Multiphase variable speed electric drives are employed in applications where the reduction in the total power per phase and the highest level of overall system reliability is required. Most of the literature on five-phase induction motor (IM) drive deals with field oriented control, direct torque control, and other non-linear control such as backstepping method. This study deals with the theoretical concept and experimental implementation of indirect rotor flux oriented control (IRFOC) and backstepping control (BSC) of a five-phase IM drive. A comprehensive comparison is done between the most popular IRFOC and non-linear BSC. Backstepping control offers high performance in both steady state and transient operations even in the presence of parameters variations. However, this strategy (BSC) allows the synthesis of the speed and the flux control for a five-phase IM, nevertheless this strategy is asymptotically stable in the context of Lyapunov. The comparison is done using experimental approach. The two control approaches are compared in different terms such as their stability proprieties, achievable dynamic performances, online computational effort, the possibilities of controller design and the complexity of their implementation. 7 Highlights † General concept of modelling and control of the ensemble five-phase motor and inverter. † Indirect rotor flux oriented control of a five-phase induction. † Non-linear Backstepping control of a five-phase IM. † Experimental validation of the proposed methods.

The present paper is concerned with introducing an effective direct power control (DPC) approach for a sensor-less doubly fed induction generator (DFIG). The derivation of the proposed DPC approach is performed in a systematic manner in which the design of the rotor current controllers is well analyzed, which clarifies the real base of the control system as when and why it works properly. The operation of the proposed DPC approach is based on the stator voltage-oriented control principle in which the stator voltage is aligned with the quadrature axis of the rotating reference frame. To obtain maximum generation efficiency, the reactive power reference value is derived based on a loss minimization criterion (LMC) that is described and analyzed in detail. To enhance the robustness of the control system, an effective rotor position estimator is proposed that is robust against the system uncertainties, such as the parameters’ variation. To validate the effectiveness of the proposed sensor-less DPC approach, the DFIG dynamic performance is tested for a wide range of operating speeds. The obtained results confirm and emphasize the feasibility of the proposed control approach and its LMC methodology in improving the generation efficiency and in obtaining high dynamic performance from the DFIG.

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The paper proposes Direct Torque Control (DTC) of a five-phase induction motor drive with reduced torque ripple. The method presented here is the DTC Backstepping based on the classic DTC working with a constant switching frequency of the inverter. Another remarkable aspect is the complexity of the method proposed, both in the control unit of the inverter and in the number of correctors necessary for the control of the torque. The selection table and hysteresis have been eliminated. This method significantly improves the torque and flux oscillations and improves the dynamics of the drive by making it less sensitive to load torque disturbances. The proposed method is developed and designed using Matlab/SIMULINK to show the eectiveness and performances of the DTC-Backstepping.