Hybrid energy storage power distribution method and system based on charge-discharge margin dynamic evaluation
Patent Information
- Application Number
- CN202611128141.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-28
- Publication Date
- 2026-10-27
AI Technical Summary
就目前而言，现有储能功率分配方法多采用固定截止频率滤波，无法随运行状态自适应调整频带，易致功率型储能容量饱和
本发明通过耦合电化学、热及电压约束构建连续充放电裕度，并自适应驱动频域分解截止频率，实现了频率响应与实时承载能力的高效匹配。并且，本发明结合预测越限后的跨单元功率平移补偿与爬坡约束，在彻底消除越限保护风险的同时保证了功率平稳输出，显著提升了系统的动态响应质量并延长了储能寿命。
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Figure CN122992919A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of power system technology, and more specifically, to a hybrid energy storage power allocation method and system based on dynamic assessment of charge and discharge margin. Background Technology
[0002] With the high proportion of new energy sources integrated into the new power system, hybrid energy storage systems composed of power-type and energy-type energy storage have become an important support for regulation. Power-type energy storage has a fast response but limited capacity, while energy-type energy storage has a large capacity but a slower response. Deconstructing real-time power commands and allocating them to the two types of energy storage, allowing each to leverage its respective advantages, is key to ensuring efficient system operation. Currently, existing energy storage power allocation methods mostly use fixed cutoff frequency filtering, which cannot adaptively adjust the frequency band according to operating conditions, easily leading to capacity saturation of power-type energy storage. At the same time, existing methods mainly rely on static state of charge segmentation, ignoring the dynamic constraints of voltage, temperature, and internal resistance on transient power limits, and lacking a coordinated mechanism of frequency domain decomposition and time domain margin, which easily triggers over-limit protection and accelerates battery degradation. Summary of the Invention
[0003] The purpose of this invention is to provide a hybrid energy storage power allocation method and system based on dynamic evaluation of charge and discharge margin. It completely eliminates the risk of power exceeding limits by adaptively driving frequency domain decomposition and cross-cell power compensation based on charge and discharge margin, thus ensuring the stable and efficient operation of hybrid energy storage.
[0004] This invention is achieved through the following technical solution: A hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin includes: Obtain the total power command of the target hybrid energy storage system for the current cycle, as well as the operating status parameters of the power-type energy storage unit and the energy-type energy storage unit; Construct the continuous dynamic charge / discharge margin function of the power-type energy storage unit and the energy-type energy storage unit at the current moment; The cutoff frequency of the frequency domain decomposition is adaptively solved based on the dynamic charge and discharge margin of the power-type energy storage unit, and the total power command is decomposed into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency. The high-frequency dynamic power component and the low-frequency baseline power component are mapped to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial power allocation. The initial power allocation is used to predict the margin of the two types of energy storage units at the next time step. When the predicted margin exceeds the preset safety threshold, cross-unit power shift compensation is performed to output the final power allocation.
[0005] Optionally, constructing the continuous dynamic charge / discharge margin function of the power-type energy storage unit and the energy-type energy storage unit at the current moment includes: Obtain the state of charge, terminal voltage, real-time temperature, and dynamic internal resistance from the operating status parameters; The capacity margin is obtained by calculating the difference between the state of charge and the preset upper and lower safety boundaries. By combining the terminal voltage, real-time temperature, and dynamic internal resistance, the maximum permissible continuous charge and discharge power without triggering voltage protection under the current state is calculated, and the transient power margin is obtained. By weighted coupling of the capacity margin and transient power margin, the charging margin and discharging margin of the power-type energy storage unit and the charging margin and discharging margin of the energy-type energy storage unit are obtained, respectively.
[0006] Optionally, the capacity margin and transient power margin are weighted and coupled, including: Acquire the real-time health status and internal temperature gradient of the power-type energy storage unit and the energy-type energy storage unit; Calculate the capacity decay correction factor based on the health status and the power limitation correction factor based on the temperature gradient; Based on the capacity attenuation correction coefficient and the power limitation correction coefficient, the weighting of the capacity margin and the transient power margin is dynamically adjusted; The capacity margin and transient power margin are linearly weighted and summed according to the adjusted weighting to generate a continuous charge-discharge margin.
[0007] Optionally, the cutoff frequency of the frequency domain decomposition is adaptively solved based on the dynamic charge-discharge margin of the power-type energy storage unit, including: Determine the charging and discharging direction of the current total power command; The charging margin or discharging margin corresponding to the power-type energy storage unit is extracted by the charging and discharging direction. Construct a monotonically positive correlation mapping function between the cutoff frequency and the charge margin or discharge margin; The real-time cutoff frequency is calculated using the mapping function, wherein when the margin decreases, the cutoff frequency is adaptively lowered to shrink the frequency band response range of the power storage unit.
