Abstract: A comprehensive study was conducted using numerical simulation techniques on a specific model of air conditioner outdoor unit, addressing the issue of smart power module (IPM) pin cracking observed during random vibration testing, and corresponding optimization solutions were proposed.Employing Finite Element Method (FEM), a refined simulation model encompassing key components such as the electronic control box, PCB, IPM module, and heat sink was established. The failure phenomenon was accurately reproduced, and its underlying mechanism was elucidated through modal analysis, random vibration response analysis, and harmonic response analysis. Based on root cause analysis, a structural optimization scheme was proposed. Simulation validation demonstrated that the stress level at the pin crack location of the IPM module was significantly reduced. Ultimately, the optimized design passed the physical prototype’s random vibration test in a single attempt, effectively eliminating the potential product quality risk.

Key words: Air conditioning, Random vibration, IPM module, Pin cracking, Finite element simulation, Modal analysis, Harmonic response analysis