Quasi-MPPT Control for Integrating Multiple Energy Harvesters of Different Characteristics

This paper proposes a quasi-MPPT (maximum power point tracking) control for integrating multiple energy harvesters of different characteristics. Energy harvesting (EH) technology is a promising technology and is expected to be widely used in various fields. However, the amount of the harvested power is inherently limited and strongly depends on the weather and other conditions. Therefore, multiple energy harvesters are often integrated to increase total harvested energy. In the case of integrating multiple energy harvesters of different characteristics, the control tends to be complicated due to the different characteristics of the energy harvesters. The proposed quasi-MPPT control enables the multiple energy harvesters to work near their MPP voltages by referring to the command voltages derived from preliminary identification of the energy harvesters and measurement of the open-circuit voltages. It achieves harvesting of approximately maximum powers of the multiple energy harvesters by a simple control strategy using a power management circuit. The effectiveness is validated by using an experimental system that consists of photovoltaic (PV) and thermoelectric (TE) energy harvesters.