Abstract - This paper presents a two-phase cooling method
using RI34a refrigerant to dissipate the heat energy (loss)
generated by power electronics (PE) such as those associated with
rectifiers, converters, and inverters for a specific application in
hybrid-electric vehicles (HEVs). The cooling method involves
submerging PE devices in an R134a bath, which limits the
junction temperature of PE devices while conserving weight and
volume of the heat sink without sacrificing equipment reliability.
First, experimental tests that included an extended soak for
more than 300 days were performed on a submerged IGBT and
gate-controller card to study dielectric characteristics,
deterioration effects, and heat flux capability of R134a. Results
from these tests ilIustrate that R134a has high dielectric
characteristics, no deterioration on electrical components, and a
heat flux of 114 W/cm2 for the experimental configuration.
Second, experimental tests that incIuded simultaneous
operation with a mock automotive air-conditioner (A/C) system
were performed on the same IGBT and gate controller card. Data
extrapolation from these tests determined that a typical
automotive A/C system has more than sufficient cooling capacity
to cool a typical 30 kW traction inverter.
Last, a discussion and simulation of active cooling of the IGBT
junction layer with R134a refrigerant is given. This technique
will drastically increase the forward current ratings and
reliability of the PE device.