Multi-mode operation method and device of combined power supply system of diesel and battery and storage medium

Abstract

The application discloses a multi-mode operation method and device of a diesel storage combined power supply system and a storage medium, and relates to the technical field of power systems. The method comprises the following steps: collecting state parameters of a power distribution network system in real time; determining whether the current state of the power distribution network system meets a preset any operation mode switching condition according to the state parameters; if the operation mode switching condition is met, selecting one operation mode from a standby power source mode, a load balancing mode, a peak shaving mode, a fuel saving mode and a rapid power balancing mode based on the current state of the power distribution network system and load demand; and executing a coordinated control strategy corresponding to the selected operation mode to control the power output of a diesel generator set, an energy storage system and a photovoltaic system. The application solves the technical problem that, in the prior art, the state of an electric network is diversified and changeable, which leads to poor flexibility of power supply mode adjustment of the electric network and further affects the power supply stability of the power distribution network.

Description

Technical Field

[0001] This application relates to the field of power system technology, and more specifically, to a multi-mode operation method, apparatus, and storage medium for a combined diesel and energy storage power supply system. Background Technology

[0002] In traditional power distribution network security, diesel generator sets are widely used as reliable backup power sources to ensure the grid's continuous power supply capability under abnormal conditions. However, in certain scenarios, such as power supply security for major events, continuous power supply to important users, or uninterrupted power supply operations in the distribution network, relying solely on diesel generators can no longer meet the requirements of rapid response and economy. Especially after the large-scale integration of renewable energy sources, their volatility and intermittency may lead to power flow reversal or sudden load changes, potentially causing power backflow issues in distribution lines. Such sudden changes can not only cause significant fluctuations in supply voltage and frequency but also reduce the reliability and stability of the power supply from diesel generator sets.

[0003] Energy storage systems, due to their excellent power regulation characteristics and rapid response capabilities, can effectively cope with power fluctuations in the power grid. Therefore, combined diesel and energy storage power supply systems play an important role in power distribution network security, especially in situations with high penetration of new energy sources. However, current combined diesel and energy storage power supply systems have certain limitations in their operation modes, lacking the ability to flexibly adjust operating strategies according to the real-time status of the power grid, resulting in poor overall system reliability and economic efficiency.

[0004] There is currently no effective solution to the above problems. Summary of the Invention

[0005] This application provides a multi-mode operation method, apparatus, and storage medium for a combined diesel and energy storage power supply system, in order to at least solve the technical problem in the prior art where the power supply mode adjustment is inflexible due to the diverse and changeable nature of the power grid, which in turn affects the power supply stability of the distribution network.

[0006] According to one aspect of the embodiments of this application, a multi-mode operation method for a diesel-storage combined power supply system is provided, comprising: real-time acquisition of state parameters of the distribution network system, wherein the state parameters include at least grid voltage, load power, photovoltaic output power, and state of charge data of the energy storage system; determining, based on the state parameters, whether the current state of the distribution network system meets any preset operating mode switching condition; if the operating mode switching condition is met, selecting an operating mode from standby power supply mode, load balancing mode, peak shaving mode, fuel saving mode, and fast power balancing mode based on the current state and load demand of the distribution network system; and executing a coordinated control strategy corresponding to the selected operating mode to control the power output of the diesel generator set, energy storage system, and photovoltaic system.

[0007] Optionally, determining whether the current state of the distribution network system meets any preset operating mode switching condition includes: determining that the current state of the distribution network system meets the switching condition for the standby power supply mode when the grid voltage is detected to drop below a preset voltage threshold; determining that the current state of the distribution network system meets the switching condition for the load balancing mode when the load power is detected to be less than a preset low load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected or off-grid state; and determining that the current state of the distribution network system meets the switching condition for the load balancing mode when the load power is detected to be greater than a preset peak load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected state. In the following situations, the distribution network system is determined to meet the switching conditions for peak shaving mode; when the load power fluctuation rate is detected to be within the normal fluctuation rate range and the photovoltaic output power is less than the load power, and the distribution network system is currently in an off-grid state, the current state of the distribution network system is determined to meet the switching conditions for fuel saving mode; when the load power fluctuation rate is detected to exceed the normal fluctuation rate range or the photovoltaic output power changes abruptly, and the distribution network system is currently in an off-grid state, the distribution network system is determined to meet the switching conditions for fast power balance mode, wherein the photovoltaic output power change abruptly indicates that the absolute value of the change in photovoltaic output power is greater than a preset threshold.

[0008] Optionally, a coordinated control strategy corresponding to the backup power mode is implemented, including: controlling the energy storage system to immediately establish an islanded voltage using a constant voltage and constant frequency control mode after detecting a grid fault, and supplying power to the load; synchronously starting the diesel generator set to supply power, and after the output power of the diesel generator set reaches a stable state, gradually transferring the load power from the energy storage system to the diesel generator set through a dynamic power allocation algorithm; wherein, the constant voltage and constant frequency control mode is a grid-connected or islanded operation control mode that maintains the voltage and frequency reference of the distribution network system when there is no stable grid support by controlling the output AC voltage of the power electronic converter to be constant in both amplitude and frequency.

[0009] Optionally, a coordinated control strategy corresponding to the load balancing mode is implemented, including: controlling the energy storage system to adopt a virtual synchronous generator control strategy to dominate the power supply of the distribution network system; controlling the diesel generator set to operate in a low-power or no-load state, wherein the low-power operation state indicates that the output power of the diesel generator set does not exceed the preset power; and monitoring the state of charge data of the energy storage system in real time. If the state of charge data is detected to exceed the preset range, the diesel generator set is started to charge the energy storage system or the operation mode is adjusted.

[0010] Optionally, a coordinated control strategy corresponding to the peak shaving mode is implemented, including: controlling the diesel generator set to operate at a preset economic operating point power, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, the preset ratio being greater than 0 and less than or equal to 1; controlling the energy storage system to respond in real time to the power difference between the load power of the distribution network system and the output power of the diesel generator set, discharging to supplement the power difference; controlling the photovoltaic system to operate in a target photovoltaic power generation mode, and prioritizing the supply of the photovoltaic system's output power to the load, wherein the target photovoltaic power generation mode includes: the photovoltaic inverter or controller adjusting the operating point in real time so that the photovoltaic array always operates at the maximum power output point under the current environmental conditions such as light and temperature.

[0011] Optionally, a coordinated control strategy corresponding to the fuel-saving mode is implemented, including: controlling the diesel generator set to output power at a preset economic operating point, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, the preset ratio being greater than 0 and less than or equal to 1; comparing the load power of the distribution network system with the economic operating point power; if the load power of the distribution network system is less than the economic operating point power, controlling the energy storage system to absorb the excess power of the diesel generator set for charging; if the load power of the distribution network system is greater than the economic operating point power, controlling the energy storage system to discharge to make up for the power difference.

