WO2022020994A1

WO2022020994A1 - Photovoltaic power generation system and photovoltaic power generation method

Info

Publication number: WO2022020994A1
Application number: PCT/CN2020/104829
Authority: WO
Inventors: 廖华; 巴鲁斯卡·伦纳特
Original assignee: 西门子股份公司; 西门子（中国）有限公司
Priority date: 2020-07-27
Filing date: 2020-07-27
Publication date: 2022-02-03
Also published as: CN116210131A

Abstract

Provided are a photovoltaic power generation system and a photovoltaic power generation method. The photovoltaic power generation system comprises: at least two solar cell panels, at least two optimizers and an inverter, wherein each solar cell panel and each optimizer are connected in series to a direct-current bus; two ends of the direct-current bus are connected to the inverter; input ends of different optimizers are connected to different solar cell panels; the optimizer is used for controlling the solar cell panel connected to the input end thereof to output a current and a voltage at a maximum power point, shunting the current output by the solar cell panel connected to the input end thereof into a common current and an offset current, inputting the common current into the direct-current bus, converting the offset current to be equal to the common current and then inputting same into the direct-current bus; and the inverter is used for converting the common current input from the direct-current bus into a three-phase alternating current and then outputting same. By means of the present solution, the cost of performing photovoltaic power generation by using a photovoltaic power generation system can be reduced.

Description

光伏发电***和光伏发电方法Photovoltaic power generation system and photovoltaic power generation method

技术领域technical field

本发明涉及光伏发电技术领域，尤其涉及光伏发电***和光伏发电方法。The invention relates to the technical field of photovoltaic power generation, in particular to a photovoltaic power generation system and a photovoltaic power generation method.

背景技术Background technique

光伏发电(Photovoltaic power generation)是一种利用半导体界面的光生伏特效应而将光能直接转变为电能的技术。光伏发电***通常包括有相互串联的多个太阳能电池板，由于各个太阳能电池板的安装角度、安装坡度、所处环境温度等受光条件不同，导致各个太阳能电池板所能够产生的电流不同，而相互串联的各个太阳能电池板具有相同的输出电流，使得串联后各个太阳能电池板的输出电流等于各太阳能电池板所产生的最小电流，这将导致光伏发电***的输出功率小于实际可用功率，由于输出功率的损失导致太阳能没有得到充分利用。Photovoltaic power generation is a technology that directly converts light energy into electrical energy by utilizing the photovoltaic effect of the semiconductor interface. Photovoltaic power generation systems usually include multiple solar panels connected in series with each other. Due to the different light receiving conditions such as the installation angle, installation slope, and ambient temperature of each solar panel, the currents that can be generated by each solar panel are different. Each solar panel connected in series has the same output current, so that the output current of each solar panel after being connected in series is equal to the minimum current generated by each solar panel, which will cause the output power of the photovoltaic power generation system to be less than the actual available power, because the output power The loss of solar energy is not fully utilized.

为了解决由于不同太阳能电池板的受光条件不同而导致光伏发电***输出功率损失的问题，目前采用的解决方法是分别为每一个太阳能电池板配备优化器，每一个太阳能电池板与一个优化器相连接，各个优化器相互串联。太阳能电池板将所产生的功率传输给相连接的优化器，优化器追踪相连接太阳能电池板的最大功率点，缩小光伏发电***的输出功率与实际可用功率之间的差距，从而降低光伏发电***的功率损失。In order to solve the problem of output power loss of photovoltaic power generation system due to different light receiving conditions of different solar panels, the current solution is to equip each solar panel with an optimizer, and each solar panel is connected to an optimizer , the optimizers are connected in series with each other. The solar panels transmit the generated power to the connected optimizer, which tracks the maximum power point of the connected solar panels, narrowing the gap between the output power of the photovoltaic power generation system and the actual available power, thereby reducing the photovoltaic power generation system. power loss.

目前的光伏发电***中，太阳能电池板将所产生的功率传输给相连接的优化器，优化器对输入功率进行电压和电流转换后输出到直流母线，这就要求优化器具有足够的功率容量，以保证优化器能够接收相连接太阳能电池板所输出的全部功率，而优化器的成本与其功率容量相关，功率容量越大的优化器成本越高，因此利用现有光伏发电***进行光伏发电的成本较高。In the current photovoltaic power generation system, the solar panel transmits the generated power to the connected optimizer, and the optimizer converts the input power into voltage and current and outputs it to the DC bus, which requires the optimizer to have sufficient power capacity. In order to ensure that the optimizer can receive all the power output by the connected solar panels, and the cost of the optimizer is related to its power capacity, the larger the power capacity of the optimizer, the higher the cost. higher.

发明内容SUMMARY OF THE INVENTION

有鉴于此，本发明提供的光伏发电***和光伏发电方法，能够降低光伏发电的成本。In view of this, the photovoltaic power generation system and photovoltaic power generation method provided by the present invention can reduce the cost of photovoltaic power generation.

第一方面，本发明实施例提供了一种光伏发电***，包括：至少两个太阳能电池板、至少两个优化器和一个逆变器；In a first aspect, an embodiment of the present invention provides a photovoltaic power generation system, including: at least two solar panels, at least two optimizers, and an inverter;

所述至少两个太阳能电池板和所述至少两个优化器串联在直流母线上；the at least two solar panels and the at least two optimizers are connected in series on the DC bus;

所述直流母线的两端与所述逆变器相连接；Both ends of the DC bus are connected to the inverter;

每一个所述优化器的输入端与一个所述太阳能电池板相连接，其中，不同的所述优化器的输入端与不同的所述太阳能电池板相连接；The input end of each of the optimizers is connected to one of the solar cell panels, wherein the input ends of different optimizers are connected to different solar cell panels;

所述优化器，用于控制与其输入端相连接的所述太阳能电池板在最大功率点输出电流和电压，并将与其输入端相连接的所述太阳能电池板输出的电流分流为公共电流和偏差电流，使所述公共电流输入所述直流母线，并将所述偏差电流转换至与所述公共电流相等后输入所述直流母线；The optimizer is used to control the output current and voltage of the solar panel connected to its input terminal at the maximum power point, and divide the current output from the solar panel connected to its input terminal into a common current and a deviation current, so that the common current is input to the DC bus, and the offset current is converted to be equal to the common current and then input to the DC bus;

所述逆变器，用于将从所述直流母线输入的所述公共电流转换为三相交流电后输出。The inverter is used for converting the common current input from the DC bus into three-phase AC power and then outputting it.

在本发明实施例中，每一个太阳能电池板配备一个优化器，优化器可以将太阳能电池板输出的电流分流为公共电流和偏差电流，其中公共电流被直流输入直流母线以传输到逆变器，而偏差电流由优化器转换至与公共电流相等后输入直流母线以传输到逆变器。由于优化器仅接收偏差电流，因此优化器具有较小的功率容量便能够满足使用要求，而功率容量较小的优化器具有较低的成本，从而能够降低建造光伏发电***的成本，进而能够降低利用光伏发电***进行光伏发电的成本。In the embodiment of the present invention, each solar panel is equipped with an optimizer, and the optimizer can divide the current output by the solar panel into a common current and a bias current, wherein the common current is input to the DC bus by the DC to transmit to the inverter, The bias current is converted by the optimizer to be equal to the common current and then input to the DC bus for transmission to the inverter. Since the optimizer only receives the deviation current, the optimizer with a smaller power capacity can meet the usage requirements, and the optimizer with a smaller power capacity has a lower cost, which can reduce the cost of building a photovoltaic power generation system, which can reduce The cost of photovoltaic power generation using photovoltaic power generation systems.

在第一种可能的实现方式中，结合上述第一方面，光伏发电***的结构形式可以为：In a first possible implementation manner, combined with the above-mentioned first aspect, the structural form of the photovoltaic power generation system may be:

所述至少两个太阳能电池板顺次串联构成电池板串；The at least two solar panels are connected in series to form a panel string;

所述至少两个优化器的输出端顺次串联构成优化器串；The output ends of the at least two optimizers are connected in series to form an optimizer string;

位于所述电池板串第一端的一个所述太阳能电池板与所述逆变器相连接；one of the solar panels at the first end of the panel string is connected to the inverter;

位于所述优化器串第一端的一个所述优化器的输出端与位于所述电池板串第二端的一个所述太阳能电池板相连接；an output end of one of the optimizers located at the first end of the optimizer string is connected to one of the solar cell panels located at the second end of the battery panel string;

位于所述优化器串第二端的一个所述优化器的输出端与所述逆变器相连接；an output end of one of the optimizers at the second end of the optimizer string is connected to the inverter;

按照从所述电池板串第一端至第二端和从所述优化器串第一端至第二端的顺序，所述优化器串上的第n个所述优化器的输入端与所述电池板串上的第n个所述太阳能电池板相连接，其中，所述n为正整数，且所述n小于或等于所述太阳能电池板的总个数。In the order from the first end to the second end of the panel string and from the first end to the second end of the optimizer string, the input end of the nth optimizer on the optimizer string is the same as that of the optimizer string. The nth solar cell panels on the cell panel string are connected, wherein the n is a positive integer, and the n is less than or equal to the total number of the solar cell panels.

在本发明实施例中，各太阳能电池板顺次相连构成电池板串，各优化器的输出端顺次相连构成优化器串，电池板串和优化器串再相互串联构成直流母线，从太阳能电池板的输出电流中分流出的公共电流不通过优化器，这样可以减小优化器的功率需求，从而降低对于优化器体积和成本的要求。In the embodiment of the present invention, each solar panel is connected in sequence to form a panel string, the output ends of each optimizer are connected in sequence to form an optimizer string, and the panel string and the optimizer string are connected in series with each other to form a DC bus. The common current shunted from the output current of the board does not pass through the optimizer, so that the power requirement of the optimizer can be reduced, thereby reducing the requirements for the size and cost of the optimizer.

在第二种可能的实现方式中，结合上述第一方面，光伏发电***的结构形式可以为：In a second possible implementation manner, combined with the above-mentioned first aspect, the structural form of the photovoltaic power generation system may be:

所述太阳能电池板和所述优化器在所述直流母线上间隔设置；The solar cell panel and the optimizer are arranged at intervals on the DC bus;

按照所述直流母线上从所述太阳能电池板所在一端至所述优化器所在一端的顺序，第一个所述太阳能电池板与所述逆变器相连接，第m个优化器的输入端与第m个所述太阳能电池板相连接，第m个优化器的输出端与第m+1个所述太阳能电池板相连接，最后一个优化器的输出端与所述逆变器相连接，其中，所述m为正整数，且所述m小于或等于所述太阳能电池板的总个数。According to the sequence of the DC bus from the end where the solar panel is located to the end where the optimizer is located, the first solar panel is connected to the inverter, and the input end of the mth optimizer is connected to the inverter. The mth solar panel is connected, the output end of the mth optimizer is connected to the m+1th solar panel, and the output end of the last optimizer is connected to the inverter, wherein , the m is a positive integer, and the m is less than or equal to the total number of the solar cell panels.

