Power distribution method and system for photovoltaic off-grid

Abstract

The invention relates to the technical field of energy management, in particular to a power distribution method and system for photovoltaic off-grid. According to the method, the input power of the photovoltaic module is dynamically acquired, and the instantaneous change rate calculation mode is combined, so that the photovoltaic power trend is accurately judged, and unstable power distribution caused by power fluctuation is avoided. According to the change of the photovoltaic power level, instantaneous demand analysis is carried out on the off-grid power supply equipment, and fine classification is carried out according to the voltage adaptation range and the operation mode, so that various types of equipment can obtain more reasonable power distribution. Based on a load classification result, power supply deviation calculation is combined, the power supply priority of each type of equipment is dynamically adjusted, the power supply stability of key equipment is ensured, and meanwhile the operation efficiency of adjustable equipment is improved. In combination with a power supply distribution strategy of a multi-stage direct-current bus, an optimal bus is adaptively matched according to equipment voltage, and a connection mode is dynamically adjusted, so that bus power supply is more balanced, and the condition of insufficient power supply or overload is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of energy management, and particularly to a power distribution method and system for photovoltaic off-grid power supply. Background Art

[0002] The technical field of energy management includes various technical methods for optimizing the management of energy production, transmission, storage, and utilization. The core contents of this technical field include aspects such as energy supply and demand scheduling, power quality management, coordinated control of energy storage systems, and optimization of distributed energy systems. Specifically, energy management involves real-time monitoring of the grid operation status, load forecasting, energy storage control, and scheduling optimization, etc., to improve energy utilization efficiency, reduce energy consumption, and achieve efficient utilization of renewable energy.

[0003] Among them, the power distribution method and system for photovoltaic off-grid power supply refer to a photovoltaic power generation system that operates independently of the public grid, including output power management of photovoltaic modules, charge and discharge control of storage batteries, and power distribution mechanisms on the load side. It adopts a dynamic adjustment method based on voltage, current, and power detection to coordinate the energy flow between photovoltaic power generation units, energy storage units, and electrical equipment.

[0004] During the operation of the photovoltaic off-grid power supply method, the unreasonable energy distribution is often caused by the instability of photovoltaic power, affecting the continuity of equipment operation. Due to the lack of fine analysis of the change trend of photovoltaic power, the system is difficult to effectively respond to instantaneous power fluctuations, resulting in power supply shortages when sudden load increases occur. In terms of load management, existing methods often adopt fixed-priority scheduling and cannot flexibly adjust the power supply order of equipment. When the power supply deviation is large, some key equipment may still be affected. In addition, there is a problem of rigid connection in the bus power supply distribution mechanism. The power supply method of equipment is fixed and cannot be dynamically adjusted according to the bus load condition, resulting in some buses being overloaded while some buses have redundant power supply, reducing the overall power supply balance. The management method of energy storage equipment is relatively single and fails to optimize the charge and discharge strategy in combination with the change trend of photovoltaic power. When the photovoltaic power fluctuates violently, it is difficult to provide an effective compensation effect, affecting the operation reliability of the system in low-irradiance environments. Due to the lack of a dynamic adjustment mechanism for the power demand of equipment and the matching error of power supply, some equipment may be in an inefficient operation state for a long time, resulting in a decrease in energy utilization efficiency. Summary of the Invention

[0005] The purpose of the present invention is to solve the disadvantages existing in the prior art, and to propose a power distribution method and system for photovoltaic off-grid power supply.

[0006] To achieve the above purpose, the present invention adopts the following technical scheme: A power distribution method for photovoltaic off-grid power supply, including the following steps:

[0007] S1: Obtain the input power of the photovoltaic module, calculate the instantaneous change rate, judge the change trend of the photovoltaic power, record the current photovoltaic power level, and obtain the photovoltaic power change information;

[0008] S2: Analyze the photovoltaic power level based on the photovoltaic power change information, obtain the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and obtain the load power classification result;

[0009] S3: Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and obtain the photovoltaic power supply adjustment result;

[0010] S4: Based on the photovoltaic power supply adjustment result, connect the equipment to the DC bus of the corresponding voltage, calculate the total power demand of each type of DC bus and compare it with the available power of the current bus, adjust the power supply connection method of the equipment, and obtain the hierarchical bus power supply distribution information;

[0011] S5: Obtain the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjust the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result.

[0012] The improvements of the present invention are that the photovoltaic power change information includes the photovoltaic power change trend category, the photovoltaic power fluctuation amplitude, and the current photovoltaic power level. The load power classification result includes the priority power supply equipment category, the intermittently operable equipment category, and the equipment category that can be turned off when the photovoltaic power is insufficient. The photovoltaic power supply adjustment result includes the power supply priority of each type of equipment, the maximum allowable power of the adjustable load, and the optimal load reduction power of the non-critical load. The hierarchical bus power supply distribution information includes the total power demand of the voltage bus, the available power of the current bus, the bus power supply deviation, and the adjusted power supply connection method of the equipment. The photovoltaic off-grid power distribution result includes the power supply power of the critical load, the charge and discharge plan of the energy storage device, and the dynamic adjustment of the photovoltaic input power.

[0013] The improvements of the present invention are that the specific steps of obtaining the input power of the photovoltaic module, calculating the instantaneous change rate, judging the change trend of the photovoltaic power, and recording the current photovoltaic power level to obtain the photovoltaic power change information are as follows:

[0014] S101: Obtain the input power, voltage value and current value of the photovoltaic module, set a fixed time interval to record the power data, screen out abnormal power points, calculate the power change value between adjacent time points and record the time stamp to obtain the photovoltaic power sequence;

[0015] S102: Select data at consecutive time points from the photovoltaic power sequence, set a calculation window to take the average of the change rates at multiple consecutive moments, calculate the derivative of power with respect to time, obtain the power change rate within a specified time, record the direction of the power change trend, and obtain the photovoltaic input power change rate.

[0016] S103: Based on the photovoltaic input power change rate, set a photovoltaic power fluctuation threshold, compare the current change rate with the fluctuation threshold. If the change rate exceeds the fluctuation threshold, mark the photovoltaic power as being in an upward or downward trend according to the change direction. If it does not exceed the fluctuation threshold, mark it as a stable trend, and at the same time record the current photovoltaic power level to obtain the photovoltaic power change information.

[0017] The improvement of the present invention is as follows. Based on the photovoltaic power change information, analyze the photovoltaic power level, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and the specific steps for obtaining the load power classification result are as follows:

[0018] S201: Obtain the current photovoltaic power level from the photovoltaic power change information, calculate the power change rate, divide the power fluctuation amplitude into intervals, set a photovoltaic power level classification threshold, compare the current power level with the classification threshold, and determine whether the photovoltaic power is in a sufficient, critical, or insufficient state to obtain the photovoltaic power level state.

[0019] S202: Based on the photovoltaic power level state, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment, set an operating mode classification standard, determine whether the equipment is in continuous operation, intermittent operation, or standby mode, and record the characteristic parameters of each equipment to obtain the power supply equipment characteristic data.

[0020] S203: Based on the power supply equipment characteristic data, calculate the power demand of the equipment under each operating mode according to the photovoltaic power level state, screen the priority power supply equipment, intermittently operable equipment, and equipment that can be turned off when the photovoltaic power is insufficient, set the power supply priority of the equipment, and obtain the load power classification result.

