New energy dual-energy storage system safe and stable operation control equipment and new energy system

Abstract

The invention relates to safe and stable operation control equipment for a new energy double-energy-storage system and a new energy system. The equipment comprises a power processing device and a power superposition device, the power processing device is used for processing power emitted by a new energy power generation system by adopting at least two-order high-pass filtering modules to obtain power needing to be compensated, and the power superposition device is used for superposing the power generated by the new energy power generation system. The real compensation power of the first energy storage group and the second energy storage group in the energy storage system is determined according to the power needing to be compensated; wherein the at least two-order high-pass filtering module is used for filtering a direct current component caused by a phase difference between the grid-connected power of the power grid system and the power emitted by the new energy power generation system; and the power superposition device is used for superposing the power emitted by the new energy power generation system and the actually compensated power to obtain grid-connected power output to the power grid system. By adopting the scheme, the operation stability and safety of the dual-energy storage system can be improved.

Description

Technical Field

[0001] The present application relates to the field of new energy technologies, and particularly to a control device for the safe and stable operation of a new energy dual energy storage system and a new energy system. Background Art

[0002] In recent years, new energy sources such as wind power and photovoltaic power have become the main force of development due to their characteristics of being pollution-free, sustainable, and having mature technologies. However, the output of new energy is randomly volatile, posing challenges to the safe and stable operation of the power system during the grid connection process. An energy storage system is configured at a new energy station, and its fast charge and discharge response characteristics are used to cancel the fluctuating part of the new energy power to reduce its negative impact on grid connection. The cost of the energy storage system is relatively high. Therefore, it is of great significance to extend the operation life of the energy storage system.

[0003] For an energy storage system, the main factors affecting its operation life include the number of charge and discharge cycles, etc. During the process of canceling the fluctuating power of new energy, the energy storage system needs to frequently switch between charge and discharge to track the random fluctuations of new energy power, resulting in an increase in its charge and discharge times and reducing the stability and safety of the operation of the dual energy storage system. Summary of the Invention

[0004] Based on this, the present application provides a control device for the safe and stable operation of a new energy dual energy storage system and a new energy system, which can improve the stability and safety of the operation of the dual energy storage system.

[0005] In a first aspect, the present application provides a control device for the safe and stable operation of a new energy dual energy storage system, and the device includes:

[0006] A power processing device, configured to process the power generated by a new energy power generation system by using at least a two-stage high-pass filter module to obtain the power to be compensated, and determine the actually compensated power of a first energy storage group and a second energy storage group in the energy storage system according to the power to be compensated; wherein, the at least two-stage high-pass filter module is used to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system.

[0007] A power superposition device, configured to superpose the power generated by the new energy power generation system and the actually compensated power to obtain the grid-connected power output to the power grid system.

[0008] In some embodiments, the power processing device includes:

[0009] At least a two-stage high-pass filter module, configured to process the power generated by the new energy power generation system to obtain the power to be compensated;

[0010] A power adjustment module, configured to determine the power output by a first energy storage group and a second energy storage group in an energy storage system according to the power to be compensated, and adjust the power output by the first energy storage group and the second energy storage group to obtain the truly compensated power.

[0011] In some embodiments, the at least two-stage high-pass filter module includes:

[0012] A second-order high-pass filter unit, configured to perform filtering processing on the power generated by a new energy power generation system to obtain the filtered power; wherein, the second-order high-pass filter unit is configured to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system.

[0013] A gain unit, configured to perform gain processing on the filtered power by using a target gain to obtain the power to be compensated; wherein, the target gain is used to adjust the energy storage output power of the first energy storage group and the second energy storage group.

[0014] In some embodiments, the power adjustment module includes:

[0015] A battery energy storage system control unit, configured to determine the power output by the first energy storage group and the second energy storage group in the energy storage system according to the last truly compensated power.

[0016] A compensation adjustment unit, configured to determine the energy state difference between the power to be compensated and the first energy storage group and the second energy storage group, and determine the truly compensated power this time according to the result of performing gain processing on the energy state difference by using a preset time constant; wherein, the preset time constant is used to adjust the response rate of the power output by the first energy storage group and the second energy storage group to the power to be compensated.

[0017] In some embodiments, the compensation adjustment unit includes:

[0018] An energy state deviation acquisition sub-unit, configured to acquire the energy state deviation between the energy charged into the first energy storage group and the energy output by the second energy storage group.

[0019] An energy state difference acquisition sub-unit, configured to determine the energy state difference according to the power to be compensated and the energy state deviation.

[0020] A compensation determination sub-unit, configured to determine the truly compensated power this time according to the result of performing gain processing on the energy state difference by using a preset time constant.

[0021] In some embodiments, the energy state deviation acquisition sub-unit is further configured to perform integral calculation on the power charged into the first energy storage group to obtain a first energy state, perform integral calculation on the power output by the second energy storage group to obtain a second energy state, and determine the difference between the first energy state and the second energy state as the energy state deviation.

[0022] In some embodiments, the energy state difference acquisition subunit is further configured to perform an integration operation on the power to be compensated to obtain a third energy state, and determine the difference between the third energy state and the energy state deviation as the energy state difference.

[0023] In some embodiments, the compensation determination subunit is further configured to perform a gain process on the energy state difference by using a preset time constant to obtain a set power difference, and determine the actual compensation power for this time according to the superimposed power of the set power difference and the power to be compensated.

[0024] In some embodiments, the compensation determination subunit is further configured to obtain the power loss of the energy storage system, and determine the difference between the superimposed power and the power loss as the actual compensation power for this time.

[0025] In a second aspect, the present application provides a new energy system, which includes a new energy power generation system, an energy storage system, a power grid system, and the new energy dual energy storage system safety and stable operation control device according to any one of the first aspect. The new energy power generation system, the energy storage system, and the power grid system are all connected to the new energy dual energy storage system safety and stable operation control device.