在本发明实施例中，各太阳能电池板和各优化器间隔串联在直流母线上，各太阳能电池板之间没有直接的电连接，这使得优化器的布线更加方便，同时优化器的结构也可以更加简单，从而可以进一步降低光伏发电***的成本。In the embodiment of the present invention, each solar panel and each optimizer are connected in series on the DC bus, and there is no direct electrical connection between the solar panels, which makes the wiring of the optimizer more convenient, and the structure of the optimizer can also be Simpler, so that the cost of the photovoltaic power generation system can be further reduced.

在第三种可能的实现方式中，结合上述第一种可能的实现方式，所述优化器包括：隔离式DC/DC转换器。In a third possible implementation manner, in combination with the above-mentioned first possible implementation manner, the optimizer includes: an isolated DC/DC converter.

在本发明实施例中，隔离式DC/DC转换器初级是H桥转换器，次级是全波整流器，高频变压器用于隔离输入和输出，基于高频变压器不仅可以实现将偏差电流转换为公共电流，还能够将优化器的输入端和输出端隔离，保证能够对太阳能电池板的最大功率点进行跟踪，并保证能够将偏差电流转换为公共电流后输入直流母线。In the embodiment of the present invention, the primary of the isolated DC/DC converter is an H-bridge converter, the secondary is a full-wave rectifier, and the high-frequency transformer is used to isolate the input and output. Based on the high-frequency transformer, not only the deviation current can be converted into The common current can also isolate the input end and output end of the optimizer, ensuring that the maximum power point of the solar panel can be tracked, and that the deviation current can be converted into a common current and then input to the DC bus.

在第四种可能的实现方式中，结合上述第三种可能的实现方式，所述隔离式DC/DC转换器包括：第一电容、第二电容、第一开关管、第二开关管、第三开关管、第四开关管、变压器、第一电感、第一二极管和第二二极管；In a fourth possible implementation manner, combined with the above-mentioned third possible implementation manner, the isolated DC/DC converter includes: a first capacitor, a second capacitor, a first switch, a second switch, a first Three switch tubes, a fourth switch tube, a transformer, a first inductor, a first diode and a second diode;

所述第一电容的正极和负极分别与所述隔离式DC/DC转换器的两个输入端引脚相连接；The positive pole and the negative pole of the first capacitor are respectively connected with the two input pins of the isolated DC/DC converter;

所述第一开关管的漏极与所述第一电容的正极相连接，所述第一开关管的源极与所述第二开关管的漏极相连接，所述第二开关管的源极与所述第一电容的负极相连接；The drain of the first switch is connected to the anode of the first capacitor, the source of the first switch is connected to the drain of the second switch, and the source of the second switch is The pole is connected to the negative pole of the first capacitor;

所述第三开关管的漏极与所述第一电容的正极相连接，所述第三开关管的源极与所述第四开关管的漏极相连接，所述第四开关管的源极与所述第一电容的负极相连接；The drain of the third switch is connected to the anode of the first capacitor, the source of the third switch is connected to the drain of the fourth switch, and the source of the fourth switch is The pole is connected to the negative pole of the first capacitor;

所述第一开关管的源极和所述第三开关管的源极分别与所述变压器的两个输入端相连接；The source of the first switch tube and the source of the third switch tube are respectively connected to the two input ends of the transformer;

所述第一二极管的阳极与所述变压器的次级线圈的一端相连接，所述第二二极管的阳极与所述变压器的次级线圈的另一端相连接，且所述第二二极管的阴极与所述第一二极管的阴极相连接；The anode of the first diode is connected to one end of the secondary coil of the transformer, the anode of the second diode is connected to the other end of the secondary coil of the transformer, and the second the cathode of the diode is connected to the cathode of the first diode;

所述第一二极管的阴极与所述第一电感的一端相连接，所述第一电感的另一端与所述第二电容的正极相连接；The cathode of the first diode is connected to one end of the first inductor, and the other end of the first inductor is connected to the anode of the second capacitor;

所述第二电容的负极与所述变压器的次级线圈的中心抽头相连接；the negative pole of the second capacitor is connected to the center tap of the secondary coil of the transformer;

所述第二电容的正极和负极分别与所述隔离式DC/DC转换器的两个输出端引脚相连接；The positive pole and the negative pole of the second capacitor are respectively connected with the two output pins of the isolated DC/DC converter;

所述第一开关管、所述第二开关管、所述第三开关管和所述第四开关管的栅极均与第一控制器相连接；The gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all connected to the first controller;

所述第一控制器，用于根据各个所述太阳能电池板的输出电流，控制所述第一开关管、所述第二开关管、所述第三开关管和所述第四开关管的占空比，以控制与所述隔离式DC/DC转换器的两个输入端引脚相连接的太阳能电池板在最大功率点输出电流和电压，并将从所述隔离式DC/DC转换器的两个输入端引脚输入的所述偏差电流转换至与所述公共电流相等后从所述隔离式DC/DC转换器的两个输出端引脚输出。The first controller is configured to control the occupation of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube according to the output current of each of the solar cell panels. duty ratio to control the output current and voltage of the solar panel connected to the two input pins of the isolated DC/DC converter at the maximum power point, and will The offset current input from the two input pins is converted to be equal to the common current and then output from the two output pins of the isolated DC/DC converter.

在本发明实施例中，隔离式DC/DC转换器包括有多个开关管，在控制器的控制下各个开关管可以同步/异步导通或关断，从而准确的跟踪太阳能电池板的最大功率点，保证光伏发电***具有较低的功率损失。In the embodiment of the present invention, the isolated DC/DC converter includes a plurality of switch tubes, and each switch tube can be turned on or off synchronously/asynchronously under the control of the controller, so as to accurately track the maximum power of the solar panel point to ensure that the photovoltaic power generation system has a low power loss.

可选地，在第五种可能的实现方式中，结合上述第二种可能的实现方式，所述优化器包括：非隔离式DC/DC转换器。Optionally, in a fifth possible implementation manner, in combination with the foregoing second possible implementation manner, the optimizer includes: a non-isolated DC/DC converter.

在本发明实施例中，由于各太阳能电池板和各优化器间隔串联在直流母线上，采用非隔离式DC/DC转换器作为优化器，保证从太阳能电池板输出电流中分流出的公共电流和对偏差电流转换而获得的公共电流能够传输到直流母线上。In the embodiment of the present invention, since each solar panel and each optimizer are connected in series on the DC bus, a non-isolated DC/DC converter is used as the optimizer to ensure that the common current shunted from the output current of the solar panel and the The common current obtained by converting the offset current can be transferred to the DC bus.

可选地，在第六种可能的实现方式中，结合上述第五种可能的实现方式，所述非隔离式DC/DC转换器包括：第三电容、第四电容、第五开关管、第二电感和第三二极管；Optionally, in a sixth possible implementation manner, in combination with the fifth possible implementation manner, the non-isolated DC/DC converter includes: a third capacitor, a fourth capacitor, a fifth switch, a third Second inductor and third diode;

所述第三电容的正极和负极分别与所述非隔离式DC/DC转换器的两个输入端引脚相连接；The positive pole and the negative pole of the third capacitor are respectively connected with the two input pins of the non-isolated DC/DC converter;

所述第五开关管的漏极与所述第三电容的正极相连接，所述第五开关管的源极与所述第二电感的一端相连接，所述第二电感的另一端与所述第三电容的负极相连接；The drain of the fifth switch is connected to the positive pole of the third capacitor, the source of the fifth switch is connected to one end of the second inductance, and the other end of the second inductance is connected to the second inductance. The negative pole of the third capacitor is connected;

所述第三二极管的阴极与所述第五开关管的源极相连接，所述第三二极管的阳极与所述第四电容的负极相连接；The cathode of the third diode is connected to the source of the fifth switch tube, and the anode of the third diode is connected to the cathode of the fourth capacitor;

所述第四电容的正极与所述第三电容的负极相连接；The positive electrode of the fourth capacitor is connected to the negative electrode of the third capacitor;

所述第四电容的正极和负极分别与所述非隔离式DC/DC转换器的两个输出端引脚相连接；The positive pole and the negative pole of the fourth capacitor are respectively connected with the two output pins of the non-isolated DC/DC converter;

所述第五开关管的栅极与第二控制器相连接；The grid of the fifth switch tube is connected to the second controller;

所述第二控制器，用于根据各所述太阳能电池板的输出电流，控制所述第五开关管的占空比，以控制与所述非隔离式DC/DC转换器的两个输入端引脚相连接的太阳能电池板在最大功率点输出电流和电压，并将从所述非隔离式DC/DC转换器的两个输入端引脚输入的所述偏差电流转换至与所述公共电流相等后从所述非隔离式DC/DC转换器的两个输出端引脚输出。The second controller is used to control the duty cycle of the fifth switch tube according to the output current of each of the solar panels, so as to control the two input ends of the non-isolated DC/DC converter The pin-connected solar panel outputs current and voltage at the maximum power point, and converts the bias current input from the two input pins of the non-isolated DC/DC converter to the common current After being equalized, it is output from the two output pins of the non-isolated DC/DC converter.

在本发明实施例中，非隔离式DC/DC转换器相对于隔离式DC/DC转换器具有更加精简的结构，所包括的电气元件也更少，因此非隔离式DC/DC转换器相对于隔离式DC/DC转换器具有更低的成本和可靠性，从而采用非隔离式DC/DC转换器作为优化器可以进一步降低光伏发电***的成本，并能够提高利用光伏发电***进行光伏发电的可靠性。In the embodiment of the present invention, the non-isolated DC/DC converter has a more compact structure compared to the isolated DC/DC converter, and includes fewer electrical components. Therefore, the non-isolated DC/DC converter is relatively Isolated DC/DC converters have lower cost and reliability, so the use of non-isolated DC/DC converters as optimizers can further reduce the cost of photovoltaic power generation systems, and can improve the reliability of photovoltaic power generation using photovoltaic power generation systems sex.

在第七种可能的实现方式中，结合上述第一方面以及第一方面的第一种可能的实现方式、第二种可能的实现方式、第三种可能的实现方式、第四种可能的实现方式、第五种可能的实现方式和第六种可能的实现方式中的任意一个，所述公共电流与目标太阳能电池板的输出电流相等，其中，所述目标太阳能电池板为所述至少两个太阳能电池板中输出电流最小的一个所述太阳能电池板。In a seventh possible implementation manner, the above-mentioned first aspect and the first possible implementation manner, the second possible implementation manner, the third possible implementation manner, and the fourth possible implementation manner of the first aspect are combined any one of the manner, the fifth possible implementation manner and the sixth possible implementation manner, the common current is equal to the output current of the target solar panel, wherein the target solar panel is the at least two The solar panel with the smallest output current among the solar panels.

在本发明实施例中，将输出电流最小的一个太阳能电池板确定为目标太阳能电池板，进而将目标太阳能电池板的输出电流确定为公共电流，之后各个优化器根据确定出的公共电流对相应太阳能电池板输出的电流进行分流处理，这样与目标太阳能电池板相连接的优化器无偏差电流输入，减小了优化器将偏差电流转换至与公共电流相等时所造成的功率损失，从而可以进一步降低光伏发电***的功率损失。In the embodiment of the present invention, the solar panel with the smallest output current is determined as the target solar panel, and then the output current of the target solar panel is determined as the common current, and then each optimizer adjusts the corresponding solar panel according to the determined common current. The current output by the solar panel is shunted, so that the optimizer connected to the target solar panel has no bias current input, which reduces the power loss caused by the optimizer converting the bias current to be equal to the common current, which can further reduce Power losses in photovoltaic power generation systems.

