Multi-unit operation control optimization method and device connected to gravity energy storage

Abstract

The present invention discloses a method and device for optimizing the operation control of multiple units connected to gravity energy storage, pre-constructing an active control model of the gravity energy storage unit and an inner and outer loop control model of the electrochemical energy storage unit; obtaining the power demand on the grid side; determining the initial values ​​of the parameters of each weight block in the gravity energy storage unit based on the power allocation strategy of the operation control of multiple units; giving the initial output power of the gravity energy storage unit based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and determining the initial output power of the electrochemical energy storage unit; combining the inner and outer loop control models, updating and determining the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit, optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and realizing the operation control of multiple units connected to the grid. The present invention performs coordinated control on a multi-unit power system connected to gravity energy storage, and realizes that the hybrid energy storage system quickly meets the peak and frequency regulation requirements of the grid.

Description

Technical Field

[0001] The present invention belongs to the technical field of new energy power systems, and specifically relates to a method and device for optimizing the operation control of multiple units connected to gravity energy storage. Background Art

[0002] With the development of technology, the cost of renewable energy generation is gradually decreasing, and its proportion in the energy structure is gradually increasing. The output of renewable energy power systems is uncertain and volatile, making forecasting and scheduling more challenging than traditional energy.

[0003] The large-scale application of energy storage systems can improve the flexibility, economy and safety of the grid system connected to renewable energy. Common energy storage methods include: mechanical energy storage, electrochemical energy storage, chemical energy storage, compressed air energy storage, etc. Appropriate energy storage technology can be selected for grid access according to the specific needs and conditions of the grid.

[0004] For example, patent CN105743124A provides a method and system for configuring energy storage for renewable energy power generation. In the scenario of renewable energy access, the proportion of power generation of each type of renewable power source in the power consumption of the entire power grid is obtained. Based on the proportion of power generation of each type of renewable power source, each type of renewable power source is analyzed in sequence according to a preset order to determine whether it needs to be configured with energy storage. The fluctuation amplitude of the net load timing curve is compared with the magnitude relationship of the frequency regulation capability of all online conventional units. Based on the comparison results, the conditions for configuring energy storage to participate in the frequency regulation of the power grid are determined, and the energy storage demand capacity that needs to be configured for renewable energy is determined based on the conditions. Therefore, this solution realizes the energy storage configuration for renewable energy power generation, provides a guiding basis for the configuration plan of energy storage in power grid frequency control, and provides effective support for the country to formulate energy storage-related plans and development policies.

[0005] However, various types of energy storage methods have various restrictions and limitations in practical applications due to their own structures and working principles. For example, gravity energy storage, which is commonly used in mechanical energy storage, has a step-type output power characteristic due to its own mechanical structure limitations.

[0006] For example, patent CN116316581A provides an off-grid photovoltaic-wind energy combined with gravity energy storage system, including the following: using two different types of energy storage technologies, gravity energy storage and battery system, considering technical and economic performance indicators, and providing an evaluation index system for hybrid renewable gravity energy storage system and hybrid renewable battery energy storage; based on the evaluation system, evaluating and analyzing to determine the impact of solar energy, wind energy, and the ratio of solar energy to wind energy on grid cost, storage capacity and oversupply; performing sensitivity analysis on the planning model objective function to obtain the variables that have the greatest impact on the model objective function, and establishing a planning model with reliability constraints, with minimizing system energy consumption as the objective function; providing a new energy management strategy for an off-grid photovoltaic-wind-gravity hybrid energy storage system, and combining the Fmincon interior point method to solve the optimal capacity combination with the lowest system energy cost, the output of the model includes the number of photovoltaic modules and wind turbines, as well as the GES and battery capacity, and determines the optimal operation mode of the hybrid system.

[0007] Taking the existing vertical matrix gravity energy storage system as an example, the potential energy generated by lifting and lowering heavy objects is converted into electrical energy, but the power increase per unit weight block of the gravity system is large, and it is easy to fall in the middle of the power demand on the grid side. That is, if the power demand on the grid side is not an integer multiple of the minimum output power of the gravity energy storage device, it is difficult to achieve the power demand on the grid side by relying solely on the gravity energy storage device, and there is a power shortage.

[0008] Therefore, how to coordinately control a multi-unit power system connected to gravity energy storage so that the hybrid energy storage system can quickly meet the peak and frequency regulation needs of the power grid is an urgent problem to be solved by technical personnel in this field. Summary of the invention

[0009] In view of the defects existing in the above-mentioned prior art, the present invention provides a method and device for optimizing the operation control of multiple units connected to gravity energy storage, pre-constructing the active control model of the gravity energy storage unit and the internal and external loop control models of the electrochemical energy storage unit; obtaining the power demand on the grid side; determining the initial values ​​of the parameters of each weight block in the gravity energy storage unit based on the power allocation strategy of the operation control of multiple units; giving the initial output power of the gravity energy storage unit based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and determining the initial output power of the electrochemical energy storage unit; combining the internal and external loop control models, updating and determining the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit, optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and realizing the operation control of multiple units connected to the grid. The present invention performs coordinated control on the power system of multiple units connected to gravity energy storage, and realizes that the hybrid energy storage system can quickly meet the peak and frequency regulation needs of the grid.

[0010] In a first aspect, the present invention provides a method for optimizing the operation control of multiple units connected to a gravity energy storage system, wherein the multiple units include gravity energy storage units and electrochemical energy storage units respectively connected to a power grid, and the method for optimizing the operation control of multiple units specifically includes the following steps:

[0011] Pre-build the active control model of the gravity energy storage unit and the internal and external loop control models of the electrochemical energy storage unit;

[0012] Obtain power demand on the grid side;

[0013] Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined;

[0014] Based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined;

[0015] By combining the inner and outer loop control models, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, and the operation control of multiple units connected to the power grid is realized.

[0016] Furthermore, the gravity energy storage unit includes a plurality of weight blocks and a synchronous machine, and an active power control model of the gravity energy storage unit is pre-built, which specifically includes the following steps:

[0017] Based on the arrangement relationship of each weight block in the gravity energy storage unit, the relationship between the input mechanical torque of the synchronous machine is established;

[0018] According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed.

