Search

Multichip insulated gate bipolar transistor (mIGBT) power modules (PMs) degrade over power cycling. Bond wire lift–off is one of the major failure modes. This article presents a technique to diagnose bond wire lift-off by analyzing the on -state voltages across collector and emitter terminals and the voltages across collector and Kelvin emitter terminals. The proposed method can indicate the first lift-off out of 37 bond wires in a mIGBT. The main novelty of the proposed technique is that it can locate the chip that has bond wire lift-off(s). In addition, the temperature dependence of the proposed approach is negligible. The article describes the proposed technique in detail and shows results and discussions based on practical tests which are carried out on two mIGBT PMs with different packages.

This paper proposes a novel health-sensitive parameter, called the gate–emitter pre-threshold voltage V GE(pre-th), for detecting IGBT chip failures in multichip IGBT power modules. The proposed method has been applied in an IGBT gate driver and measures the V GE at a fixed time instant of the V GE transient before the threshold voltage occurs. To validate the proposed method, theoretical analysis and practical results for a 16-chip IGBT power module are presented in the paper. The results show a 500 mV average shift in the measured V GE(pre-th) for each IGBT chip failure.

Temperature sensitive electrical parameters (TSEPs) are promising for measurement of the insulated gate bipolar transistor (IGBT) junction temperature. Many TSEPs have been proposed in the literature and most require current sensors, and convoluted hardware and data processing, which are associated with increased complexity and cost. In this letter, a new TSEP is proposed called prethreshold TSEP, $V_{{\rm GE}({\rm pre}\text{-}{\rm th})}$ . $V_{{\rm GE}({\rm pre}\text{-}{\rm th})}$ requires only a voltage sensor and a counter. Besides less hardware requirement, $V_{{\rm GE}({\rm pre}\text{-}{\rm th})}$ does not suffer from self-heating—a problem that most TSEPs encounter. This letter presents the operation of $V_{{\rm GE}({\rm pre}\text{-}{\rm th})}$ with the help of simulation. Experimental tests on a 3.3 kV, 800 A IGBT were conducted to characterize $V_{{\rm GE}({\rm pre}\text{-}{\rm th})}$ . It is shown that the new TSEP proposed has a sensitivity of −2.2 mV/°C .