第二方面本发明实施例还提供了一种基于上述第一方面或第一方面的任一可能的实现方式所提供光伏发电***的光伏发电方法，包括：Second aspect The embodiment of the present invention also provides a photovoltaic power generation method based on the photovoltaic power generation system provided by the first aspect or any possible implementation manner of the first aspect, including:

分别利用每一个所述优化器控制与该优化器的输入端相连接的所述太阳能电池板在最大功率点输出电流和电压；Using each of the optimizers respectively to control the output current and voltage of the solar panels connected to the input end of the optimizer at the maximum power point;

分别利用每一个所述优化器将与该优化器的输入端相连接的所述太阳能电池板输出的电流分流为公共电流和偏差电流，使所述公共电流输入所述直流母线，并将所述偏差电流转换至与所述公共电流相等后输入所述直流母线；Each of the optimizers is used to divide the current output by the solar panel connected to the input end of the optimizer into a common current and a bias current, so that the common current is input to the DC bus, and the The offset current is converted to be equal to the common current and then input to the DC bus;

利用所述逆变器将从所述直流母线输入的所述公共电流转换为三相交流电后输出。The common current input from the DC bus is converted into three-phase alternating current by the inverter and then output.

在本发明实施例中，利用优化器控制相应太阳能电池板在最大功率点输出电流和电压，以保证光伏发电过程中具有较低的功率损失，利用优化器将太阳能电池板输出的电流分流为公共电流和偏差电流，公共电流直接输入直流母线，而偏差电流由优化器转换至与公共电流相等后输入直流母线，由于优化器仅接收偏差电流，因此具有较小功率容量的优化器便能够满足使用要求，而功率容量小的优化器具有较低的成本，从而能够降低通过光伏发电***进行光伏发电的成本。In the embodiment of the present invention, the optimizer is used to control the output current and voltage of the corresponding solar panels at the maximum power point, so as to ensure low power loss during the photovoltaic power generation process, and the optimizer is used to divide the current output by the solar panels into common Current and bias current, the common current is directly input to the DC bus, and the bias current is converted by the optimizer to be equal to the common current and then input to the DC bus. Since the optimizer only receives the bias current, the optimizer with a smaller power capacity can meet the needs of use. requirements, while the optimizer with small power capacity has a lower cost, so that the cost of photovoltaic power generation through the photovoltaic power generation system can be reduced.

在第一种可能的实现方式中，结合上述第二方面，在所述分别利用每一个所述优化器将与该优化器的输入端相连接的所述太阳能电池板输出的电流分流为公共电流和偏差电流之前，进一步包括：In a first possible implementation manner, in combination with the above-mentioned second aspect, each of the optimizers is used to divide the current output by the solar panel connected to the input end of the optimizer into a common current. and bias current, further including:

从所述至少两个太阳能电池板中确定目标太阳能电池板，其中，所述目标太阳能电池板为所述至少两个太阳能电池板中输出电流最小的一个所述太阳能电池板；determining a target solar cell panel from the at least two solar cell panels, wherein the target solar cell panel is the solar cell panel with the smallest output current among the at least two solar cell panels;

将所述目标太阳能电池板的输出电流确定为所述公共电流。The output current of the target solar panel is determined as the common current.

在本发明实施例中，将输出电流最小的一个太阳能电池板确定为目标太阳能电池板，进而将目标太阳能电池板输出的电流确定为公共电流，使得目标太阳能电池板没有偏差电流，进而输入端与目标太阳能电池板相连接的优化器不需要对偏差电流进行转化，从而可以减少优化器对电流进行转换过程中的功率损失，因此可以进一步降低光伏发电过程中的功率损失。In the embodiment of the present invention, the solar panel with the smallest output current is determined as the target solar panel, and then the output current of the target solar panel is determined as the common current, so that the target solar panel has no bias current, and the input terminal is connected to the The optimizer connected to the target solar panel does not need to convert the bias current, so that the power loss in the process of converting the current by the optimizer can be reduced, so the power loss in the photovoltaic power generation process can be further reduced.

附图说明Description of drawings

图1是本发明一个实施例提供的一种光伏发电***的示意图；1 is a schematic diagram of a photovoltaic power generation system provided by an embodiment of the present invention;

图2是本发明一个实施例提供的另一种光伏发电***的示意图；2 is a schematic diagram of another photovoltaic power generation system provided by an embodiment of the present invention;

图3是本发明一个实施例提供的又一种光伏发电***的示意图；3 is a schematic diagram of yet another photovoltaic power generation system provided by an embodiment of the present invention;

图4是本发明一个实施例提供的一种隔离式DC/DC转换器的示意图；4 is a schematic diagram of an isolated DC/DC converter provided by an embodiment of the present invention;

图5是本发明一个实施例提供的一种非隔离式DC/DC转换器的示意图；5 is a schematic diagram of a non-isolated DC/DC converter provided by an embodiment of the present invention;

图6是本发明一个实施例提供的一种光伏发电方法的流程图。FIG. 6 is a flowchart of a photovoltaic power generation method provided by an embodiment of the present invention.

附图标记列表：List of reference numbers:

10：太阳能电池板 20：优化器 30：逆变器10: Solar panel 20: Optimizer 30: Inverter

21：隔离式DC/DC转换器 22：非隔离式DC/DC转换器 11-13：太阳能电池板21: Isolated DC/DC Converter 22: Non-isolated DC/DC Converter 11-13: Solar Panel

21-23：优化器 C1：电一电容 C2：第二电容21-23: Optimizer C1: Electric-Capacitor C2: Second Capacitor

C3：第三电容 C4：第四电容 S1：第一开关管C3: the third capacitor C4: the fourth capacitor S1: the first switch tube

S2：第二开关管 S3：第三开关管 S4：第四开关管S2: The second switch tube S3: The third switch tube S4: The fourth switch tube

S5：第五开关管 D1：第一二极管 D2：第二二极管S5: the fifth switch tube D1: the first diode D2: the second diode

D3：第三二极管 L1：第一电感 L2：第二电感D3: the third diode L1: the first inductor L2: the second inductor

T：变压器 100：光伏发电*** 600：光伏发电方法T: Transformer 100: Photovoltaic power generation system 600: Photovoltaic power generation method

601：利用优化器控制相连接的太阳能电池板在最大功率点工作601: Use the optimizer to control the connected solar panels to work at the maximum power point

602：利用优化器将相连接太阳能电池板输出的电流分流为公共电流和偏差电流602: Use the optimizer to split the current output by the connected solar panels into a common current and a bias current

603：利用逆变器将从直流母线输入的公共电流转换为三相交流电后输出603: Use the inverter to convert the common current input from the DC bus into three-phase AC power and output it

具体实施方式detailed description

如前所述，目前的光伏发电***中，为了解决由于不同太阳能电池板受光条件不同而导致整个光伏发电***输出功率损失的问题，分别为每一个太阳能电池板配备优化器，太阳能电池板将所产生的全部功率传输给相连接的优化器，优化器追踪相连接太阳能电池板的最大功率点，缩小光伏发电***的输出功率与实际可用功率之间的差距，以达到降低光伏发电***功率损失的目的。但是，太阳能电池板需要将所产生的全部功率传输给相连接的优化器，这就要求优化器具有足够的功率容量，以保证优化器能够接收相连接太阳能电池板输出的全部功率，而优化器的成本与其功率容量直接相关，功率容量越大的优化器其成本越高，因此现有的光伏发电***具有较高的建造成本，进而导致利用光伏发电***进行光伏发电的成本也较高。As mentioned above, in the current photovoltaic power generation system, in order to solve the problem of output power loss of the entire photovoltaic power generation system due to different light receiving conditions of different solar panels, each solar panel is equipped with an optimizer, and the solar panel will All the generated power is transmitted to the connected optimizer, and the optimizer tracks the maximum power point of the connected solar panels, narrowing the gap between the output power of the photovoltaic power generation system and the actual available power, so as to reduce the power loss of the photovoltaic power generation system. Purpose. However, the solar panel needs to transmit all the power generated to the connected optimizer, which requires the optimizer to have sufficient power capacity to ensure that the optimizer can receive the full power output from the connected solar panel, and the optimizer The cost of photovoltaic power generation is directly related to its power capacity. The larger the power capacity of the optimizer, the higher the cost. Therefore, the existing photovoltaic power generation system has a higher construction cost, which in turn leads to a higher cost of photovoltaic power generation using the photovoltaic power generation system.

本发明实施例中，各太阳能电池板和各优化器均串联在直流母线上，不同优化器的输入端与不同的太阳能电池板相连接，优化器能够控制与其输入端相连接的太阳能电池板在最大功率点输出电流和电压，同时优化器还能够将与其输入端相连接的太阳能电池板输出的电流分流为公共电流和偏差电流，所分流出的公共电流直接输入直流母线，而分流出的偏差电流由优化器转换至与公共电流相等后输入直流母线。由此可见，太阳能电池板输出的电流被分流为公共电流和偏差电流，其中较大的公共电流被直接输入直流母线，而较小的偏差电流输入优化器，优化器将偏差电流转换至与公共电流相等后输入直流母线，因此优化器仅需具有较小的功率容量便能够满足对偏差电流进行转换的要求，由于较小功率容量的优化器具有较低的成本，从而能够降低整个光伏发电***的建造成本，进而能够降低利用光伏发电***进行光伏发电的成本。In the embodiment of the present invention, each solar panel and each optimizer are connected in series on the DC bus, the input ends of different optimizers are connected to different solar panels, and the optimizer can control the solar panel connected to its input The maximum power point outputs current and voltage, and the optimizer can also divide the current output by the solar panel connected to its input into a common current and a bias current. The current is converted by the optimizer to be equal to the common current and fed into the DC bus. It can be seen that the current output by the solar panel is divided into the common current and the bias current, in which the larger common current is directly input to the DC bus, and the smaller bias current is input to the optimizer, which converts the bias current to the same value as the common current. After the current is equal, the DC bus is input, so the optimizer only needs to have a smaller power capacity to meet the requirements of converting the offset current. Since the optimizer with a smaller power capacity has a lower cost, it can reduce the entire photovoltaic power generation system. Therefore, the cost of photovoltaic power generation using photovoltaic power generation system can be reduced.

