High-Voltage Power System for Hybrid Electric Aircraft Propulsion

Innovators at NASA’s Glenn Research Center have developed a variable-frequency, alternating current (AC) power system to enable turbo-electric and hybrid electric propulsion. Glenn’s technology uses double-fed electric machines and a high-voltage, variable-frequency power system to significantly decrease (by 85%) the weight of an aircraft’s power electronics for turbo-electric propulsion, while still providing high specific power and variable thrust. To provide a safe system, the lightweight electric machines operate at high frequency, allowing fast detection and clearance of faults without requiring switchgear that interrupts the current. This design also reduces the protection system’s weight, while improving reliability by minimizing fault energy and collateral damage potential. In addition, the system permits either sub-synchronous or super-synchronous operation relative to throttle position, without having to adjust turbine settings.