A power control method, device and medium of a three-phase alternating current coupling light storage system

Abstract

The application discloses a power control method and device of a three-phase alternating current coupling light storage system and a medium, relates to the power grid field, and solves the problem of lacking a power control method for realizing input and output balance control in a light storage system, improving power generation of an alternating current coupling light storage system, and improving a self-generation and self-use ratio. Three-phase power of a photovoltaic system, three-phase power of an interactive power distribution cabinet and a power grid are synchronously collected through a current detection device of an energy storage PCS, three-phase load power is derived in combination with preset output power of the energy storage PCS, operation scenes are divided according to the size relationship between three-phase photovoltaic power and corresponding phase load power, when three-phase output power of the energy storage PCS is adjusted through scene division, the actual operation power of N lines is simultaneously satisfied to be less than or equal to the maximum allowable power of the N lines; the absolute value of the output power of each phase of the energy storage PCS is less than or equal to the maximum power of single-phase AC / DC conversion, the stability of the power grid and the light storage system is ensured through N line power limitation and single-phase power limitation, and unbalanced current disturbance is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of power grid, in particular to a power control method and device of a three-phase AC coupling light storage system and a medium. BACKGROUND

[0002] In a three-phase light storage system, there are four key units of photovoltaic system, power conversion system (PCS), battery and load. When the photovoltaic system is connected to the AC bus through a photovoltaic inverter, the entire system is called an AC coupling light storage system. In the system, the photovoltaic system can be a single-phase photovoltaic inverter or a three-phase photovoltaic inverter, and the three-phase photovoltaic inverter is generally a three-phase balanced inverter. The load can be a single-phase load or a three-phase load.

[0003] Therefore, in the entire light storage system, the power of the three phases can be unbalanced, and the unbalanced input or output of the system can cause the following problems: 1. When the light storage system output or input is unbalanced, it will cause an impact on the power grid, and the stability of the power grid and the light storage system will decrease; 2. With the increasing proportion of new energy distribution network, negative electricity price has occurred in many places, and the demand for anti-flow of the light storage system is increasing. If the photovoltaic system in the system is a three-phase balanced output, the photovoltaic output power is limited by the minimum phase load power, and the power generation of the light storage system will decrease; 3. In the self-generation and self-use mode of the light storage system, if the energy storage PCS is balanced input and output, the self-generation and self-use ratio will decrease.

[0004] Therefore, it is necessary to control the input and output balance in the light storage system by a power control method, and to improve the power generation of the AC coupling light storage system and the self-generation and self-use ratio, which is a technical problem to be solved in the art. SUMMARY

[0005] The purpose of the present application is to provide a power control method, device and medium of a three-phase AC coupling light storage system, which solves the problem of lack of a power control method for balancing the input and output in the light storage system, and improving the power generation of the AC coupling light storage system and the self-generation and self-use ratio.

[0006] To solve the above technical problems, the present application provides a power control method of a three-phase AC coupling light storage system, which comprises a photovoltaic system, an energy storage PCS, a battery and a load. The photovoltaic system is connected to an AC bus through an inverter, and the method comprises:

[0007] The current detection device of the energy storage PCS respectively collects the A-phase photovoltaic power, B-phase photovoltaic power and C-phase photovoltaic power output by the photovoltaic system, and collects the A-phase mutual interaction power, B-phase mutual interaction power and C-phase mutual interaction power interacting with the power grid on the side of the power distribution cabinet.

[0008] obtain A-phase load power, B-phase load power and C-phase load power based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual power, the B-phase mutual power, the C-phase mutual power, and A-phase output power, B-phase output power and C-phase output power in the energy storage PCS;

[0009] combined with the maximum allowed power of the system N line and the maximum power of single-phase AC-DC conversion of the energy storage PCS, different operation scenarios are divided according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power;

[0010] The A-phase output power, B-phase output power and C-phase output power of the energy storage PCS are adjusted respectively for different scenarios; wherein the actual operation power of the N line is calculated by a two-phase stationary coordinate system conversion method to ensure that the actual operation power of the N line does not exceed the maximum allowed power of the N line, and the absolute value of the output power of each phase of the energy storage PCS does not exceed the maximum power of single-phase AC-DC conversion.

[0011] As an optional solution, in the power control method of the three-phase AC coupled photovoltaic energy storage system, the A-phase load power, B-phase load power and C-phase load power are obtained based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual power, the B-phase mutual power, the C-phase mutual power, and A-phase output power, B-phase output power and C-phase output power in the energy storage PCS, comprising:

[0012] A-phase load power, B-phase load power and C-phase load power are obtained by the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual power, the B-phase mutual power, the C-phase mutual power, and A-phase output power, B-phase output power and C-phase output power in the energy storage PCS, and a first formula;

[0013] The first formula is:

[0014] ;

[0015] wherein, A-phase load power, B-phase load power and C-phase load power are obtained respectively; The A-phase mutual power, the B-phase mutual power and the C-phase mutual power are obtained respectively; A-phase output power, B-phase output power and C-phase output power in the energy storage PCS are obtained respectively; The A-phase photovoltaic power, the B-phase photovoltaic power and the C-phase photovoltaic power are obtained respectively.

[0016] As an optional solution, in the power control method of the three-phase alternating coupling light storage system, the different operation scenarios include a first scenario: the photovoltaic power of the A phase, the B phase and the C phase is greater than the corresponding phase load power; and correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted for different scenarios, including:

[0017] If the total photovoltaic system power minus the total three-phase load power does not exceed the energy storage system charging limit power, and the absolute value of the power of each phase of the system without adjustment does not exceed the maximum power of the single-phase AC / DC conversion of the energy storage PCS, the A phase, the B phase and the C phase of the energy storage PCS are in the charging state, wherein the charging power of each phase is equal to - (the corresponding phase photovoltaic power) - (the corresponding phase load power).

