A wideband 2-DOF resonator for electromagnetic energy harvesting systems

Characterisation of anti-resonance in two-degree-of-freedom electromagnetic kinetic energy harvester, with modified electromagnetic model

“…Previous studies of MDOF systems (Cottone et al, 2014; Fu et al, 2014) do not capture the particular dynamics, as shown in Figure 2, and present in the experimental results. The mathematical representation of the physical system must be defined as a piecewise system, due to the potential for coupled and decoupled states.…”

“…A significant improvement has been realised in the accuracy of the model from that presented in Fu et al (2014). This is due to a more realistic model of the dry friction along the central rod.…”

“…Dry friction is modelled by the c ^ i sign ( x · i ) + c i x · i term in equations (1) and (2), which can be considered as Coulomb and viscous friction model. Friction plays a significant role in the behaviour and performance of mechanical systems (Andersson et al, 2007), and therefore a significant improvement in the previous model (Fu et al, 2014) is logical.…”

“…However, the actual mechanism of the electromagnetic energy transduction is not described in detail. This lack of clarity in the electromagnetic model is proposed as the reason why a majority of articles in the area of electromagnetic energy harvesting (Boco et al, 2015; Cottone et al, 2014; Foisal et al, 2012; Fu et al, 2014; Joon Kim et al, 2010; Mitcheson et al, 2004; Oliver and Priya, 2009; Williams and Yates, 1995; Yang et al, 2009) present Bl x · as the model of the electromagnetic transducer. Other authors (Cepnik et al, 2011; Mizuno and Chetwynd, 2003; Yang et al, 2009) have highlighted that the magnetic field due to the oscillating magnet is not constant in the coil.…”