WO2021031933A1

WO2021031933A1 - Photovoltaic power generation system

Info

Publication number: WO2021031933A1
Application number: PCT/CN2020/108444
Authority: WO
Inventors: 周建军; 曹世磊; 汪林蔚; 石峰; 刘睿泽; 王强; 胡小玲; 胡艳; 严丹; 唐承容; 周娟
Original assignee: 西藏富鼎实业有限公司
Priority date: 2019-08-19
Filing date: 2020-08-11
Publication date: 2021-02-25
Also published as: CN110365060A

Abstract

A photovoltaic power generation system, which is mainly applied to the technical field of photovoltaic power generation, specifically comprising at least one photovoltaic power generation sub-system, each photovoltaic power generation sub-system comprises at least one photovoltaic power generation assembly, at least one voltage stabilizing component and a boosting component, the voltage stabilizing component enables each photovoltaic assembly to output a predetermined voltage value, the voltage stabilizing components with the same output voltage value are connected in parallel, and connected in parallel to the boosting component, the output voltage value of the boosting component is set according to the requirements of a convergence box for the voltage of photovoltaic strings, and finally, the boosting components with the same output voltage value are connected to the convergence box, this non-series independent power generation convergence technology ensures that each photovoltaic assembly and each group of power generation sub-systems can be converged at the same voltage, so as to maximize the power output efficiency of photovoltaic panels, improve photovoltaic power generation efficiency, increase economic income of a photovoltaic power station, and realize rapid cost recovery of the photovoltaic power station.

Description

A photovoltaic power generation system

Technical field

The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation system.

Background technique

Photovoltaic power generation technology has had a long-term development, and photovoltaic power generation projects have been widely used. The 18% photovoltaic conversion rate is a huge technical bottleneck for photovoltaic power generation, and the overall conversion rate of light energy is too poor. On the basis of not changing any original photovoltaic power generation media (including silicon, PN board, cast light glass glue, etc.), improving the photovoltaic forwarding rate and the overall power generation of solar energy is the current research direction in the field of photovoltaic power generation. The core technology is how to transfer the light energy-obtained electrons to the charging end quickly without being consumed, and then forward the electrical energy converted from light energy to the outside.

In electronic technology, there are two ways to flow electrons in series and parallel. The traditional photovoltaic power generation system connects multiple photovoltaic modules with the same photoelectric characteristics in series, and multiple groups are connected in series through the photovoltaic array combiner box and then connected in parallel to form a photovoltaic array grid-connected or independent power generation model for photovoltaic power generation, as shown in Figure 1. This model requires two conditions for stable power generation: First, the photovoltaic characteristics of all photovoltaic modules must be consistent and not damaged. The photovoltaic modules selected when the station is built are consistent and the current photovoltaic module technology is very solid can be guaranteed. Second, all photovoltaic modules must receive the same intensity of sunlight to ensure that the photovoltaic characteristics of each photovoltaic module are consistent. We have obtained results through experiments to prove that one of the photovoltaic cells on the photovoltaic cell string 1 is shaded from the sun. At this time, the output voltage PV1 of the photovoltaic cell string 1 is equal to between the voltage of a single photovoltaic module and 0, not The voltages of the photovoltaic cells on each series-connected module add up. When there is an unequal voltage output from PV cells connected in series from PV1 to PVn, there is a reverse diode to control the highest PV current return, then the output voltage is equal to the highest voltage, and the current is equal to the highest PV cell series current, and the output voltage cannot be achieved Equal to uniform voltage and superimposed current. Therefore, the electric energy output of light energy conversion is greatly reduced, and the conversion efficiency of light energy conversion electric energy is reduced.

In actual photovoltaic power generation applications, a fallen leaf, a tuft of bird droppings, a high-altitude shadow, and a dark cloud can easily make a photovoltaic power generation module in the entire power generation system irradiate unevenly, which makes the photovoltaic cells connected in series to output photovoltaic cells. Inconsistent characteristics will reduce the PV of the entire series, and the PV value in parallel will be inconsistent, so the current of the entire series cannot be accumulated into the combiner box. Therefore, in the existing photovoltaic power generation system, various reasons such as aging of photovoltaic panels, dust, rain, occlusion, partial sunlight, cloud cover, etc., will cause the output photoelectric characteristics of photovoltaic cells in series to be inconsistent, resulting in photovoltaic power generation efficiency Low, increase the cost of photovoltaic power generation system application, which is not conducive to the application and promotion of photovoltaic power generation system.