[0012] Optionally, the multi-mode operation method of the diesel-storage combined power supply system also includes: monitoring the state of charge data of the energy storage system; when the state of charge data of the energy storage system is detected to be less than the lower limit threshold of the target power range, forcibly starting the diesel generator set to charge the energy storage system; when the state of charge data of the energy storage system is detected to be greater than the upper limit threshold of the target power range, prioritizing the use of the energy storage system for power supply and reducing the output power of the diesel generator set.

[0013] Optionally, a control strategy corresponding to the fast power balance mode is executed, including: detecting whether the load power of the distribution network system at the current moment is greater than the photovoltaic output power; if the load power is detected to be greater than the photovoltaic output power, controlling the diesel generator set to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and controlling the energy storage system to adopt a target power control mode to compensate for the power difference between the load power and the target total output power, wherein the target total output power is equal to the sum of the photovoltaic output power and the output power of the diesel generator set, and the target power control mode includes: the power electronic converter in the energy storage system performs closed-loop control of the output active power and reactive power according to the received set value as an instruction; if the load power is detected to be less than or equal to the photovoltaic output power, controlling the diesel generator set to run under no-load, and controlling the photovoltaic system to output limited power through the target photovoltaic power generation mode, while controlling the energy storage system to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and absorbing the excess output power of the photovoltaic system.

[0014] Optionally, the energy storage system also includes an outer power prediction loop based on Kalman filtering to trigger control actions in advance when a sudden change in photovoltaic output is detected; and an inner power tracking loop based on model predictive control to achieve power tracking and detection.

[0015] According to another aspect of the embodiments of this application, a multi-mode operation device for a diesel-storage combined power supply system is also provided, comprising: an acquisition unit, configured to acquire state parameters of the distribution network system in real time, wherein the state parameters include at least grid voltage, load power, photovoltaic output power, and state of charge data of the energy storage system; a judgment unit, configured to determine whether the current state of the distribution network system meets any preset operation mode switching condition based on the state parameters; a first processing unit, configured to select an operation mode from a backup power mode, a load balancing mode, a peak shaving mode, a fuel saving mode, and a fast power balancing mode based on the current state and load demand of the distribution network system if the operation mode switching condition is met; and an execution unit, configured to execute a coordinated control strategy corresponding to the selected operation mode to control the power output of the diesel generator set, the energy storage system, and the photovoltaic system.

[0016] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, which stores a computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located executes the above-described multi-mode operation method of the diesel-storage combined power supply system.

[0017] According to another aspect of the embodiments of this application, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when one or more programs are executed by one or more processors, the one or more processors cause the one or more processors to execute the multi-mode operation method of the diesel-storage combined power supply system described above.

[0018] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program or instructions, which, when executed by a processor, implement the multi-mode operation method of the diesel-storage combined power supply system described above.

[0019] In this application, the multi-mode operation method of the diesel-storage combined power supply system first collects the status parameters of the distribution network system in real time. The status parameters include at least grid voltage, load power, photovoltaic output power, and the state of charge data of the energy storage system. Based on the status parameters, it is determined whether the current state of the distribution network system meets any preset operating mode switching condition. If the operating mode switching condition is met, an operating mode is selected from standby power mode, load balancing mode, peak shaving mode, fuel saving mode, and fast power balancing mode based on the current state of the distribution network system and load demand. The coordinated control strategy corresponding to the selected operating mode is executed to control the power output of the diesel generator set, energy storage system, and photovoltaic system.

[0020] In this embodiment of the application, through real-time monitoring and intelligent analysis, the diesel-storage combined power supply system can dynamically adjust the system's operating mode according to the real-time status of the power grid and load demand, thereby achieving flexible adjustment of the operating mode of the diesel-storage combined power supply system. This solves the technical problem in the prior art where the power grid's power supply mode adjustment is inflexible due to the diverse and changeable nature of the power grid's status, which in turn affects the power supply stability of the distribution network. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0022] Figure 1 This is a flowchart of an optional multi-mode operation method for a combined diesel and energy storage power supply system according to an embodiment of this application;

[0023] Figure 2 This is a flowchart illustrating an optional operation strategy mode switching method according to an embodiment of this application.

[0024] Figure 3 This is a diagram of an optional backup power mode control strategy according to an embodiment of this application;

[0025] Figure 4 This is a diagram of an optional load balancing mode control strategy according to an embodiment of this application;

[0026] Figure 5 This is a diagram of an optional peak clipping mode control strategy according to an embodiment of this application;

[0027] Figure 6 This is a diagram of an optional fuel-saving mode control strategy according to an embodiment of this application;

[0028] Figure 7 This is a diagram of an optional fast power balancing mode control strategy according to an embodiment of this application;

[0029] Figure 8 This is a schematic diagram of a multi-mode operation device for an optional diesel-storage combined power supply system according to an embodiment of this application. Detailed Implementation

[0030] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0031] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0032] According to an embodiment of this application, a method embodiment of a multi-mode operation method for a combined diesel and energy storage power supply system is provided. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Furthermore, although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0033] According to the embodiments of this application, a multi-mode operation system (hereinafter referred to as the system) of a diesel-storage combined power supply system can be used as the execution subject of the multi-mode operation method of the diesel-storage combined power supply system in the embodiments of this application. The multi-mode operation system of the diesel-storage combined power supply system can be a software system or an embedded system combining software and hardware. Of course, the execution subject of the method in the embodiments of this application can also be other forms of execution subject, such as devices, equipment, etc. It should be known by those skilled in the art that this application does not particularly limit the specific form of the execution subject of the method.

[0034] Figure 1 This is a flowchart of an optional multi-mode operation method for a combined diesel and energy storage power supply system according to an embodiment of this application, such as... Figure 1 As shown, the method includes the following steps:

[0035] Step S101: Real-time acquisition of the status parameters of the distribution network system, wherein the status parameters include at least grid voltage, load power, photovoltaic output power and the state of charge data of the energy storage system.

[0036] Optionally, real-time acquisition means that the system needs to continuously and quickly acquire various operating data of the power grid in order to make an immediate response; the status parameters include at least the grid voltage, load power, photovoltaic output power and the state of charge of the energy storage system, which represent the instantaneous health status of the power grid, the current power demand, the real-time supply of renewable energy and the energy reserve level of the energy storage device.

[0037] Optionally, real-time data acquisition allows the system to respond immediately to changes in the power grid, such as voltage fluctuations or load changes. Real-time data acquisition is crucial for maintaining power quality and preventing potential power system failures, especially in environments with high penetration of renewable energy sources. Instant data feedback mechanisms can control the negative impacts of uncertainties in photovoltaic output, contributing to system stability.

[0038] Step S102: Based on the status parameters, determine whether the current status of the distribution network system meets any preset operating mode switching condition.

[0039] Optionally, the operating mode switching conditions refer to a set of criteria that define when to switch from the current operating mode to another mode. These criteria are based on considerations of grid safety and economic operation, such as parameters like load fluctuations, changes in photovoltaic output, energy storage status, and grid frequency.

