A High-Frequency GaN-Based Motor Drive for Aircraft Electromechanical Actuators

To achieve superior dynamic response performance for aircraft electromechanical actuators (EMAs), high speed, low inductance, or multipole permanent magnet synchronous motors (PMSMs) prove to be ideal candidates. This necessitates a high-switching frequency for the motor drives. Cascode gallium nitride (GaN) devices present themselves as highly appealing for this specific application due to their high-switching frequency, low losses, and ability to operate at high temperatures. However, due to the intricate device structure and the high rates of change of voltage (dv/dt) and current (di/dt), GaN-based motor drives are more susceptible to oscillations, leading to electromagnetic interference (EMI) issues. This article presents a cascode GaN-based motor drive operating at a 100-kHz switching frequency for aircraft EMAs. A mathematical model is established to elucidate the mechanisms behind the turn-on dv/dt effect and turn-off di/dt effect of the cascode GaN-based inverter, shedding light on the occurrence of oscillations. The impact of gate driver parameters on the dv/dt and di/dt effects is thoroughly examined. Furthermore, a design method for RC snubber parameters is proposed to further alleviate the turn-off di/dt effect. Finally, experimental validations are conducted to confirm the efficacy of the proposed design methods and the performance of the high-frequency GaN-based motor drive.