Current Sensor Fault-Tolerant Control Strategy for Encoderless PMSM Drives Based on Single Sliding Mode Observer

In encoderless field-oriented-controlled permanent magnet synchronous motor (PMSM) drives, current sensors may malfunction in harsh working environments. A current sensor fault-tolerant control (FTC) strategy with a single sliding mode observer (SMO) is proposed in this article, which can achieve both phase current error construction and rotor position estimation. This strategy can simplify the system structure and reduce the FTC algorithm complexity. By utilizing the current error construction module, the estimated current error can be obtained from the healthy current sensor. The parameter design of the construction module is investigated to improve the performance. The stability and the convergence rate of the observer can be ensured by selecting appropriate sliding mode parameters. As the proposed current error construction module is independent of motor parameters and the SMO is also less affected by the motor parameter variation, the proposed FTC strategy owns satisfactory robustness. Finally, the effectiveness of the proposed scheme is verified by experiments on a 2.2-kW PMSM drive platform.