A novel method of Peak Detecting for Self-Powered Synchronized Switch Harvesting on Inductance Using Reed Switch

Ya Shan Shih (1) , Dejan Vasic (2) , Wen Jong Wu (3)

1 SATIE - Systèmes et Applications des Technologies de l'Information et de l'Energie
2 SATIE-EPI - Electronique de Puissance et Intégration
3 NTU - National Taiwan University [Taiwan]

Synchronized switch harvesting on inductance (SSHI) has long been studied so as to enhance the power gain of piezoelectric energy harvesting. The idea of the SSHI is to launch an inductance to the circuit on the peak of the waveform so that the inductance resonates with the clamped capacitance of the piezoelectric patch. The resonance causes a rapid inversion of the voltage, which then the switch is turned off, halting the voltage on its inverted state. This technique enhances the power output when appropriate parameters are met. It is notable that detecting the optimal switching time is inevitable in this technique. In spite of the several simple ways already in use, such as voltage peak detection using bipolar transistor or zero velocity crossing detection, these methods requires a considerable amount of energy in respect to the harvested energy. On account of the harvesting efficiency, which the total harvested amount is from the scale of nano-watts to micro-watts, it is mostly impractical to introduce techniques or elements that requires external power sources or extra power consumptions when it comes to a high portion of energy loss considering the limited amount of energy harvested. Thereby, researchers have endeavored to realize the peak detecting in various mechanical and electrical methods so that little or few energies are required. In this work, we propose a new hybrid peak detecting technique utilizing reed switch, which is a non-contact mechanical method that requires little energy consumption. Using a pair of magnets as the proof mass, not only the resonance frequency can be easily tuned, it could also serve as the non-contact control of the reed switch. However, mechanical chattering, a phenomena which exists in all the mechanical switches, is yet to be solved. The phenomena of chattering is the contact bounce when the two metal parts of the switch strike together. In attribution to the elasticity and momentum, the two parts bounces off and on in the transient state for a short moment until settling down to stable. Experiments were conducted to find the losses due to the chatter, and to also find the performance of the new structure. Results showed a promising outcome of 88.9% in comparison to the external powered SSHI. The following sections are divided in to 5 parts: introduction to SSHI and some switching techniques, experiment setup, experiment results, discussion, and conclusion along with some plans of future work. 1. Introduction Synchronized switching on inductance (SSHI) is a technique to improve the harvested power of the piezoelectric energy harvester, proposed by Lefeuvre et al during 2004 [1-3] originally introduced as synchronized switch damping (SSD) for vibration control [4]. With low electro-mechanical coupling systems, it was discovered that this approach could increase the harvested power by 400% in comparison to the standard circuit of a rectifier consisting four diodes. By applying a non-linear processing electronic circuit of a switch and an inductor to the standard rectifier, the switch was turned on and off on the maximum and the minimum of the mechanical displacement. On the triggering moment, the LC resonance of the inductance and the parasitic capacitance of the piezoelectric patch, was launched. This quick

Domaines: Energie électrique

Ya Shan Shih, Dejan Vasic, Wen Jong Wu. A novel method of Peak Detecting for Self-Powered Synchronized Switch Harvesting on Inductance Using Reed Switch. ICAST 2015, Oct 2015, Kobe, Japan. ⟨hal-01697553⟩