Phase Winding Research Articles

Multi-Harmonic Currents Control Strategy for Five-Phase Permanent Magnet Machine with non-sinusoidal back-EMF

This paper describes an optimal torque per peak current control method for a five-phase permanent magnet (PM) machine considering both 3rd and 5th harmonic currents. These optimal ratios to the fundamental component are analytically derived to maximize the output torque. It is found that except for the 3rd harmonic current contributing to the output torque, the 5th harmonic current can also produce the additional positive torque. However, the 5th harmonic is zero sequence component for the five-phase machines, which does not exist in the phase windings. Hence, the neutral point is required to connect the middle point of the DC link capacitors for constructing flowing path. The conventional vector space decomposition (VSD) control is extended to zero sequence sub-plane, which can quantitatively control 5th harmonic current. For a prototype five-phase PM machine, the average torque can be increased by 21.4% with 3rd harmonic current injection. Meanwhile, 10.7% additional positive torque is achieved together with 3rd and 5th harmonic injection. The torque ripple remains similar to that without harmonics injection. Finally, the experiments are given to demonstrate the theoretical analysis.

Novel modelling method based on winding sub‐element of direct‐drive permanent magnet synchronous motor

Owing to its many benefits, including convenient and short computing time, the analytical model (AM) is widely used in the performance analyse of the permanent magnet synchronous motor (PMSM). The existing analytical models based on phase winding cannot sufficiently speculate about the contribution of the coil to the performances of direct-drive PMSM (DDPMSM) with series coils and multiple branches. Hence, in this work, a novel AM for the DDPMSM is proposed. This model, which is based on the winding sub-element, can analyse the influence of coil on motor performance. First, the structure and key parameters of the DDPMSM are reported. Second, an inductance matrix, which considers the spatial disposition of coils and the characteristics of large self-inductance and small mutual inductance, is constructed. Then, the influence of the coil on motor performance is analysed based on the proposed AM. Finally, the results of AM, finite-element model and experiment are compared. The results validate the correctness of the proposed AM. Furthermore, the proposed AM can speculate about the contribution of a coil in the DDPMSM performances with satisfactory accuracy.

CHARACTERISTICS OF A CYLINDRICAL INDUCTOR OF A ROTATING MAGNETIC FIELD FOR TECHNOLOGICAL PURPOSES WHEN IT IS POWERED FROM THE MAINS AT A GIVEN VOLTAGE

Introduction. A computational analysis of the characteristics of an inductor of a rotating magnetic field for technological purposes is presented. The design of its stator is borrowed from a three-phase induction motor. The cylindrical cavity inside the stator is occupied by a working chamber into which a granular or liquid processed substance is loaded. The processing is carried out with elongated ferromagnetic elements moving with a magnetic field. Problem. The purpose of the article is a study of the electromagnetic, phase, and energy characteristics of an inductor at its operation under load mode with a given voltage of the stator winding. Methodology. The study is performed on the basis of numerical calculations of the magnetic field, taking into account the anisotropy of the low-magnetic medium in the working chamber. Its discrete medium is represented homogeneous with different magnetic permeabilities on mutually perpendicular axes. The technique of transition from the results of the magnetic field calculation to the electric, magnetic, phase and energy parameters of the inductor is given. This is facilitated by the electrical equivalent circuit of the stator phase winding, the equilibrium equation of its electrical quantities, vector diagrams and an iterative method for determining the current at a given voltage. Results. Mutual dependencies of a number of inductor parameters are formed into a family of characteristics exhibiting its properties in an operating mode with a changing load. Characteristics include such quantities as magnetic flux linkage of the stator winding, its current and EMF, phase shifts between them, electromagnetic torque, expended and useful power and its losses, power factor and efficiency. In this article, a feature of this mode is the stability of the stator winding voltage in the inductor. This complements the earlier studies of the inductor in the mode with stabilization of the winding current, which allows to compare these options. On the example of a test sample of an inductor, a number of its characteristics are shown, vector diagrams of its electric and magnetic quantities illustrating their mutual phase shifts are given. Practical value. The presented technique for determining the electric and magnetic quantities of the inductor and their phase relationships, and also the shown family of characteristics can contribute to increasing the design efficiency and improving the inductors of the considered type. The developed technique has the universality property, as it is capable of displaying their various circuit and constructional design parameters.

