Abstract: Aiming at the problems of low efficiency and large torque ripple faced by traditional induction motor drive systems during the switching between high/low speeds and light/heavy loads when the fans and pumps in HVAC systems operate under wide working conditions, this paper designs a pole-phase modulation induction motor (PPMIM) drive system based on frequency converters. It constructs a four-layer closed-loop architecture consisting of a working condition perception layer, a pole-phase decision and control layer, a multi-level frequency conversion drive layer, and a PPMIM execution layer. The inter-layer collaboration is optimized through Kalman filtering, fuzzy PID, and pre-modulation compensation algorithms, and a 6-unit cascaded H-bridge topology and a carrier phase-shift modulation strategy are adopted to adapt to the pole-phase switching requirements. Simulation verification shows that this scheme can significantly improve the operating efficiency and stability of HVAC under wide working conditions.