Toyota to road test SiC Power Semiconductors
Using a "˜Camry' hybrid prototype and a fuel cell bus, Toyota Motor Corporation will be road testing the performance of SiC power semiconductors. The company hopes this will lead to significant efficiency improvements in hybrids and other vehicles with electric powertrains.
At present, power semiconductors account for approximately 20 percent of a vehicle's total electrical losses, meaning that raising the efficiency of the power semiconductors is a promising way to increase powertrain efficiency.
By comparison with existing silicon power semiconductors, the newly developed high quality SiC power semiconductors create less resistance when electricity flows through them. The technologies behind these SiC power semiconductors were developed jointly by Toyota, Denso Corporation, and Toyota Central R&D Labs.
In the Camry hybrid prototype, Toyota is installing SiC transistors and diodes in the power control unit's (PCU) internal voltage step-up converter and the inverter that controls the motor. Data gathered will include PCU voltage and current as well as driving speeds, driving patterns, and conditions such as outside temperature.
By comparing this information with data from silicon semiconductors currently in use, Toyota will assess the improvement to efficiency achieved by the new SiC power semiconductors. Road testing of the Camry prototype will begin (primarily in Toyota City) in early February 2015, and will continue for about one year.
Similarly, on January 9, 2015, Toyota began collecting operating data from a fuel cell bus currently in regular commercial operation in Toyota City. The bus features SiC diodes in the fuel cell voltage step-up converter, which is used to control the voltage of electricity from the fuel cell stack.
Data from testing will be reflected in development, with the goal of putting the new SiC power semiconductors into practical use as soon as possible.