Comprehensive energy system configuration method considering DC / DC connection of electric agricultural machine

Abstract

The invention relates to the technical field of new energy, and provides a comprehensive energy system configuration method considering DC / DC connection of an electric agricultural machine, which comprises the following steps: constructing an optimization model of an agricultural machine battery participating in a rural system, the constraint conditions of the optimization model comprise different agricultural machine battery capacity constraints, system power balance constraints, investment constraints, agricultural machine battery comprehensive station capacity constraints and agricultural machine battery comprehensive station number constraints; solving the optimization model to obtain the capacity of the agricultural machine battery comprehensive station; and according to the solved optimal capacity, constructing a battery comprehensive station to participate in the operation of the rural energy system. The comprehensive energy system configuration method can solve the problems that agricultural machinery batteries are not fully utilized, electric agricultural machinery batteries are scattered, management of the batteries is little, and the batteries are almost not used in the slack season, and meanwhile solves the problems that the agricultural machinery batteries only depend on rural power grids, impact on the rural power grids is large in the busy season, and the stability of the power grids is not facilitated.

Description

Technical Field

[0001] The present invention relates to the field of new energy technologies, and in particular to a method for configuring an integrated energy system taking into account DC / DC connections of electric agricultural machinery. Background Art

[0004] Existing electric agricultural machinery generally only works during the busy farming season and is idle during the slack season. This is a waste of resources and also affects the life of the battery. At the same time, the battery load of agricultural machinery has a greater impact on rural areas with weak power grids. There is a lack of agricultural machinery battery management. Current research on electric agricultural machinery mainly focuses on battery charging and discharging, as well as the mechanical and control design of agricultural machinery. There is less research on the management of agricultural machinery batteries and battery charging load.

[0005] Therefore, it is necessary to design an energy storage configuration method that considers the electric energy substitution of large-scale farm machinery and the DC / DC connection of the integrated energy system to solve the above technical problems. Summary of the invention

[0006] The object of the present invention is to at least partially overcome the deficiencies of the prior art and to provide a method for configuring an integrated energy system taking into account DC / DC connections of electric agricultural machinery.

[0007] The purpose of the present invention is also to provide an integrated energy system configuration method taking into account the DC / DC connection of electric agricultural machinery, so as to solve the problems mentioned in the above background technology that agricultural machinery batteries are not fully utilized, electric agricultural machinery batteries are scattered, there is little management of batteries, and batteries are almost not used during the slack season.

[0008] The present invention also aims to provide a comprehensive energy system configuration method that takes into account the DC / DC connection of electric agricultural machinery, so as to solve the problems that agricultural machinery batteries rely solely on rural power grids, have a great impact on rural power grids during busy farming seasons, and are not conducive to power grid stability.

[0009] To achieve the above purpose or one of the purposes, the technical solutions of the present invention are as follows:

[0010] A method for configuring an integrated energy system considering DC / DC connections of electric agricultural machinery, the method comprising:

[0011] Construct an optimization model for the participation of agricultural machinery batteries in rural systems. The optimization model takes economic efficiency and carbon emissions as optimization objectives. The constraints of the optimization model include: capacity constraints of different agricultural machinery batteries, system power balance constraints, investment constraints, capacity constraints of agricultural machinery battery integrated stations, and constraints on the number of agricultural machinery battery integrated stations.

[0012] Solving the optimization model to obtain the capacity of the agricultural machinery battery integrated station;

[0013] Based on the solved optimal capacity, a battery integrated station is built to participate in the operation of the rural energy system.

[0014] According to a preferred embodiment of the present invention, the objective function related to economy in the optimization model includes the construction cost, operation and maintenance cost, and energy purchase cost from outside of the comprehensive battery station for electric agricultural machinery; the objective function is as follows:

[0015] min f1=C inv +C opt -C out

[0016] In the formula, C inv is the annual investment cost of the comprehensive battery station, C opt is the operation and maintenance cost of the comprehensive battery station, and C out is the income of the comprehensive battery station;

[0017] The objective function related to carbon emissions in the optimization model includes the carbon emissions from purchasing electricity from the power grid and the carbon emissions reduced by using new energy; the objective function related to carbon emissions is as follows:

[0018] min f2=T buy -T neg

[0019] In the formula, T buy is the carbon emissions from purchasing electricity from the power grid, and T neg is the carbon emissions reduced by using new energy.

