WO2023077840A1

WO2023077840A1 - Photovoltaic system in which assembly-level optimizer is installed in targeted manner, and power optimization method therefor

Info

Publication number: WO2023077840A1
Application number: PCT/CN2022/102839
Authority: WO
Inventors: 彭文博; 高虎; 肖平; 赵东明; 李晓磊; 虞祥瑞; 朱文哲; 罗丽珍
Original assignee: 中国华能集团清洁能源技术研究院有限公司; 华能集团技术创新中心有限公司
Priority date: 2021-11-03
Filing date: 2022-06-30
Publication date: 2023-05-11
Also published as: CN114421883A

Abstract

Provided in the present application are a photovoltaic system in which an assembly-level optimizer is installed in a targeted manner, and a power optimization method therefor. The method comprises: selecting an abnormal assembly according to a preset installation ratio of assembly MPPT controllers or according to an actual measurement result, and determining a target assembly from a photovoltaic system; and installing an assembly MPPT controller for the target assembly. For the entire photovoltaic system, assembly MPPT controllers are only installed for some assemblies according to an installation ratio, such that the power generation increment is improved, and the installation cost and invalid energy loss of the assembly MPPT controllers of the photovoltaic system are also greatly reduced, thereby effectively improving the economic benefits. The number of hardware installations is effectively reduced, and the investment of time and cost is reduced; and fewer fault points and less standby power consumption can be achieved by reducing the number of hardware installations.

Description

A photovoltaic system with targeted installation of component-level optimizer and its power optimization method

This application claims the priority of the Chinese patent application submitted to the China Patent Office on November 3, 2021 with the application number 202111295108.4 and the title of the invention "a photovoltaic system with a spot-mounted module-level optimizer and its installation method", all of which The contents are incorporated by reference in this application.

technical field

The present application relates to the field of photovoltaic systems, and in particular to a photovoltaic system with targeted installation of component-level optimizers and a power optimization method thereof.

Background technique

The construction of photovoltaic power plants is easily restricted by environmental conditions, which makes it easy to produce shadows when the battery modules are working. The centralized inverter method is adopted in the photovoltaic power station. The MPPT (Maximum Power Point Tracking) adjustment of the inverter cannot ensure that each battery module is in an ideal condition, and cannot output the maximum power, resulting in partial power loss. In view of this problem, the method of installing the component MPPT controller is used to solve it. At present, the installation method of module MPPT controller is to install all the photovoltaic modules of the photovoltaic system. Although the power consumption can be tapped, the installation cost is high. At the same time, with the increase of hardware, the number of failure points increases. In addition, for photovoltaic systems with abnormal components, the control self-loss after installing the MPPT controller of all components offsets the power increase obtained by reducing the abnormal loss of the photovoltaic system.

Contents of the invention

In view of the above problems, the present application provides a photovoltaic system and a power optimization method for the targeted installation module MPPT controller. The technical scheme of the application is as follows:

According to the first aspect of the embodiment of the present application, there is provided a photovoltaic system power optimization method targeting the installation component MPPT controller, including:

According to the installation ratio of the preset component MPPT controller, or select abnormal components according to the measured results, the target components are determined from the photovoltaic system.

Install the component MPPT controller on the target component.

In some embodiments of the present application, the preset installation ratio of the component MPPT controller includes:

Based on the power generation increment after installing the component MPPT controller and the cost of installing the component MPPT controller, determine the installation ratio of the component MPPT controller.

In some embodiments of the present application, the installation of the component MPPT controller on the target component includes:

One component MPPT controller is installed for each target component, or one component MPPT controller is installed for multiple target components, or multiple component MPPT controllers are installed for each target component whose power exceeds a preset range.

In some embodiments of the present application, as shown in FIG. 3, the determination of the target component from the photovoltaic system includes:

The components in the photovoltaic system are patrolled, and abnormal components are locked, and the target components include abnormal components that meet the fault type requirements among the abnormal components.

In some embodiments of the present application, the determining the target component from the photovoltaic system further includes:

Acquiring quantity information of the abnormal component;

If the quantity information is smaller than the installation ratio, it is predicted that there will be a forecast component set that will be shaded with seasonal changes or environmental changes; the target component includes the abnormal component and the forecast component set.

In some embodiments of the present application, the patrolling of components in the photovoltaic system and locking of abnormal components include:

The components in the photovoltaic system are inspected by the drone inspection system, and abnormal components are locked; wherein, the abnormal components include components that generate hot spots and components that are damaged in appearance.

