Comparision between two stand-alone PV configurations: Series PVs versus series VSCs

Three-Level Neutral Point Clamped Inverter Fed By A Photovoltaic System Under Partial Shading

“…Switches S 1 and S 2 of the boost converters are represented by the switching states q 1 and q 2 , respectively. The load is star-connected so that the inverter model is given by: (1) where j = a, b, c. In case the load is balanced, voltage v on is given by:…”

“…Different topologies have been conceived for handling photovoltaic energy generation. Their choice depends on different criteria such as the number of available PV panels, output signal quality (voltage and current), system efficiency, and managing complexity [1]- [4]. In one of the possible solutions, two power conversion stages are provided, each one using one dc-to-dc boost converter between the PV module and the dc-bus.…”

“…As a consequence, when the PV Manuscript received 19/03/2016; first revision 07/05/2016; accepted for publication 04/07/2016, by recommendation of Editor Marcelo Cabral Cavalcanti. output voltage is stable, the use of the NPC inverter is attractive [9], [10]. However, when there is partial shading the capacitor voltage balance is not anymore guaranteed and provokes loss of quality in the output signals [1]. A dc-link control to overcome that problem was introduced in [11].…”