[0026] In the technical solution provided by the embodiments of the present application, by using at least a two-stage high-pass filter module to process the power generated by the new energy power generation system, the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system can be filtered out, effectively controlling the influence of the unbalanced charge and discharge energy on the operation state of the dual energy storage system during the process of the dual energy storage system smoothing the power generation power of the new energy power generation system, enabling the increase and decrease of the energy state of the dual energy storage system to be synchronized, making full use of the cycle life to extend the operation life of the dual energy storage system, and avoiding the situation where the dual energy storage system cannot operate safely and stably when working at a high energy state or a low energy state simultaneously. Therefore, the technical solution provided by the embodiments of the present application can improve the stability and safety of the operation of the dual energy storage system. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0028] Figure 1 It is a schematic structural diagram of the new energy system provided for some embodiments;

[0029] Figure 2Schematic diagram of a dual energy storage system provided for some embodiments operating at a high energy boundary for a long time as time increases;

[0030] Figure 3 Schematic diagram of a dual energy storage system provided for some embodiments operating at a low energy boundary for a long time as time increases;

[0031] Figure 4 Schematic diagram of the structure of a control device for the safe and stable operation of a new energy dual energy storage system provided for the first embodiment;

[0032] Figure 5 Schematic diagram of the structure of a control device for the safe and stable operation of a new energy dual energy storage system provided for the second embodiment;

[0033] Figure 6 Schematic diagram of the structure of a control device for the safe and stable operation of a new energy dual energy storage system provided for the third embodiment;

[0034] Figure 7 Schematic diagram of the relationship between the SOC and time variation of a dual energy storage system controlled by a first-order low-pass filter scheme provided for some embodiments;

[0035] Figure 8 Schematic diagram of the relationship between the SOC and time variation of a dual energy storage system with optimized control using a first-order low-pass filter scheme provided for some embodiments;

[0036] Figure 9 Schematic diagram of the relationship between the SOC and time variation of a dual energy storage system controlled by a second-order high-pass filter scheme provided for the embodiments of the present application. Detailed implementation manners

[0037] The embodiments of the technical solution of the present application will be described in detail below with reference to the accompanying drawings. The following embodiments are only used to illustrate the technical solution of the present application more clearly, so they are only examples and cannot be used to limit the protection scope of the present application.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used herein are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification and claims of this application and the above drawings are intended to cover non-exclusive inclusion.

[0039] In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity, specific order, or primary-secondary relationship of the indicated technical features. In the description of the embodiments of the present application, the meaning of "a plurality" is more than two, unless otherwise clearly and specifically defined. In the description of the embodiments of the present application, "each" means every one or every one of a plurality, unless otherwise clearly and specifically defined.

[0040] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in connection with the embodiments can be included in at least one embodiment of the present application. The phrase appears in various places in the specification and does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment mutually exclusive with other embodiments. Those skilled in the art will explicitly and implicitly understand that the embodiments described herein can be combined with other embodiments.

[0041] In the description of the embodiments of the present application, the term "and / or" is merely a description of the association relationship of associated objects, indicating that three relationships can exist. For example, A and / or B can represent three situations: A exists alone, A and B exist simultaneously, and B exists alone. Additionally, the character " / " in this document generally represents an "or" relationship between the associated objects before and after.

[0042] For an energy storage system, the main factors affecting its operating life include depth of discharge, number of charge and discharge cycles, etc. The power generated by new energy fluctuates randomly. During the process of canceling the fluctuating power of the new energy power generation system, the energy storage system needs to frequently switch between charge and discharge to track and cancel the fluctuating power of the new energy power generation system, resulting in an increase in the number of charge and discharge cycles of the energy storage system, which greatly affects its operating life.

[0043] In some embodiments, it is proposed to divide the energy storage system into two parallel energy storage groups in advance. These two energy storage groups are independently controlled respectively. One energy storage group is used for discharging, and one energy storage group is used for charging. When a certain energy storage group is fully charged or discharged, the charge and discharge of the two energy storage groups are switched, so as to avoid frequent charge and discharge switching during the operation of the energy storage system, extend the operating life, and when the depth of discharge of the energy storage group during operation is relatively large, its energy utilization rate is higher and the damage to its operating life is smaller.

[0044] However, dividing the energy storage system into two energy storage groups for control contributes to extending the operating life of the energy storage system. However, due to the random volatility of the output (i.e., the generated power) of the new energy power generation system, there may be a phenomenon of imbalance between charging and discharging energy during the operation of the energy storage system, causing the energy storage system to operate in extreme situations of high energy state (corresponding to the State of Charge (SOC)) or low energy state, which will affect its life and operating performance.

[0045] The embodiment of the present application proposes a control device for the safe and stable operation of a new energy dual energy storage system considering extreme operating conditions, which greatly reduces the imbalance degree of charging and discharging energy and avoids the extreme situations of the dual energy storage operating in high energy state or low energy state. In some embodiments, a power adjustment link based on energy state feedback is also proposed to enable the increase and decrease of the energy state of the dual energy storage system to be synchronized, so as to improve the utilization rate of the operating life.

[0046] The dual energy storage system provided by the embodiment of the present application includes a first energy storage group and a second energy storage group.

[0047] Figure 1 The structural schematic diagram of the new energy system provided for some embodiments is as Figure 1 shown. The new energy system includes: a new energy power generation system, an energy storage system, a power grid system, and a control device for the safe and stable operation of the new energy dual energy storage system. The new energy power generation system, the energy storage system, and the power grid system are all connected to the control device for the safe and stable operation of the new energy dual energy storage system (which can also be called an energy storage controller).

[0048] The new energy power generation system is a system that can generate electricity through new energy technologies. The new energy power generation system may include at least one of the following: a photovoltaic power generation system, a wind power generation system, a hydropower generation system, a tidal energy power generation system, or a biomass energy power generation system, etc. The new energy power generation system can supply power to the energy storage system and can also directly output electric energy to the power grid system to supply power to the power grid system. The energy storage system can also supply power to the power grid system.

