DESCRIPTION

Technical field

The present invention relates to an auxiliary photovoltaic plant of a type for generating energy.

Background art

Photovoltaic generators have been known for some time; that is, devices which transform solar energy into electricity. This type of plant is used in very diverse shapes, among which plants of the fixed type that are usable in structures/buildings both in dwellings and industrial applications, mostly in association with the electrical energy network (grid-connect plants). These systems must be considered as being of a structural type, as they are designed ad hoc and stably fixed to the relative user outlets.

There are however also independent photovoltaic installations for energy production that is sufficient for a limited and dedicated user device, such as for example users for the production of hot water or of electricity for supply of particular users that have a calculated consumption (standalone plants).

Aim of the invention

The present invention has the form of a small machine defining a photovoltaic plant for energy production, for supplementing, as it is connected in parallel to the network, the energy supplied by the normal electricity network for supplying energy internally of an environment (whether a private, public or industrial building) with the aim of using, where possible, all or part of the energy producible by the plant alternatively to or in supplement to the energy supplied by the traditional network. Further, the aim of the invention is to provide a photovoltaic plant of a non- fixed type (tendentially) equipped with all the devices necessary in respect of the standards relating to the connection in parallel to the public network. In particular, an aim of the present invention is to provide an auxiliary photovoltaic plant installable with extreme ease in very rapid time and removably on the existing network, should it be necessary to cover the basic absorption of energy of the users or supply a quantity of supplementary energy to cover any peaks.

These aims are fully achieved by the photovoltaic plant according to the present invention that is characterized as set down in the appended claims that follow.

Brief description of the drawings

This and other characteristics of the invention will become more apparent from the following detailed description of a preferred, non-limiting embodiment thereof, with reference to the accompanying drawings, in which:

- figure 1 is a diagram of the auxiliary photovoltaic plant of the invention in an embodiment thereof;

- figure 2 illustrates a detail in enlarged view of figure 1.

Detailed description of preferred embodiments of the invention

With reference to figure 1 , the auxiliary photovoltaic plant for generating energy comprises:

one or more generating modules (1) preferably having a low power, by way of example comprised between 200 and 350 W each;

each of these is connected, in output and by means of the related devices of an inverter (2) type which actuate transformation of the current from direct to alternating, to

a power line (3) equipped with means (4) for reversible connection to the existing electricity network (5) of an end user (6) (in the figures illustrated with a plurality of users).

Module switches (28) for each of the modules (1) are included between the inverters (2) and the network (5), the function of which is to disconnect, when necessary, the above-mentioned module (1) - network (5) connection.

In an alternative solution, the module switches (28) can be positioned upstream of the inverters (2).

The module switches (28) are preferably constituted by transistors able to open and close, modulating the power produced by the modules (1).

The existing electricity network can preferably be a part of a network of a dwelling or of a business or a like user device.

A control system (7) is connected, in output (8) and by means of a switch - disconnector (9), to the power line (3), and in input to an operator (17) of a comparator type (17).

The operator - comparator (17) is equipped with a first comparison input (10) (reference) and a second input (11) directly proportional to the value of the power absorbed by the end user.

The function of the above-mentioned operator - comparator is essential for the operation entire system, as:

- upon detecting the second input (1 ) where it is < the first input (10), the switch-disconnector (9) is operated in such a way as to disconnect, by opening, the power line (3) from the electricity network (5) and, vice versa, - upon detecting the second input (11) where it is > the first input (10), the switch-disconnector (9) is operated to close in such a way as to connect the power line (3) in supplement to the electricity network (5), augmenting by summing to the energy produced.

On a practical level, the above-illustrated generator is composed of a number n of modules (1) (with n being also = to one) up to reaching a limited total generated power, for example not greater than 1 kW.

Use thereof is exclusively correlated to the connection thereof to an electrical system supplied by a public distribution network (denoted by (P) in figure 1).

The plant of the invention is particularly destined for non-fixed applications, by way of example: on sun shade awnings including those with a sloping or adjustable-opening, supported on terraces and sundecks, in gardens and private and public outside areas of buildings, etc.

Thanks to the low installed and generatable power and for the type of application, from the point of view of regulations, the plant respects the connection standards relating to users.

In particular the connection is performed, for practical reasons, by a plug connection to be inserted directly in any fixed socket (see the larger-scale detail of figure 2) forming part of the electrical system of the building.

This connection is identifiable with the above-mentioned reversible connection means (4).

Another essential element is constituted by the above-mentioned control system (7) which is identified by a comparator (17) the two inputs of which are identifiable in the first comparison input (10) (reference) and in the second input (11) directly proportional to the absorbed energy value of the end user.

In particular the second input (11) derives from the measuring of the charge in output by the meter of the existing network (P) by means of a sensor (12) connected downstream of the meter device (PC) of the existing electricity network of the end user.

The sensor (12) will preferably be of toroidal or Hall effect type.

The current value detected by the sensor (12), suitably conditioned by the signal conditioner (40) supplied by the network (42), can:

in a first solution, be carried as an input (11) to the comparator directly through wire support communication (20), for example using the same electricity network already existing or via a dedicated line, - illustrated by a dashed line - or,

in a second solution, by a communication via wireless connection (21) - illustrated by a continuous line. The signal conditioning device (40) also communicates, via an output, with a display (41) for directly displaying the detected value.

Alternatively, the output of the signal conditioning (40) can send the data to a pc or a smartphone, denoted in all cases by reference numeral (41). To specify more clearly, the value of the first input (10) will be:

in a simpler first solution, directly settable when setting as a function of the number of modules (1) used (for example a value K = No. x 250KW), or, in a second more accurate solution, directly detectable - denoted by (30) - by the generated current that travels along the power line (3).

The function of the above-mentioned operator - comparator is essential for the operation of the entire system since it is able to disconnect the plant defined by the generator modules (1) (in all or in part) in the case where the local users (6) do not require the energy produced by the auxiliary generator of the invention and also prevents the introduction of energy produced into the public grid (this not permissible since it would defeat the entire aim of the plant as any energy introduced into the grid would not be remunerated).

The control system therefore acts by monitoring the total power (or the current) absorbed by the plant of the building - user, comparing it with the power (or the current) produced or producible by the generators (1), with the specification of never reversing the flow of power internally of (towards the) meter (PC) of the plant.

A special and qualifying characteristic of the present solution can be highlighted by the fact that the control element does not use - for example - the three elements of meter power, load power of users and power produced by the generator, but only the power of the meter which we shall term the Pgrid (denoted herein above by ( 1)).

This will be compared with the reference Pr (reference numeral (10)), in such a way that:

- Pgrid > Pr→ switches (28, 9) closed;

- Pgrid < Pr→ switches (28, 9) open. Each generator module (1) will preferably be equipped with a respective inverter device (2) and a respective ON/OFF module switch (28) (of an electromechanical or static transistor type) before associating and defining the supply line (3).

In this way the control system can act either directly on the switch (9) positioned along the line or on one or more of the above-mentioned module switches (28), in each case respecting the equation-condition mentioned in the foregoing.

Lastly the plant may be equipped with batteries for electric and/or charge regulator storage (A), positioned, as shown in the figures, downstream of the generator modules (1) that optimize the production of the generators themselves as a function of the plant load.