下面结合附图对本发明实施例提供的光伏发电***和光伏发电方法进行详细说明。The photovoltaic power generation system and photovoltaic power generation method provided by the embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

如图1所述，本发明所述提供了一种光伏发电***100，包括：至少两个太阳能电池板10、至少两个优化器20和一个逆变器30；As shown in FIG. 1 , the present invention provides a photovoltaic power generation system 100 , comprising: at least two solar cell panels 10 , at least two optimizers 20 and an inverter 30 ;

至少两个太阳能电池板10和至少两个优化器20串联在直流母线上；At least two solar panels 10 and at least two optimizers 20 are connected in series on the DC bus;

直流母线的两端与逆变器30相连接；Both ends of the DC bus are connected to the inverter 30;

每一个优化器20的输入端与一个太阳能电池板10相连接，其中，不同的优化器20的输入端与不同的太阳能电池板10相连接；The input end of each optimizer 20 is connected with one solar cell panel 10, wherein the input ends of different optimizers 20 are connected with different solar cell panels 10;

优化器20，用于控制与其输入端相连接的太阳能电池板10在最大功率点输出电流和电压，并将与其输入端相连接的太阳能电池板10输出的电流分流为公共电流和偏差电流，使公共电流输入直流母线，并将偏差电流转换至与公共电流相等后输入直流母线；The optimizer 20 is used to control the output current and voltage of the solar cell panel 10 connected to its input terminal at the maximum power point, and divide the output current of the solar cell panel 10 connected to its input terminal into a common current and a bias current, so that the The common current is input to the DC bus, and the deviation current is converted to be equal to the common current and then input to the DC bus;

逆变器30，用于将从直流母线输入的公共电流转换为三相交流电后输出。The inverter 30 is used for converting the common current input from the DC bus into three-phase AC power and outputting it.

在本发明实施例中，各太阳能电池板10和各优化器20均串联在直流母线上，不同优化器20的输入端与不同的太阳能电池板10相连接，一方面优化器20可以控制与其输入端相连接的太阳能电池板10在最大功率点输入电流和电压，另一方面优化器20还可以将其与输入端相连接的太阳能电池板10输出的电流分流为公共电流和偏差电流两部分，其中公共电流被直接输入直流母线，而偏差电流由优化器20转换至与公共电流相等后输入直流母线，直流母线上的公共电流被输入逆变器30，逆变器30将公共电流转换为三相交流电后输出。由此可见，优化器20不仅可以控制太阳能电池板10在最大功率点输出电流和电压，还能够将太阳能电池板10输出的电流分流为公共电流和偏差电流，公共电流被直接输入直流母线，而偏差电流被优化器20转换至与各个电流相等后输入直流母线，因此优化器20仅需具有较小的功率容量便能够满足对偏差电流进行转换的要求，由于具有较小功率容量的优化器20具有较低的成本，使得整个光伏发电***100具有较低的建造成本，从而能够降低利用光伏发电***100进行光伏发电的成本。In the embodiment of the present invention, each solar panel 10 and each optimizer 20 are connected in series on the DC bus, and the input ends of different optimizers 20 are connected to different solar panels 10. On the one hand, the optimizer 20 can control its input The solar panels 10 connected to the terminals input current and voltage at the maximum power point. On the other hand, the optimizer 20 can also divide the current output by the solar panels 10 connected to the input terminals into two parts, the common current and the offset current. The common current is directly input to the DC bus, and the bias current is converted to be equal to the common current by the optimizer 20 and then input to the DC bus. The common current on the DC bus is input to the inverter 30, and the inverter 30 converts the common current into three Output after alternating current. It can be seen that the optimizer 20 can not only control the output current and voltage of the solar panel 10 at the maximum power point, but also can divide the current output by the solar panel 10 into a common current and a bias current. The common current is directly input to the DC bus, while the The bias current is converted to be equal to each current by the optimizer 20 and then input to the DC bus, so the optimizer 20 only needs to have a smaller power capacity to meet the requirements for converting the bias current, because the optimizer 20 with a smaller power capacity With a lower cost, the entire photovoltaic power generation system 100 has a lower construction cost, so that the cost of photovoltaic power generation using the photovoltaic power generation system 100 can be reduced.

在本发明实施例中，太阳能电池板10所能够产生的电流和电压与其受光条件相关，随着受光条件的变化太阳能电池板10所能够产生的电流和电压也会发生变化，在特定受光条件下太阳能电池板10的工作点取决与太阳能电池板10所连接负载的大小。优化器20从相应传感器获取太阳能电池板10输出的电流和电压后，根据所获取到的电流和电流调节变换器的占空比以改变太阳能电池板10的负载，从而实现最大功率点的跟踪，使太阳能电池板10的工作点保持在最大功率点附近。In the embodiment of the present invention, the current and voltage that can be generated by the solar cell panel 10 are related to the light-receiving condition. The current and voltage that the solar cell panel 10 can generate will also change with the change of the light-receiving condition. Under certain light-receiving conditions The operating point of the solar cell panel 10 depends on the size of the load connected to the solar cell panel 10 . After the optimizer 20 acquires the current and voltage output by the solar panel 10 from the corresponding sensor, it adjusts the duty cycle of the converter according to the acquired current and current to change the load of the solar panel 10, so as to realize the tracking of the maximum power point, The operating point of the solar panel 10 is kept near the maximum power point.

可选地，在图1所示光伏发电***100的基础上，各太阳能电池板10和各优化器20均串联在直流母线上，根据太阳能电池板10和优化器20在直流母线上的排布方式不同，该光伏发电***100至少具有如下两种不同的结构形式：Optionally, on the basis of the photovoltaic power generation system 100 shown in FIG. 1 , each solar panel 10 and each optimizer 20 are connected in series on the DC bus, according to the arrangement of the solar panels 10 and the optimizers 20 on the DC bus. In different ways, the photovoltaic power generation system 100 has at least the following two different structural forms:

结构形式一：各太阳能电池板10依次串联，各优化器20依次串联，串联之后的各太阳能电池板10和串联之后的各优化器20相串联构成直流母线；Structural form 1: each solar panel 10 is connected in series, each optimizer 20 is connected in series, each solar panel 10 connected in series and each optimizer 20 connected in series are connected in series to form a DC bus;

结构形式二：太阳能电池板10和优化器20以相互间隔的方式串联在直流母线上，即相邻两个太阳能电池板10之间设置有一个优化器20，相邻两个优化器20之间设置有一个太阳能电池板10。Structural form 2: The solar panel 10 and the optimizer 20 are connected in series on the DC bus in a mutually spaced manner, that is, an optimizer 20 is arranged between two adjacent solar panels 10, and between two adjacent optimizers 20 A solar panel 10 is provided.

根据光伏发电***100的结构形式不同，太阳能电池板10和优化器20与逆变器30之间的连接方式也不同，下面以光伏发电***100包括3个太阳能电池板和3个优化器为例，对上述结构形式一和结构形式二的光伏发电***100进行分别说明。Depending on the structure of the photovoltaic power generation system 100, the connection between the solar panel 10, the optimizer 20 and the inverter 30 is also different. The photovoltaic power generation system 100 includes three solar panels and three optimizers as an example below. , the photovoltaic power generation systems 100 of the first structure form and the second structure form are described respectively.

针对上述结构形式一，如图2所示，太阳能电池板11、太阳能电池板12和太阳能电池板13顺次串联连构成电池板串，优化器21、优化器22和优化器23顺次串联构成优化器串，位于电池板串第一端的太阳能电池板13与逆变器30相连接，位于优化器串第一端的优化器23的输出端与位于电池板串第二端的太阳能电池板11相连接，位于优化器串第二端的一个优化器21的输出端与逆变器30相连接。优化器21的输入端与太阳能电池板11相连接，优化器22的输入端与太阳能电池板12相连接，优化器23的输入端与太阳能电池板13相连接。For the first structural form above, as shown in FIG. 2 , the solar panel 11 , the solar panel 12 and the solar panel 13 are connected in series to form a panel string, and the optimizer 21 , the optimizer 22 and the optimizer 23 are connected in series to form a series of panels. In the optimizer string, the solar panel 13 at the first end of the panel string is connected to the inverter 30, and the output end of the optimizer 23 at the first end of the optimizer string is connected to the solar panel 11 at the second end of the panel string. The output terminal of one optimizer 21 located at the second end of the optimizer string is connected to the inverter 30 . The input end of the optimizer 21 is connected to the solar panel 11 , the input end of the optimizer 22 is connected to the solar panel 12 , and the input end of the optimizer 23 is connected to the solar panel 13 .

在本发明实施例中，优化器21控制太阳能电池板11在最大功率点输出电流I1和电压V1，优化器22控制太阳能电池板12在最大功率点输出电流I2和电压V2，优化器23控制太阳能电池板13在最大功率点输出电流I3和电压V3。太阳能电池板11输出的电流I1被分流为公共电流I和偏差电流ΔI1，公共电流I流过各太阳能电池板汇入直流母线，偏差电流ΔI1输入优化器21，偏差电流ΔI1被优化器21转换至与公共电流I相等后流过各个优化器汇入直流母线，同时优化器21生成输出电压Vo1。太阳能电池板12输出的电流I2被分流为公共电流I和偏差电流ΔI2，公共电流I流过各太阳能电池板汇入直流母线，偏差电流ΔI2输入优化器22，偏差电流ΔI2被优化器22转换至与公共电流I相等后流过各个优化器汇入直流母线，同时优化器22生成输出电压Vo2。太阳能电池板13输出的电流I3被分流为公共电流I和偏差电流ΔI3，公共电流I流过各太阳能电池板汇入直流母线，偏差电流ΔI3输入优化器23，偏差电流ΔI3被优化器23转换至与公共电流I相等后流过各个优化器汇入直流母线，同时优化器23生成输出电压Vo3。In the embodiment of the present invention, the optimizer 21 controls the solar panel 11 to output the current I1 and the voltage V1 at the maximum power point, the optimizer 22 controls the solar panel 12 to output the current I2 and the voltage V2 at the maximum power point, and the optimizer 23 controls the solar energy The panel 13 outputs current I3 and voltage V3 at the maximum power point. The current I1 output by the solar panel 11 is divided into a common current I and an offset current ΔI1. The common current I flows through each solar panel and enters the DC bus. The offset current ΔI1 is input to the optimizer 21 , and the offset current ΔI1 is converted by the optimizer 21 to After being equal to the common current I, it flows through each optimizer and enters into the DC bus, and at the same time, the optimizer 21 generates an output voltage Vo1. The current I2 output by the solar panel 12 is divided into a common current I and an offset current ΔI2. The common current I flows through each solar panel and enters the DC bus. The offset current ΔI2 is input to the optimizer 22, and the offset current ΔI2 is converted by the optimizer 22 to After being equal to the common current I, it flows through each optimizer and enters into the DC bus, and at the same time, the optimizer 22 generates an output voltage Vo2. The current I3 output by the solar panel 13 is divided into a common current I and an offset current ΔI3. The common current I flows through each solar panel and enters the DC bus. The offset current ΔI3 is input to the optimizer 23, and the offset current ΔI3 is converted by the optimizer 23 to After being equal to the common current I, it flows through each optimizer and enters into the DC bus, and at the same time, the optimizer 23 generates an output voltage Vo3.

直流母线上的电流为公共电流I，直流母线上的电压等于Vdc＝V1+V2+V3+Vo1+Vo2+Vo3，逆变器30将直流母线输入的公共电流I和电压Vdc转换为三相交流电后输出。The current on the DC bus is the common current I, the voltage on the DC bus is equal to Vdc=V1+V2+V3+Vo1+Vo2+Vo3, the inverter 30 converts the common current I and the voltage Vdc input from the DC bus into three-phase alternating current output later.