[0018] If the total photovoltaic system power minus the total three-phase load power exceeds the energy storage system charging limit power, or the absolute value of the power of any phase of the system without adjustment exceeds the maximum power of the single-phase AC / DC conversion of the energy storage PCS, when the anti-reverse flow function is turned on, the total photovoltaic system power is limited to the energy storage system charging limit power through the communication between the energy storage PCS and the photovoltaic system, and the absolute value of the power of each phase is ensured to be less than the maximum power of the single-phase AC / DC conversion of the energy storage PCS.

[0019] As an optional solution, in the power control method of the three-phase alternating coupling light storage system, the different operation scenarios include a second scenario: the photovoltaic power of one phase or two phases is less than the corresponding phase load power; and correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted for different scenarios, including:

[0020] In the second scenario, if the anti-reverse flow function is turned on, the excess phase output power of the photovoltaic system is first absorbed by the energy storage PCS, and then the remaining adjustable power is calculated based on the maximum allowable power of the system N line, and the load power gap of the insufficient phase is supplemented according to the remaining adjustable power;

[0021] If the anti-reverse flow function is not turned on, the load power gap of the insufficient phase is first supplemented by the energy storage PCS, and then the photovoltaic power of the excess phase is absorbed based on the maximum allowable power of the system N line; wherein the excess phase refers to the phase whose photovoltaic power is greater than the corresponding phase load power, and the insufficient phase refers to the phase whose photovoltaic power is less than the corresponding phase load power.

[0022] As an optional solution, in the power control method of the three-phase alternating coupling light storage system, the different operation scenarios include a third scenario: the photovoltaic power of the A phase, the B phase and the C phase is less than the corresponding phase load power; and correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted for different scenarios, including:

[0023] When the absolute value of the system power of any phase is less than the maximum power of the single-phase AC-DC conversion of the energy storage PCS, the gap between the load power and the photovoltaic power of each phase is supplemented by discharging; wherein the discharging power of each phase is determined according to the difference between the corresponding load power and the corresponding photovoltaic power, and the absolute value of the discharging power of each phase does not exceed the maximum power of the single-phase AC-DC conversion of the energy storage PCS.

[0024] As an optional solution, in the power control method of the three-phase AC-coupled photovoltaic energy storage system, the actual operating power of the N line is calculated by a two-phase stationary coordinate system conversion method, including:

[0025] Based on the A-phase output power, the B-phase output power and the C-phase output power of the energy storage PCS, two-phase power components in the two-phase stationary coordinate system are obtained through αβ coordinate transformation;

[0026] The actual operating power of the N line is obtained through the two-phase power components.

[0027] As an optional solution, in the power control method of the three-phase AC-coupled photovoltaic energy storage system, the two-phase power components in the two-phase stationary coordinate system include an α-axis power component and a β-axis power component;

[0028] Correspondingly, the actual operating power of the N line is obtained through the two-phase power components, including:

[0029] The actual operating power of the N line is obtained through the α-axis power component, the β-axis power component and a second formula;

[0030] The second formula is:

[0031] ;

[0032] Wherein, The α-axis power component and the β-axis power component are respectively; The actual operating power of the N line is obtained through the α-axis power component, the β-axis power component and a second formula;

[0033] To solve the above technical problems, the application also provides a power control device for a three-phase AC-coupled photovoltaic energy storage system, the three-phase AC-coupled photovoltaic energy storage system including a photovoltaic system, an energy storage PCS, a battery and a load, the photovoltaic system being connected to an AC bus through an inverter and including:

[0034] A collection module is configured to collect A-phase photovoltaic power, B-phase photovoltaic power and C-phase photovoltaic power output by the photovoltaic system through a current detection device of the energy storage PCS, and collect A-phase mutual interaction power, B-phase mutual interaction power and C-phase mutual interaction power interacting with the power grid on the side of a power distribution cabinet;

[0035] a calculation module, configured to obtain A-phase load power, B-phase load power and C-phase load power based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual power, the B-phase mutual power, the C-phase mutual power, and A-phase output power, B-phase output power and C-phase output power in the energy storage PCS;

[0036] a scenario distinguishing module, configured to distinguish different operation scenarios according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power in combination with the maximum allowed power of the system N line and the single-phase AC / DC conversion maximum power of the energy storage PCS;

[0037] an adjustment module, configured to adjust the A-phase output power, the B-phase output power and the C-phase output power of the energy storage PCS respectively for different scenarios; wherein the actual operation power of the N line is calculated by a two-phase stationary coordinate system conversion method, so as to ensure that the actual operation power of the N line does not exceed the maximum allowed power of the N line, and the absolute value of the output power of each phase of the energy storage PCS does not exceed the single-phase AC / DC conversion maximum power.

[0038] To solve the above technical problems, the application further provides a power control device of a three-phase AC coupled light storage system, comprising:

[0039] a memory, configured to store a computer program;

[0040] a processor, configured to execute the computer program to implement the steps of the power control method of the three-phase AC coupled light storage system.

[0041] To solve the above technical problems, the application further provides a computer readable storage medium, wherein the computer readable storage medium stores a computer program, and the computer program is executed by a processor to implement the steps of the power control method of the three-phase AC coupled light storage system.

[0042] The power control method of the three-phase alternating coupling light storage system provided in the application synchronously collects three-phase power of a photovoltaic system, three-phase power of a power distribution cabinet and a power grid, and combines preset output power of an energy storage PCS to deduce three-phase load power, breaking the limitation of traditional systems that only collect total power or partial phase power; according to the size relationship between three-phase photovoltaic power and corresponding phase load power, different operation scenes are divided, dynamic adaptation of control strategies is realized through scene division, and the problem of limited power generation or low self-use rate caused by single control logic is avoided; when adjusting three-phase output power of the energy storage PCS, two core constraints are synchronously met, actual operation power of an N line ≤ maximum allowable power of the N line; absolute value of each phase output power of the energy storage PCS ≤ maximum power of single-phase AC / DC conversion, through N line power limitation and single-phase power limitation, stability of the power grid and the light storage system is ensured, disturbance of unbalanced current to the power grid is avoided, and the collaborative stability of the light storage system and the power grid is significantly improved.

