Self-adaptive charging and discharging method and system for energy storage device of ship electric power system

Abstract

The invention provides a self-adaptive charging and discharging method and system for an energy storage device of a ship electric power system, and the method comprises the steps: constructing a charging and discharging power function of the energy storage device, and introducing parameters, such as the power of power supply equipment, a load rate limiting value and a current load, which can be in a network into the function, so as to reflect the operation boundary and the current state of the system; the obtained charging and discharging power instruction of the energy storage device is adaptively adjusted according to the operation boundary and the current state of the system, the current and subsequent electrical load changes of various working conditions are automatically adapted, and the power instruction of the energy storage device can be always in a reasonable range without manually and frequently adjusting the power instruction of the energy storage device; and the function of improving the available power of the system in a long time period is realized.

Description

Technical Field

[0001] This invention belongs to the field of energy storage system configuration and operation control technology, specifically relating to an adaptive charging and discharging method and system for a ship power system energy storage device. Background Technology

[0002] With the increasing use of high-power pulse loads and the integration of various new energy sources, shipboard power systems are gradually incorporating large-capacity energy storage devices to meet the power demands of special loads or ensure the stable operation of the power system. These energy storage devices have large capacities and charging / discharging power, typically only an order of magnitude lower than the shipboard power system's power rating. Furthermore, their bidirectional power controllability allows them to participate in power system operation alongside other power supply equipment. Therefore, utilizing these energy storage devices to temporarily boost the system's available power under special mission conditions or emergency situations involving power supply equipment capacity loss provides a possibility for optimizing the capacity configuration of shipboard power system equipment.

[0003] Conventional power control methods for energy storage devices primarily rely on the device's own capacity and status, instructing it to charge and discharge according to a given power command, or determining the charging and discharging command based on the device's current energy storage capacity. Due to limited consideration of factors across the entire power system, these methods have limitations in supporting optimized system operation. Therefore, designing charging and discharging strategies for energy storage devices that consider the overall system capacity, including the device itself, to adaptively adjust charging and discharging power based on the system's status, including the device, other power supply equipment, and loads, and to enhance the system's available power and provide power and energy support over a longer period, is a problem worthy of further research. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an adaptive charging and discharging method and system for a ship power system energy storage device, which can improve the available power of the system over a long period of time.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is as follows: an adaptive charging and discharging method for a ship's power system energy storage device, comprising the following steps: Construct the charge and discharge power function of the energy storage device; The energy storage device's charging and discharging power commands are adaptively adjusted based on the system's operating boundaries and current state to automatically adapt to changes in electricity load.

[0006] According to the above scheme, let the upper limit of the average load factor of the power supply equipment be α. max The total rated power of the power supply equipment that can operate on the grid is P. SE The rated charging and discharging power between the energy storage device and the power grid is P. ESSE When the energy storage device is discharging normally, the upper limit of the system's available power P maxfor: P max = α max ·P SE + P ESSE .

[0007] Furthermore, let α be the limit value of the average load factor of the power supply equipment on the grid when the energy storage device begins to discharge. d <α max .

[0008] Furthermore, when the system is operating under conditions that increase the discharge of power supply equipment and decrease the discharge of energy storage devices, α d Approaching α max .

[0009] According to the above scheme, let the power generation capacity of the power supply equipment be P. S The energy storage device's charging and discharging power is P. ESS Then the load power P L =P S + P ESS Load power P L P should be satisfied L ≤P max If P L >P max Then the load power P is limited. L To satisfy P L ≤P max .

[0010] Furthermore, the energy storage state S of the energy storage device is the ratio of the current stored energy to the rated stored energy; the permissible operating range of the energy storage state S of the energy storage device is [S l , S h If the energy storage state S of the energy storage device decreases to the lower limit S... l Then the load power P is limited. L To satisfy P L ≤α max ·P SE .