[0049] In Figure 1 's embodiment, P w is the wind power output (also known as the power generated by the wind power generation system), P pv is the photovoltaic power output (also known as the power generated by the photovoltaic power generation system); the energy storage is divided into two parts for control to reduce the life loss during the process of smoothing the new energy power. Among them, P b1 , P b2 are the charging and discharging powers of the first energy storage group and the second energy storage group respectively; P g is the actual grid-connected power. The control device for the safe and stable operation of the new energy dual energy storage system determines the charging and discharging tasks of the two energy storage groups according to the power generated by the new energy power generation system and the operating state of the energy storage system.

[0050] In any embodiment of the present application, the control device for the safe and stable operation of the new energy dual energy storage system may include an energy storage controller.

[0051] In the embodiments of the application, technicians have noticed that there is a phase lag in the process of the energy storage system smoothing the power generation power of the new energy system. For example, there is a phase difference between the grid-connected power P g and the output power P w of the wind power generation system, resulting in a DC component in the difference between the grid-connected power P g and the output power P w of the wind power generation system. The cumulative value of this DC component affects the operation state of the dual energy storage system. In the long run, the two energy storage groups will operate at the boundary of high energy or low energy states for a long time, which will affect the service life and charge (discharge) capacity of the energy storage system.

[0052] The combined output of the new energy energy storage system is the sum of the power generation power of the new energy power generation system and the power of the energy storage system. Taking the positive direction as the energy storage system discharging, taking the Figure 1 embodiment shown as an example, the grid-connected power can be obtained as . Among them, is the output power of the photovoltaic power generation system, is the actual output power of the first energy storage group (or the output after loss), the actual output power of the second energy storage group.

[0053] The actual output power of the first energy storage group can be obtained by the following method: ; among them, is the ideal power of the first energy storage group (or the output that needs to be provided), is the charge and discharge efficiency of the energy storage system.

[0054] The actual output power of the second energy storage group can be obtained by the following method: ; among them, the ideal power of the second energy storage group.

[0055] The charge and discharge power loss of the first energy storage group during the charge and discharge process of the energy storage system is: ; the charge and discharge power loss of the second energy storage group is: .

[0056] To effectively reduce the life loss caused by the frequent charge-discharge conversion of the energy storage system and extend its operating life, the energy storage system is evenly divided into a first energy storage group and a second energy storage group that independently track the charging and discharging powers for control. The rated capacity of each energy storage group is half of the energy storage system, and the charging or discharging state is determined according to the energy state values of the two energy storage groups.

[0057] Exemplarily, at the initial operation, it is assumed that the first energy storage group independently tracks the charging power and the second energy storage group independently tracks the discharging power (and vice versa). The initial energy state values of the first energy storage group and the second energy storage group are respectively E1(0) = (1 - E ref ) / 2, E2(0) = (1 + E ref ) / 2, where E ref is the optimal operating energy state. During the operation, the power constraints of the two energy storage groups are .

[0058] , and ;

[0059] where, is the actual output power of the first energy storage group at the t-th moment, is the actual output power of the second energy storage group at the t-th moment; , are respectively the maximum charging and discharging powers of each energy storage group at the t-th moment considering the energy storage rated power and energy state constraints; P br is the rated power of each energy storage group; is the control period or sampling period of the energy storage system; is the energy state of the first energy storage group at the t-th moment, is the energy state of the second energy storage group at the t-th moment, is the energy state of the first energy storage group at the (t - 1)-th moment, is the energy state of the second energy storage group at the (t - 1)-th moment.

[0060] In some embodiments, one of the two energy storage groups is used for discharging and the other is used for charging. In some embodiments, when one energy storage group cannot meet the required compensated power, the two energy storage groups can charge and discharge together.

[0061] When the energy state of the first energy storage group reaches E1 = (1 + E ref ) / 2 or the energy state of the second energy storage group reaches E2 = (1 - E ref) / 2, switch the charge-discharge working modes of the two energy storage groups, that is, the first energy storage group tracks the discharge power and the second energy storage group tracks the charging power. When both energy storage groups can operate in the optimal energy state, the following can be achieved: (a) maintaining sufficient charge-discharge capacity to ensure the ability to smooth the power generation of the subsequent new energy power generation system; (b) simultaneously reaching the set value boundary of the energy storage energy state and making full use of its cycle life to extend the operation life.

[0062] Smoothing the power generation of a new energy power generation system means regulating and controlling the power fluctuations generated during the new energy power generation process through various technical means and methods, making its output power more stable and smooth, reducing the rapid changes and large fluctuations in power, and approaching a relatively constant power value as much as possible or outputting according to a predetermined power curve. When smoothing the power generation of a new energy power generation system, due to the existence of a DC component in the difference between the grid-connected power and the output power of the wind power generation system, the total charge-discharge energy of the two energy storage groups is unbalanced during the operation cycle, and in most cases, it is difficult for their energy states to reach the set value simultaneously. To prevent the two energy storage groups from operating in overcharge or over-discharge states, when the energy state of the first energy storage group or the second energy storage group reaches the set value, switch their charging and discharging modes.

[0063] Figure 2 Schematic diagram of a dual energy storage system provided for some embodiments operating at a high energy boundary for a long time as time goes by, Figure 3 Schematic diagram of a dual energy storage system provided for some embodiments operating at a low energy boundary for a long time as time goes by.

