The worldwide expansion of DC fast-charging infrastructure is accelerating to meet the continuously rising demand from the electric vehicle sector. This rapid growth imposes considerable pressure on existing electrical distribution networks, especially due to the increasing deployment of high-power charging stations and their strict requirements for maintaining power quality and grid stability. In this context, power electronic converters play a central role in enabling efficient and reliable energy conversion between the grid and electric vehicles. To address these issues, this paper proposes a nonlinear PI (N-PI) based control strategy for a Vienna rectifier–based EV charging system. The proposed control method is designed to enhance dynamic response, improve disturbance rejection capability, and maintain stable DC-link voltage regulation under varying operating scenarios, including reference changes, load variations, and imbalance conditions. Furthermore, an N-PI–based neutral-point balancing controller is applied in the Vienna rectifier system to reduce DC-link capacitor voltage imbalance and maintain stable midpoint voltage regulation. The effectiveness of the proposed approach is verified through comparative analysis with conventional PI control, demonstrating improved overall system performance and robustness for next-generation fast-charging applications.