For the photovoltaic system, component IV detection, group string IV detection and EL detection are performed to lock abnormal components, and the abnormal components include components with power attenuation.

In some embodiments of the present application, the inspection of the components in the photovoltaic system, before locking the abnormal components, also includes:

For the photovoltaic system, through the analysis of power generation and PR value, it is judged whether there is power loss in the photovoltaic system;

If there is power loss, it is determined that there are abnormal components in the photovoltaic system.

In some embodiments of the present application, the method also includes:

Obtaining the first power of the group string to which the abnormal component belongs after the component MPPT controller is installed, and comparing the first power with the second power in the normal period when the components of the group string to which the component belongs are not abnormal;

If the comparison result satisfies the preset condition, the component MPPT controller on the abnormal component has been installed;

If the comparison result does not meet the preset condition, further analyze the fault point of the abnormal component, and perform corresponding processing until the fault point of the abnormal component is resolved, and remove the component MPPT controller connected to the abnormal component.

According to the second aspect of the embodiment of the present application, there is provided a photovoltaic system with targeted installation of a component-level optimizer, the photovoltaic system includes a plurality of components, and the plurality of components adopts the method described in the first aspect to realize component MPPT control The power optimization of the device.

The photovoltaic system and its power optimization method provided by the embodiments of the present application target the installation of component-level optimizers. For the entire photovoltaic system, according to the installation ratio, only some components are installed with component MPPT controllers, which greatly improves the power generation increment while greatly Reduce the installation cost and invalid energy loss of the MPPT controller of the photovoltaic system components, and effectively improve the economic benefits. Effectively reduce the number of hardware installations, reduce time and cost investment, and reduce the number of hardware installations can bring fewer failure points and less standby power consumption.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the application.

Description of drawings

The accompanying drawings here are incorporated into the specification and constitute a part of the specification, show the embodiment consistent with the application, and are used together with the specification to explain the principle of the application, and do not constitute an improper limitation of the application.

Fig. 1 is a flow chart of a method for installing an MPPT controller of a targeted installation component according to an embodiment of the present application.

Fig. 2 is a structural diagram of a photovoltaic system according to an embodiment of the present application.

Fig. 3 is a schematic flowchart of a method for determining a target component according to an embodiment of the present application.

Detailed ways

In order to enable ordinary persons in the art to better understand the technical solutions of the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the accompanying drawings.

It should be noted that the terms "first" and "second" in this application are used to distinguish similar objects, but not necessarily used to describe a specific sequence or sequence. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein. The implementations described in the following exemplary embodiments do not represent all implementations consistent with this application. Rather, they are merely examples of apparatuses and methods consistent with aspects of the present application as recited in the appended claims.

Explanation of terms in this application:

The full name of MPPT (Maximum Power Point Tracking) controller is "Maximum Power Point Tracking" solar controller.

PR (Performance Ratio) value: It is an internationally used photovoltaic system quality evaluation index, which refers to the ratio of the actual power generation to the expected power generation, and is dimensionless.

The construction of photovoltaic power plants is easily restricted by environmental conditions, which makes it easy to produce shadows when the battery modules are working. For example, the spacing between photovoltaic arrays is not large enough, and the front row of photovoltaic modules (referred to as modules) will block the rear row of photovoltaic modules during sunrise and sunset; there are mountains or buildings near the power station to form shadows; cloudy weather, part of the photovoltaic array is blocked by dark clouds.

The centralized inverter method is adopted in the photovoltaic power station. The MPPT adjustment of the inverter cannot ensure that each battery module is in an ideal condition, and cannot output the maximum power, resulting in partial power loss.

The component MPPT controller (power optimizer or component-level optimizer) has a buck-boost circuit and a sensor inside, which samples the output voltage and current of the panel in real time, controls the buck-boost circuit through an advanced MPPT algorithm, and keeps the panel working at In the state of maximum power, the output matches the relationship between the voltage and current of the string to maximize the power generation.

The higher the output voltage, the smaller the output current; the higher the output current, the lower the output voltage. Only when the voltage and current have an ideal matching relationship can the battery pack output maximum power. When the irradiance decreases, the maximum power current becomes lower, and the maximum power point shifts to low voltage.

The component MPPT controller realizes that when the component current is not large enough and is short-circuited by the string, the component MPPT controller performs a step-down conversion to output a larger current; The voltage at the output terminal of the controller remains high, the current matches the string current, and the voltage at the input terminal of the module drops to the MPPT position, thereby outputting the maximum power.

