Analysis of the three-chip switching cells approach for integrated multiphase power converter combining monolithic and hybrid techniques: Experimental validation on SiC and Si power assembly prototypes

In this paper, the authors present a novel integration approach for multi-phase IGBT module, based on both monolithic and hybrid integration methods. In this proposed “3-chip” approach, the discrete switches are integrated into three generic monolithic multi-pole power chips and assembled with a judicious packaging. This reduces significantly the commutation loop area and so the stray inductance responsible of overshoot voltage and common-mode dv/dt effect. The operating modes of the multi-pole chips were validated in an inverter application by 2D simulations under mixed-mode Sentaurus^TM. In order to characterize the commutation loop of the 3-chip approach, two prototype power modules with different technologies (Si and SiC dies) have been realized on PCB substrates. The stray inductances were measured using a precision impedance analyzer (frequency analysis). A double-pulse characterization was also performed to illustrate the effect of stray inductance reduction at the turn-off (temporal analysis). For comparison purposes, two “classical” power converters have been also realized and analyzed. According the results, measurements and analytic estimates, the proposed packaging design allows reducing the stray inductance by at least a ratio of two as compared to the classical layout.