[0008] Optionally, calculating the real-time cutoff frequency using the mapping function further includes: Calculate the absolute value of the difference between the real-time cutoff frequency obtained in the current control cycle and the cutoff frequency that took effect in the previous control cycle; Determine whether the absolute value of the difference is less than a preset frequency dead zone threshold; When the absolute value of the difference is less than the preset frequency dead zone threshold, the cutoff frequency of the previous control cycle remains unchanged. When the absolute value of the difference is greater than or equal to the preset frequency dead zone threshold, the current real-time cutoff frequency is smoothed using a moving average window, and the filtered value is updated to the cutoff frequency that is effective in the current control cycle.
[0009] Optionally, the total power command is decomposed into a high-frequency dynamic power component and a low-frequency baseline power component according to the cutoff frequency, including: A dynamic variable parameter low-pass filter is constructed based on the cutoff frequency; The total power command is input into the dynamic variable parameter low-pass filter, and the low-frequency baseline power component is output. The high-frequency dynamic power component is obtained by subtracting the total power command from the low-frequency baseline power component.
[0010] Optionally, the high-frequency dynamic power component and the low-frequency baseline power component are mapped to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial power allocation, including: The high-frequency dynamic power component is used as the initial power allocation for the power-type energy storage unit; The low-frequency baseline power component is used as the initial power allocation for the energy storage unit.
[0011] Optionally, the next-time margin of the two types of energy storage units is predicted using the initial allocated power, and cross-unit power shift compensation is performed when the predicted margin exceeds a preset safety threshold, outputting the final allocated power, including: Based on the initial power allocation, the predicted state of charge and predicted terminal voltage for the next control cycle are calculated using the electrochemical models of the two types of energy storage units. The predicted charge / discharge margin is updated based on the predicted state of charge and predicted terminal voltage. When the predicted charge / discharge margin of the power storage unit is lower than a preset safety threshold, the over-limit power exceeding the safety threshold is calculated. The over-limit power is superimposed on the initial allocated power of the energy storage unit through a first-order rate of change limiter to generate the final allocated power of the energy storage unit. The initial allocated power is subtracted from the over-limit power to generate the final allocated power of the power-type energy storage unit.
[0012] Optionally, the excess power is superimposed onto the initial allocated power of the energy storage unit through a first-order rate-of-change limiter to generate the final allocated power of the energy storage unit, including: Obtain the preset maximum allowable power ramp rate of the energy storage unit; Divide the over-limit power by the duration of a single control cycle to calculate the rate of change of the over-limit power; When the rate of change of the over-limit power is greater than the maximum allowable power ramp rate, the rate of change of the over-limit power is truncated and constrained to the maximum allowable power ramp rate. The rate of change after the truncation constraint is accumulated frame by frame according to the control cycle to generate a smoothly changing power compensation amount, and the power compensation amount is superimposed on the initial allocated power of the energy storage unit.
[0013] A hybrid energy storage power allocation system based on dynamic assessment of charge / discharge margin includes: The data acquisition module is used to obtain the total power command of the target hybrid energy storage system in the current cycle, as well as the operating status parameters of the power-type energy storage unit and the energy-type energy storage unit; The margin assessment module is used to construct the continuous dynamic charge and discharge margin function of the power-type energy storage unit and the energy-type energy storage unit at the current moment; An adaptive decomposition module is used to adaptively solve the cutoff frequency of the frequency domain decomposition based on the dynamic charge and discharge margin of the power-type energy storage unit, and decompose the total power command into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency. The initial mapping module is used to map the high-frequency dynamic power component and the low-frequency baseline power component to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial allocated power. The compensation control module is used to predict the margin of the two types of energy storage units in the next moment based on the initial allocation power, and to perform cross-unit power shift compensation when the predicted margin exceeds the preset safety threshold, and output the final allocation power.
[0014] The technical solution of the present invention has at least the following advantages and beneficial effects: This invention constructs a continuous charge-discharge margin by coupling electrochemical, thermal, and voltage constraints, and adaptively drives the frequency domain decomposition cutoff frequency, achieving efficient matching between frequency response and real-time load capacity. Furthermore, by combining predicted cross-cell power shift compensation and ramp-up constraints after exceeding limits, this invention completely eliminates the risk of exceeding limits while ensuring stable power output, significantly improving the system's dynamic response quality and extending energy storage life. Attached Figure Description
[0015] Figure 1 A flowchart of the hybrid energy storage power allocation method based on dynamic evaluation of charge-discharge margin provided by the present invention; Figure 2 The schematic diagram of the hybrid energy storage power distribution system based on dynamic evaluation of charge and discharge margin provided by the present invention. Detailed Implementation
[0016] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.
[0017] Example 1 The first embodiment of this invention relates to a hybrid energy storage power allocation method based on dynamic assessment of charge-discharge margin, such as... Figure 1 As shown, this embodiment specifically includes the following steps: Step 101: Obtain the total power command of the target hybrid energy storage system for the current cycle, as well as the operating status parameters of the power-type energy storage unit and the energy-type energy storage unit.