The current installation method of module MPPT controller is to install module MPPT controller for all photovoltaic modules of the photovoltaic system, and this installation method is defined as full installation. The disadvantages of the full-load method are: the cost of the component MPPT controller is high, and the cost of comprehensive installation investment is high; for power loss, the income brought by the increase in power generation of the fully installed component MPPT controller is not necessarily high; the component MPPT controller is for Components that need to be "optimized" (such as shadow occlusion, or serious component attenuation, etc.) are meaningful, and have a higher meaning after installation, but for components that do not have shadow occlusion or severe attenuation, not only do not have the effect of optimization, but Additional standby power consumption is increased, and the complexity of the entire photovoltaic system is also increased, thereby increasing the hidden danger of failure.

Therefore, in response to this problem, this application proposes a more scientific photovoltaic system and installation strategy for module MPPT controllers, that is, to install module MPPT controllers for some modules, that is, targeted installation.

Fig. 1 is a flow chart of a method for installing an MPPT controller of a targeted installation component according to an embodiment of the present application. As shown in Fig. 1, the method may include the following steps.

S101. Determine the target component from the photovoltaic system according to the preset installation ratio of the component MPPT controller;

When setting the installation ratio, many factors need to be considered, such as the power generation increment after installing the component MPPT controller, the cost of installing the component MPPT controller, output power, and loss of the photovoltaic system, etc. The considerations are not limited to this. The installation ratio is different, the power generation increment after installing the MPPT controller of the photovoltaic system is different, and the cost of installing the MPPT controller of the module is different.

In this embodiment, optionally, the installation ratio of the component MPPT controller is determined based on the power generation increment after the component MPPT controller is installed and the cost of installing the component MPPT controller.

There may be many screening conditions for determining target components to be installed with component MPPT controllers from the photovoltaic system, such as abnormal components, components prone to shading, evenly distributed components, and the like.

S102. Install a component MPPT controller on the target component.

One component MPPT controller is installed for each target component, or one component MPPT controller is installed for multiple target components, or multiple component MPPT controllers are installed for each target component whose power exceeds a preset range. For example, two component MPPT controllers are installed for each target component with relatively large power.

The installation method of the target installation module MPPT controller of the embodiment of the present application is aimed at the entire photovoltaic system, according to the installation ratio, only installs the module MPPT controller on some modules, and greatly reduces the module MPPT of the photovoltaic system while increasing the power generation increment. Controller installation cost and invalid energy loss effectively improve economic benefits. Effectively reduce the number of hardware installations, reduce time and cost investment, and reduce the number of hardware installations can bring fewer failure points and less standby power consumption.

In some embodiments, the method of determining a target component from a photovoltaic system includes:

The output power of abnormal components is damaged, and it is necessary to install the component MPPT controller for optimization.

It can be understood that if there are many abnormal components detected, that is, exceeding the installation ratio, all abnormal components need to be installed.

In general, the number of abnormal components is far less than the installation ratio, for example, only 1% of abnormal components. At this time, you can install according to the preset installation ratio, and the installation point covers all abnormal components. For the selection of the installation point of the component that is not yet abnormal, various angles can be considered. For example, when determining target components, components that are prone to occlusion can be considered for installation, or randomly selected, or which components are more prone to abnormalities can be predicted. For example, for the selection of installation points of components that are not yet abnormal, predict which photovoltaic components are most prone to shading, defects, etc. Some photovoltaic modules are not shaded in summer, but may be shaded in winter, and some locations are prone to grass, trees and other factors, which can be judged and predicted on the spot. It can also be judged based on historical data which components are prone to aging and damage.

Wherein, for the forecasted component set, the MPPT controller of the installation component can be dynamically installed, for example, the MPPT controller of the component is regularly installed and removed according to time changes, so as to realize dynamic changes.

In some embodiments, optionally, the method for determining a target component from a photovoltaic system further includes:

Acquiring quantity information of the abnormal component;

After installing the component MPPT controller for components that are not yet abnormal, if there is a defect later, it will also play an optimization role.

It should be noted that there are many ways to check the components in the photovoltaic system and lock the abnormal components. The inspection methods are different, and the abnormal components may be different. The abnormal components are the fault points.

In an implementation manner, the inspection of components in the photovoltaic system and locking of abnormal components include:

In yet another implementation manner, for the photovoltaic system, component IV detection, group string IV detection, and EL detection are performed to lock abnormal components, and the abnormal components include components with power attenuation.

