Synergetic enhancement of bi-stable piezoelectric energy harvester using in-plane lateral constraint and magnet-spring oscillator

To enhance the energy generation capability of bi-stable piezoelectric energy harvesters (PEHs) for sustainably powering low-power electronic devices, a synergetic enhancement strategy combining an in-plane lateral constraint (ILC) and a magnet-spring oscillator (MSO) is proposed. Unlike conventional axial ILC configurations, the width-direction ILC applied at the beam tips induces coupled bending-torsion deformation in both the length and width directions, resulting in a discontinuous and tunable asymmetric bi-stable restoring force, which is fundamentally different from the continuous bi-stable nonlinear force in existing PEHs. The MSO provides dynamic potential modulation to reduce the potential barrier and achieve high-orbit dynamic response. The synergistic interaction between these two mechanisms creates a continuous double-resonance response, which significantly enhances the dynamic performance. With this synergetic enhancement strategy, a novel bi-stable PEH integrated with ILC and MSO is developed, and the nonlinear electromechanical model is established, and its dynamic responses are then theoretically investigated and experimentally validated. The experimental results indicate that, under A = 15 m/s², R = 1 MΩ, d = 23 mm, k = 50 N/m, and ∆ = 2.5 mm, the proposed PEH achieves a normalized power density (NPD) of 3.893 mW·cm⁻³·g⁻² and an effective bandwidth of 5.1 Hz, representing improvements of 39.2% and 59.4%, respectively, over a Normal PEH. Further application examples show that the proposed bi-stable PEH fully meets the requirements of sustainable power supply for low-power electronic devices.