[0043] In addition, the application also provides a device and a medium, which correspond to the power control method of the three-phase alternating coupling light storage system, and have the same effects. BRIEF DESCRIPTION OF DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the application, the drawings needed in the embodiments will be briefly introduced. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0045] Figure 1 A flow chart of the power control method of the three-phase alternating coupling light storage system provided in the embodiments of the application;

[0046] Figure 2 A schematic diagram of a typical alternating coupling light storage household system;

[0047] Figure 3 A structure diagram of the power control device of the three-phase alternating coupling light storage system provided in the embodiments of the application;

[0048] Figure 4 A structure diagram of another power control device of the three-phase alternating coupling light storage system provided in the embodiments of the application. DETAILED DESCRIPTION

[0049] With reference to the drawings and specific embodiments, the technical solutions in the embodiments of the present application will be described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0050] The core of the present application is to provide a power control method, device and medium of a three-phase alternating current coupling light storage system.

[0051] In order for those skilled in the art to better understand the present application, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0052] The present application provides a power control method of a three-phase alternating current coupling light storage system, the three-phase alternating current coupling light storage system comprising a photovoltaic system, an energy storage PCS, a battery and a load, the photovoltaic system being connected to an alternating current bus through an inverter, as shown in Figure 1 The method comprises the following steps:

[0053] S11: acquiring, through a current detection device of the energy storage PCS, A-phase photovoltaic power, B-phase photovoltaic power and C-phase photovoltaic power output by the photovoltaic system, and A-phase mutual interaction power, B-phase mutual interaction power and C-phase mutual interaction power exchanged with the power grid at the side of a power distribution cabinet;

[0054] S12: obtaining A-phase load power, B-phase load power and C-phase load power based on the A-phase photovoltaic power, B-phase photovoltaic power, C-phase photovoltaic power, A-phase mutual interaction power, B-phase mutual interaction power, C-phase mutual interaction power, and A-phase output power, B-phase output power and C-phase output power in the energy storage PCS;

[0055] S13: combining the maximum allowed power of the system N line and the maximum power of single-phase AC / DC conversion of the energy storage PCS, and dividing different operation scenarios according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power;

[0056] S14: adjusting the A-phase output power, B-phase output power and C-phase output power of the energy storage PCS for different scenarios; wherein the actual operation power of the N line is calculated through a two-phase stationary coordinate system conversion method to ensure that the actual operation power of the N line does not exceed the maximum allowed power of the N line, and the absolute value of the output power of each phase of the energy storage PCS does not exceed the maximum power of single-phase AC / DC conversion.

[0057] In order to balance the input and output, the energy storage PCS needs to make an unbalanced response to the load power and photovoltaic power of each phase, that is, the energy storage PCS realizes balanced input and output of the light storage system through unbalanced input and output.

[0058] Figure 2 A typical AC coupled light storage system is shown in FIG. 1, which includes a battery, a load, a photovoltaic system, and a storage PCS. The storage PCS samples the three-phase current of the photovoltaic inverter through a current detection device, and calculates the three-phase photovoltaic power A, B, and C as follows: Figure 2 Here, the reactive power generated by the photovoltaic is not considered, and the output power A, B, and C of the storage PCS are as follows: The maximum power of the single-phase AC / DC conversion of the storage PCS is defined as

[0059] The three-phase power A, B, and C exchanged between the distribution cabinet and the grid is as follows: which represents the power value exchanged between the light storage system and the three-phase grid. At the same time, the power flow direction of each unit of the light storage system to the AC bus is negative, and the power flow direction from the AC bus to each unit is positive.

[0060] The three-phase load power A, B, and C are obtained through the three-phase photovoltaic power A, B, and C, the three-phase power A, B, and C exchanged between the distribution cabinet and the grid, the output power A, B, and C of the storage PCS, and the first formula.

[0061] The first formula is as follows:

[0062] ;

[0063] wherein, A, B, and C are the three-phase load power A, B, and C, respectively. A, B, and C are the three-phase power A, B, and C exchanged between the distribution cabinet and the grid, respectively. A, B, and C are the output power A, B, and C of the storage PCS, respectively. A, B, and C are the three-phase photovoltaic power A, B, and C, respectively.

[0064] wherein, the three-phase power A, B, and C of the light storage system when the storage PCS is not adjusted are as follows:

[0065] ;

[0066] The grid connection mode of the three-phase storage PCS in the system is three-phase four-wire system, which is divided into three-phase lines and one N line. The role of the N line is to act as a drainage channel for unbalanced current when output imbalance occurs, to avoid three-phase voltage drift and N point drift.

[0067] ​​​In the three-phase inverter, the N line has limited current capacity due to device design limitations, cost considerations, and other factors. Here, the actual operating power of the N line is defined as , the maximum current capacity is , and the corresponding maximum current power is .

[0068] Since the energy storage PCS only outputs active power, when , the input and output power of the energy storage PCS is not limited by , when , the input and output power of the energy storage PCS is limited by when charging or discharging in phase sequence, and in addition, if the three-phase is charged or discharged at the same time, it will not be limited; since the energy storage PCS generally requires single-phase power to meet requirements, therefore cases are not considered.

[0069] The relationship between N line power limitation and three-phase power is usually calculated in two-phase stationary coordinates:

[0070] Specifically, it includes the A-phase output power, B-phase output power, and C-phase output power of the energy storage PCS, which are converted to two-phase power components in the two-phase stationary coordinates through αβ coordinate transformation.