[0019] Furthermore, the relationship between the input mechanical torque of the synchronous machine is constructed, which is specifically expressed as:

[0020]

[0021] Among them, T m is the input mechanical torque of the synchronous machine, i is the number of the weight block, n is the total number of weight blocks, is the efficiency of converting the potential energy of the i-weight block into electrical energy, m i is the mass of the i-th weight, v i is the velocity of the i-th weight, g is the acceleration due to gravity, S n is the rated capacity of the gravity energy storage unit;

[0022] Furthermore, according to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed, which is specifically expressed as follows:

[0023]

[0024] in, is the electrical angular velocity of the synchronous machine, is the inertia time constant of the synchronous machine, T m is the input mechanical torque of the synchronous machine, T e is the electromagnetic torque of the synchronous machine, D is the damping coefficient of the gravity energy storage unit, is the power angle of the synchronous machine, is the synchronous speed of the synchronous machine.

[0025] Furthermore, the electrochemical energy storage unit includes a converter, and an inner and outer loop control model of the electrochemical energy storage unit is pre-built, specifically including:

[0026] The inner loop control model of the electrochemical energy storage unit performs decoupling control of the converter d-axis component and the converter q-axis component through feedforward control.

[0027] The outer loop control model of the electrochemical energy storage unit controls the active power output by the electrochemical energy storage unit with the actual value of the current of the converter d axis.

[0028] Furthermore, the inner loop control model of the electrochemical energy storage unit is specifically expressed as:

[0029] ;

[0030] in, is the d-axis component of the modulation voltage output by the converter, is the q-axis component of the regulation voltage output by the converter, is the d-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the q-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the grid side voltage angular velocity, is the filter inductance of the converter, is the actual value of the current in the q axis of the converter, is the actual value of the current on the d-axis of the converter, is the proportional gain of the d-axis during the converter inner loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the d-axis during the converter inner loop control, is the integral gain of the q-axis during the inner loop control of the converter, s is the Laplace operator, is the current reference value of the converter d axis, is the current reference value of the converter q axis;

[0031] The outer loop control model of the electrochemical energy storage unit is specifically expressed as:

[0032] ;

[0033] in, is the proportional gain of the converter outer loop control, is the integral gain of the converter outer loop control, is the reference value of active power output by electrochemical energy storage, It is the active power output by electrochemical energy storage.

[0034] Furthermore, the outer loop control model of the electrochemical energy storage unit also includes:

[0035]

[0036] in, is the proportional gain of the converter outer loop reactive power control, is the integral gain of the converter outer loop reactive power control, is the reactive power reference value output by electrochemical energy storage, It is the reactive power output by electrochemical energy storage.

[0037] Furthermore, the power allocation strategy for multi-unit operation control is specifically expressed as:

[0038] Taking the output power of the gravity energy storage unit as a benchmark and combining the time attributes of the gravity energy storage unit, the gap between the power demand on the grid side and the output power of the gravity energy storage unit is analyzed to determine the output power of the electrochemical energy storage unit.

[0039] Furthermore, each weight block parameter item includes the number of weight blocks put into operation and the time period for which each weight block is put into operation.

[0040] Furthermore, based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined, which is specifically expressed as:

[0041]

[0042] Among them, N gra is the number of weight blocks put into operation in the gravity energy storage unit, mod is the rounding function, P grid_ref is the power demand on the grid side, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, i is the number of the weight block put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation.

[0043] Furthermore, based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0044] Based on the number of weight blocks put into operation in the gravity energy storage unit and the time period in which each weight block is put into operation, the initial output power of the gravity energy storage unit is given, which is specifically expressed as:

[0045] ;

[0046] Among them, P gra_ref is the initial output power of the gravity energy storage unit, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, N gra is the number of weight blocks put into operation in the gravity energy storage unit, i is the number of the weight blocks put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation;

[0047] Based on the power allocation strategy of multi-unit operation control and the initial output power of the gravity energy storage unit, the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0048]

[0049] Among them, P Bess_ref is the initial output power of the electrochemical energy storage unit, P grid_ref is the power demand on the grid side.

[0050] Furthermore, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined by combining the inner and outer loop control models, and the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, including:

[0051] Based on the initial output power of the electrochemical energy storage unit, the initial active power output of the electrochemical energy storage in the outer loop control model is determined, and the initial setting values ​​of each converter parameter in the inner and outer loop control models are given;

[0052] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted to determine the active power output of the electrochemical energy storage in the outer loop control model, update the initial output power of the electrochemical energy storage unit, and determine the output power of the electrochemical energy storage unit;

[0053] Determine the output power of the gravity energy storage unit, and optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, wherein optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit includes optimizing the time period when each weight block in the gravity energy storage unit is put into operation.

[0054] Furthermore, the initial setting value is adjusted with minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, including:

[0055] In order to minimize the maximum frequency difference of the converter connected to the grid, an optimization objective function is constructed. The optimization objective function is specifically expressed as:

[0056]

[0057] Among them, J is the optimization objective function, min is the minimization function, and max is t is the maximum value function at time t, is the frequency deviation at time t;

[0058] Construct the transfer function of the inner loop control and the transfer function of the outer loop control, which can be expressed as follows:

[0059]

[0060] in, is the transfer function of the inner loop control, is the transfer function of the outer loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the q-axis during the converter inner loop control, is the proportional gain of the converter outer loop active control, is the integral gain of the converter outer loop active control, s is the Laplace operator;

[0061] The initial setting value is adjusted by adjusting the outer loop transfer function and the inner loop control function in turn and combining the optimization objective function.

[0062] In a second aspect, the present invention further provides a multi-unit operation control optimization device with gravity energy storage access, which adopts the multi-unit operation control optimization method with gravity energy storage access as described above, specifically comprising:

[0063] The acquisition unit is used to obtain the power demand on the grid side, the active power control model of the pre-built gravity energy storage unit, and the internal and external loop control models of the electrochemical energy storage unit;

[0064] The output power analysis unit is used to determine the initial values ​​of the parameters of each weight block in the gravity energy storage unit based on the power allocation strategy of the multi-unit operation control; based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined;

[0065] The operation control optimization unit is used to combine the inner and outer loop control models, update and determine the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit, optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and realize the operation control of multiple units connected to the power grid.

[0066] Furthermore, the gravity energy storage unit includes a plurality of weight blocks and a synchronous machine, and an active power control model of the gravity energy storage unit is pre-built, which specifically includes the following steps:

[0067] Based on the arrangement relationship of each weight block in the gravity energy storage unit, the relationship between the input mechanical torque of the synchronous machine is established;

[0068] According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed.

