Analytical and Experimental Investigations on Low-Frequency Simultaneous Vibration Isolation and Energy Harvesting Using Magnetic Rings

Simultaneous vibration isolation and energy harvesting (SVIEH) are becoming increasingly attractive in suspension systems. However, there is a conflict between low natural frequency and large loading capacity. In addition, the energy harvesting performance is always limited by maintaining the vibration isolation performance in most existing studies. Therefore, how to enhance vibration energy harvesting while satisfying vibration isolation is still a challenge. In this paper, a pair of magnetic rings is used to generate quasi-zero stiffness (QZS) for dealing with the conflict between large loading capacity and low natural frequency, and a Halbach magnetic ring is presented to enhance the energy harvesting performance. Based on them, a novel low-frequency QZS-based SVIEH (QZS-SVIEH) structure is proposed. Firstly, the structural condition of generating QZS is derived. Next the electro-mechanical coupling equations of the QZS-SVIEH system are built and solved by using the harmonic balance method (HBM), which is also verified by the Runge-Kutta method. Then the displacement transmissibility and output power are defined as the two performance indicators for vibration isolation and energy harvesting, respectively. The effects of electrical and mechanical parameters on the two performance indicators are studied in detail. Finally, the prototype of the proposed QZS-SVIEH structure is constructed for experimental testing. The experimental results show that the QZS-SVIEH can effectively suppress vibrations with frequencies above 7.2Hz and generate the peak power of 0.8W under the excitation of acceleration 1.5g and frequency 10Hz.