Do We Really Need Complicated Solar Energy Harvesting Circuits for Low Cost Sensor Nodes?

Existing solar energy harvesting structures with maximum power point tracking capability are typically a bit complicated and expensive for low cost sensor nodes, which makes them unsuitable for large-scale deployments of wireless sensor networks. In this paper, a voltage matching method for suboptimal solar energy harvesting is proposed. By matching the working voltage ranges of rechargeable batteries with the maximum power point voltages of solar panels, the output voltages of solar panels could be clamped around the maximum power point only using a simple and cheap diode. In this way, suboptimal but efficient enough solar energy harvesting could be achieved. Experimental results show that compared with existing structures, energy harvesting efficiency of the proposed method only reduces by 2.3%~18.8%.