This paper proposes a gain optimization method for an active damping controller in a mono-inverter dual parallel permanent magnet synchronous motors drive system. In this system, two motors are connected in parallel to a single inverter with one motor operating as the master motor under vector control and the other as the slave motor in an open-loop configuration. The inherent coupling between the two motors causes torque oscillations in the slave motor under load torque differences or rotor position deviations, leading to system instability. An active damping controller is proposed to suppress torque oscillations and stabilize the operation of the slave motor. However, the gain of the controller needs to be adjusted experimentally, which complicates the implementation of the method. This paper introduces a systematic approach to designing the controller gain based on stability analysis and the least squares method. The feasibility and effectiveness of the proposed method are validated numerically and experimentally using two permanent magnet synchronous motors.
