Intelligent photovoltaic module, has inverter that supplies alternating current to tracking algorithm point maximum power unit, and direct current to direct current converter controlled by maximum power unit

ES 2 249 147 B1

DESCRIPTION

Smart photovoltaic module.

Object of the invention

The present invention refers to a photovoltaic module that integrates electronic means that allow the individual maximum power point of each photovoltaic panel to be monitored and connected to other panels, according to a distributed architecture that allows reducing the power losses of the photovoltaic installation.

Background of the invention

A photovoltaic system for the transformation of solar energy into electrical energy is based on the use of multiple photovoltaic panels that are electrically connected to each other, obtaining, under optimal conditions, a total electrical power that would correspond to the sum of the maximum powers of each panel.

Traditionally, photovoltaic panels are arranged according to a centralized architecture, connecting the entire set to an inverter that supplies alternating current to the grid or installation to be powered. The inverter keeps track of the maximum power point of the entire array.

However, in any photovoltaic system there are electrical losses, close to 25% of the power, which are mainly due to mismatches between the different photovoltaic panels that make up the system and which are derived from the architecture of the system itself that makes when one of the panels cannot supply its full maximum power, the rest of the panels are affected and cannot give their maximum power either.

These mismatches are caused either by partial shadows, either by the different orientations and inclinations of the panels or by differences in the manufacturing process or by aging of the panels.

An alternative to try to solve these problems is described in German Patents No.^you. 19919766 and 4305326 in which, instead of the centralized architecture mentioned above, a partially distributed architecture is proposed in which the photovoltaic panels are divided into groups that are connected in series to respective DC-DC converters, these converters being the ones that are finally connect to the inverter. In this case, each of the DC-DC converters carries out its own monitoring of the maximum power point of the panels in its group, partly improving the efficiency of the system.

In any case, this system does not prevent significant power losses that depend on the number of panels connected in each group and the number of groups established.

Furthermore, these architectures are not suitable for future modifications or extensions to the installation.

Description of the invention

The object of the invention is the photovoltaic module that allows solving the problems set forth above by reducing all the losses due to the existing mismatches between the different photovoltaic panels.

For this, a photovoltaic module is proposed that is composed of a photovoltaic panel that integrates a series of electronic equipment and, in particular, 2 a DC-DC converter with its corresponding algorithm for monitoring the maximum power point of the module. The electronic circuit also incorporates elements that allow monitoring the status of the module and its communication with a remote control system.

The incorporation of a DC-DC converter in each photovoltaic module makes it possible to eliminate losses due to mismatches between the different modules of the system and extract the maximum power available in each one of them, regardless of the power supplied by the rest of the modules. .

With these modules, which we could call intelligent, a completely distributed system can be configured, in which the photovoltaic modules are connected to the inverter, through their corresponding DC-DC converters, which allows reducing all losses due to mismatches between modules.

In addition, it is very easy to size the installation and make future extensions and modifications, simply by adding or removing smart modules.

Additionally, the electronic circuit of the photovoltaic module integrates sensors that allow knowing the status of the module, as well as a communications module that sends this data to a control and supervision unit.

With the information collected from each of the modules of the photovoltaic plant or installation, monitoring, maintenance and fault detection tasks are facilitated.

Description of the drawings

To complement the description that is being made and in order to help a better understanding of the characteristics of the invention, a set of drawings is attached as an integral part of said description, where, with an illustrative and non-limiting nature, the following has been represented following:

Figure 1.- Shows a general diagram of the intelligent photovoltaic module object of the invention.

Figure 2.- Shows an architecture diagram of a photovoltaic installation made up of intelligent modules according to the object of the invention.

Figure 3.- Shows an installation scheme using conventional photovoltaic panels.

Figure 4.- Shows the output power curve of sunny and shaded panels.

Figure 5.- Shows the output power curve for an installation with 20 conventional panels. Preferred embodiment of the invention

The photovoltaic module object of the invention is made up of a photovoltaic panel (1) that integrates an electronic circuit (2) that comprises, among other elements, a DC-DC converter (3).

With the module that is the object of the invention, as can be seen in figure 2, completely distributed systems can be configured made up of photovoltaic panels (1), with their corresponding DC-DC converters (3), the latter being connected to an inverter (4) that feeds the corresponding installation.

The DC-DC converters (3) integrated in each panel (1), incorporate an algorithm for monitoring the maximum power point, which allows reducing all installation losses due to mismatches between the different panels (1).

The electronic circuit (2) also incorporates some

ES 2 249 147 B1 sensors (4) capable of determining the status of the module and transmitting this data, through a communications module (5), to a control and supervision unit (6) of the complete installation.

Monitoring, maintenance and fault detection of the entire photovoltaic installation are carried out in the control and supervision unit (6). The communications between modules and the unit (6) are carried out through the continuous wiring itself using FSK modulation, so no additional wiring is required.

The communication protocol is MODBUS-RTU, with master-slave architecture, the master being the control and supervision unit (6) and the slaves are each of the modules that send the voltage and current values ​​to the unit (6). both at the input and output of your DC-DC converter, as well as the operating temperature of the equipment.

Next, an operating example will be described, comparing the power obtained with a centralized system, with conventional modules, versus a distributed system with intelligent modules according to the object of the invention. Figures 4 and 5 show output power graphs included to illustrate this operating example.

Let's suppose a photovoltaic installation with 20 modules located for example on the roof of a building. In this type of application, it is impossible to avoid partial shadows, such as those generated by the building's chimney.

Let us also suppose that of the 20 modules of the installation, 5 are partially in shade due to the proximity of a chimney.

In figure 4, the output power curves for sunny modules and shaded modules have been represented. Specifically, it shows the maximum power output of a sunny module type BP580F (900 W / m²) and a shaded module (500 W / m²). It can be seen how, while the first has a maximum power of 82 W, the second reaches a maximum of 44 W. In addition, it can be seen how the currents for which the maximum power is obtained are different in each case. .

In the case of an installation made up of conventional photovoltaic modules, connected in series to a single converter with monitoring of the maximum power point, since all the modules are connected in series, they must conduct the same current, so the output power of the set corresponds to the curve represented in figure 4.

In this curve it can be seen how this series connection causes the appearance of a relative power maximum and an absolute power maximum. Therefore, in the best of cases, the absolute maximum power could be reached, which corresponds to a supplied power of 1213 W.

In the case of an architecture composed of 20 intelligent photovoltaic modules, according to the object of the invention, it is possible to obtain from each module its maximum available power, that is, 44 W for the five shaded modules and 82 W for the fifteen sunny modules. In this way, the maximum power of the installation would be 1450 W, which represents almost 20% more than with the traditional configuration.