[0064] Take Figure 2 During the process of smoothing the power generation of a new energy power generation system, for example, when the charging energy of the dual energy storage system is greater than the discharging energy: when the energy storage group in the charging state reaches the upper limit of the energy state, the energy storage group in the discharging state still remains near the upper limit of the energy state because its discharging energy is less. At this time, the charge-discharge working modes of the two energy storage groups are switched, and the energy storage group in the discharging state will track the charging power. Its remaining rechargeable energy is less, and the charge-discharge modes of the two energy storage groups will be switched again soon. When the energy states of the two energy storage groups reach the upper limit of the energy state simultaneously, they will enter an extreme state of frequent charge-discharge mode switching. At this time, the dual energy storage system hardly has the charging ability, it is difficult to track the charging power to smooth the power generation of the new energy power generation system with positive fluctuations, and long-term operation at a high energy state will affect the life of the dual energy storage system. Figure 3 The analysis of Figure 2 is similar to that of

[0065] Therefore, it is necessary to propose a suitable control strategy to control the phase difference between the grid-connected power and the power generation power of the new energy power generation system, so as to effectively control the influence of the unbalanced charge-discharge energy on the operation state during the process of the dual energy storage system smoothing the power generation power of the new energy power generation system, and enable the increase and decrease of the energy state of the dual energy storage system to be synchronized to fully utilize the cycle life and extend the operation life.

[0066] Considering the influence of the unbalanced charge-discharge energy on the operation of the dual energy storage system, in one embodiment of the present application, an energy storage optimization control strategy is proposed, aiming to reduce the phase lag during the power smoothing process, with a DC component existing in the difference between the grid-connected power and the output power of the wind power generation system. In another embodiment, by adding an energy feedback control link to adjust the charge-discharge power of the energy storage, the increase and decrease of the energy state of the dual energy storage system can be synchronized.

[0067] Figure 4 The structural schematic diagram of the control device for the safe and stable operation of the new energy dual energy storage system provided for the first embodiment is as Figure 4 shown. The control device 10 for the safe and stable operation of the new energy dual energy storage system includes a power processing device 11 and a power superposition device 12.

[0068] The power processing device 11 is used to process the power P w (s) generated by the new energy power generation system by using at least a two-stage high-pass filter module 111 to obtain the power to be compensated, and determine the truly compensated power P b (s) of the first energy storage group and the second energy storage group in the energy storage system according to the power to be compensated; the power superposition device 12 is used to superpose the power generated by the new energy power generation system and the truly compensated power to obtain the grid-connected power P g (s) output to the power grid system. Among them, the at least two-stage high-pass filter module 111 is used to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system.

[0069] The embodiment of the present application does not limit the order of the at least two-stage high-pass filter module 111. For example, the at least two-stage high-pass filter module 111 may include a second-order high-pass filter module, a third-order high-pass filter module, a fourth-order high-pass filter module, and so on.

[0070] In some embodiments, the order of the at least two-stage high-pass filter module 111 can be flexibly configured according to the use of the grid-connected power. For example, in the case where a better filtering effect on the DC component is required, the order of the at least two-stage high-pass filter module 111 can be increased, and in the case where the complexity of the filtering needs to be reduced, the order of the at least two-stage high-pass filter module 111 can be reduced.

[0071] In some embodiments, the control device 10 for the safe and stable operation of the new energy dual energy storage system may further include a battery energy storage system control unit, and the battery energy storage system control unit may switch the order of at least two-order high-pass filter modules 111. Exemplarily, the battery energy storage system control unit may receive an order modification instruction sent by the host computer, and the order modification instruction carries the modified order, so that the battery energy storage system control unit adjusts the order of at least two-order high-pass filter modules 111.

[0072] In some embodiments, the power actually compensated by the first energy storage group and the second energy storage group is one is 0 and the other is non-0. A positive value of the actually compensated power indicates that the energy storage group is a discharging energy storage group, and a negative value of the actually compensated power indicates that the energy storage group is a charging energy storage group.

[0073] Exemplarily, the power superposition device 12 may include an adder.

[0074] In the technical solution provided by the embodiments of the present application, a high-pass filter module with at least two orders is used to process the power generated by the new energy power generation system, which can filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system, effectively control the influence of the unbalanced charge and discharge energy on the operating state of the dual energy storage system during the process of smoothing the power generation power of the new energy power generation system, enable the increase and decrease of the energy state of the dual energy storage system to be synchronized, make full use of the cycle life to extend the operating life of the dual energy storage system, and avoid the dual energy storage system from operating at a high energy state or a low energy state at the same time, resulting in the dual energy storage system being unable to operate safely and stably. Therefore, the technical solution provided by the embodiments of the present application can improve the stability and safety of the operation of the dual energy storage system.

[0075] The following is the reasoning process of the above technical effects:

[0076] In order to uniformly describe the unbalanced state of the charge and discharge energy of the two energy storage groups during the process of smoothing the power generation power of the new energy power generation system, it is defined by taking the difference between the upper limit of the energy state and the energy state of the energy storage group in the charging state, and the energy state of the discharging energy storage group and the lower limit of the energy state. 。 The energy imbalance degree index of the energy storage system operation is represented by , where ; . Among them is the energy imbalance degree index of the energy storage system operation at the t-th moment; , are the remaining rechargeable and dischargeable energies of the charging energy storage group and the discharging energy storage group at the t-th moment respectively; E ref is the optimal operating energy state; represents the energy state of the energy storage group in the charging state at the t-th moment; Indicates the energy state of the energy storage group representing the discharge state at time t; since both energy storage group 1 and energy storage group 2 act as charge and discharge roles during operation, the energy storage group in the charging state is used to represent here.

[0077] The following embodiments are explained by a new energy power generation system including a wind power generation system. In other embodiments, similar to the following explanation, the new energy power generation system may include a wind power generation system and a photovoltaic power generation system.

[0078] Through , and , another , equals 1, = , the following formula (1) can be derived:

[0079] (1);

[0080] Among them, and respectively represent the initial energy states of the charging energy storage group and the discharging energy storage group at the initial moment, which are E1(0)=(1 - E ref ) / 2 and E2(0)=(1 + E ref ) / 2 as described above.

[0081] Taking the Laplace transform of formula (1) gives , and according to = the formula (2) is obtained:

[0082] (2);

[0083] E un (s) is the transfer function of the unbalanced energy of the dual energy storage system, or rather the representation in the complex frequency domain (s domain); , , respectively represent the transfer function of the grid-connected power, the transfer function of the power generated by the wind power generation system, and the transfer function of the power generated by the energy storage system. G g (s), G b (s) are respectively the transfer function of the smoothed power and the control transfer function of the dual energy storage system, satisfying G g (s) - G b (s) = 1; G b1 (s), G b2 (s) are respectively the control transfer functions of the first energy storage group and the second energy storage group.

