Capacity configuration method for wind power generation composite energy storage system

Abstract

The present invention discloses a capacity configuration method for a wind power generation composite energy storage system. The method analyzes the rated output power and rated output energy of the wind power generation composite energy storage system, based on the wind power generation composite energy storage system composed of a wind power generation system, a lithium battery energy storage unit, and a supercapacitor energy storage unit. A power configuration method is analyzed based on a power mathematical model in response to the composite energy storage power demand of the wind power generation system. A power configuration method is analyzed based on a power mathematical model in response to the composite energy storage power demand of the wind power generation system. A cost-based capacity configuration method is analyzed based on a cost mathematical model in response to the composite energy storage cost demand of the wind power generation system. The three configuration methods are comprehensively optimized to achieve reasonable capacity configuration of the wind power generation composite energy storage system.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy power generation planning, and in particular relates to a capacity configuration method for a wind power generation composite energy storage system. Background Art

[0002] Wind power systems capture wind energy through rotors, convert it into mechanical energy, and then convert it into electrical energy through generators. The advantages of wind power include: 1) clean, renewable energy, with no pollutants and minimal environmental impact; 2) low operating costs, as wind is a free energy source, and relatively low maintenance costs; 3) deployment at a wide range of scales, from small household systems to large wind farms; and 4) facilitating geographic energy diversification and reducing reliance on fossil fuels. However, wind power systems exhibit intermittent generation, which poses challenges to grid management, as grids must maintain a balance between supply and demand at any given moment.

[0003] To address the intermittent nature of wind power generation, energy storage systems can store excess electricity and release the stored electricity when the wind is insufficient to provide a continuous and stable power supply.

[0004] A common approach to hybrid energy storage configurations is to combine wind turbines with battery energy storage systems. Battery energy storage systems can store large amounts of energy and offer rapid response, releasing power quickly when wind speeds fluctuate. Other energy storage technologies, such as supercapacitors and hydrogen storage, can also be combined with wind turbines to achieve an even better hybrid energy storage ratio.

[0005] However, the current deployment of wind power and energy storage systems still faces several challenges. For example, the cost, lifespan, and efficiency of energy storage equipment still require further improvement. Furthermore, the design and management of wind power and energy storage systems require greater precision and intelligence to achieve optimal energy conversion and utilization efficiency. Summary of the Invention

[0006] In view of the above shortcomings of the prior art, the present invention provides a capacity configuration method for a wind power generation composite energy storage system.

[0007] The technical solution adopted by the present invention to solve its technical problems is: a capacity configuration method for a wind power generation composite energy storage system, based on a wind power generation composite energy storage system composed of a wind power generation system, a lithium battery energy storage unit, and a supercapacitor energy storage unit, the wind power generation system includes a rectifier unit and an inverter unit, the lithium battery energy storage unit includes a lithium battery and a converter, the supercapacitor energy storage unit includes a supercapacitor and a converter, the lithium battery energy storage unit and the supercapacitor energy storage unit are respectively connected to the wind power generation system through a DC / DC converter, the DC bus of the wind power generation system is connected to the power grid, and the power generation power and energy fluctuations of the wind power generation system are adjusted by a global capacity optimization configuration method based on power-capacity-cost, including the following steps

[0008] Step 1: Calculate the surplus power and energy of the wind power generation system:

[0009] Step 1.1, obtain the power generation power P of the wind power generation system N (t);

[0010] Step 1.2, calculate the power generation power P of the wind power generation system N (t) duration t;

[0011] Step 1.3, calculate the grid-connected power P of the wind power generation system OUT (t);

[0012] Step 1.4, calculate the grid-connected power P of the wind power generation system OUT (t) duration t;

[0013] Step 1.5, calculate the grid-connected power surplus of the wind power generation system, the surplus power P H (t):

[0014] P H (t) = P Li (t)+P SC (t) = P N (t)-P OUT (t);

[0015] Step 1.6, the surplus power P H (t) is decomposed into the steady-state fluctuating power P that needs to be regulated by the lithium battery energy storage unit Li (t) and the peak fluctuation power P that needs to be adjusted by the supercapacitor energy storage unit SC (t);