[0040] Optionally, the system analyzes the collected state parameters and compares them with preset mode switching conditions. For example, if the load suddenly increases and exceeds the upper limit of the diesel generator set's economical operation, the system will identify the need to switch to "peak shaving mode"; or, when photovoltaic output is excessive and energy storage is saturated, the system will switch to "fuel saving mode". Through these operations, the system can intelligently select the operating mode according to the actual needs and resource conditions of the power grid, reducing the rigid control of traditional modes and improving the system's operating efficiency and economy.

[0041] Step S103: If the operating mode switching conditions are met, then based on the current state of the distribution network system and the load demand, select one operating mode from the backup power supply mode, load balancing mode, peak shaving mode, fuel saving mode and fast power balancing mode.

[0042] Optionally, each operating mode corresponds to different grid operating conditions and control objectives. For example, the "backup power mode" aims to quickly restore power supply, while the "peak shaving mode" focuses on mitigating load peaks.

[0043] Optionally, when a signal that meets the mode switching conditions is detected, the system will calculate the fitness score of each mode for the current situation, and then select the operating mode with the highest score for switching. For example, the "load balancing mode" is suitable for periods with low load and limited photovoltaic output. At this time, the energy storage system can provide the main power support, reducing the operation of diesel generator sets and achieving energy saving.

[0044] Optionally, by accurately matching the operating mode, the system can maximize the use of existing resources, improve energy efficiency, reduce fuel consumption, and maintain the continuity and reliability of power supply from the grid.

[0045] Step S104: Execute the coordinated control strategy corresponding to the selected operating mode to control the power output of the diesel generator set, energy storage system and photovoltaic system.

[0046] Optionally, the coordinated control strategy is used to schedule the output of resources such as diesel generator sets, energy storage, and photovoltaics to adapt to the requirements of selected operating modes, such as diesel generator set output optimization and energy storage charging and discharging management under the "fuel saving mode".

[0047] Optionally, once the system selects an operating mode, the corresponding control strategy will be activated. For example, in "fuel-saving mode," the diesel generator set will be controlled near the optimal economic operating point (approximately 80% of rated power), while the energy storage system will adjust its charging and discharging behavior according to load demand, thereby achieving fuel savings and economical system operation.

[0048] Optionally, implementing coordinated control strategies can improve the system's economic efficiency and environmental friendliness, while also contributing to the security and quality of power supply. Through this dynamic adjustment, the system can better cope with the challenges of the volatility and intermittency of new energy sources, maintaining the stable operation of the power grid.

[0049] In one optional embodiment, determining whether the current state of the distribution network system meets any preset operating mode switching condition includes: determining that the current state of the distribution network system meets the switching condition for the standby power supply mode when the grid voltage is detected to drop below a preset voltage threshold; determining that the current state of the distribution network system meets the switching condition for the load balancing mode when the load power is detected to be less than a preset low load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected or off-grid state; and determining that the current state of the distribution network system meets the switching condition for the load balancing mode when the load power is detected to be greater than a preset peak load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected or off-grid state. Under the condition of being in grid-connected status, the distribution network system is determined to meet the switching conditions for peak shaving mode. When the load power fluctuation rate is detected to be within the normal fluctuation rate range and the photovoltaic output power is less than the load power, and the distribution network system is currently in an off-grid state, the current state of the distribution network system is determined to meet the switching conditions for fuel saving mode. When the load power fluctuation rate is detected to exceed the normal fluctuation rate range or the photovoltaic output power undergoes a sudden change, and the distribution network system is currently in an off-grid state, the distribution network system is determined to meet the switching conditions for fast power balance mode. Among these conditions, a sudden change in photovoltaic output power indicates that the absolute value of the change in photovoltaic output power is greater than a preset threshold.

[0050] Optionally, the system continuously monitors the grid voltage level using voltage sensors. Once the grid voltage drops below a set threshold, the system considers the current state to meet the switching conditions for the backup power mode. At this point, the system immediately activates the diesel-energy storage combined power supply system. The energy storage system initially provides power for a short period, followed by the diesel generator gradually connecting to the grid until a stable power supply is achieved. Through these steps, the system can respond quickly to grid faults, thus contributing to the continuous power supply of critical loads and reducing momentary interruptions caused by grid voltage drops.

[0051] Optionally, load power refers to the total electrical power consumed by all connected loads in the current distribution network system.

[0052] Alternatively, photovoltaic output power is the electrical power that a solar photovoltaic panel can provide under current conditions.

[0053] Optionally, the low load threshold is a power threshold used to determine whether the system is in a low load state; a value below this threshold indicates that the system load is low.

[0054] Optionally, when the system detects that the load power is lower than a preset low load threshold and the photovoltaic output power is insufficient to meet the load demand, and considering the current grid-connected or off-grid status of the distribution network system, the system will determine that the current state meets the switching conditions for the load balancing mode. In the load balancing mode, the energy storage system is mainly responsible for power supply, while the diesel generator maintains low-power operation or an unloaded state. The purpose is to reduce the use of diesel generators when the load is low, improve energy utilization efficiency, and reduce operating costs.

[0055] Optionally, the peak load threshold is used to identify the power threshold of peak load conditions. When the load power is higher than this threshold, the system will face higher power supply demands.

[0056] Optionally, when the system detects that the load power exceeds the peak load threshold, while the photovoltaic output power is still less than the power required by the load, and the system is in grid-connected status, it determines that the current state is suitable for switching to peak shaving mode. In peak shaving mode, the diesel generator set will operate at near full load power, while the energy storage system will quickly respond to load fluctuations and fill the supply-demand gap. The purpose is to coordinate the diesel generator set and the energy storage system to jointly cope with the demand during peak load periods, reduce the burden on the diesel generator set, and avoid overload.

[0057] Optionally, when the system is in an off-grid state, and the detected load power fluctuation rate is within the normal fluctuation range, while the photovoltaic output is still less than the load power, the system determines that the current state is suitable for fuel-saving mode. In fuel-saving mode, the diesel generator set will maintain operation at the most economical power output level, while the energy storage system will adjust its charging and discharging according to subtle changes in the load to optimize the utilization of the diesel generator set's power, thereby saving fuel as much as possible and improving operational economy while ensuring stable power supply.

[0058] Optionally, when the system is operating off-grid and detects a sudden increase in load power fluctuation beyond the normal fluctuation range, or a sudden change in photovoltaic output exceeding a preset threshold, the system determines that the current state needs to switch to a fast power balance mode. In fast power balance mode, the energy storage system is allowed to respond quickly, smoothing power fluctuations and reducing system voltage and frequency instability. Simultaneously, the diesel generator set provides base power or acts as a backup when necessary to maintain system balance. Its core objective is to help the system react quickly to extreme load changes or sudden changes in photovoltaic supply, maintaining voltage and frequency stability, reducing reverse power protection actions, and thus achieving stable system operation.