[0018] Specifically, in control scenarios where hybrid energy storage systems are connected to the grid for secondary frequency regulation, smoothing power fluctuations from new energy sources, or participating in microgrid energy management, the energy management system or grid dispatch center issues a total power command for the current control cycle according to a fixed sampling period. The hybrid energy storage system comprises power-type energy storage units and energy-type energy storage units. The power-type energy storage units utilize flywheel energy storage or supercapacitors, while the energy-type energy storage units utilize lithium iron phosphate battery packs or sodium-ion battery packs.
[0019] The data acquisition equipment collects the operating status parameters of the two types of energy storage units in real time via fieldbus. The collected operating status parameters include the real-time state of charge, terminal voltage, real-time temperature, and dynamic internal resistance of each type of energy storage unit.
[0020] Step 102: Based on the operating state parameters, construct the continuous dynamic charge and discharge margin functions for the power-type energy storage unit and the energy-type energy storage unit at the current moment.
[0021] Specifically, the continuous dynamic charge-discharge margin function is used to quantitatively characterize the physical potential of an energy storage unit to absorb or release power under the current electrochemical and thermal conditions. Based on the collected state of charge, terminal voltage, real-time temperature, and dynamic internal resistance, the capacity margin and transient power margin are calculated. The capacity margin reflects the remaining energy storage and release space of the energy storage unit in the time domain, while the transient power margin reflects the maximum allowable power of the energy storage unit without triggering hardware overvoltage or undervoltage protection. By weighted coupling of the capacity margin and transient power margin, the charge margin and discharge margin of power-type energy storage units and energy-type energy storage units are derived, respectively.
[0022] Step 103: Based on the dynamic charge and discharge margin of the power-type energy storage unit, adaptively solve the cutoff frequency of the frequency domain decomposition, and decompose the total power command into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency.
[0023] Specifically, the traditional method of fixing the low-pass filter cutoff frequency can cause power-type energy storage units to continue receiving high-frequency, high-power commands even when their capacity is close to saturation, leading to overcharging or over-discharging. This embodiment adaptively adjusts the filter cutoff frequency based on the real-time dynamic charge / discharge margin of the power-type energy storage unit. First, the sign of the current total power command is determined to ascertain the charge / discharge direction, and the real-time margin of the power-type energy storage unit in that direction is extracted. The real-time cutoff frequency is then calculated based on the monotonically positive correlation between the cutoff frequency and the margin. When the margin of the power-type energy storage unit decreases, the cutoff frequency is adaptively lowered, reducing the passband width of the low-pass filter, blocking or attenuating more high-frequency components, and narrowing the frequency response range of the power-type energy storage unit. A variable-parameter low-pass filter is constructed using the real-time cutoff frequency to filter the total power command, obtaining the low-frequency baseline power component. Subtracting the low-frequency baseline power component from the total power command yields the high-frequency dynamic power component.
[0024] Step 104: Map the high-frequency dynamic power component and the low-frequency baseline power component to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial power allocation.
[0025] Specifically, based on the physical characteristics of power-type energy storage units responding to high-frequency rapid response requirements and energy-type energy storage units bearing low-frequency stable energy requirements, the high-frequency dynamic power component is directly assigned as the initial allocated power of the power-type energy storage unit, and the low-frequency baseline power component is directly assigned as the initial allocated power of the energy-type energy storage unit.
[0026] Step 105: Based on the initial allocated power, predict the margin of the two types of energy storage units at the next time step, and when the predicted margin exceeds the preset safety threshold, perform cross-unit power shift compensation and output the final allocated power.
[0027] Specifically, to avoid physical limits being exceeded in the next control cycle due to filtering delays or sudden high-power surges, this embodiment introduces a predictive compensation mechanism before the actual power is distributed. Based on the initial allocated power of the two types of energy storage units and their equivalent circuit physical models, the predicted state of charge and predicted terminal voltage for the next control cycle are calculated, thereby updating the predicted charge / discharge margin. When the predicted charge / discharge margin of the power-type energy storage unit is lower than a preset safety threshold, it indicates that the power-type energy storage unit will experience capacity or voltage limits exceeding the threshold in the next cycle, and the excess power exceeding the safety threshold is calculated. The excess power is superimposed on the initial allocated power of the energy-type energy storage unit through a first-order rate of change limiter to generate the final allocated power of the energy-type energy storage unit; simultaneously, the excess power is subtracted from the initial allocated power of the power-type energy storage unit to generate the final allocated power of the power-type energy storage unit. The final allocated power is converted into control pulses and sent to the corresponding power converter to complete the power allocation and output for the current control cycle.
[0028] Through steps 101 to 105 above, this embodiment realizes a complete control logic that uses electrochemical and thermal states to drive frequency domain decomposition and then uses prediction margin closed-loop feedback to perform cross-unit power compensation, eliminating the technical defect of frequency domain decomposition and time domain safety boundary being disconnected in traditional allocation strategies.
