Abstract: Under the changing output power and heat dissipation conditions of the optical storage unit interface converter in the optical storage microgrid, existing junction temperature algorithms of insulated gate bipolar transistor (IGBT) are difficult to evaluate its impact on the thermal diffusion angle of the IGBT module, resulting in limited junction temperature algorithm accuracy and posing a huge challenge to system thermal management. To address the above issues, this article proposes a junction temperature algorithm of IGBT in the interface converter in optical storage microgrid systems that considers three-dimensional transverse heat conduction (3-D THC). Firstly, in the optical storage microgrid system, considering the thermal coupling between multiple chips, a physical thermal model of power devices is established; Then, based on the established physical model, a junction temperature algorithm considering 3-D THC is further proposed, and a thermal network model considering 3-D THC is established, effectively improving the calculation accuracy of current state thermal parameters and power module thermal diffusion angle; Finally, the accuracy of the proposed model was verified using finite element analysis under the PinFin heat sink structure. The simulation results show that compared with various junction temperature algorithms, the proposed algorithm in this article has the smallest error in junction temperature calculation under steady-state and sudden power change conditions, with approximately 3.11% and 3.65% respectively, which is more accurate than not considering thermal diffusion angle (α=0) algorithm improved accuracy by 11.53% and 61.93% respectively; Under different heat dissipation conditions, the algorithm proposed in this article also has the highest junction temperature accuracy and the smallest error.

Key words: optical storage microgrid system, insulated gate bipolar transistor (IGBT) modules, three-dimensional transverse heat conduction (3-D THC), junction temperature calculation, finite element analysis