[0059] Figure 2 This is a flowchart illustrating an optional operation strategy mode switching method according to an embodiment of this application. For example... Figure 2 As shown, the switching conditions for the combined diesel and energy storage operation mode include: system grid connection status, load status, and photovoltaic status.

[0060] When the system meets the requirements of off-grid operation, normal load changes, and normal and fluctuating photovoltaic output at the grid connection point, it switches to standby power mode. At this time, the operating status of the diesel generator set and the energy storage system is: diesel generator set in standby mode, and energy storage system in standby mode.

[0061] When the system meets the requirements of grid-connected / off-grid operation, normal load change and low-power operation, and normal photovoltaic output at the grid connection point is less than the load, and normal photovoltaic output fluctuates, it switches to load balancing mode. At this time, the operating status of the diesel generator set and the energy storage system is: the diesel generator set operates at low power, and the energy storage system operates with dynamic power change.

[0062] When the system meets the requirements of grid-connected operation, normal load change and high load peak operation, and normal output of photovoltaic power at the grid connection point which is less than the load and normal output fluctuation of photovoltaic power, it switches to peak shaving mode. At this time, the operating status of diesel generator set and energy storage system is: diesel generator set operates at rated power and energy storage system operates at peak shaving.

[0063] When the system meets the requirements of off-grid operation, normal load changes, and normal output of photovoltaic power at the grid connection point that is less than the load, and normal output of photovoltaic power fluctuates, the system switches to fuel-saving mode. At this time, the operating status of the diesel generator set and the energy storage system is as follows: the diesel generator set operates at its optimal power, and the energy storage system dynamically adjusts its power.

[0064] When the system meets the conditions of off-grid operation, sudden load change, and large photovoltaic power generation at the grid connection point with smaller load, resulting in power output exceeding the load and power backfeed, it switches to the fast power smoothing mode. At this time, the operating status of the diesel generator set and the energy storage system is as follows: the diesel generator set operates under no-load conditions, and the energy storage system operates with rapid power adjustment.

[0065] In one optional embodiment, a coordinated control strategy corresponding to the backup power mode is executed, including: controlling the energy storage system to immediately establish an islanded voltage using a constant voltage and constant frequency control mode after detecting a grid fault, and supplying power to the load; synchronously starting the diesel generator set to supply power, and after the output power of the diesel generator set reaches a stable state, gradually transferring the load power from the energy storage system to the diesel generator set through a dynamic power allocation algorithm; wherein, the constant voltage and constant frequency control mode is a grid-connected or islanded operation control mode that maintains the voltage and frequency reference of the distribution network system when there is no stable grid support by controlling the output AC voltage of the power electronic converter to be constant in both amplitude and frequency.

[0066] Optionally, upon detecting a drop in grid voltage below a preset voltage threshold, i.e., a grid fault, the system immediately initiates an emergency response procedure. The energy storage system, acting as a rapid response unit within the system, will switch to constant voltage and frequency control mode within milliseconds, quickly generating a stable AC voltage signal to establish a voltage reference for the isolated grid and provide initial power supply to the load. The constant voltage and frequency mode, through precise control of power electronic converters (such as inverters), maintains the output AC voltage amplitude and frequency at predetermined reference values. Even in the event of grid synchronization failure, it can maintain voltage and frequency stability in the distribution network, contributing to power supply continuity.

[0067] Optionally, the system will then synchronously start the diesel generator set. Since diesel generators have a slow start-up response, typically requiring several seconds to tens of seconds to reach a stable power output, the energy storage system will assume the primary power supply task at this time. The energy storage system will continuously provide the necessary electrical energy until the diesel generator set reaches a stable power output, helping to ensure that the stability of the power grid and the quality of power supply are not affected during the transition period.

[0068] Optionally, after the output power of the diesel generator set stabilizes, the system will gradually transfer the load from the energy storage system to the diesel generator set through a dynamic power allocation algorithm, thereby balancing the power output of the energy storage and the diesel generator and reducing resource waste or equipment damage caused by over-reliance on one party.

[0069] Optionally, the dynamic power allocation algorithm automatically adjusts the power transfer ratio between the diesel generator and the energy storage system based on real-time monitored load power, the state of charge of the energy storage system, and the operating status of the diesel generator, ultimately achieving a dynamic balance with the diesel generator as the primary power source and energy storage as the auxiliary power source. Throughout the process, the active power output of the energy storage system will gradually decrease as the power supply from the diesel generator increases, but it will not completely stop working, in preparation for unforeseen circumstances. Through a state machine-based power transfer strategy, the system can achieve seamless switching between the diesel generator and energy storage, contributing to power supply continuity while also optimizing resource utilization.

[0070] Figure 3 This is a diagram illustrating an optional backup power mode control strategy according to an embodiment of this application. For example... Figure 3 As shown, when the system detects that the grid voltage has dropped to 0, it enters the standby power mode, and the energy storage system starts the grid-connected constant voltage and constant frequency mode. At this time, the starting power of the diesel generator set increases when connected to the grid, while the power of the energy storage system decreases, and the energy storage system and the diesel generator set operate jointly off-grid.

[0071] In one optional embodiment, a coordinated control strategy corresponding to the load balancing mode is executed, including: controlling the energy storage system to adopt a virtual synchronous generator control strategy to dominate the power supply of the distribution network system; controlling the diesel generator set to operate in a low-power or no-load state, wherein the low-power operating state indicates that the output power of the diesel generator set does not exceed a preset power; and monitoring the state of charge data of the energy storage system in real time. If the state of charge data is detected to exceed a preset range, the diesel generator set is started to charge the energy storage system or the operating mode is adjusted.

[0072] Optionally, in load balancing mode, the energy storage system plays a role similar to a traditional synchronous generator, actively participating in the control of grid frequency and voltage by simulating the electrical characteristics of a synchronous generator. The virtual synchronous generator control strategy helps the energy storage system exchange energy with the grid like a real synchronous generator, maintaining grid stability.

[0073] Specifically, the energy storage system outputs an AC voltage with a frequency close to that of the power grid through a built-in power electronic converter. When the load changes, it can quickly adjust the output power and participate in frequency regulation, thereby dominating the power supply of the distribution network system.

[0074] Optionally, when the load on the power distribution network is low, the diesel generator set will be controlled to operate at low power, meaning that the output power is far lower than the rated power, and may even be in an unloaded state.

[0075] Optionally, the preset power refers to an upper limit of power set according to the economic operating range of the diesel generator set, generally set between 70-80% of the rated power, which helps to reduce unnecessary fuel consumption and extend engine life. Under low-load operating conditions, the diesel engine operates at low power or idling, which can reduce machine wear and fuel waste and improve the system's economy.

