AN INTEGRATED SIMULTANEOUS THERMAL AND RF ENERGY HARVESTING SYSTEM FOR WIRELESS SENSOR NETWORKS
Ahmed Abdulraouf Awad Ahmed Helaly;
Abstract
Abstract
This work presents an integrated simultaneous thermal/RF energy harvesting system that is suitable for low power wireless sensor networks. The system has the ability to combine harvested energy from both DC and AC sources at the same time and provide a regulated output voltage of 1.75V feeding a current load from 150µA to 770µA. The system consists of a 5-stage Pelliconi charge pump used to boost the thermal DC voltage to a higher level forming the DC-path of the harvester. On the other side, the received RF signal passes through a matching network to match the input impedance of the AC-path to the antenna impedance. The generated voltage from the matching network undergoes an RF-DC conversion using a rectifier which is also used to combine the energy from the 2 sources and produce the final output voltage.
A triple mode maximum power point tracking (MPPT) algorithm is implemented to achieve the best possible efficiency at different source and load conditions. The three reconfigurable parameters in the system are the number of stages of the DC path, the frequency driving the charge pump, and the capacitors of the matching network in the RF-path. The number of stages is adjusted to reach the highest possible output voltage, while the frequency is tuned to reach the maximum power transfer condition making the input resistance of the charge pump equal to the DC source resistance. Finally, the capacitors of the matching network are chosen to provide good matching for the received RF signal at wide range of power levels.
The energy harvester also enables the storage of extra power by charging a superca- pacitor in order to use it during power shortage periods. The supercapacitor is charged using a voltage doubler that has an output of 3.5V. The system is implemented in a 180 nm CMOS technology and utilizes a total on-chip capacitance of 2.4 nF. Simulations show that the overall end-to-end efficiency of the system reaches a maximum of 60.5% at an input thermal voltage of 350mV and an RF input power of -8 dBm.
This work presents an integrated simultaneous thermal/RF energy harvesting system that is suitable for low power wireless sensor networks. The system has the ability to combine harvested energy from both DC and AC sources at the same time and provide a regulated output voltage of 1.75V feeding a current load from 150µA to 770µA. The system consists of a 5-stage Pelliconi charge pump used to boost the thermal DC voltage to a higher level forming the DC-path of the harvester. On the other side, the received RF signal passes through a matching network to match the input impedance of the AC-path to the antenna impedance. The generated voltage from the matching network undergoes an RF-DC conversion using a rectifier which is also used to combine the energy from the 2 sources and produce the final output voltage.
A triple mode maximum power point tracking (MPPT) algorithm is implemented to achieve the best possible efficiency at different source and load conditions. The three reconfigurable parameters in the system are the number of stages of the DC path, the frequency driving the charge pump, and the capacitors of the matching network in the RF-path. The number of stages is adjusted to reach the highest possible output voltage, while the frequency is tuned to reach the maximum power transfer condition making the input resistance of the charge pump equal to the DC source resistance. Finally, the capacitors of the matching network are chosen to provide good matching for the received RF signal at wide range of power levels.
The energy harvester also enables the storage of extra power by charging a superca- pacitor in order to use it during power shortage periods. The supercapacitor is charged using a voltage doubler that has an output of 3.5V. The system is implemented in a 180 nm CMOS technology and utilizes a total on-chip capacitance of 2.4 nF. Simulations show that the overall end-to-end efficiency of the system reaches a maximum of 60.5% at an input thermal voltage of 350mV and an RF input power of -8 dBm.
Other data
| Title | AN INTEGRATED SIMULTANEOUS THERMAL AND RF ENERGY HARVESTING SYSTEM FOR WIRELESS SENSOR NETWORKS | Other Titles | نظام حصاد متكامل للطاقة من مصدر حراري و مصدر تردد لاسلكي بشكل متزامن لشبكات المستشعرات اللاسلكية | Authors | Ahmed Abdulraouf Awad Ahmed Helaly | Issue Date | 2022 |
Attached Files
| File | Size | Format | |
|---|---|---|---|
| BB14013.pdf | 1.22 MB | Adobe PDF | View/Open |
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