Developing new lifetime prolongation SVM algorithm for multilevel inverters with thermally aged power devices

Abstract

Research concerns have grown towards precede diagnosis and prognosis of faults in power converters that result from thermal overheating problems of semiconductor devices. These problems directly affect the overall system availability and reliability as well. Many papers in the literature have addressed these problems. However, almost all of them suffer from major challenges such as increased components count, reduced output current ratings, reduced output voltage levels, and unbalanced voltages over the DC-link capacitors. These challenges impede the maximum energy harvesting, especially in renewable energy systems. A novel space vector modulation (SVM) algorithm has been proposed for lifetime prolongation of thermally aged power semiconductor devices in multilevel inverters. The proposed SVM algorithm functions to alleviate the affected device and to prevent the harmful consequences such as short-open circuit faults. The feasibility of the proposed method has been verified by simulation and experimental results on the three-phase three-level T-type inverter and compared with the previously addressed approaches. It can be concluded that the proposed algorithm provides a significant reduction of thermal stresses on the thermally aged power devices in addition to maintaining the same components count, the same output ratings, the same output levels, and balanced capacitors’ voltages as well.