Fault Tolerant Control for PMSM Position Measurement Failure in CMG

Control Moment Gyroscope (CMG) is the core part of the spacecraft which is in charge of rapid attitude maneuvering. Slip ring is the important part of CMG which is responsible for continuous electrical signal transporting from wheel to gimbal. Interruption of slip ring may cause the failure of position measurement of gimbal which will suddenly lead the gimbal of CMG enter into a sensorless PMSM control. This will further lead to a burst disordered operation of CMG and even impact the attitude control of spacecraft. In stage of low speed control of PMSM in gimbal, open loop control has been the only choice for sensorless control without changing the original design. Aimed at operating with a smooth transition from closed loop to open loop of PMSM, rapid diagnosis of temporary position measurement failure incorporates with stator and rotor field direction adjustment control strategy are suggested. With this method, the safety of the satellite has been assured when CMG encountered the temporary of gimbal position measurement failure.