| Power converter based on power electronic device is widely used, its reliability isbecoming increasingly outstanding.Insulated gate bipolar transistor combines theadvantages of GTR and MOSFET, easy to drive, strong current carrying capacity,and itis widely used in high-power converter.With the increasement of power level, especiallyin the harsh environment of such wind power, power volatility occasion, IGBTwithstand high imbalanced thermal stresses and its fatigue effect or failure will affectthe normal operation of power converter, so the reliability issues are to be solved.In order to improve the reliability of IGBT module, the current health status can beevaluated, to reduce the failure rate.To study the relations of IGBT electrical parametersand module aging degree is an important way to solve this problem.Further study of thespecific relationship various characteristics under different working point, differenttemperature and module aging degree can be used to to provide more information forthe aging state. How to accurately measure and record the electrical parameters of theIGBT with aging under different working conditions become the key point of the study.Currently there is no uniform standard related products at home and abroad,aiming atmore types of electrical parameters,a large amount of data, repeated changes workingconditions in the measurement process,the traditional manual test method has manyshortcomings which are poor measurement accuracy,low measurementspeed,multi-removal operation, high repeatability,limited scalability. Therefore, thispaper aims to study a set of IGBT electrical parameters accurately test system to providesupport for further research the relationship between IGBT electrical parameters andaging degree.At first, this paper qualitatively analyzes the relations of the module aging failureand all the electric parameters, through the further study of IGBT module failuremechanism. According to the close degree of all the electric parameters and agingstate,it selects the saturation voltage drop and threshold voltage, the turn-off time as themain characteristics. And based on the physical mechanism of the module, the physicalexpression of each electrical parameter is deduced the derived and external influencingfactors are analysied. With a capacity of1200V/75A insulated gate bipolar transistors asan example, combined with system-related requirements and basic test methods for eachelectrical parameter this article make a detailed test plan and test indicators of system. Next,the article discusses hardware and software problems of the test system.Itdesigns and analysises the test circuit, hardware selection to make the test system canachieve a high precision test of electric parameters.In addition combined with virtualinstrument graphical software-LabVIEW it has realized the automatic test function ofthe system. The system can not only measure regularly IGBT electrical parametersunder different current and different temperature,can also measure and savesimultaneously a variety of parameters,such as the saturation voltage, thresholdvoltage,turn-off time.Finally, this paper verified the accuracy and stability of the test results of the testsystem. All work by a single test point repeatability test in a short period of time and allworking point repeatability tests during different time periods after a long time showthat the test system for the electric parameter test has high accuracy and high stability.Compared with the traditional manual test method,It has a short development cycle, thehigh test precision and can save more than80%of the measuring time. In addition, thepaper collected and analyzed the electric parameter data in the process of the aging withthe help of a power cycle accelerated aging test. Research results lay a foundation forthe state assessment of the module. |
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