Page 62 - NEW Armstrong Book - 2

Power Technologies in EVs
D
esigners’ efforts to improve energy-conversion efficiency in electric and hybrid vehicles
considered to be the major prereq- uisite for full EV adoption. One way to reduce costs and increase system effi- ciency is to integrate the powertrain. The biggest challenge here is the cost of EV batteries, which is coming down but proportionally still accounts for a huge percentage of the overall cost of a battery electric vehicle. SiC adoption could make a difference, both reduc- ing the cost and increasing the perfor- mance of EV batteries.
SiC for EVs
The benefits of using SiC in an EV are “efficiency, efficiency, and efficiency,” said Stephen Lambert, head of electri- fication at McLaren Applied. “While you can swap silicon IGBT devices for SiC devices and see an efficiency benefit, the most benefits come from optimizing
By Maurizio Di Paolo Emilio
the whole drivetrain around the benefits of SiC.”
A more efficient drivetrain will also take less time to recharge for a given range. “For example, if you utilize the higher switching frequencies of SiC, you will lose a bit of that efficiency gain,” said Lambert. “However, you will then be able to optimize the motor, making it a higher-speed, lower-torque motor but with higher overall efficiency — more than offsetting any disadvantage of higher switching frequencies.
“Smaller and lighter motors, even higher-speed ones, will also then end up cheaper,” he said. “At high volumes, the cost of the motor will lean toward raw materials. Higher switching fre- quencies also allow you to reduce the size of your DC-link capacitor, reducing
are oriented toward devices equipped with compact packaging and assem- bly of high-thermal–reliability power electronics modules with reduced switching losses. There are many tech parameters involved, including power level, conversion efficiency, operating temperature in the vehicle powertrain system, thermal energy dissipation capacity, and system package. SiC tech- nology provides superior switching and improved thermal performance com- pared with similar silicon devices. This translates into improved efficiency for electric vehicles.
The EV market still faces two sig- nificant challenges: cost and driving range. Eliminating range anxiety is
MCLAREN POWERTRAIN (SOURCE: MCLAREN APPLIED)
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ASPENCORE GUIDE TO SILICON CARBIDE