Summary of the invention

The invention discloses a photovoltaic power generation system, which mainly solves the low power generation efficiency caused by inconsistent power generation characteristics caused by various reasons such as aging, dust, rain and dew, obstruction of foreign objects, sun bias, clouds, etc. of each photovoltaic panel in the traditional photovoltaic power generation system The problem. The purpose is to improve the utilization efficiency of solar energy, increase the economic income of photovoltaic power stations, and realize rapid cost recovery of photovoltaic power stations.

The embodiment of the present invention provides a photovoltaic power generation system, which is characterized in that it includes:

m photovoltaic power generation subsystems, the m photovoltaic power generation subsystems are electrically connected to the combiner box in a parallel manner, where m is a positive integer;

Each of the photovoltaic power generation subsystems includes n photovoltaic power generation components, n voltage stabilizing components, and a boost component. Each photovoltaic power generation component is composed of p photovoltaic cells in series, and the output of each photovoltaic power generation component is The terminal is correspondingly connected to an input terminal of the voltage stabilizing component, the output ends of the n voltage stabilizing components are connected to the input terminal of the boosting component in parallel, and the output terminal of the boosting component is connected to the confluence The input end of the box is connected, wherein the voltage stabilizing component is used to stabilize the output voltage of each photovoltaic power generation component to a first predetermined voltage value, and the boost component is used to stabilize the output voltage of each photovoltaic power generation subsystem The output voltage is boosted from the first predetermined voltage value to a second predetermined voltage value, where n and p are respectively positive integers.

Preferably, the voltage stabilizing component adopts a DC/DC voltage regulator.

Preferably, the boosting component adopts a DC/DC booster or a DC/AC booster.

Preferably, the voltage stabilizing component is specifically configured to set the highest voltage value among the n output voltage values corresponding to the n photovoltaic power generation components as the first predetermined voltage value;

The voltage stabilizing component boosts and stabilizes the output voltage value of each photovoltaic power generation component to the first predetermined voltage value by means of boosting and stabilizing.

Preferably, the voltage stabilizing component is further configured to set the lowest voltage value among the n output voltage values corresponding to the n photovoltaic power generation components as the first predetermined voltage value;

The voltage stabilizing component decompresses and stabilizes the output voltage value of each photovoltaic power generation component to the first predetermined voltage value by means of pressure reduction and stabilization.

The present invention provides a photovoltaic power generation system, which mainly has the following beneficial effects:

1. The output voltage of each photovoltaic power generation module is stabilized to the first predetermined voltage value mainly through the voltage stabilizing component, so that all the photovoltaic power generation components output the same voltage value through the voltage stabilizing component, so as to avoid the photovoltaic cells after the photovoltaic panels are connected in series. Various reasons such as panel aging, dust, rain, occlusion, partial sunlight, clouds, etc. cause different voltage characteristics, which lead to energy loss between each other, thereby improving the efficiency of photovoltaic power generation;

2. Through the embodiments of the present invention, the traditional photovoltaic power generation system need not be limited to selecting photovoltaic panels with consistent characteristics, that is, photovoltaic power generation components, which is more practical;

3. The output voltage of multiple photovoltaic power generation subsystems is boosted and stabilized to a second predetermined voltage value through the boosting component, so that all photovoltaic power generation subsystems output the same voltage value through the boosting component, and converge the electric energy to The combiner box maximizes the output efficiency of photovoltaic panels, improves the utilization efficiency of solar energy into electric energy, increases the economic income of photovoltaic power stations, and realizes rapid recovery of photovoltaic power station costs;

4. The embodiment of the present invention can be realized only by adopting a DC/DC voltage stabilizer, a DC/DC booster or a DC/AC booster, without the need to upgrade the original structure of the photovoltaic panel to realize the cost Low, which is beneficial to promote the application and promotion of the present invention.

Description of the drawings

In order to explain the embodiments of the present invention or the technical solutions in the prior art more clearly, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only These are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative work.

Figure 1 is a schematic diagram of the structure of a photovoltaic power generation system in the prior art;

Figure 2 is a schematic structural diagram of a photovoltaic power generation system provided by the present invention.

detailed description

In order to enable those skilled in the art to better understand the solutions of the present invention, the technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only It is a part of the embodiments of the present invention, not all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative work shall fall within the protection scope of the present invention.

As shown in Figure 2, the present invention provides a photovoltaic power generation system, which specifically includes:

m photovoltaic power generation subsystems, the m photovoltaic power generation subsystems are electrically connected to the combiner box in parallel, where m is a positive integer;

It should be noted that the above-mentioned voltage stabilizing components can be DC/DC regulators, and the boosting components can be DC/DC boosters or DC/AC boosters, both of which are available on the market and belong to the prior art. The specific structure of the DC/DC regulator, DC/DC booster or DC/AC booster and the description of the specific voltage regulator circuit and boost circuit will not be repeated here.

