Abstract: To solve problems such as low automation and slow dynamic response in the tensioning systems of mining belt conveyors, this study proposed an innovative automatic tensioning control device incorporating a permanent magnet variable-frequency motor with constant-torque capability and developed a corresponding vector control strategy. A tension control transfer function model was established based on the dynamic characteristics of the belt conveyor’s tensioning mechanism, and the control system was simulated using Simulink. The results show that, with the motor output torque set to 650 N·m and the steady-state speed to 75 r/min, the motor speed and electromagnetic torque respond rapidly after startup and reach steady state within 0.058 s, while the three-phase stator currents stabilize into sinusoidal waveforms within 0.05 s. When a load torque disturbance is applied at 0.22 s, the motor torque, speed, and three-phase currents all quickly return to a steady state. Furthermore, the tension adjustment time achieved by the proposed control strategy is only 0.10 s. This approach significantly improves the degree of automation and dynamic response of mining belt conveyors, demonstrating the potential and advantages of permanent magnet variable-frequency technology for industrial automation.