To address the issue of insufficient control accuracy in high-power electrodynamic speakers driven by high-frequency voltage, a fractional-order PID controller based on the D decomposition method was designed. An efficient controller parameter tuning strategy was proposed, and a new calculation method for the impact of model parameter errors on the controller's robustness was introduced. The designed controller was applied to a high-frequency signal-driven electrodynamic speaker model for testing. Experimental results show that compared with traditional controllers, the newly designed fractional-order PID controller reduced settling time by 6.07 ms, peak time by 1.03 ms, and steady-state relative error by 0.567 5%. Additionally, the robustness of the control system was significantly improved, with only one sensitive frequency point retained, and the minimal value of the robustness boundary was increased by 9.06‰. These improvements significantly enhanced the control performance of the electrodynamic speaker, providing a new solution for the control of high-power high-frequency drive systems.