[0011] Furthermore, when the average load factor of the system's on-grid power supply equipment does not exceed α d When the energy storage device does not discharge, the energy storage device does not discharge if the energy storage state S of the energy storage device has not reached the upper limit S. h Then, when charging the energy storage device, the charging power shall not exceed the rated charging and discharging power P between the energy storage device and the grid. ESSE Charging power plus load power P L Afterwards, the average load factor of the system's on-grid power supply equipment still does not exceed α. d The charging and discharging power function of the energy storage device is: P ESS = - min[αd ·P SE - P L , P ESSE ]; If the energy storage state S of the energy storage device reaches its upper limit S h If the energy storage device does not charge, P ESS = 0.

[0012] Furthermore, when the average load factor of the system's on-grid power supply equipment exceeds α d At that time, the energy storage device discharges to the grid, and the discharge power increases with the increase of load power; to ensure a smooth transition in the power generation of the power supply equipment when the load power changes, let P... L = α d ·P SE P ESS = 0, and P L = P max P ESS = P ESSE Energy storage device charge / discharge power function P ESS = ƒ(P L The expression can be represented as a linear function: P ESS = (P L - α d ·P SE ) / (P max - α d ·P SE )·P ESSE .

[0013] An adaptive charging and discharging system for energy storage devices in a ship's electrical system. The function construction submodule is used to construct the charging and discharging power functions of the energy storage device; The instruction adjustment submodule is used to adaptively adjust the charging and discharging power instructions of the energy storage device according to the system's operating boundaries and current state, so as to automatically adapt to changes in electricity load.

[0014] A computer memory storing a computer program executable by a computer processor, the computer program executing an adaptive charging and discharging method for a ship's power system energy storage device.

[0015] The beneficial effects of this invention are as follows: 1. The present invention provides an adaptive charging and discharging method and system for a ship power system energy storage device. By constructing a charging and discharging power function for the energy storage device, parameters such as the power of grid-connected power supply equipment, load rate limits, and current load are introduced into the function to reflect the operating boundary and current state of the system. The resulting charging and discharging power command for the energy storage device is adaptively adjusted according to the operating boundary and current state of the system, automatically adapting to changes in power load under various current and subsequent operating conditions. It can keep the power command of the energy storage device within a reasonable range without the need for frequent manual adjustments. This achieves the function of increasing the available power of the system over a long period of time.

[0016] 2. This invention targets high-power energy storage devices that can participate in the operation of ship power systems. On the one hand, it fully utilizes the discharge capacity of the energy storage device to increase the upper limit of the available power of the power system under special operating conditions. On the other hand, it extends the time period during which the energy storage device provides power and energy support to the system or reduces the demand for the capacity of the energy storage device, supporting the optimized configuration and operation of the entire system. Discharge only begins after the system load exceeds the set range, which can fully utilize the power supply capacity of other power supply equipment and extend the time during which the energy storage device can provide power and energy support.

[0017] 3. This invention can be automatically extended to different operating conditions and even different target images. While improving the power and energy support capability of the energy storage device for the system, it has good universality and flexibility. It is generally applicable to various systems with different rated power of power supply equipment, rated charging and discharging power of energy storage device, and capacity of energy storage device.

[0018] 4. This invention can flexibly set parameters such as the upper limit of the average load rate of power supply equipment, the limit of the average load rate of power supply equipment on the grid when the energy storage device starts discharging, and the upper and lower limits of the energy storage status of the energy storage device according to requirements, so as to adapt to various operating conditions and target images; it can automatically and smoothly switch the discharge and charging strategies of the energy storage device according to the current system load rate and the energy storage status of the energy storage device, without having to consider the timing and strategy of charging the energy storage device, making the control mode simpler; it can also automatically charge at the maximum charging power allowed by the system and the energy storage device itself when there is no need to discharge, so as to replenish energy as quickly as possible and have the ability to improve the available power of the system and provide power and energy support for the system over a longer period of time.

[0019] Of course, any product implementing this invention does not necessarily need to achieve all of the advantages described above at the same time. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is a flowchart of an embodiment of the present invention.

