A Modified Carrier Switching Scheme to Balance the Capacitor Voltage and Power Loss of GaN Based Neutral Point Clamped Inverters

Pulse width modulation (PWM) methods are pivotal in optimizing the performance and efficiency of multilevel inverters (MLIs). This paper introduces a novel modified carrier-based switching scheme tailored to address critical challenges such as DC-link capacitor voltage fluctuations, power losses, and thermal stress in the three-phase 3-level neutral-point-clamped (NPC) inverters. The proposed method achieves better performance, reducing the DC-link voltage imbalance to an unprecedented 4.17 V while also minimizing peak temperature, significantly outperforming traditional triangular, phase opposite deposition (POD) PWM, and interleaved carrier (IC) based PWM. Additionally, the method achieves remarkable power loss reductions. The integration of GaN HEMT devices, leveraging their wide bandgap advantages, further reduces total losses and enhances overall system efficiency. By offering superior thermal management and enhanced system reliability, this approach sets a new benchmark for MLIs, promising transformative advancements in power electronics and renewable energy systems. The entire system is modeled and simulated using the software platforms PLECS and MATLAB/Simulink. A reduced-scale laboratory prototype is built and tested to validate the performance of the proposed modulation technique.