Background <p>Conventional energy harvesters often face limitations such as complex potential functions and inflexible, nonintuitive parameter adjustments. Additionally, structural risks arising from large-amplitude vibrations remain a significant challenge in maintaining multi-stable characteristics for efficient energy harvesting.</p> Methods <p>This study investigates a novel piecewise stiffness quad-stable nonlinear piezoelectric energy harvesting system featuring a programmable potential function and a flexible limiter design. A physical and mathematical model of the system is established. The electromechanically coupled system is equivalently decoupled using a generalized harmonic transformation, and analytical solutions for the stationary probability response and average output power are derived via an energy-dependent stochastic averaging method.</p> Results <p>The analytical results show excellent agreement with Monte Carlo simulations. Parametric analysis demonstrates that the flexible limiter effectively reduces the vibration range of the magnet, thereby mitigating the risk of damage. By adjusting potential function parameters, bifurcation behaviors—transitioning the system from quad-stable to tri-stable or bi-stable states—can be achieved. The results indicate that both output power and transition rate increase with higher noise intensity. Furthermore, under weak excitation, the quad-stable configuration exhibits superior energy harvesting efficiency compared to the tri-stable structure.</p> Conclusions <p>The proposed system effectively suppresses structural risks while maintaining multi-stable characteristics and significantly reducing energy barriers between potential wells. The study confirms that the quad-stable configuration is highly efficient for energy harvesting, and practical recommendations are provided for optimizing system parameters to maximize performance in practical applications.</p>