[0021] The improvement of the present invention is as follows. Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and the specific steps for obtaining the photovoltaic power supply adjustment result are as follows:

[0022] S301: Based on the load power classification result, obtain the instantaneous power demand of the priority power supply equipment, intermittently operable equipment, and equipment that can be turned off when the photovoltaic power is insufficient, calculate the total power demand of each type of equipment, and obtain the total power demand of the classified equipment.

[0023] S302: Based on the total power demand of the classification device, obtain the current photovoltaic power level, calculate the power supply deviation between the photovoltaic power and the total power demand, set a power supply deviation threshold. If the deviation exceeds the deviation threshold, calculate the adjustable power according to the demand ratio of each category of device. If the deviation is within the deviation threshold range, keep the current power supply state unchanged to obtain the photovoltaic power matching result;

[0024] S303: Based on the photovoltaic power matching result, adjust the power distribution according to the power supply stability requirements of the priority power supply devices. If the power supply deviation is positive, increase the power supply of the intermittently operable devices. If the deviation is negative, reduce the power supply of the devices that can be turned off when the photovoltaic power is insufficient, and re - allocate the power supply order to obtain the photovoltaic power supply adjustment result.

[0025] The improvement of the present invention is as follows. Based on the photovoltaic power supply adjustment result, connect the devices to the DC busbars of the corresponding voltages, calculate the total power demand of each type of DC busbar and compare it with the available power of the current busbar, and adjust the power supply connection mode of the devices to obtain the hierarchical busbar power supply distribution information. The specific steps are as follows:

[0026] S401: Based on the photovoltaic power supply adjustment result, obtain the voltage adaptation range of each off - grid power supply device, screen the devices that meet the working requirements of multiple types of DC busbars, and match the buses that meet the operating requirements according to the rated working voltage of the devices and the rated voltage of each busbar, and preliminarily determine the power supply connection relationship of the devices to obtain the initial busbar access situation of the devices;

[0027] S402: Based on the initial busbar access situation of the devices, obtain the total power demand of the devices connected to each busbar, calculate the available power of the current busbar, set a busbar power supply threshold, calculate the power supply deviation of each busbar. If the deviation value exceeds the busbar power supply threshold, mark the busbar as being in a power supply shortage or overload state, and calculate the standby voltage corresponding to each device to obtain the busbar power supply analysis result;

[0028] S403: Based on the busbar power supply analysis result, screen the busbars with power supply shortage or overload, determine the list of devices that need to be adjusted. If a busbar is in an overload state, preferentially adjust the intermittently operable devices to the busbars with lower voltages. If the busbar has a power supply shortage, adjust some low - power devices to the busbars with higher voltages to keep the busbar power supply deviation within the busbar power supply threshold range to obtain the hierarchical busbar power supply distribution information.

[0029] The improvement of the present invention is as follows. Obtain the power supply state of each type of busbar from the hierarchical busbar power supply distribution information, and adjust the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off - grid power distribution result. The specific steps are as follows:

[0030] S501: Based on the hierarchical bus power supply distribution information, obtain the power supply status of each type of DC bus, calculate the current power supply of the bus, set a power matching error threshold according to the power demand of the photovoltaic energy storage power supply equipment, calculate the error value between the current power supply and the demand of the energy storage power supply equipment. If the error exceeds the error threshold, mark it as an abnormal power supply deviation state to obtain the power supply matching error analysis result;

[0031] S502: Based on the power supply matching error analysis result, calculate the current power supply capacity. If the power supply deviation is negative, reduce the power supply of the equipment that can be turned off when the photovoltaic power is insufficient, and adjust the power supply priority of the priority power supply equipment. If the power supply deviation is positive, increase the power supply of the equipment that can operate intermittently, and recalculate the matching error for the adjusted power supply data to obtain the critical load power supply adjustment value;

[0032] S503: Based on the critical load power supply adjustment value, analyze the change trend of the photovoltaic input power and the charge and discharge status of the current energy storage device, set an energy storage power adjustment threshold. If the photovoltaic power is on the rise, increase the charging power of the energy storage device. If it is on the decline, increase the discharge power of the energy storage device to maintain the stability of the bus power and obtain the photovoltaic off-grid power distribution result.

[0033] A power distribution system for photovoltaic off-grid, the system includes:

[0034] The photovoltaic power fluctuation detection module obtains the input power of the photovoltaic module and calculates the instantaneous change rate, judges the change trend of the photovoltaic power, and records the current photovoltaic power level to obtain the photovoltaic power change information;

[0035] The load characteristic analysis and classification module analyzes the photovoltaic power level based on the photovoltaic power change information, obtains the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply equipment, and classifies various types of power supply equipment to obtain the load power classification result;

[0036] The power supply priority adjustment module calculates the total power demand of each type of off-grid power supply equipment based on the load power classification result, adjusts the power supply priority of each type of electrical equipment to obtain the photovoltaic power supply adjustment result;

[0037] The hierarchical bus power supply management module connects the equipment to the DC bus of the corresponding voltage based on the photovoltaic power supply adjustment result, calculates the total power demand of each type of DC bus and compares it with the available power of the current bus, adjusts the power supply connection method of the equipment to obtain the hierarchical bus power supply distribution information;

[0038] The energy storage dynamic regulation module obtains the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjusts the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result.

[0039] Compared with the prior art, the advantages and positive effects of the present invention are as follows:

[0040] In the present invention, by dynamically obtaining the input power of the photovoltaic module and combining the instantaneous change rate calculation method, accurate judgment of the photovoltaic power trend is achieved, avoiding the unstable power distribution caused by power fluctuations. According to the change of the photovoltaic power level, instantaneous demand analysis is carried out on the off-grid power supply equipment, and fine classification is carried out according to the voltage adaptation range and operation mode, so that various equipment can obtain more reasonable power allocation. Based on the load classification results, combined with the power supply deviation calculation, the power supply priority of various equipment is dynamically adjusted to ensure the power supply stability of key equipment and improve the operation efficiency of adjustable equipment at the same time. Combining the power supply distribution strategy of the multi-level DC bus, the optimal bus is matched according to the equipment voltage adaptability, and the connection method is dynamically adjusted to make the bus power supply more balanced and reduce the situation of power supply shortage or overload. Relying on the trend analysis of the photovoltaic input power and combining the bus power supply status, the charging and discharging of the energy storage equipment are flexibly regulated. When the photovoltaic power rises, electric energy is preferentially stored, and when the power drops, it is reasonably released, improving the sustainability and stability of the overall power supply. By accurately calculating the power supply deviation and combining the dynamic adjustment of the equipment power demand matching error, the optimal allocation of power supply resources is achieved, avoiding energy waste and improving the overall energy efficiency of the photovoltaic off-grid system. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 is a flowchart of the present invention;

[0042] Figure 2 is a system module diagram of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0043] In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0044] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention. In addition, in the description of the present invention, "a plurality of" means two or more unless otherwise specifically defined.

[0045] Please refer to Figure 1, the present invention provides a technical solution: a power distribution method for photovoltaic off-grid, including the following steps:

[0046] S1: Obtain the input power of the photovoltaic module and calculate the instantaneous change rate, judge the change trend of the photovoltaic power, record the current photovoltaic power level, and obtain the photovoltaic power change information;

[0047] S2: Analyze the photovoltaic power level based on the photovoltaic power change information, obtain the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and obtain the load power classification result;

[0048] S3: Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and obtain the photovoltaic power supply adjustment result;

[0049] S4: Based on the photovoltaic power supply adjustment result, connect the equipment to the DC bus of the corresponding voltage, calculate the total power demand of each type of DC bus and compare it with the available power of the current bus, adjust the power supply connection method of the equipment, and obtain the hierarchical bus power supply distribution information;

[0050] S5: Obtain the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjust the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result.