[0069] Furthermore, the relationship between the input mechanical torque of the synchronous machine is constructed, which is specifically expressed as:

[0070]

[0071] Among them, T m is the input mechanical torque of the synchronous machine, i is the number of the weight block, n is the total number of weight blocks, is the efficiency of converting the potential energy of the i-weight block into electrical energy, m i is the mass of the i-th weight, v i is the velocity of the i-th weight, g is the acceleration due to gravity, S n is the rated capacity of the gravity energy storage unit;

[0072] Furthermore, according to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed, which is specifically expressed as follows:

[0073]

[0074] in, is the electrical angular velocity of the synchronous machine, is the inertia time constant of the synchronous machine, T mis the input mechanical torque of the synchronous machine, T e is the electromagnetic torque of the synchronous machine, D is the damping coefficient of the gravity energy storage unit, is the power angle of the synchronous machine, is the synchronous speed of the synchronous machine.

[0075] Furthermore, the electrochemical energy storage unit includes a converter, and an inner and outer loop control model of the electrochemical energy storage unit is pre-built, specifically including:

[0076] The inner loop control model of the electrochemical energy storage unit performs decoupling control of the converter d-axis component and the converter q-axis component through feedforward control.

[0077] The outer loop control model of the electrochemical energy storage unit controls the active power output by the electrochemical energy storage unit with the actual value of the current of the converter d axis.

[0078] Furthermore, the inner loop control model of the electrochemical energy storage unit is specifically expressed as:

[0079] ;

[0080] in, is the d-axis component of the modulation voltage output by the converter, is the q-axis component of the regulation voltage output by the converter, is the d-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the q-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the grid side voltage angular velocity, is the filter inductance of the converter, is the actual value of the current in the q axis of the converter, is the actual value of the current on the d-axis of the converter, is the proportional gain of the d-axis during the converter inner loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the d-axis during the converter inner loop control, is the integral gain of the q-axis during the inner loop control of the converter, s is the Laplace operator, is the current reference value of the converter d axis, is the current reference value of the converter q axis;

[0081] The outer loop control model of the electrochemical energy storage unit is specifically expressed as:

[0082] ;

[0083] in, is the proportional gain of the converter outer loop control, is the integral gain of the converter outer loop control, is the reference value of active power output by electrochemical energy storage, It is the active power output by electrochemical energy storage.

[0084] Furthermore, the outer loop control model of the electrochemical energy storage unit also includes:

[0085]

[0086] in, is the proportional gain of the converter outer loop reactive power control, is the integral gain of the converter outer loop reactive power control, is the reactive power reference value output by electrochemical energy storage, It is the reactive power output by electrochemical energy storage.

[0087] Furthermore, the power allocation strategy for multi-unit operation control is specifically expressed as:

[0088] Taking the output power of the gravity energy storage unit as a benchmark and combining the time attributes of the gravity energy storage unit, the gap between the power demand on the grid side and the output power of the gravity energy storage unit is analyzed to determine the output power of the electrochemical energy storage unit.

[0089] Furthermore, each weight block parameter item includes the number of weight blocks put into operation and the time period for which each weight block is put into operation.

[0090] Furthermore, based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined, which is specifically expressed as:

[0091]

[0092] Among them, N gra is the number of weight blocks put into operation in the gravity energy storage unit, mod is the rounding function, P grid_ref is the power demand on the grid side, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, i is the number of the weight block put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation.

[0093] Furthermore, based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0094] Based on the number of weight blocks put into operation in the gravity energy storage unit and the time period in which each weight block is put into operation, the initial output power of the gravity energy storage unit is given, which is specifically expressed as:

[0095] ;

[0096] Among them, P gra_ref is the initial output power of the gravity energy storage unit, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, N gra is the number of weight blocks put into operation in the gravity energy storage unit, i is the number of the weight blocks put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation;

[0097] Based on the power allocation strategy of multi-unit operation control and the initial output power of the gravity energy storage unit, the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0098]

[0099] Among them, P Bess_ref is the initial output power of the electrochemical energy storage unit, P grid_ref is the power demand on the grid side.

[0100] Furthermore, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined by combining the inner and outer loop control models, and the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, including:

[0101] Based on the initial output power of the electrochemical energy storage unit, the initial active power output of the electrochemical energy storage in the outer loop control model is determined, and the initial setting values ​​of each converter parameter in the inner and outer loop control models are given;

[0102] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted to determine the active power output of the electrochemical energy storage in the outer loop control model, update the initial output power of the electrochemical energy storage unit, and determine the output power of the electrochemical energy storage unit;

[0103] Determine the output power of the gravity energy storage unit, and optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, wherein optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit includes optimizing the time period when each weight block in the gravity energy storage unit is put into operation.

[0104] Furthermore, the initial setting value is adjusted with minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, including:

[0105] In order to minimize the maximum frequency difference of the converter connected to the grid, an optimization objective function is constructed. The optimization objective function is specifically expressed as:

[0106]

[0107] Among them, J is the optimization objective function, min is the minimization function, and max is t is the maximum value function at time t, is the frequency deviation at time t;

[0108] Construct the transfer function of the inner loop control and the transfer function of the outer loop control, which can be expressed as follows:

[0109]

[0110] in, is the transfer function of the inner loop control, is the transfer function of the outer loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the q-axis during the converter inner loop control, is the proportional gain of the converter outer loop active control, is the integral gain of the converter outer loop active control, s is the Laplace operator;

[0111] The initial setting value is adjusted by adjusting the outer loop transfer function and the inner loop control function in turn and combining the optimization objective function.

[0112] The invention provides a multi-unit operation control optimization method with gravity energy storage access, which has at least the following beneficial effects:

[0113] (1) For the multi-unit power system connected to gravity energy storage, coordinated control can be carried out. Electrochemical energy storage can supplement the shortfall between the power demand on the grid side and the output power of gravity energy storage, and the optimal time-sequential coordinated control of gravity energy storage and electrochemical energy storage can be set up to enable the hybrid energy storage system to quickly meet the peak and frequency regulation needs of the grid.

[0114] (2) In the multi-generator units connected to gravity energy storage, coordinated control is achieved by combining electrochemical energy storage. During coordinated control, the power of electrochemical energy storage and gravity energy storage is matched, and the overall performance of the entire multi-generator unit is optimized through the rapid response characteristics of electrochemical energy storage and the large-scale energy storage characteristics of gravity energy storage.