针对上述结构形式二，如图3所示，太阳能电池板11、优化器21、太阳能电池板12、优化器22、太阳能电池板13和优化器23顺次串联在直流母线上，逆变器30与太阳能电池板11相连接，太阳能电池板11与优化器21的输入端相连接，优化器21的输出端与太阳能电池板12相连接，太阳能电池板12与优化器22的输入端相连接，优化器22的输出端与太阳能电池板13相连接，太阳能电池板13与优化器23的输入端相连接，优化器23的输出端与逆变器30相连接。For the second structural form, as shown in FIG. 3 , the solar panel 11 , the optimizer 21 , the solar panel 12 , the optimizer 22 , the solar panel 13 and the optimizer 23 are connected in series on the DC bus in sequence, and the inverter 30 is connected to the solar panel 11, the solar panel 11 is connected to the input end of the optimizer 21, the output end of the optimizer 21 is connected to the solar panel 12, and the solar panel 12 is connected to the input end of the optimizer 22, The output end of the optimizer 22 is connected to the solar panel 13 , the solar panel 13 is connected to the input end of the optimizer 23 , and the output end of the optimizer 23 is connected to the inverter 30 .

在本发明实施例中，优化器21控制太阳能电池板11在最大功率点输出电流I1和电压V1，优化器22控制太阳能电池板12在最大功率点输出电流I2和电压V2，优化器23控制太阳能电池板13在最大功率点输出电流I3和电压V3。太阳能电池板11输出的电流I1被分流为公共电流I和偏差电流ΔI1，公共电流I从优化器21的输出端汇入直流母线，偏差电流ΔI1输入优化器21后被优化器21转换至与公共电流I相等后汇入直流母线，同时优化器21生成输出电压Vo1。太阳能电池板12输出的电流I2被分流为公共电流I和偏差电流ΔI2，公共电流I从优化器22的输出端汇入直流母线，偏差电流ΔI2输入优化器22后被优化器22转换至与公共电流I相等后汇入直流母线，同时优化器22生成输出电压Vo2。太阳能电池板13输出的电流I3被分流为公共电流I和偏差电流ΔI3，公共电流I从优化器23的输出端汇入直流母线，偏差电流ΔI3输入优化器23后被优化器23转换至与公共电流I相等后汇入直流母线，同时优化器23生成输出电压Vo3。In the embodiment of the present invention, the optimizer 21 controls the solar panel 11 to output the current I1 and the voltage V1 at the maximum power point, the optimizer 22 controls the solar panel 12 to output the current I2 and the voltage V2 at the maximum power point, and the optimizer 23 controls the solar energy The panel 13 outputs current I3 and voltage V3 at the maximum power point. The current I1 output by the solar panel 11 is divided into a common current I and an offset current ΔI1, the common current I is fed into the DC bus from the output end of the optimizer 21, and the offset current ΔI1 is input into the optimizer 21 and then converted by the optimizer 21 to the same as the common current. After the currents I are equal, they flow into the DC bus, and at the same time, the optimizer 21 generates the output voltage Vo1. The current I2 output by the solar panel 12 is divided into a common current I and a bias current ΔI2, the common current I is fed into the DC bus from the output end of the optimizer 22, and the bias current ΔI2 is input into the optimizer 22 and then converted to the same value as the common current by the optimizer 22. The currents I are equalized and then flow into the DC bus, and the optimizer 22 generates the output voltage Vo2 at the same time. The current I3 output by the solar panel 13 is divided into a common current I and an offset current ΔI3, the common current I is fed into the DC bus from the output end of the optimizer 23, and the offset current ΔI3 is input into the optimizer 23 and then converted by the optimizer 23 to the same as the common current. After the currents I are equal, they flow into the DC bus, and at the same time, the optimizer 23 generates an output voltage Vo3.

需要说明的是，上述结构形式一和结构形式二的光伏发电***100，优化器20均能够将与其输入端相连接的太阳能电池板10输出的电流分流为公共电流和偏差电流，为了保证光伏发电***100具有较大的输出功率，在对太阳能电池板10输出的电流进行分流时应尽可能获得较大的公共电流和较小的偏差电流，较大的公共电流不进入优化器20而直接汇入直流母线，因此仅有较小的偏差电流进入优化器20，所以优化器20仅需具有较小的功率容量便能够满足对偏差电流进行转换的要求。It should be noted that, in the photovoltaic power generation systems 100 of the above-mentioned structural forms 1 and 2, the optimizer 20 can shunt the current output by the solar panel 10 connected to its input end into a common current and a bias current, in order to ensure photovoltaic power generation. The system 100 has a large output power. When shunting the current output by the solar panel 10, a large common current and a small deviation current should be obtained as much as possible. The large common current does not enter the optimizer 20 and is directly collected. into the DC bus, so only a small offset current enters the optimizer 20, so the optimizer 20 only needs to have a small power capacity to meet the requirements for converting the offset current.

可选地，在光伏发电***100中各太阳能电池板10和各优化器20的连接方式为上述结构形式一时，优化器20包括隔离式DC/DC转换器21。Optionally, when the connection between each solar cell panel 10 and each optimizer 20 in the photovoltaic power generation system 100 is the above-mentioned first structure, the optimizer 20 includes an isolated DC/DC converter 21 .

当光伏发电***100如上述结构形式一时，各太阳能电池板10相互串联构成电池板串，各优化器20的输出端相互串联构成优化器串，电池板串和优化器串相串联构成直流母线，而且每一个优化器20的输入端与一个太阳能电池板10相连接，不同优化器20的输入端与不同的太阳能电池板10相连接。为了保证能够将太阳能电池板10所输出的电流分流为公共电流和偏差电流，而且使公共电流能够直接输送给下一个太阳能电池板10或逆变器30，采用隔离式DC/DC转换器21来跟踪太阳能电池板10的最大功率点，并将来自太阳能电池板10的偏差电流转换至与公共电流相等后汇入直流母线。When the photovoltaic power generation system 100 is in the first structural form, the solar panels 10 are connected in series to form a panel string, the output terminals of the optimizers 20 are connected in series to form an optimizer string, and the panel string and the optimizer string are connected in series to form a DC bus. Moreover, the input terminal of each optimizer 20 is connected to one solar cell panel 10 , and the input terminals of different optimizers 20 are connected to different solar cell panels 10 . In order to ensure that the current output by the solar panel 10 can be divided into a common current and an offset current, and the common current can be directly supplied to the next solar panel 10 or the inverter 30, an isolated DC/DC converter 21 is used to The maximum power point of the solar panel 10 is tracked, and the offset current from the solar panel 10 is converted to be equal to the common current and then fed into the DC bus.

可选地，隔离式DC/DC转换器21用于控制太阳能电池板10在最大功率点工作，并将偏差电流转换至与公共电流相等后汇入直流母线，隔离式DC/DC转换器21的初级是H桥转换器，次级是全波整流器，高频变压器用于隔离输入和输出。Optionally, the isolated DC/DC converter 21 is used to control the solar panel 10 to work at the maximum power point, and convert the offset current to be equal to the common current and then sink into the DC bus. The primary is an H-bridge converter, the secondary is a full-wave rectifier, and a high-frequency transformer is used to isolate the input and output.

如图4所示，隔离式DC/DC转换器21包括：第一电容C1、第二电容C2、第一开关管S1、第二开关管S2、第三开关管S3、第四开关管S4、变压器T、第一电感L1、第一二极管D1和第二二极管D2；As shown in FIG. 4 , the isolated DC/DC converter 21 includes: a first capacitor C1, a second capacitor C2, a first switch S1, a second switch S2, a third switch S3, a fourth switch S4, Transformer T, first inductor L1, first diode D1 and second diode D2;

第一电容C1的正极和负极分别与隔离式DC/DC转换器21的两个输入端引脚A1和A2相连接；The positive pole and the negative pole of the first capacitor C1 are respectively connected with the two input pins A1 and A2 of the isolated DC/DC converter 21;

第一开关管S1的漏极与第一电容C1的正极相连接，第一开关管S1的源极与第二开关管S2的漏极相连接，第二开关管S2的源极与第一电容C1的负极相连接；The drain of the first switch S1 is connected to the positive electrode of the first capacitor C1, the source of the first switch S1 is connected to the drain of the second switch S2, and the source of the second switch S2 is connected to the first capacitor The negative pole of C1 is connected;

第三开关管S3的漏极与第一电容C1的正极相连接，第三开关管S3的源极与第四开关S4管的漏极相连接，第四开关管S4的源极与第一电容C1的负极相连接；The drain of the third switch S3 is connected to the positive electrode of the first capacitor C1, the source of the third switch S3 is connected to the drain of the fourth switch S4, and the source of the fourth switch S4 is connected to the first capacitor The negative pole of C1 is connected;

第一开关管S1的源极和第三开关管S3的源极分别与变压器T的两个输入端相连接；The source of the first switch S1 and the source of the third switch S3 are respectively connected to the two input ends of the transformer T;

第一二极管D1的阳极与变压器T的次级线圈的一端相连接，第二二极管D2的阳极与变压器T的次级线圈的另一端相连接，且第二二极管D2的阴极与第一二极管D1的阴极相连接；The anode of the first diode D1 is connected to one end of the secondary coil of the transformer T, the anode of the second diode D2 is connected to the other end of the secondary coil of the transformer T, and the cathode of the second diode D2 connected to the cathode of the first diode D1;

第一二极管D1的阴极与第一电感L1的一端相连接，第一电感L1的另一端与第二电容C2的正极相连接；The cathode of the first diode D1 is connected to one end of the first inductor L1, and the other end of the first inductor L1 is connected to the positive electrode of the second capacitor C2;

第二电容C2的负极与变压器T的次级线圈的中心抽头相连接；The negative pole of the second capacitor C2 is connected to the center tap of the secondary coil of the transformer T;

第二电容C2的正极和负极分别与隔离式DC/DC转换器21的两个输出端引脚A3和A4相连接；The positive pole and the negative pole of the second capacitor C2 are respectively connected with the two output pins A3 and A4 of the isolated DC/DC converter 21;

第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4的栅极均与第一控制器相连接；The gates of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 are all connected to the first controller;

第一控制器，用于根据各个太阳能电池板10的输出电流，控制第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4的占空比，以控制与两个输入端引脚A1和A2相连接的太阳能电池板10在最大功率点输出电流和电压，并将从两个输入端引脚A1和A2输入的偏差电流转换至与公共电流相等后从两个输出端引脚A3和A4输出。The first controller is used to control the duty ratio of the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 according to the output current of each solar panel 10, so as to control the The solar panel 10 connected to the two input pins A1 and A2 outputs current and voltage at the maximum power point, and converts the bias current input from the two input pins A1 and A2 to be equal to the common current from the two Output pin A3 and A4 output.

