Fault tolerant IPMS motor drive based on adaptive backstepping observer with unknown stator resistance

This work considers the problem of designing a fault tolerant system for IPMS motor drive subject to current sensor fault. To achieve this goal, two control strategies are considered. The first is based on field oriented control and a developed adaptive backstepping observer which simultaneously are used in the case of fault-free. The second approach proposed is concerned with fault tolerant strategy based on observer for faulty conditions. Stator resistance as possible source of system uncertainty is taken into account under different operating conditions. Current sensors failures are detected and observer based on adaptive backstepping approach is used to estimate currents and stator resistance. The nonlinear observer stability study based on the Lyapunov theory guarantees the stability and convergence of the estimated quantities, if the appropriate adaptation laws are designed and persistency of excitation condition is satisfied. In our control approach, references of d-q axis currents are generated on the basis of maximum power factor per ampere control scheme related to IPMSM drive. The complete proposed scheme is simulated using MATLAB/Simulink software. Simulation is made to illustrate the proposed strategy.