[0071] The actual operating power of the N line is obtained through the two-phase power components.

[0072] The two-phase power components in the two-phase stationary coordinates include α-axis power components and β-axis power components.

[0073] Correspondingly, the actual operating power of the N line is obtained through the two-phase power components, including:

[0074] The actual operating power of the N line is obtained through the α-axis power components, β-axis power components, and the second formula.

[0075] The second formula is:

[0076] ;

[0077] where are the α-axis power components and β-axis power components, respectively; is the actual operating power of the N line.

[0078] The above-mentioned power is calculated by the MCU control unit of the energy storage PCS.

[0079] Based on the N-phase power limitation , a power control method for an AC-coupled light storage system is designed to improve the self-generation and self-use ratio and photovoltaic power generation capacity.

[0080] Step S13 combines The maximum power of the single-phase AC-DC conversion of the energy storage PCS is used to divide different operation scenarios according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power. It should be noted that the core basis of the scenario division is the power matching relationship between the photovoltaic and the load, that is, whether the photovoltaic can independently meet the load demand, whether the energy storage needs to be supplemented or absorbed. The purpose is to simplify the complex system state into a quantifiable scenario, and avoid the failure of a single strategy under diversified working conditions (such as the charging strategy when the photovoltaic is sufficient and the discharging strategy when the photovoltaic is insufficient need to be completely different).

[0081] Step S14 performs a power adjustment step, adjusts the A-phase, B-phase and C-phase output power of the energy storage PCS for different scenarios, and simultaneously calculates the actual operation power of the N line through two-phase stationary coordinate system conversion, to ensure that the actual operation power of the N line does not exceed the maximum allowable power of the N line, and the absolute value of the output power of each phase does not exceed the maximum power of the single-phase AC-DC conversion. It should be noted that the "two-phase stationary coordinate system conversion" is a specific method (not the only method, but this embodiment adopts this way) for calculating the N line power, and the core is to map the three-phase power into two-phase components through coordinate transformation, and then deduce the N line power. The adjustment process needs to simultaneously satisfy the N line constraint and the single-phase power constraint, and neither of them can be omitted. The purpose is to realize the photovoltaic priority utilization and the energy storage flexible compensation by dynamically adjusting the three-phase output of the energy storage PCS, to maximize the photovoltaic consumption and improve the self-generation and self-use ratio under the premise of ensuring the safety of the system (N line and PCS hardware limit).

[0082] The power control method of the three-phase AC coupled photovoltaic storage system provided in the application synchronously collects the three-phase power of the photovoltaic system, the three-phase power exchanged between the power distribution cabinet and the power grid through the current detection device of the energy storage PCS, and deduces the three-phase load power in combination with the preset output power of the energy storage PCS, thereby breaking through the limitation of the traditional system that only collects total power or partial phase power; different operation scenarios are divided according to the size relationship between the three-phase photovoltaic power and the corresponding phase load power, and the dynamic adaptation of the control strategy is realized through the scenario division, thereby avoiding the problem of limited power generation or low self-use ratio caused by a single control logic; when the three-phase output power of the energy storage PCS is adjusted, two core constraints are simultaneously satisfied, that is, the actual operation power of the N line ≤ the maximum allowable power of the N line, and the absolute value of the output power of each phase of the energy storage PCS ≤ the maximum power of the single-phase AC-DC conversion. Through the N line power limit and the single-phase power limit, the stability of the power grid and the photovoltaic storage system is ensured, the disturbance of the unbalanced current to the power grid is avoided, and the collaborative stability of the photovoltaic storage system and the power grid is significantly improved.

[0083] According to the above embodiments, in one specific embodiment, different operating scenarios include a first scenario: the photovoltaic power of phases A, B, and C are all greater than the load power of the corresponding phases; correspondingly, the output power of phase A, phase B, and phase C of the energy storage PCS are adjusted for different scenarios, including:

[0084] If the total power of the photovoltaic system minus the total power of the three-phase load does not exceed the charging limit power of the energy storage system, and the absolute value of the power of each phase of the system does not exceed the maximum power of the single-phase AC / DC conversion of the energy storage PCS when not adjusted, then phases A, B, and C of the energy storage PCS are all in the charging state, where the charging power of each phase = -(corresponding phase photovoltaic power) -(corresponding phase load power).

[0085] If the total power of the photovoltaic system minus the total power of the three-phase load exceeds the charging limit power of the energy storage system, or if the absolute value of the power of any phase of the system when not adjusted exceeds the maximum power of the single-phase AC / DC conversion of the energy storage PCS, then when the anti-reverse current function is activated, the total power of the photovoltaic system will be limited to within the charging limit power of the energy storage system through communication between the energy storage PCS and the photovoltaic system, and it will be ensured that the absolute value of the power of each phase does not exceed the maximum power of the single-phase AC / DC conversion of the energy storage PCS.

[0086] When there is sufficient sunlight during the day and the power of each of the three-phase photovoltaics exceeds the load power, the energy storage PCS will replenish the power according to the charging limit power of the energy storage system.

[0087] if Less than the charging power limit of the energy storage system, and All less than Then each phase of the energy storage PCS is in a charging state. Not considered a limiting factor, the charging power of the energy storage PCS is:

[0088] ;

[0089] if The power exceeds the charging limit of the energy storage system, or Any item greater than If reverse current protection is enabled, the energy storage PCS limits the photovoltaic power through the communication photovoltaic system's main control unit. Limited to below the charging power limit of the energy storage system, single-phase power limited to If reverse current protection is not enabled (i.e., surplus photovoltaic power is allowed to be fed into the grid), then there is no need to limit photovoltaic power. In this case, the energy storage PCS will only charge at its maximum capacity, and the remaining surplus power can be consumed by the grid. Whether to enable reverse current protection is determined by the user and the local grid standards.