[0020] According to a preferred embodiment of the present invention, the expressions of the annual investment cost of the comprehensive battery station, the operation and maintenance cost of the comprehensive battery station, and the income of the comprehensive battery station are respectively:

[0021]

[0022]

[0023]

[0024] In the formula, c inv is the investment cost per unit capacity of the battery; X is the total configured capacity of the agricultural machinery battery; c mai is the annual operation and maintenance cost per unit capacity of the battery; y is the equipment life cycle; r is the discount rate; is the price of the system purchasing electricity from the power grid at time t; is the electricity purchase quantity of the system in time period t; is the price of the system selling electricity to the power grid at time t; is the grid-connected electricity quantity of the system in time period t.

[0025] According to a preferred embodiment of the present invention, the expression of carbon emissions is:

[0026]

[0027]

[0028] In the formula, is the carbon emission coefficient of electric energy in the external power grid during the t period; is the purchased power of the system during the t period, is the power input from the rural new energy generator set to the agricultural machinery battery integrated station at the t moment.

[0029] According to the preferred embodiment of the present invention, the expression of the system power balance constraint is as follows:

[0030] P i (t) + P buy (t) + P d (t) = P load (t) + P loss (t) + P c (t)

[0031] In the formula, P i (t) is the power generation power of the conventional equipment in the rural energy system during the t period; P buy (t) is the power purchased from the power grid by the system at the t moment, P c (t), P d (t) are the charging and discharging powers of the agricultural machinery battery integrated station at the t moment; P load (t) is the system electrical load at the t moment, P loss (t) is the active power loss of the system during the t period;

[0032] The expression of the investment constraint is as follows:

[0033] T max ≥ f in (n)

[0034] In the formula, T max is the maximum investment capacity of the agricultural machinery battery integrated station; f in (n) is the sum of the initial investments of the equipment in the agricultural machinery battery integrated station;

[0035] The expression of the constraint of the planned area is as follows:

[0036] xm ≤ S max

[0037] In the formula, m is the land area occupied by the installation of a single battery; S max is the available land area for building the integrated energy system;

[0038] The expression of the capacity constraint of the agricultural machinery battery integrated station is as follows:

[0039] Ees,min ≤ E es,m ≤ E es,max

[0040] Wherein, E es,max and E es,min are respectively the upper and lower limits of the electrical energy stored in the battery of the agricultural machinery battery integrated station;

[0041] The constraints related to the operation of the agricultural machinery battery also include:

[0042] 0 ≤ P c,t ≤ λ c,t P es,r (1)

[0043] 0 ≤ P d,t ≤ λ d,t P es,r (2)

[0044] λ c,t + λ d,t ≤ 1 (3)

[0045] P c,t · P d,t = 0 (4)

[0046] E es,t = E es,t-1 +(η c P c,t - P d,t / η d )· Δt (5)

[0047] The charging and discharging process of the agricultural machinery battery integrated station has the following constraints: the charging and discharging power shall not exceed the rated power value, as required by formulas (1)-(3); it can only be in one of the charging, discharging or static states at a certain time period, as required by formula (4); the electrical energy in the current time period, the charging and discharging efficiency, the charging and discharging power in the current time period, and the electrical energy in the previous time period are as required by formula (5);

[0048] Wherein, λ c,t and λ d,t respectively represent the 0-1 variables of the charging and discharging of the agricultural machinery battery at time t; E es,t and E es,t-1 are the electrical energies stored at time t and t-1; η c and η d respectively represent the charging and discharging efficiencies of the energy storage.

