ANALYSIS OF HEAT LOSS AND OPEN CIRCUIT FAULT ON T-NPC INVERTER IN WIND ENERGY CONVERSION SYSTEM
DOI:
https://doi.org/10.62985/j.huit_ojs.vol26.no2E.377Keywords:
Inverter voltage source, T bridge inverter, Open circuit error, Total harmonic distortion, PWM techniqueAbstract
This research provides an in-depth analysis of thermal losses and open-circuit fault tolerance of the three-level T-Type Neutral Point Clamped (T-NPC) inverter, applied in the power conversion system of a wind energy conversion system. The core objective is to evaluate the thermal performance and reliability of the T-NPC topology compared to the conventional Neutral Point Clamped (NPC) structure, which is particularly crucial in high-reliability wind power systems. The paper conducts a comparative study on both the three-level NPC and T-NPC inverter topologies under the same Carrier-Based Pulse Width Modulation (CPWM) strategy. The research delves into the analysis of conduction losses and switching losses for individual IGBT and diodes. The thermal analysis results reveal a significant difference in total thermal losses across the components. Due to the specific topology and the duty cycle distribution inherent in CPWM, the T-NPC configuration exhibits a notable uneven thermal distribution across its legs, yet achieves a reduction in total switching losses compared to the NPC under identical operating conditions. The central focus of this study is the investigation of the effects of the open-circuit fault occurring at the T-branch of the T-NPC inverter. Based on the fault impact analysis on the output voltage quality and wind energy conversion system current, the paper proposes a suitable control method based on Carrier-Based PWM. This method enables the system to continue operating with acceptable harmonic quality (Fault-Tolerant Control) upon the detection of an open-circuit fault in the T-branch. These findings and proposals provide crucial data for the selection and design of highly efficient and reliable three-level inverters for renewable energy applications.
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