[0051] The photovoltaic power change information includes the photovoltaic power change trend category, the photovoltaic power fluctuation amplitude, and the current photovoltaic power level. The load power classification result includes the priority power supply equipment category, the intermittently operable equipment category, and the equipment category that can be turned off when the photovoltaic power is insufficient. The photovoltaic power supply adjustment result includes the power supply priority of each type of equipment, the maximum allowable power of the adjustable load, and the optimal load reduction power of the non-critical load. The hierarchical bus power supply distribution information includes the total power demand of the voltage bus, the available power of the current bus, the bus power supply deviation, and the adjusted equipment power supply connection method. The photovoltaic off-grid power distribution result includes the power supply power of the critical load, the charge and discharge plan of the energy storage device, and the dynamic adjustment of the photovoltaic input power.

[0052] The specific steps to obtain the input power of the photovoltaic module and calculate the instantaneous change rate, judge the change trend of the photovoltaic power, and record the current photovoltaic power level to obtain the photovoltaic power change information are as follows:

[0053] S101: Obtain the input power, voltage value and current value of the photovoltaic module, set a fixed time interval to record the power data, screen out abnormal power points, calculate the power change value between adjacent time points and record the time stamp to obtain the photovoltaic power sequence;

[0054] Obtain the input power, voltage value, and current value of the photovoltaic module. First, obtain the measured values of the current voltage (U 当前 ) and current (I 当前 ) through the sensors of the photovoltaic module, and based on the power calculation formula: P 当前 =U 当前 ×I 当前 , where P 当前 is the photovoltaic input power at the current moment (unit: W), U 当前 is the voltage of the photovoltaic module (unit: V), and I 当前 is the current of the photovoltaic module (unit: ampere, A). Then set a fixed time interval (Δt, unit: s) for data recording. At the end of each time interval, repeat to obtain new voltage and current measurement values and calculate the new power (P 下一时刻 ). Then construct a time series data table, including the timestamp (T 时间 ), voltage (U 时间 ), current (I 时间 ), and power (P 时间 ) values. After that, screen out abnormal power points. Judge by setting a reasonable power threshold range ([P 最小 , P 最大 ). If the current power P 当前 is not within this range, mark it as abnormal data and eliminate it. For example, set the minimum power threshold to 10 W (P 最小 =10 W) and the maximum power threshold to 500 W (P 最大 =500 W). If the power value P 当前 =600 W at a certain moment exceeds the range, eliminate this data point. Then calculate the power change value between adjacent time points: ΔP=P 下一时刻 -P 当前 , where ΔP represents the power change amount between adjacent time points (unit: W), P 下一时刻 represents the photovoltaic input power at the next time point (unit: W), and P 当前 represents the photovoltaic input power at the current time point (unit: W). Subsequently, record the corresponding timestamp T 时间 (unit: s), and all the power change data forms a complete photovoltaic power sequence.

[0055] S102: Select data of consecutive time points from the photovoltaic power sequence, set a calculation window to take the average of the change rates of multiple consecutive moments, calculate the derivative of power with respect to time, obtain the power change rate within the specified time, record the direction of the power change trend, and obtain the photovoltaic input power change rate;

[0056] Select data of consecutive time points from the photovoltaic power sequence, set a calculation window (W 窗口大小, unit: second, s). For example, if a 5-minute (300 seconds) time window is selected, the average rate of change at multiple consecutive moments is calculated within this time window. Specifically, during execution, for the power change amounts (ΔP1, ΔP2, …, ΔP 起始 , T 起始 +W 窗口大小 ) within the time window [T n , calculate their average value: Among them, is the average power change amount within this time window (unit: W), n is the number of data points within the calculation window (unitless), and ΔP i is the power change amount for the i-th time interval (unit: W). Subsequently, calculate the derivative of power with respect to time, that is, the power change rate: Among them, R P is the photovoltaic power change rate (unit: W / s), is the average power change amount within the time window (unit: W), and Δt 时间间隔 is the time interval (unit: s). Assume that the power change amounts within the 5-minute window are 10W, -5W, 8W, 3W, and 4W in sequence, then the average rate of change is calculated as follows: If the time interval Δt 时间间隔 takes 60 seconds, then the power change rate: Subsequently, calculate the photovoltaic power change trend direction based on the change rate. If R P >0, it is recorded as an upward trend. If R P <0, it is recorded as a downward trend. If R P =0, it is recorded as a stable trend, and finally, the photovoltaic input power change rate is obtained.

[0057] S103: Based on the photovoltaic input power change rate, set the photovoltaic power fluctuation threshold, compare the current change rate with the fluctuation threshold. If the change rate exceeds the fluctuation threshold, mark the photovoltaic power as being in an upward or downward trend according to the change direction. If it does not exceed the fluctuation threshold, mark it as a stable trend, and at the same time record the current photovoltaic power level to obtain the photovoltaic power change information;

[0058] Set the photovoltaic power fluctuation threshold (R 波动阈值 , unit: W / s) based on the photovoltaic input power change rate. By comparing the current change rate (R P ) with the fluctuation threshold R 波动阈值 to judge the power change situation. If R P >R 波动阈值 , then mark the photovoltaic power as an upward trend; if R P <-R 波动阈值 , then mark the photovoltaic power as a downward trend; if -R 波动阈值 ≤R P ≤R波动阈值 , the photovoltaic power is marked as a stable trend. For example, set the fluctuation threshold: R 波动阈值 = 0.05W / s. When the calculated power change rate R P = 0.067W / s, it satisfies R P > R 波动阈值 , so the power change trend is marked as an upward trend; when R P = -0.08W / s, it satisfies R P < -R 波动阈值 , so the power change trend is marked as a downward trend; when R P = 0.03W / s, it satisfies the stable trend condition, then the power is marked as a stable trend, and the current photovoltaic power level P 当前 (unit: W) is recorded, and finally the photovoltaic power change information is obtained.

[0059] Analyze the photovoltaic power level based on the photovoltaic power change information, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and the specific steps to obtain the load power classification result are as follows:

[0060] S201: Obtain the current photovoltaic power level from the photovoltaic power change information, calculate the power change rate, and divide the power fluctuation amplitude into intervals. Set the photovoltaic power level classification threshold, compare the current power level with the classification threshold, and determine whether the photovoltaic power is in a sufficient, critical, or insufficient state to obtain the photovoltaic power level status;

[0061] First, obtain the photovoltaic power P' 当前时刻 (unit: watt, W) at the current time point, and then calculate the power change rate R 功率变化速率 . The calculation process is as follows: Among them, P' 前一时刻 is the photovoltaic power at the previous time point (unit: W), T 当前时刻 is the current timestamp (unit: second, s), and T 前一时刻 is the previous timestamp (unit: s). For example, if the current photovoltaic power P' 当前时刻 = 400W, the photovoltaic power P' 前一时刻 = 380W at the previous moment, and the time interval T 当前时刻 - T 前一时刻

[0062] = 60s, then the power change rate is calculated as follows: Subsequently, divide the power fluctuation amplitude into intervals, set the photovoltaic power level classification thresholds P 低功率阈值 and P 高功率阈值 , and perform power level judgment. If P' 当前时刻 > P 高功率阈值Then the photovoltaic power is in a sufficient state. If P 低功率阈值 ≤P′ 当前时刻 ≤P 高功率阈值 Then it is in a critical state. If P′ 当前时刻 <P 低功率阈值 Then it is in a deficient state. For example, set the low power threshold P 低功率阈值 = 200W, the high power threshold P 高功率阈值 = 350W. Then when the current photovoltaic power P′ 当前时刻 = 400W, the photovoltaic power is in a sufficient state. When P′ 当前时刻 = 300W, it is in a critical state. When P′ 当前时刻 = 150W, it is in a deficient state. Finally, the photovoltaic power level state is obtained.