[0049] According to another aspect of the present invention, there is provided a battery management method for electric agricultural machinery. The agricultural machinery battery integrated station is divided into three parts: an agricultural machinery battery detection and processing module, an agricultural machinery battery storage module, and an idle agricultural machinery garage. The agricultural machinery battery detection and processing module calculates the load of agricultural machinery for the next day by analyzing data on the working type, working duration, and operating environment of agricultural machinery for the next day. The agricultural machinery battery storage module facilitates the unified management and scheduling of agricultural machinery batteries.

[0050] According to a preferred embodiment of the present invention, the agricultural machinery battery integrated station is close to the farm and the living area of farmers. The agricultural machinery batteries are connected by cables and are provided with fixed card slots for easy removal and placement of agricultural machinery batteries. At the same time, the agricultural machinery battery integrated station is connected to the rural energy system by cables, and a temperature control system is provided in the agricultural machinery battery storage module.

[0051] According to a preferred embodiment of the present invention, the agricultural machinery battery integrated station includes a processor and a detector for detecting the life cycle of each agricultural machinery battery at any time and selecting a suitable battery for work. It can predict the number of batteries to be used according to the work type and working duration of the next working day. The idle agricultural machinery garage is located next to the agricultural machinery battery storage module.

[0052] According to yet another aspect of the present invention, there is provided a bidirectional DC / DC converter based on a mutual charging device. The mutual charging device uses a bidirectional DC / DC converter to achieve charging of a battery with a lower voltage level by a battery with a higher voltage level, and charging of a battery with a higher voltage level by a battery with a lower voltage level. The converter includes a controllable power switch tube, enabling the converter to perform forward and reverse power transmission.

[0053] Compared with the prior art, the beneficial effects of this configuration method of electric agricultural machinery for large farms are as follows:

[0054] (1) Integrate agricultural machinery batteries with the rural comprehensive energy system, making full use of clean energy. At the same time, divide the management of agricultural machinery batteries into two stages: busy farming season and slack farming season. During the slack farming season, agricultural machinery batteries are connected to the rural energy system to absorb new energy, perform peak shaving and valley filling for the power grid, obtain benefits, and reduce carbon emissions in rural areas. During the busy farming season, the rural energy system fully guarantees the load of electric agricultural machinery, absorbs new energy while charging at a lower electricity price to respond to grid regulation, saves the operating cost of agricultural machinery, and improves the stability of the power grid.

[0055] (2) Establish an optimization model for agricultural machinery batteries to participate in the rural system, and optimize to obtain the best capacity suitable for the local rural comprehensive energy system, helping rural areas utilize new energy and reducing environmental pollution caused by fossil fuels. The optimization model takes economy and energy conservation as the optimization objectives, and uses different constraints such as agricultural machinery battery capacity constraints, system power balance constraints, investment constraints, agricultural machinery battery integrated station capacity constraints, and agricultural machinery battery integrated station quantity constraints.

[0056] (3) A comprehensive agricultural machinery battery station device is proposed to uniformly manage agricultural machinery batteries. The existing dispersed agricultural machinery batteries are not conducive to battery management. Storing agricultural machinery batteries in the comprehensive agricultural machinery battery station can increase battery life and performance through unified management. The comprehensive agricultural machinery battery station is divided into two parts: an agricultural machinery battery processing module and an agricultural machinery battery storage module. The agricultural machinery battery processing module analyzes data on the working type, working duration, and operating environment of agricultural machinery the next day to predict the load of agricultural machinery the next day. The agricultural machinery storage module facilitates the unified management and scheduling of agricultural machinery batteries. Description of the Drawings

[0057] Figure 1 Schematic diagram of the electric agricultural machinery battery management method provided by the present invention;

[0058] Figure 2 Shows the electric agricultural machinery battery management device provided by the present invention. Detailed Embodiments

[0059] The exemplary embodiments of the present invention will be described in detail below with reference to the drawings, where the same or similar reference numerals represent the same or similar elements. Additionally, in the following detailed description, for the sake of explanation, many specific details are set forth to provide a comprehensive understanding of the disclosed embodiments. However, it is obvious that one or more embodiments can also be implemented without these specific details. In other cases, well-known structures and devices are illustrated in a schematic manner to simplify the drawings.