It should be noted that there are many types of exceptions (ie, fault types) of the exception component, and different processing strategies may be adopted for different types of exceptions.

Because there are many fault factors of the abnormal component, the cause of the fault cannot be found at one time, and invisible faults are difficult to detect and deal with. The method of setting remote fault diagnosis can be adopted. The cause of the failure may include A) power failure of the array, B) low input power of the array, C) low efficiency of the inverter, D) damage to the inverter, E) failure of the circuit breaker, and F) damage to the data collector.

For different fault types, the target component includes an abnormal component that meets the requirements of the fault type among the abnormal components, that is, the MPPT controller is not installed for all abnormal components of the fault type. For example, if the abnormal component is a component with damaged appearance, the abnormal component is directly short-circuited and the fault is handled immediately. If the appearance is obviously damaged, which endangers the safe operation of the string or even the station area, you can directly short-circuit the abnormal components. If the abnormal component has no abnormal appearance, directly install the MPPT controller of the component, and quickly repair the group string temporarily. For example, if there are bird droppings or sticky leaves on the modules, such shelters will cause hot spots, but they will not endanger the safety of the strings, and the on-site treatment will be more troublesome. Generally, the operation and maintenance of photovoltaic power plants will not deal with them. , and will not even make a record, waiting for the component to be cleaned or the rain to clean up the abnormal points. However, photovoltaic power plants are generally located in areas with little rain, and the frequency of rain is not high, and the frequency of module cleaning is even lower. In this way, the period of the abnormal state will be relatively long, and the power of the string will be continuously reduced, which will affect the power generation for a long time. This kind of components with no appearance damage and abnormal appearance can be directly installed with MPPT controllers, which can quickly improve the power drop caused by hot spots and other problems, and increase the power generation of the strings. After the components are cleaned, the drone inspection finds that the components return to normal, and the MPPT controller can be removed.

For example, the attenuation of the modules is greater than expected, and the solution of targeting the installation of MPPT controllers for modules can improve the power of the strings and maintain a consistently high power generation of the strings. If the abnormal component continues to decay rapidly, to a level that requires replacement. The replacement cycle of modules is generally relatively long, especially in the middle and late stages of photovoltaic power plant operation, spare modules of the same type have been used up, the iteration speed of module products on the market is fast, and the matching degree of modules that can be purchased normally is relatively low , then the procurement and replacement cycle will become longer. During this period, the targeted installation component MPPT controller can continue to maintain the string at a higher power level.

On the basis of the above embodiments, the inspection of the components in the photovoltaic system, before locking the abnormal components, also includes:

For the photovoltaic system, through power generation analysis and PR value analysis, it is judged whether there is power loss in the photovoltaic system; if there is power loss, it is judged that there are abnormal components in the photovoltaic system.

The embodiment of the present application conducts a preliminary evaluation of the photovoltaic system, analyzes the power loss of the photovoltaic system, influencing factors, etc., and judges whether there are abnormal components in the photovoltaic system, that is, whether it is necessary to install an MPPT controller for the abnormal components.

On the basis of the above-mentioned embodiments, optionally, the installation method of the targeted installation component MPPT controller may also include:

For example, analyze the comparison between the power of the string after MPPT installation and the normal period of the string, if it reaches more than 98% of the normal period, MPPT will continue to be installed and the maintenance will be completed. If it cannot reach 98% of the normal period, MPPT is used as a means to temporarily increase the power of the string. Further analyze the fault point of the abnormal component. If there is no potential safety hazard, MPPT can be used as a temporary solution. After the fault point is completely resolved, the MPPT can be removed. Generally, the cycle of module replacement is relatively long. During the cycle before replacement, MPPT can be used as an effective temporary solution to effectively improve the power of abnormal strings by more than 3.2%.

The installation method of the target installation module MPPT controller of the embodiment of the present application is aimed at the entire photovoltaic system, according to the installation ratio, only installs the module MPPT controller on some modules, and greatly reduces the module MPPT of the photovoltaic system while increasing the power generation increment. Controller installation cost and invalid energy loss effectively improve economic benefits. Effectively reduce the number of hardware installations, reduce time and cost investment, and reduce the number of hardware installations can bring fewer failure points and less standby power consumption. Further, it can accurately judge the abnormal components of the photovoltaic power station to achieve the best optimization effect. For a photovoltaic module that is not installed with a module MPPT controller, after the module fails, the module MPPT controller installed on other photovoltaic modules will also play an optimization role to reduce the loss caused by the mismatch of the photovoltaic system.