[0090] According to the above embodiments, in a specific embodiment, different operating scenarios include a second scenario: one or two-phase photovoltaic power is less than the corresponding phase load power; accordingly, the A-phase output power, the B-phase output power, and the C-phase output power of the energy storage PCS are adjusted for different scenarios, including:

[0091] In the second scenario, if the anti-reverse flow function is turned on, the photovoltaic system output power exceeding the phase is first absorbed by the energy storage PCS, and then the remaining adjustable power is calculated based on the maximum allowable power of the system N line, and the load power gap of the insufficient phase is supplemented according to the remaining adjustable power;

[0092] If the anti-reverse flow function is not turned on, the load power gap of the insufficient phase is first supplemented by the energy storage PCS, and then the photovoltaic power exceeding the phase is absorbed based on the maximum allowable power of the system N line; wherein the exceeding phase refers to the phase whose photovoltaic power is greater than the corresponding phase load power, and the insufficient phase refers to the phase whose photovoltaic power is less than the corresponding phase load power.

[0093] When the daylight is not strong or the load power is large during the day, one or two-phase photovoltaic power is less than the load power, and the energy storage PCS supplements power according to the energy storage system charging power limit and the N-phase power limit.

[0094] Specifically, it is divided into the following two cases:

[0095] (1) One-phase photovoltaic power is greater than load power (i.e. two-phase photovoltaic power is less than the corresponding phase load power), assuming C phase (exceeding phase), and the remaining A and B phases (insufficient phase) photovoltaic power is less than the load power.

[0096] At this time, if the anti-reverse flow is turned on, the photovoltaic power of the exceeding phase is preferentially absorbed, and then the insufficient phase load power is supplemented, and here only the active power of the load is supplemented.

[0097] The power that the energy storage PCS needs to absorb in the C phase is calculated according to , that is, the C-phase output power of the energy storage PCS:

[0098] ;

[0099] The N-phase power margin is calculated according to the C-phase power (indicating that under the premise that the C-phase energy storage PCS output power is , the maximum allowable value of the sum of the absolute values of the adjustable power of A and B phases), if and , the power of , then according to the vector sum, the N-phase power will not exceed At this time, the total load gap of phase A and phase B does not exceed the maximum adjustment space of phase A and phase B, and after the gap of phase A and phase B is filled, the N line power is still within the safe range, so the load power of phase A and phase B can be fully filled.

[0100] If is less than , is greater than , at this time, the load power of phase B is filled first, because does not exceed the adjustment space, and after being filled, it will not cause the N line power to exceed the limit; after being filled, the load power of phase A is filled, at this time the remaining adjustment space is , and phase A can only fill the power in the remaining space (to avoid N line over-limit);

[0101] First, determine the output power of phase B ( preferentially meet the balance of phase B); then combine the output power of phase C , calculate the power of phase A by the formula .

[0102] If are all greater than , then the load gaps of phase A and phase B are filled in equal proportion, and are filled according to .

[0103] If the anti-backflow function is not turned on, the load power of phase A and phase B is filled first, and then the remaining N phase power is used to fill phase C.

[0104] Here, if there is a phase sequence power greater than (such as is greater than ), the output power of the corresponding phase ( ) is equal to to avoid device overload, and the other phase sequence is filled according to the difference between the load power and the photovoltaic power ( ).

[0105] If are all less than , at this time, the gaps of phase A and phase B can be completely filled, and then the C phase power is calculated based on the N line constraint, and the corresponding PCS power is:

[0106]

[0107] ; (C phase output power calculation formula under N line power constraint).

[0108] After phase A and phase B are completely filled, the maximum power that can be filled by phase C (charging) is calculated according to the remaining allowed power of the N line, to ensure that the N line power does not exceed the limit after three-phase adjustment.

[0109] (2), the two-phase photovoltaic power is greater than the load power (i.e. the one-phase photovoltaic power is less than the corresponding phase load power), assuming that the B and C phases (excess phases) and the A phase (deficiency phase) photovoltaic power is less than the load power. (The principle is the same as the above case, and the excess phase excess electricity is preferentially absorbed, and the deficiency phase gap is supplemented)

[0110] If the reverse current is started, the B and C phase photovoltaic power is preferentially absorbed, and the deficiency phase load power is supplemented:

[0111] ; (charging state);

[0112] ; (charging state);

[0113] ; (discharging state).

[0114] If the reverse current is not started, the A phase load power is preferentially supplemented, and the B and C phase photovoltaic power is absorbed.

[0115] Specifically, if is greater than , , (forced charging power limit, only partially supplement the gap), if is less than , (A phase gap is not over-limit), the calculated A phase supplemented load power is:

[0116] ;

[0117] According to the A phase power, the N phase power balance is calculated, if and The power is less than (A phase power is determined, and the total power that B and C phases can absorb is limited), so according to the vector sum, the N phase power will not exceed , and the B and C phase photovoltaic power can be fully absorbed.

[0118] If is less than , is greater than , at this time, the B phase remaining photovoltaic power is absorbed first, and the maximum absorption power of the C phase is calculated .

[0119] ;

[0120] (based on N line constraint, only absorb part of the excess electricity, and the remaining electricity is put on the grid).

[0121] If All greater than B, C phase according to absorbed. By compromise distribution of maximum absorption of excess power, not absorbed part of the online.

[0122] In summary, anti-reflux open: priority through absorb B, C phase of all excess power (to avoid reverse flow), and then use A phase gap in N line constraints, to ensure that the system is completely independent of the grid.

[0123] Anti-reflux is not open: priority through A phase gap (reduce grid dependence), and then according to the N line excess absorption B, C phase of excess power (improve self-generated self-use rate), over-limit part of the online, balance economic and safety.