[0063] S202: Based on the photovoltaic power level state, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment. Set the operating mode classification criteria, determine whether the equipment is in continuous operation, intermittent operation, or standby mode, and record the characteristic parameters of each equipment to obtain the power supply equipment characteristic data;

[0064] Obtain the instantaneous power demand P 设备功率需求 (unit: W), the voltage adaptation range [U 设备最低电压 , U 设备最高电压 (unit: V), and the operating mode of the off-grid power supply equipment. Set the operating mode classification criteria, and determine whether it belongs to the continuous operation mode, intermittent operation mode, or standby mode according to the equipment operation method. For each equipment, calculate its instantaneous power demand and compare whether its voltage adaptation range meets the current photovoltaic power supply voltage U 光伏供电电压 . If the condition is met: U 设备最低电压 ≤U 光伏供电电压 ≤U 设备最高电压 , then the equipment voltage is adapted. If the power demand P 设备功率需求 of the equipment is within the allowable range of the photovoltaic power level state, then mark the equipment as power supply available. Subsequently, record the characteristic parameters of each equipment, including P 设备功率需求 , U 设备最低电压 , U 设备最高电压 , the operating mode, and the power demand situation. For example, the power demand P 设备功率需求 of equipment A = 100W, the lowest voltage U 设备最低电压 of the equipment = 220V, the highest voltage U 设备最高电压 of the equipment = 240V, and the operating mode is continuous operation. If the current photovoltaic power supply voltage U 光伏供电电压 = 230V meets the voltage adaptation range, then equipment A is marked as a power supply available equipment. Finally, the power supply equipment characteristic data is obtained.

[0065] S203: Based on the characteristic data of the power supply equipment, calculate the power demand of the equipment under each operation mode according to the photovoltaic power level status, screen the equipment with priority power supply, the equipment that can operate intermittently, and the equipment that can be turned off when the photovoltaic power is insufficient, set the power supply priority of the equipment, and obtain the load power classification result;

[0066] Calculate the power demand of the equipment under each operation mode according to the photovoltaic power level status. For continuously operating equipment, calculate its total power demand P 连续设备功率需求总和 : P 连续设备功率需求总和 = ∑

[0067] P 单个连续设备功率需求 , where P 单个连续设备功率需求 is the power demand of a single device (unit: W). For intermittently operating equipment, calculate its total power demand P 间歇设备功率需求总和 : P 间歇设备功率需求总和 = ∑P 单个间歇设备功率需求 . For standby mode equipment, calculate its standby power P 待机设备功率需求总和 : P 待机设备功率需求总和 = ∑P 单个待机设备功率需求 . Then screen the equipment with priority power supply, the equipment that can operate intermittently, and the equipment that can be turned off when the photovoltaic power is insufficient, set the power supply priority of the equipment. If the photovoltaic power status is sufficient, give priority to power supply to continuously operating equipment. If the photovoltaic power status is critical, give priority to power supply to continuously operating equipment and partially supply power to intermittently operating equipment. If the photovoltaic power status is insufficient, turn off the intermittently operating equipment and only maintain some necessary continuously operating equipment. For example, if the total power demand of continuous equipment P 连续设备功率需求总和 = 300W, the total power demand of intermittent equipment P 间歇设备功率需求总和 = 100W, the total power demand of standby equipment P 待机设备功率需求总和 = 50W, and the current photovoltaic power P 当前时刻 = 350W, then only supply power to continuously operating equipment, and finally obtain the load power classification result.

[0068] Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and the specific steps to obtain the photovoltaic power supply adjustment result are as follows:

[0069] S301: Based on the load power classification result, obtain the instantaneous power demand of the equipment with priority power supply, the equipment that can operate intermittently, and the equipment that can be turned off when the photovoltaic power is insufficient, calculate the total power demand of each type of equipment, and obtain the total power demand of the classified equipment;

[0070] Obtain the instantaneous power demand of the equipment with priority power supply, the equipment that can operate intermittently, and the equipment that can be turned off when the photovoltaic power is insufficient. Define the instantaneous power demand of the equipment with priority power supply as D 优先设备功率 (unit: watt, W), and the instantaneous power demand of the intermittently operating equipment as D间歇设备功率 (Unit: W), the instantaneous power demand of the equipment that can be turned off when the photovoltaic power is insufficient is D 可关闭设备功率 (Unit: W), calculate the total power demand of each type of equipment, and the specific calculation is as follows: D 优先设备总功率 =∑D 单个优先设备功率 ,

[0071] D 间歇设备总功率 =∑D 单个间歇设备功率 , D 可关闭设备总功率 =∑D 单个可关闭设备功率 . Among them, D 单个优先设备功率 represents the power demand of a single priority power supply equipment (unit: W),

[0072] D 单个间歇设备功率 represents the power demand of a single intermittently operable equipment (unit: W),

[0073] D 单个可关闭设备功率 represents the power demand of a single equipment that can be turned off when the photovoltaic power is insufficient (unit: W), and then calculate the total power demand of all classified equipment: D 分类设备总功率 =D 优先设备总功率 +

[0074] D 间歇设备总功率 +D 可关闭设备总功率 . For example, assuming that the demands of the priority power supply equipment are 150W, 200W, and 250W respectively, then its total power demand is: D 优先设备总功率 =150 + 200 + 250 = 600W. The demands of the intermittently operable equipment are 100W and 150W respectively, then its total power demand is: D 间歇设备总功率 =100 + 150 = 250W. The demands of the equipment that can be turned off when the photovoltaic power is insufficient are 50W and 80W, then its total power demand is: D 可关闭设备总功率 =50 + 80 = 130W. Finally, the total power demand of the classified equipment is obtained: D 分类设备总功率 =600 + 250 + 130 = 980W.

