An efficiency-based energy storage system operation cost optimization control method and terminal

Abstract

The present invention relates to the technical field of power system control, and in particular to an efficiency-based energy storage system operating cost optimization control method and terminal. For a microgrid system, an efficiency function including temperature is established for PCS and DC / DC, and a target function and a power balance constraint condition are constructed with real-time operating cost as the target; the efficiency data of the battery is obtained, and according to the efficiency function of the PCS and DC / DC, the efficiency data of the PCS and DC / DC at different temperature points are obtained; the temperature data and power data of the PCS and DC / DC are obtained in real time, and the target efficiency data corresponding to the battery, PCS and DC / DC are obtained according to the temperature data fitting; the target efficiency data is substituted into the target function and solved, and optimization control is performed according to the solution result; the present invention optimizes and controls the energy storage system and reduces the operating cost of the energy storage system.

Description

Technical Field

[0001] The present invention relates to the technical field of power system control, and in particular to an efficiency-based energy storage system operating cost optimization control method and terminal. Background Art

[0002] The DC distribution network has broad development prospects in the future power system due to its advantages of low line loss, high power supply reliability, easy access to distributed power sources and energy storage devices, excellent power quality, environmental protection and low equipment investment. At the same time, with the continuous advancement of technology and the continuous promotion of policies, the DC distribution network will achieve large-scale, intelligent, standardized and flexible development.

[0003] The basic components of a DC microgrid are lithium-ion batteries or other types of energy storage batteries, photovoltaics, energy storage converters PCS, DC / DC converters, DC loads, and energy management systems. Load DCization, converter flexible DC networking, and intelligent energy management and optimization control are the core and development trends of this type of power grid system. For photovoltaic storage and charging systems, the main direction of optimization control is the effective use of energy and orderly charging. For scenarios with relatively fixed loads, such as daily power loads in industrial and commercial energy storage, the main purpose of energy management and regulation is to efficiently allocate the proportion of AC power supply and dispatch the power supply of photovoltaics and different groups of energy storage batteries. With the maturity of battery thermal management technology, in systems that generally contain the above-mentioned power units, the operating temperature of the battery can be controlled in a high-efficiency zone with less fluctuations through liquid cooling thermal management. However, in situations where the economic efficiency of the equipment is relatively high, various power converters still need to adopt air cooling to dissipate heat. In the absence of constant temperature control in the electrical compartment, the temperature inside the electrical compartment and the temperature of the main radiator of the converter will vary greatly under different climatic conditions, load conditions, and heat dissipation conditions. The average temperature of the converter at different installation locations in the same electrical compartment also varies considerably.

[0004] In the common industrial and commercial energy storage scenario where DC loads are the main loads, batteries, photovoltaics and AC power grids jointly supply power to the loads. In a topology with multiple battery clusters or battery strings and multiple PCS strings that can be independently controlled, the output power of each battery string through DC / DC and the DC output power of PCS are dispatched through the energy management system, generally based on the battery status. Against the background of gradually improving independent thermal management of batteries and battery consistency, factors such as differences in converter efficiency and differences in electrical compartment temperature have gradually become apparent in their impact on operating economy. A method is needed to control the power output of each converter using an optimization method based on the logic of peak and valley regulation of electricity prices, after considering the impact of converter efficiency differences on operating economic indicators. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an efficiency-based energy storage system operating cost optimization control method and terminal to optimize the operating cost of the energy storage system.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] An efficiency-based energy storage system operating cost optimization control method comprises the following steps:

[0008] S1. For the microgrid system, establish efficiency functions including temperature for PCS and DC / DC, and construct objective functions and power balance constraints with real-time operation cost as the target;

[0009] S2. Obtaining efficiency data of the battery, and obtaining efficiency data of the PCS and DC / DC at different temperature points according to the efficiency functions of the PCS and DC / DC;

[0010] S3, acquiring temperature data and power data of the PCS and DC / DC in real time, and acquiring target efficiency data corresponding to the battery, PCS and DC / DC according to the temperature data;

[0011] S4. Substituting the target efficiency data into the target function and solving it, and performing optimization control according to the solution result.

[0012] In order to solve the above technical problems, another technical solution adopted by the present invention is:

[0013] An efficiency-based energy storage system operating cost optimization control terminal includes a processor, a memory, and a computer program stored in the memory and executable on the processor. When the processor executes the computer program, the steps in the above-mentioned efficiency-based energy storage system operating cost optimization control method are implemented.

