power difference that needs to be adjusted based on the principle of DC bus capacitor energy storage balance. : in, Adjust the power as required. This represents the total equivalent capacitance of the DC bus. For the desired voltage recovery time, The reference voltage value set for the DC bus; If detected If overvoltage occurs, overvoltage protection will be implemented. The specific protection measure is to proportionally and collaboratively reduce the charging power and the AC / DC side input power. In the formula, This refers to the amount of power reduction during charging. This is the charging power reduction factor. This represents the amount of power reduction in the power grid. The power reduction factor of the power grid is determined by the following proportional allocation principle: ,and It should meet the following requirements: In the formula, For the scalable charging power capacity, For the grid input capacity that can be reduced, if Forced , ; If detected The specific protection measures are to proportionally and synergistically reduce the discharge power and increase the input power on the AC / DC side: In the formula, This is the amount of power reduction during discharge. This is the discharge power reduction factor. The power grid boosting factor is determined by the following proportional allocation principle: The coefficient selection rule is as follows: if the power grid supply capacity is sufficient, priority should be given to increasing the power grid supply; if the power grid is restricted or in a peak shaving and valley filling period, priority should be given to reducing the load.

2. The energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS according to claim 1, characterized in that, The specific process of S1 is as follows: multiple sampling points are set on the DC bus, and the voltage values ​​of each point are collected in real time at a high frequency sampling rate. The smoothing preprocessing method is as follows: In the formula, For the first Smoothed voltage values ​​at each sampling point For the first The measured voltage values ​​at each sampling point To determine the sliding window length, the window length selection must satisfy the following conditions: In the formula, The filtering time constant is For the sampling period, take To balance filter performance with system dynamic response: A value that is too large will cause a slow response. If the value is too small, the filtering effect will be poor.

3. The energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS according to claim 1, characterized in that, The specific method for judging the system operating status in S1 is as follows: the voltage offset rate is defined as the percentage deviation of the actual voltage relative to the reference voltage. : In the formula, This is the smoothed DC bus voltage value. The reference voltage value set for the DC bus; Dual threshold state determination is performed based on the degree of voltage deviation: In the formula, This is the threshold for the normal state. This is the emergency threshold.

4. The energy coordinated regulation method for a DC bus-based charging and discharging system based on CC-PFMS according to claim 1, characterized in that, The specific method of S2.1 is as follows: First, calculate the total power demand of the system in real time. : in This refers to the total charge and discharge power of the battery. For the total system loss, according to The sign indicates that the current mode should be either G2V (grid charging the vehicle) or V2G (vehicle discharging to the grid). For G2V, It is V2G.

5. The energy coordinated regulation method for a DC bus-type charging and discharging system based on CC-PFMS according to claim 1, characterized in that, The specific method of S2.3 is as follows: First, dynamically calculate the charging priority weight of each electric vehicle in G2V mode. : In the formula, For the first Charging priority of vehicles These are static weighting coefficients. A fixed priority level set for the user. This is the system's maximum priority value. For SOC weighting coefficients, For the first The vehicle's current state of charge. For the target state of charge, For time weighting coefficients, For the remaining charging time, The latest allowed completion time, where three coefficients are... And all items are normalized to interval; Next, calculate the charging power that should be allocated to each vehicle in G2V mode. : In the formula, For the first The charging power of the vehicle The total number of vehicles charging. The total available charging power is the maximum power that the system can allocate to all vehicles during the current period.

6. The energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS according to claim 1, characterized in that, Discharge priority weight in S2.4 The calculation method is as follows: In the formula, For the first Discharge priority weight of the vehicle This refers to the static weighting coefficient for discharge. For static discharge priority, This is the discharge SOC weighting coefficient. This is the minimum safe limit for discharge. At maximum state of charge, The weighting coefficient is the health status coefficient. For the first The higher the battery health status and discharge priority weight of a vehicle, the more suitable the vehicle is for participating in V2G. Calculate the discharge power that each vehicle should output in V2G mode. : In the formula, This represents the total number of vehicles capable of discharging electricity. This represents the absolute value of the total discharge power required by the power grid for the vehicle cluster at the current moment.

7. The energy coordinated regulation method for a DC bus charging and discharging system based on CC-PFMS according to claim 1, characterized in that, Smooth power command in S2.5 The calculation method is as follows: In the formula, These are the filter coefficients. The power is smoothed for the previous cycle. The original target power command; At the same time, to limit the rate of power change, constraints are imposed on the amount of power change per unit time: in, The maximum allowable power change rate needs to be adjusted according to the battery rate characteristics. To control the periodic sampling time.

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