[0060] Please refer to Figure 1 , the present invention provides an electric agricultural machinery battery management method, including: constructing an optimization model for agricultural machinery batteries to participate in the rural system, the optimization model taking economy and energy conservation as optimization goals, and the constraint conditions of the optimization model including: different agricultural machinery battery capacity constraints, system power balance constraints, investment constraints, agricultural machinery battery comprehensive station capacity constraints, and agricultural machinery battery comprehensive station quantity constraints; solving the optimization model to obtain the capacity of the agricultural machinery battery comprehensive station; and constructing a battery comprehensive station to participate in the operation of the rural energy system according to the optimal capacity.

[0061] The objective function related to economy in the optimization model includes the construction cost, operation and maintenance cost, and energy purchase cost of the electric agricultural machinery battery comprehensive station. The objective function is as follows:

[0062] min f1 = C inv + C opt - C out

[0063] In the formula, C inv is the annual investment cost of the battery comprehensive station, C opt is the operation and maintenance cost of the battery comprehensive station, C outFor the revenue of the battery integrated station.

[0064] The present invention plans and constructs the battery integrated station on an annual basis, optimizes it with the maximization of revenue as the optimization goal, and considers the construction cost and operation and maintenance cost of the agricultural machinery battery integrated station to plan the optimal capacity.

[0065] In the optimization model, the objective function related to carbon emissions includes the carbon emissions from purchasing electricity from the power grid and the carbon emissions reduced by using new energy. The objective function is as follows:

[0066] min f2 = T buy -T neg

[0067] In the formula, T buy is the carbon emissions from purchasing electricity from the power grid, and T neg is the carbon emissions reduced by using new energy.

[0068] The present invention considers the impact of electric agricultural machinery batteries connected to the rural integrated energy system on the carbon emissions of the entire system, and optimizes the optimal capacity with the minimum system carbon emissions as the optimization goal, which not only ensures the normal operation of the system but also ensures the environmental friendliness of the system.

[0069] The expressions for the annual investment cost of the agricultural machinery battery integrated station, the operation and maintenance cost of the agricultural machinery battery integrated station, the cost of purchasing electricity from the outside by the agricultural machinery battery integrated station, and the revenue of the battery integrated station are as follows:

[0070]

[0071]

[0072]

[0073] In the formula, c inv is the investment cost per unit capacity of the battery; X is the total configured capacity of the agricultural machinery battery; c mai is the annual operation and maintenance cost per unit capacity of the battery; y is the equipment life cycle; r is the discount rate; is the price of the system purchasing electricity from the power grid at time t; is the electricity purchase volume of the system in time period t; is the price of the system selling electricity to the power grid at time t; is the electricity sales volume of the system to the power grid in time period t.

[0074] The expression for the carbon emissions is:

[0075]

[0076]

[0077] In the formula, is the carbon emission coefficient of electric energy in the external power grid during period t; is the purchased electricity of the system during period t; is the electricity input from the rural new energy generator set to the agricultural machinery battery integrated station at time t.

[0078] The expression of the system power balance constraint is as follows:

[0079] P i (t) + P buy (t) + P d (t) = P load (t) + P loss (t) + P c (t)

[0080] In the formula, P i (t) is the power generation power of the conventional equipment in the rural energy system during period t; P buy (t) is the electricity purchased from the power grid by the system at time t, P c (t), P d (t) are the charge and discharge powers of the agricultural machinery battery integrated station at time t; P load (t) is the system electrical load at time t, P loss (t) is the active power loss of the system during period t. The present invention takes power balance as a constraint to ensure the normal operation of the system.

[0081] The expression of the investment constraint is as follows:

[0082] T max ≥ f in (n)

[0083] In the formula, T max is the maximum investment capacity of the agricultural machinery battery integrated station; f in (n) is the sum of the initial investments of the equipment in the agricultural machinery battery integrated station. The present invention takes the investment capacity as a constraint to ensure the interests of rural investors and establish the capacity of the agricultural machinery battery integrated station that conforms to the actual situation.

