9 Solar Module Technology
235
Fig. 9.10 Two encapsulated solar cells: a c-Si solar cells with 2BBs and ribbons (left), and b busbarless solar cell with no ribbons and with smart-wire technology (right)
potential at the cell level. Additionally, the use of multi-wire concepts, may lead to
a considerable reduction of the sensitivity of cell/module performance to cell cracks
or breakage, thereby increasing the durability of the modules (Fig. 9.10).
9.2.3.4 Modules with Integrated Inverters (Micro-inverters)
In general, strings of multiple solar PV modules are connected to an inverter, which
converts direct current generated by the module to alternating current (i.e. a DC/AC
converter—see Chap. 12). Particularly in the USA, and for some specific applications
(such as small-scale installations in buildings) there is a tendency to integrate the
Inverters, in the form of micro-inverters, directly into the module. With a microinverter a single panel can feed its output directly to the grid. Micro-inverters can be
installed adjacent to a module (attached to the frame or replacing the junction box)
or integrated directly into the module.
The main advantage of using micro-inverters is that they electrically isolate the
modules from each other, so that in the case of module failure or shading, the output
of the full string is affected only in a limited manner.
With a conventional string or central inverter, in fact, the complete or partial
shading of a single panel may reduce the output of the full string to zero, with
a considerable impact on the overall plant performance. For this reason, microinverters may be very beneficial in solar plants that are affected by persistent or
frequent shading. As for example in the built environment, where the presence of
several objects (antennas, chimneys, adjacent buildings, etc.) can cast shadows on
the solar plant.
Compared to conventional inverters and electrical layouts, the use of microinverters requires a higher capital expenditure per watt-peak. Service and maintenance (including replacement costs) may also be higher.
235
Fig. 9.10 Two encapsulated solar cells: a c-Si solar cells with 2BBs and ribbons (left), and b busbarless solar cell with no ribbons and with smart-wire technology (right)
potential at the cell level. Additionally, the use of multi-wire concepts, may lead to
a considerable reduction of the sensitivity of cell/module performance to cell cracks
or breakage, thereby increasing the durability of the modules (Fig. 9.10).
9.2.3.4 Modules with Integrated Inverters (Micro-inverters)
In general, strings of multiple solar PV modules are connected to an inverter, which
converts direct current generated by the module to alternating current (i.e. a DC/AC
converter—see Chap. 12). Particularly in the USA, and for some specific applications
(such as small-scale installations in buildings) there is a tendency to integrate the
Inverters, in the form of micro-inverters, directly into the module. With a microinverter a single panel can feed its output directly to the grid. Micro-inverters can be
installed adjacent to a module (attached to the frame or replacing the junction box)
or integrated directly into the module.
The main advantage of using micro-inverters is that they electrically isolate the
modules from each other, so that in the case of module failure or shading, the output
of the full string is affected only in a limited manner.
With a conventional string or central inverter, in fact, the complete or partial
shading of a single panel may reduce the output of the full string to zero, with
a considerable impact on the overall plant performance. For this reason, microinverters may be very beneficial in solar plants that are affected by persistent or
frequent shading. As for example in the built environment, where the presence of
several objects (antennas, chimneys, adjacent buildings, etc.) can cast shadows on
the solar plant.
Compared to conventional inverters and electrical layouts, the use of microinverters requires a higher capital expenditure per watt-peak. Service and maintenance (including replacement costs) may also be higher.