Abstract The main objective of this two parts state of the art paper called 'Recent Advances in the Design, Modeling and Control of Multiphase Machines' is to present latest contributions in the multiphase machines' field. The first part of the work focuses on the recent progress in the design, modelling and control while the drive is in healthy operation. This second part presents relevant contributions in two not analyzed fields. The first is in relation with the use of the additional degrees of freedom of multiphase machines and the exploitation of their fault-tolerant capabilities without adding extra hardware. The second one analyzes multiphase generation, especially in grid-connected wind energy conversion systems and stand-alone applications. Recent progresses are shown and open challenges and future research directions are discussed.Index Terms Multiphase machines, motor drive control in faulty operation modes, generation systems. Manuscript

Abstract Multiphase machines are well recognized as an attractive alternative to conventional three-phase ones in a number of applications where high overall system reliability and reduction in the total power per phase are required. The pace of developments in the field has accelerated in the last few years, and substantial knowledge has been recently generated. The main objective of the two parts' survey named 'Recent Advances in the Design, Modeling and Control of Multiphase Machines' is to present relevant contributions to encourage and guide new advances and developments in the field. More specifically, the part 1 of the work analyzes the recent progress in the design, modelling and control, including healthy operation of multiphase motor drives, and discusses open challenges and future research directions in the area.Index Terms Multiphase machines, design, modeling, parameter estimation, motor drive control in normal operation mode. Manuscript

Abstract One of the most attractive features of multiphase machines is the fault-tolerant capability due to the higher number of phases. Different post-fault control strategies based on hysteresis, PI-resonant and predictive techniques have been recently proposed. They all proved their capabilities to withstand fault situations and to preserve the fundamental component of the air-gap field, while achieving minimum losses, maximum torque per-ampere and reducing torque vibrations. Nonetheless, due to their recent introduction, no thorough study has yet appeared comparing the performance of these controllers. In this paper two open-phase fault-tolerant control schemes are experimentally compared in a real five-phase induction machine. The controllers being compared are based on PI-resonant and predictive control techniques, respectively. The experiments include pre-and postfault situations. Obtained results show that both control methods offer nearly the same performance. When compared, predictive control provides faster control response and superior performance at low speed operation but is found to be less resilient to fault detection delays and to have higher current ripple. Regarding the controller implementation, it is shown that the transition from preto post-fault operation involves modelling the non-linear effects observed when an open-phase fault occurs for the predictive controller, and the proper retuning of the PI trackers for the PIresonant controller, in order to ensure post-fault operation.

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The most serious and recent competitor to the standard field oriented control (FOC) for induction motors (IM) is the finite control set model predictive control (FCS-MPC). Nevertheless, the extension to multiphase drives faces the impossibility to simultaneously regulate the flux/torque and the secondary current components (typically termed 𝒙-𝒚 in literature). The application of a single switching state during the whole sampling period inevitably implies the appearance of 𝒙-𝒚 voltage/currents that increase the system losses and deteriorate the power quality. These circulating currents become intolerably high as the per unit 𝒙-𝒚 impedance and the switching frequency diminish. Aiming to overcome this limitation, this work suggests the integration of virtual voltage vectors (VVs) into the FCS-MPC structure. The VVs ensure null 𝒙-𝒚 voltages on average during the sampling period and the MPC approach selects the most suitable VV to fulfill the flux/torque requirements. The experimental results for a six-phase case study compare the standard FCS-MPC with the suggested method, confirming that the VVbased MPC maintains the flux/torque regulation and successfully improves the power quality and efficiency.