[0014] The beneficial effects of the present invention are as follows: an efficiency-based energy storage system operating cost optimization control method and terminal of the present invention considers the different operating efficiencies of PCS and DC / DC at different temperatures, establishes an efficiency function including temperature for PCS and DC / DC, and takes real-time operating cost as the target, constructs an objective function and power balance constraints, and solves the objective function based on the real-time operating conditions, thereby optimizing the control of the energy storage system and reducing the operating cost of the energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 A flowchart of an efficiency-based energy storage system operating cost optimization control method according to an embodiment of the present invention;

[0016] Figure 2A specific flow chart of an efficiency-based energy storage system operating cost optimization control method according to an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of the structure of a power system exemplified by an embodiment of the present invention;

[0018] Figure 4 A structural diagram of an energy storage system operating cost optimization control terminal based on efficiency according to an embodiment of the present invention;

[0019] Description of labels:

[0020] 1. An efficiency-based energy storage system operation cost optimization control terminal; 2. Processor; 3. Memory. DETAILED DESCRIPTION

[0021] In order to explain the technical content, achieved objectives and effects of the present invention in detail, the following is an explanation in combination with the implementation modes and the accompanying drawings.

[0022] Please refer to Figure 1 as well as Figure 2 , an efficiency-based energy storage system operation cost optimization control method, comprising the steps of:

[0023] S1. For the microgrid system, establish efficiency functions including temperature for PCS and DC / DC, and construct objective functions and power balance constraints with real-time operation cost as the target;

[0024] S2. Obtaining efficiency data of the battery, and obtaining efficiency data of the PCS and DC / DC at different temperature points according to the efficiency functions of the PCS and DC / DC;

[0025] S3, acquiring temperature data and power data of the PCS and DC / DC in real time, and acquiring target efficiency data corresponding to the battery, PCS and DC / DC according to the temperature data;

[0026] S4. Substituting the target efficiency data into the target function and solving it, and performing optimization control according to the solution result.

[0027] From the above description, it can be seen that the beneficial effects of the present invention are: an efficiency-based energy storage system operating cost optimization control method of the present invention takes into account the different operating efficiencies of PCS and DC / DC at different temperatures, establishes an efficiency function including temperature for PCS and DC / DC, and takes real-time operating cost as the target, constructs an objective function and power balance constraints, and solves the objective function based on the real-time operating conditions, thereby optimizing the control of the energy storage system and reducing the operating cost of the energy storage system.

[0028] Furthermore, the construction of the objective function includes the steps of:

[0029] When all PCSs are rectified output and all batteries are discharged, within the set control interval D, there is an objective function of real-time operating cost:

[0030] ;

[0031] in, is the cost of getting energy from the grid, is the cost of getting energy from the battery.

[0032] From the above description, it can be seen that the real-time operation cost consists of the cost of obtaining energy from the grid and the cost of obtaining energy from the battery.

[0033] Furthermore, the cost of obtaining energy from the grid The determination includes:

[0034] ;

[0035] is the output power in the rectified direction of the jth PCS, is the real-time efficiency of the jth PCS, expressed as a function based on temperature and output power:

[0036] ;

[0037] is the real-time grid electricity price, and N is the number of PCSs.

[0038] From the above description, it can be seen that the cost of obtaining energy from the power grid needs to consider the PCS output power and the efficiency of the PCS, while the operating efficiency of the PCS needs to consider the operating temperature of the PCS.

[0039] Furthermore, the cost of obtaining energy from batteries The determination includes:

[0040] ;

[0041] is the output power of the i-th DC / DC, is the real-time efficiency of the i-th DC / DC, expressed as a function based on temperature and output power:

[0042] ;

[0043] and are the charging efficiency and discharging efficiency of the ith battery, and are the battery temperature and accumulated discharge capacity Function:

[0044] ;

[0045] ;

[0046] is the grid electricity price during off-peak hours. is the average efficiency of the i-th DC / DC at a certain charging rate under battery charging conditions, and M is the number of DC / DCs, corresponding to the number of batteries.

[0047] From the above description, it can be seen that the cost of obtaining energy from the battery also needs to consider the output power and efficiency of the DC / DC, as well as the charging efficiency and discharging efficiency of the battery itself.