[0084] The expression of the planned area constraint is as follows:

[0085] xm ≤ S max

[0086] In the formula, m is the land area occupied by the installation of a single battery; S max is the available land area for building the integrated energy system. The present invention takes the planned area as a constraint to ensure that the capacity of the agricultural machinery battery integrated station conforms to the actual situation.

[0087] The expression of the agricultural machinery battery integrated station capacity constraint is as follows:

[0088] Ees,min ≤E es,m ≤E es,max

[0089] Wherein, E es,max and E es,min are respectively the upper and lower limits of the electrical energy stored in the batteries of the agricultural machinery battery integrated station.

[0090] The constraints related to the operation of the agricultural machinery battery also include:

[0091] 0 ≤ P c,t ≤ λ c,t P es,r (1)

[0092] 0 ≤ P d,t ≤ λ d,t P es,r (2)

[0093] λ c,t + λ d,t ≤ 1 (3)

[0094] P c,t · P d,t = 0 (4)

[0095] E es,t = E es,t-1 + (η c P c,t - P d,t / η d )· Δt (5)

[0096] The charging and discharging process of the agricultural machinery battery integrated station has the following constraints: the charging and discharging power cannot exceed its rated power value, as shown in formulas (1 - 3); it can only be in one of the charging, discharging or static states at a certain time period, as shown in formula (4); the electrical energy in the current time period is related to the charging and discharging efficiency, the charging and discharging power in the current time period, and the electrical energy in the previous time period, as shown in formula (5). Wherein, λ c,t and λ d,t respectively represent the 0 - 1 variables of the charging and discharging of the agricultural machinery battery at time t; P es,r is the rated power value of the agricultural machinery battery; E es,t and E es,t-1 are the electrical energies stored at time periods t and t - 1; η c and η d respectively represent the charging and discharging efficiencies of the energy storage. The present invention takes the operation of the agricultural machinery battery as a constraint to ensure the normal operation of the agricultural machinery battery integrated station.

[0097] The TOPSIS method is a commonly used comprehensive evaluation method that can make full use of the information of the original data, and its results can accurately reflect the gaps between various evaluation schemes. The first step is to normalize the original matrix, and the second step is to standardize the positive matrix, aiming to eliminate the influence of different dimensions. The third step is to calculate the scores and normalize them to find the optimal solution with the highest score.

[0098] Figure 2 It is an electric agricultural machinery battery management device. Using this device for electric agricultural machinery battery management, the agricultural machinery battery integrated station is divided into three parts: the agricultural machinery battery processing module, the agricultural machinery battery storage module, and the idle agricultural machinery garage. The agricultural machinery battery processing module analyzes the data of the next day's agricultural machinery work type, working hours, and operating environment to predict the next day's agricultural machinery load. The agricultural machinery storage module facilitates the unified management and scheduling of agricultural machinery batteries.

[0099] The electric agricultural machinery battery integrated station is close to the farm and the farmers' living areas. The agricultural machinery batteries are connected by cables and have fixed slots for easy access. At the same time, the electric agricultural machinery battery integrated station is connected to the rural energy system by cables so that each battery can participate in the operation of the rural integrated energy system as a whole. At the same time, there is a temperature control system in the agricultural machinery battery storage module to ensure that the batteries work at an appropriate temperature and improve the battery life.

[0100] The battery processing module in the agricultural machinery battery integrated station includes a processing system and a detection system, which can detect the life cycle of each agricultural machinery battery at any time and select suitable batteries for work. It can predict the number of batteries to be used according to the work type and working hours of the next working day, detect the power of each battery to facilitate whether to take it out for use, and output suitable batteries for use on the working day by inputting the work type and working hours of the next working day. The idle agricultural machinery garage is located next to the agricultural machinery battery storage module, facilitating the electric agricultural machinery to install batteries for work at any time.