在本发明实施例中，隔离式DC/DC转换器21的两个输入端引脚A1和A2分别与相应太阳能电池板10的电流输入端和电流输出端相连接，隔离式DC/DC转换器21的两个输出端引脚A3和A4用于将各优化器20串联成优化器串，并实现优化器串与电池板串、逆变器30之间的连接。In the embodiment of the present invention, the two input pins A1 and A2 of the isolated DC/DC converter 21 are respectively connected to the current input and current output of the corresponding solar cell panel 10, and the isolated DC/DC converter The two output pins A3 and A4 of 21 are used to connect each optimizer 20 in series to form an optimizer string, and realize the connection between the optimizer string, the battery panel string and the inverter 30 .

在本发明实施例中，第一控制器根据各太阳能电池板10的输出电流和电压分别向第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4的栅极输送电平信号，使第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4同步/异步导通或关闭，以此控制第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4的占空比，从而使相连接太阳能电池板10工作的最大功率点，同时可以将从两个输入端引脚A1和A2输入的偏差电流转换至与公共电流相等后从两个输出端引脚A3和A4输出。In the embodiment of the present invention, the first controller transmits to the grids of the first switch S1 , the second switch S2 , the third switch S3 and the fourth switch S4 according to the output current and voltage of each solar cell panel 10 , respectively. A level signal is sent to make the first switch S1, the second switch S2, the third switch S3 and the fourth switch S4 synchronously/asynchronously turned on or off, so as to control the first switch S1 and the second switch S2, the duty ratio of the third switch S3 and the fourth switch S4, so as to connect the maximum power point of the solar panel 10, and at the same time, the bias current input from the two input pins A1 and A2 can be converted It is output from the two output pins A3 and A4 after being equal to the common current.

在本发明实施例中，第一开关管S1、第二开关管S2、第三开关管S3和第四开关管S4可以是MOS管或者绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)，上述四个开关管可以全部为MOS管、全部为IGBT或部分为MOS管而其余为IGBT，具体可以更具实际情况灵活选择。需要说明的是，当第一开关管S1/第二开关管S2/第三开关管S3/第四开关管S4为IGBT时，第一开关管S1/第二开关管S2/第三开关管S3/第四开关管S4的漏极是指IGBT的集电极，第一开关管S1/第二开关管S2/第三开关管S3/第四开关管S4的源极是指IGBT的发射极，第一开关管S1/第二开关管S2/第三开关管S3/第四开关管S4的栅极是指 IGBT的门极。In the embodiment of the present invention, the first switch transistor S1, the second switch transistor S2, the third switch transistor S3 and the fourth switch transistor S4 may be MOS transistors or insulated gate bipolar transistors (Insulated Gate Bipolar Transistor, IGBT), The above-mentioned four switch tubes can be all MOS tubes, all IGBTs, or some MOS tubes and the rest are IGBTs, which can be flexibly selected according to the actual situation. It should be noted that when the first switch S1/second switch S2/third switch S3/fourth switch S4 are IGBTs, the first switch S1/second switch S2/third switch S3 / The drain of the fourth switch S4 refers to the collector of the IGBT, the source of the first switch S1/the second switch S2/the third switch S3/the fourth switch S4 refers to the emitter of the IGBT, and the source of the first switch S1/the second switch S2/the third switch S3/the fourth switch S4 The gates of the first switch S1/the second switch S2/the third switch S3/the fourth switch S4 refer to the gate of the IGBT.

可选地，在光伏发电***100中各太阳能电池板10和各优化器20的连接方式为上述结构形式二时，优化器20包括非隔离式DC/DC转换器22。Optionally, when the connection mode of each solar cell panel 10 and each optimizer 20 in the photovoltaic power generation system 100 is the above-mentioned second structure, the optimizer 20 includes a non-isolated DC/DC converter 22 .

当光伏发电***100如上述结构形式二时，各太阳能电池板10和各优化器20间隔布置在直流母线上，由于各太阳能电池板10之间没有直接的电连接，为了保证能够将太阳能电池板10输出的电流分流为公共电流和偏差电流，并保证公共电流和被转换至与公共电流相等的偏差电流在优化器20的输出端汇合，采用非隔离式DC/DC转换器22来跟踪太阳能电池板10的最大功率点，并将来自太阳能电池板10的偏差电流转换至与公共电流相等后与分流出的公共电流一同汇入直流母线。When the photovoltaic power generation system 100 is in the second structural form, each solar cell panel 10 and each optimizer 20 are arranged on the DC bus at intervals. Since there is no direct electrical connection between the solar cell panels 10, in order to ensure that the solar cell panels can be connected The output current of 10 is divided into common current and bias current, and it is ensured that the common current and the bias current converted to be equal to the common current are combined at the output of the optimizer 20, and the non-isolated DC/DC converter 22 is used to track the solar cell The maximum power point of the panel 10 is converted, and the offset current from the solar panel 10 is converted to be equal to the common current and then fed into the DC bus together with the shunted common current.

可选地，非隔离式DC/DC转换器22用于控制太阳能电池板10在最大功率点工作，并将偏差电流转换至与公共电流相等后与公共电流一同汇入直流母线，此时非隔离式DC/DC转换器22可以是反极性电源转换器。如图5所示，非隔离式DC/DC转换器22包括：第三电容C3、第四电容C4、第五开关管S5、第二电感L2和第三二极管D3；Optionally, the non-isolated DC/DC converter 22 is used to control the solar panel 10 to work at the maximum power point, and convert the offset current to be equal to the common current and then flow into the DC bus together with the common current. At this time, the non-isolated The DC/DC converter 22 may be a reverse polarity power converter. As shown in FIG. 5 , the non-isolated DC/DC converter 22 includes: a third capacitor C3, a fourth capacitor C4, a fifth switch S5, a second inductor L2 and a third diode D3;

第三电容C3的正极和负极分别与非隔离式DC/DC转换器22的两个输入端引脚A5和A6相连接；The positive pole and the negative pole of the third capacitor C3 are respectively connected to the two input pins A5 and A6 of the non-isolated DC/DC converter 22;

第五开关管S5的漏极与第三电容C3的正极相连接，第五开关管S5的源极与第二电感L2的一端相连接，第二电感L2的另一端与第三电容C3的负极相连接；The drain of the fifth switch S5 is connected to the positive electrode of the third capacitor C3, the source of the fifth switch S5 is connected to one end of the second inductor L2, and the other end of the second inductor L2 is connected to the negative electrode of the third capacitor C3 connected;

第三二极管D3的阴极与第五开关管S5的源极相连接，第三二极管D3的阳极与第四电容C4的负极相连接；The cathode of the third diode D3 is connected to the source of the fifth switch tube S5, and the anode of the third diode D3 is connected to the cathode of the fourth capacitor C4;

第四电容C4的正极与第三电容C3的负极相连接；The positive electrode of the fourth capacitor C4 is connected to the negative electrode of the third capacitor C3;

第四电容C4的正极和负极分别与非隔离式DC/DC转换器22的两个输出端引脚A8和A7相连接；The positive pole and the negative pole of the fourth capacitor C4 are respectively connected with the two output pins A8 and A7 of the non-isolated DC/DC converter 22;

第五开关管S5的栅极与第二控制器相连接；The grid of the fifth switch tube S5 is connected to the second controller;

第二控制器，用于根据各太阳能电池板10的输出电流，控制第五开关管S5的占空比，以控制与两个输入端引脚A5和A6相连接的太阳能电池板10在最大功率点输出电流和电压，并将从两个输入端引脚A5和A6输入的偏差电流转换至与公共电流相等后从两个输出端引脚A8和A7输出。The second controller is used to control the duty cycle of the fifth switch tube S5 according to the output current of each solar cell panel 10, so as to control the solar cell panel 10 connected to the two input pins A5 and A6 at the maximum power Point output current and voltage, and convert the deviation current input from the two input pins A5 and A6 to be equal to the common current and output from the two output pins A8 and A7.

在本发明实施例中，第二控制器根据各太阳能电池板10的输出电流和电压向第五开关管S5的栅极输送电平信号，使第五开关管S5导通或关闭，以此控制第五开关管S5的占空比，从而使与非隔离式DC/DC转换器22的两个输入端引脚A5和A6相连接的太阳能电池板10工作在最大功率点，同时可以将从两个输入端引脚A5和A6输入的偏差电流转换至与公共电流相等后与分流出的公共电流一同汇入直流母线。由图3中优化器20的连接关系可知，非隔离式DC/DC转换器22中的输入端引脚A6与输出端引脚A8相连接。In the embodiment of the present invention, the second controller transmits a level signal to the gate of the fifth switch S5 according to the output current and voltage of each solar cell panel 10 to turn on or off the fifth switch S5, thereby controlling The duty cycle of the fifth switch tube S5, so that the solar panel 10 connected to the two input pins A5 and A6 of the non-isolated DC/DC converter 22 works at the maximum power point, and at the same time, the two The bias current input by the input pins A5 and A6 of each input terminal is converted to be equal to the common current and then merged into the DC bus together with the shared common current. It can be known from the connection relationship of the optimizer 20 in FIG. 3 that the input pin A6 of the non-isolated DC/DC converter 22 is connected to the output pin A8.

在本发明实施例中，第五开关管S5可以是MOS管或者绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor，IGBT)，具体可以更具实际情况灵活选择。需要说明的是，当第五开关管S5为IGBT时，第五开关管S5的漏极是指IGBT的集电极，第五开关管S5的源极是指IGBT的发射极，第五开关管S5的栅极是指IGBT的门极。In the embodiment of the present invention, the fifth switch S5 may be a MOS transistor or an insulated gate bipolar transistor (Insulated Gate Bipolar Transistor, IGBT), which may be flexibly selected according to actual conditions. It should be noted that when the fifth switch S5 is an IGBT, the drain of the fifth switch S5 refers to the collector of the IGBT, the source of the fifth switch S5 refers to the emitter of the IGBT, and the fifth switch S5 The gate refers to the gate of the IGBT.

可选地，在上述各个实施例所提供光伏发电***100的基础上，优化器20将太阳能电池板10输出的电流分流为公共电流和偏差电流，其中公共电流可以等于目标太阳能电池板10的输出电流，而目标太阳能电池板10是各个太阳能电池板10中输出电流最小的一个太阳能电池板10。Optionally, on the basis of the photovoltaic power generation system 100 provided in the above embodiments, the optimizer 20 divides the current output by the solar panel 10 into a common current and a bias current, wherein the common current may be equal to the output of the target solar panel 10 . current, and the target solar cell panel 10 is the solar cell panel 10 with the smallest output current among the solar cell panels 10 .

在本发明实施例中，各优化器20在将各太阳能电池板10输出的电流分流为公共电流和偏差电流时，首先可以根据各个太阳能电池板10的输出电流来确定公共电流的大小，具体可以将输出电流最小的一个太阳能电池板10确定为目标太阳能电池板10，进而将目标太阳能电池板10所输出电流的大小确定为公共电流。除输入端与目标太阳能电池板10相连接的优化器20除外，其他优化器20均根据所确定出公共电流将相连接太阳能电池板10输出的电流分流为公共电流和偏差电流，而且所分流出的公共电流和偏差电流均等于零。输入端与目标太阳能电池板10相连接的优化器20没有偏差电流输入。In the embodiment of the present invention, when each optimizer 20 divides the current output by each solar cell panel 10 into a common current and a bias current, the size of the common current may be determined first according to the output current of each solar cell panel 10, specifically, the size of the common current may be determined by One solar cell panel 10 with the smallest output current is determined as the target solar cell panel 10, and then the magnitude of the output current of the target solar cell panel 10 is determined as the common current. Except for the optimizer 20 whose input terminal is connected to the target solar panel 10, other optimizers 20 divide the current output by the connected solar panel 10 into a common current and a bias current according to the determined common current, and the shunted current The common and bias currents are equal to zero. The optimizer 20 whose input is connected to the target solar panel 10 has no bias current input.