[0048] Furthermore, the construction of the power balance constraint condition comprises the steps of:

[0049] To meet the DC load The power requirement is subject to the following constraints:

[0050] ;

[0051] in, It is the sum of all photovoltaic input power on the DC bus. is the output power of the ith DC / DC, is the output power in the rectification direction of the jth PCS, N is the number of PCSs, and M is the number of DC / DCs, which corresponds to the number of batteries.

[0052] From the above description, it can be seen that the sum of the DC output power of all M DC / DCs and the sum of the rectified output power of all N PCSs is equal to the difference between the DC load power and the photovoltaic power.

[0053] Furthermore, obtaining the battery efficiency includes the steps of:

[0054] For each model of the M batteries, obtain the initial life span of the model based on the test data. and end of life In both states, and the operating temperature is Charging efficiency value under And the discharge efficiency value ; Interpolate the charging efficiency value and the discharging efficiency value to obtain the efficiency matrix of each battery:

[0055] ;

[0056] .

[0057] From the above description, it can be seen that for batteries used in energy storage, they must undergo performance tests that meet national standards, including charging and discharging efficiency tests, or obtain them through type tests by suppliers. At present, energy storage batteries mainly use liquid cooling thermal management methods, which can always control the battery operating temperature within a small temperature range, and the efficiency within this range does not change much. Therefore, the average value of the battery operating temperature is set to control , the efficiency parameter is obtained by testing the battery at this temperature. The testing principle is the same at the initial state of the battery life and at the end of the life.

[0058] Furthermore, the efficiency data of PCS and DC / DC at different temperature points are obtained including:

[0059] The data matrix of the efficiency of each model of PCS and DC / DC at x power points is tested under the condition that the main heat sink temperature of PCS and DC / DC converter can be adjusted at y temperature points. and :

[0060] ;

[0061] .

[0062] From the above description, it can be seen that under the condition that the main heat sink temperature of the PCS and DC / DC converter can be adjusted at y temperature points, the data matrix of the output x power point efficiency of each model is tested and , which is the discretized value of f1 and f2 mentioned above.

[0063] Further, step S3 includes:

[0064] Each PCS and DC / DC has different installation positions and heat dissipation conditions, resulting in different operating temperatures, which leads to efficiency differences. By setting the control interval D, the main heat sink temperature and output power of N PCS and M DC / DC at time t are obtained to form a data matrix:

[0065] , ;

[0066] , ;

[0067] And the efficiency value matrix of each PCS and DC / DC of each model at time t is obtained by interpolation method:

[0068] ;

[0069] .

[0070] From the above description, it can be seen that by acquiring the temperature and output power of the PCS and DC / DC at the same time, a temperature and power data matrix is ​​established, and a corresponding efficiency matrix is ​​obtained.

[0071] Further, step S4 includes:

[0072] Substituting the target efficiency data into the objective function and solving it through an optimization algorithm;

[0073] Perform optimization control based on the solution results.

[0074] From the above description, it can be seen that the objective function is solved by the optimization algorithm, thereby performing optimization control.

[0075] Please refer to Figure 4 , an efficiency-based energy storage system operating cost optimization control terminal, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above-mentioned efficiency-based energy storage system operating cost optimization control method when executing the computer program.

[0076] The efficiency-based energy storage system operating cost optimization control method and terminal of the present invention are suitable for the operating cost optimization control of the energy storage system, and are particularly suitable for the operating cost optimization control of a direct current-conforming microgrid system.

[0077] Please refer to Figure 1 and Figure 2 , Embodiment 1 of the present invention is:

[0078] An efficiency-based energy storage system operating cost optimization control method comprises the following steps:

[0079] S1. For the microgrid system, an efficiency function including temperature is established for PCS and DC / DC, and the objective function and power balance constraints are constructed with real-time operating cost as the target.

[0080] In this embodiment, the efficiency of N PCS is assumed to be , efficiency of M DC / DC , assuming that the bidirectional efficiency of each DC / DC is the same (when the bidirectional efficiency of the DC / DC is different, it does not affect the implementation of the control method of this case).

[0081] In this embodiment, M batteries correspond to M DC / DCs one by one, and it is assumed that the charging efficiency and discharging efficiency of each battery are inversely proportional to the accumulated discharge capacity of the battery (ie, the efficiency decreases after the battery ages).