[0076] Optionally, the state of charge (SOC) refers to the ratio of the electrical energy currently stored in the energy storage system to its maximum storage capacity, and is an important indicator for measuring the usable energy of the energy storage system. The system monitors the SOC data of the energy storage system in real time through its built-in battery management system, helping to maintain the SOC data within a reasonable range, typically 30%-90%, thus ensuring sufficient charge and discharge capacity to prevent battery damage caused by overcharging and discharging. Once the SOC is detected to exceed the preset dynamic operating range, the control system will respond immediately, with the specific response steps as follows:

[0077] If the state of charge is below the preset lower limit (e.g., 30%), it indicates that the energy storage capacity is insufficient. At this time, the system will start the diesel generator set to charge the energy storage system to restore the power supply capacity.

[0078] If the state of charge is close to or exceeds the preset upper limit (e.g., 90%), it means that the energy storage system is close to full charge. In order to avoid overcharging, the system needs to adjust its operating mode, such as switching to other modes, to utilize the excess electrical energy.

[0079] Figure 4 This is an optional load balancing mode control strategy diagram according to an embodiment of this application. For example... Figure 4 As shown, when the system detects that the load is less than the set value and the time is greater than 3 minutes, it enters the load balancing mode. At this time, the diesel generator set power is reduced to standby mode, the energy storage system power is increased, and the energy storage system adjusts the power change operation.

[0080] In one optional embodiment, a coordinated control strategy corresponding to the peak shaving mode is executed, including: controlling the diesel generator set to operate at a preset economic operating point power, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, the preset ratio being greater than 0 and less than or equal to 1; controlling the energy storage system to respond in real time to the power difference between the load power of the distribution network system and the output power of the diesel generator set, discharging to supplement the power difference; controlling the photovoltaic system to operate in a target photovoltaic power generation mode, and prioritizing the supply of the photovoltaic system's output power to the load, wherein the target photovoltaic power generation mode includes: the photovoltaic inverter or controller adjusting the operating point in real time so that the photovoltaic array always operates at the maximum power output point under the current environmental conditions such as light and temperature.

[0081] Optionally, the system sets the diesel generator set to operate at its economic operating point power, where the power level is the product of the generator set's rated power and its optimal economic operating ratio. The economic operating point power is selected based on the diesel generator's efficiency curve, typically set between 90% and 100% of the generator set's rated power, as this range results in the highest operating efficiency and lowest fuel consumption. Accurate control of the diesel generator set's operating status helps to meet high power output demands during peak load periods while maintaining good economy and energy-saving / emission-reduction effects.

[0082] Optionally, the system then monitors the difference between the load power of the distribution network and the output power of the diesel generator set in real time. If the difference exceeds a preset range, i.e., the current load demand exceeds the actual output of the diesel generator set, the energy storage system will respond immediately by discharging to make up for the power difference. Through a rapid response mechanism based on the collaborative work of the energy storage system's built-in battery management system and central processing unit, the system quickly adjusts power distribution by analyzing load demand and diesel generator set output in real time to smooth load fluctuations and contribute to stable power supply.

[0083] Optionally, in peak shaving mode, the photovoltaic system will be set to operate in the target photovoltaic power generation mode. This means that the operating point is adjusted in real time via the photovoltaic inverter or controller to ensure the photovoltaic array always operates at its maximum power point under the current environmental conditions, such as sunlight and temperature. The photovoltaic system prioritizes supplying power to the load, maximizing the utilization of renewable energy through maximum power point tracking technology, further improving the system's economic efficiency and environmental friendliness. Excess power from the photovoltaic system will also be optimized and stored in the energy storage system, achieving efficient energy utilization and balanced energy distribution.

[0084] Figure 5 This is a diagram illustrating an optional peak-shaving mode control strategy according to an embodiment of this application. For example... Figure 5 As shown, when the system is connected to the grid and the load is detected to be greater than the set value for more than 3 minutes, it enters the peak shaving mode. At this time, the power of the diesel generator set increases to more than 90% of the main load, the power of the energy storage system decreases and real-time power adjustment is implemented, and the energy storage system dominates the adjustment of peak power changes.

[0085] In one optional embodiment, a coordinated control strategy corresponding to the fuel-saving mode is executed, including: controlling the diesel generator set to output power at a preset economic operating point, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, the preset ratio being greater than 0 and less than or equal to 1; comparing the load power of the distribution network system with the economic operating point power; if the load power of the distribution network system is less than the economic operating point power, controlling the energy storage system to absorb excess power from the diesel generator set for charging; if the load power of the distribution network system is greater than the economic operating point power, controlling the energy storage system to discharge to make up for the power difference.

[0086] Optionally, the system first controls the output power of the diesel generator set through a pre-set economic operating point. Secondly, it continuously monitors the actual load demand of the distribution network and compares it with the economic operating point power of the diesel generator set. The real-time monitoring and comparison process is performed by the central processing unit, which receives data from load monitoring and the diesel generator set's output power, and uses internal algorithms to quickly analyze the relationship between the two to determine whether the diesel generator set's power meets the current load demand.

[0087] Optionally, the system will adopt different charging and discharging control strategies for the energy storage system based on the difference between the load power and the economic operating point power of the diesel generator set. If the load power of the distribution network system is less than the economic operating point power of the diesel generator set, the system will control the energy storage system to absorb the excess output power of the diesel generator set for charging, thereby reducing the waste of diesel generator set power and converting the surplus energy into electrical energy reserves for the energy storage system, improving the overall energy utilization efficiency of the system. Conversely, if the load power is greater than the economic operating point power, the system will command the energy storage system to discharge to make up for the power difference. Through the discharge operation, the energy released by the energy storage system can meet the grid load demand in a timely manner and maintain the stable operation of the system without affecting the economic operation of the diesel generator set.

[0088] Figure 6 This is a diagram illustrating an optional fuel-saving mode control strategy according to an embodiment of this application. For example... Figure 6 As shown, when operating off-grid and detecting normal load changes, the system enters fuel-saving mode. At this time, the diesel generator set always operates at 80% of its rated power, and the energy storage system performs real-time power adjustment to meet load demands.

[0089] In one optional embodiment, the multi-mode operation method of the diesel-storage combined power supply system further includes: monitoring the state of charge data of the energy storage system; when the state of charge data of the energy storage system is detected to be less than the lower limit threshold of the target power range, forcibly starting the diesel generator set to charge the energy storage system; when the state of charge data of the energy storage system is detected to be greater than the upper limit threshold of the target power range, prioritizing the use of the energy storage system for power supply and reducing the output power of the diesel generator set.

[0090] Optionally, the system is equipped with an advanced battery management system for continuous monitoring of the energy storage device's state of charge (SOC) data. Continuous tracking of SOC data helps the energy storage system avoid both over-discharging and over-charging, maintaining a healthy operating state over the long term.

[0091] Optionally, when the state of charge (SOC) data falls below the lower threshold of the target SOC range, a forced charging strategy will be implemented. The target SOC range is the recommended SOC range for healthy and effective operation of the energy storage system, typically between 30% and 90%. When the lower threshold is reached, indicating that the energy storage capacity of the energy storage device has dropped below a critical point, the system will automatically start the diesel generator set to charge the energy storage system until the SOC returns to the target range. These measures prevent the energy storage system from failing to respond promptly to power demands due to low SOC, contributing to the system's continuous operation and stability.