[0115] (3) Based on the initial output power of the electrochemical energy storage unit and combined with the internal and external loop control models of the electrochemical energy storage unit, the output power of the electrochemical energy storage unit is updated and determined, the parameters of the electrochemical energy storage unit are optimized, and the charging and discharging power of the energy storage unit is reasonably allocated. In this way, the service life of the electrochemical energy storage unit is extended while better responding to the frequency regulation and peak regulation needs of the power grid and improving the regulation capacity and operation stability of the power grid. BRIEF DESCRIPTION OF THE DRAWINGS

[0116] Figure 1 A schematic diagram of a flow chart of a multi-unit operation control optimization method for gravity energy storage access provided by the present invention;

[0117] Figure 2 A schematic diagram of a flow chart of constructing an active power control model of a gravity energy storage unit according to a certain embodiment of the present invention;

[0118] Figure 3 A schematic diagram of a flow chart of constructing an inner and outer loop control model of an electrochemical energy storage unit according to a certain embodiment of the present invention;

[0119] Figure 4 A schematic diagram of the grid-connected topology structure and the output power of multiple units provided by the present invention;

[0120] Figure 5 A structural schematic diagram of a multi-unit operation control optimization device connected to a gravity energy storage provided by the present invention. DETAILED DESCRIPTION

[0121] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0122] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings, and "multiple" generally includes at least two.

[0123] It should also be noted that the term "includes", "comprising" or any other variation thereof is intended to cover non-exclusive inclusion, so that a commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprising a ..." do not exclude the existence of other identical elements in the commodity or device including the elements.

[0124] From the analysis of the step output characteristics of gravity energy storage, on the one hand, there is a fixed interval time for the input of weight blocks in gravity energy storage, and the gravity energy storage device as a single energy storage technology type is difficult to meet the real-time power demand of the power grid side; on the other hand, due to the structure and working principle of the weight blocks, the entire gravity energy storage device has a minimum output power. If the power demand on the grid side is not an integer multiple of the minimum output power of the gravity energy storage device, it is difficult to achieve the power demand on the grid side by relying solely on the gravity energy storage device, and there is a power shortage.

[0125] By coordinating the control of multiple-unit power systems connected to gravity energy storage, electrochemical energy storage can supplement the shortfall between the power demand on the grid side and the output power of gravity energy storage, and set up optimal time-sequential coordinating control of gravity energy storage and electrochemical energy storage, so that the hybrid energy storage system can quickly meet the peak and frequency regulation needs of the grid.

[0126] like Figure 1 As shown, the present invention provides a method for optimizing the operation control of multiple units connected to gravity energy storage, characterized in that the multiple units include gravity energy storage units and electrochemical energy storage units respectively connected to the power grid, and the method for optimizing the operation control of multiple units specifically includes the following steps:

[0127] Pre-build the active control model of the gravity energy storage unit and the internal and external loop control models of the electrochemical energy storage unit;

[0128] Obtain power demand on the grid side;

[0129] Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined;

[0130] Based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined;

[0131] By combining the inner and outer loop control models, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, and the operation control of multiple units connected to the power grid is realized.

[0132] The present invention performs coordinated control on a multi-unit power system connected to gravity energy storage, uses electrochemical energy storage to supplement the shortfall between the power demand on the grid side and the output power of the gravity energy storage, and sets up optimal time-sequential coordinated control of gravity energy storage and electrochemical energy storage, so as to enable the hybrid energy storage system to quickly meet the peak and frequency regulation needs of the grid.

[0133] like Figure 2 As shown, the gravity energy storage unit includes a plurality of weight blocks and a synchronous machine, and an active control model of the gravity energy storage unit is pre-built, which specifically includes the following steps:

[0134] Based on the arrangement relationship of each weight block in the gravity energy storage unit, the relationship between the input mechanical torque of the synchronous machine is established;

[0135] According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed.

[0136] The working mode of the gravity energy storage unit is to realize electromechanical energy conversion by driving the connected synchronous machine through discretely distributed weight blocks, and the synchronous machine is connected to the power grid. The active power control of the gravity energy storage unit needs to consider both the control unit and the regulation unit to adapt to the power demand and frequency regulation on the grid side.

[0137] For example, the mechanical torque that directly affects the charging and discharging speed and power output of the gravity energy storage unit is one of the key factors. The value of the mechanical torque determines the lifting or lowering of the control weight block. The mechanical torque is related to the weight block parameter item. Therefore, for the active control model of the gravity energy storage unit, it is necessary to first construct the relationship between each weight block parameter item and the input mechanical torque of the synchronous machine. Among them, the weight block parameter items include the number of weight blocks put into operation, the time period for each weight block to be put into operation, the mass of each weight block, the speed of each weight block when the potential energy is converted into kinetic energy, etc.

[0138] The relationship between the input mechanical torque of the synchronous machine is expressed as:

[0139]

[0140] Among them, T m is the input mechanical torque of the synchronous machine, i is the number of the weight block, n is the total number of weight blocks, is the efficiency of converting the potential energy of the i-weight block into electrical energy, m i is the mass of the i-th weight, v i is the velocity of the i-th weight, g is the acceleration due to gravity, S n is the rated capacity of the gravity energy storage unit.

[0141] In order to ensure that the gravity energy storage unit operates synchronously with the grid side and the frequency and phase are synchronized, it is also necessary to construct an active control model of the gravity energy storage unit based on the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine. The specific expression is:

[0142] ;

[0143] in, is the electrical angular velocity of the synchronous machine, is the inertia time constant of the synchronous machine, T m is the input mechanical torque of the synchronous machine, T e is the electromagnetic torque of the synchronous machine, D is the damping coefficient of the gravity energy storage unit, is the power angle of the synchronous machine, is the synchronous speed of the synchronous machine.

[0144] Among them, the electrical parameter items of the synchronous machine include the electrical angular velocity of the synchronous machine, the inertia time constant of the synchronous machine, the electromagnetic torque of the synchronous machine, the power angle of the synchronous machine, the synchronous speed of the synchronous machine, etc.

[0145] Comprehensive consideration of parameters such as mechanical torque, electrical parameters of synchronous machines and characteristics of gravity energy storage units can ensure that the gravity energy storage unit effectively responds to grid-side demand while also ensuring synchronous operation with the grid side.