[0101] Working principle: According to Figure 1 As shown, by collecting data such as the resource endowment, load characteristics, geographical location, and agricultural load of the planned location, as the prerequisite for the planning of the battery capacity of the electric agricultural machinery integrated station, it is optimized through an optimization algorithm. With economy and carbon emissions as the optimization objectives, and system power balance, investment constraints, planned area, agricultural machinery battery integrated station capacity, and agricultural machinery battery operation as constraints, a Pareto frontier graph of the economy and carbon emissions of different plans is planned. The TOPSIS method principle is applied to study the Pareto frontier site selection obtained by solving the multi-objective optimization problem, and weights are set to obtain the best capacity of the best agricultural machinery battery integrated station. By Figure 2As shown in the figure, an electric agricultural machinery battery management device is established. The battery storage module is managed by the battery processing module, and the battery temperature, power, and usage duration are detected by the detection system so that unhealthy batteries can be replaced at any time. The power of each battery is detected to facilitate whether to take it out for use, and the temperature of the battery storage can be controlled through the temperature control system. At the same time, the processing system can predict the number of batteries to be used according to the work type and work duration of the next working day. By inputting the work type and work duration of the next working day, suitable batteries are output for use on the working day.

[0102] Compared with the prior art, the beneficial effects of this configuration method of large farm electric agricultural machinery are as follows:

[0103] (1) Integrate the agricultural machinery battery with the rural integrated energy system, making full use of clean energy. At the same time, the management of agricultural machinery batteries is divided into two stages: busy farming season and slack farming season. During the slack farming season, the agricultural machinery battery is connected to the rural energy system to absorb new energy, perform peak shaving and valley filling on the power grid, obtain benefits, and at the same time reduce the carbon emissions in rural areas. During the busy farming season, the rural energy system fully guarantees the load of electric agricultural machinery, absorbs new energy while charging at a lower electricity price to respond to the grid regulation, saves the operation cost of agricultural machinery, and improves the stability of the power grid.

[0104] (2) Establish an optimization model for agricultural machinery batteries to participate in the rural system, and optimize to obtain the best capacity suitable for the local rural integrated energy system, helping rural areas utilize new energy, reducing environmental pollution caused by fossil fuels. The optimization model takes economy and energy conservation as the optimization goals, and takes different agricultural machinery battery capacity constraints, system power balance constraints, investment constraints, agricultural machinery battery integrated station capacity constraints, agricultural machinery battery integrated station quantity constraints, etc. as constraint conditions.

[0105] (3) Propose an agricultural machinery battery integrated station device to uniformly manage agricultural machinery batteries. The existing agricultural machinery batteries are scattered, which is not conducive to battery management. Store agricultural machinery batteries in the agricultural machinery battery integrated station. Through unified management, the battery life and performance are increased. The agricultural machinery battery integrated station is divided into two parts: the agricultural machinery battery processing module and the agricultural machinery battery storage module. The agricultural machinery battery processing module analyzes the data of the next day's agricultural machinery work type, work duration, and working environment to predict the next day's agricultural machinery load. The agricultural machinery storage module facilitates the unified management and scheduling of agricultural machinery batteries.

[0106] The comprehensive energy system configuration method considering the DC / DC connection of electric agricultural machinery provided by the present invention takes into account the electric energy substitution of agricultural machinery and the comprehensive energy system in large farms, and is a configuration method for energy storage connected by DC / DC. This method includes: constructing an optimization planning model for agricultural machinery batteries to participate in the rural system, and optimizing to obtain the optimal capacity of agricultural machinery batteries suitable for the local rural energy system; the optimization model takes economy and carbon emissions as optimization objectives; the model constraints include system power balance constraints, investment constraints, constraints on the planned area, constraints on the capacity of the agricultural machinery battery integrated station, and constraints related to the operation of agricultural machinery batteries; solving the optimization model to obtain the capacity of the agricultural machinery battery integrated station; according to the solved optimal capacity, constructing a battery integrated station to participate in the operation of the rural energy system through a DC / DC converter. At the same time, an agricultural machinery battery integrated station device is provided, which is divided into three parts: an agricultural machinery battery processing and detection module, an agricultural machinery battery storage module, and an idle agricultural machinery garage. The agricultural machinery battery processing and detection module calculates the next-day agricultural machinery load by analyzing data such as the next-day agricultural machinery work type, working hours, and operating environment; the agricultural machinery battery storage module is an agricultural machinery battery storage library and a temperature control system; the management of electric agricultural machinery batteries is divided into busy farming and slack farming stages. The agricultural machinery batteries are connected to the rural energy system through DC / DC. In the slack farming stage, the agricultural machinery batteries are connected to the rural energy system to consume new energy, perform peak shaving and valley filling on the power grid, obtain benefits, and at the same time reduce the carbon emissions in rural areas; in the busy farming stage, the rural energy system fully guarantees the electric agricultural machinery load, consumes new energy and charges at a lower electricity price to respond to the grid regulation. Different power-level agricultural machinery power supplies are compatible with the communication architecture and interfaces, and the interaction between the agricultural machinery batteries and the rural power grid is realized by using a BMS system and a DC / DC converter. The energy storage or energy storage space of the power batteries of electric agricultural machinery is used to regulate the energy of the rural energy station, which can not only effectively regulate the rural energy station, but also improve the utilization rate of the power batteries of agricultural machinery and reduce resource waste.