[0082] Assume that the battery is only charged during valley electricity prices and can be discharged during non-valley electricity times; the charging efficiency of M batteries is , discharge efficiency .

[0083] The construction of the objective function comprises the steps of:

[0084] When all PCSs are rectified output and all batteries are discharged, within the set control interval D, there is an objective function of real-time operating cost:

[0085] ;

[0086] in, is the cost of getting energy from the grid, is the cost of getting energy from the battery;

[0087] The cost of getting energy from the grid The determination includes:

[0088] ;

[0089] is the output power in the rectified direction of the jth PCS, is the real-time efficiency of the jth PCS, expressed as a function based on temperature and output power:

[0090] ;

[0091] is the real-time grid electricity price, and N is the number of PCSs.

[0092] The cost of getting energy from batteries The determination includes:

[0093] ;

[0094] is the output power of the ith DC / DC, is the real-time efficiency of the i-th DC / DC, expressed as a function based on temperature and output power:

[0095] ;

[0096] and are the charging efficiency and discharging efficiency of the ith battery, and are the battery temperature and accumulated discharge capacity Function:

[0097] ;

[0098] ;

[0099] is the grid electricity price during off-peak hours. is the average efficiency of the i-th DC / DC at a certain charging rate under battery charging conditions, and M is the number of DC / DCs, corresponding to the number of batteries.

[0100] The construction of the power balance constraint condition comprises the steps of:

[0101] To meet the DC load The power requirement is subject to the following constraints:

[0102] ;

[0103] in, It is the sum of all photovoltaic input power on the DC bus. is the output power of the ith DC / DC, is the output power in the rectification direction of the jth PCS, N is the number of PCSs, and M is the number of DC / DCs, which corresponds to the number of batteries.

[0104] This formula means that the sum of the DC output power of all M DC / DCs and the sum of the rectified output power of all N PCSs is equal to the difference between the DC load power and the photovoltaic power.

[0105] S2. Obtaining efficiency data of the battery, and according to the efficiency functions of the PCS and DC / DC, obtaining efficiency data of the PCS and DC / DC at different temperature points.

[0106] In this embodiment, for a microgrid system, all N PCSs, all M DC / DCs, and M batteries may have different models.

[0107] The acquisition of battery efficiency includes the following steps:

[0108] For each model of the M batteries, obtain the initial life span of the model based on the test data. and end of life In both states, and the operating temperature is Charging efficiency value under And the discharge efficiency value ; Interpolate the charging efficiency value and the discharging efficiency value to obtain the efficiency matrix of each battery:

[0109] ;

[0110] .

[0111] Note: (1) For batteries used in energy storage, they must undergo performance tests that meet national standards, including charging and discharging efficiency tests, or obtain them through type tests by suppliers. Currently, energy storage batteries mainly use liquid cooling thermal management methods, which can always control the battery operating temperature within a small temperature range, and the efficiency within this range does not change much. In this embodiment, the average battery operating temperature is controlled within , to obtain the efficiency parameters, that is, the battery is tested at this temperature.

[0112] (2) The efficiency test in (1) above is the test value at the initial state of life. The same test is performed at the end of life to obtain the test value.

[0113] Obtaining PCS and DC / DC efficiency data at different temperature points includes:

[0114] The data matrix of the efficiency of each model of PCS and DC / DC at x power points is tested under the condition that the main heat sink temperature of PCS and DC / DC converter can be adjusted at y temperature points. and :

[0115] ;

[0116] .

[0117] The number of x and y is determined according to the test conditions.

[0118] If the system contains 2 types of PCS and 2 types of DC / DC, 2 corresponding efficiency data matrices are obtained.

[0119] In this embodiment, the tested efficiency matrix data is stored in the memory of the microgrid energy management system.

[0120] S3. Acquire temperature data and power data of the PCS and DC / DC in real time, and acquire target efficiency data corresponding to the battery, PCS and DC / DC according to the temperature data.

[0121] In this embodiment, by acquiring the temperature and power data of the operating PCS and DC / DC, the efficiency of the operating point is fitted according to the stored data, and the real-time cost objective function is brought into the operation, and the PCS and DC / DC operating power that minimizes the objective function value is obtained through the optimization algorithm and controlled in real time, so that the real-time operation cost of the system is minimized. Each PCS and DC / DC has different installation locations and heat dissipation conditions, especially for systems with air-cooled power converters, and different operating temperatures lead to efficiency differences.