[0146] The electrochemical energy storage unit includes an inverter, and the inner and outer loop control models of the electrochemical energy storage unit can be constructed from the perspective of grid-following control of electrochemical energy storage. The inverter is usually based on a dual closed-loop control strategy, including an inner loop and an outer loop. The inner loop can also be called a current loop, and the outer loop can be called a power loop. The outer loop generates d-axis and q-axis current commands based on active power and reactive power commands; the inner loop is responsible for tracking current commands and controlling the current of the flowing electrochemical energy storage device by adjusting the output voltage of the inverter.

[0147] Therefore, the inner and outer loop control models of the electrochemical energy storage unit can be specifically divided into the inner loop control model of the electrochemical energy storage unit and the outer loop control model of the electrochemical energy storage unit.

[0148] like Figure 3 As shown, the internal and external loop control models of the electrochemical energy storage unit are pre-built, specifically including:

[0149] The inner loop control model of the electrochemical energy storage unit performs decoupling control of the converter d-axis component and the converter q-axis component through feedforward control.

[0150] The outer loop control model of the electrochemical energy storage unit controls the active power output by the electrochemical energy storage unit with the actual value of the current of the converter d axis.

[0151] The inner loop control model of the electrochemical energy storage unit is specifically expressed as:

[0152] ;

[0153] in, is the d-axis component of the modulation voltage output by the converter, is the q-axis component of the regulation voltage output by the converter, is the d-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the q-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the grid side voltage angular velocity, is the filter inductance of the converter, is the actual value of the current in the q axis of the converter, is the actual value of the current on the d-axis of the converter, is the proportional gain of the d-axis during the converter inner loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the d-axis during the converter inner loop control, is the integral gain of the q-axis during the inner loop control of the converter, s is the Laplace operator, is the current reference value of the converter d axis, is the current reference value of the converter q axis;

[0154] The outer loop control model of the electrochemical energy storage unit is specifically expressed as:

[0155] ;

[0156] in, is the proportional gain of the converter outer loop control, is the integral gain of the converter outer loop control, is the reference value of active power output by electrochemical energy storage, It is the active power output by electrochemical energy storage.

[0157] The outer loop control model of the electrochemical energy storage unit also includes:

[0158]

[0159] in, is the proportional gain of the converter outer loop reactive power control, is the integral gain of the converter outer loop reactive power control, is the reactive power reference value output by electrochemical energy storage, It is the reactive power output by electrochemical energy storage.

[0160] In the multi-units connected to gravity energy storage, coordinated control is achieved by combining electrochemical energy storage. During coordinated control, it is necessary to achieve power matching between electrochemical energy storage and gravity energy storage, and optimize the overall performance of the entire multi-unit through the rapid response characteristics of electrochemical energy storage and the large-scale energy storage characteristics of gravity energy storage.

[0161] The power allocation strategy for multi-unit operation control is mainly to use electrochemical energy storage to supplement the shortfall between the power demand on the grid side and the output power of gravity energy storage, which is specifically expressed as:

[0162] Taking the output power of the gravity energy storage unit as a benchmark and combining the time attributes of the gravity energy storage unit, the gap between the power demand on the grid side and the output power of the gravity energy storage unit is analyzed to determine the output power of the electrochemical energy storage unit.

[0163] The parameter items of each weight block include the number of weight blocks put into operation and the time period for which each weight block is put into operation.

[0164] Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined, which can be specifically expressed as:

[0165]

[0166] Among them, N gra is the number of weight blocks put into operation in the gravity energy storage unit, mod is the rounding function, P grid_ref is the power demand on the grid side, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, i is the number of the weight block put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation.

[0167] Based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0168] Based on the number of weight blocks put into operation in the gravity energy storage unit and the time period in which each weight block is put into operation, the initial output power of the gravity energy storage unit is given, which is specifically expressed as:

[0169] ;

[0170] Among them, P gra_ref is the initial output power of the gravity energy storage unit, P gra_singleis the power change corresponding to a single weight block in the gravity energy storage unit, N gra is the number of weight blocks put into operation in the gravity energy storage unit, i is the number of the weight blocks put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation;

[0171] Based on the power allocation strategy of multi-unit operation control and the initial output power of the gravity energy storage unit, the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0172]

[0173] Among them, P Bess_ref is the initial output power of the electrochemical energy storage unit, P grid_ref is the power demand on the grid side.

[0174] The power allocation strategy controlled by multiple units is mainly based on the step output power characteristics of gravity energy storage. During the interval of the weight block input of the gravity energy storage unit, the output power of the gravity energy storage unit is used as the benchmark, and the rapid power response characteristics of electrochemical energy storage are integrated to quickly respond to the power changes on the grid side and make up for the difference between the grid demand and the output power of the gravity energy storage unit. The power allocation strategy controlled by multiple units allows the gravity energy storage unit and the electrochemical energy storage unit to work together to meet the power demand for peak and frequency regulation on the grid side.

[0175] Combined with the inner and outer loop control models, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined, and the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, including:

[0176] Based on the initial output power of the electrochemical energy storage unit, the initial active power output of the electrochemical energy storage in the outer loop control model is determined, and the initial setting values ​​of each converter parameter in the inner and outer loop control models are given;

[0177] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted to determine the active power output of the electrochemical energy storage in the outer loop control model, update the initial output power of the electrochemical energy storage unit, and determine the output power of the electrochemical energy storage unit;

[0178] Determine the output power of the gravity energy storage unit, and optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, wherein optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit includes optimizing the time period when each weight block in the gravity energy storage unit is put into operation.

[0179] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted, including:

[0180] In order to minimize the maximum frequency difference of the converter connected to the grid, an optimization objective function is constructed. The optimization objective function is specifically expressed as:

[0181]

[0182] Among them, J is the optimization objective function, min is the minimization function, and max is t is the maximum value function at time t, is the frequency deviation at time t;

[0183] Construct the transfer function of the inner loop control and the transfer function of the outer loop control, which can be expressed as follows:

[0184]

[0185] in, is the transfer function of the inner loop control, is the transfer function of the outer loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the q-axis during the converter inner loop control, is the proportional gain of the converter outer loop active control, is the integral gain of the converter outer loop active control, s is the Laplace operator;

[0186] The initial setting value is adjusted by adjusting the outer loop transfer function and the inner loop control function in turn and combining the optimization objective function.

