Dual DC-DC converter and monitoring interface for asymmetrical string inverters

This paper proposes monitoring of the dual dc-dc converters that independently operate of each other in the same topology (Buck-Boost). The dual converter structure is proposed to implement asymmetrical string inverter that is intended to be used variously arranged PV strings. The converters are operated by independently running MPPT algorithms. The converters are supplied by programmed dc sources emulating freely arranged solar arrays, and different loads are connected to each converter output. The converters allow using independent power sources like hybrid power techniques owing to these features. Current and voltage sensors measure the output powers of each converter, where the obtained values are evaluated by P&O algorithm on MCU and the PWM signals are generated. At the same time, obtained values are transmitted to computer by a microcontroller on optically isolated UART to USB unit. The received values are saved in a database to enable historical and instant analyse capability of the converters.