[0029] Example 2 The second embodiment of the present invention relates to a hybrid energy storage power allocation method based on dynamic evaluation of charge-discharge margin. This embodiment is a supplement to step 102 in the first embodiment mentioned above, and specifically describes the construction process of the continuous dynamic charge-discharge margin function.
[0030] In this embodiment, the steps for constructing the continuous dynamic charge-discharge margin function specifically include: The system acquires the state of charge (SOC), terminal voltage, real-time temperature, and dynamic internal resistance from the operating parameters. The SOC is estimated using a fusion of the ampere-hour integral method and the unscented Kalman filter algorithm; the terminal voltage and real-time temperature are directly acquired from the hardware sensors of the battery management system; and the dynamic internal resistance is updated in real time using offline table lookup and online recursive least squares method.
[0031] The capacity margin is obtained by calculating the difference between the state of charge and the preset upper and lower safety boundaries. The calculation of the capacity margin is specifically divided into charging capacity margin and discharging capacity margin.
[0032] The calculation logic for charging capacity margin is as follows: The difference between the upper limit safe state of charge and the current state of charge is then divided by the difference between the upper limit safe state of charge and the lower limit safe state of charge.
[0033] The calculation logic for discharge capacity margin is as follows: The difference between the current state of charge and the lower limit of the safe state of charge is then divided by the difference between the upper limit of the safe state of charge and the lower limit of the safe state of charge. Under a specific setting, the upper limit of the safe state of charge is 95%, and the lower limit of the safe state of charge is 5%. This results in both the charging capacity margin and the discharging capacity margin being normalized to the range of zero to one.
[0034] By combining terminal voltage, real-time temperature and dynamic internal resistance, the maximum allowable continuous charge and discharge power that does not trigger voltage protection under the current state is calculated, and the transient power margin is obtained.
[0035] The calculation logic for transient power margin during charging is as follows: Based on the current real-time temperature and terminal voltage, the maximum allowable cut-off charging voltage is obtained. The difference between the maximum allowable cut-off charging voltage and the current terminal voltage is used to obtain the maximum allowable voltage compensation. The maximum allowable voltage compensation is divided by the dynamic internal resistance to obtain the maximum allowable charging current. The maximum allowable charging current is multiplied by the current terminal voltage to obtain the transient maximum allowable charging power. The transient maximum allowable charging power is divided by the rated charge / discharge power of the power-type energy storage unit or the energy-type energy storage unit to obtain the normalized charging transient power margin.
[0036] The transient power margin under discharge conditions is calculated as follows: The difference between the front-end voltage and the preset minimum allowable cut-off discharge voltage is used to obtain the discharge voltage buffer. Dividing the discharge voltage buffer by the dynamic internal resistance yields the maximum allowable discharge current. Multiplying the maximum allowable discharge current by the current front-end voltage yields the maximum allowable transient discharge power. Dividing the maximum allowable transient discharge power by the rated charge / discharge power yields the normalized discharge transient power margin.
[0037] By weighted coupling of capacity margin and transient power margin, the charging margin and discharging margin of power-type energy storage units and the charging margin and discharging margin of energy-type energy storage units are obtained, respectively.
[0038] Specifically, the computational logic for weighted coupling is as follows: Real-time charging margin equals the product of charging capacity margin and the first weight, plus the product of charging transient power margin and the second weight; real-time discharging margin equals the product of discharging capacity margin and the first weight, plus the product of discharging transient power margin and the second weight. The sum of the first and second weights equals one. Initially, both the first and second weights are set to 0.5.
[0039] This embodiment integrates the time-domain capacity state with the electrochemical transient voltage limit into a unified scalar margin index, which accurately reflects the real-time carrying capacity potential of the energy storage unit under different operating conditions.
[0040] Example 3 The third embodiment of the present invention relates to a hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin. This embodiment is a supplement to step 103 in the previous embodiment, and specifically explains the solution and filtering decomposition process of the cutoff frequency.
[0041] This embodiment specifically includes the following steps: Determine the charging / discharging direction of the current total power command. When the total power command is greater than zero, the system is determined to be in charging mode; when the total power command is less than zero, the system is determined to be in discharging mode; when the total power command is equal to zero, maintain the allocation state of the previous control cycle.
[0042] Based on the charging and discharging direction, extract the charging margin or discharging margin corresponding to the power-type energy storage unit. When the system is determined to be in charging condition, extract the charging margin of the power-type energy storage unit; when the system is determined to be in discharging condition, extract the discharging margin of the power-type energy storage unit.
[0043] A monotonically positive correlation mapping function between cutoff frequency and charge margin or discharge margin is constructed. In a specific implementation scenario, the mapping function is constructed using a piecewise S-curve or exponential curve. Its basic physical constraint is that the cutoff frequency must be limited between a preset lower cutoff frequency and an upper cutoff frequency. The lower cutoff frequency is set based on the maximum allowable response bandwidth of the energy-type energy storage unit, and its value is 0.001 Hz; the upper cutoff frequency is set based on the upper limit of the optimal response frequency band of the power-type energy storage unit, and its value is 0.1 Hz.