[0187] Based on the initial output power of the electrochemical energy storage unit and combined with the internal and external loop control models of the electrochemical energy storage unit, the output power of the electrochemical energy storage unit is updated and determined, the parameters of the electrochemical energy storage unit are optimized, and the charging and discharging power of the energy storage unit is reasonably allocated. In this way, the service life of the electrochemical energy storage unit is extended while better responding to the frequency and peak regulation needs of the power grid and improving the regulation capacity and operation stability of the power grid.

[0188] In one embodiment, there is a multi-unit energy storage system including gravity energy storage, wherein the gravity energy storage is directly connected to the grid through the synchronous machine, and the electrochemical energy storage is connected to the grid through the converter. The schematic diagram of the grid-connected topology is as follows: Figure 4 The gravity energy storage mechanical device in the gravity energy storage unit is equipped with a plurality of weight blocks, the mass of each weight block can be the same or different, and the maximum operating speed during the ascent / descent can be the same or different.

[0189] The synchronous machine in the gravity energy storage unit is a permanent magnet synchronous generator. The synchronous generator has a maximum output power, which can be selected according to the model of the synchronous generator, such as 10MW or other power sizes. Electrochemical energy storage adopts a grid-following control strategy, and the capacity can be determined according to the application scenario and selection, such as 7MW or other sizes.

[0190] in accordance with Figure 4 The grid-connected topology shown in the figure is used to simulate the grid-connected operation of a multi-unit energy storage system with gravity energy storage. At a certain moment in the simulation, the power demand instruction on the grid side changes from 0MW to XXMW. Based on the power demand instruction on the grid side, the power demand on the grid side is realized by gravity energy storage first. In the time interval when XXX weight blocks are put into the gravity energy storage, the power distribution strategy between gravity energy storage and electrochemical energy storage is used to distribute the timing power instructions to the gravity energy storage and electrochemical energy storage, and the initial output power of the "gravity-electrochemical" hybrid energy storage system, the initial output power of the gravity energy storage unit and the initial output power of the electrochemical energy storage are obtained respectively.

[0191] Similarly, if Figure 4 As shown in the figure, from the perspective of time, the gravity energy storage unit puts in the first weight block at XXXX s, and after each N s, puts in the corresponding second, third, and Mth weight blocks. During the time period when the weight blocks of the gravity energy storage unit are sequentially put into operation, the difference between the power demand on the grid side and the actual power generated by the gravity energy storage is realized by the electrochemical energy storage, and as the weight blocks are put in one by one, the output power of the gravity energy storage increases in a step-by-step manner, and the electrochemical energy storage gradually decreases. In this way, the characteristic of the constant output power of the multi-unit hybrid energy storage containing gravity energy storage is realized, thereby tracking the power demand on the grid side.

[0192] Get Figure 4 After the initial output power curve of the electrochemical energy storage shown in the figure, combined with the transfer function of the inner loop control and the transfer function of the outer loop control, the initial output power curve of the electrochemical energy storage is updated and adjusted based on minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal. At the same time, based on the power allocation strategy of multi-unit operation control that realizes the difference between the power demand on the grid side and the actual power generated by the gravity energy storage, the initial output power of the gravity energy storage is adjusted (mainly for the time period when each heavy block is put into operation). Finally, the operation control of the multiple units connected to the grid is realized.

[0193] like Figure 5 As shown, the present invention also provides a multi-unit operation control optimization device connected to gravity energy storage, which adopts the multi-unit operation control optimization method connected to gravity energy storage as mentioned above, specifically comprising:

[0194] The acquisition unit is used to obtain the power demand on the grid side, the active power control model of the pre-built gravity energy storage unit, and the internal and external loop control models of the electrochemical energy storage unit;

[0195] The output power analysis unit is used to determine the initial values ​​of the parameters of each weight block in the gravity energy storage unit based on the power allocation strategy of the multi-unit operation control; based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined;

[0196] The operation control optimization unit is used to combine the inner and outer loop control models, update and determine the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit, optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and realize the operation control of multiple units connected to the power grid.

[0197] The gravity energy storage unit includes a plurality of weight blocks and a synchronous machine. The active control model of the gravity energy storage unit is pre-built, which specifically includes the following steps:

[0198] Based on the arrangement relationship of each weight block in the gravity energy storage unit, the relationship between the input mechanical torque of the synchronous machine is established;

[0199] According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed.

[0200] The relationship between the input mechanical torque of the synchronous machine is expressed as:

[0201]

[0202] Among them, T m is the input mechanical torque of the synchronous machine, i is the number of the weight block, n is the total number of weight blocks, is the efficiency of converting the potential energy of the i-weight block into electrical energy, m i is the mass of the i-th weight, v i is the velocity of the i-th weight, g is the acceleration due to gravity, S n is the rated capacity of the gravity energy storage unit;

[0203] According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed, which is specifically expressed as follows:

[0204] ;

[0205] in, is the electrical angular velocity of the synchronous machine, is the inertia time constant of the synchronous machine, T m is the input mechanical torque of the synchronous machine, Te is the electromagnetic torque of the synchronous machine, D is the damping coefficient of the gravity energy storage unit, is the power angle of the synchronous machine, is the synchronous speed of the synchronous machine.

[0206] The electrochemical energy storage unit includes a converter, and an internal and external loop control model of the electrochemical energy storage unit is pre-built, specifically including:

[0207] The inner loop control model of the electrochemical energy storage unit performs decoupling control of the converter d-axis component and the converter q-axis component through feedforward control.

[0208] The outer loop control model of the electrochemical energy storage unit controls the active power output by the electrochemical energy storage unit with the actual value of the current of the converter d axis.

[0209] The inner loop control model of the electrochemical energy storage unit is specifically expressed as:

[0210] ;

[0211] in, is the d-axis component of the modulation voltage output by the converter, is the q-axis component of the regulation voltage output by the converter, is the d-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the q-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the grid side voltage angular velocity, is the filter inductance of the converter, is the actual value of the current in the q axis of the converter, is the actual value of the current on the d-axis of the converter, is the proportional gain of the d-axis during the converter inner loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the d-axis during the converter inner loop control, is the integral gain of the q-axis during the inner loop control of the converter, s is the Laplace operator, is the current reference value of the converter d axis, is the current reference value of the converter q axis;

[0212] The outer loop control model of the electrochemical energy storage unit is specifically expressed as:

[0213] ;

[0214] in, is the proportional gain of the converter outer loop control, is the integral gain of the converter outer loop control, is the reference value of active power output by electrochemical energy storage, It is the active power output by electrochemical energy storage.

