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This paper presents an on-line monitoring method of IGBT module bond wires aging based on the phase-frequency characteristics (PFCs) of differential mode (DM) interference signal. Firstly, the collector current variation during IGBT chip switching is analyzed, and the relationship between the aging degree of bond wires and the PFCs of DM interference signal is studied; Secondly, a phase angle characteristic measurement system of DM interference signal is built and used to online monitor the aging of bond wires in IGBT module; Finally, taking the buck converter composed of IGBT module as the equipment under tested, the interference signal is extracted by the RF current probe and processed by the low-pass filter and signal amplifier, then the phase angle characteristics are measured by the oscilloscope board to realize the on-line monitoring of the bond wires aging of IGBT module. The experimental results show that compared with buck converter with healthy IGBT module, the phase angle of DM interference signal in Buck Converter with aging IGBT module is reduced. The proposed method does not need expensive equipment such as spectrum analyzer, and only needs to monitor the aging state of bond wires in IGBT module online through oscilloscope board. Besides, the research method in this paper provides an approximate linear monitoring method for bonding wire lift-off. [ABSTRACT FROM AUTHOR]

This article presents a method for monitoring the aging of insulate gate bipolar transistor (IGBT) module bond wires based on the spectrum characteristics of differential mode (DM) interference signals. The buck converter composed of IGBT modules is used as the device under test. The path of DM current in buck converter passes through the IGBT module, so the DM current is more suitable for monitoring the status of the module. The DM electromagnetic interference (EMI) in buck converter is mainly generated by the rapid decrease of the collector current, and the aging degree of bond wires is directly related to the DM EMI signal. The aging degree of bond wires inside IGBT module is monitored by the peak value of DM EMI signal in low frequency band. The experimental results show that the DM EMI amplitude of buck converter with aging IGBT module is larger than that of the buck converter with healthy IGBT module. The main advantage of the method proposed in this article is that it is independent of temperature and can realize the on-line accurate monitoring of the aging of the bond wires inside the IGBT module through the current probe under the actual working conditions. [ABSTRACT FROM AUTHOR]

The void in the solder layer is one of the most important aging forms of the insulated-gate bipolar transistor (IGBT) module. In this article, the influence mechanism of different void fractions on the thermal conductivity and specific heat capacity of the solder layer is studied. An improved Cauer model considering the void damage of the solder layer is established, and its model parameter extraction method is proposed. In addition, the temperature dependence of the Cauer model and its parameter is discussed in this article. In order to facilitate the experimental study of void damage in the solder layer, we customized IGBT modules with different void fractions. The influence of void morphology on the thermal properties of the solder layer is studied by the finite-element method, and the research purpose is to verify that void fraction can represent the effect of the voids on IGBT thermal characteristics. Considering the thermal resistance and thermal capacitance affected by the voids in the solder layer, their calculation methods are given in detail. Then, under different loads, the IGBT modules with different void fractions are tested. The robustness of the improved Cauer model is verified by the experimental and numerical simulation results. The results show that the improved Cauer model has higher accuracy than the traditional Cauer model. [ABSTRACT FROM AUTHOR]

An insulated-gate bipolar transistor (IGBT) module has two aging modes: 1) bond wire fatigue and 2) solder fatigue, both of which have a significant impact on the reliability of power electronic systems. A good way to increase the service life of such systems is to apply different compensation strategies according to different aging modes. As one of the simplest parameters in online measurements, the ON-state voltage is influenced by both types of fatigue, but its changes are not due solely to the aging of the IGBT module. Considering how the collector current and junction temperature influence the ON-state voltage, this article separates the ON-state voltage into three parts for the purpose of diagnosing IGBT module fatigue. In this article, the package voltage was extracted, which reflects the bond wire fatigue influence on the ON-state voltage of the IGBT module directly. This supplements the existing diagnostic method and realizes fatigue diagnosis under different working conditions. [ABSTRACT FROM AUTHOR]

A model for the online estimation of junction temperature based on the gate pre-threshold voltage in high-power insulated-gate bipolar transistors (IGBTs) was proposed. First, the turn-on behavior and temperature dependence of the gate-emitter voltage during the turn-on delay period were studied. It was revealed that the turn-on waveform of the gate-emitter voltage exhibits a point of inflection after which the voltage between the gate and emitter increases significantly; at this point, the relationship between the voltage and the temperature changes from a positive correlation to a negative correlation. Meanwhile, analyses on the basis of semiconductor physics revealed that the negative correlation between gate-emitter voltage and temperature is caused by the temperature dependence of the flatband voltage. Finally, a model for estimating the junction temperature was established based on a combination of the turn-on delay time and the gate prethreshold voltage which is negatively correlated with the temperature, to eliminate the effect of the bus voltage. [ABSTRACT FROM AUTHOR]

On-state voltage is an important thermal parameter for insulated gate bipolar transistor (IGBT) modules. It is employed widely to predict failure in IGBT module bond wires. However, due to restrictions in work environments and measurement methods, it is difficult to ensure the measurement accuracy for the on-state voltage under practical working conditions. To address this problem, an on-state voltage separation strategy is proposed for the IGBT modules with respect to the influence of collector current (Ic) and junction temperature (Tj). This method involves the separation of the on-state voltage into a dependent part and two independent parts during the IGBT module bond wire prediction. Based on the proposed separation strategy, the independent parts in the failure prediction can be removed, making it possible to directly monitor the voltage variations caused by bond wire failure. The experimental results demonstrate that the proposed diagnosis strategy can accurately predict the bond wire failure stage in an IGBT module under different conditions. [ABSTRACT FROM AUTHOR]

The on-state voltage is an important electrical parameter of insulated gate bipolar transistor (IGBT) modules. Due to limits in instrumentation and methods, it is difficult to ensure accurate measurements of the on-state voltage in practical working conditions. Based on the physical structure and conduction mechanism of the IGBT module, this paper models the on-state voltage and gives a detailed method for extracting the on-state voltage. Experiments not only demonstrate the feasibility of the on-state voltage separation method but also suggest a method for measuring and extracting the model parameters. Furthermore, on-state voltage measurements and simulation results certified the accuracy of this method. [ABSTRACT FROM AUTHOR]

Condition monitoring (CM) the insulated-gate bipolar transistor (IGBT) module is of vital significance to improve the reliability of power electronics system. Collector–emitter on-state voltage V C E , O N is a frequently employed failure precursor to identify the bond wire aging. In this paper, a method of separating V C E , O N is proposed to monitor the bond wire lift-off of IGBT module. Firstly, based on the circuit structure of IGBT module, the V C E , O N is divided into voltage drop across IGBT chip V C h i p and voltage drop across bond wire V B W . Secondly, the working principle of IGBT chip is investigated, and the calculation method of voltage drop across P-i-N diode V P i N is proposed. Finally, the V C h i p is analyzed, and information provided by collector current I C at the I C – V C h i p curve intersection point that is not affected by solder layer fatigue is adopted to monitor the lift-off degree of bond wire. The feasibility of the above methods is verified by theory and experiment. [ABSTRACT FROM AUTHOR]