[0084] The unbalanced energy during the long-term operation of the dual energy storage system mainly comes from the power fluctuation component of the new energy power generation system it compensates. The cumulative value of its AC component, that is, the periodic component, is zero and does not affect the energy state of the dual energy storage system during operation. However, the accumulation of the DC component will continuously increase the unbalanced energy in the positive or negative direction, ultimately leading to the extreme situation where the two energy storage groups operate in a high (low) energy state.

[0085] Applying the final value theorem to formula (2), the final change trend of the unbalanced energy of the dual energy storage system can be obtained as formula (3):

[0086] (3).

[0087] Among them, the DC component is a constant that does not cross zero and is greater than 0, denoted as C, and its transfer function is C / s. If includes the DC component, then includes C / s. From formula (3), it can be seen that if including C / s is to be eliminated, the order must be greater than the second order to make tend to 0 to achieve the purpose of eliminating the DC component.

[0088] That is to say, there is inevitably a DC component in the power generation power of the new energy power generation system, that is, a unidirectional changing power that does not cross zero. To make the unbalanced energy E un change in the direction of 0, the transfer function G b (s) of the power output by the energy storage system should have an order not less than the second order.

[0089] Therefore, a high-pass filter with an order greater than or equal to the second order can filter out the DC component existing in the difference between the grid-connected power and the output power of the wind power generation system, reducing the additional time required to process the DC component, thereby increasing the phase lag. And due to the DC component existing in the difference between the grid-connected power and the output power of the wind power generation system, the energy storage system does not need to increase its output to compensate for this part of the DC component, thus reducing the output of the energy storage system. In addition, by filtering out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system, it effectively controls the influence of the unbalanced charge-discharge energy on the operating state of the dual energy storage system during the process of smoothing the power generation power of the new energy power generation system by the dual energy storage system, enabling the increase and decrease of the energy state of the dual energy storage system to be synchronized, making full use of the cycle life to extend the operating life of the dual energy storage system, and avoiding the situation where the dual energy storage system cannot operate safely and stably when working in a high energy state or a low energy state at the same time. Therefore, the technical solution provided by the embodiments of the present application can improve the stability and security of the operation of the dual energy storage system.

[0090] In some embodiments, to meet the requirements of the controller order, an embodiment of the present application proposes a transfer function of the power generated by a general energy storage system that meets the requirements. At the same time, the control structure and parameter design are simplified for real-time application, and the second order is selected as the end in the transfer function of the power generated by the energy storage system.

[0091] Exemplarily, the expression of the transfer function of the power generated by the energy storage system is , is the order of G b (s). If the order of G b (s) is selected as 2, then this expression is converted into formula (4):

[0092] (4);

[0093] Wherein, ; wherein, g b is the gain; F FHF is the standard first-order high-pass filter link; T b is the filter time constant; k1 and k2 are both control parameters.

[0094] Through formula (4), by adjusting the two parameters of the gain and the filter time constant, a controller that meets the power smoothing requirements of the new energy power generation system and the control requirements of the dual energy storage system can be designed (this controller is realized through G b (s)).

[0095] The power fluctuation of the new energy power generation system is usually in the range of seconds to minutes. During the process of energy storage smoothing power, it is necessary to ensure that the smoothed grid-connected power can meet the national wind power grid connection standard. In some embodiments, the filter time constant can be determined by the method of first-order high-pass filter adaptive simulation. When applied to actual engineering, the time constant can be determined according to the fluctuation characteristics contained in the historical power of the wind farm, with the constraint of meeting certain confidence requirements.

[0096] The physical meaning of the gain g b is analyzed as follows. Taking the new energy power generation system including the wind power generation system as an example, there is ; wherein, are the grid-connected power, the power generated by the wind power generation system, and the power generated by the battery system at time t, respectively. Performing Laplace transform on obtains ; wherein, = , and then formula (5) is obtained:

[0097] (5);

[0098] It can be seen from formula (5) that Affecting the high-frequency components contained in the grid-connected power, on the premise of meeting the requirements for smoothing the power generation of the new energy power generation system, controlling this parameter can reduce the output of the dual energy storage system to a certain extent, so as to reduce the capacity requirements and operating losses of the dual energy storage system.

[0099] In the embodiments of the present application, without special instructions, power refers to dynamic power, which changes with time. In the embodiments of the present application, the power generated by the new energy power generation system, the truly compensated power, and the grid-connected power can be represented in the complex domain (s-domain) (also known as the transfer function of power). For example, the power generated by the new energy power generation system is represented as , the truly compensated power is represented as , and the grid-connected power is represented as .

[0100] Figure 5 FIG. is a schematic structural diagram of the control device for the safe and stable operation of the new energy dual energy storage system provided in the second embodiment, as Figure 5 shown, Figure 5 The embodiment has the following further features on the basis of the Figure 4 embodiment: A power processing device 11, including: a high-pass filter module 111 with at least two orders and a power adjustment module 112; the high-pass filter module 111 with at least two orders is used to process the power generated by the new energy power generation system to obtain the power that needs to be compensated; the power adjustment module 112 is used to determine the power output by the first energy storage group and the second energy storage group in the energy storage system according to the power that needs to be compensated, and adjust the power output by the first energy storage group and the second energy storage group to obtain the truly compensated power.

[0101] In some embodiments, the high-pass filter module 111 with at least two orders can be determined according to the standard high-pass filter module with at least two orders. For example, the high-pass filter module 111 with at least two orders is used to process the power generated by the new energy power generation system by using a filter transfer function to obtain the power that needs to be compensated. Exemplarily, the filter transfer function can be , where n is an integer greater than or equal to 2. Another example is that the filter transfer function can be , where m is an integer greater than or equal to 2.

