Hidekazu Tanisawa

40 kW/L High Switching Frequency Three-Phase AC 400 V All-SiC Inverter

We, the R&D Partnership for Future Power Electronics Technology (FUPET), have reported a forced-air-cooled DC 600 V three-phase AC 400 V inverter built with SiC-JFETs and SiC-SBDs and designed to attain an output power density (OPD) of 40 kW/L with a switching frequency (fSW) of 50 kHz. This paper reports the test results of this inverter attaining an OPD of 40 kW/L in operating a 3-phase motor with fSW = 50 kHz, and an OPD of more than 60 kW/L in operating an equivalent circuit with fSW = 20 kHz by adopting specialized high speed drive circuit boards.

Power Module Package Structure Capable of Surviving Greater ΔTj Thermal Cycles

A new SiC power module package structure is proposed that is capable of withstanding greater ΔTj cycle stress. Its most notable feature is the use of a SiN substrate having Cu/Invar/Cu foils (C/I/C thickness ratio of 1/8/1) brazed on both sides as conductor plates. The CIC foils show a very low coefficient of thermal expansion (CTE) of 5.1 ppm/°C and therefore can significantly reduce package degradation resulting from the larger CTE mismatch of the conductor to SiC and SiN. A thermal cycle test (TCT) was conducted between -40°C and 250°C (ΔTj = 290°C). It was found that the SiC/Au-Ge/CIC-SiN die attachment maintained joint strength of 78 MPa even after 3000 cycles.

Development of a Wire-Bonding-Less SiC Power Module Operating over a Wide Temperature Range

In this paper, we describe a power module fabricated using SiC metal–oxide–semiconductor field-effect transistors (MOSFETs). A C-R snubber is integrated into this power module for reduction of the surge voltage and dumping of the voltage ringing. The four SiC MOSFETs are sandwiched between active metal copper (AMC) substrates. The surfaces of the SiC MOSFETs are attached to AMC substrates by Al bumps, owing to which the power module shows low inductance. Moreover, this power module ensures credibility and reliability at higher operating temperatures beyond 200 °C. The switching characteristics of the module are studied experimentally for high-temperature and high-frequency operations.

Switching analysis for all-SiC module

In this paper, we propose a method to accurately calculate the turn-off switching loss. For that purpose, a simple analytical model is proposed in which the parasitic capacitances and stray inductances are integrated within the power module. Experiment confirmed that the turn-off loss analyzed by this model is correct.