[0075] S302: Based on the total power demand of the classified equipment, obtain the current photovoltaic power level, calculate the power supply deviation between the photovoltaic power and the total power demand, set the power supply deviation threshold. If the deviation exceeds the deviation threshold, calculate the adjustable power according to the demand ratio of each type of equipment. If the deviation is within the deviation threshold range, keep the current power supply state unchanged to obtain the photovoltaic power matching result;

[0076] Obtain the current photovoltaic power level G 当前光伏功率 (Unit: W), calculate the power supply deviation E between the photovoltaic power and the total power demand 功率供应偏差 , and the calculation formula is as follows: E 功率供应偏差 =

[0077] G 当前光伏功率 -D 分类设备总功率 wherein, G 当前光伏功率 is the current photovoltaic power supply (unit: W), and D 分类设备总功率 is the total power demand obtained from the foregoing calculation (unit: W). A power supply deviation threshold E 偏差阈值 (unit: W) is set. If the deviation satisfies |E 功率供应偏差 | > E 偏差阈值 , then the adjustable power is calculated. The calculation process is as follows: wherein, D 可调节功率 represents the power value adjusted according to the power supply deviation (unit: W), and D 间歇设备总功率 is the total power demand of the intermittently operable equipment (unit: W). If the deviation is within the threshold range, that is, |E 功率供应偏差 | ≤ E 偏差阈值 , then the current power supply state remains unchanged. For example, if the current photovoltaic power G 当前光伏功率 = 1100 W, the total demand D 分类设备总功率 of the classification equipment = 980 W, the power supply deviation, E 功率供应偏差 = 1100 - 980 = 120 W, and the set deviation threshold E 偏差阈值 = 100 W. Since 120 W > 100 W, the adjustable power is calculated: Finally, the photovoltaic power matching result is obtained.

[0078] S303: Based on the photovoltaic power matching result, adjust the power distribution according to the power supply stability requirements of the priority power supply equipment. If the power supply deviation is positive, increase the power supply of the intermittently operable equipment. If the deviation is negative, reduce the power supply of the equipment that can be turned off when the photovoltaic power is insufficient, and reallocate the power supply sequence to obtain the photovoltaic power supply adjustment result;

[0079] Adjust the power distribution according to the power supply stability requirements of the priority power supply equipment. If the power supply deviation is positive, that is, E 功率供应偏差 > 0, then increase the power supply of the intermittently operable equipment. The adjusted power supply D 调整后间歇设备功率 is calculated as follows: D 调整后间歇设备功率 = D 间歇设备总功率 +

[0080] D 可调节功率 . If the deviation is negative, that is, E 功率供应偏差 < 0, then reduce the power supply of the equipment that can be turned off when the photovoltaic power is insufficient. The adjusted power supply D 调整后可关闭设备功率 of the turn-off equipment is calculated as follows: D 调整后可关闭设备功率 = D 可关闭设备总功率 - D 可调节功率, subsequently, reallocate the power supply sequence, prioritize ensuring the power demand of the priority power supply equipment, and after meeting the demand of the priority power supply equipment, supply power according to the adjusted power supply of the intermittent operation equipment D 调整后间歇设备功率 and the power supply of the turn-offable equipment D 调整后可关闭设备功率 For example, if the calculated D 可调节功率 = 30.61W, then adjust the power supply of the intermittent equipment: D 调整后间歇设备功率 = 250 + 30.61 = 280.61W. If the power deviation is negative, such as E 功率供应偏差 = -50W, then adjust the power supply of the turn-offable equipment: D 调整后可关闭设备功率 = 130 - 50 = 80W, and finally obtain the photovoltaic power supply adjustment result.

[0081] Based on the photovoltaic power supply adjustment result, connect the equipment to the DC bus of the corresponding voltage, calculate the total power demand of each type of DC bus and compare it with the available power of the current bus, and adjust the power supply connection method of the equipment. The specific steps to obtain the hierarchical bus power supply distribution information are as follows:

[0082] S401: Based on the photovoltaic power supply adjustment result, obtain the voltage adaptation range of each off-grid power supply equipment, screen the equipment that meets the working requirements of multiple types of DC buses, and match the bus that meets the operation requirements according to the rated working voltage of the equipment and the rated voltage of each bus, and initially determine the power supply connection relationship of the equipment to obtain the initial bus access situation of the equipment;

[0083] To obtain the voltage adaptation range of each off-grid power supply equipment, first determine the minimum adaptation voltage U 设备最低电压,i (unit: V) and the maximum adaptation voltage U 设备最高电压,i (unit: V), where i represents the equipment number. Then screen the equipment that meets the working requirements of multiple types of DC buses, and match according to the rated working voltage U 设备额定电压,i (unit: V) of the equipment and the rated voltage U 母线额定电压,j (unit: V) of each bus. If the equipment meets the condition: U 设备最低电压,i ≤U 母线额定电压,j ≤U 设备最高电压,i , then the equipment can be connected to the bus j. Subsequently, screen all the qualified equipment and allocate it to each type of bus. For example, assume that the adaptation voltage range of a certain equipment A is U 设备最低电压,A = 220V to U 设备最高电压,A = 240V, and the rated voltage U 母线额定电压,B of bus B = 230V, which meets the above conditions, then equipment A can be connected to bus B, and finally determine the initial bus access situation of the equipment.

[0084] S402: Based on the initial bus connection situation of the device, obtain the total power demand of the devices connected to each type of bus, calculate the available power of the current bus, set the bus power supply threshold, calculate the power supply deviation of each type of bus. If the deviation value exceeds the bus power supply threshold, mark the bus as in a power shortage or overload state, and calculate the standby voltage corresponding to each device to obtain the bus power supply analysis result;

[0085] Obtain the total power demand of the devices connected to each type of bus and calculate the available power W of the current bus 母线可供功率,j (unit: watt, W), set the bus power supply threshold W 母线供应阈值,j (unit: W), calculate the power supply deviation W of each type of bus 母线功率偏差,j , and the calculation formula is as follows: W 母线功率偏差,j = W 母线可供功率,j - ∑W 设备功率需求,i,j , where W 设备功率需求,i,j is the power demand of device i connected to bus j (unit: W). If the calculated deviation value satisfies: |W 母线功率偏差,j | >

[0086] W 母线供应阈值,j , then mark bus j as in a power shortage or overload state, and calculate the standby voltage U backup,i (unit: V). The standby voltage is screened according to the list of buses that the device can access, and the calculation formula is as follows:

[0087]

[0088] Among them, U backup,i is the standby voltage of device i (unit: V); U bus,j is the rated voltage of bus j (unit: V); W available,j is the available power of bus j (unit: W); W load,i,j is the power demand of device i on bus j (unit: W); N bus is the total number of optional buses (unitless); β is an adjustment coefficient (unitless) used to control the impact of the bus load power on the standby voltage calculation; γ is a standby voltage correction coefficient (unitless).

[0089] Suppose there are three DC buses numbered j = 1, 2, 3, and their rated voltages are: Bus 1: U bus,1

[0090] = 220V, Bus 2: U bus,2 = 230V, Bus 3: U bus,3 = 240V.

[0091] The power demand of device X on each bus is: Bus 1: W load,X,1= 300 W, Bus 2: W load,X,2 = 200 W, Bus 3: W load,X,3 = 500 W.

[0092] Available power of each bus: Bus 1: W available,1 = 4000 W, Bus 2: W available,2 = 4500 W, Bus 3: W available,3 = 5000 W.

[0093] Setting of the adjustment coefficient β: This coefficient is used to suppress the influence of high-load devices on the standby voltage, making the influence of buses with lighter loads on the standby voltage greater. The empirical setting range is 0.005 - 0.02. When the device load is high, a larger β value should be selected to reduce the dependence of this device on high-load buses. Since device X has the largest load on Bus 3, set β = 0.01 to moderately suppress the high-load influence.

[0094] Setting of the standby voltage correction coefficient γ: This coefficient is used to adjust the standby voltage so that it takes into account the overall bus load situation and reflects the power supply capacity of the bus. The empirical setting range is 0.02 - 0.1. When the overall bus load is light, a larger γ value should be selected to increase the influence of the standby voltage of this bus. Since the available powers of Buses 1, 2, and 3 are large, γ = 0.05 is selected so that the standby voltage calculation can appropriately consider the overall bus power supply situation.