[0102] In the embodiments of the present application, processing power by using a transfer function may include multiplying the power by the transfer function.

[0103] In some embodiments, the method for determining the charging power of the charging battery pack or the discharging power of the discharging battery pack is:

[0104] ;

[0105] ;

[0106] Wherein, is the charging power of the rechargeable battery pack at the current time t, is the power to be compensated for charging at the current time t (i.e., the power that needs to be compensated as described above), , are the rated power and rated capacity of the dual-battery energy storage system respectively, , are the maximum and minimum values of the state of charge of the battery pack respectively, is the working efficiency of the battery pack, is the execution time of the single charging or discharging power command, is the charging battery pack at time state of charge. is the discharging power of the discharging battery pack at the current time t, is the power to be compensated for discharging at the current time t, is the discharging battery pack at time state of charge.

[0107] In some embodiments, the power adjustment module 112 may include an energy feedback control link, and through the energy feedback control link, it is realized that: according to the power that needs to be compensated, the power output by the first energy storage group and the second energy storage group in the energy storage system is determined, and the power output by the first energy storage group and the second energy storage group is adjusted to obtain the truly compensated power.

[0108] Figure 6 is a schematic structural diagram of the new energy dual energy storage system safety and stability operation control device provided by the third embodiment, as Figure 5 shown, Figure 6 The embodiment, on the basis of the Figure 5 embodiment, further has the following features: The high-pass filter module 111 with at least two orders includes: a second-order high-pass filter unit 1111, which is used to filter the power generated by the new energy power generation system to obtain the filtered power; a gain unit 1112, which is used to perform gain processing on the filtered power by using the target gain g b to obtain the power that needs to be compensated. Among them, the second-order high-pass filter unit is used to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system. Among them, the target gain is used to adjust the energy storage output power of the first energy storage group and the second energy storage group.

[0109] In some embodiments, the second-order high-pass filter unit 1111 may be a second-order standard high-pass filter unit. For example, the second-order high-pass filter unit 1111 is used to process the power generated by the new energy power generation system using the transfer function of the second-order high-pass filter to obtain the power to be compensated. The transfer function of the second-order high-pass filter may be or expressed in the following way .

[0110] Exemplarily, the target gain may be a real number in the range of 0 to 1. In some embodiments, the magnitude of the target gain can be adjusted to adjust the output of the dual energy storage system. For example, by increasing the target gain, the output of the dual energy storage system can be reduced. Conversely, by reducing the target gain, the output of the dual energy storage system can be increased.

[0111] In the embodiments of the present application, the filtered power is subjected to gain processing using the target gain, which can adjust the output of the dual energy storage system to reduce the capacity requirement and operating loss of the dual energy storage system. Among them, the target gain may be the above-mentioned . According to the above formula it can be seen that by increasing , becomes lower, so that the amplification factor of the high-frequency signal will decrease, and thus the amplification factor of the power generated by the new energy power generation will decrease, thereby reducing the output of the dual energy storage system.

[0112] Figure 6 The embodiment has the following further features on the basis of the Figure 5 embodiment: The power adjustment module 112 includes: a battery energy storage system (BESS) control unit 1121 (also referred to as the BESS controller) and a compensation adjustment unit 1122.

[0113] The battery energy storage system control unit 1121 is used to determine the power output by the first energy storage group and the second energy storage group in the energy storage system according to the power of the previous actual compensation;

[0114] The compensation adjustment unit 1122 is used to determine the energy state difference between the power to be compensated and the first energy storage group and the second energy storage group, and determine the actual compensation power this time according to the result of performing gain processing on the energy state difference using a preset time constant; wherein the preset time constant is used to adjust the response rate of the power output by the first energy storage group and the second energy storage group to the power to be compensated.

[0115] In some embodiments, determining the power to be compensated and the energy state difference between the first energy storage group and the second energy storage group may include: determining the energy state deviation between the first energy storage group and the second energy storage group, and determining the energy state difference based on the power to be compensated and the energy state deviation. Exemplarily, the energy state deviation between the energy charged into the first energy storage group and the energy output from the second energy storage group may be obtained. Additionally, the energy state deviation between the current energy state of the first energy storage group and the current energy state of the second energy storage group may be obtained.

[0116] Exemplarily, the battery energy storage system control unit 1121 may be configured to, based on whether the power to be compensated is the power to be compensated for discharging or the power to be compensated for charging, select one of the first energy storage group and the second energy storage group, and determine the energy charged into or released from the selected energy storage group based on the power to be compensated, and determine that the power output from the other energy storage group is 0. For example, at the current moment, the first energy storage group is the charging energy storage group and the second energy storage group is the discharging energy storage group. Herein, the selected energy storage group is the energy storage group that matches the power to be compensated. For example, in the case of compensating for the discharging power, the selected energy storage group should be the energy storage group that independently tracks the discharging power. Herein, when an energy storage group needs to output power, it is determined that the energy storage group discharges energy, and when an energy storage group needs to absorb power, it is determined that the energy storage group charges energy.

[0117] In some embodiments, the battery energy storage system control unit 1121 may directly determine the power to be compensated as the power charged into or output from the selected energy storage group.

[0118] In other embodiments, the battery energy storage system control unit 1121 may determine the power charged into or output from the selected energy storage group based on the current energy states of the first energy storage group and the second energy storage group and / or based on at least one previous actual compensated power, and based on the power to be compensated. For example, the battery energy storage system control unit 1121 may determine the power charged into or output from the selected energy storage group based on the current energy states of the first energy storage group and the second energy storage group and based on the power to be compensated. In still other embodiments, the battery energy storage system control unit 1121 may determine the power charged into or output from the selected energy storage group based on the previous actual compensated power and the previous power to be compensated, and based on the power to be compensated.

