This paper presents a method for the lifetime extension of a two-level inverter with a reduction in the DC-link ripple current and power module temperature. The reliability of inverters has been widely explored at the device and inverter levels based on the physics of failure analysis. Switching module and capacitor failures account for more than 50% of inverter system failures. The failures of these components are due to the accumulated thermomechanical damage caused by power loss and thermal stress. This study analyzes power loss and thermal stress by modeling the switching modules. The proposed method suppresses the thermal stress of switch modules by applying discontinuous PWM (DPWM) to reduce power loss. In addition, a phase-shifting scheme is applied to reduce the ripple current, which affects the loss and temperature of the DC-link capacitor. The feasibility of the proposed thermal reduction method is verified through simulation and experimental results.
This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korean government (MSIT), the Korea Institute of Energy Technology Evaluation and Planning (KETEP), and the Ministry of Trade, Industry & Energy (MOTIE) of the Republic of Korea (No. RS-2024-00333208, No. 20225500000110).