[0016] Rated output power P of wind power composite energy storage system HESS Satisfy the following formula:

[0017]

[0018] Where η1 represents the conversion efficiency of the DC / DC converter, η Li Indicates the charging efficiency of lithium battery, η SC represents the charging efficiency of the supercapacitor, h represents the operating cycle length, P N_min (t) represents the minimum value of the wind power generation system at a certain moment, P out_max (t) represents the maximum load demand at a certain moment,

[0019] Rated output energy E of wind power generation composite energy storage system HESS Satisfy the following formula:

[0020]

[0021] Step 2: Complete the following judgment by choosing one of the following methods:

[0022] Step 2.1: Determine whether the wind power generation composite energy storage system meets the power-capacity configuration function. The specific calculation formula is: P HESS (t) = P Li (t)+P SC (t)≥P H (t), calculate the power that meets the system requirements and the capacity that meets the system requirements;

[0023] Step 2.2: Determine whether the wind power generation composite energy storage system meets the energy-capacity configuration function. The specific calculation formula is: E HESS =E Li +E SC ≥E H , calculate the energy required to meet the system requirements, and the capacity required to meet the system requirements;

[0024] Step 2.3, determine whether the wind power generation combined energy storage system meets the cost-capacity configuration function. The specific calculation formula is: B SC +B Li ≤B, calculate the cost to meet the system requirements and the capacity to meet the system requirements;

[0025] Step 3: If it is determined that the wind power generation combined energy storage system satisfies at least two or more configuration functions, the configuration function with the lowest cost is selected to achieve a global optimal configuration of power-capacity-cost.

[0026] Furthermore, the power-capacity configuration is determined based on the power mathematical model in step 2.1 as follows:

[0027] Step 2.1.1, decompose and calculate the surplus power P H (t);

[0028] Step 2.1.2, assuming the lithium battery output is E Li, the supercapacitor output power is E SC When the wind power generation system is connected to the grid, the DC bus voltage is U (V), the battery charge and discharge rate is n (C), the battery cell capacity is K (Ah), the supercapacitor capacity is F, and the maximum output power of the lithium battery at a certain moment is P Li (t)=n*K*U, the maximum output power of the supercapacitor at a certain moment is

[0029] In step 2.1.3, the output power of the wind power generation and energy storage system can be obtained: P HESS (t) = P Li (t)+P SC (t);

[0030] Step 2.1.4: The output power of the energy storage system should be greater than or equal to the surplus power, that is,

[0031] P HESS (t) = P Li (t)+P SC (t)≥P H (t),

[0032] The energy storage ratio that meets the power configuration can be obtained.

[0033] Furthermore, the energy-capacity configuration is determined based on the energy mathematical model in step 2.2 as follows: Decomposition and calculation of surplus energy E H : The output energy of the energy storage system should be greater than or equal to the surplus energy, that is, E HESS =E Li +E SC ≥E H , the energy storage energy ratio that meets the energy configuration can be obtained.

[0034] Furthermore, the cost-capacity configuration is determined based on the cost mathematical model in step 2.3 as follows:

[0035] According to the surplus power and energy requirements of the wind power generation system, the cost of the energy storage system is determined to be B, and the unit price of the lithium battery is Q. Li , then the cost of lithium battery is B Li =Q Li *E Li ;

[0036] The unit price of supercapacitor is Q SC , then the cost of supercapacitor is B SC =Q SC *E SC ;

[0037] The cost of the energy storage system should be greater than or equal to the sum of the cost of lithium batteries and supercapacitors.SC +B Li ≤B, the energy storage ratio that meets the cost configuration can be obtained.

[0038] Furthermore, the analysis of energy storage configuration based on the power-capacity-cost mathematical model in step 3 is specifically as follows:

[0039] Step 3.1: Determine the energy storage capacity configuration based on the power, energy, and cost requirements of the energy storage system:

[0040]

[0041] Step 3.2: Based on the actual wind power generation system requirements, DC bus voltage U, battery charge and discharge rate n, supercapacitor charge and discharge rate m, and lithium battery unit price Q Li , supercapacitor cost unit price Q SC It has been determined that when there are multiple lithium battery and supercapacitor configurations, the lithium battery and supercapacitor energy configuration combination with the lowest cost is selected;

[0042] In step 3.3, a configuration method for the energy storage system that satisfies power, energy, and cost can be obtained.