[0092] Optionally, when the state of charge (SBC) data exceeds the upper limit threshold of the target energy range, an optimized power supply strategy will be adopted. If the SBC of the energy storage system exceeds the preset upper limit threshold, it means that the energy storage device is close to saturation. At this time, the system will prioritize using the energy storage system for power supply, while reducing the output power of the diesel generator set to reduce unnecessary energy waste and safety hazards caused by overcharging. The optimized power supply strategy allows the energy storage system to maximize its electrical energy utilization when the load is low or the photovoltaic output is sufficient, while the diesel generator set reduces its operating level, saves fuel consumption, and achieves optimized energy allocation.

[0093] In one optional embodiment, a control strategy corresponding to the fast power balance mode is executed, including: detecting whether the load power of the distribution network system at the current moment is greater than the photovoltaic output power; if the load power is detected to be greater than the photovoltaic output power, controlling the diesel generator set to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and controlling the energy storage system to adopt a target power control mode to compensate for the power difference between the load power and the target total output power, wherein the target total output power is equal to the sum of the photovoltaic output power and the output power of the diesel generator set, and the target power control mode includes: the power electronic converter in the energy storage system performs closed-loop control on the output active power and reactive power according to the received set value as an instruction; if the load power is detected to be less than or equal to the photovoltaic output power, controlling the diesel generator set to run under no-load, and controlling the photovoltaic system to output limited power through the target photovoltaic power generation mode, while controlling the energy storage system to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and absorbing the excess output power of the photovoltaic system.

[0094] Optionally, the system is equipped with real-time monitoring equipment that can continuously collect load data from the power distribution network and output data from the photovoltaic system. This real-time monitoring function allows the system to instantly understand current electricity demand and the energy supply status of the photovoltaic system, providing a basis for subsequent decision-making.

[0095] Optionally, when the system detects a sudden increase in load power exceeding the real-time output of the photovoltaic system, the system will immediately take action, starting the diesel generator set through constant voltage and frequency control. This helps maintain the voltage and frequency of the distribution network system at a safe and stable level. Simultaneously, the energy storage system will adopt a target power control mode. That is, the power electronic converter in the energy storage system performs closed-loop control on the output active and reactive power according to the received setpoint commands to compensate for the power difference between the load power and the target total output power. The target total output power refers to the sum of the photovoltaic output power and the diesel generator set output power at the current moment. The implementation of the closed-loop control strategy allows the energy storage system to respond accurately and quickly to power shortages, contributing to the stable operation of the distribution network.

[0096] Optionally, if the system detects a decrease in load power or sufficient photovoltaic output, such that the load power is less than or equal to the photovoltaic output power, the diesel generator set will operate under no-load conditions, while the photovoltaic system will limit its output through the target photovoltaic power generation mode. In this state, the photovoltaic array always operates near its maximum power point under current environmental conditions such as sunlight and temperature, but does not exceed load demand, reducing backfeed power. Simultaneously, the energy storage system employs a constant voltage and frequency control mode to maintain the voltage and frequency stability of the distribution network system, while absorbing excess output power from the photovoltaic system, thereby reducing energy waste and improving the overall energy efficiency of the system.

[0097] Figure 7 This is a diagram illustrating an optional fast power balancing mode control strategy according to an embodiment of this application. For example... Figure 7 As shown, when operating off-grid and detecting a load change exceeding 30% of the system's rated load within 30 seconds, the system enters a rapid power balancing mode. At this time, the diesel generator set reduces its power to no-load operation, and the energy storage system rapidly adjusts its power in real time, quickly adapting to power changes.

[0098] In one alternative embodiment, the energy storage system also includes an outer power prediction loop based on Kalman filtering to trigger control actions in advance when a sudden change in photovoltaic output is detected; and an inner power tracking loop based on model predictive control to achieve power tracking and detection.

[0099] Optionally, in this application, the energy storage system utilizes Kalman filtering technology to predict the external input, i.e., photovoltaic power output, in real time. The main purpose is to detect changes in photovoltaic power output in advance. Once a sudden change in photovoltaic power output is detected (e.g., a sharp drop in power due to cloud cover), the system can react immediately and trigger control actions in advance. This means that the energy storage system can adjust its own charging and discharging state before changes in photovoltaic output power occur, preparing to cope with upcoming power fluctuations. This contributes to the stability of the system voltage frequency and reduces system instability caused by sudden changes in photovoltaic power output.

[0100] Optionally, model predictive control (MMCC) predicts and optimizes the output for several future time steps based on a system dynamics model. In the inner control loop of the energy storage system, MMCC is used to track and detect power. The main task of the inner loop is to enable the energy storage system to respond quickly and accurately track the power required by the system. Through MMCC algorithms, the energy storage system can adjust its charging and discharging strategies in real time based on the current system state and the predicted load demand over a period of time, compensating for power differences in the optimal way. Simultaneously, considering its own state of charge and charging / discharging capacity limitations, it reduces the performance degradation of energy storage devices caused by overcharging and discharging. This helps the energy storage system respond to load changes most efficiently and maintain stable system operation in a fast power balancing mode.

[0101] Figure 8 This is a schematic diagram of an optional multi-mode operation device for a combined diesel and energy storage power supply system according to an embodiment of this application. According to another aspect of an embodiment of this application, a multi-mode operation device for a combined diesel and energy storage power supply system is also provided, including: an acquisition unit 801, a judgment unit 802, a first processing unit 803, and an execution unit 804.

[0102] The system includes: an acquisition unit 801 for real-time acquisition of state parameters of the distribution network system, including at least grid voltage, load power, photovoltaic output power, and state of charge data of the energy storage system; a judgment unit 802 for determining whether the current state of the distribution network system meets any preset operating mode switching condition based on the state parameters; a first processing unit 803 for selecting an operating mode from standby power mode, load balancing mode, peak shaving mode, fuel saving mode, and fast power balancing mode based on the current state and load demand of the distribution network system if the operating mode switching condition is met; and an execution unit 804 for executing a coordinated control strategy corresponding to the selected operating mode to control the power output of the diesel generator set, energy storage system, and photovoltaic system.

[0103] Optionally, the judgment unit 802 includes: a first judgment subunit, configured to determine that the current state of the distribution network system meets the switching conditions for the standby power supply mode when the grid voltage is detected to drop below a preset voltage threshold; a second judgment subunit, configured to determine that the current state of the distribution network system meets the switching conditions for the load balancing mode when the load power is detected to be less than a preset low load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected or off-grid state; and a third judgment subunit, configured to determine that the current state of the distribution network system meets the switching conditions for the load balancing mode when the load power is detected to be greater than a preset peak load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected state. The distribution network system meets the switching conditions for peak shaving mode; the fourth judgment subunit is used to determine that the current state of the distribution network system meets the switching conditions for fuel saving mode when the load power fluctuation rate is within the normal fluctuation rate range and the photovoltaic output power is less than the load power, and the distribution network system is currently in an off-grid state; the fifth judgment subunit is used to determine that the distribution network system meets the switching conditions for fast power balance mode when the load power fluctuation rate exceeds the normal fluctuation rate range or the photovoltaic output power changes abruptly, and the distribution network system is currently in an off-grid state. Among them, the photovoltaic output power change abruptly indicates that the absolute value of the change in photovoltaic output power is greater than a preset threshold.