Specifically, a number of photovoltaic cells are connected in series to form a photovoltaic power generation component, each photovoltaic power generation component is connected to a voltage stabilizing component, and the output end of the photovoltaic power generation component is connected to the input end of the voltage stabilizing component. The output ends are respectively connected to the input ends of the n voltage stabilizing components, and the output ends of the n voltage stabilizing components are connected in parallel with the input end of the boosting component to form a photovoltaic power generation subsystem. The output end of each booster component corresponds to the output end of a photovoltaic power generation subsystem, the prime number m photovoltaic power generation subsystems correspond to m booster components, and the m booster components are connected in parallel to the combiner box , Constitute the entire photovoltaic power generation system, where m and n are both positive integers.

In order to facilitate the understanding of the series-parallel characteristics and implementation principles of photovoltaic panels in the embodiments of the present invention, for example, as several photovoltaic cells are connected in series to form photovoltaic power generation components, when photovoltaic cells 1 and photovoltaic cells 2 are under the same conditions of sunlight Under irradiation, the output current value is the same. When photovoltaic cell 1 is blocked by half, the photovoltaic characteristics of photovoltaic cell 1 are inconsistent with those of photovoltaic cell 2, and its output voltage value is reduced. Because photovoltaic cell 1 and photovoltaic cell 2 have different output voltage values, photovoltaic cell 1 and photovoltaic cell 2 There is power loss between the two, but the output voltage of the photovoltaic cell 1 and the photovoltaic cell 2 is stabilized to a predetermined voltage value through the voltage stabilizing component, and the voltage is equalized.

Similarly, when photovoltaic power generation module 1 and photovoltaic power generation module 2 are connected in accordance with the traditional photovoltaic power generation system, they are connected in series. Therefore, under the same conditions of sunlight, their output current values are the same. When module 1 is blocked by half, the photovoltaic characteristics of photovoltaic power generation module 1 are inconsistent with those of photovoltaic power generation module 2, and the output current of photovoltaic power generation module 1 is lower than the output current of photovoltaic power generation module 2, and there will be some current backflow in photovoltaic power generation module 2 In the photovoltaic power generation module 1, in order to ensure that the photovoltaic power generation module 1 and the photovoltaic power generation module 2 can achieve the same voltage output, and are not affected by external conditions, they are connected in parallel. In order to achieve the same voltage in parallel, the photovoltaic power generation modules 1 and The voltage stabilizing component 1 and the voltage stabilizing component 2 corresponding to the photovoltaic power generation component 2 stabilize the voltages of the photovoltaic power generation component 1 and the photovoltaic power generation component 2 to a first predetermined voltage value. In this way, the voltage is equal and the current is accumulated, which avoids the inconsistency of the characteristics between the photovoltaic power generation module 1 and the photovoltaic power generation module 2, which causes the power loss between the photovoltaic power generation module 1 and the photovoltaic power generation module 2, and improves the photovoltaic power generation efficiency. This solves the technical problem that photovoltaic panels with different characteristics in the traditional photovoltaic power generation system will lose power to each other in series.

Specifically, the voltage stabilizing component in the embodiment of the present invention mainly adopts two output voltage stabilization design methods, one is the method of boosting voltage stabilization, and one of the photovoltaic power generation subsystems is taken as an example. The highest voltage value among the n output voltage values corresponding to the n photovoltaic power generation components is set to the first predetermined voltage value, and the n voltage stabilizing components respectively divide the above voltage value from the photovoltaic power generation subsystem in a step-up and stable manner The output voltage value of each photovoltaic power generation component except the highest photovoltaic power generation component is stabilized to the first predetermined voltage value; the other is to reduce the voltage and stabilize the output voltage corresponding to the n photovoltaic power generation components. The lowest voltage value among the voltage values is set to the first predetermined voltage value, and the n voltage stabilizing components are respectively used to reduce and stabilize each photovoltaic power generation system except the photovoltaic power generation component with the lowest voltage value. The output voltage values of the power generation components are stabilized to the first predetermined voltage value, so that the output voltage of each photovoltaic power generation component in the photovoltaic power generation subsystem is stabilized to the same set output value, so that the photovoltaic power generation system can realize Parallel connection to achieve equal voltage and current accumulation, thereby improving photovoltaic power generation efficiency.

It should be noted that each booster component is connected to a photovoltaic power generation subsystem, and each booster component is used to boost the output voltage value of the correspondingly connected photovoltaic power generation subsystem to a second predetermined voltage value to achieve high voltage and low The electric current facilitates the transmission and convergence of electric energy and reduces the power loss during the transmission. Then, the electric energy output by each photovoltaic power generation subsystem is gathered into the combiner box, and the electric energy is output and used through the combiner box. The first predetermined voltage in the embodiment of the present invention Both the value and the second predetermined voltage value can be set according to the actual power generation system requirements, and will not be repeated here.