A Three-Phase Integrated Battery Charger for EVs Based on Six-Phase Open-End Winding Machine

This article presents a new configuration of onboard integrated battery charger for electric vehicles (EVs) using six-phase machine and three-phase ac source. The configuration proposes the utilization of symmetrical six-phase open-end winding machine, twelve-leg inverter, and a dc–dc converter. The charger circuit is constructed by connecting directly the three-phase grid to the middle point of machine's phase winding, where the grid currents split into equal portions and flow in opposite directions, without adding an extra mechanical switch (or relay). From this concept, the proposed system has the advantages of obtaining high-power density with a large value of inductance for grid-side filter during charging and avoiding an electromagnetic torque as well as providing a high fault tolerant capability. Moreover, through proper control strategy, the proposed system is able to operate under unity power factor (UPF) with total harmonic distortion (THD) below 5%. In this article, the possibility of vehicle-to-grid (V2G) mode is also investigated. Detail of the control strategy for charging and V2G are given. Furthermore, simulation and experimental results are provided to validate the theoretical analysis.

Multiphase outflows in post-starburst E+A galaxies - II. A direct connection between the neutral and ionized outflow phases

ABSTRACT Post-starburst E+A galaxies are systems that hosted a powerful starburst that was quenched abruptly. Simulations suggest that these systems provide the missing link between major merger ULIRGs and red and dead ellipticals, where AGN feedback is responsible for the expulsion or destruction of the molecular gas. However, many details remain unresolved and little is known about AGN-driven winds in this short-lived phase. We present spatially resolved IFU spectroscopy with MUSE/VLT of SDSS J124754.95-033738.6, a post-starburst E+A galaxy with a recent starburst that started 70 Myr ago and ended 30 Myr ago, with a peak SFR of $\sim 150\, \mathrm{M_{\odot }\,yr^{ -1}}$. We detect disturbed gas throughout the entire field of view, suggesting triggering by a minor merger. We detect fast-moving multiphased gas clouds, embedded in a double-cone face-on outflow, which are traced by ionized emission lines and neutral NaID emission and absorption lines. We find remarkable similarities between the kinematics, spatial extents, and line luminosities of the ionized and neutral gas phases, and propose a model in which they are part of the same outflowing clouds, which are exposed to both stellar and AGN radiation. Our photoionization model provides consistent ionized line ratios, NaID absorption optical depths and EWs, and dust reddening. Using the model, we estimate, for the first time, the neutral-to-ionized gas mass ratio (about 20), the sodium neutral fraction, and the size of the outflowing clouds. This is one of the best ever observed direct connections between the neutral and ionized outflow phases in AGN.

Associations between Quasi-biennial Oscillation phase, solar wind, geomagnetic activity, and the incidence of acute myocardial infarction.

An increase in the daily rate of acute myocardial infarction (AMI) has been observed during days of geomagnetic storm (GS). However, the analysis of associations between the daily number of AMI and geomagnetic activity (GMA) over longer periods sometimes yields controversial results. The study aimed to detect the complex association between the daily numbers of AMI and weather, the Quasi-biennial Oscillation (QBO) phase, GMA, and solar wind variables. We used data of Kaunas population-based Ischemic Heart Disease Register of residents of Kaunas city (Lithuania) for 2000-2012. The associations between weather and space weather variables and the daily number of AMI were evaluated by applying the multivariate Poisson regression. A higher risk of AMI was positively associated with active-stormy local GMA (rate ratio (RR) = 1.06 (95% CI 1.01-1.10)), solar wind dynamic pressure with a lag of 4days (RR = 1.02 (1.01-1.04) per 1nPa increase), and solar wind speed with a lag of 3-7days (RR = 1.03 (1.01-1.05) per 100km/s increase). A positive association was found between the west QBO phase and the risk of AMI during winter (RR = 1.08 (1.01-1.16)), and a negative association was observed between them during March-November (RR = 0.93 (0.90-0.97)). The risk of AMI positively associated with the GS due to stream interaction regions with a lag of 0-2days during the east QBO phase (RR = 1.10, p = 0.046) and was negatively associated with them during the west QBO phase (RR = 0.82, p = 0.024). These results may help understand the population's sensitivity under different weather and space weather conditions. The QBO phase may modify the effect of GS.