[0122] Step S3 includes:

[0123] Each PCS and DC / DC has different installation positions and heat dissipation conditions, resulting in different operating temperatures, which leads to efficiency differences. By setting the control interval D, the main heat sink temperature and output power of N PCS and M DC / DC at time t are obtained to form a data matrix:

[0124] , ;

[0125] , ;

[0126] And the efficiency value matrix of each PCS and DC / DC of each model at time t is obtained by interpolation method:

[0127] ;

[0128] .

[0129] S4, substituting the target efficiency data into the target function and solving it, and performing optimization control according to the solution result;

[0130] Step S4 includes:

[0131] Substituting the target efficiency data into the objective function and solving it through an optimization algorithm;

[0132] Perform optimization control based on the solution results.

[0133] In this embodiment, the goal is to minimize the real-time operation cost objective function at time t, and solve the problem of , The given value of .

[0134] Objective function:

[0135] ;

[0136] Constraints:

[0137] ;

[0138] , ;

[0139] in, , are the power limit values ​​of the converters respectively.

[0140] Initial conditions:

[0141] .

[0142] Please refer to Figure 3 , Embodiment 2 of the present invention is:

[0143] In this embodiment, an efficiency-based energy storage system operating cost optimization control method described in the above embodiment 1 is illustrated.

[0144] Features Figure 3 In the power system shown, the number of PCSs N=2, of the same model, with a single power limit of 150kW; the number of DC / DCs M=2, of the same model, with a single power limit of 120kW; the total output power of the photovoltaic power generation unit at time t is 50kW, and the DC load power is 500kW; the two batteries are of the same model; the off-peak electricity price is taken =0.4 / kWh, real-time grid electricity price within the control interval =0.8 / kWh.

[0145] Thermal management controls the battery operating temperature Under the condition, assuming that the two batteries have the same efficiency at the beginning and end of life: =[0.970, 0.970; 0.905, 0.905]; =[0.975, 0.975; 0.915, 0.915]; Get the PCS and DC / DC efficiency test matrix at 4 temperatures and ; The cumulative discharge capacity of the two batteries is set to 0 and 2×e5kwh respectively, and the cumulative discharge capacity at the end of life is set to 1×e6kwh; The interpolation method is used to obtain the charge / discharge efficiency in the two battery control intervals, which are 0.9700, 0.9570 and 0.9750, 0.9630 respectively.

[0146] Note: The efficiency values ​​are examples and do not represent actual test results.

[0147] Assume that the operating power of the two PCSs at time t is:

[0148] =[127,122]kW;

[0149] The temperature is:

[0150] =[38,10];

[0151] The operating power of DC / DC is:

[0152] =[105,108]kW;

[0153] The temperature is:

[0154] =[0,10].

[0155] Satisfy the constraints:

[0156] ;

[0157] , .

[0158] Note: The temperature values ​​are for calculation examples and do not represent actual operating results.

[0159] The efficiency value matrix of each of the two PCSs and DC / DC at time t is obtained by the interpolation method.

[0160] =[0.9497,0.9508];

[0161] =[0.9528,0.9493];

[0162] Note: The efficiency value is the calculation result based on the example; the interpolation method is not limited. In this embodiment, the "spline" method can be used to fit the efficiency function and obtain the interpolation value.

[0163] Taking the control interval D as 60s, using the above data at time t, using the neural network optimization algorithm, the power that minimizes the real-time operation cost objective function in the t+1 period is calculated as:

[0164] =[61.37,149.48]kW;

[0165] = [120.00,119.15]kW;

[0166] = 4.8867 yuan / 60s.

[0167] In contrast, at time t+1, the calculation is still based on the 3 initial conditions without optimization. =5.2069 yuan / 60s.

[0168] Embodiment 3 of the present invention is:

[0169] An efficiency-based energy storage system operating cost optimization control terminal 1 includes a processor 2, a memory 3, and a computer program stored in the memory 3 and executable on the processor 2. When the processor 2 executes the computer program, the steps in the efficiency-based energy storage system operating cost optimization control method described in the above embodiment one or two are implemented.