[0043] The beneficial effects of the present invention are as follows: on the basis of a traditional wind power grid-connected system containing composite energy storage, the present invention discloses a global capacity optimization configuration strategy based on power-capacity-cost, which can reduce wind power generation fluctuations and load power shortage rate, and realize reasonable capacity configuration of the wind power composite energy storage system while considering actual costs, thereby ensuring power supply reliability and economic operation of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a schematic diagram of the wind power generation composite energy storage system of the present invention;

[0045] Figure 2 This is a flow chart of the capacity configuration method of the present invention. DETAILED DESCRIPTION

[0046] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0047] The present invention discloses a capacity configuration method for a wind power generation composite energy storage system, including power-capacity configuration, energy-capacity configuration, cost-capacity configuration and comprehensive optimization configuration. This embodiment of the wind power generation grid-connected system with composite energy storage includes a lithium battery energy storage unit, a supercapacitor energy storage unit, and a wind power generation system. The overall schematic diagram is as follows: Figure 1As shown, the wind power generation system includes a rectifier unit and an inverter unit, the lithium battery energy storage unit includes a lithium battery and a converter, and the supercapacitor energy storage unit includes a supercapacitor and a converter. The converters of the lithium battery energy storage unit and the supercapacitor energy storage unit are respectively connected to the rectifier unit and the inverter unit of the wind power generation system through DC / DC converters, and then connected to the power grid through a DC bus.

[0048] Reference Figure 2 As shown, the present invention provides a capacity configuration method for a wind power generation composite energy storage system, which adjusts the power generation power and energy fluctuations of the wind power generation system through a global capacity optimization configuration method based on power-capacity-cost, including the following steps.

[0049] Step 1: Calculate the surplus power and energy of the wind power generation system; the details are as follows.

[0050] Step 1.1, obtain the power generation power P of the wind power generation system N (t).

[0051] Step 1.2, calculate the power generation power P of the wind power generation system N (t) has a duration t.

[0052] Step 1.3, calculate the grid-connected power P of the wind power generation system OUT (t).

[0053] Step 1.4, calculate the grid-connected power P of the wind power generation system OUT (t) has a duration t.

[0054] Step 1.5, calculate the grid-connected power surplus of the wind power generation system, the surplus power P H (t): Surplus power P H (t) is the power that the wind power generation composite energy storage system needs to absorb or emit, and the formula is as follows:

[0055] P H (t) = P Li (t)+P SC (t) = P N (t)-P OUT (t).

[0056] Step 1.6, the surplus power P H (t) is decomposed into the steady-state fluctuating power P that needs to be regulated by the lithium battery energy storage unit Li (t) and the peak fluctuation power P that needs to be adjusted by the supercapacitor energy storage unit SC (t).

[0057] Rated output power P of wind power composite energy storage system HESS Satisfy the following formula:

[0058]

[0059] Where η1 represents the conversion efficiency of the DC / DC converter, η Li Indicates the charging efficiency of lithium battery, η SC represents the charging efficiency of the supercapacitor, h represents the operating cycle length, P N_min (t) represents the minimum value of the wind power generation system at a certain moment, P out_max (t) represents the maximum load demand at a certain moment, and the rated output energy E of the wind power generation composite energy storage system HESS Satisfy the following formula:

[0060]

[0061] Step 2, the composite energy storage capacity ratio flow chart is as follows Figure 2 As shown, the capacity of the wind power generation composite energy storage system is configured through the power-capacity configuration method, the energy-capacity configuration method, the cost-capacity configuration method and the comprehensive optimization configuration. Specifically, the following judgment is completed by selecting one of the methods.

[0062] Step 2.1: Determine whether the wind power generation composite energy storage system meets the power-capacity configuration function. The specific calculation formula is: P HESS (t) = P Li (t)+P SC (t)≥P H (t), calculate the power that meets the system requirements and the system capacity requirements. The power-capacity configuration based on the power mathematical model is as follows:

[0063] Step 2.1.1, decompose and calculate the surplus power P H (t).