[0107] In the present invention, a bidirectional DC / DC converter based on a mutual charging device is also provided. The voltage levels of the batteries are not particularly different from each other. Considering factors such as cost and portability, when designing, a non-isolated DC / DC can fully meet the step-up or step-down requirements. Without a transformer, the circuit structure is not complex, the device volume is small and the cost is low, and each component is directly electrically connected, avoiding additional energy loss, and the working efficiency is relatively high. It is widely used in occasions where electrical isolation is not required.

[0108] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes may be made therein without departing from the principles and spirit of the present invention. The scope of application of the present invention is defined by the appended claims and their equivalents.

Claims

1. A comprehensive energy system configuration method considering the connection of electric agricultural machinery DC / DC, characterized in that, The method includes: Construct an optimization model for agricultural machinery batteries to participate in the rural system. The optimization model takes economy and carbon emissions as optimization objectives. The constraint conditions of the optimization model include: different agricultural machinery battery capacity constraints, system power balance constraints, investment constraints, agricultural machinery battery integrated station capacity constraints, and agricultural machinery battery integrated station quantity constraints; Solve the optimization model to obtain the capacity of the agricultural machinery battery integrated station; According to the solved optimal capacity, build a battery integrated station to participate in the operation of the rural energy system.

2. The comprehensive energy system configuration method considering the connection of electric agricultural machinery DC / DC according to claim 1, characterized in that: The objective function related to economy in the optimization model includes the construction cost, operation and maintenance cost, and energy purchase cost of the electric agricultural machinery battery integrated station; the objective function is as follows: min f1=C inv +C opt -C out where C inv is the annual investment cost of the battery integrated station, C opt is the operation and maintenance cost of the battery integrated station, and C out is the revenue of the battery integrated station; The objective function related to carbon emissions in the optimization model includes the carbon emissions from purchasing electricity from the power grid and the carbon emissions reduced by using new energy; the objective function related to carbon emissions is as follows: min f2 = T buy -T neg where T buy is the carbon emission of electricity purchased from the power grid, and T neg is the carbon emission reduced by using new energy.

3. The integrated energy system configuration method considering the connection of electric agricultural machinery DC / DC according to claim 2, characterized in that: The expressions for the annual investment cost of the battery integrated station, the operation and maintenance cost of the battery integrated station, and the revenue of the battery integrated station are respectively: Where c inv is the investment cost per unit capacity of the battery; X is the total configured capacity of the agricultural machinery battery; c mai is the annual operation and maintenance cost per unit capacity of the battery; y is the equipment life cycle; r is the discount rate; is the price at which the system purchases electricity from the power grid at time t; is the electricity purchase quantity of the system in period t; is the price at which the system sells electricity to the power grid at time t; is the grid-connected electricity quantity of the system in period t.

4. The integrated energy system configuration method considering the connection of electric agricultural machinery DC / DC according to claim 2, characterized in that: The expression for carbon emissions is: In the formula, is the carbon emission coefficient of electric energy in the external power grid during the t period; is the purchased electricity of the system during the t period, is the electricity input from the rural new energy generator set to the agricultural machinery battery integrated station at the t moment.

