Monitoring of actuation conditions in a micro-turbo-generator

This paper presents the theory and implementation of an integrated sensing technique for the real-time measurement of applied actuation conditions in a micro-turbo-generator. The device is composed of a microturbine rotor with magnetic components and a stator with planar coils for electromagnetic induction. While the rotor is actuated with pressurized nitrogen, the induced voltages are extracted to generate and deliver electrical power as well as to monitor the pneumatic actuation parameters. It is demonstrated that the rotor speed, applied gas flow rate, and pressure show repeatable high linearity with respect to voltage frequency and amplitude in different devices. Sensitivity values of 83 Hz/krpm, 140 Hz/slm, and 1428 Hz/psi together with R² values larger than 0.97 are achieved. The integrated sensing technique presented in this paper will eliminate the need for external sensing components in continuous device screening, and lead to closed-loop control for autonomous tuning of desired operating conditions in rotary microgenerators.