Smart PV modules — Design considerations

This paper explores the design of a smart photovoltaic (PV) module- a PV module in which PV cells in close proximity are electrically grouped to form a pixel and are connected to dc-dc converter blocks which reside embedded in the back pane of the module. An auto-connected flyback converter topology processing less than full power is used to provide high gain and perform maximum power point tracking (MPPT). These dc-dc converters interface with cascaded H-bridge inverter modules operating on feed forward control for dc-link voltage ripple rejection. The proposed configuration is capable of producing 120V/ 240V AC voltage. The PV module now becomes a smart AC module by virtue of embedded intelligence to selectively actuate the individual dc-dc converters and control the output AC voltages directly, thus becoming a true plug and power energy system. Such a concept is ideal for curved surfaces such as building integrated PV (BIPV) system applications where gradients of insolation and temperature cause not only variations from PV module-to-PV module but from group-to-group of cells within the module itself. A detailed analysis along with simulation and experimental results confirm the feasibility of the proposed concept.