[0104] Optionally, the execution unit 804 includes: a first control subunit, used to control the energy storage system to immediately establish an islanded voltage using a constant voltage and constant frequency control mode after detecting a grid fault, and to supply power to the load; synchronously start the diesel generator set to supply power, and after the output power of the diesel generator set reaches a stable state, gradually transfer the load power from the energy storage system to the diesel generator set through a dynamic power distribution algorithm; wherein, the constant voltage and constant frequency control mode is a grid-connected or islanded operation control mode that maintains the voltage and frequency reference of the distribution network system when there is no stable grid support by controlling the output AC voltage of the power electronic converter with constant amplitude and frequency.

[0105] Optionally, the execution unit 804 further includes: a second control subunit for controlling the energy storage system to adopt a virtual synchronous generator control strategy to dominate the power supply of the distribution network system; a third control subunit for controlling the diesel generator set to operate in a low-power or no-load state, wherein the low-power operating state indicates that the output power of the diesel generator set does not exceed the preset power; and a monitoring subunit for real-time monitoring of the state of charge data of the energy storage system, and if the state of charge data is detected to exceed the preset range, starting the diesel generator set to charge the energy storage system or adjusting the operating mode.

[0106] Optionally, the execution unit 804 further includes: a fourth control subunit for controlling the diesel generator set to operate at a preset economic operating point power, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, and the preset ratio is greater than 0 and less than or equal to 1; a fifth control subunit for controlling the energy storage system to respond in real time to the power difference between the load power of the distribution network system and the output power of the diesel generator set, and to discharge to make up for the power difference; and a sixth control subunit for controlling the photovoltaic system to operate in a target photovoltaic power generation mode and prioritizing the supply of the photovoltaic system's output power to the load, wherein the target photovoltaic power generation mode includes: the photovoltaic inverter or controller adjusting the operating point in real time so that the photovoltaic array always operates at the maximum power output point under the current environmental conditions such as light and temperature.

[0107] Optionally, the execution unit 804 further includes: a seventh control subunit for controlling the diesel generator set to output power at a preset economic operating point, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, and the preset ratio is greater than 0 and less than or equal to 1; a comparison subunit for comparing the load power of the distribution network system with the economic operating point power; a first processing subunit for controlling the energy storage system to absorb excess power from the diesel generator set for charging if the load power of the distribution network system is less than the economic operating point power; and a second processing subunit for controlling the energy storage system to discharge to compensate for the power difference if the load power of the distribution network system is greater than the economic operating point power.

[0108] Optionally, the multi-mode operation device of the diesel-storage combined power supply system further includes: a monitoring unit for monitoring the state of charge data of the energy storage system; a second processing unit for forcibly starting the diesel generator set to charge the energy storage system when the detected state of charge data of the energy storage system is less than the lower limit threshold of the target power range; and a third processing unit for prioritizing the use of the energy storage system for power supply and reducing the output power of the diesel generator set when the detected state of charge data of the energy storage system is greater than the upper limit threshold of the target power range.

[0109] Optionally, the execution unit 804 further includes: a detection subunit, used to detect whether the load power of the distribution network system at the current moment is greater than the photovoltaic output power; a first detection and processing subunit, used to, if the load power is detected to be greater than the photovoltaic output power, control the diesel generator set to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and control the energy storage system to adopt a target power control mode to compensate for the power difference between the load power and the target total output power, wherein the target total output power is equal to the sum of the photovoltaic output power and the output power of the diesel generator set, and the target power control mode includes: the power electronic converter in the energy storage system uses the received set value as an instruction to perform closed-loop control on the output active power and reactive power; a second detection and processing subunit, used to, if the load power is detected to be less than or equal to the photovoltaic output power, control the diesel generator set to run under no-load, and control the photovoltaic system to output limited power through the target photovoltaic power generation mode, while controlling the energy storage system to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, and simultaneously absorb the excess output power of the photovoltaic system.

[0110] Optionally, the energy storage system also includes an outer power prediction loop based on Kalman filtering to trigger control actions in advance when a sudden change in photovoltaic output is detected; and an inner power tracking loop based on model predictive control to achieve power tracking and detection.

[0111] According to another aspect of the embodiments of this application, a computer-readable storage medium is also provided, which stores a computer program, wherein when the computer program is executed, the device where the computer-readable storage medium is located executes the above-described multi-mode operation method of the diesel-storage combined power supply system.

[0112] According to another aspect of the embodiments of this application, an electronic device is also provided, including one or more processors and a memory, the memory being used to store one or more programs, wherein when one or more programs are executed by one or more processors, the one or more processors cause the one or more processors to execute the multi-mode operation method of the diesel-storage combined power supply system described above.

[0113] According to another aspect of the embodiments of this application, a computer program product is also provided, including a computer program or instructions, which, when executed by a processor, implement the multi-mode operation method of the diesel-storage combined power supply system described above.

[0114] The sequence numbers of the embodiments in this application are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0115] In the above embodiments of this application, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions of other embodiments.

[0116] In the several embodiments provided in this application, it should be understood that the disclosed technical content can be implemented in other ways. The device embodiments described above are merely illustrative; for example, the division of units can be a logical functional division, and in actual implementation, there may be other division methods. For instance, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Furthermore, the displayed or discussed mutual coupling, direct coupling, or communication connection may be through some interfaces; the indirect coupling or communication connection between units or modules may be electrical or other forms.

[0117] The units described as separate components may or may not be physically separate. The components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the units can be selected to achieve the purpose of this embodiment according to actual needs.

[0118] Furthermore, the functional units in the various embodiments of this application can be integrated into one processing unit, or each unit can exist physically separately, or two or more units can be integrated into one unit. The integrated unit can be implemented in hardware or as a software functional unit.

[0119] If the integrated unit is implemented as a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or all or part of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, read-only memory (ROM), random access memory (RAM), portable hard drive, magnetic disk, or optical disk.

[0120] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A multi-mode operation method for a combined diesel and energy storage power supply system, characterized in that, include: The status parameters of the power distribution network system are collected in real time, wherein the status parameters include at least grid voltage, load power, photovoltaic output power and state of charge data of energy storage system; Based on the state parameters, determine whether the current state of the power distribution network system meets any preset operating mode switching condition; If the conditions for switching operating modes are met, then based on the current state and load demand of the power distribution network system, one operating mode is selected from the backup power supply mode, load balancing mode, peak shaving mode, fuel saving mode, and fast power balancing mode. Implement coordinated control strategies corresponding to the selected operating mode to control the power output of the diesel generator set, energy storage system, and photovoltaic system.