[0044] The calculation logic of the mapping function is as follows: The real-time cutoff frequency equals the lower cutoff frequency, plus the difference between the upper and lower cutoff frequencies, multiplied by the nonlinear function value of the normalized margin. The nonlinear function form of the normalized margin is a converted combination of the cube of the normalized margin and the square of the normalized margin. When the extracted margin is close to one, indicating extremely abundant capacity and power, the real-time cutoff frequency approaches the upper cutoff frequency; when the extracted margin is close to zero, indicating that capacity or power is approaching saturation, the real-time cutoff frequency adaptively decreases, approaching the lower cutoff frequency.
[0045] A dynamically variable parameter low-pass filter is constructed based on the real-time cutoff frequency. The low-pass filter is implemented using a first-order discrete Butterworth low-pass filter or a first-order inertial element. The discretized transfer function coefficients of the filter are dynamically updated according to the real-time cutoff frequency calculated in each control cycle. The total power command is input to the dynamically variable parameter low-pass filter, and the filter output is the low-frequency baseline power component.
[0046] The high-frequency dynamic power component is obtained by subtracting the total power command from the low-frequency baseline power component. The high-frequency dynamic power component includes the rapid fluctuations in the total power command above the real-time cutoff frequency, while the low-frequency baseline power component includes the gradual changes below the real-time cutoff frequency.
[0047] Based on this embodiment, the cutoff frequency of the low-pass filter is no longer a fixed value, but dynamically shifts with the real-time carrying capacity of the power storage unit, realizing real-time coordination between frequency domain decomposition and time domain state.
[0048] Example 4 The fourth embodiment of the present invention relates to a hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin. This embodiment is a further optimization of the aforementioned second embodiment, specifically introducing health status and temperature gradient to dynamically correct the weighting weights.
[0049] This embodiment specifically includes the following steps: The real-time health status and internal temperature gradient of the two types of energy storage units are acquired. The real-time health status is obtained by cross-estimation of cumulative ampere-hour throughput and electrochemical impedance spectroscopy, and is expressed as the ratio of the current maximum available capacity to the initial rated capacity. The internal temperature gradient is obtained by collecting data from multiple temperature sensors distributed at different locations in the energy storage cell array, and the temperature difference between the highest and lowest temperature points is calculated.
[0050] The capacity decay correction factor is calculated based on the health status, and the power limitation correction factor is calculated based on the temperature gradient.
[0051] The calculation logic for the capacity decay correction factor is as follows: When the health status is greater than 90%, the capacity decay correction factor is set to a value of 1; when the health status is less than or equal to 90%, the capacity decay correction factor decreases linearly as the health status decreases, and the calculation formula is the current health status divided by 90%.
[0052] The calculation logic for the power limitation correction factor is as follows: When the internal temperature gradient of the enclosure is less than the preset temperature gradient safety threshold of five degrees Celsius, the power limit correction factor is set to a value of one; when the temperature gradient is greater than or equal to five degrees Celsius, the power limit correction factor is calculated using an exponential decay function, and decreases rapidly as the temperature gradient increases.
[0053] The weighting of capacity margin and transient power margin is dynamically adjusted based on the capacity decay correction factor and the power limitation correction factor.
[0054] Specifically, the dynamic adjustment logic for the first weight is as follows: The initial first weight is multiplied by the capacity decay correction factor, and then divided by the weighted sum of the capacity decay correction factor and the power limitation correction factor.
[0055] The dynamic adjustment logic for the second weight is as follows: The initial second weight is multiplied by the power limitation correction factor, and then divided by the weighted sum of the capacity attenuation correction factor and the power limitation correction factor. The adjusted first and second weights are automatically normalized.
[0056] The capacity margin and transient power margin are linearly weighted and summed according to the adjusted weighting to generate a continuous charge-discharge margin.
[0057] When an energy storage unit experiences severe aging, i.e., a significant decline in its health, the system automatically increases the weight of capacity margin to prioritize ensuring that remaining capacity does not exceed limits. When there is internal thermal imbalance in the energy storage system, i.e., a large temperature gradient, the system automatically increases the weight of transient power margin to forcibly constrain transient power output and prevent the spread of thermal runaway. This embodiment significantly improves the adaptability of margin assessment to aging and thermal safety evolution throughout the entire life cycle.
[0058] Example 5 The fifth embodiment of the present invention relates to a hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin. This embodiment is a refinement of the smoothing and vibration suppression process after calculating the real-time cutoff frequency in the third embodiment mentioned above.
[0059] In the actual operation of a hybrid energy storage system, drastic fluctuations in total power command or sensor noise can cause high-frequency jitter in the calculated real-time cutoff frequency, leading to frequent oscillations in the coefficients of the variable-parameter low-pass filter and resulting in non-physical power output fluctuations. To eliminate this phenomenon, this embodiment further performs the following processing steps after solving for the real-time cutoff frequency: Calculate the absolute value of the difference between the real-time cutoff frequency obtained in the current control cycle and the cutoff frequency that took effect in the previous control cycle.
