A Compact Energy Transducer for Power Generation From Respiration

This paper reports a compact magnetic transducer developed for generating electrical power from respiration. The device incorporates a side-drive turbine rotor with embedded permanent magnets and two stators, integrated into a poly(methyl methacrylate) (PMMA) package for actuation. The novelty and advantage of the design lies in almost full use of the available turbine volume together with two stators for both mechanical and electrical transduction, which leads to high rotational speeds and high voltage generation at low flow rates. A variety of turbine and stator designs were developed. In the best-performing design, the turbine reached 10 krpm rotational speed at 16 lpm flow rate and 74 mbar pressure drop. The open circuit voltage and output electrical power at this speed were measured to be 2.75 V and 0.06 mW on a matched resistive load, respectively. When operated at 10 krpm for 30 s, the device was able to store 1.28 mJ on a 1 mF capacitor. Tests at higher flow rates showed that the turbine can reach 30 krpm, leading to 8.14 V at the stator terminals and 0.51 mW output power. The results demonstrate the feasibility of this device to generate power from respiration, and its potential to be used in portable electronic devices.