Four-switch three-phase inverter fed IM drives under predictive control strategies: A comparative study

In recent years, the progress of power electronics converters and microprocessors has enabled the implementation of advanced control strategies in AC machine drives. This article deals with a comparative study of the performance of the four-switch three-phase inverter (B4) fed induction motor (IM) drive under predictive torque and flux control strategies (PTC and PFC). The B4 inverter is the reduced structure of the fault-tolerant six-switch inverter (B6) following a fault affecting one leg. First, the IM drive performance under different values of the flux weighting factor of the PTC strategy is investigated. Then, the reliability of the drive following the reconfiguration from B6 to post-fault-tolerant B4 inverter is analyzed, without structural modification of the control laws. The comparative study focuses on the investigation of the steady-state behavior of the drive under two PTC strategies that differ by their weighting factors and the PFC, with emphasis on three criteria namely: (i) the average switching frequency, (ii) the average total harmonic distortion, and (iii) the average switching loss factor. Moreover, the robustness of the drive against resistances variation and against load torque perturbation is tested by simulations. An experimental validation of the steady-state behavior is also carried out using the dSPACE DS1104 platform.