Robust Sensor—Less PR Controller Design for 15-PUC Multilevel Inverter Topology with Low Voltage Stress for Renewable Energy Applications

Conventional multilevel inverters often suffer from high harmonic distortion and increased design complexity due to the need for numerous power semiconductor components, particularly at elevated voltage levels. Addressing these shortcomings, this work presents a robust 15-level Packed U Cell (PUC) inverter topology designed for renewable energy and grid-connected applications. The proposed system integrates a sensor less proportional-resonant (PR) controller with an advanced carrier-based pulse width modulation scheme. This approach efficiently balances capacitor voltage, minimizes steady-state error, and strongly suppresses both zero and third-order harmonics resulting in reduced total harmonic distortion and enhanced voltage regulation. Additionally, a novel switching algorithm simplifies the design and implementation, further lowering voltage stress across switches. Extensive simulation results validate the performance under various resistive and resistive-inductive load conditions, demonstrating compliance with IEEE-519 THD standards and robust operation under dynamic changes. The proposed sensorless PR-controlled 15-PUC inverter thus offers a compelling, cost-effective solution for efficient power conversion in next-generation renewable energy systems.