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Microinverters are devices from the MLPE (module level power electronics) family. In direct translation into Portuguese, MLPE means “module level power electronics”. Power electronics is the area of electrical engineering that develops electronic power converters (such as inverters, microinverters and other things), while the term “module level” refers to the fact that microinverters are always installed close to the photovoltaic modules. From the point of view of the organization of the photovoltaic system, the main difference between microinverters and conventional inverters is their distance from the photovoltaic modules and from the connection point to the alternating current grid. Conventional inverters are installed far from the modules and require a long direct current cabling, while they are closer to the alternating current grid. Microinverters, on the other hand, are installed close to the modules and do not require additional direct current cables, other than those that are already supplied with the photovoltaic modules. In addition to not requiring direct current cabling, microinverters have their alternating current outputs connected directly to the installation's AC protection panel, via a trunk cable, without the need for a stringbox. Originally, microinverters were intended for use with just one photovoltaic module. With the evolution of technology, microinverters have become larger. Current microinverters can accommodate two to four photovoltaic modules, but they still maintain their compact nature, which allows them to be installed close to the modules (usually underneath the modules, attached to the fixing structures or to the module frames). The microinverters are connected to the electrical grid via a trunk cable. The figure below illustrates two possible strategies for this connection. In the first strategy, we find what can be called a standard trunk cable (type 1) – which is a continuous cable with connections through which the branches to the microinverters are created. In the second strategy, also illustrated in the figure below, the microinverters are connected to each other, as in a series connection, and the microinverter at the end receives the cable that will take the circuit to the connection point with the electrical grid. In any strategy adopted, the microinverters are always connected in parallel, as shown in the multi-wire electrical diagram – also illustrated in the figure below. The figure below illustrates a system based on microinverters with inputs for two modules. The modules are connected to the DC inputs of the microinverters. In turn, the microinverters are connected to each other and then connected to the AC connection panel of the installation. In this case, a system with a type 2 trunk cable is illustrated.

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