需要说明的是，由于各太阳能电池板10的受光条件会发生变化，因此目标太阳能电池板10并不是固定的，相应的公共电流的大小也是动态变化的。It should be noted that since the light receiving conditions of each solar cell panel 10 will change, the target solar cell panel 10 is not fixed, and the magnitude of the corresponding common current is also dynamically changed.

在本发明实施例中，将各太阳能电池板10中输出电流最小的一个太阳能电池板10确定为目标太阳能电池板10，进而将目标太阳能电池板10所输出电流确定为公共电流，此时输入端与目标太阳能电池板10相连接的优化器10不需要对偏差电流进行转换，从而可以减少优化器10对偏差电流进行转换过程中的功率损失。In the embodiment of the present invention, the solar cell panel 10 with the smallest output current among the solar cell panels 10 is determined as the target solar cell panel 10, and then the output current of the target solar cell panel 10 is determined as the common current. At this time, the input terminal The optimizer 10 connected to the target solar cell panel 10 does not need to convert the offset current, so that the power loss in the process of converting the offset current by the optimizer 10 can be reduced.

下面介绍本发明实施例提供的光伏发电方法，该方法基于前述的光伏发电***100来实现。如无特别声明，下述光伏发电方法中涉及的太阳能电池板可为前述的太阳能电池板10，下述光伏发电方法中涉及的优化器可为前述的优化器20，下述光伏发电方法中涉及的逆变器可为前述的逆变器30。The photovoltaic power generation method provided by the embodiment of the present invention is described below, and the method is implemented based on the photovoltaic power generation system 100 described above. Unless otherwise stated, the solar cell panel involved in the following photovoltaic power generation method may be the aforementioned solar cell panel 10, the optimizer involved in the following photovoltaic power generation method may be the aforementioned optimizer 20, and the following photovoltaic power generation method involves The inverter can be the aforementioned inverter 30 .

本发明实施例提供的光伏发电方法中，优化器将太阳能电池板输出的电流分流为公共电流和偏差电流，优化器仅对输入的偏差电流进行转换，而无需接收太阳能电池板输出的全部电流，因此功率容量较小的优化器便能够满足使用要求。如图6所示，该光伏发电方法600 具体可以包括如下步骤：In the photovoltaic power generation method provided by the embodiment of the present invention, the optimizer divides the current output by the solar panel into a common current and a bias current, and the optimizer only converts the input bias current without receiving all the current output by the solar panel. Therefore, an optimizer with a smaller power capacity can meet the usage requirements. As shown in FIG. 6 , the photovoltaic power generation method 600 may specifically include the following steps:

步骤601：分别利用每一个优化器控制与该优化器的输入端相连接的太阳能电池板在最大功率点输出电流和电压；Step 601: use each optimizer to control the output current and voltage of the solar panel connected to the input end of the optimizer at the maximum power point;

步骤602：分别利用每一个优化器将与该优化器的输入端相连接的太阳能电池板输出的电流分流为公共电流和偏差电流，使公共电流输入直流母线，并将偏差电流转换至与公共电流相等后输入直流母线；Step 602: Use each optimizer to divide the current output by the solar panel connected to the input end of the optimizer into a common current and a bias current, so that the common current is input to the DC bus, and the bias current is converted to the same as the common current. Input the DC bus after equalization;

步骤603：利用逆变器将从直流母线输入的公共电流转换为三相交流电后输出。Step 603: Convert the common current input from the DC bus into three-phase AC power by using the inverter and output it.

在本发明实施例中，利用优化器控制相应太阳能电池板在最大功率点输出电流和电压，以保证光伏发电过程中具有较低的功率损失，利用优化器将太阳能电池板输出的电流分流为公共电流和偏差电流，公共电流直接输入直流母线，而偏差电流由优化器转换至与公共电流相等后输入直流母线，由于优化器仅接收偏差电流，因此具有较小功率容量的优化器便能够满足使用要求，而功率容量小的优化器具有较低的成本，从而能够降低通过光伏发电***进行光伏发电的成本。In the embodiment of the present invention, the optimizer is used to control the output current and voltage of the corresponding solar panels at the maximum power point, so as to ensure low power loss during the photovoltaic power generation process, and the optimizer is used to divide the current output by the solar panels into common Current and bias current, the common current is directly input to the DC bus, and the bias current is converted by the optimizer to be equal to the common current and then input to the DC bus. Since the optimizer only receives the bias current, the optimizer with a smaller power capacity can satisfy the use of requirements, while the optimizer with small power capacity has a lower cost, so that the cost of photovoltaic power generation through the photovoltaic power generation system can be reduced.

可选地，在图6所示光伏发电方法600的基础上，在利用优化器将太阳能电池板输出的电流分流为公共电流和偏差电流之前，可以将输出电流最小的一个太阳能电池板确定为目标太阳能电池板，进而将目标太阳能电池板输出的电流确定为公共电流，之后各个优化器根据所确定出的公共电流对相应太阳能电池板输出的电流进行分流。Optionally, on the basis of the photovoltaic power generation method 600 shown in FIG. 6 , before using the optimizer to divide the current output by the solar panels into the common current and the offset current, the solar panel with the smallest output current may be determined as the target. The solar panel, and then determine the current output by the target solar panel as the common current, and then each optimizer divides the current output by the corresponding solar panel according to the determined common current.

需要说明的是，上述各流程和各***结构图中不是所有的步骤和模块都是必须的，可以根据实际的需要忽略某些步骤或模块。各步骤的执行顺序不是固定的，可以根据需要进行调整。上述各实施例中描述的***结构可以是物理结构，也可以是逻辑结构，即，有些模块可能由同一物理实体实现，或者，有些模块可能分由多个物理实体实现，或者，可以由多个独立设备中的某些部件共同实现。It should be noted that not all steps and modules in the above-mentioned processes and system structure diagrams are necessary, and some steps or modules may be omitted according to actual needs. The execution order of each step is not fixed and can be adjusted as required. The system structure described in the above embodiments may be a physical structure or a logical structure, that is, some modules may be implemented by the same physical entity, or some modules may be implemented by multiple physical entities, or may be implemented by multiple physical entities. Some components in separate devices are implemented together.

以上各实施例中，硬件模块可以通过机械方式或电气方式实现。例如，一个硬件模块可以包括永久性专用的电路或逻辑(如专门的处理器，FPGA或ASIC)来完成相应操作。硬件模块还可以包括可编程逻辑或电路(如通用处理器或其它可编程处理器)，可以由软件进行临时的设置以完成相应操作。具体的实现方式(机械方式、或专用的永久性电路、或者临时设置的电路)可以基于成本和时间上的考虑来确定。In the above embodiments, the hardware modules may be implemented mechanically or electrically. For example, a hardware module may include permanent dedicated circuits or logic (eg, dedicated processors, FPGAs or ASICs) to perform corresponding operations. The hardware modules may also include programmable logic or circuits (eg, general-purpose processors or other programmable processors), which may be temporarily set by software to complete corresponding operations. The specific implementation (mechanical, or dedicated permanent circuit, or temporarily provided circuit) can be determined based on cost and time considerations.

上文通过附图和优选实施例对本发明进行了详细展示和说明，然而本发明不限于这些已揭示的实施例，基与上述多个实施例本领域技术人员可以知晓，可以组合上述不同实施例中的代码审核手段得到本发明更多的实施例，这些实施例也在本发明的保护范围之内。The present invention is shown and described in detail above through the accompanying drawings and preferred embodiments. However, the present invention is not limited to these disclosed embodiments. Those skilled in the art can know that the above-mentioned different embodiments can be combined based on the above-mentioned multiple embodiments. More embodiments of the present invention can be obtained by the code review method in the present invention, and these embodiments are also within the protection scope of the present invention.

Claims

光伏发电***(100)，包括：至少两个太阳能电池板(10)、至少两个优化器(20)和一个逆变器(30)；A photovoltaic power generation system (100), comprising: at least two solar cell panels (10), at least two optimizers (20) and an inverter (30);

所述至少两个太阳能电池板(10)和所述至少两个优化器(20)串联在直流母线上；The at least two solar cell panels (10) and the at least two optimizers (20) are connected in series on the DC bus;

所述直流母线的两端与所述逆变器(30)相连接；Both ends of the DC bus are connected to the inverter (30);

每一个所述优化器(20)的输入端与一个所述太阳能电池板(10)相连接，其中，不同的所述优化器(20)的输入端与不同的所述太阳能电池板(10)相连接；The input of each of the optimizers (20) is connected to one of the solar panels (10), wherein the inputs of different optimizers (20) are connected to different solar panels (10) connected;

所述优化器(20)，用于控制与其输入端相连接的所述太阳能电池板(10)在最大功率点输出电流和电压，并将与其输入端相连接的所述太阳能电池板(10)输出的电流分流为公共电流和偏差电流，使所述公共电流输入所述直流母线，并将所述偏差电流转换至与所述公共电流相等后输入所述直流母线；The optimizer (20) is used to control the solar cell panel (10) connected to its input end to output current and voltage at the maximum power point, and to control the solar cell panel (10) connected to its input end The output current is divided into a common current and a bias current, so that the common current is input to the DC bus, and the bias current is converted to be equal to the common current and then input to the DC bus;

所述逆变器(30)，用于将从所述直流母线输入的所述公共电流转换为三相交流电后输出。The inverter (30) is used for converting the common current input from the DC bus into three-phase AC power and then outputting it.
根据权利要求1所述的***(100)，其中，The system (100) of claim 1, wherein,

所述至少两个太阳能电池板(10)顺次串联构成电池板串；The at least two solar cell panels (10) are connected in series to form a cell panel string;

所述至少两个优化器(20)的输出端顺次串联构成优化器串；The output ends of the at least two optimizers (20) are connected in series to form an optimizer string;

位于所述电池板串第一端的一个所述太阳能电池板(10)与所述逆变器(30)相连接；One of the solar cell panels (10) located at the first end of the cell panel string is connected to the inverter (30);

位于所述优化器串第一端的一个所述优化器(20)的输出端与位于所述电池板串第二端的一个所述太阳能电池板(10)相连接；An output end of one of the optimizers (20) located at the first end of the optimizer string is connected to one of the solar cell panels (10) located at the second end of the battery panel string;

位于所述优化器串第二端的一个所述优化器(20)的输出端与所述逆变器(30)相连接；An output end of one of the optimizers (20) located at the second end of the optimizer string is connected to the inverter (30);

