Charge Redistribution-Aware Power Management for Supercapacitor-Operated Wireless Sensor Networks

Supercapacitors (SCs) have been used in energy harvesting wireless sensor networks (WSNs) to relieve the life cycle limitations that most traditional rechargeable storage devices suffer from. SC-operated WSNs present new challenges for power management due to its high self-discharge and charge redistribution. Power management algorithms have been developed to reduce self-discharge loss, but few studies have focused on charge redistribution loss in SC-operated WSNs. In this paper, we investigate how SC charge redistribution affects power management in long-term WSN applications, and develop a practical power manager to reduce redistribution loss by scheduling the workload in a way that maintains a relatively balanced voltage between the main branch and the delayed branch of an SC. The manager has low computational complexity and yields considerably smaller charge redistribution loss than other power managers.