An Inter-turn Fault tolerant current control of a Five-Phase Servo Motor Based on angle-wise subdivision modeling

Field-oriented control (FOC) is a prevalent control philosophy and has been widely accepted in the servo motor for robotics. The use of a five-phase permanent magnet synchronous motor (PMSM) enables the robot to operate with greater power density and higher reliability. Under single-phase open-circuit fault (OCF), the neutral voltage (NV) of the motor fluctuates over the midpoint of the DC bus, and many methods have been presented to tackle this problem by far. Unfortunately, the current fluctuation stemming from the NV issue remains, and it can be even more severe under the inter-turn short circuit, a case in which the motor suffers time-variant disturbances. To this end, an angle-wise subdivision modeling method is proposed which divides the time-variant disturbances into multiple subdivisions, and each subdivision can be viewed as a linear system, as such the conventional PI controller can still be available. Experimental results verify the effectiveness of the proposed method.