Information contained in this news release is current as of the date of the press announcement, but may be subject to change without prior notice.
March 15, 2012
- Size decreased to 2/3 of conventional modules using Si -
Tokyo, March 15, 2012 --- Hitachi, Ltd. (NYSE: HIT / TSE: 6501, "Hitachi") today announced the development of a compact 3.3kV/1200A (ampere) hybrid module for rail car inverters having a high voltage resistance of 3.3kV using SiC (silicon carbide), a material receiving much attention as the next generation power device material replacing Si (silicon). The hybrid module developed combines 3.3kV SiC-SBDs (Schottky barrier diode) and Si-IGBTs (Insulated gate bipolar transistors). To achieve a compact size module, Hitachi developed optimization technologies for the SiC-SBD structure and the Si-IGBT device characteristics taking full advantage of device, circuit and loss simulations, and succeeded in reducing the module size to approximately two-thirds that of current Si modules (Hitachi comparison). The 3.3kV compact hybrid module developed will contribute to the decrease in size, weight and power consumption of high voltage rail car inverters which draw from 1500V overhead wires.
In recent years, environmental measures are being undertaken on a global scale to achieve a low carbon society to preventing further global warming. There is a growing market for railways as a transport system with low environmental impact but there is also a need for compact environment-friendly rail car power modules which will contribute to decreasing the size and weight of inverters for rail cars.
Compared to the currently prominent Si, the breakdown field strength of SiC is nearly 10 times higher. The high voltage resistance allows resistance loss during conduction (ON), resulting from a thinning of the device, to be reduced thus gathering attention as a candidate material for smaller power modules or simpler cooling systems. Current domestic rail inverters are mainly designed for a high voltage of 1500V from overhead wires and therefore downsizing of high voltage power modules is important. In 2009, Hitachi developed 3kV-class SiC-SBDs which employ a JBS (Junction Barrier Schottky) structure that combines Schottky junctions with pn (positive-negative) junctions, and mounted these in a power module, which led to the development of this compact SiC hybrid module for railcar inverters. Features of the technology developed are as below :
Hitachi, Ltd., (NYSE: HIT / TSE: 6501), headquartered in Tokyo, Japan, is a leading global electronics company with approximately 360,000 employees worldwide. Fiscal 2010 (ended March 31, 2011) consolidated revenues totaled 9,315 billion yen ($112.2 billion). Hitachi will focus more than ever on the Social Innovation Business, which includes information and telecommunication systems, power systems, environmental, industrial and transportation systems, and social and urban systems, as well as the sophisticated materials and key devices that support them. For more information on Hitachi, please visit the company's website at http://www.hitachi.com.