DENSO develops its first inverter using SiC power semiconductors
Highly efficient silicon carbide chips significantly reduce power loss in electric vehicles
DENSO CORPORATION, a leading OE mobility supplier and parent company of DENSO Aftermarket, has announced the development of its first inverter with silicon carbide (SiC) semiconductors. This inverter, which is incorporated into the eAxle, an electric driving module developed by BluE Nexus Corporation, will be used in the new Lexus RZ, the vehicle manufacturer’s first dedicated battery electric vehicle (BEV) model, which was released at the end of March 2023.
SiC power semiconductors, which consist of silicon and carbon, significantly reduce power loss compared to silicon (Si) power semiconductors. In a cruising test, conducted under specific conditions by a BEV using a SiC semiconductor inverter, a reduction in power loss of more than 50% was demonstrated when compared with a BEV using an inverter with a traditional Si semiconductor. Therefore, as a result of using a SiC semiconductor inverter, the BEV’s energy efficiency is improved and its cruising range is extended.
Key elements of the new inverter development
SiC power semiconductors with DENSO’s unique trench-type metal-oxide-semiconductor (MOS) structure*1 improve the output per chip because they reduce power loss caused by generated heat, which allows the unique structure to achieve a high voltage and low On-resistance*2 operation.
Key elements of the new inverter manufacture
Based on the high quality technology jointly developed by DENSO and Toyota Central R&D Labs., Inc., DENSO utilises SiC epitaxial wafers*3 that incorporate the results of work commissioned by New Energy and Industrial Technology Development Organization (NEDO). As a result, DENSO has halved the number of crystal defects that prevent the device from operating normally due to the disorder of the atomic arrangement of the crystal. By reducing crystal defects, the quality and stable production of SiC power semiconductor devices used in vehicles, are ensured.
DENSO Power Card
DENSO calls its SiC technology “REVOSIC®,” and uses it to comprehensively develop technologies for products ranging from wafers to semiconductor devices and modules such as power cards. DENSO will contribute to the realisation of a carbon neutral society through development aimed at more efficient energy management for vehicles, while also utilising the grant from the Green Innovation Fund (GI Fund) *4, which was adopted in 2022.
*1 DENSO’s unique trench-type MOS structure: Semiconductor devices with a trench gate using DENSO’s patented electric field relaxation technology.
*2 On-resistance: A measure of the ease of current flow: the lower the value, the lower the power loss.
*3 SiC epitaxial wafers: SiC single crystalline wafers with SiC epitaxially grown thin layer.
*4 Green Innovation Fund (GI Fund): GI Fund was created by the Ministry of Economy, Trade and Industry (METI) and assigned to NEDO with the aim of achieving carbon neutrality by 2050. DENSO has been selected to receive subsidies for a project to develop manufacturing technology for next generation power semiconductor devices for electric vehicles.
Further details of the DENSO Aftermarket programme are available online at: www.denso-am.eu