Hitachi Ltd and Hitachi Automotive Systems Ltd developed a high-efficiency, high-output inverter for hybrid vehicles (HEVs) and electric vehicles (EVs).
Compared with Hitachi’s existing product, the power loss of the inverter is 60% smaller, and its electric power capacity per volume is about 100% larger. The two companies expect that the new inverter will realize a long drive range and improve acceleration performance.
This time, Hitachi and Hitachi Automotive Systems developed a full-SiC power module and an inverter equipped with the module for HEVs and EVs by using SiC/GaN parallel packaging technology and double-side-cooling power module technology that they developed in the past.
For example, the parallel packaging technology was used to equalize the timing of switching on/off each SiC power semiconductor. In other words, a circuit board that equalizes the length of the control signal line connected to each SiC power semiconductor was developed to equalize the resistance characteristics of circuits. As a result, it became possible to fully exploit the low-resistance properties of SiC power semiconductor, increasing power capacity.
Also, for the new inverter, circuits are stacked so that the directions of load currents become opposite to one another, and it is stored in the can-like metal cooling fin of the double-side-cooling power module. As a result, the cooling fin offsets the magnetic field generated by the circuits so that the magnetic field energy stored in the circuits is reduced.
The newly-developed double-side-cooling full-SiC power module will be exhibited at the 44th Tokyo Motor Show 2015, which will be open to the public from Oct 30, 2015, in Tokyo.