• 2015 Toyota Camry Hybrid SiC Prototype

Toyota’s Hybrid Synergy Drive is already one of the most advanced gasoline-electric powertrains on the planet, but the Japanese automaker is looking to squeeze even more technology into its high-efficiency vehicles, with the use of silicon carbide (SiC) power semiconductors that were developed in collaboration by Toyota, Denso and Toyota Central R&D Labs.

According to Toyota, the semiconductors used in today’s hybrids and electric vehicles have more electrical resistance than SiC semiconductors, accounting for an electric energy loss of around 20 percent, so switching to the more-efficient SiC semiconductors should result in improved performance from the electric drive components. To find out exactly what kind of improvement that would be, Toyota will begin a year-long test (starting this month in Japan) of a Toyota Camry Hybrid prototype that utilizes a power control unit (PCU) equipped with these new semiconductors.

While Toyota has not revealed when it plans to start using them in production vehicles, it doesn’t seem like it will be ready in time for use in the next-gen Toyota Prius expected to debut later this year.

Click past the jump to read more about the 2015 Toyota Camry Hybrid SiC Prototype.


The exterior design of this prototype is based on the JDM-spec Toyota Camry, and aside from the prototype drivetrain and the obvious decals, there doesn’t appear to be any changes made to the test vehicle. That being said, the current Hybrid Synergy Drive is now used in more than a dozen Toyota and Lexus hybrid vehicles, so if it does in fact become a next-generation hybrid or EV system, there are plenty of applications in which it could potentially be used.


Like the exterior, this prototype simply uses the same interior components as the standard JDM Camry, but Toyota has not provided any interior shots of the car.


In terms of engine, electric drive components and batteries, it would seem that this prototype is essentially a carryover from the current production version, but the important part is the new PCU that uses the newly developed SiC semiconductors. The PCU is used in all facets of hybrid and EV driving, including transferring power back and forth between the battery and the electric motors during normal operation and brake regeneration. During the testing phase of the prototype, the PCU receives SiC semiconductors for its voltage step-up converter and the power inverter used to control the electric motor, and real-world road tests will help provide Toyota with key data pertaining to the PCU and driving conditions of the car.

Although the prototype in this case is based on a hybrid, the data collected will also be used to advance the technology of electric vehicles.


There is no indication as to how much the new SiC semiconductors would affect pricing for future hybrids and electric vehicles, but like any new tech, there could be a slightly higher price that factors in engineering and research and development costs.


Hyundai Prius Fighter

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Hyundai appears ready to finally give Toyota some competition in the hybrid segment, with a new hatchback — due out later next year — that will go head-to-head with the next-gen Prius. Although there are few details known about this car, recent spy shots revealed that it will sport a similar aero-tuned body as the Prius, and it will likely be a little larger than the Hyundai Elantra GT hatchback. If it uses a more-efficient version of the hybrid system used in the Sonata Hybrid, it’s very likely that Hyundai could give its new model highly competitive fuel economy and EV range.

2016 Chevrolet Volt

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Chevrolet Volt

Introduced at the 2015 Detroit Auto Show, the 2016 Chevrolet Volt builds upon the first-gen model with an updated powertrain that’s lighter, more powerful and more efficient. The new Volt will have an EV driving range of 50 miles (a 12-mile improvement over the 2015 MY) and a total range of more than 400 miles. The 2016 Chevrolet Volt goes on sale this fall.


It has yet to be seen how Toyota plans to incorporate these advanced SiC power semiconductors into its productions models, but it will surely help make its already-class-leading hybrid vehicles even better while establishing some added EV credibility as well. As progressive as Toyota was with its gasoline-electric hybrid powertrains in the late 1990s and early 2000s, Toyota is lagging behind the competition a bit when it comes to full electric vehicles, and this new semiconductor has the potential to give Toyota the improved technology to create an EV as dominant as its hybrid powertrains have been.

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Jeffrey N. Ross
Jeffrey N. Ross
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Press Release

Using a "Camry" hybrid prototype and a fuel cell bus, Toyota Motor Corporation 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.

2015 Toyota Camry Hybrid SiC Prototype Drivetrain
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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.
Test vehicles and period

2015 Toyota Camry Hybrid SiC Prototype
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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.

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