[0022] Figure 2 This is a simulation result diagram of Embodiment 1 of the present invention.

[0023] Figure 3 This is a simulation result diagram of Embodiment 2 of the present invention. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the 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 merely illustrative and not intended to limit the invention.

[0025] Example 1 See Figure 1 The specific steps of an adaptive charging and discharging method for a ship's power system energy storage device are as follows: Let the upper limit of the average load factor of the power supply equipment be α. max The average load factor limit for grid-connected power supply equipment when the energy storage device begins to discharge is α. d ; there is α d <α max α can be set according to needs and system characteristics. d and α max If the goal is to maximize the discharge of the system's power supply equipment and minimize the discharge required by the energy storage device, then α can be set. d Approaching α max .

[0026] Let P be the total rated power of the power supply equipment that can operate on the grid. SE The rated charging and discharging power between the energy storage device and the power grid is P. ESSE The power generation capacity of the power supply equipment is P. S The energy storage device discharge power is P ESS The load power is P L Then P S + P ESS =P L Let the ratio of the current stored energy to the rated stored energy Q of the energy storage device be the energy storage state S, and the allowable operating range of the energy storage state be S∈[S...]. l , S h].

[0027] As can be seen from the above settings, when the energy storage device can discharge normally, the upper limit of the system's usable power P is... max = α max ·P SE +P ESSE Therefore, P should exist. L ≤P max ; such as P L >P max If the load exceeds the system's power supply capacity, it is necessary to limit the load power P. L Measures to satisfy P L ≤P max If the energy storage state S of the energy storage device decreases to the lower limit S... l Similarly, it is necessary to limit the load power P. L Measures to satisfy P L ≤α max ·P SE .

[0028] When the average load factor of the system's on-grid power supply equipment does not exceed α d At this time, the energy storage device does not participate in discharging. If the energy storage state S of the energy storage device has not reached its upper limit S... h Then charge it, the charging power shall not exceed P ESSE Furthermore, even after the charging power is added to the load power, the average load factor of the grid-connected power supply equipment in the system still does not exceed α. d That is, P ESS = - min[α d ·P SE - P L ,P ESSE If the energy storage state S of the energy storage device reaches its upper limit S; h If the energy storage device does not charge, then P will be available. ESS = 0.

[0029] When the average load factor of the system's on-grid power supply equipment exceeds α d At that time, the energy storage device discharges to the grid, and the discharge power increases with the increase of load power; in order to ensure that the power generation power of the power supply equipment changes as smoothly as possible when the load power changes, let P L =α d ·P SE P ESS = 0, and P L = P max P ESS = P ESSE P that satisfies the above two conditions ESS = ƒ(P LThe functional relationship should be monotonic; a simple linear function or other suitable monotonic functions can be used. (Using P...) ESS = ƒ(P L Taking a linear function as an example, we have P ESS = (P L - α d ·P SE ) / (P max - α d ·P SE )·P ESSE This embodiment constructs a charging and discharging power function for the energy storage device, incorporating parameters such as the power of grid-connected power supply equipment, load rate limits, and current load to reflect the system's operating boundaries and current state. This allows the resulting charging and discharging power command for the energy storage device to adaptively adjust based on the system's operating boundaries and current state, automatically adapting to changes in power load under various current and subsequent operating conditions. It eliminates the need for frequent manual adjustments to the energy storage device's power command, ensuring it remains within a reasonable range. This achieves the function of increasing the system's available power over long periods.

[0030] Example 2 The steps in this embodiment are the same as in Embodiment 1, except that each step is applied to a specific instance. Specifically, it includes the following steps: Two implementation cases are given below for different operating conditions of the same ship target image, with corresponding parameters shown in Table 1. Implementation case 1 simulates the normal operating condition of power supply equipment that can operate on the grid, while implementation case 2 simulates the operating condition of power supply equipment that can operate on the grid with power loss. Function P ESS = ƒ(P L All use linear functions P ESS = (P L - α d ·P SE ) / (P max -α d ·P SE )·P ESSE The simulation results for Case 1 and Case 2, using the adaptive charge / discharge strategy of the energy storage device described in this invention, are as follows: Figure 1 , Figure 2 As shown.