[0064] Step 2.1.2, assuming the lithium battery output is E Li , the supercapacitor output power is E SC When the wind power generation system is connected to the grid, the DC bus voltage is U (V), the battery charge and discharge rate is n (C), the battery cell capacity is K (Ah), the supercapacitor capacity is F, and the maximum output power of the lithium battery at a certain moment is P Li (t)=n*K*U, the maximum output power of the supercapacitor at a certain moment is

[0065] In step 2.1.3, the output power of the wind power generation and energy storage system can be obtained: P HESS (t) = P Li (t)+P SC (t).

[0066] Step 2.1.4: Ensure that the output power of the energy storage system is greater than or equal to the surplus power, that is,

[0067] P HESS (t) = P Li (t)+P SC (t)≥P H (t)

[0068] The energy storage ratio that meets the power configuration can be obtained.

[0069] Step 2.2: Determine whether the wind power generation composite energy storage system meets the energy-capacity configuration function. The specific calculation formula is: E HESS =E Li +E SC ≥E H , calculate the energy that meets the system requirements and at the same time meet the system capacity requirements. Based on the energy mathematical model, the energy-capacity configuration is analyzed as follows:

[0070] Decomposition calculation of surplus energy E H : The output energy of the energy storage system should be greater than or equal to the surplus energy, that is: E HESS =E Li +E SC ≥E H , the energy storage energy ratio that meets the energy configuration can be obtained.

[0071] Step 2.3, determine whether the wind power generation combined energy storage system meets the cost-capacity configuration function. The specific calculation formula is: B SC +B Li ≤B, calculate the cost that meets the system requirements and meets the system capacity requirements. Cost-capacity configuration method based on cost mathematical model analysis:

[0072] Step 2.3.1: Determine the energy storage system cost B based on the surplus power and energy requirements of the wind power generation system.

[0073] Step 2.3.2, lithium battery unit price Q Li , then the cost of lithium battery is: B Li =Q Li *E Li .

[0074] Step 2.3.3, supercapacitor cost unit price Q SC , then the cost of supercapacitor is: B SC =Q SC *E SC .

[0075] Step 2.3.4: The energy storage system cost should be greater than or equal to the sum of the lithium battery cost and the supercapacitor cost:

[0076] B SC +B Li ≤B

[0077] The energy storage ratio that meets the cost configuration can be obtained.

[0078] Step 3: If it is determined that the wind power generation and energy storage system meets at least two or more configuration functions, the configuration function with the lowest cost is selected to achieve the global optimal configuration of power-capacity-cost. The specific method for analyzing energy storage configuration based on the power-capacity-cost mathematical model is as follows:

[0079] Step 3.1: Determine the energy storage capacity configuration based on the power, energy, and cost requirements of the energy storage system:

[0080]

[0081] Step 3.2: Based on the actual wind power generation system requirements, DC bus voltage U, battery charge and discharge rate n, supercapacitor charge and discharge rate m, and lithium battery unit price Q Li , supercapacitor cost unit price Q SC Confirmed.

[0082] Step 3.3: When there are multiple lithium battery and supercapacitor energy configurations obtained according to steps 3.1 and 3.2, the lithium battery and supercapacitor energy configuration combination with the lowest cost is selected.

[0083] Step 3.4: Based on steps 3.1, 3.2, and 3.3, a configuration method for an energy storage system that satisfies power, energy, and cost requirements can be obtained.