[0124] Always single-phase power does not exceed (hardware protection), N line power does not exceed , formula derivation is based on these two constraints to ensure that the adjustment logic is rigorous and feasible.

[0125] According to the above embodiment, in a specific embodiment, different operating scenarios include a third scenario: the A phase, B phase and C phase photovoltaic power are all less than the corresponding phase load power; and correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted for different scenarios, including:

[0126] When the absolute value of the power of any phase of the system is less than the maximum single-phase AC / DC conversion power of the energy storage PCS, the gap between the load power and the photovoltaic power of each phase is supplemented by discharging; wherein the discharging power of each phase is determined according to the difference between the corresponding phase load power and the corresponding phase photovoltaic power, and the absolute value of the discharging power of each phase does not exceed the maximum single-phase AC / DC conversion power of the energy storage PCS.

[0127] If the three-phase load power is greater than the photovoltaic power, it means that the total photovoltaic power and the split-phase power are insufficient, and the energy storage PCS needs to discharge three-phase (output power to the AC bus) at the same time to make up for the difference between the photovoltaic and the load.

[0128] When All less than , the load gap of each phase can be completely supplemented by discharging the energy storage PCS, that is, the discharging power of each phase can reach the actual gap value; then the energy storage PCS is in a discharging state, not as a limiting item, the discharging power of the energy storage PCS is:

[0129] ;

[0130] The above formula embodies the linear relationship between the load gap and the energy storage discharge power, and power balance can be achieved through simple linear calculation. When the PCS discharges in three phases, the actual operating power of the N line will not exceed the maximum allowable power of the system N line.

[0131] In the above embodiment, the power control method of the three-phase alternating coupling light storage system is described in detail, and the application also provides an embodiment of a power control device of a three-phase alternating coupling light storage system. It should be noted that the embodiments of the device part are described from two angles, one is based on the functional module angle, and the other is based on the hardware angle.

[0132] Based on the functional module angle, Figure 3 The structure diagram of a power control device of a three-phase alternating coupling light storage system provided by an embodiment of the application is shown in Figure 3 The power control device of a three-phase alternating coupling light storage system, the three-phase alternating coupling light storage system includes a photovoltaic system, a storage PCS, a battery and a load, the photovoltaic system is connected to an alternating bus through an inverter, and includes:

[0133] The acquisition module 21 is configured to acquire the A-phase photovoltaic power, the B-phase photovoltaic power and the C-phase photovoltaic power output by the photovoltaic system, and the A-phase mutual interaction power, the B-phase mutual interaction power and the C-phase mutual interaction power exchanged with the power grid on the side of the power distribution cabinet through the current detection device of the storage PCS.

[0134] The calculation module 22 is configured to obtain the A-phase load power, the B-phase load power and the C-phase load power based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual interaction power, the B-phase mutual interaction power, the C-phase mutual interaction power, and the A-phase output power, the B-phase output power and the C-phase output power in the storage PCS.

[0135] The scene distinguishing module 23 is configured to combine the maximum allowable power of the system N line and the single-phase AC / DC conversion maximum power of the storage PCS, and divide different operating scenes according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power.

[0136] The adjustment module 24 is configured to adjust the A-phase output power, the B-phase output power and the C-phase output power of the storage PCS for different scenes respectively; wherein the actual operating power of the N line is calculated through a two-phase stationary coordinate system conversion method, so as to ensure that the actual operating power of the N line does not exceed the maximum allowable power of the N line, and the absolute value of each phase output power of the storage PCS does not exceed the single-phase AC / DC conversion maximum power.

[0137] Since the embodiments of the device part correspond to the embodiments of the method part, the embodiments of the device part are described in the description of the embodiments of the method part, which will not be described here.

[0138] Figure 4 Another structure diagram of the power control device of the three-phase alternating current coupling light storage system provided by the embodiment of the present application is shown in FIG. 3. The power control device of the three-phase alternating current coupling light storage system includes a memory 30 for storing a computer program. Figure 4

[0139] The processor 31 is configured to implement the steps of the method for obtaining the user operation habit information in the above embodiment (the power control method of the three-phase alternating current coupling light storage system) when executing the computer program.

[0140] The power control device of the three-phase alternating current coupling light storage system provided by the embodiment of the present application can include but is not limited to a mobile terminal, a personal computer, a workstation, etc.

[0141] The processor 31 can include one or more processing cores, such as a 4-core processor, an 8-core processor, etc. The processor 31 can be implemented in at least one of a hardware form of a Digital Signal Processor (DSP), a Field-Programmable Gate Array (FPGA), and a Programmable Logic Array (PLA). The processor 31 can also include a main processor and a coprocessor. The main processor is a processor for processing data in an awake state, also known as a Central Processing Unit (CPU). The coprocessor is a low-power processor for processing data in a standby state. In some embodiments, the processor 31 can be integrated with a Graphics Processing Unit (GPU). The GPU is responsible for rendering and drawing the content required to be displayed on the display screen. In some embodiments, the processor 31 can also include an Artificial Intelligence (AI) processor. The AI processor is used to process computing operations related to machine learning.

[0142] ​The memory 30 can include one or more computer-readable storage media. The memory 30 can also include high-speed random access memory and non-volatile, computer-readable storage media such as one or more magnetic disk storage devices, flash memory devices. In this embodiment, the memory 30 is used to store at least the following computer program 301, wherein the computer program is loaded and executed by the processor 31 and can implement the related steps of the power control method of the three-phase alternating current coupling light storage system disclosed in any of the preceding embodiments. In addition, the resources stored in the memory 30 can also include an operating system 302 and data 303, etc., and the storage mode can be temporary storage or permanent storage. The operating system 302 can include Windows, Unix, Linux, etc. The data 303 can include but is not limited to data related to the power control method of the three-phase alternating current coupling light storage system.