[0031] Depend on Figure 2 It can be seen that when P SE = 10MW, P ESSEWhen the load power fluctuation curve reaches a maximum of 10.4MW, the adaptive charging and discharging strategy of the energy storage device described in this invention enables reasonable power allocation between the power supply equipment and the energy storage device. The average load factor of the power supply equipment never exceeds the upper limit of 0.95, and the load factor P of the energy storage device... ESS / P ESSE Less than the average load factor P of the power supply equipment S / P SE This indicates that the discharge power of the energy storage device was effectively reduced; at the same time, the energy storage device was charged with the maximum available charging power immediately after exiting the discharge state, replenishing the energy as quickly as possible; all of the above measures extended the time that the energy storage device could provide power and energy support.

[0032] Depend on Figure 3 It can be seen that when P SE = 2MW, P ESSE When the load power fluctuation curve has a maximum value of 2.5MW, the adaptive charging and discharging strategy of the energy storage device described in this invention is still applicable. This shows that the charging and discharging strategy has universal adaptability to different operating conditions of the same target image. It also shows that the charging and discharging strategy is applicable to target images with different power supply equipment power / energy storage device power ratios and different power levels.

[0033] Table 1 Implementation Case Parameters

[0034] This embodiment allows for flexible setting of parameters such as the upper limit of the average load rate of power supply equipment, the limit of the average load rate of on-grid power supply equipment when the energy storage device starts discharging, and the upper and lower limits of the energy storage status of the energy storage device, to adapt to various operating conditions and target images. It can automatically and smoothly switch the discharge and charging strategies of the energy storage device according to the current system load rate and the energy storage status of the energy storage device, without the need to consider the timing and strategy of charging the energy storage device, making the control mode simpler. It can also automatically charge at the maximum charging power allowed by the system and the energy storage device itself when there is no need to discharge, so as to replenish energy as quickly as possible and have the ability to improve the available power of the system and provide power and energy support for the system over a longer period of time.

[0035] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0036] Example 3 This embodiment is used to implement the principle of the above method embodiment to construct an adaptive charging and discharging system for a ship power system energy storage device, including a function construction submodule and an instruction adjustment submodule; The function construction submodule is used to construct the charging and discharging power functions of the energy storage device; The instruction adjustment submodule is used to adaptively adjust the charging and discharging power instructions of the energy storage device according to the system's operating boundaries and current state, so as to automatically adapt to changes in electricity load.

[0037] Each submodule is mainly used to implement the various steps of the method implementation, which will not be elaborated here.

[0038] It should be noted that, depending on the implementation needs, the various steps / components described in this application can be broken down into more steps / components, or two or more steps / components or parts of the operation of steps / components can be combined into new steps / components to achieve the purpose of this invention.

[0039] This embodiment also includes a processor, a communication interface, a memory, and a communication bus; wherein the processor, the communication interface, and the memory communicate with each other through the communication bus; the memory stores a computer program, and when the program is executed by the processor, the processor performs the steps of an adaptive charging and discharging method for a ship power system energy storage device.

[0040] This embodiment also provides a computer-readable storage medium storing executable instructions that, when executed by a processor, enable the processor to implement an adaptive charging and discharging method for a ship power system energy storage device.

[0041] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects.

[0042] Furthermore, this application may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0043] This application is described with reference to the flowchart of the method and computer program product according to Embodiment 1 and the block diagram of the device (system) according to Embodiment 3. It should be understood that each step or block in the flowchart or block diagram, as well as combinations of steps or blocks in the flowchart or block diagram, can be implemented by computer program instructions.

