This article proposes a single-motor-current feedback resonance suppression method for LCL-equipped high-speed permanent-magnet synchronous motor drives based on capacitively coupled active damper. The proposed method does not require any additional sensors or high-bandwidth current controllers, and an adaptive controller is designed to dynamically adjust the feedback gain. Compared with the active damping methods, the proposed method not only allows the filter resonant frequency to be higher than the Nyquist frequency, but also has strong parameter robustness. Compared with the existing active damper control method, the number of current sensors is reduced by 50%. In addition, thanks to the low harmonic characteristics of the motor current, the output voltage of the damper in the proposed method can be greatly reduced, which helps reduce the damper dc-link voltage from 30% of the inverter to 5%. The low dc-link voltage helps reduce the power loss and makes it possible to use low-voltage mosfets to construct the high-frequency damper. The experimental results of a 3-kW 12-kr/min (1000 Hz) test motor verify the proposed method.
