The transition toward electric mobility demands traction inverters that deliver high efficiency, thermal stability, and robust performance under diverse real-world driving conditions. This study introduces an AI-optimized three-level T-type Silicon Carbide (SiC) traction inverter designed for intelligent, energy-efficient electric vehicle (EV) propulsion. A Proximal Policy Optimization (PPO)-based controller is developed to dynamically regulate modulation index, switching frequency, and switching sequence, enabling coordinated loss-thermal optimization. The controller is trained on WLTP and UDDS drive cycles using a physics-based inverter, motor, and thermal model derived from SiC MOSFET datasheets. High-fidelity figures were produced using scientific plotting rather than simulation screenshots to ensure journal-standard reproducibility. The proposed inverter achieves significant improvements: switching losses are reduced by up to 52%, peak junction temperature is lowered by approximately 23%, and average drive-cycle efficiency is increased from 92.1% to 96.8%. These gains translate to an increase of 20-24 km in WLTP driving range for a 75-kWh battery EV. The results demonstrate that AI-assisted modulation can substantially enhance converter performance, reduce thermal stress, and support sustainable green-energy transportation systems.