[0084] It is easy for those skilled in the art to understand that the above description is only a preferred use case of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A capacity configuration method for a wind power generation composite energy storage system, based on a wind power generation composite energy storage system consisting of a wind power generation system, a lithium battery energy storage unit, and a supercapacitor energy storage unit. The wind power generation system includes a rectifier unit and an inverter unit, the lithium battery energy storage unit includes a lithium battery and a converter, and the supercapacitor energy storage unit includes a supercapacitor and a converter. The lithium battery energy storage unit and the supercapacitor energy storage unit are respectively connected to the wind power generation system via a DC / DC converter, and the DC bus of the wind power generation system is connected to the power grid. The method is characterized in that: Includes the following steps Step 1: Calculate the surplus power and energy of the wind power generation system: Step 1.1: Obtain the power generated by the wind power generation system ; Step 1.2, calculate the power generation of the wind power system Duration t ; Step 1.3, calculate the grid-connected power of the wind power generation system ; Step 1.4, calculate the grid-connected power of the wind power generation system Duration t ; Step 1.5, calculate the grid-connected power surplus of the wind power generation system, the surplus power ; Step 1.6: Convert surplus power Decomposed into steady-state fluctuating power that needs to be regulated by lithium battery energy storage units and peak power fluctuations that need to be regulated by supercapacitor energy storage units ; Rated output power of wind power composite energy storage system Satisfy the following formula: ， in Indicates the conversion efficiency of the DC / DC converter, Indicates the charging efficiency of lithium batteries, Indicates the charging efficiency of the supercapacitor, h Indicates the duration of the operation cycle. Indicates the minimum value of the wind power generation system at a certain moment, Indicates the maximum load demand at a certain moment; Rated output energy of wind power composite energy storage system Satisfy the following formula: ； Step 2: Complete the following judgment by choosing one of the following methods: Step 2.1: Determine whether the wind power generation and energy storage system meets the power-capacity configuration function: , calculate the power and capacity that meet the system requirements; Step 2.2: Determine whether the wind power generation and energy storage system meets the energy-capacity configuration function: , calculate the energy and capacity to meet the system requirements; Step 2.3: Determine whether the wind power generation combined energy storage system meets the cost-capacity configuration function: , calculate the cost and capacity to meet the system requirements; Step 3: If the wind power generation and energy storage system meets at least two configuration functions, the configuration function with the lowest cost is selected to achieve the global optimal configuration of power, capacity and cost: Step 3.1: Determine the energy storage capacity configuration based on the power, energy, and cost requirements of the energy storage system: ， in is the surplus power, Output power for lithium battery, Output power to the supercapacitor. Output power of wind power generation composite energy storage system, is surplus energy; Step 3.2: Based on the actual requirements of the wind power generation system, the DC bus voltage U, the battery charge and discharge rate n, the supercapacitor charge and discharge rate m, and the lithium battery unit price , supercapacitor cost unit price , when there are multiple sets of lithium battery and supercapacitor configurations, take the lithium battery and supercapacitor energy configuration combination with the lowest cost; Step 3.3: Find the energy storage system configuration method that satisfies power, energy and cost simultaneously.

2. The capacity configuration method of a wind power generation composite energy storage system according to claim 1, characterized in that: The power-capacity configuration is determined in step 2.1 as follows: Step 2.1.1, Decomposition and Calculation of Surplus Power ; Step 2.1.2, assume the output power of the lithium battery is , the supercapacitor output power is When the wind power generation system is connected to the grid, the DC bus voltage is U, the battery charge and discharge rate is n, the cell capacity is K, and the supercapacitor capacity is F. The maximum output power of the lithium battery at a certain moment is , the maximum output power of the supercapacitor at a certain moment is ; Step 2.1.3, calculate the output power of the wind power generation and energy storage system: ； Step 2.1.4: Ensure that the output power of the energy storage system is greater than or equal to the surplus power, and obtain the energy storage energy ratio that meets the power configuration.

3. The capacity configuration method of a wind power generation composite energy storage system according to claim 2, characterized in that: The energy-capacity configuration determined in step 2.2 is specifically as follows: Decomposition and calculation of surplus energy , ensure that the output energy of the energy storage system is greater than or equal to the surplus energy, and obtain the energy storage energy ratio that meets the energy configuration.

4. The capacity configuration method of a wind power generation composite energy storage system according to claim 3, characterized in that: The cost-capacity configuration in step 2.3 is specifically determined as follows: Based on the surplus power and energy requirements of the wind power generation system, the energy storage system cost is determined to be B, and the lithium battery cost unit price is , then the cost of lithium battery is ; The unit cost of supercapacitor is , then the cost of supercapacitor is ; Ensure that the cost of the energy storage system is greater than or equal to the sum of the cost of lithium batteries and supercapacitors, and obtain the energy storage energy ratio that meets the cost configuration.

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