Toru Ikegame

Sensor-less parameter estimation of electromagnetic transducer and experimental verification

In this paper, a new sensor-less parameter estimation method is proposed for electromagnetic shunt damping. The purpose is to estimate parameters of an electromagnetic transducer and a vibrating structure. The frequency domain measurements of an electrical admittance are only supposed to be available but any other sensor measurements are not; therefore, the estimation problem is nontrivial. Two types of numerical optimization, a linear optimization to select an initial seed and a nonlinear optimization to determine a final estimate, are presented. The effectiveness of the method is demonstrated by vibration control experiments as well as parameter estimation experiments.

Charging efficiency of a passively switched flyback converter for dielectric elastomer generator

This paper shows an experimental demonstration of a high efficiency step-down circuit for a dielectric elastomer generator. The step-down circuit, consisting of a surge arrester and a transformer, is classified as a passively-switched flyback converter and can transfer energy efficiently. In the experiments, the efficiency of the step-down circuit is nearly 100 times higher than that of a Zener diode, which is used for the simplest step-down conversion. Also, we discovered that the harvested power and the efficiency are improved better if the breakdown voltage of the surge arrester is selected to be higher. Finally, the wireless transmission of a microprocessor is demonstrated using the step-down circuit connected to a dielectric elastomer generator and a self-priming circuit.

Development of an energy harvesting circuit with photo MOSFET and Arduino for linear electromagnetic transducers

An energy harvesting circuit with an isolated step-up chopper circuit and an Arduino is newly developed for electromagnetic transducers including voice coil motors. The isolated step-up chopper circuit is implemented by a photo MOSFET. The optimal duty ratio is computed by a DSP and the photo MOSFET is controlled by the Arduino. The measured charged voltage shows an agreement with the prediction of the previously studied results.

Energy harvesting by dielectric elastomer generator and self-priming circuit: verification by radio transmission

This paper discusses energy harvesting and its application using dielectric elastomer and self-priming circuit. With the self-priming circuit attached to the dielectric elastomer, the generated voltage increases exponentially according to the variation of the capacitance caused by applied deformation to the elastomer. Two-stage self-priming circuit is selected for optimal harvesting. The self-priming harvesting technique is able to increase the voltage of the dielectric elastomer from a few volts to kV order, however in this paper the generated voltage is limited up to 1kV in order to avoid the destruction of the dielectric elastomer. The ability of energy harvesting using dielectric elastomer and self-priming circuit is confirmed by both numerical simulation and experiments. In the experiment, the dielectric elastomer is deformed by an electric motor, and the harvested energy is stored to a charging capacitor through Zener diodes. A low-power microcomputer which has a radio transmitter is connected to the charging capacitor for the application example. The experimental results show that the temperature data can be transmitted only by the harvested energy. In addition, the efficiency of the energy harvesting is calculated by comparing the generated power with the charged power.