It should be noted that in each photovoltaic power generation subsystem in the embodiment of the present invention, the n voltage stabilizing components are connected to one boosting component after being connected in parallel, and the n stabilizing components and the boosting component may be integrated Become a device. For the convenience of description, it is named after the optimizer. The optimizer includes n voltage regulator components and one boost component. Then the input port of the optimizer can be customized according to actual application scenarios. The input interface can be connected to a photovoltaic power generation component. The output end of the optimizer includes an output port of the booster component, which can be used to connect to the combiner box. Therefore, the technical solution of the embodiment of the present invention can be realized through multiple optimizers. The multiple optimizers are connected to the combiner box in parallel. Through the setting of the booster component of the optimizer output port, each optimizer outputs voltage Ensure the same, and realize the high-voltage and low-flow transmission of electric energy to the combiner box, avoiding the loss of electric energy during the transmission process.

Specifically, the above-mentioned multiple optimizers can also be integrated into one optimization device. The optimization device includes several above-mentioned optimizers. The output terminals of several internal optimizers are connected in parallel and set as an output interface. The output interface is connected to the combiner box. Connected, and the output voltages of several optimizers included in the optimization device are the same, so as to realize parallel connection.

The present invention provides a photovoltaic power generation system, which mainly stabilizes the output voltage of the photovoltaic power generation component to a first predetermined voltage value through a voltage stabilizing component, so that all photovoltaic power generation components output the same voltage value through the voltage stabilizing component, and avoid the problem of photovoltaic panels. After the series connection, the photovoltaic panels are aging, dust, rain, foreign objects, partial sunlight, clouds, etc., which cause different voltage characteristics, which cause power loss between each other, thereby improving the efficiency of photovoltaic power generation. At the same time, through the boost The component boosts and stabilizes the output voltage of multiple photovoltaic power generation subsystems to a second predetermined voltage value, so that all photovoltaic power generation subsystems output the same voltage value through the boost component, and converge the electrical energy to the combiner box in parallel to achieve voltage If the value is equal, the current is accumulated, thereby maximizing the power output efficiency of the photovoltaic panel, improving the utilization efficiency of converting solar energy into electrical energy, increasing the economic income of the photovoltaic power station, and realizing the rapid cost recovery of the photovoltaic power station.

The above-mentioned embodiments only express the preferred embodiments of the present invention, and the description is relatively specific and detailed, but it should not be understood as a limitation to the patent scope of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the concept of the present invention, several modifications, improvements and substitutions can be made, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention should be subject to the appended claims.

Claims

A photovoltaic power generation system, characterized by comprising:

m photovoltaic power generation subsystems, the m photovoltaic power generation subsystems are electrically connected to the combiner box in a parallel manner, where m is a positive integer;

Each of the photovoltaic power generation subsystems includes n photovoltaic power generation components, n voltage stabilizing components, and a boost component. Each photovoltaic power generation component is composed of p photovoltaic cells in series, and the output of each photovoltaic power generation component is The terminal is correspondingly connected to an input terminal of the voltage stabilizing component, the output ends of the n voltage stabilizing components are connected to the input terminal of the boosting component in parallel, and the output terminal of the boosting component is connected to the confluence The input end of the box is connected, wherein the voltage stabilizing component is used to stabilize the output voltage of each photovoltaic power generation component to a first predetermined voltage value, and the boost component is used to stabilize the output voltage of each photovoltaic power generation subsystem The output voltage is boosted from the first predetermined voltage value to a second predetermined voltage value, where n and p are respectively positive integers.
The photovoltaic power generation system of claim 1, wherein the voltage stabilizing component adopts a DC/DC voltage stabilizer.
The photovoltaic power generation system according to claim 1 or 2, characterized in that the boosting component adopts a DC/DC booster or a DC/AC booster.
The photovoltaic power generation system according to claim 3, wherein the voltage stabilizing component is specifically configured to set the highest voltage value among the n output voltage values corresponding to the n photovoltaic power generation components as the first predetermined value. Voltage value;

The voltage stabilizing component boosts and stabilizes the output voltage value of each photovoltaic power generation component to the first predetermined voltage value by means of boosting and stabilizing.
The photovoltaic power generation system according to claim 3, wherein the voltage stabilizing component is further configured to set the lowest voltage value among the n output voltage values corresponding to the n photovoltaic power generation components as the first Predetermined voltage value;

The voltage stabilizing component decompresses and stabilizes the output voltage value of each of the photovoltaic power generation components to the first predetermined voltage value by means of decompression and stabilization.