This paper provides a guide to design multi-phase fractional slot concentrated windings (FSCW) using the star of slots. Even though the star of slots method works in general, it has been mostly applied to three- phase machines. In this paper, the star of slots theory is revisited and applied to multi-phase windings. A computer program in Python is developed to automate the calculations. The inputs for the winding design are: the slot number, the pole-pair number and the layers. From them, symmetry conditions are tested before drawing the star of slots and assigning the coil sides in the slots to phases. Important winding characteristics, such as the winding factor for the fundamental and harmonic waves are calculated. The program is tested on examples for FSCWs with five and seven phases.

This paper investigates the control algorithm of five phase permanent magnet synchronous motor using Volt-Second balance principle to generate the switching signals for Voltage Source Inverter (VSI). The five-phase IPMSM is modelled as two 3 phase PMSM motors mechanically coupled. The results show that the scheme that is used to control the first and third harmonics of the machine can produce desired dynamics for the current control and guarantees balanced current sharing between the winding.

This paper summarizes the performance analysis done on a five-phase self-excited synchronous machine, which has been designed for traction application in a hybrid electric vehicle. The machine design is briefly discussed and the output results are then presented from simulation in ANSYS Electronics Desktop. Some of the most significant machine outputs are then analyzed with respect to certain machine parameters. An efficient method of machine testing based on digital twins is also discussed.

Rotor position transducerless control (self-sensing) techniques emerge as promising software-based sensor replacement strategy for redundancy concepts in industrial applications. Interior permanent magnet synchronous machine (IPMSM) drives offer the required physical properties for effective online motion state estimation. At low speed range including standstill, high frequency signal injection (HFSI)-based saliency-tracking methods estimate the rotor position solely utilizing terminal machine properties. However, implementation of HFSI is challenging and highly reliant on the given machine design. Load dependent non-linear phenomena can have detrimental effects on estimation accuracy and hence the required robustness, limiting the use in fail-operational safety-relevant applications. This paper proposes a modified implementation strategy for using HFSI as part of a position sensor redundancy concept for highly utilized IPMSM drives. A simple identification procedure is presented, isolating static position estimation errors. Experimental results confirm effective compensation of satuartion-induced errors, maximizing the fault-detection and fault-compensation capabilities of the proposed strategy even under heavy load conditions.

Modulation of two-level multiphase voltage-source inverters (VSIs) provides an increased number of degrees of freedom when compared to three-phase inverters. Choosing a modulation scheme for an application is a critical task and should be evaluated carefully, especially in multiphase inverters. Calculation of performance indicators for the overall harmonic content, like the harmonic distortion factors (HDF) or total harmonic distortion (THD) of the output have already been presented in literature. This research presents analytic calculation of voltage harmonics generated by the standard space vector modulation schemes (continuous and discontinuous) for multiphase drives with an odd number of phases. Therefore complete knowledge of the output voltage spectrum is gained, which e.g. enables the analysis of frequency dependent loads. Moreover calculated voltage harmonics are linked to the well-established HDFs.

During transient process, it may take plenty of steps for PMSM to reach the reference torque and flux linkage. Multistep model predictive torque and flux control (MPTC) can select the best sequence of voltage vectors from the initial state to the reference state to achieve the fastest torque response. However, the computation burden is a significant challenge for real-time implementation. This paper proposes a novel fast-response MPTC strategy for PMSM drives. The reference torque is converted to flux linkage in d-axis and q-axis to eliminate the weighting factor in cost function. During the transient process, Pontryagin's maximum principle is used to design minimum-time flux linkage trajectories from the initial state to the reference state. In each control period, along the reference flux linkage trajectories, one-step MPTC is used to select the best voltage vector. The computational burden and dynamic performance of the proposed method are verified by experiments.

This paper presents an analysis of iron losses for an inverter-fed permanent synchronous electric machine. The iron loss computation is based on the coupling between an analytical inverter model and a 2D finite element simulation. For theoretical explanation of the considered effects the magneto motive force of the machine with non-sinusoidal supply is derived. These impacts are analyzed in detail for one operating point, while using two different iron loss models. It is shown that the iron losses are much higher with inverter supply caused by high harmonic flux content in the rotor finite elements. At the end the iron losses for the whole operating range are computed to verify the single point calculation.