5. The comprehensive energy system configuration method for considering the DC / DC connection of electric agricultural machinery according to any one of claims 1 to 4, characterized in that, The expression for the system power balance constraint is as follows: P i (t) + P buy (t) + P d (t) = P load (t) + P loss (t) + P c (t) Where, P i (t) is the power generation of conventional equipment in the rural energy system during the time period t; P buy (t) is the electricity purchased from the power grid by the system at time t, P c (t), P d (t) are the charging and discharging powers of the agricultural machinery battery integrated station at time t; P load (t) is the electrical load of the system at time t, P loss (t) is the active power loss of the system during the time period t; The expression for the investment constraint is as follows: T max ≥ f in (n) where T max is the maximum investment capacity of the agricultural machinery battery comprehensive station; f in (n) is the sum of the initial investments of the equipment in the agricultural machinery battery comprehensive station; The expression for the constraint of the planned area is as follows: xm≤S max where m is the land area occupied by the installation of a single battery; S max is the available land area for building the integrated energy system; The expression for the agricultural machinery battery integrated station capacity constraint is as follows: E es，min ≤E es，m ≤E es，max where E es，max and E es，min are the upper and lower limits of the electrical energy stored in the batteries of the agricultural machinery battery integrated station, respectively; The constraints related to the operation of agricultural machinery batteries also include: 0 ≤ P c，t ≤ λ c，t P es，r (1) 0 ≤ P d，t ≤ λ d，t P es，r (2) λ c，t +λ d，t ≤1 (3) P c，t ·P d，t = 0 (4) E es，t = E es，t-1 + (η c P c，t - P d，t / η d )·Δt (5) The charging and discharging process of the agricultural machinery battery integrated station has the following constraints: the charging and discharging power shall not exceed the rated power value, as required by formulas (1)-(3); it can only be in one of the charging, discharging, or static states at a certain time period, as required by formula (4); the electric energy in the current time period, the charging and discharging efficiency, the charging and discharging power in the current time period, and the electric energy in the previous time period shall meet the requirements of formula (5); where λ c，t and λ d，t respectively represent the 0-1 variables of the charging and discharging of the agricultural machinery battery at time t; E es，t and E es，t-1 are the electrical energies stored in time periods t and t-1; η c and η d respectively represent the charge-discharge efficiency of energy storage.

6. An electric agricultural machinery battery management method, characterized in that: The agricultural machinery battery integrated station is divided into three parts: an agricultural machinery battery detection and processing module, an agricultural machinery battery storage module, and an idle agricultural machinery garage; the agricultural machinery battery detection and processing module calculates the next-day agricultural machinery load by analyzing the data of the next-day agricultural machinery work type, working hours, and operating environment, and the agricultural machinery battery storage module facilitates the unified management and scheduling of agricultural machinery batteries.

7. The electric agricultural machinery battery management method according to claim 6, characterized in that: The agricultural machinery battery integrated station is close to the farm and the farmer living area. The agricultural machinery batteries are connected by cables and are provided with fixed slots for easy access to the agricultural machinery batteries. At the same time, the agricultural machinery battery integrated station is connected to the rural energy system by cables, and a temperature control system is provided in the agricultural machinery battery storage module.

8. The electric agricultural machinery battery management device according to claim 7, characterized in that: The agricultural machinery battery integrated station includes a processor and a detector, which are used to detect the life cycle of each agricultural machinery battery at any time and select appropriate batteries for work, and can predict the number of batteries to be used according to the work type and working hours of the next working day. The idle agricultural machinery garage is located next to the agricultural machinery battery storage module.

9. A bidirectional DC / DC converter based on a mutual charging device, characterized in that: The mutual charging device uses a bidirectional DC / DC converter to realize charging from a battery with a higher voltage level to a battery with a lower voltage level, and charging from a battery with a lower voltage level to a battery with a higher voltage level. The converter includes a controllable power switch tube to enable the converter to perform forward and reverse power transmission.

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