[0095] Calculating the standby voltage of device X:

[0096]

[0097] Calculating the exponential decay term: e -0.01×300 = 0.7408, e -0.01×200 = 0.8187, e -0.01×500 = 0.6065;

[0098] Calculating the numerator: (220 × 0.7408) + (230 × 0.8187) + (240 × 0.6065)

[0099] = 163.0 + 188.3 + 145.6 = 496.9;

[0100] Calculating the denominator: 0.7408 + 0.8187 + 0.6065 = 2.166;

[0101] Exponentially-decayed weighted average voltage:

[0102] Calculating the total available power: 4000 + 4500 + 5000 = 13500 W;

[0103] Total power demand of the computing device: 300 + 200 + 500 = 1000W;

[0104] Calculate the correction factor:

[0105] Final calculated backup voltage level: U backup,X = 229.4 × 1.675 = 384.4V.

[0106] The backup voltage U of device X backup,X = 384.4V, which is higher than the highest voltage 240V that it could originally be connected to the bus. This indicates that in high-load situations, the device may need to prioritize the bus migration plan for the higher voltage level. If the load conditions of other devices are different, the calculated results of the backup voltage will also vary, ensuring that the system can preferentially match the appropriate bus during adjustment, rather than simply distributing according to the rated voltage of the bus.

[0107] Finally, this backup voltage calculation method provides a dynamically adaptable backup bus distribution plan for the device, enabling devices with different power requirements to flexibly match the appropriate voltage level, thereby optimizing the overall power supply strategy of the bus and obtaining the analysis results of the bus power supply.

[0108] S403: Based on the analysis results of the bus power supply, screen the buses with insufficient power supply or overload, determine the list of devices that need to be adjusted. If a certain bus is in an overloaded state, preferentially adjust the intermittently operable devices to the bus with a lower voltage. If the bus has insufficient power supply, adjust some low-power devices to the bus with a higher voltage to keep the deviation of the bus power supply within the range of the bus power supply threshold, and obtain the hierarchical bus power supply distribution information;

[0109] Screen the buses with insufficient power supply or overload, determine the list of devices that need to be adjusted. If a certain bus is in an overloaded state, preferentially adjust the intermittently operable devices to the bus with a lower voltage. For example, if the power supply deviation of bus D is W 母线功率偏差,D = 600W, and the rated power demand of the intermittently operable device E is W 设备功率需求,E,D = 300W, and the rated voltage U of the backup bus F that it can be connected to is 备用母线额定电压,E = 210V, then device E is migrated to bus F. After adjustment, the power supply deviation of bus D is updated to: W 母线功率偏差,D = 600 - 300 = 300W. If the bus has insufficient power supply, adjust some low-power devices to the bus with a higher voltage to keep the deviation of the bus power supply within the range of the bus power supply threshold. For example, bus G has insufficient power supply, and the deviation value is W 母线功率偏差,G = -500W, and the power demand of the low-power device H is W 设备功率需求,H,G = 200W, which can be migrated to the backup bus I. Then the deviation after adjustment is updated to: W 母线功率偏差,G=-500 + 200 = -300 W, and finally obtain the hierarchical bus power supply distribution information.

[0110] The specific steps to obtain the power supply status of each type of bus from the hierarchical bus power supply distribution information and adjust the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result are as follows:

[0111] S501: Based on the hierarchical bus power supply distribution information, obtain the power supply status of each type of DC bus, calculate the current power supply of the bus, set a power matching error threshold according to the power demand of the photovoltaic energy storage power supply device, calculate the error value between the current power supply and the demand of the energy storage power supply device. If the error exceeds the error threshold, mark it as an abnormal power supply deviation state to obtain the power supply matching error analysis result;

[0112] Obtain the power supply status of each type of DC bus. First, determine the current available power W of each bus 母线可供功率,j (unit: watt, W), calculate the current power supply W of the bus 母线供电功率,j , and the calculation formula is as follows: W 母线供电功率,j = W 母线可供功率,j -∑W 设备功率需求,i,j , where,

[0113] W 母线供电功率,j represents the current power supply of bus j (unit: W); W 母线可供功率,j represents the maximum available power of bus j (unit: W); W 设备功率需求,i,j represents the power required by device i connected to bus j (unit: W); ∑W 设备功率需求,i,j represents the total power demand of all devices on bus j (unit: W). Then, according to the power demand W of the photovoltaic energy storage power supply device 储能设备需求,j (unit: W), set a power matching error threshold W 匹配误差阈值,j (unit: W), calculate the error value W between the current power supply and the demand of the energy storage power supply device 供电误差,j : W 供电误差,j = W 母线供电功率,j -W 储能设备需求,j , where, W 供电误差,j represents the error between the power supply of bus j and the demand of the energy storage device (unit: W); W 储能设备需求,j is the power required by the energy storage device on bus j (unit: W). If the calculated error value satisfies: |W 供电误差,j |>W 匹配误差阈值,j , then mark bus j as an abnormal power supply deviation state. For example, if the available power of bus A W 母线可供功率,A = 5000 W, and the total power demand of the connected devices ∑

[0114] W 设备功率需求,i,A= 4600 W, then the bus power supply calculation is as follows: W 母线供电功率,A

[0115] = 5000 - 4600 = 400 W. Assume the power demand of the photovoltaic energy storage device on bus A is W 储能设备需求,A = 500 W, then the power supply error calculation is as follows: W 供电误差,A

[0116] = 400 - 500 = -100 W. If the set matching error threshold W 匹配误差阈值,A = 50 W, since |-100| > 50, then bus A is in an abnormal power supply deviation state, and finally the power supply matching error analysis result is obtained.

[0117] S502: Based on the power supply matching error analysis result, calculate the current power supply capacity. If the power supply deviation is negative, reduce the power supply of the devices that can be turned off when the photovoltaic power is insufficient, and adjust the power supply priority of the priority power supply devices. If the power supply deviation is positive, increase the power supply of the intermittently operating devices, recalculate the matching error with the adjusted power supply data, and obtain the key load power supply adjustment value;

[0118] Calculate the current power supply capacity. If the power supply deviation is negative, i.e., W 供电误差,j <0, then reduce the power supply of the devices that can be turned off when the photovoltaic power is insufficient W adjust,off,j , and the adjusted device power supply calculation is as follows:

[0119]

[0120] Among them, W adjust,off,j represents the power supply of the devices that can be turned off on bus j after adjustment (unit: W); W off,j represents the original power supply of the devices that can be turned off on bus j (unit: W); W error,j represents the power supply error of bus j (unit: W), that is, the deviation between the current power supply and the energy storage demand; ∑W off,j represents the total power supply of all devices that can be turned off on bus j (unit: W); ∑W intermittent,j represents the total power supply of all intermittently operating devices on bus j (unit: W).

[0121] If the power supply deviation is positive, i.e., W error,j > 0, then increase the power supply of the intermittently operating devices W adjust,int,j , and the adjusted intermittent device power supply calculation is as follows:

[0122]

[0123] Among them, W adjust,int,j represents the power supply of the intermittently operating devices on bus j after adjustment (unit: W); Wintermittent,j Indicates the power supply of the originally intermittently operating equipment on busbar j (unit: W).