[0215] The outer loop control model of the electrochemical energy storage unit also includes:

[0216]

[0217] in, is the proportional gain of the converter outer loop reactive power control, is the integral gain of the converter outer loop reactive power control, is the reactive power reference value output by electrochemical energy storage, It is the reactive power output by electrochemical energy storage.

[0218] The power allocation strategy for multi-unit operation control is specifically expressed as:

[0219] Taking the output power of the gravity energy storage unit as a benchmark and combining the time attributes of the gravity energy storage unit, the gap between the power demand on the grid side and the output power of the gravity energy storage unit is analyzed to determine the output power of the electrochemical energy storage unit.

[0220] The parameter items of each weight block include the number of weight blocks put into operation and the time period for which each weight block is put into operation.

[0221] Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined, which can be specifically expressed as:

[0222]

[0223] Among them, N gra is the number of weight blocks put into operation in the gravity energy storage unit, mod is the rounding function, P grid_ref is the power demand on the grid side, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, i is the number of the weight block put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation.

[0224] Based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0225] Based on the number of weight blocks put into operation in the gravity energy storage unit and the time period in which each weight block is put into operation, the initial output power of the gravity energy storage unit is given, which is specifically expressed as:

[0226] ;

[0227] Among them, P gra_ref is the initial output power of the gravity energy storage unit, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, N gra is the number of weight blocks put into operation in the gravity energy storage unit, i is the number of the weight blocks put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation;

[0228] Based on the power allocation strategy of multi-unit operation control and the initial output power of the gravity energy storage unit, the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as:

[0229]

[0230] Among them, P Bess_ref is the initial output power of the electrochemical energy storage unit, P grid_ref is the power demand on the grid side.

[0231] Combined with the inner and outer loop control models, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined, and the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, including:

[0232] Based on the initial output power of the electrochemical energy storage unit, the initial active power output of the electrochemical energy storage in the outer loop control model is determined, and the initial setting values ​​of each converter parameter in the inner and outer loop control models are given;

[0233] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted to determine the active power output of the electrochemical energy storage in the outer loop control model, update the initial output power of the electrochemical energy storage unit, and determine the output power of the electrochemical energy storage unit;

[0234] Determine the output power of the gravity energy storage unit, and optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, wherein optimizing the initial values ​​of the parameters of each weight block in the gravity energy storage unit includes optimizing the time period when each weight block in the gravity energy storage unit is put into operation.

[0235] Taking minimizing the maximum frequency difference of the converter connected to the grid as the optimization goal, the initial setting value is adjusted, including:

[0236] In order to minimize the maximum frequency difference of the converter connected to the grid, an optimization objective function is constructed. The optimization objective function is specifically expressed as:

[0237]

[0238] Among them, J is the optimization objective function, min is the minimization function, and max is t is the maximum value function at time t, is the frequency deviation at time t;

[0239] Construct the transfer function of the inner loop control and the transfer function of the outer loop control, which can be expressed as follows:

[0240]

[0241] in, is the transfer function of the inner loop control, is the transfer function of the outer loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the q-axis during the converter inner loop control, is the proportional gain of the converter outer loop active control, is the integral gain of the converter outer loop active control, s is the Laplace operator;

[0242] The initial setting value is adjusted by adjusting the outer loop transfer function and the inner loop control function in turn and combining the optimization objective function.

[0243] The invention provides a multi-unit operation control optimization method with gravity energy storage access, which has at least the following beneficial effects:

[0244] (1) For the multi-unit power system connected to gravity energy storage, coordinated control can be carried out. Electrochemical energy storage can supplement the shortfall between the power demand on the grid side and the output power of gravity energy storage, and the optimal time-sequential coordinated control of gravity energy storage and electrochemical energy storage can be set up to enable the hybrid energy storage system to quickly meet the peak and frequency regulation needs of the grid.

[0245] (2) In the multi-generator units connected to gravity energy storage, coordinated control is achieved by combining electrochemical energy storage. During coordinated control, the power of electrochemical energy storage and gravity energy storage is matched, and the overall performance of the entire multi-generator unit is optimized through the rapid response characteristics of electrochemical energy storage and the large-scale energy storage characteristics of gravity energy storage.

[0246] (3) Based on the initial output power of the electrochemical energy storage unit and combined with the internal and external loop control models of the electrochemical energy storage unit, the output power of the electrochemical energy storage unit is updated and determined, the parameters of the electrochemical energy storage unit are optimized, and the charging and discharging power of the energy storage unit is reasonably allocated. In this way, the service life of the electrochemical energy storage unit is extended while better responding to the frequency regulation and peak regulation needs of the power grid and improving the regulation capacity and operation stability of the power grid.

[0247] The present invention also provides a computer device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein when the processor executes the computer program, any one of the above-mentioned methods for optimizing the operation control of multiple units connected to gravity energy storage is implemented.

[0248] Specifically, a computer device may include one or more processing devices, such as one or more central processing units (CPUs), each of which may implement one or more hardware threads. A computer device may also include any storage resource for storing any type of information such as code, settings, data, etc. Without limitation, for example, a storage resource may include any one or more combinations of the following: any type of RAM, any type of ROM, a flash memory device, a hard disk, an optical disk, etc. More generally, any storage resource may use any technology to store information.

[0249] Further, any storage resource may provide volatile or non-volatile retention of information. Further, any storage resource may represent a fixed or removable component of a computer device. In one case, when a processing device executes an associated instruction stored in any storage resource or a combination of storage resources, the computer device may perform any operation of the associated instruction. The computer device also includes one or more drive mechanisms for interacting with any storage resource, such as a hard disk drive mechanism, an optical disk drive mechanism, etc.

[0250] The computer device may also include an input / output module (I / O) for receiving various inputs (via input devices) and for providing various outputs (via output devices). A specific output mechanism may include a presentation device and an associated graphical user interface (GUI). In other embodiments, the input / output module (I / O), input devices, and output devices may not be included, and the computer device may be used only as a computer device in a network. The computer device may also include one or more network interfaces for exchanging data with other devices via one or more communication links. One or more communication buses couple the components described above together.

[0251] The communication link may be implemented in any manner, for example, through a local area network, a wide area network (e.g., the Internet), a point-to-point connection, etc., or any combination thereof. The communication link may include any combination of hardwired links, wireless links, routers, gateway functions, name servers, etc., governed by any protocol or combination of protocols.

