Sensor-fault tolerant control of PMSM in flux-weakening operation using LKF observer

The reliability and high efficiency of the power electronic drives used in electric vehicles is an essential requirement. To achieve high efficiency for the electrical drive system permanent magnet synchronous motors (PMSM) are employed. At high speed operation of the electric vehicles the electrical motors usually operate in the so called flux-weakening operation mode. When the control of the PMSM in flux-weakening operation mode is lost (due to untrustworthy position or current feedback signal) high voltage will appear in the DC-link which can damage the power switches, the battery and the auxiliary circuits connected to the DC-link. A method, based on linear Kalman filter, to detect the feedback signal failure and to maintain the DC-link voltage in the normal range is presented in the paper. The proposed method is investigated through experimental test.