Investigation of Energy Exchange Between Coupled Electro-Mechanical Conservative Oscillators

Abstract The Internet of Things (IoT) needs to rely on efficient and sustainable power sources for its devices and ambient energy harvesting offers a promising solution. Among various energy harvesting methods, electrostatic converters, particularly those using micro-electro-mechanical systems (MEMS), are of significant interest due to their compatibility with low-frequency applications. However, the understanding of energy transfer between the mechanical and electrical domains in electrostatic harvesters is still limited. This study investigates the underlying principles governing energy conversion in idealized mechanical-electrical coupled oscillators, the building block of electrostatic harvesters. The conservative system consists of a spring-mass oscillator coupled with an inductance-capacitance circuit by a variable capacitor, where the moving mass acts as an electrode to variable capacitor. The research explores the influence of initial conditions, such as the mass position and initial charge, on energy transfer in the system. The position of mass dictates the initial energy transfer in the system. At extreme positions, energy is transferred from mechanical to electrical domains, while near the initial position (spring is unstretched), the transfer energy reverses. Similarly, the initial charge governs the speed of energy transfer in the system. These findings provide insights into optimizing energy conversion for improving the efficiency of electrostatic harvesters for IoT applications.