[0252] The beneficial effects obtained by the above-mentioned equipment and devices are consistent with the beneficial effects obtained by the above-mentioned methods, and are not described in detail in the embodiments of this specification.

[0253] Although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments by those skilled in the art once the basic inventive concepts are known. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A multi-unit operation control optimization method with gravity energy storage access, characterized in that: The multiple units include gravity energy storage units and electrochemical energy storage units respectively connected to the power grid. The multiple unit operation control optimization method specifically includes the following steps: Pre-build the active control model of the gravity energy storage unit and the internal and external loop control models of the electrochemical energy storage unit; Obtain power demand on the grid side; Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined. The power allocation strategy of multi-unit operation control is specifically expressed as follows: taking the output power of the gravity energy storage unit as a benchmark, combined with the time attribute of the gravity energy storage unit, analyzing the shortfall between the power demand on the grid side and the output power of the gravity energy storage unit, and determining the output power of the electrochemical energy storage unit; Based on the initial values ​​of the parameter items of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined, wherein the parameter items of each weight block include the number of weight blocks put into operation and the time period for each weight block to be put into operation; Based on the number of weight blocks put into operation in the gravity energy storage unit and the time period in which each weight block is put into operation, the initial output power of the gravity energy storage unit is given, which is specifically expressed as: ； Among them, P gra_ref is the initial output power of the gravity energy storage unit, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, N gra is the number of weight blocks put into operation in the gravity energy storage unit, i is the number of the weight blocks put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation; Based on the power allocation strategy of multi-unit operation control and the initial output power of the gravity energy storage unit, the initial output power of the electrochemical energy storage unit is determined, which is specifically expressed as: ； Among them, P Bess_ref is the initial output power of the electrochemical energy storage unit, P grid_ref is the power demand on the grid side; By combining the inner and outer loop control models, the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit are updated and determined, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are optimized, and the operation control of multiple units connected to the power grid is realized.

2. The multi-unit operation control optimization method connected to gravity energy storage as claimed in claim 1 is characterized in that: The gravity energy storage unit includes a plurality of weight blocks and a synchronous machine. The active control model of the gravity energy storage unit is pre-built, which specifically includes the following steps: Based on the arrangement relationship of each weight block in the gravity energy storage unit, the relationship between the input mechanical torque of the synchronous machine is established; According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed.

3. The multi-unit operation control optimization method connected to gravity energy storage as claimed in claim 2 is characterized in that: According to the relationship between the input mechanical torque of the synchronous machine and the electrical parameter items of the synchronous machine, the active power control model of the gravity energy storage unit is constructed, which is specifically expressed as follows: ； in, is the electrical angular velocity of the synchronous machine, is the inertia time constant of the synchronous machine, T m is the input mechanical torque of the synchronous machine, T e is the electromagnetic torque of the synchronous machine, D is the damping coefficient of the gravity energy storage unit, is the power angle of the synchronous machine, is the synchronous speed of the synchronous machine.

4. The multi-unit operation control optimization method for gravity energy storage access as claimed in claim 1 is characterized in that: The electrochemical energy storage unit includes a converter, and an internal and external loop control model of the electrochemical energy storage unit is pre-built, specifically including: The inner loop control model of the electrochemical energy storage unit performs decoupling control of the converter d-axis component and the converter q-axis component through feedforward control. The outer loop control model of the electrochemical energy storage unit controls the active power output by the electrochemical energy storage unit with the actual value of the current of the converter d axis.

5. The multi-unit operation control optimization method connected to gravity energy storage as claimed in claim 4 is characterized in that: The inner loop control model of the electrochemical energy storage unit is specifically expressed as: ； in, is the d-axis component of the modulation voltage output by the converter, is the q-axis component of the regulation voltage output by the converter, is the d-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the q-axis voltage at the grid-connected point of the electrochemical energy storage unit, is the grid side voltage angular velocity, is the filter inductance of the converter, is the actual value of the current in the q axis of the converter, is the actual value of the current on the d-axis of the converter, is the proportional gain of the d-axis during the converter inner loop control, is the proportional gain of the q-axis during the converter inner loop control, is the integral gain of the d-axis during the converter inner loop control, is the integral gain of the q-axis during the inner loop control of the converter, s is the Laplace operator, is the current reference value of the converter d axis, is the current reference value of the converter q axis; The outer loop control model of the electrochemical energy storage unit is specifically expressed as: ； in, is the proportional gain of the converter outer loop control, is the integral gain of the converter outer loop control, is the reference value of active power output by electrochemical energy storage, It is the active power output by electrochemical energy storage.

6. The multi-unit operation control optimization method connected to gravity energy storage as claimed in claim 1 is characterized in that: Based on the power allocation strategy of multi-unit operation control, the initial values ​​of the parameters of each weight block in the gravity energy storage unit are determined, which can be specifically expressed as: ； Among them, N gra is the number of weight blocks put into operation in the gravity energy storage unit, mod is the rounding function, P grid_ref is the power demand on the grid side, P gra_single is the power change corresponding to a single weight block in the gravity energy storage unit, i is the number of the weight block put into operation, t on_i is the time period during which the i-th weight block is put into operation, t on_1 is the time period when the first weight block is put into operation, t on_i-1 is the time period when the i-1th weight block is put into operation, and Δt is the interval time when the weight blocks in the gravity energy storage unit are put into operation.

7. A multi-unit operation control optimization device connected to gravity energy storage, characterized in that: The multi-unit operation control optimization method using gravity energy storage access as described in any one of claims 1 to 6 specifically includes: The acquisition unit is used to obtain the power demand on the grid side, the active power control model of the pre-built gravity energy storage unit, and the internal and external loop control models of the electrochemical energy storage unit; The output power analysis unit is used to determine the initial values ​​of the parameters of each weight block in the gravity energy storage unit based on the power allocation strategy of the multi-unit operation control; based on the initial values ​​of the parameters of each weight block in the gravity energy storage unit, the initial output power of the gravity energy storage unit is given, and the initial output power of the electrochemical energy storage unit is determined; The operation control optimization unit is used to combine the inner and outer loop control models, update and determine the output power of the electrochemical energy storage unit and the output power of the gravity energy storage unit, optimize the initial values ​​of the parameters of each weight block in the gravity energy storage unit, and realize the operation control of multiple units connected to the power grid.

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