To meet the high-precision control requirements of Permanent Magnet Synchronous Motors (PMSM) in servo systems, this study investigates a sensorless hybrid control strategy, overcoming the issues of low reliability and high cost associated with traditional mechanical sensors in harsh environments. The proposed method combines the characteristics of low-speed and high-speed operation by integrating a high-frequency (HF) signal injection algorithm with a flux observer algorithm into a hybrid observation strategy: at low speeds, rotor position information is extracted using HF injection, while at high speeds, the flux observer algorithm is employed. To address the switching between these two algorithms, a weighted switching algorithm with a phase compensation mechanism is designed to enhance estimation accuracy and reduce torque transients. Simulation and experimental results demonstrate that the hybrid strategy achieves accurate rotor position and speed estimation across the entire speed range, effectively suppresses torque ripple, and ensures stable motor operation. This research provides a feasible sensorless technical solution for PMSM control, offering significant theoretical and engineering value for improving the reliability and environmental adaptability of servo systems.