A gyroscopic power generator that generates a power of 1.8 W is developed with a rotor of 100 mm diameter and 500 rpm spin speed. In conventional vibration generators, which use simple vibrations of an inner pendulum, the output power has been less than 60 mW. Gyroscopic generators increase the inertial force by rotating the pendulum at a high speed and generate about 50 times greater power than the conventional ones. However, wearable gyro generators that operate under arbitrary vibrations have not been realized because the gyro torque and the electromechanical transformation efficiency are greatly reduced by miniaturization. In this study, first, a theoretical model is developed to clarify the basic characteristics of the generator. Next, a desktop-sized generator that works under any vibration is developed using highly precise motors and gears determined by the theory; the optimum rotor, motor, and gear parameters are decided according to the approximate solution of the mathematical model. Next, mechanical and electrical characteristics are measured to show the validity of the theory. Finally, a wearable test device is produced by modifying a 2.52" hard disk drive (HDD) to show the possibility of obtaining a practical generator.
A motor-driven gyroscopic generator was developed that self-accelerates by power feedback. In a previous report, power generation of 1.8 W was confirmed, but an external power source was used to drive the spin motor. In this research, a method is presented to apply the power generated from the precession movement to the spin motor. It enables not only eliminating the power source but also accelerates the spin velocity. To achieve acceleration, however, the feedback circuit must boost the generated voltage since the counter voltage of the spin motor also increases with its velocity. Also, there is an optimum boosting rate that depends on the spin velocity. In this paper, first, a circuit equivalent to the gyro-generator system is presented and the coil resistance of the generator is shown to limit the highest boosting rate. Next, the rotor accelerating characteristics of four boosting circuits are compared. Electrical boosting is shown to have the same effect as mechanical impedance control. A numerical simulation is conducted and the power acceleration by boosting is also verified. Finally, a prototype generator is developed. The validity of theoretical results is verified and an output power of 0.1 W is obtained.
A gyroscopic power generator that generates 1.8 W by using a rotor of 100 mm diameter spinning at 500 rpm is developed. In conventional vibrational generators, which use simple vibrations of a inner pendulum, the output power has been less than 10 mW. Gyroscopic generators increase the inertial force by rotating the pendulum at high speed and generate about 100 times greater power than the conventional ones. However, gyro generators have not been able to operate under arbitrary vibrations at wearable sizes because they are unstable and easily stall by disturbances, and the gyro torque and the electromechanical transformation efficiency rapidly decrease by miniaturization. In this paper, first, a theoretical model is developed to clarify the basic characteristics of the generator. Next, a desktop-sized generator that works under any vibration is developed using highly precise motors and gears determined by the theory. Next, mechanical and electrical characteristics are measured to show the validity of the theory. Finally, the performance of wearable-sized generators is predicted to show the generators that have the same device size and rotor spinning speed as those of 2.5” and 3.5” HDD’s generate 0.74 W and 1.84 W, respectively.
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