Photovoltaic-battery powered DC Bus system for common portable electronic devices

Renewable energy sources based on photovoltaic along with battery-based energy storage necessitate power conditioning to meet load requirements and/or be connected to the electrical grid. The power conditioning is achieved via a DC-DC converter and a DC-AC inverter stages to produce the desired AC source. This is also the case even when the load is of DC type such as the typical electronic devices which require AC adaptors to be powered from the AC mains. The paper presents a hybrid photovoltaic-battery powered DC bus system that eliminates the DC-AC conversion stage resulting in lower cost and improved efficiency. It is also shown experimentally that the AC adaptors associated with the various commonly used electronic devices can be reused with the proposed system and in some cases offer higher operating efficiencies when powered from a DC bus instead. A novel high-gain modified boost converter is also introduced with several times higher voltage conversion ratio than the conventional boost converter topology. This arrangement results in higher DC bus levels and lower cable conduction losses. Moreover, the voltage stress on the modified boost converter power switch is within half the output voltage. Experimental results taken from a laboratory prototype are presented to confirm the effectiveness of the proposed approach.