Electrical Performance of a Piezo-inductive Device for Energy Harvesting with Low-Frequency Vibrations

Abstract

This study presents the experimental evaluation of a piezo-inductive mechanical system for applications of energy harvesting with low-frequency vibrations. The piezo-inductive vibration energy harvester (PI-VEH) device is composed of a voice coil motor (VCM) extracted from a hard disk drive. The proposed design allows the integration of different element types as beams and masses. The dynamic excitations in the system produce a pendular motion carried out by a hybrid arm (rigid-flexible) that generates energy with the rotations (with a coil) and the beam strains (with a piezoelectric material). The electrical assessment was performed through different working modes classified as inductive, inductive with magnetic instabilities, and piezo-inductive. The instabilities in the harvester refer to external forces induced by two magnets that repel each other. The first two inductive configurations were designed as a function of three parameters (length, mass, instability angle) to debug these using the maximum output voltage. The selected experiments were conducted in a piezo-inductive configuration. The results showed two effects on the output voltage-the first one is related to a system without resonances (higher broadband), and the second effect is associated with a multi-resonant system. As a final conclusion, it is pointed out that the electrical performance can be improved with the magnetic instabilities since these considerably amplified the output voltages.Actuators 2019, 8, 55 2 of 14 applications [5]. For example, [6] show that the energy harvesting systems can feed sensor networks, since the replacement of the batteries can be very impractical due to its remote locations. For this case, the use of non-limited energy sources becomes relevant if energy harvesting technologies can capture, store, and supply the energy permanently to these sensor networks [7].Different alternatives have been proposed to use the renewable energy sources through the energy scavenging, which is defined as the process by which the energy is transformed and provided into small quantities [8]. Diverse energy sources are used for this purpose, among which are solar, wind, electromagnetic radiation, thermal, and mechanical vibrations [9], and a combination of different transduction mechanisms can be integrated in order to capture the energy from these energy sources such as magnetostrictive, piezoelectric, electromagnetic, and electrostatic. These systems are called hybrid energy harvesters (HEH), as mentioned by [10]. Vibratory energy sources have shown promissory applications in devices that demand low power consumption [11]. Since the electrical power is obtained with resonant systems that can improve its electrical performance from the design focused on the excitation frequencies [12,13]. In this context, the energy generated by mechanical vibrations could be provided from the bridges, winds, river and sea waves, human body motions, etc. For the mentioned energy sources, [14] considers high frequencies to be above 50 Hz and low frequ...

A Review of Piezoelectric Vibration Energy Harvesting with Magnetic Coupling Based on Different Structural Characteristics

“…The results showed that the magnetic plucking was more useful to use on a piezoelectric energy harvester for MEMS. The maximum peak power of 15.6 μW was obtained across a resistive load of 117210 Ω under an excitation acceleration of 1 g. Vargas and Tinoco presented a piezo-inductive device for energy harvesting [ 229 ] ( Figure 20 d). This configuration generated energy in two parts—the coil moving on the magnetic field, and a piezoelectric transducer.…”

“…( c ) An arbitrary-directional harvester (reproduced with permission from [ 227 ]; published by IOP, 2019). ( d ) The hybrid harvester (reproduced with permission from [ 229 ]; published by MDPI, 2019).…”

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