Advanced Power Cycling Tests of SiC MOSFET Power Modules
Author
Santibañez Ponce, Jose Benjamin
Term
4. term
Education
Publication year
2025
Submitted on
2025-05-28
Pages
45
Abstract
Wide bandgap-enheder som SiC og GaN lover højere effektivitet og bedre varmetransport, men deres udbredelse begrænses af pågående pålidelighedsbekymringer. Dette speciale undersøger, hvordan man kan udføre power-cycling-tests på SiC MOSFET-effektmoduler ved at tilpasse en eksisterende platform, der kan køre både DC- og AC-power-cycling. En adapter-Print (PCB) blev udviklet for at integrere halvbro-SiC-moduler i et tidligere IGBT-baseret testsæt, hvorefter både DC- og AC-tests blev gennemført. Under arbejdet blev der identificeret problemer med måling af on-state-spænding, som kan spores til stærkere EMI forårsaget af SiC-modulernes hurtige switchning og interferens i ADC-kommunikationen; mulige afhjælpninger blev undersøgt. Resultaterne viser tydelige forskelle i junction-temperaturprofiler mellem DC- og AC-cycling: bølgeform og termisk impedans påvirker forløbet, og DC giver en mere aggressiv temperaturstigning, som kan afvige fra feltforhold i fx motorstyringer med sinusformet strøm. Desuden indikerer DC-power-cycling pakningsdegradering i form af bond wire lift-off, som ses som hurtige stigninger og spring i on-state-spændingen. Arbejdet bidrager med praktiske erfaringer til både tilpasning af testudstyr og tolkning af målinger ved vurdering af SiC-modulers pålidelighed.
Wide bandgap devices such as SiC and GaN offer higher efficiency and improved thermal performance, yet their broad adoption is limited by reliability concerns. This thesis examines how to perform power cycling tests on SiC MOSFET power modules by adapting an existing platform capable of DC and AC power cycling. An adapter PCB was designed to integrate half-bridge SiC modules into a previously IGBT-based test setup, and both DC and AC tests were executed. During testing, issues in on-state voltage measurement were identified and traced to stronger EMI from the faster switching of SiC devices, interfering with ADC communication; potential mitigations were explored. The results show clear differences in junction temperature profiles between DC and AC cycling: the current waveform and thermal impedance shape the response, with DC producing a more aggressive temperature rise that may deviate from field operation in applications like motor drives with sinusoidal currents. Moreover, DC power cycling revealed packaging degradation—specifically bond wire lift-off—observable as rapid increases and jumps in on-state voltage. The work provides practical guidance for adapting test setups and interpreting measurements when assessing SiC module reliability.
[This abstract was generated with the help of AI]
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