[0119] Among them, the energy state difference is processed by a preset time constant to perform gain processing. Therefore, when the preset time constant is large, the true compensated power is also large. The battery energy storage system control unit can determine the power output by the first energy storage group and the second energy storage group in the energy storage system this time according to the previous large true compensated power and the power output by the first energy storage group and the second energy storage group, so that the response rate to the power to be compensated is higher, thereby realizing the function of flexibly adjusting the response rate of the power output by the first energy storage group and the second energy storage group to the power to be compensated.

[0120] In some embodiments, the battery energy storage system control unit 1121 can also adjust the preset time constant according to the power consumption stability demand information.

[0121] In the technical solution provided by the embodiment of the present application, the power to be compensated and the energy state difference between the first energy storage group and the second energy storage group are determined, and the true compensated power this time is determined according to the result of performing gain processing on the energy state difference by a preset time constant, so that the true compensated power can match the power to be compensated.

[0122] Figure 6 The embodiment is based on Figure 5 On the basis of the embodiment, it further has the following features: The compensation adjustment unit 1122 includes: an energy state deviation acquisition subunit 1122a, an energy state difference acquisition subunit 1122b, and a compensation determination subunit 1122c.

[0123] The energy state deviation acquisition subunit 1122a is configured to acquire the energy state deviation between the energy charged into the first energy storage group and the energy output by the second energy storage group;

[0124] The energy state difference acquisition subunit 1122b is configured to determine the energy state difference according to the power to be compensated and the energy state deviation;

[0125] The compensation determination subunit 1122c is configured to determine the true compensated power this time according to the result of performing gain processing on the energy state difference by a preset time constant.

[0126] Exemplarily, the first energy storage group may be a charging energy storage group, and the power charged into the charging energy storage group is expressed as P ch (s), and the energy charged into the first energy storage group can be obtained by performing an integral operation on P ch (s). Exemplarily, the second energy storage group is a discharging energy storage group, and the power output by the discharging energy storage group is expressed as P dis (s), and the energy released by the second energy storage group can be obtained by performing an integral operation on P dis (s).

[0127] In some embodiments, the energy state difference may be determined as the power for true compensation.

[0128] In the technical solution provided by the embodiments of the present application, according to the energy state difference, the power for true compensation is determined, so that the accurate power for true compensation can be calculated.

[0129] In some embodiments, the energy state deviation acquisition subunit 1122a is further configured to perform an integration calculation on the power charged into the first energy storage group to obtain a first energy state, perform an integration calculation on the power output by the second energy storage group to obtain a second energy state, and determine the difference between the first energy state and the second energy state as the energy state deviation.

[0130] Exemplarily, performing an integration operation on the output power may be to process the charged / output power using the transfer function 1 / s.

[0131] In some embodiments, the energy state deviation acquisition subunit 1122a may be configured to perform an integration process on the power charged into the first energy storage group, for example Figure 6 processed using the transfer function 1 / s in, to obtain a first energy state, perform an integration process on the power output by the second energy storage group, for example Figure 6 processed using the transfer function 1 / s in, to obtain a second energy state.

[0132] In the technical solution provided by the embodiments of the present application, by performing an integration operation on the powers of the first energy storage group and the second energy storage group, the cumulative powers of the first output power and the second output power over time, that is, the first energy state and the second energy state, can be obtained respectively, which is beneficial to determining the energy state deviation between the first energy storage group and the second energy storage group, and is beneficial for the battery energy storage system control unit 1121 to determine the next power charging / output of the energy storage group, so that the amount of electricity charged into the energy storage group for charging and the amount of electricity discharged by the energy storage group for discharging in the two energy storage groups are as synchronous as possible, which is beneficial to making full use of the cycle life of the first energy storage group and the second energy storage group and extending the operation life of the first energy storage group and the second energy storage group.

[0133] In some embodiments, the energy state difference acquisition subunit 1122b is further configured to perform an integration operation on the power to be compensated to obtain a third energy state, and determine the energy state difference as the difference between the third energy state and the energy state deviation.

[0134] Exemplarily, performing an integration operation on the power to be compensated may be to process the power to be compensated using the transfer function 1 / s.

[0135] In the technical solution provided by the embodiment of the present application, by performing an integration operation on the power to be compensated, the cumulative power of the power to be compensated over time, that is, the third energy state, can be obtained. Thus, subsequent adjustment of the output power of the first energy storage group and the second energy storage group can be performed based on the cumulative power of the power to be compensated over time and the difference in the cumulative power of the first energy state and the second energy state over time, improving the reliability of the output power.

[0136] In some embodiments, the compensation determination subunit 1122c is further configured to perform a gain process on the energy state difference using a preset time constant g1 to obtain a set power difference, and determine the actual compensated power for this time based on the superimposed power of the set power difference and the power to be compensated.

[0137] Exemplarily, the preset time constant can be a real number within the range of 0 to 1. The preset time constant is used to adjust the response rate of the power output by the first energy storage group and the second energy storage group determined by the battery energy storage system control unit 1121 to the power to be compensated. For example, when the preset time constant is larger, the response speed of the battery energy storage system control unit 1121 to the power to be compensated is also faster, so that the actual compensated power is closer to the power to be compensated. Another example is that when the preset time constant is smaller, the response speed of the battery energy storage system control unit 1121 to the power to be compensated is also slower, so that the difference between the actual compensated power and the power to be compensated is larger.

[0138] In the technical solution provided by the embodiment of the present application, by performing a gain process on the energy state difference using a preset time constant, the response speed of the battery energy storage system control unit 1121 to the power to be compensated can be flexibly adjusted.

[0139] In some embodiments, the compensation determination subunit 1122c is further configured to obtain the power loss P of the energy storage system loss , and determine the difference between the superimposed power and the power loss as the actual compensated power for this time.

[0140] Among them, the power loss can be the charge and discharge power loss of the energy storage group with a non-zero output power. The calculation methods of the charge and discharge power losses of the first energy storage group and the second energy storage group can be referred to the above description and will not be elaborated here.