[0124] If the power supply error of busbar B is W error,B =-150 W, the original power supply of the equipment can be turned off, W off,B =500 W, and the original power supply of the intermittent equipment is W intermittent,B =300 W, then the adjusted power supply is calculated as follows:

[0125]

[0126] If the power supply error of busbar C is W error,C =120 W, and the original power supply of the intermittent equipment is W intermittent,C =600 W, the original power supply of the equipment that can be turned off is W off,C =400 W, then the adjusted power supply is calculated as follows:

[0127]

[0128] Finally, the power supply adjustment value for the critical load is obtained.

[0129] S503: Analyze the change trend of the photovoltaic input power and the charge and discharge status of the current energy storage device based on the power supply adjustment value of the critical load, set the energy storage power adjustment threshold. If the photovoltaic power is on the rise, increase the charging power of the energy storage device; if it is on the decline, increase the discharge power of the energy storage device to maintain the stability of the busbar power and obtain the photovoltaic off-grid power distribution result;

[0130] First, obtain the change rate R of the photovoltaic power solar (unit: W / s), set the energy storage power adjustment threshold W storage,threshold (unit: W). If the photovoltaic power is on the rise, that is, R solar >0, then increase the charging power W of the energy storage device storage,charge,adj (unit: W), and the adjustment calculation is as follows: W storage,charge,adj =W storage,charge +R solar ×T adjust If the photovoltaic power is on the decline, that is, R solar <0, then increase the discharge power W of the energy storage device storage,discharge,adj (unit: W), and the adjustment calculation is as follows: W storage,discharge,adj =W storage,discharge -R solar ×T adjust Among them, W storage,charge,adj represents the charging power of the adjusted energy storage device (unit: W); W storage,charge represents the current charging power of the energy storage device (unit: W);

[0131] W storage,discharge,adj represents the discharge power of the energy storage device after adjustment (unit: W);

[0132] W storage,discharge represents the discharge power of the current energy storage device (unit: W); R solar represents the change rate of the photovoltaic power (unit: W / s), that is, the increase or decrease amplitude of the photovoltaic power per unit time; T adjust represents the adjustment time interval (unit: s), which is used to determine the power change amount of the adjustment.

[0133] If the change rate of the photovoltaic power R solar = 5 W / s, the current charging power of the energy storage W storage,charge

[0134] = 1000 W, and the adjustment time interval T adjust = 60 s, then the adjusted charging power is calculated as follows:

[0135] W storage,charge,adj = 1000 + (5×60) = 1300 W;

[0136] If the change rate of the photovoltaic power R solar = -4 W / s, the current discharge power of the energy storage W storage,discharge = 1200 W, then the adjusted discharge power is calculated as follows:

[0137] W storage,discharge,adj = 1200 - (4×60) = 960 W;

[0138] Finally, the photovoltaic off-grid power distribution result is obtained.

[0139] Please refer to Figure 2 , a power distribution system for photovoltaic off-grid, the system includes:

[0140] The photovoltaic power fluctuation detection module obtains the input power of the photovoltaic module and calculates the instantaneous change rate, judges the change trend of the photovoltaic power, records the current photovoltaic power level, and obtains the photovoltaic power change information;

[0141] The load characteristic analysis and classification module analyzes the photovoltaic power level based on the photovoltaic power change information, obtains the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply equipment, classifies multiple types of power supply equipment, and obtains the load power classification result;

[0142] The power supply priority adjustment module calculates the total power demand of each type of off-grid power supply equipment based on the load power classification result, adjusts the power supply priority of each type of electrical equipment, and obtains the photovoltaic power supply adjustment result;

[0143] Based on the photovoltaic power supply adjustment result, the hierarchical bus power supply management module connects the equipment to the DC bus with the corresponding voltage, calculates the total power demand of each type of DC bus and compares it with the available power of the current bus, adjusts the power supply connection mode of the equipment, and obtains the hierarchical bus power supply distribution information;

[0144] The energy storage dynamic regulation module obtains the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjusts the charge and discharge of the energy storage equipment according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result.

[0145] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any person skilled in the art may use the disclosed technical content to make changes or modifications into equivalent embodiments with equivalent changes and apply them to other fields. However, as long as it does not depart from the technical content of the technical solution of the present invention, any simple modification, equivalent change and modification made to the above embodiments based on the technical essence of the present invention still belong to the protection scope of the technical solution of the present invention.

Claims

1. A power distribution method for photovoltaic off-grid, characterized in that It includes the following steps: S1: Obtain the input power of the photovoltaic module and calculate the instantaneous change rate, judge the photovoltaic power change trend, record the current photovoltaic power level, and obtain the photovoltaic power change information; S2: Analyze the photovoltaic power level based on the photovoltaic power change information, obtain the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and obtain the load power classification result; S3: Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and obtain the photovoltaic power supply adjustment result; S4: Based on the photovoltaic power supply adjustment result, connect the equipment to the DC bus with the corresponding voltage, calculate the total power demand of each type of DC bus and compare it with the available power of the current bus, adjust the power supply connection method of the equipment, and obtain the hierarchical bus power supply distribution information; S5: Obtain the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjust the charge and discharge of the energy storage device according to the photovoltaic input power change trend to obtain the photovoltaic off-grid power distribution result.

2. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: The photovoltaic power change information includes the photovoltaic power change trend category, the photovoltaic power fluctuation amplitude, and the current photovoltaic power level. The load power classification result includes the priority power supply equipment category, the intermittently operable equipment category, and the equipment category that can be turned off when the photovoltaic power is insufficient. The photovoltaic power supply adjustment result includes the power supply priority of each type of equipment, the maximum allowable power of the adjustable load, and the optimal load reduction power of the non-critical load. The hierarchical bus power supply distribution information includes the total power demand of the voltage bus, the available power of the current bus, the bus power supply deviation, and the adjusted equipment power supply connection method. The photovoltaic off-grid power distribution result includes the power supply power of the critical load, the charge and discharge plan of the energy storage device, and the dynamic adjustment of the photovoltaic input power.

3. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: The specific steps to obtain the input power of the photovoltaic module and calculate the instantaneous change rate, judge the photovoltaic power change trend, and record the current photovoltaic power level to obtain the photovoltaic power change information are as follows: S101: Obtain the input power, voltage value and current value of the photovoltaic module, set a fixed time interval to record the power data, screen abnormal power points, calculate the power change value between adjacent time points and record the time stamp to obtain the photovoltaic power sequence; S102: Select the data of consecutive time points from the photovoltaic power sequence, set a calculation window to take the average of the change rates at multiple consecutive moments, calculate the derivative of power with respect to time, obtain the power change rate within the specified time, and record the power change trend direction to obtain the photovoltaic input power change rate; S103: Based on the photovoltaic input power change rate, set a photovoltaic power fluctuation threshold, compare the current change rate with the fluctuation threshold. If the change rate exceeds the fluctuation threshold, mark the photovoltaic power as rising or falling according to the change direction. If it does not exceed the fluctuation threshold, mark it as a stable trend, and at the same time record the current photovoltaic power level to obtain the photovoltaic power change information.

4. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: Analyze the photovoltaic power level based on the photovoltaic power change information, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment, classify multiple types of power supply equipment, and the specific steps to obtain the load power classification result are as follows: S201: Obtain the current photovoltaic power level from the photovoltaic power change information, calculate the power change rate, divide the power fluctuation amplitude into intervals, set the photovoltaic power level classification threshold, compare the current power level with the classification threshold, and determine whether the photovoltaic power is in a sufficient, critical, or insufficient state to obtain the photovoltaic power level state; S202: Based on the photovoltaic power level state, obtain the instantaneous power demand, voltage adaptation range, and operating mode of the off-grid power supply equipment, set the operating mode classification standard, determine whether the equipment is in continuous operation, intermittent operation, or standby mode, and record the characteristic parameters of each equipment to obtain the power supply equipment characteristic data; S203: Based on the power supply equipment characteristic data, calculate the equipment power demand in each operating mode according to the photovoltaic power level state, screen the priority power supply equipment, intermittently operable equipment, and equipment that can be turned off when the photovoltaic power is insufficient, set the power supply priority of the equipment, and obtain the load power classification result.

5. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: Based on the load power classification result, calculate the total power demand of each type of off-grid power supply equipment, adjust the power supply priority of each type of electrical equipment, and the specific steps to obtain the photovoltaic power supply adjustment result are as follows: S301: Based on the load power classification result, obtain the instantaneous power demand of the priority power supply equipment, intermittently operable equipment, and equipment that can be turned off when the photovoltaic power is insufficient, calculate the total power demand of each type of equipment, and obtain the total power demand of the classified equipment; S302: Based on the total power demand of the classified equipment, obtain the current photovoltaic power level, calculate the power supply deviation between the photovoltaic power and the total power demand, set the power supply deviation threshold. If the deviation exceeds the deviation threshold, calculate the adjustable power according to the demand ratio of each type of equipment. If the deviation is within the deviation threshold, keep the current power supply state unchanged to obtain the photovoltaic power matching result; S303: Based on the photovoltaic power matching result, adjust the power distribution according to the power supply stability requirements of the priority power supply equipment. If the power supply deviation is positive, increase the power supply power of the intermittently operable equipment. If the deviation is negative, reduce the power supply power of the equipment that can be turned off when the photovoltaic power is insufficient, and reallocate the power supply order to obtain the photovoltaic power supply adjustment result.

6. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: Based on the photovoltaic power supply adjustment result, connect the equipment to the DC bus with the corresponding voltage, calculate the total power demand of each type of DC bus and compare it with the available power of the current bus, adjust the power supply connection method of the equipment, and the specific steps to obtain the hierarchical bus power supply distribution information are as follows: S401: Based on the photovoltaic power supply adjustment result, obtain the voltage adaptation range of each off-grid power supply equipment, screen the equipment that meets the working requirements of multiple types of DC buses, match the bus that meets the operating requirements according to the rated working voltage of the equipment and the rated voltage of each bus, and initially determine the power supply connection relationship of the equipment to obtain the initial bus access situation of the equipment; S402: Based on the initial bus connection situation of the device, obtain the total power demand of the devices connected to each type of bus, calculate the available power of the current bus, set the bus power supply threshold, calculate the power supply deviation of each type of bus. If the deviation value exceeds the bus power supply threshold, mark the bus as in a power supply shortage or overload state, and calculate the standby voltage corresponding to each device, obtaining the bus power supply analysis result; S403: Based on the bus power supply analysis result, screen the buses with power supply shortage or overload, determine the list of devices that need to be adjusted. If a certain bus is in an overload state, preferentially adjust the intermittently operable devices to the bus with a lower voltage. If the bus has a power supply shortage, adjust some low-power devices to the bus with a higher voltage, so that the bus power supply deviation is maintained within the bus power supply threshold range, obtaining the hierarchical bus power supply distribution information.

7. The power distribution method for photovoltaic off-grid according to claim 6, characterized in that: For calculating the standby voltage corresponding to each device, the formula is used: Among them, U backup,i is the standby voltage of device i, U bus,j is the rated voltage of bus j, W available,j is the available power of bus j, W load,i,j is the power demand of device i at bus j, N bus is the optional total number of buses, β is the adjustment coefficient, and γ is the standby voltage correction coefficient.

8. The power distribution method for photovoltaic off-grid according to claim 1, characterized in that: The specific steps for obtaining the power supply state of each type of bus from the hierarchical bus power supply distribution information and adjusting the charge and discharge of the energy storage device according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result are as follows: S501: Based on the hierarchical bus power supply distribution information, obtain the power supply state of each type of DC bus, calculate the current power supply of the bus, set the power matching error threshold according to the power demand of the photovoltaic energy storage power supply device, calculate the error value between the current power supply and the demand of the energy storage power supply device. If the error exceeds the error threshold, mark it as an abnormal power supply deviation state, obtaining the power supply matching error analysis result; S502: Based on the power supply matching error analysis result, calculate the current power supply capacity. If the power supply deviation is negative, reduce the power supply of the devices that can be turned off when the photovoltaic power is insufficient, and adjust the power supply priority of the preferentially powered devices. If the power supply deviation is positive, increase the power supply of the intermittently operable devices, and recalculate the matching error for the adjusted power supply data, obtaining the critical load power supply adjustment value; S503: Based on the critical load power supply adjustment value, analyze the change trend of the photovoltaic input power and the current charge and discharge state of the energy storage device, set the energy storage power adjustment threshold. If the photovoltaic power is on an upward trend, increase the charging power of the energy storage device. If it is on a downward trend, increase the discharge power of the energy storage device to maintain the stability of the bus power, obtaining the photovoltaic off-grid power distribution result.

9. The power distribution method for photovoltaic off-grid according to claim 8, characterized in that: For calculating the current power supply capacity, the formula is used: Among them, W adjust,off,j represents the power supply of the switchable devices on bus j after adjustment, W off,j represents the original power supply of the switchable devices on bus j, W error,j represents the power supply error of bus j, ∑W off,j represents the total power supply of all switchable devices on bus j, ∑W intermittent,j represents the total power supply of all intermittently operating devices on bus j.

10. A power distribution system for off-grid photovoltaic applications, characterized in that, Executed according to the power distribution method for photovoltaic off-grid according to any one of claims 1-9, the system includes: The photovoltaic power fluctuation detection module obtains the input power of the photovoltaic module and calculates the instantaneous change rate, judges the change trend of the photovoltaic power, and records the current photovoltaic power level, obtaining the photovoltaic power change information; The load characteristic analysis and classification module analyzes the photovoltaic power level based on the photovoltaic power change information, obtains the instantaneous power demand, voltage adaptation range and operation mode of the off-grid power supply device, and classifies various types of power supply devices, obtaining the load power classification result; Based on the classification result of the load power, the power supply priority adjustment module calculates the total power demand of each type of off-grid power supply equipment, adjusts the power supply priority of each type of electrical equipment, and obtains the photovoltaic power supply adjustment result; Based on the photovoltaic power supply adjustment result, the hierarchical bus power supply management module connects the equipment to the DC bus of the corresponding voltage, calculates the total power demand of each type of DC bus and compares it with the available power of the current bus, adjusts the power supply connection mode of the equipment, and obtains the hierarchical bus power supply distribution information; The energy storage dynamic regulation module obtains the power supply status of each type of bus from the hierarchical bus power supply distribution information, and adjusts the charge and discharge of the energy storage equipment according to the change trend of the photovoltaic input power to obtain the photovoltaic off-grid power distribution result.

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