<p>This study conducts a comprehensive dynamic analysis of a spring-cam coupled bistable piezoelectric energy harvester (PEH) system from a global perspective. The nonlinear restoring forces and dual potential well characteristics of the energy harvesting system are shown to be systematically tunable by parametrically adjusting the distance between the vertex of the programmable cam raceway. Through utilizing the extended averaging technique, both intra-well and inter-well resonant behaviors under varying geometric configurations are investigated, accompanied by comparative evaluation of respective voltage generation capabilities. Subsequent application of the Melnikov method enables theoretical prediction of critical thresholds of the base excitation for chaotic oscillations. Numerical simulations demonstrate great consistency with analytical predictions, thereby validating the proposed methodology. The evolutionary patterns of coexisting attractors and associated basins of attraction are depicted under the progressive intensification of the base excitation. The investigation reveals that minimal inter-vertex spacing configuration achieves optimal low-amplitude operational performance, whereas maximal spacing demonstrates superior energy conversion efficiency under strong excitation conditions. And the escalation of the base excitation sequentially induces high-output inter-well resonance followed by chaotic oscillations. The energy harvesting system also exhibits sensitive dependence on initial conditions such as fractalized basins of attraction and rare attractors.</p>