Study On Condition Monitoring Method Of IGBT Module In Wave Power Converter

With the continuous consumption of non-renewable energy,the development and utilization of various renewable energy sources has become an important development strategy for all countries in the world.my country's vast sea area is very conducive to the development and utilization of ocean energy.As a kind of ocean energy,wave energy has the highest amount of actual development,which also makes it have the greatest development potential.The development and utilization of wave energy not only meets the energy development strategy,but also meets the needs of national defense.Due to the particularity of the marine environment,this also puts forward higher requirements for the reliability of the wave energy power generation system.The power converter is the core component of the new energy power generation system,and its long-term safe and reliable operation is essential to the entire power generation system.As a component of the power converter,the IGBT module is not only a key core part,but also a weak link in the converter,so it is particularly important to improve the reliability of the IGBT module.Condition monitoring is one of the important implementation methods to improve the reliability of power equipment.It monitors the health of power equipment in real time through characteristic quantities and provides maintenance instructions in time to prevent unexpected equipment shutdowns.Therefore,this article focuses on the wave energy power converter,taking its key component IGBT module as an example,and conducts a study on the condition monitoring of the decoupling of multiple characteristic quantities.In view of the high humidity and salt spray application scenarios of wave power generation,the fatigue aging failure mechanism of the IGBT module is summarized and analyzed,and the electrothermal characteristic parameters are determined according to different failure modes,and the coupling relationship between the parameters is analyzed.Then,on the basis of theoretical analysis,a state monitoring method was formulated to realize the decoupling between the various parameters and the failure modes.Finally,according to the determined electric heating parameters,a reasonable and safe condition monitoring circuit is used to complete the monitoring of the selected electric heating parameters and carry out experimental verification.The main work content of the thesis is as follows:(1)According to the operating conditions and environment of the IGBT module of the wave energy converter,the failure mechanism and the corresponding failure mode of the IGBT module of the wave energy converter under this background are determined.The main failure modes include:bond wire fatigue,solder layer fatigue,chip performance degradation,and module external port corrosion degradation.In order to monitor each failure mode,the saturation voltage drop V_ceon,leakage current I_ces,and temperature distribution?T are used to monitor bond wire fatigue and external port corrosion,chip performance degradation,and solder layer fatigue,respectively.Because there will inevitably be a coupling relationship between feature quantities.Therefore,this article analyzes the coupling relationship of the selected feature quantities one by one,which provides a theoretical basis for the subsequent research on condition monitoring methods.(2)Aiming at various failure modes of wave energy converters,a state monitoring method with decoupling of multi-characteristics is proposed.First of all,use temperature-independent points to eliminate the influence of solder layer fatigue on the saturation voltage drop V_ceon,and then only reflect the bond wire fatigue and external port corrosion degradation.At the same time,according to the different characteristics of bond wire fatigue and external port corrosion degradation,That is,the fatigue failure of the bonding wire causes the saturation voltage drop V_ceon(int)at the temperature irrelevant point to show a step change,and the corrosion deterioration of the external port causes it to change slowly and continuously,which can achieve the saturation voltage drop V_ceon on the bonding wire fatigue and external Decoupling state monitoring of port corrosion;Then,by calibrating the module leakage current curve of the same gate voltage and forward bias at different temperatures,the decoupling between the leakage current Ices and the temperature can be realized from the table look-up or numerical fitting method,so as to accurately monitor the chip performance.The purpose of the degradation state;Finally,since the temperature distribution?T is a relatively independent characteristic quantity and is only affected by the fatigue of the solder layer,the thermal simulation model of the IGBT module is established to analyze the change of the temperature distribution?T under different fatigue aging degrees of the solder layer.The law verifies the correctness of the method.Finally,since the temperature distribution?T is a relatively independent characteristic quantity and is only affected by the fatigue of the solder layer,the thermal simulation model of the IGBT module is established and the change law of the temperature distribution?T under different fatigue aging degrees of the solder layer is analyzed to verify this the correctness of the method.(3)Aiming at the proposed multi-feature decoupling state monitoring method,comprehensively considering the safety and accuracy of monitoring,the collection and monitoring of the selected feature quantities are realized,and the experimental verification is completed.This paper mainly realizes the monitoring of saturation voltage V_ceon,leakage current I_ces,temperature distribution?T,and on the three-phase converter platform,through the bonding wire fatigue,external port corrosion degradation,solder layer fatigue and chip performance degradation simulation experiments to verify the effectiveness of the proposed multi-feature decoupling state monitoring method.The above research results can be applied to the condition monitoring of the IGBT module of the wave power converter,which is beneficial to improve the reliability of the wave power converter,reduce the operation and maintenance cost,and has important engineering application value.