[0141] In Figure 6 In another embodiment other than the embodiments, the compensation determination subunit does not include the preset time constant g1, and the compensation determination subunit is configured to determine the actual compensated power based on the superimposed power of the energy state difference and the power to be compensated.

[0142] In some embodiments, through the design of the dual energy storage system controller (i.e., the battery energy storage system control unit 1121 mentioned above), the degree of its energy imbalance can be effectively reduced, avoiding the extreme situation where the two energy storage groups continuously operate in high (low) energy states. Considering the randomness of the power fluctuation of the new energy power generation system and the energy loss due to the charge-discharge efficiency during the operation of the energy storage, a power adjustment link based on the feedback of the unbalanced energy of the dual energy storage is designed to make the unbalanced energy always change in the direction of 0.

[0143] Figure 7 Schematic diagram showing the relationship between the SOC of the dual energy storage system controlled by the first-order low-pass filter scheme provided for some embodiments and the change with time (or moment), in Figure 7 the dual energy storage system compensates for the DC component caused by the phase difference between the grid-connected power of the grid system and the power generated by the new energy power generation system. Figure 8 Schematic diagram showing the relationship between the SOC of the dual energy storage system controlled by the first-order low-pass filter scheme and optimized control provided for some embodiments and the change with time, in Figure 8 the dual energy storage system does not compensate for the DC component caused by the phase difference between the grid-connected power of the grid system and the power generated by the new energy power generation system. Figure 9 Schematic diagram showing the relationship between the SOC of the dual energy storage system controlled by the second-order high-pass filter scheme provided by the embodiments of the present application and the change with time. From Figures 7 to 9 it can be seen that the dual energy storage system controlled by the second-order high-pass filter scheme provided by the embodiments of the present application can not only balance the state of charge released and the energy absorbed in the two energy storage groups, but also reduce the output of the energy storage system, extending the life of the energy storage system.

[0144] The embodiments of the present application also provide a new energy system, which includes a new energy power generation system, an energy storage system, a grid system, and the new energy dual energy storage system safe and stable operation control device of any of the above embodiments. The new energy power generation system, the energy storage system, and the grid system are all connected to the new energy dual energy storage system safe and stable operation control device.

[0145] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in the present application.

[0146] The above embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the patent of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A control device for the safe and stable operation of a new energy dual energy storage system, characterized in that, The device includes: A power processing device, which is used to process the power generated by the new energy power generation system by using at least a two-stage high-pass filter module to obtain the power to be compensated, and determine the actually compensated power of the first energy storage group and the second energy storage group in the energy storage system according to the power to be compensated; wherein, the at least two-stage high-pass filter module is used to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system; A power superposition device, which is used to superpose the power generated by the new energy power generation system and the actually compensated power to obtain the grid-connected power output to the power grid system.

2. The device according to claim 1, characterized in that, The power processing device includes: At least a two-stage high-pass filter module, which is used to process the power generated by the new energy power generation system to obtain the power to be compensated; A power adjustment module, which is used to determine the power output by the first energy storage group and the second energy storage group in the energy storage system according to the power to be compensated, and adjust the power output by the first energy storage group and the second energy storage group to obtain the actually compensated power.

3. The device according to claim 2, characterized in that, The at least two-stage high-pass filter module includes: A second-order high-pass filter unit, which is used to filter the power generated by the new energy power generation system to obtain the filtered power; wherein, the second-order high-pass filter unit is used to filter out the DC component caused by the phase difference between the grid-connected power of the power grid system and the power generated by the new energy power generation system; A gain unit, which is used to perform gain processing on the filtered power by using a target gain to obtain the power to be compensated; wherein, the target gain is used to adjust the energy storage output power of the first energy storage group and the second energy storage group.

4. The device according to claim 2, characterized in that, The power adjustment module includes: A battery energy storage system control unit, which is used to determine the power output by the first energy storage group and the second energy storage group in the energy storage system according to the last actually compensated power; A compensation adjustment unit, which is used to determine the energy state difference between the power to be compensated and the first energy storage group and the second energy storage group, and determine the actually compensated power of this time according to the result of performing gain processing on the energy state difference by using a preset time constant; wherein, the preset time constant is used to adjust the response rate of the power output by the first energy storage group and the second energy storage group to the power to be compensated.

5. The device according to claim 4, characterized in that, The compensation adjustment unit includes: An energy state deviation acquisition sub-unit, which is used to acquire the energy state deviation between the energy charged into the first energy storage group and the energy output by the second energy storage group; An energy state difference acquisition sub-unit, which is used to determine the energy state difference according to the power to be compensated and the energy state deviation; A compensation determination sub-unit, which is used to determine the actually compensated power of this time according to the result of performing gain processing on the energy state difference by using the preset time constant.

6. The device according to claim 5, characterized in that, The energy state deviation acquisition subunit is further configured to perform an integration calculation on the power charged into the first energy storage group to obtain a first energy state, perform an integration calculation on the power output by the second energy storage group to obtain a second energy state, and determine the difference between the first energy state and the second energy state as the energy state deviation.

7. The device according to claim 5, characterized in that The energy state difference acquisition subunit is further configured to perform an integration operation on the power to be compensated to obtain a third energy state, and determine the difference between the third energy state and the energy state deviation as the energy state difference.

8. The device according to claim 5, wherein The compensation determination subunit is further configured to perform a gain process on the energy state difference by using a preset time constant to obtain a set power difference, and determine the actual compensation power for this time according to the superimposed power of the set power difference and the power to be compensated.

9. The device according to claim 8, characterized in that The compensation determination subunit is further configured to obtain the power loss of the energy storage system, and determine the difference between the superimposed power and the power loss as the actual compensation power for this time.

10. A new energy system, characterized in that, The new energy system includes a new energy power generation system, an energy storage system, a power grid system, and the new energy dual energy storage system safety and stable operation control device according to any one of claims 1 to 9. The new energy power generation system, the energy storage system, and the power grid system are all connected to the new energy dual energy storage system safety and stable operation control device.

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