Fig. 2 is a structural diagram of a photovoltaic system targeted to install a component-level optimizer according to an embodiment of the present application. As shown in FIG. 2 , the photovoltaic system includes a plurality of components, and the above-mentioned installation method of targeting the MPPT controller of the component is used to realize the installation of the MPPT controller of the component.

The photovoltaic system that targets the installation of component-level optimizers proposed in the embodiment of this application is aimed at the entire photovoltaic system. According to the installation ratio, only some components are installed with component MPPT controllers, which greatly reduces the component MPPT of the photovoltaic system while increasing the power generation increment. Controller installation cost and invalid energy loss effectively improve economic benefits. Effectively reduce the number of hardware installations, reduce time and cost investment, and reduce the number of hardware installations can bring fewer failure points and less standby power consumption. Further, it can accurately judge the abnormal components of the photovoltaic power station to achieve the best optimization effect. For a photovoltaic module that is not installed with a module MPPT controller, after the module fails, the module MPPT controller installed on other photovoltaic modules will also play an optimization role to reduce the loss caused by the mismatch of the photovoltaic system.

Other embodiments of the present application will be readily apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any modification, use or adaptation of the application, these modifications, uses or adaptations follow the general principles of the application and include common knowledge or conventional technical means in the technical field not disclosed in the application . The specification and examples are to be considered as illustrative only.

It should be understood that the present application is not limited to the precise constructions which have been described above and shown in the accompanying drawings, and various modifications and changes may be made without departing from the scope thereof. The scope of the application is limited only by the appended claims.

Claims

A photovoltaic system power optimization method targeting the installation of a component-level optimizer, characterized in that it includes:

Determine the target components from the photovoltaic system according to the installation ratio of the preset component MPPT controller, or select abnormal components according to the actual measurement results;

Install the component MPPT controller on the target component.
The method according to claim 1, wherein the preset installation ratio of the component MPPT controller comprises:

Based on the power generation increment after installing the component MPPT controller and the cost of installing the component MPPT controller, the installation ratio of the component MPPT controller is determined.
The method according to claim 1, wherein said installing a component MPPT controller on said target component comprises:

One component MPPT controller is installed for each target component, or one component MPPT controller is installed for multiple target components, or multiple component MPPT controllers are installed for each target component whose power exceeds a preset range.
The method according to claim 1, wherein said determining the target component from the photovoltaic system comprises:

The components in the photovoltaic system are patrolled, and abnormal components are locked, and the target components include abnormal components that meet the fault type requirements among the abnormal components.
The method according to claim 4, wherein said determining the target component from the photovoltaic system further comprises:

Acquiring quantity information of the abnormal component;

If the quantity information is smaller than the installation ratio, it is predicted that there will be a forecast component set that will be shaded with seasonal changes or environmental changes; the target component includes the abnormal component and the forecast component set.
The method according to claim 4, wherein the inspection of components in the photovoltaic system to lock abnormal components includes:

The components in the photovoltaic system are inspected by the drone inspection system, and abnormal components are locked; wherein, the abnormal components include components that generate hot spots and components that are damaged in appearance.
The method according to claim 6, wherein the inspection of components in the photovoltaic system to lock abnormal components includes:

For the photovoltaic system, component IV detection, group string IV detection and EL detection are performed to lock abnormal components, and the abnormal components include components with power attenuation.
The method according to claim 4, wherein the inspection of the components in the photovoltaic system, before locking the abnormal components, further includes:

For the photovoltaic system, through the analysis of power generation and PR value, it is judged whether there is power loss in the photovoltaic system;

If there is power loss, it is determined that there are abnormal components in the photovoltaic system.
The method according to claim 4, characterized in that the method further comprises:

Obtaining the first power of the group string to which the abnormal component belongs after the component MPPT controller is installed, and comparing the first power with the second power in the normal period when the components of the group string to which the component belongs are not abnormal;

If the comparison result satisfies the preset condition, the component MPPT controller on the abnormal component has been installed;

If the comparison result does not meet the preset condition, further analyze the fault point of the abnormal component, and perform corresponding processing until the fault point of the abnormal component is resolved, and remove the component MPPT controller connected to the abnormal component.
A photovoltaic system for targeted installation of a component-level optimizer, characterized in that the photovoltaic system includes a plurality of components, and the plurality of components adopts the method described in any one of claims 1 to 9 to implement a component MPPT controller installation.