Multiphase converters are usually composed of several standard 3-phase converters containing Intelligent Power Modules (IPMs). These 3-phase IPM have 6 sets of IGBT-diode pairs having similar switching properties. However, switching properties and/or forward voltage drops of different IPMs can vary significantly, causing an asymmetry in the converter's output. This paper proposes a generic method for identifying these converter asymmetries and estimates an average non-linear voltage drop across each converter leg. These identified voltage drops are experimentally evaluated on a 9-phase multiphase electrical machine (MPEM) supplied from three 3-phase converters, decomposed into four vector spaces and a zero component. With non-linearity correction, the fundamental components of vector spaces 1 and 3 are improved significantly while reducing the rest of the harmonic components.

A multiphase induction machine model using vector space decomposition provides insights into many space harmonics through decoupled reference frames. These decoupled reference frames host specific space vectors related to particular space harmonics. Based on the physical winding configuration, these vector spaces can be excited independently or simultaneously for the production of torque. Each torque-producing vector space generates a unique number of magnetic pole pairs and has independent torque-slip characteristics. In most literature, the transition between these magnetic pole pairs is achieved by magnetizing a desired vector space and then performing the torque transition. This approach results in beat oscillations due to interference between magnetized vector spaces. This paper proposes a solution that eliminates these beat oscillations during magnetic pole-pair transition while optimizing the stator current peaks. The effectiveness of this synchronized phase- pole modulation solution is experimentally verified on a 9-phase induction machine in comparison to the standard magnetic pole-pair transition methods.

Pole-phase changing (PPC) induction machines (IMs) can achieve improved efficiency as well as wider torque-speed range compared to their fixed pole-phase counterparts. In this paper, a 4-pole IM is designed and evaluated in terms of its pole-phase changing performance.

Today, multiphase electric machinery is considered in automotive traction applications. Some multiphase machine topologies also enable the possibility to change the pole and/or phase number during operation, an option which can be of benefit thanks to the large speed range that an electric machine for traction applications typically operates with. In this paper, an analytical model of the current dynamics for the wound independently-controlled stator coils (WICSC) and the intelligent stator cage drive (ISCAD) machines is presented. The model, based on setting up a permeance network in the stator and rotor and a rotor-angle dependent connection between the two networks, allows for predicting current transients during pole and phase changes. Thus, it is suitable for the design of control methods exploiting both the multiphase nature of the machine as well as performing pole-number changes during operation. The presented model is validated by comparing results from a corresponding finite-element based model of a WICSC machine during a pole change.

This paper presents a preliminary electromagnetic sizing algorithm for double-rotor axial-flux induction machines (DR-AFIMs). The proposed algorithm is based on a geometrical approach and limits the use of empirical factors and past experience. The sizing equations for all the main geometrical and operational machine parameters are derived and a concise outline of the electromagnetic sizing algorithm is provided. The efficacy of the implemented algorithm is validated using finiteelement DR-AFIM models. The achievement of the targeted specifications in the preliminary DR-AFIM designs is proven and demonstrated.

In this paper, a novel induction machine topology with wound, independently-controlled stator coils is presented. The introduced configuration of the stator-winding enables the individual energization and control of the coils in each stator slot. Therefore, the possibility of changing the number of poles and active phases in the stator winding during operation is explored in this study.

This paper presents a Pareto-optimality-based optimization methodology suitable for the design of electrical motors in automotive applications. The proposed many-objective evolutionary algorithm is utilized in this study case for the optimization of an interior permanent-magnet (IPM) synchronous motor and an induction motor (IM), considering as criteria the motors' torque capability, efficiency as well as torque density. Finite-element (FE) models of the investigated motor topologies are developed and incorporated in the optimization process in order to ensure an accurate estimation of their electromagnetic performance. The attainment of the targeted specifications by the final optimal designs validates the efficacy of the implemented optimization algorithm.