| With the deployment of energy security strategies,a large number of power electronic equipment has been put into production.Unplanned downtime and people’s expectations for the long-term safe operation of equipment make reliability a concern.As the core components of power electronic equipment,power semiconductor devices are prone to fatigue,which restricts the reliability of the equipment.Improving the reliability of power semiconductor devices plays an important role in enhancing the reliability of power electronic equipment.Health status monitoring is an effective means to actively improve the reliability of power semiconductor devices,and it is also an important branch of reliability research.Since insulated gate bipolar transistor(IGBT)is a widely used voltage-controlled power semiconductor device at present,the paper takes the commonly used bond-wired IGBT module as the research object,and studies the condition monitoring of junction temperature and bond wire defects frequently observed in the package-level failure.As the industry’s attention to reliability increases with power levels,the paper also studies the state monitoring of chip branch defects in multichip IGBT modules.The main work of the paper is as follows:1)Junction temperature is an important parameter of module reliability,which can be characterized by temperature-sensitive electrical parameters.The paper studies the turn-on process of the IGBT module driven by constant current source,and points out that the induced voltage on the parasitic inductance between the auxiliary emitter and the power emitter of the module can be used as the trigger signal to obtain the gate voltage with temperature information.Since the gate voltage is related to the threshold voltage,it is called the quasi-threshold voltage in the paper.The relationship between quasi-threshold voltage and junction temperature is verified,the influence of bond wire defects,load current and bus voltage on the threshold voltage is investigated.2)Bond wires fatigue is a common phenomenon in package-level failure of the IGBT module,which influences the electrical function of the module.For single-chip IGBT modules,the module transconductance includes not only the characteristics of the IGBT chip,but also the health status of the bond wires.The paper proposes a monitoring method for bond wire defects in single-chip IGBT based on module transconductance.First,the relationship between module transconductance and bond wires defects is established.Then,the safety measurement area and the temperature difference caused by the bond wires defects are discussed for safe and accurate measurement.A pulse ramp drive circuit is proposed to extract the module transconductance.Finally,the correctness of the theoretical analysis is verified through simulation and experiment.3)The failure of the bond wires would cause chip branch defects in the multichip IGBT module,which affects the gate input capacitance of the module.When the module gate injects a constant current,the time duration of gate charge when the gate voltage reaches the preset value will be shortened as the chip branch defects develop.The paper presents a method for monitoring chip branch defects in multichip IGBT module based on the time duration of gate charge.First,the relationship between the time duration and the chip branch defects is established.A monitoring circuit integrated with a driver is proposed,and the state monitoring principle of the circuit is discussed.Then,the experiment is carried out to verifies the feasibility of the monitoring method,and the influence of temperature and collector-emitter voltage on the condition monitoring is investigated.Finally,the characteristics of the monitoring method is discussed.4)In order to meet the demand of non-intrusive monitoring,the paper proposes a method based on gate charge to monitor the chip branch defect in multichip IGBT module.By accumulating the turn-on gate current for multiple switching cycles,the gate charge deviation due to the chip branch defects is converted into the voltage signal that is easy to collect.First,the relationship between gate charge and chip branch defect is established.Then,the principle of condition monitoring and a monitoring circuit which can be easily integrated into commercial drivers are proposed.Finally,The confirmatory experiment is carried out to verify the feasibility of the proposed method.Besides,the effects of temperature,load current and collector-emitter voltage on the monitoring results have been studied.The results show that the proposed method is non-intrusive and has the potential for real-time and online monitoring. |