[0143] In some embodiments, the power control device of the three-phase alternating current coupling light storage system can also include a display screen 32, an input / output interface 33, a communication interface 34, a power supply 35 and a communication bus 36.

[0144] Those skilled in the art can understand that the structure shown in the above embodiments does not constitute a limitation on the power control device of the three-phase alternating current coupling light storage system, and can include more or fewer components than those shown in the drawings. Figure 4

[0145] The power control device of the three-phase alternating current coupling light storage system provided by the embodiments of the present application includes a memory and a processor, and the processor can implement the following method when executing the program stored in the memory: the power control method of the three-phase alternating current coupling light storage system.

[0146] Finally, the present application also provides an embodiment corresponding to a computer-readable storage medium. The computer-readable storage medium stores a computer program, and the computer program is executed by the processor to implement the steps as described in the power control method of the three-phase alternating current coupling light storage system.

[0147] ​It can be understood that if the method in the above embodiment is implemented in the form of a software function unit and sold or used as an independent product, it can be stored in a computer readable storage medium. Based on such understanding, the technical solutions of the present application essentially or the part of the prior art that contributes to the technical solutions or the whole or part of the technical solutions can be embodied in the form of a software product. The computer software product is stored in a storage medium, and performs all or part of the steps of the method described in each embodiment of the present application. The foregoing storage medium includes: a U disk, a mobile hard disk, a read-only memory (Read-Only Memory, ROM), a random access memory (Random Access Memory, RAM), a magnetic disk or an optical disk, and various media that can store program codes.

[0148] The computer readable storage medium provided by the embodiment stores a computer program, and when a processor executes the program, the following method can be implemented: a power control method of a three-phase alternating current coupled light storage system.

[0149] The three-phase alternating current coupled light storage system power control method, device and medium provided by the present application are described in detail above. The embodiments in the specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts of each embodiment can be referred to. For the device disclosed in the embodiments, since it corresponds to the method disclosed in the embodiments, it is described simply, and the related parts are described in the method part. It should be pointed out that for ordinary skilled in the art, without departing from the principles of the present application, some improvements and modifications can be made to the present application, and these improvements and modifications also fall within the protection scope of the claims of the present application.

[0150] It should also be noted that in the present specification, relationship terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between the entities or operations. Moreover, the terms "include", "contain" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements not only includes those elements, but also includes other elements not explicitly listed or inherent to such process, method, article or device. Without more limitations, the element defined by the statement "including a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

Claims

1. A method for power control of a three-phase alternating current (AC) coupled optical storage system, the method comprising: The three-phase alternating current coupling light storage system comprises a photovoltaic system, a storage PCS, a battery and a load, the photovoltaic system is connected to an alternating current bus through an inverter, and the method comprises the following steps: A-phase photovoltaic power, B-phase photovoltaic power and C-phase photovoltaic power output by the photovoltaic system are collected respectively through a current detection device of the storage PCS, and A-phase mutual interaction power, B-phase mutual interaction power and C-phase mutual interaction power interacting with the power grid on the side of a power distribution cabinet are collected; A-phase load power, B-phase load power and C-phase load power are obtained based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual interaction power, the B-phase mutual interaction power, the C-phase mutual interaction power and A-phase output power, B-phase output power and C-phase output power in the storage PCS; Different operation scenarios are divided according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power in combination with the maximum allowable power of the system N line and the maximum power of single-phase AC / DC conversion of the storage PCS; A-phase output power, B-phase output power and C-phase output power of the storage PCS are adjusted respectively for different scenarios; wherein the actual operation power of the N line is calculated through a two-phase static coordinate system conversion method, so as to ensure that the actual operation power of the N line does not exceed the maximum allowable power of the N line, and the absolute value of the output power of each phase of the storage PCS does not exceed the maximum power of single-phase AC / DC conversion; wherein the actual operation power of the N line is calculated through a two-phase static coordinate system conversion method, comprising: Two-phase power components in a two-phase static coordinate system are obtained through αβ coordinate transformation based on the A-phase output power, the B-phase output power and the C-phase output power of the storage PCS; The actual operation power of the N line is obtained through the two-phase power components; The two-phase power components in the two-phase static coordinate system comprise an α-axis power component and a β-axis power component; Correspondingly, the actual operation power of the N line is obtained through the two-phase power components, comprising: The actual operation power of the N line is obtained through the α-axis power component, the β-axis power component and a second formula; The second formula is: ； wherein, are the α-axis power component and the β-axis power component, respectively; is the actual operating power of the N lines, are the A-phase output power, the B-phase output power, and the C-phase output power in the energy storage PCS, respectively.

2. The method of claim 1, wherein the three-phase AC coupled optical storage system is a system comprising: A-phase load power, B-phase load power and C-phase load power are obtained based on the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual interaction power, the B-phase mutual interaction power, the C-phase mutual interaction power and A-phase output power, B-phase output power and C-phase output power in the storage PCS, comprising: A-phase, B-phase and C-phase load power are obtained through the A-phase photovoltaic power, the B-phase photovoltaic power, the C-phase photovoltaic power, the A-phase mutual interaction power, the B-phase mutual interaction power, the C-phase mutual interaction power, the A-phase output power, the B-phase output power and the C-phase output power in the storage PCS and a first formula; The first formula is: ； wherein, respectively, are A, B, C three-phase load power; respectively, are the A-phase mutual power, the B-phase mutual power, and the C-phase mutual power; respectively, are A-phase output power, B-phase output power, and C-phase output power in the energy storage PCS; respectively, are the A-phase photovoltaic power, the B-phase photovoltaic power, and the C-phase photovoltaic power.