[0170] In summary, the present invention provides an efficiency-based energy storage system operating cost optimization control method and terminal, which takes into account the different operating efficiencies of PCS and DC / DC at different temperatures, establishes an efficiency function including temperature for PCS and DC / DC, and takes real-time operating cost as the target to construct an objective function and power balance constraints, and solves the objective function based on the real-time operating conditions, thereby optimizing the control of the energy storage system and reducing the operating cost of the energy storage system.

[0171] The present invention is based on the efficiency optimization of the string energy storage system control method. Under the condition of considering the temperature inconsistency, the high-efficiency converter increases the output, so that the operating cost is optimized. In the period of high electricity price and small load fluctuation during the peak and valley electricity price, the electricity cost is minimized by this method.

[0172] At the same time, the impact of battery efficiency at different lifespans on operating costs is taken into consideration. The algorithm can automatically balance the discharge power of batteries at different lifespan stages, optimize the utilization rate of battery assets, and make the battery life measured by Leijie power meter more consistent.

[0173] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent transformations made using the contents of the present invention's specification and drawings, or directly or indirectly applied in related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. An efficiency-based energy storage system operating cost optimization control method, characterized in that: Includes steps: S1. For the microgrid system, establish efficiency functions including temperature for PCS and DC / DC, and construct objective functions and power balance constraints with real-time operation cost as the target; The objective function is constructed as follows: When all PCSs are rectified output and all batteries are discharged, within the set control interval D, the objective function of the real-time operation cost is: ； in, is the cost of getting energy from the grid, is the cost of getting energy from the battery; The cost of getting energy from batteries The determination includes: ； is the output power of the ith DC / DC, is the real-time efficiency of the i-th DC / DC, expressed as a function based on temperature and output power: ； and are the charging efficiency and discharging efficiency of the ith battery, and are the battery temperature and accumulated discharge capacity Function: ； ； is the grid electricity price during off-peak hours. is the average efficiency of the i-th DC / DC at a certain charging rate under battery charging conditions, M is the number of DC / DCs, corresponding to the number of batteries; S2. Obtaining efficiency data of the battery, and obtaining efficiency data of the PCS and DC / DC at different temperature points according to the efficiency functions of the PCS and DC / DC; S3, acquiring temperature data and power data of the PCS and DC / DC in real time, and acquiring target efficiency data corresponding to the battery, PCS and DC / DC according to the temperature data; S4. Substituting the target efficiency data into the target function and solving it, and performing optimization control according to the solution result.

2. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: The cost of getting energy from the grid The determination includes: ； is the output power in the rectified direction of the jth PCS, is the real-time efficiency of the jth PCS, expressed as a function based on temperature and output power: ； is the real-time grid electricity price, and N is the number of PCSs.

3. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: The construction of the power balance constraint condition comprises the steps of: To meet the DC load The power requirement is subject to the following constraints: ； in, It is the sum of all photovoltaic input power on the DC bus. is the output power of the ith DC / DC, is the output power in the rectification direction of the jth PCS, N is the number of PCSs, and M is the number of DC / DCs, which corresponds to the number of batteries.

4. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: The acquisition of battery efficiency includes the following steps: For each model of the M batteries, obtain the initial life span of the model based on the test data. and end of life In both states, and the operating temperature is Charging efficiency value under And the discharge efficiency value ; Interpolate the charging efficiency value and the discharging efficiency value to obtain the efficiency matrix of each battery: ； 。 5. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: Obtaining PCS and DC / DC efficiency data at different temperature points includes: The data matrix of the efficiency of each model of PCS and DC / DC at x power points is tested under the condition that the main heat sink temperature of PCS and DC / DC converter can be adjusted at y temperature points. and : ； 。 6. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: Step S3 includes: Each PCS and DC / DC has different installation positions and heat dissipation conditions, resulting in different operating temperatures, which leads to efficiency differences. By setting the control interval D, the main heat sink temperature and output power of N PCS and M DC / DC at time t are obtained to form a data matrix: ， ； ， ； And the efficiency value matrix of each PCS and DC / DC of each model at time t is obtained by interpolation method: ； 。 7. The method for optimizing the operation cost of an energy storage system based on efficiency according to claim 1, characterized in that: Step S4 includes: Substituting the target efficiency data into the objective function and solving it through an optimization algorithm; Perform optimization control based on the solution results.

8. An efficiency-based energy storage system operation cost optimization control terminal, comprising a processor, a memory, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, the steps in the efficiency-based energy storage system operating cost optimization control method described in any one of claims 1 to 7 are implemented.

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