[0044] These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing device to produce a machine, such that the instructions, which are executable by the processor of the computer or other programmable data processing device, produce instructions for implementing the process. Figure 1 One or more processes or boxes Figure 1An adaptive charge and discharge system for a ship's electrical system energy storage device, specifying the functions in one or more boxes.

[0045] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes or boxes Figure 1 The function specified in one or more boxes.

[0046] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes or boxes Figure 1 The steps of an adaptive charging and discharging method for a marine electrical system energy storage device are specified in one or more boxes.

[0047] The above embodiments are only used to illustrate the design concept and features of the present invention, and their purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. The protection scope of the present invention is not limited to the above embodiments. Therefore, all equivalent changes or modifications made based on the principles and design ideas disclosed in the present invention are within the protection scope of the present invention.

Claims

1. A method for adaptive charging and discharging of a ship power system energy storage device, characterized by: The method comprises the following steps: constructing a charge-discharge power function of the energy storage device; adjusting the charge-discharge power instruction of the energy storage device according to the operation boundary and current state of the system to automatically adapt to the change of the power load.

2. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 1, characterized in that: The upper limit of the average load rate of the power supply device is α max The total rated power of the power supply device running on the network is P SE The rated charge and discharge power between the energy storage device and the power grid is P ESSE When the energy storage device is normally discharged, the upper limit P max of the available power of the system is: P max = α max ·P SE + P ESSE .

3. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 2, characterized in that: Let the average load rate limit α of the power supply equipment of the grid when the energy storage device starts discharging d <α max .

4. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 3, characterized in that: When in the working condition of increasing the discharging of the system power supply device and reducing the discharging of the energy storage device, α d Approaching α max .

5. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 1, characterized in that: Suppose the power generation of the power supply device is P S , the charge and discharge power of the energy storage device is P ESS , then the load power P L =P S + P ESS ; Load power P L P L should be satisfied max ; if P L > P max , limit the load power P L so that P L ≤ P max .

6. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 2 or 5, characterized in that: The energy storage state S of the energy storage device is the ratio of the current stored energy to the rated stored energy; the range of the energy storage state S of the energy storage device allowed to operate is [S l , S h ]. If the state of charge S of the energy storage device decreases to the lower limit S l , then the load power P L is limited so as to satisfy P L ≤ α max · P SE .

7. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 3 or 5, characterized in that: When the average load rate of the system in the grid power supply device does not exceed α d , the energy storage device is not discharged; If the energy storage state S of the energy storage device does not reach the upper limit S h , the energy storage device is charged, and the charging power does not exceed the rated charge-discharge power P ESSE between the energy storage device and the power grid; after the charging power is superimposed on the load power P L , the average load rate of the grid power supply equipment still does not exceed α d ; the charge-discharge power function of the energy storage device is: P ESS = - min[α d ·P SE - P L , P ESSE ] If the state of charge S of the energy storage device reaches the upper limit S h , then the energy storage device is not charged, P ESS = 0.

8. The adaptive charge-discharge method of the energy storage device of the ship power system according to claim 7, characterized in that: When the average load rate of the system exceeds α d , the energy storage device discharges to the power grid, and the discharge power increases with the increase of the load power. To ensure the smooth transition of the power generation of the power supply equipment when the load power changes, let P L = α d ·P SE Time P ESS = 0, and P L = P max Time P ESS = P ESSE ; Energy storage device charge-discharge power function P ESS = ƒ(P L ) is expressed as a linear function P ESS = (P L - α d ·P SE ) / (P max - α d ·P SE )·P ESSE .

9. An adaptive charge-discharge system of an energy storage device of a ship power system, characterized in that: a function construction submodule for constructing a charge-discharge power function of the energy storage device; an instruction adjustment submodule for adjusting the charge-discharge power instruction of the energy storage device according to the operation boundary and current state of the system to automatically adapt to the change of the power load.

10. A computer memory, characterized by: The computer program stored in the memory can be executed by the computer processor, and the computer program executes the adaptive charge-discharge method of the energy storage device of the ship power system according to any one of claims 1 to 8.

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