Toyota To Test SiC Semiconductors In Camry Hybrid, Fuel Cell Bus

FEB 10 2015 BY MARK KANE 8

SiC-equipped Toyota Camry prototype

SiC-equipped Toyota Camry prototype

Toyota launched in Japan a test program to evaluate the performance of silicon carbide (SiC) power semiconductors (transistors and diodes) in power control units (PCUs) of a hybrid car and, in the case of FCVs, in the fuel cell voltage step-up converter.

According to the Japanese manufacturer, power semiconductors account for approximately 20 percent of total electrical losses. If the new SiC power semiconductors cut that loss significantly, efficiency (and range) of the cars will go up maybe even a few percent.

Another benefit would be downsizing of the components.

This month, Toyota will begin testing SiCs in a Camry Hybrid, while its hydrogen fuel cell bus already began tests in January. Real-world tests in Toyota City will last one year.


Power semiconductors are found in power control units (PCUs), which are used to control motor drive power in hybrids and other vehicles with electric powertrains. PCUs play a crucial role in the use of electricity, supplying battery power to the motors during operation and recharging the battery using energy recovered during deceleration.

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 silicon carbide (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., Inc. as part of the results of a broader R&D project* in Japan.

Toyota FC Bus

Toyota FC Bus

Test vehicles and period

In the Camry hybrid prototype, Toyota is installing SiC power semiconductors (transistors and diodes) in the PCU’s 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.

*Conducted by the R&D Partnership for Future Power Electronics Technology under consignment from the New Energy and Industrial Technology Development Organization.”

Power control unit

Power control unit

Power control unit

Power control unit

“Using a “Camry” hybrid prototype, Toyota will bring a brand new technology to the streets of Japan for testing this year. The tests will evaluate the performance of silicon carbide (SiC) power semiconductors, which could lead to significant efficiency improvements in hybrids and other vehicles with electric powertrains.”

“Brief presentation on Toyota’s newly developed silicon carbide (SiC) power semiconductor for use in automotive power control units.”

Categories: Bus, Toyota


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8 Comments on "Toyota To Test SiC Semiconductors In Camry Hybrid, Fuel Cell Bus"

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That’s great! Come on Toyota, drop the fuel cell nonsense. We need you back in the game solving problems and contributing to the electrification of our light duty fleet.

Yes they kind of have to choose between Hara-Kiri on Hydrogen or Money Money on EV. They could make an excellent ev for sure and they could also integrate their ultra efficient and compact direct free piston generator as a Rex. It is up to them to decide.

This is quite obviously a great technology advance, with actual junction voltage drops of around 1/2 a volt, peak drops of only 1 1/2 volts, and a figure-of-merit of 10 times that of Silicon devices, 1200 volt withstand, 125 degree centigrate operating temperature, along with only around 10 PF junction capacitance, mean all power equipment makers will be converting to this over the next few years since the economies are so compelling.

Toyota may be the first to officially commit to this technology, but I would think we would soon see Silicon Carbide devices in Solar Inverters, variable speed windmills (and of course PWM drives), and of course in almost all hybrids and BEV’s.

The higher junction temperatures allowable (up to supposedly 200 degrees C) may allow passive heat sink, or at least non-refrigerated cooling solutions.

It will be interesting to see if high temperature batteries also will be available on the marketplace allowing somewhat faster, more energy efficient charging, without having to ‘waste’ energy on cooling kilowatts.

Yeah, this is what it’s all about EV, better efficiency.
Toyota has the power to be the leader, just don’t understand their choice of avoiding all electric.

Power semiconductors really have been an unsung hero in the EV and green energy businesses. They’ve become much more efficient and much cheaper.

IMHO this looks like Toyota is just tweaking their tired old hybrid tech. What is going to happen when these SiC electronics become the norm in BEV?

EV makers will license the tech from Toyota, and Toyota will make boatloads of money.

Seems that Toyota got more mileage out of their Synergy Drive.

I’m not sure how much of this is License-able. Many semiconductor firms are developing this technology, regardless of what TOyota does or doesn’t do.