按照从所述电池板串第一端至第二端和从所述优化器串第一端至第二端的顺序，所述优化器串上的第n个所述优化器(20)的输入端与所述电池板串上的第n个所述太阳能电池板(10)相连接，其中，所述n为正整数，且所述n小于或等于所述太阳能电池板(10)的总个数。In order from the first end to the second end of the panel string and from the first end to the second end of the optimizer string, the input end of the nth optimizer (20) on the optimizer string connected to the nth solar cell panel (10) on the cell panel string, wherein the n is a positive integer, and the n is less than or equal to the total number of the solar cell panels (10) .
根据权利要求1所述的***(100)，其中，The system (100) of claim 1, wherein,

所述太阳能电池板(10)和所述优化器(20)在所述直流母线上间隔设置；The solar cell panel (10) and the optimizer (20) are arranged at intervals on the DC bus;

按照所述直流母线上从所述太阳能电池板(10)所在一端至所述优化器(20)所在一端的顺序，第一个所述太阳能电池板(10)与所述逆变器(30)相连接，第m个优化器(20)的输入端与第m个所述太阳能电池板(10)相连接，第m个优化器(20)的输出端与第m+1个所述太阳能电池板(10)相连接，最后一个优化器(20)的输出端与所述逆变器(30)相连接，其中，所述m为正整数，且所述m小于或等于所述太阳能电池板(10)的总个数。According to the sequence on the DC bus from the end where the solar panel (10) is located to the end where the optimizer (20) is located, the first solar panel (10) and the inverter (30) connected, the input end of the mth optimizer (20) is connected with the mth solar cell panel (10), and the output end of the mth optimizer (20) is connected with the m+1th solar cell The panels (10) are connected, and the output end of the last optimizer (20) is connected to the inverter (30), wherein the m is a positive integer, and the m is less than or equal to the solar panel (10) total number.
根据权利要求2所述的***(100)，其中，The system (100) of claim 2, wherein,

所述优化器(20)包括：隔离式DC/DC转换器(21)。The optimizer (20) comprises: an isolated DC/DC converter (21).
根据权利要求4所述的***(100)，其中，所述隔离式DC/DC转换器(21)包括：第一电容、第二电容、第一开关管、第二开关管、第三开关管、第四开关管、变压器、第一电感、第一二极管和第二二极管；The system (100) according to claim 4, wherein the isolated DC/DC converter (21) comprises: a first capacitor, a second capacitor, a first switch, a second switch, and a third switch , a fourth switch tube, a transformer, a first inductor, a first diode and a second diode;

所述第一电容的正极和负极分别与所述隔离式DC/DC转换器(21)的两个输入端引脚相连接；The positive pole and the negative pole of the first capacitor are respectively connected with the two input pins of the isolated DC/DC converter (21);

所述第一开关管的漏极与所述第一电容的正极相连接，所述第一开关管的源极与所述第二开关管的漏极相连接，所述第二开关管的源极与所述第一电容的负极相连接；The drain of the first switch is connected to the anode of the first capacitor, the source of the first switch is connected to the drain of the second switch, and the source of the second switch is The pole is connected to the negative pole of the first capacitor;

所述第三开关管的漏极与所述第一电容的正极相连接，所述第三开关管的源极与所述第四开关管的漏极相连接，所述第四开关管的源极与所述第一电容的负极相连接；The drain of the third switch is connected to the anode of the first capacitor, the source of the third switch is connected to the drain of the fourth switch, and the source of the fourth switch is The pole is connected to the negative pole of the first capacitor;

所述第一开关管的源极和所述第三开关管的源极分别与所述变压器的两个输入端相连接；The source of the first switch tube and the source of the third switch tube are respectively connected to the two input ends of the transformer;

所述第一二极管的阳极与所述变压器的次级线圈的一端相连接，所述第二二极管的阳极与所述变压器的次级线圈的另一端相连接，且所述第二二极管的阴极与所述第一二极管的阴极相连接；The anode of the first diode is connected to one end of the secondary coil of the transformer, the anode of the second diode is connected to the other end of the secondary coil of the transformer, and the second the cathode of the diode is connected to the cathode of the first diode;

所述第一二极管的阴极与所述第一电感的一端相连接，所述第一电感的另一端与所述第二电容的正极相连接；The cathode of the first diode is connected to one end of the first inductor, and the other end of the first inductor is connected to the anode of the second capacitor;

所述第二电容的负极与所述变压器的次级线圈的中心抽头相连接；the negative pole of the second capacitor is connected to the center tap of the secondary coil of the transformer;

所述第二电容的正极和负极分别与所述隔离式DC/DC转换器(21)的两个输出端引脚相连接；The positive pole and the negative pole of the second capacitor are respectively connected with the two output pins of the isolated DC/DC converter (21);

所述第一开关管、所述第二开关管、所述第三开关管和所述第四开关管的栅极均与第一控制器相连接；The gates of the first switch tube, the second switch tube, the third switch tube and the fourth switch tube are all connected to the first controller;

所述第一控制器，用于根据各个所述太阳能电池板(10)的输出电流，控制所述第一开关管、所述第二开关管、所述第三开关管和所述第四开关管的占空比，以控制与所述隔离式DC/DC转换器(21)的两个输入端引脚相连接的太阳能电池板(10)在最大功率点输出电流和电压，并将从所述隔离式DC/DC转换器(21)的两个输入端引脚输入的所述偏差电流转换至与所述公共电流相等后从所述隔离式DC/DC转换器(21)的两个输出端引脚输出。The first controller is configured to control the first switch tube, the second switch tube, the third switch tube and the fourth switch according to the output current of each of the solar cell panels (10) duty cycle of the tube to control the output current and voltage of the solar panel (10) connected to the two input pins of the isolated DC/DC converter (21) at the maximum power point, and will The bias current input from the two input pins of the isolated DC/DC converter (21) is converted to the two outputs from the isolated DC/DC converter (21) after being equal to the common current terminal pin output.
根据权利要求3所述的***(100)，其中，The system (100) of claim 3, wherein,

所述优化器(20)包括：非隔离式DC/DC转换器(22)。The optimizer (20) includes a non-isolated DC/DC converter (22).
根据权利要求6所述的***(100)，其中，所述非隔离式DC/DC转换器(22)包括：第三电容、第四电容、第五开关管、第二电感和第三二极管；The system (100) according to claim 6, wherein the non-isolated DC/DC converter (22) comprises: a third capacitor, a fourth capacitor, a fifth switch, a second inductor and a third diode Tube;

所述第三电容的正极和负极分别与所述非隔离式DC/DC转换器(22)的两个输入端引脚相连接；The positive pole and the negative pole of the third capacitor are respectively connected with the two input pins of the non-isolated DC/DC converter (22);

所述第五开关管的漏极与所述第三电容的正极相连接，所述第五开关管的源极与所述第二电感的一端相连接，所述第二电感的另一端与所述第三电容的负极相连接；The drain of the fifth switch is connected to the positive pole of the third capacitor, the source of the fifth switch is connected to one end of the second inductance, and the other end of the second inductance is connected to the second inductance. The negative pole of the third capacitor is connected;

所述第三二极管的阴极与所述第五开关管的源极相连接，所述第三二极管的阳极与所述第四电容的负极相连接；The cathode of the third diode is connected to the source of the fifth switch tube, and the anode of the third diode is connected to the cathode of the fourth capacitor;

所述第四电容的正极与所述第三电容的负极相连接；The positive electrode of the fourth capacitor is connected to the negative electrode of the third capacitor;

所述第四电容的正极和负极分别与所述非隔离式DC/DC转换器(22)的两个输出端引脚相连接；The positive pole and the negative pole of the fourth capacitor are respectively connected with the two output pins of the non-isolated DC/DC converter (22);

所述第五开关管的栅极与第二控制器相连接；The grid of the fifth switch tube is connected to the second controller;

所述第二控制器，用于根据各所述太阳能电池板(10)的输出电流，控制所述第五开关管的占空比，以控制与所述非隔离式DC/DC转换器(22)的两个输入端引脚相连接的太阳能电池板(10)在最大功率点输出电流和电压，并将从所述非隔离式DC/DC转换器(22)的两个输入端引脚输入的所述偏差电流转换至与所述公共电流相等后从所述非隔离式DC/DC转换器(22)的两个输出端引脚输出。The second controller is configured to control the duty cycle of the fifth switch tube according to the output current of each of the solar cell panels (10), so as to control the non-isolated DC/DC converter (22) ) of the solar panel (10) connected to the two input pins of the solar panel output current and voltage at the maximum power point, and will be input from the two input pins of the non-isolated DC/DC converter (22) The offset current is converted to be equal to the common current and then output from the two output pins of the non-isolated DC/DC converter (22).
根据权利要求1-7中任一所述的***(100)，其中，The system (100) according to any of claims 1-7, wherein,

所述公共电流与目标太阳能电池板(20)的输出电流相等，其中，所述目标太阳能电池板(20)为所述至少两个太阳能电池板(10)中输出电流最小的一个所述太阳能电池板(10)。The common current is equal to the output current of the target solar cell panel (20), wherein the target solar cell panel (20) is the solar cell with the smallest output current among the at least two solar cell panels (10). plate (10).
根据权利要求1-8中任一所述光伏发电***(100)的光伏发电方法(600)，包括：The photovoltaic power generation method (600) of the photovoltaic power generation system (100) according to any one of claims 1-8, comprising:

分别利用每一个所述优化器(20)控制与该优化器(20)的输入端相连接的所述太阳能电池板(10)在最大功率点输出电流和电压；Using each of the optimizers (20) respectively to control the solar cell panels (10) connected to the input end of the optimizer (20) to output current and voltage at the maximum power point;

分别利用每一个所述优化器(20)将与该优化器(20)的输入端相连接的所述太阳能电池板(10)输出的电流分流为公共电流和偏差电流，使所述公共电流输入所述直流母线，并将所述偏差电流转换至与所述公共电流相等后输入所述直流母线；Using each of the optimizers (20) respectively, the current output by the solar cell panel (10) connected to the input end of the optimizer (20) is divided into a common current and a deviation current, so that the common current is input the DC bus, converting the offset current to be equal to the common current and then inputting the DC bus;

利用所述逆变器(30)将从所述直流母线输入的所述公共电流转换为三相交流电后输出。The common current input from the DC bus is converted into three-phase AC power by the inverter (30) and then output.
根据权利要求9所述的方法(600)，其中，在所述分别利用每一个所述优化器(20)将与该优化器(20)的输入端相连接的所述太阳能电池板(10)输出的电流分流为公共电流和偏差电流之前，进一步包括：The method (600) according to claim 9, wherein said solar panel (10) connected to the input of each said optimizer (20) is used separately in said optimizer (20) Before the output current is divided into common current and offset current, it further includes:

从所述至少两个太阳能电池板(10)中确定目标太阳能电池板(10)，其中，所述目标太阳能电池板(20)为所述至少两个太阳能电池板(10)中输出电流最小的一个所述太阳能电池板(10)；A target solar cell panel (10) is determined from the at least two solar cell panels (10), wherein the target solar cell panel (20) is the one with the smallest output current among the at least two solar cell panels (10). one of said solar panels (10);

将所述目标太阳能电池板(10)的输出电流确定为所述公共电流。The output current of the target solar panel (10) is determined as the common current.