2. The method according to claim 1, characterized in that, Determining whether the current state of the distribution network system meets any preset operating mode switching condition includes: If the grid voltage is detected to drop below a preset voltage threshold, it is determined that the current state of the distribution network system meets the switching conditions for the backup power mode. If the load power is detected to be less than the preset low load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in a grid-connected or off-grid state, it is determined that the current state of the distribution network system meets the switching conditions of the load balance mode. If the load power is detected to be greater than the preset peak load threshold and the photovoltaic output power is less than the load power, and the distribution network system is currently in grid-connected state, it is determined that the distribution network system meets the switching conditions of the peak shaving mode. If the fluctuation rate of the load power is detected to be within the normal fluctuation range and the photovoltaic output power is less than the load power, and the distribution network system is currently in an off-grid state, it is determined that the current state of the distribution network system meets the switching conditions for the fuel saving mode. If the fluctuation rate of the load power exceeds the normal fluctuation range or the photovoltaic output power changes abruptly, and the distribution network system is currently in an off-grid state, it is determined that the distribution network system meets the switching conditions for the fast power balance mode. The abrupt change in photovoltaic output power indicates that the absolute value of the change in photovoltaic output power is greater than a preset threshold.

3. The method according to claim 1, characterized in that, Execute a coordinated control strategy corresponding to the backup power mode, including: Upon detecting a grid fault, the energy storage system immediately establishes an islanded grid voltage using a constant voltage and constant frequency control mode to supply power to the load; simultaneously, the diesel generator set is started to supply power. After the output power of the diesel generator set reaches a stable state, the load power is gradually transferred from the energy storage system to the diesel generator set through a dynamic power allocation algorithm. The constant voltage and constant frequency control mode is a grid-connected or islanded operation control method that maintains the voltage and frequency reference of the distribution network system when there is no stable power grid support by controlling the output AC voltage of the power electronic converter to be constant in both amplitude and frequency.

4. The method according to claim 1, characterized in that, Implement a coordinated control strategy corresponding to the load balancing mode, including: The energy storage system is controlled by a virtual synchronous generator control strategy, which dominates the power supply of the power distribution network system. The diesel generator set is controlled to operate in a low-power or no-load state, wherein the low-power operation state indicates that the output power of the diesel generator set does not exceed a preset power. The system monitors the state of charge (SOC) data of the energy storage system in real time. If the SOC data exceeds a preset range, the system starts the diesel generator set to charge the energy storage system or adjusts its operating mode.

5. The method according to claim 1, characterized in that, Implement a coordinated control strategy corresponding to the peak clipping mode, including: The diesel generator set is controlled to operate at a preset economic operating point power, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, and the preset ratio is greater than 0 and less than or equal to 1; The energy storage system is controlled to respond in real time to the power difference between the load power of the power distribution network system and the output power of the diesel generator set, and to discharge to make up for the power difference; The photovoltaic system is controlled to operate in a target photovoltaic power generation mode, and the output power of the photovoltaic system is preferentially supplied to the load. The target photovoltaic power generation mode includes: the photovoltaic inverter or controller adjusts the operating point in real time so that the photovoltaic array always operates at the maximum power output point under the current environmental conditions such as light and temperature.

6. The method according to claim 1, characterized in that, Implementing a coordinated control strategy corresponding to the fuel-saving mode, including: The diesel generator set is controlled to output power at a preset economic operating point, wherein the economic operating point power is the product of the rated power of the diesel generator set and a preset ratio, and the preset ratio is greater than 0 and less than or equal to 1. Compare the load power of the power distribution network system with the power at the economic operating point; If the load power of the power distribution network system is less than the economic operating point power, then the energy storage system is controlled to absorb the excess power of the diesel generator set for charging. If the load power of the power distribution network system is greater than the power at the economic operating point, the energy storage system is controlled to discharge to make up for the power difference.

7. The method according to claim 6, characterized in that, The method further includes: Monitor the state of charge data of the energy storage system; When the state of charge data of the energy storage system is detected to be less than the lower limit threshold of the target power range, the diesel generator set is forcibly started to charge the energy storage system. When the state of charge data of the energy storage system is detected to be greater than the upper limit threshold of the target power range, the energy storage system is used to supply power first, and the output power of the diesel generator set is reduced.

8. The method according to claim 1, characterized in that, Execute the control strategy corresponding to the fast power balancing mode, including: Detect whether the load power of the power distribution network system at the current moment is greater than the photovoltaic output power; If the load power is detected to be greater than the photovoltaic output power, the diesel generator set is controlled to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the power distribution network system in a stable state, and the energy storage system is controlled to adopt a target power control mode to compensate for the power difference between the load power and the target total output power. The target total output power is equal to the sum of the photovoltaic output power and the output power of the diesel generator set. The target power control mode includes: the power electronic converter in the energy storage system uses the received set value as an instruction to perform closed-loop control on the output active power and reactive power. If the detected load power is less than or equal to the photovoltaic output power, the diesel generator set is controlled to run under no-load, and the photovoltaic system is controlled to output limited power through the target photovoltaic power generation mode. At the same time, the energy storage system is controlled to adopt a constant voltage and constant frequency control mode to maintain the voltage and frequency of the distribution network system in a stable state, while absorbing the excess output power of the photovoltaic system.

9. The method according to claim 8, characterized in that, The energy storage system also uses an outer power prediction loop based on Kalman filtering to trigger control actions in advance when a sudden change in the photovoltaic output power is detected; and an inner power tracking loop based on model predictive control to achieve power tracking and detection.

10. A multi-mode operation device for a combined diesel and energy storage power supply system, characterized in that, include: The acquisition unit is used to collect the status parameters of the distribution network system in real time, wherein the status parameters include at least grid voltage, load power, photovoltaic output power and state of charge data of the energy storage system; The judgment unit is used to determine, based on the state parameters, whether the current state of the power distribution network system meets any preset operating mode switching condition. The first processing unit is used to select an operating mode from the backup power supply mode, load balancing mode, peak shaving mode, fuel saving mode and fast power balancing mode based on the current state and load demand of the distribution network system if the operating mode switching conditions are met. The execution unit is used to execute the coordinated control strategy corresponding to the selected operating mode, and to control the power output of the diesel generator set, energy storage system and photovoltaic system.

11. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program, wherein when the computer program is executed, the device containing the computer-readable storage medium performs the multi-mode operation method of the diesel-storage combined power supply system according to any one of claims 1 to 9.

12. An electronic device, characterized in that, It includes one or more processors and a memory, the memory being used to store one or more programs, wherein when the one or more programs are executed by the one or more processors, the one or more processors cause the one or more processors to perform the multi-mode operation method of the diesel-storage combined power supply system according to any one of claims 1 to 9.

13. A computer program product, characterized in that, It includes a computer program or instructions that, when executed by a processor, implement the multi-mode operation method of the diesel-storage combined power supply system as described in any one of claims 1 to 9.

Images