This paper deals with the identification and analysis of an electric drive configuration at system level. In terms of efficiency and power density, the investigation is intended to enable a statement whether the ideal electric motor application is a direct drive or a combination with a gearbox in the drive gondola of a Do 128-6 aircraft. In this research, seven versions of electrical drive combinations are presented and examined based on analytical calculations and software simulations. First, the designs of permanent magnet motors (PM) with concentrated windings are analyzed with the FEM-based engineering tool ANSYS Maxwell 2D. A common 12-teeth/10-pole winding topology is compared to a 12-teeth/14-pole winding topology designed with flux barriers in the stator. After that, the gearbox is evaluated with GAP (a gearbox design program). Furthermore, the mechanical power is considered because it depends on the aerodynamic characteristics of the aircraft. The results show that the geared drives are well suited for this application.

This paper presents and discusses the state of the art in high-speed electrical machines. It is connected to a project in which there is a challenge to design a high-speed turbo generator with a rated speed of 50000 rpm and a continuous power of 700 kW for usage in aircraft. For this reason, typical electrical machines are compared in order to examine their advantages and disadvantages in identifying the best topology and in fulfilling given requirements. Finally, FEM results provide an indication of the feasibility of fulfilling project requirements.

This paper presents a design of a two-pole high voltage induction machine with concentrated coils wound on twelve stator teeth. Using a combined wye-delta winding a magnetomotive force distribution with a low content of space harmonics is created. For suppression of still existing undesirable slot harmonics, a special interconnection of rotor bars is examined. In addition to the design with a finite element method, an analytical approach was made in order to verify the obtained results. Particular attention is paid to the following points: - Reduction of installation space - Reduction of production costs - Evaluation of currents and magnetic fields.

This paper presents a new three phase single tooth concentrated winding topology. With the new locally asymmetric configuration, each individual harmonic can be addressed, so operations with any number of pairs of poles are possible. Furthermore, the new arrangement of single coils presented here allows variations of winding characteristics such as winding factor, spectrum of the magnetomotive force etc. Using a combination of this winding with a squirrel-cage rotor shape a robust and reasonable solution for implementation in safety-critical but cost effective automotive applications, especially in case of strictly limited axial machine dimension. In this paper three different winding layouts are compared on a very compact installation space, specified for a 30 kW starter-generator.

This paper applies deadbeat-direct torque and flux control (DB-DTFC) to minimize machine and inverter losses in synchronous reluctance drives each single switching period. Flux linkage-based loss models for machine and inverter considering nonlinear effects such as cross-saturation and temperature changes are experimentally evaluated. Loss minimizing capabilities are demonstrated comparing three different control strategies. It is shown experimentally that incorporating inverter losses into the control algorithm and minimizing losses of machine and inverter instead of only considering machine losses leads to a reduction of total losses.

This paper investigates the characterization of three-phase EMI filter using S-parameters and the use of sequence model to fully describe the high frequency behavior. Characterization of three-phase EMI filter helps to understand the influence of real filter on overall EMI performance and provides information for filter selection or design. The characterization is divided into two types: component level or system level, which can be chosen to use according to design conditions. S-parameters are chosen as network parameters to characterize because of the convenience to measure them in high frequency range. Beside circuitry model of filter, sequence model of filter is proposed to better describe the attenuation and conversion between different forms of noise, which improves the understanding towards filter behavior compared to traditional separation of common and differential mode noise. Corresponding equations are provided to obtain parameters in the sequence model. At the end, the predictions of insertion loss and energy transfer ratio which represent the grade of mode conversion based on sequence model are shown and compared with results from conventional measurement method.

In this paper two arrangements for reducing the power losses in power electronics of an electric drive are verified in a test bench. Firstly, it is proven that the chip area of the transistors and diodes has an impact on the switching losses and has to be adapted to the requirements of the electric machine in order to operate at maximum efficiency. Secondly, it is demonstrated that a variation of the conducting chip area of the IGBTs during operation also leads to a reduction of the switching losses. This additional degree of freedom can be used to optimize the total power losses of the power electronics with the effect of higher energy efficiency especially at partial load.