Toyota looking to increase hybrid efficiency with new semiconductors
Toyota is looking to better their hybrid’s fuel economy by about ten percent with their next generation of hybrid power units.
Toyota, working along side supplier Denso, is working on developing a new power control unit to replace the current silicon semiconductors with silicon carbide – SiC – versions.
According to the Japanese car maker, the current power control units are responsible for up to a quarter of the electrical power loss in current hybrid cars, with the silicon semiconductors accounting for about eighty percent of that wastage.
The current power control unit – PCU – from Toyota’s Hybrid Synergy Drive system, is responsible with the channelling power to the electric motor to regulate road speed or petrol motor assistance, alongside the funnelling of energy recovered from the regenerative braking from the electric motor to the battery pack. This means that the semiconductors that the PCU is made of do all the grunt work, switching power flow on and off.
When silicon semiconductors switch off, a tail current continues to flow for a short period of time afterwards. The SiC versions don’t have the same problem, which allows them to work at higher frequencies as well as suffering less power loss than their silicon-only counterparts. These efficiencies will also allow for the PCU size to be reduced by eighty percent.
The ultimate aim of the project is to improve the efficiency for electrified cars by about ten percent under Japan’s JC08 fuel economy testing cycle. This regime is known to produce numbers that are larger than those used by the US and the EU.
According to Toyota, they plan to start testing the new power control unit on public roads in Japan during 2015. It is not yet known if this new SiC power control unit will be ready in time for the next generation Prius or Toyota’s hydrogen fuel cell vehicle due next year.
