In this paper, we present a comprehensive analytical–numerical investigation of the nonlinear dynamics and bifurcation behavior of a broadband piezoelectric energy harvester (PEH) integrated with a Positive Position Feedback (PPF) control strategy. The novelty of this work lies in the development of a unified framework that captures the coupled effects of primary and internal resonances in the presence of active control. The governing nonlinear equations of motion were solved analytically using the second-order Multiple Scales Perturbation Technique (MSPT), yielding accurate approximate solutions and frequency–response relationships. The proposed approach provided a rigorous analytical treatment of the controlled nonlinear system. It revealed the underlying mechanisms governing vibration suppression and stability enhancement. Furthermore, bifurcation analysis was conducted to identify multistability, jump phenomena, and transitions between stable and unstable solutions as system and control parameters vary. The analytical predictions were validated through numerical simulations using MATLAB and MAPLE, showing excellent agreement in frequency–response curves, time histories, and phase portraits. The results demonstrated that the PPF controller significantly improves the system's dynamic performance by suppressing nonlinear oscillations, mitigating jump phenomena, reducing settling time, and stabilizing the response, leading to more stable and favorable operating regimes for effective energy harvesting. Overall, this study provides new insights into the design and control of nonlinear piezoelectric energy harvesting systems with potential applications in self-powered sensing and smart vibration control systems.