3. The method of claim 1, wherein the three-phase AC coupled optical storage system is a system comprising: The different operation scenarios comprise a first scenario: the A-phase, B-phase and C-phase photovoltaic power are all greater than the corresponding phase load power; correspondingly, A-phase output power, B-phase output power and C-phase output power of the storage PCS are adjusted respectively for different scenarios, comprising: If the total power of the photovoltaic system minus the total power of the three-phase load does not exceed the charging limit power of the energy storage system, and the absolute value of the power of each phase of the system without adjustment does not exceed the maximum power of single-phase AC-DC conversion of the energy storage PCS, the A phase, the B phase and the C phase of the energy storage PCS are in the charging state, wherein the charging power of each phase is equal to - (the corresponding phase photovoltaic power) - (the corresponding phase load power); If the total power of the photovoltaic system minus the total power of the three-phase load exceeds the charging limit power of the energy storage system, or the absolute value of the power of any phase of the system without adjustment exceeds the maximum power of single-phase AC-DC conversion of the energy storage PCS, when the anti-reverse flow function is turned on, the total power of the photovoltaic system is limited to the charging limit power of the energy storage system through the communication between the energy storage PCS and the photovoltaic system, and the absolute value of the power of each phase is ensured to be less than the maximum power of single-phase AC-DC conversion of the energy storage PCS.

4. The method of claim 3, wherein the method further comprises: The different operation scenarios include a second scenario: one or two-phase photovoltaic power is less than the corresponding phase load power; correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted respectively for different scenarios, including: In the second scenario, if the anti-reverse flow function is turned on, the excess phase output power of the photovoltaic system is first absorbed by the energy storage PCS, and then the remaining adjustable power is calculated based on the maximum allowed power of the system N line, and the load power gap of the insufficient phase is supplemented according to the remaining adjustable power; If the anti-reverse flow function is not turned on, the load power gap of the insufficient phase is first supplemented by the energy storage PCS, and then the excess phase photovoltaic power is absorbed based on the maximum allowed power of the system N line; wherein the excess phase refers to the phase in which the photovoltaic power is greater than the corresponding phase load power, and the insufficient phase refers to the phase in which the photovoltaic power is less than the corresponding phase load power.

5. The method of claim 1, wherein, The different operation scenarios include a third scenario: the A phase, the B phase and the C phase photovoltaic power are all less than the corresponding phase load power; correspondingly, the A phase output power, the B phase output power and the C phase output power of the energy storage PCS are adjusted respectively for different scenarios, including: When the absolute value of the power of any phase of the system without adjustment is less than the maximum power of single-phase AC-DC conversion of the energy storage PCS, the discharge is used to supplement the gap between the load power and the photovoltaic power of each phase; wherein the discharge power of each phase is determined according to the difference between the corresponding phase load power and the corresponding phase photovoltaic power, and the absolute value of the discharge power of each phase is less than the maximum power of single-phase AC-DC conversion of the energy storage PCS.

6. A power control device for a three-phase AC coupled optical storage system, characterized by The three-phase AC-coupled photovoltaic energy storage system includes a photovoltaic system, an energy storage PCS, a battery and a load, the photovoltaic system is connected to an AC bus through an inverter, and includes: A collection module is configured to collect A phase photovoltaic power, B phase photovoltaic power and C phase photovoltaic power output by the photovoltaic system through a current detection device of the energy storage PCS, and collect A phase mutual interaction power, B phase mutual interaction power and C phase mutual interaction power exchanged with the power grid on the side of a power distribution cabinet; A calculation module is configured to obtain A phase load power, B phase load power and C phase load power based on the A phase photovoltaic power, the B phase photovoltaic power, the C phase photovoltaic power, the A phase mutual interaction power, the B phase mutual interaction power, the C phase mutual interaction power, and A phase output power, B phase output power and C phase output power in the energy storage PCS. The scene distinguishing module is used to combine the maximum allowed power of the system N line and the maximum power of the single-phase AC / DC conversion of the energy storage PCS, and divide different operation scenes according to the size relationship between the A-phase, B-phase and C-phase photovoltaic power and the corresponding phase load power. The adjusting module is used to adjust the A-phase output power, B-phase output power and C-phase output power of the energy storage PCS for different scenes respectively; wherein the actual operation power of the N line is calculated by the two-phase stationary coordinate system conversion method, so as to ensure that the actual operation power of the N line does not exceed the maximum allowed power of the N line, and the absolute value of the output power of each phase of the energy storage PCS does not exceed the maximum power of the single-phase AC / DC conversion thereof. The actual operation power of the N line is calculated by the two-phase stationary coordinate system conversion method, including: Based on the A-phase output power, B-phase output power and C-phase output power of the energy storage PCS, two-phase power components in the two-phase stationary coordinate system are obtained by αβ coordinate transformation; The actual operation power of the N line is obtained by the two-phase power components; The two-phase power components in the two-phase stationary coordinate system include α-axis power components and β-axis power components; Correspondingly, the actual operation power of the N line is obtained by the two-phase power components, including: The actual operation power of the N line is obtained by the α-axis power components, β-axis power components and a second formula; The second formula is: ； wherein, are the α-axis power component and the β-axis power component, respectively; is the actual operating power of the N line, are the A-phase output power, the B-phase output power, and the C-phase output power in the energy storage PCS, respectively.

7. A power control device for a three-phase AC coupled optical storage system, characterized by, including: The memory is used to store the computer program; The processor is used to execute the computer program to realize the steps of the power control method of the three-phase AC coupled photovoltaic storage system according to any one of claims 1 to 5.

8. A computer-readable storage medium, characterized in that, The computer program is stored on the computer readable storage medium, and the computer program is executed by the processor to realize the steps of the power control method of the three-phase AC coupled photovoltaic storage system according to any one of claims 1 to 5.

Images