Modular photovoltaic solar inverter

Abstract

The present invention relates to a modular solar photovoltaic inverter where by reducing the size of the filtering module and reducing the number of components, it reduces the size of the solar inverter compared to the state of the art; and with the configuration of the power modules, it generates channels that allow the passage of air from the cooling module, obtaining a modular photovoltaic solar inverter that improves the dimensions, weight, maintenance, cooling and safety with respect to those known up until now.

Claims

1. A modular photovoltaic solar inverter comprising: a plurality of power modules that convert a direct current (DC) to an alternating current (AC), a DC bus that connects all the inputs of the power modules to a photovoltaic field through a connection/disconnection device, wherein each power module in turn comprises a power cell and a filtering module linked to an output of the power cell to adapt the electrical characteristics of the alternating current (AC), an alternating current (AC) bus that connects the output of each power module to an electrical network, wherein the power modules are configured to form groups of two power modules facing each other, and each group of two power modules is electrically linked in parallel to the other groups of two power modules, wherein the filtering module is an LLC filter comprising: a first inductance for each output phase of each power module, wherein the first inductances of each group of two power modules are coupled together in their respective phases, a capacitor connected in parallel to the first inductances, and a second inductance linked in series to the capacitor.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To complement the description that is being made and for the purpose of helping to better understand the features of the invention according to a preferred practical embodiment thereof, in which a set of drawings depicting the following in an illustrative and non-limiting manner is attached as an integral part of said description:

(2) FIG. 1 shows a schematic view of a solar inverter according to the state of the art.

(3) FIG. 2 shows a schematic view of the modular photovoltaic solar inverter of the present invention.

(4) FIG. 3 shows a perspective view of the modular photovoltaic solar inverter of the present invention.

(5) FIGS. 4A, 4B, 4C and 4D all show perspective views of the extraction module being extracted from the modular photovoltaic solar inverter of the present invention in two stages of said extraction.

DETAILED DESCRIPTION OF THE INVENTION

(6) In a preferred embodiment, as shown in FIGS. 2, 4A, 4B, 4C and 4D, the modular photovoltaic solar inverter (1) is arranged in a container (10), wherein the modular photovoltaic solar inverter (1) in turn comprises: a plurality of power modules (2), each of which comprises a power cell (6) and a filtering module (3). The modular photovoltaic solar inverter (1) further comprises a cooling module (4) and a transformer module (5).

(7) The container (10), comprising a first and a second sealed compartment preferably with an IP54/IP65 protection level separating the power modules (2) from the transformer module (5), is configured to protect the modules (2, 3, 4, 5) from rain and high and low temperatures (typically between −35° C. and 60° C.). Additionally, the container (10) comprises a plurality of doors to allow temporary access to the different modules (2, 3, 4, 5), support structures configured to horizontally support and guide the power modules (2), and first and second hooks to enable the coupling of an extraction module (12).

(8) Specifically, the plurality of power modules (2) are configured for forming groups (17) of two power modules (2), each group comprises the filtering module (3) and two power cells (6), which are configured to convert direct current (DC) from photovoltaic panels to a modulated (PWM) alternating current (AC). More specifically, the two power cells (6) are facing each other, and electrically linked in parallel to the next power module (2). Thus, each group (17) of two power modules (2) is electrically linked in parallel to each other group (17) of two power modules (2), as shown in FIG. 2.

(9) Further, as shown in FIG. 2, a DC bus connects all the inputs of the power modules (2) to a photovoltaic field through a connection/disconnection device (16).

(10) Additionally, as shown in FIGS. 4A, 4B, 4C and 4D, each power inverter (6) comprises two input plates (7A) configured to connect to the DC bus produced by the photovoltaic panels and three output plates (7B) connected to the AC bus. Each power cell (6) on the side thereof also comprises a groove configured to be coupled to the support structures of the container (10) and in case of extraction/introduction with guide elements, each power cell (6) thus being installable and removable in an assisted manner by these elements and therefore feasible by a single operator.

(11) Preferably, these plates (7A, 7B) are configured to be removably linked to the power module (2), for example by means of the use of screws, without the need for any other electrical connection or mechanical fastening.

(12) Furthermore, the filtering module (3) is an LLC filter comprising: a first inductance for each output phase of each power module, wherein the first inductances of each group of two power modules (2) are coupled together in their respective phases, a capacitor connected in parallel to the first inductances, and a second inductance linked in series to the capacitor.

(13) Preferably, the input of the transformer module (5) is linked to the output of the LLC filter and the output of the transformer module (5) is configured to connect to the electrical network.

(14) Moreover, the cooling module (4), as shown in FIGS. 3 and 4A, 4B, 4C and 4D, is configured to reduce the temperature of the power modules (2) and the transformer module (5) and comprises a first and a second ventilation circuit that are independent from each other, and wherein each of them comprises: a centrifugal fan (8) configured to drive pre-filtered air from the base of the container (10), at least one channel (9), installed in the base of the compartment and linked to the centrifugal fan (8) thereof, extraction slots (11), installed in the roof of the compartment that enable the pre-filtered air to circulate from the base of the compartment to the outside and cool the power modules (2) by means of the first circuit and the transformer module (5) by means of the second circuit.

(15) Lastly, as shown in FIGS. 4A, 4B, 4C and 4D, the solar inverter comprises an extraction module (12) that can be coupled in a door of the container (10) that provides access to one of the power modules (2). Specifically, this extraction module (12) is configured so that a single operator can extract and replace the entire power cell (6), by coupling/uncoupling the plates (7A, 7B) when the power cell (6) is damaged. In this way, the time during which the solar inverter (1) is stopped for maintenance reasons is reduced.

(16) More specifically, as shown in FIGS. 4A, 4B, 4C and 4D, the extraction module (12) comprises: a pulley system (15), a guide element (13) horizontally coupled to first hooks installed on the side of the door frame of the container (10) that provides access to the power cell (6), wherein once the guide element (13) is installed, it is aligned with the support structures configured to horizontally support and guide the power cell (6) to enable the horizontal extraction/insertion of the power cell (6), and a support element (14) that can be coupled to second hooks installed in the upper portion of the door frame of the container (10) that provides access to the power cell (6), wherein once installed it is linked to the pulley system (15) which in turn is linked to the power cell (6), enabling the power cell (6) to be removed or installed to be vertically moved by a single operator.
By way of example, as shown in FIGS. 4A, 4B, 4C and 4D, in order to change a power cell (6), the following steps are followed: a) open the door of the container (10) that provides access to the power cell (6), b) disconnect the plates (7A, 7B), c) place the guide element (13) on the side of the door frame, such that it is aligned with the support structures, d) place the support element (14) in the upper portion of the door frame, e) extract the entire power cell (6) horizontally following first the support structures and then the guide element (13) as shown in FIG. 4D, f) link the pulley system (15) to the power cell (6) and the support element (14), g) vertically move, by means of the pulley system (15), the power cell (6) until it is resting on the ground, as shown in FIG. 4G, h) replace the power cell (6), and i) repeat the previous steps in reverse to install the new power cell (6).

(17) It must be noted that, due to the high weight of each power cell (6), once they have been positioned on the ground they must be moved with a hydraulic forklift or similar means. Despite this, the extraction module (12) enables the entire process to be carried out by a single operator.