[0060] Determine whether the absolute value of the difference is less than a preset frequency dead zone threshold. In a specific setting, the preset frequency dead zone threshold is two percent of the difference between the upper cutoff frequency and the lower cutoff frequency.
[0061] When the absolute value of the difference is less than the preset frequency dead zone threshold, it is determined that the current slight change in margin belongs to sensor noise or harmless disturbance, and the cutoff frequency of the previous control cycle remains unchanged. That is, the cutoff frequency effective in the current control cycle is directly assigned to the cutoff frequency effective in the previous control cycle.
[0062] When the absolute value of the difference is greater than or equal to the preset frequency dead zone threshold, the decision margin has changed substantially, and smoothing filtering is initiated. A moving average window is used to smooth the current real-time cutoff frequency. The length of the moving average window is set to five to ten control cycles. The value calculated by the moving average is updated to the cutoff frequency effective in the current control cycle and used for reconstructing the transfer function coefficients of the subsequent low-pass filter.
[0063] This embodiment eliminates frequent oscillations of the cutoff frequency in the critical range, ensuring a smooth transition of filter parameters and guaranteeing the continuity and stability of power commands sent to the power converter.
[0064] Example 6 The sixth embodiment of the present invention relates to a hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin. This embodiment is a supplement to step 105 in the first embodiment mentioned above, and specifically describes the cross-cell power translation compensation and ramping constraint logic based on the predicted margin.
[0065] In this embodiment, the steps for performing cross-unit power shift compensation and outputting the final allocated power specifically include: Based on the initial power allocation and combined with the electrochemical models of the two types of energy storage units, the predicted state of charge and predicted terminal voltage for the next control cycle are calculated.
[0066] Specifically, the electrochemical model employs a second-order RC equivalent circuit model, including an open-circuit voltage source, an ohmic internal resistance, and two pairs of parallel RC circuits. The predicted state of charge (SOC) for the next control cycle is calculated by integrating the current over time. Substituting the predicted SOC into the open-circuit voltage mapping curve yields the predicted open-circuit voltage. Using the state-space equations of the second-order RC equivalent circuit, combined with the capacitive polarization voltage of the current cycle, the predicted polarization voltage for the next control cycle is solved. The predicted terminal voltage is equal to the algebraic sum of the predicted open-circuit voltage, the predicted polarization voltage, and the predicted ohmic voltage drop.
[0067] Based on the predicted state of charge and predicted terminal voltage, the predicted charge and discharge margins of the two types of energy storage units in the next control cycle are updated according to the margin calculation method in the second embodiment described above.
[0068] When the predicted charge / discharge margin of a power-type energy storage unit is lower than a preset safety threshold, it is determined that the power-type energy storage unit will exceed the limit in the next cycle. The preset safety threshold is set to 0.1. The power exceeding the safety threshold is calculated. The power exceeding the limit is calculated as follows: the difference between the preset safety threshold and the predicted charge / discharge margin, multiplied by the rated power of the power-type energy storage unit, and then divided by the safety threshold itself.
[0069] Obtain the preset maximum allowable power ramp rate for the energy storage unit. The maximum allowable power ramp rate is determined by the battery chemistry of the energy storage unit and is set to 5% of the rated power per second. Divide the over-limit power by the duration of a single control cycle to calculate the rate of change of the over-limit power.
[0070] When the rate of change of the over-limit power is greater than the maximum allowable power ramp rate, the rate of change of the over-limit power is truncated and constrained to the maximum allowable power ramp rate; when the rate of change of the over-limit power is less than or equal to the maximum allowable power ramp rate, the rate of change of the over-limit power remains unchanged.
[0071] The rate of change after truncation constraint is accumulated frame by frame according to the control period to generate a smoothly changing power compensation amount.
[0072] The power compensation is superimposed on the initial allocated power of the energy storage unit to generate the final allocated power of the energy storage unit.
[0073] The final allocated power of the power-type energy storage unit is generated by subtracting this power compensation amount from the initial allocated power of the power-type energy storage unit.
[0074] Through the cross-unit power translation compensation mechanism in this embodiment, when the power-type energy storage unit is about to exceed the safety boundary, the part exceeding its carrying capacity is dynamically translated to the energy-type energy storage unit. At the same time, the energy-type energy storage unit is protected from high-frequency impact by the ramp rate cutoff, thus achieving seamless connection of the safety boundaries of the two types of energy storage units.
[0075] Example 7 The seventh embodiment of the present invention relates to a hybrid energy storage power allocation system based on dynamic assessment of charge-discharge margin, such as... Figure 2 As shown, this embodiment is used to execute the hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin as described in any of the first to sixth embodiments above.
