Modular level converter power module reliability evaluation method

Abstract

A method for evaluating the reliability of a power module of a modular level converter, the method includes calculating junction temperature IGBT of IGBT and diode, junction temperature of diode and hot spot temperature of capacitor according to model data of IGBT module, model data of capacitor and MMC task profile, calculating junction temperature IGBT of IGBT and diode in steady state, calculating junction temperature of diode and hot spot temperature of capacitor, calculating junction temperature IGBT of capacitor, calculating junction temperature IGBT of IGBT and hot spot temperature IGBT, calculating junction temperature IGBT. The junction temperature of IGBT and diode is counted by rainflow counting method, and the low frequency thermal cycle list of the whole year is obtained. TheIGBT, diode and capacitor lifetime values are calculated by the preset lifetime model according to the low frequency thermal cycle list and the hot spot temperature of the capacitor. The Weibull lifedistribution is used to evaluate the reliability of the power module in the MMC. The electric thermal stress energy in the MMC is fully taken into account in the method. The method has good engineering applicability for evaluating the reliability of the MMC under different task profiles. At the same time, it overcomes the shortcomings of insufficient samples of life statistics data of DC engineering components.

Description

technical field [0001] The invention relates to the technical field of evaluation of power modules of modular level converters, in particular to a method for evaluating the reliability of power modules of modular level converters. Background technique [0002] For a long time, the reliability of the converter, the core component of the flexible DC transmission system, has been poor, especially under high-frequency switching. main obstacle. In recent years, the modular multilevel converter (MMC) has greatly promoted the development of flexible DC transmission technology with its high-quality output waveform and low power loss. The heating of flexible DC transmission directly affects its reliability, reduces its lifespan and increases the cost of the whole life cycle of the system. Therefore, analyzing the loss mechanism of MMC and evaluating the life of MMC will not only help to find out the weak links of MMC, lay a theoretical foundation for continuous improvement of produ...

AI Technical Summary

Problems solved by technology

The MMC used for flexible DC transmission has a high voltage level, a large number of power modules, compact module layout, and difficult heat dissipation

Due to the different installation location environment and working conditions of MMC, the reliability of the converter is different; in addition, the flexible DC project has only been developed in recent years, and the number is limited, the data sample of component failure is small, and the data is limited; while the traditional The MMC reliability research is based on the known component failure failure rate, or based on the statistical failure rate, but does not involve the electrothermal stress of IGBT, diode and capacitor, and cannot identify the reliability of MMC in different applications.

Images