[0076] The hybrid energy storage power distribution system in this embodiment includes: a data acquisition module, a margin assessment module, an adaptive decomposition module, an initial mapping module, and a compensation control module.
[0077] The data acquisition module is used to obtain the total power command of the target hybrid energy storage system in the current cycle, as well as the real-time operating status parameters of the power-type energy storage unit and the energy-type energy storage unit.
[0078] The margin assessment module is used to construct continuous dynamic charge / discharge margin functions for power-type and energy-type energy storage units at the current moment, based on real-time operating status parameters. The margin assessment module internally includes a capacity margin calculation unit, a transient power margin calculation unit, and a weight dynamic correction unit.
[0079] The adaptive decomposition module is used to adaptively solve for the cutoff frequency in the frequency domain based on the dynamic charge / discharge margin of the power storage unit, and decompose the total power command into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency. The adaptive decomposition module internally includes a direction determination unit, a cutoff frequency mapping unit, a dead-zone smoothing unit, and a variable-parameter low-pass filter unit.
[0080] The initial mapping module is used to map the high-frequency dynamic power component and the low-frequency baseline power component to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial allocated power.
[0081] The compensation control module is used to predict the next-time margin of the two types of energy storage units based on the initial allocated power, and to perform cross-unit power shift compensation when the predicted margin exceeds a preset safety threshold, outputting the final allocated power. The compensation control module internally includes a state prediction unit, an over-limit power solution unit, a first-order rate of change limiting unit, and a power superposition output unit.
[0082] This embodiment achieves closed-loop operation of real-time data acquisition, processing, margin calculation, adaptive filtering, and predictive compensation through the coordinated cooperation between various modules, ensuring the efficient implementation of the control method.
[0083] Example 8 The eighth embodiment of the present invention relates to an electronic device, as shown in the figure, including at least one processor and a memory communicatively connected to the at least one processor.
[0084] The memory stores computer instructions that can be executed by at least one processor. When executed by at least one processor, the computer instructions enable at least one processor to perform the hybrid energy storage power allocation method based on dynamic assessment of charge-discharge margin as described in any of the first to sixth embodiments.
[0085] The memory and processor are connected via an internal bus. This bus can include any number of interconnect buses and bus bridges, connecting various circuits of the processor and memory. The bus can also connect peripheral devices, voltage regulators, and power management circuits. The memory can be various non-volatile or volatile storage media, such as read-only memory, random access memory, disk storage, or flash memory. The processor can be a general-purpose central processing unit, a microprocessor, a digital signal processor, or an application-specific integrated circuit (ASIC).
[0086] Example 9 The ninth embodiment of the present invention relates to a computer-readable storage medium having a computer program stored thereon.
[0087] When the computer program is executed by the processor, it implements the hybrid energy storage power allocation method based on dynamic evaluation of charge and discharge margin as described in any of the first to sixth embodiments.
[0088] Computer-readable storage media include various physical media that can store program code, such as flash drives, portable hard drives, read-only memory, random access memory, magnetic disks, or optical disks.
[0089] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.
Claims
1. A hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin, characterized in that, include: Obtain the total power command of the target hybrid energy storage system for the current cycle, as well as the operating status parameters of the power-type energy storage unit and the energy-type energy storage unit; Construct the continuous dynamic charge / discharge margin function of the power-type energy storage unit and the energy-type energy storage unit at the current moment; The cutoff frequency of the frequency domain decomposition is adaptively solved based on the dynamic charge and discharge margin of the power-type energy storage unit, and the total power command is decomposed into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency. The high-frequency dynamic power component and the low-frequency baseline power component are mapped to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial power allocation. The initial power allocation is used to predict the margin of the two types of energy storage units at the next time step. When the predicted margin exceeds the preset safety threshold, cross-unit power shift compensation is performed to output the final power allocation.
2. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 1, characterized in that, Constructing the continuous dynamic charge / discharge margin functions of the power-type energy storage unit and the energy-type energy storage unit at the current moment includes: Obtain the state of charge, terminal voltage, real-time temperature, and dynamic internal resistance from the operating status parameters; The capacity margin is obtained by calculating the difference between the state of charge and the preset upper and lower safety boundaries. By combining the terminal voltage, real-time temperature, and dynamic internal resistance, the maximum permissible continuous charge and discharge power without triggering voltage protection under the current state is calculated, and the transient power margin is obtained. By weighted coupling of the capacity margin and transient power margin, the charging margin and discharging margin of the power-type energy storage unit and the charging margin and discharging margin of the energy-type energy storage unit are obtained, respectively.
3. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 2, characterized in that, Weighted coupling of the capacity margin and transient power margin includes: Acquire the real-time health status and internal temperature gradient of the power-type energy storage unit and the energy-type energy storage unit; Calculate the capacity decay correction factor based on the health status and the power limitation correction factor based on the temperature gradient; Based on the capacity attenuation correction coefficient and the power limitation correction coefficient, the weighting of the capacity margin and the transient power margin is dynamically adjusted; The capacity margin and transient power margin are linearly weighted and summed according to the adjusted weighting to generate a continuous charge-discharge margin.
4. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 3, characterized in that, The cutoff frequency of the frequency domain decomposition is adaptively solved based on the dynamic charge-discharge margin of the power-type energy storage unit, including: Determine the charging and discharging direction of the current total power command; The charging margin or discharging margin corresponding to the power-type energy storage unit is extracted by the charging and discharging direction. Construct a monotonically positive correlation mapping function between the cutoff frequency and the charge margin or discharge margin; The real-time cutoff frequency is calculated using the mapping function, wherein when the margin decreases, the cutoff frequency is adaptively lowered to shrink the frequency band response range of the power storage unit.
5. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 4, characterized in that, Calculating the real-time cutoff frequency using the mapping function further includes: Calculate the absolute value of the difference between the real-time cutoff frequency obtained in the current control cycle and the cutoff frequency that took effect in the previous control cycle; Determine whether the absolute value of the difference is less than a preset frequency dead zone threshold; When the absolute value of the difference is less than the preset frequency dead zone threshold, the cutoff frequency of the previous control cycle remains unchanged. When the absolute value of the difference is greater than or equal to the preset frequency dead zone threshold, the current real-time cutoff frequency is smoothed using a moving average window, and the filtered value is updated to the cutoff frequency that is effective in the current control cycle.
6. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 5, characterized in that, The total power command is decomposed into a high-frequency dynamic power component and a low-frequency baseline power component based on the cutoff frequency, including: A dynamic variable parameter low-pass filter is constructed based on the cutoff frequency; The total power command is input into the dynamic variable parameter low-pass filter, and the low-frequency baseline power component is output. The high-frequency dynamic power component is obtained by subtracting the total power command from the low-frequency baseline power component.
7. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 6, characterized in that, Mapping the high-frequency dynamic power component and the low-frequency baseline power component to the power-type energy storage unit and the energy-type energy storage unit respectively to generate the initial power allocation includes: The high-frequency dynamic power component is used as the initial power allocation for the power-type energy storage unit; The low-frequency baseline power component is used as the initial power allocation for the energy storage unit.
8. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 7, characterized in that, The initial allocated power is used to predict the next-time margin of the two types of energy storage units, and when the predicted margin exceeds a preset safety threshold, cross-unit power shift compensation is performed to output the final allocated power, including: Based on the initial power allocation, the predicted state of charge and predicted terminal voltage for the next control cycle are calculated using the electrochemical models of the two types of energy storage units. The predicted charge / discharge margin is updated based on the predicted state of charge and predicted terminal voltage. When the predicted charge / discharge margin of the power storage unit is lower than a preset safety threshold, the over-limit power exceeding the safety threshold is calculated. The over-limit power is superimposed on the initial allocated power of the energy storage unit through a first-order rate of change limiter to generate the final allocated power of the energy storage unit. The initial allocated power is subtracted from the over-limit power to generate the final allocated power of the power-type energy storage unit.
9. The hybrid energy storage power allocation method based on dynamic assessment of charge / discharge margin according to claim 8, characterized in that, The excess power is superimposed onto the initial allocated power of the energy storage unit through a first-order rate-of-change limiter to generate the final allocated power of the energy storage unit, including: Obtain the preset maximum allowable power ramp rate of the energy storage unit; Divide the over-limit power by the duration of a single control cycle to calculate the rate of change of the over-limit power; When the rate of change of the over-limit power is greater than the maximum allowable power ramp rate, the rate of change of the over-limit power is truncated and constrained to the maximum allowable power ramp rate. The rate of change after the truncation constraint is accumulated frame by frame according to the control cycle to generate a smoothly changing power compensation amount, and the power compensation amount is superimposed on the initial allocated power of the energy storage unit.
10. A hybrid energy storage power allocation system based on dynamic assessment of charge / discharge margin, characterized in that, include: The data acquisition module is used to obtain the total power command of the target hybrid energy storage system in the current cycle, as well as the operating status parameters of the power-type energy storage unit and the energy-type energy storage unit; The margin assessment module is used to construct the continuous dynamic charge and discharge margin function of the power-type energy storage unit and the energy-type energy storage unit at the current moment; An adaptive decomposition module is used to adaptively solve the cutoff frequency of the frequency domain decomposition based on the dynamic charge and discharge margin of the power-type energy storage unit, and decompose the total power command into high-frequency dynamic power components and low-frequency baseline power components according to the cutoff frequency. The initial mapping module is used to map the high-frequency dynamic power component and the low-frequency baseline power component to the power-type energy storage unit and the energy-type energy storage unit, respectively, to generate the initial allocated power. The compensation control module is used to predict the margin of the two types of energy storage units at the next moment based on the initial allocation power, and to perform cross-unit power shift compensation when the predicted margin exceeds the preset safety threshold, and output the final allocation power.