Transverse nonlinear vibration of the eccentric rotor in a 12/8 switched reluctance motor

PurposeTo investigate transverse vibration of the eccentric rotor in a 12/8 poles switched reluctance motor (SRM), a transverse analytical vibration model is built by finite element method (FEM) under the interaction of radial magnetic resultant and vibration displacement. External forces, including radial magnetic resultant and centrifugal force, are also derived in detail, according to the variation of airgap and current and other intermediate parameters with rotation angle.Design/methodology/approachThe transverse vibration response of the eccentric rotor including radial magnetic resultant and vibration displacement is solved by Newmark-β method, after inputting the currents of three phase windings under angle position control strategy. The basic characteristics of radial magnetic resultant and vibration displacement are reflected in time and frequency domain.FindingsThe magnetic resultant vector of the eccentric rotor presents multi-petals star geometric shape. The frequency distribution of magnetic resultant relates to rotation speed, current waveform and the least common multiple of the stator and rotor teeth. However, the frequency distribution of the vibration displacement also relates closely to the first-order critical whirl speed of the rotor. When the rotor is running at certain speeds, it will display superharmonic resonance and show abundant displacement locus.Originality/valueBy using this analytical model and solving process proposed in this paper, the nonlinear coupled vibration response of the eccentric rotor in SRM can be analyzed and discussed rapidly; only the stator’s winding currents obtained by experiment or electromagnetic simulation is needed as input.

Universal momentum-to-real-space mapping of topological singularities

Topological properties of materials are typically presented in momentum space. Here, we demonstrate a universal mapping of topological singularities from momentum to real space. By exciting Dirac-like cones in photonic honeycomb (pseudospin-1/2) and Lieb (pseudospin-1) lattices with vortex beams of topological charge l, optimally aligned with a given pseudospin state s, we directly observe topological charge conversion that follows the rule l → l + 2s. Although the mapping is observed in photonic lattices where pseudospin-orbit interaction takes place, we generalize the theory to show it is the nontrivial Berry phase winding that accounts for the conversion which persists even in systems where angular momentum is not conserved, unveiling its topological origin. Our results have direct impact on other branches of physics and material sciences beyond the 2D photonic platform: equivalent mapping occurs for 3D topological singularities such as Dirac-Weyl synthetic monopoles, achievable in mechanical, acoustic, or ultracold atomic systems, and even with electron beams.

A Hybrid Multilevel Inverter Scheme for Nine-Phase PPMIM Drive by Using Three-Phase Five-Leg Inverters

In pole-phase modulation, the phase order is coming down by pole ratio times in high pole mode, which results in the higher magnitude of spatial harmonics as well as higher torque ripple. In this article, the available three identical voltage-fed windings per effective phase in three-phase 12-pole (3PH-12PO) mode are used to develop the simple multilevel inverter (MLI) configuration for minimizing torque ripple. The proposed MLI scheme is realized with three five-leg inverter modules. Each five-leg inverter module will generate three-level voltage across the phase, thereby resultant voltage seen by each phase winding is five-level voltage in 3PH-12PO mode. This multilevel voltage will improve the torque ripple profile of the motor drive. In addition, the proposed MLI scheme along with phase grouping will enrich the linear modulation range of the pole-phase-modulated induction motor (PPMIM) drive in nine-phase four-pole (9PH-4PO) mode. The switches used to generate a multilevel voltage in 3PH-12PO mode are effectively utilized for blocking the flow of circulating currents. As compared with other conventional nine-phase five-level inverters the proposed five-level inverter requires only 30 switches and it does not require extra clamping diodes/capacitors and extra bidirectional switches for isolating neutrals in 9PH-4PO operation. The validation of proposed MLI scheme is done on a 5-hp nine-phase IM with Ansys Maxwell as well as laboratory prototype for entire modulation range using V/f = constant control.

A Single DC Source-Based Three-Level Inverter Topology for a Four-Pole Open-End Winding Nine-Phase PPMIM Drives

This article proposes a three-level inverter topology for nine-phase pole phase-modulated induction motor (PPMIM) drives by using the two identical voltage profile coils (IVPC) of a four-pole stator winding. In general, the two IVPCs of each phase winding are connected in series, but in this article, these two IVPCs are separated and excited with conventional two-switch inverter legs without disturbing the flux per pole and other machine parameters. The 18 IVPCs of four-pole nine-phase induction motor (IM) are excited with 18 two-switch inverter legs and fed by the same dc source. Each two-switch inverter leg generates the two-level voltage across each IVPC winding, i.e., the resultant voltage seen by the phase winding is a three-level voltage waveform. As compared to conventional nine-phase neutral point and flying capacitor multilevel inverters (MLIs), the requirement of the dc-link magnitude for the proposed topology is reduced by 50%. The nine-phase PPMIM drive is modulated with the carrier-based three-phase space vector pulsewidth modulation in order to enhance the linear modulation range (LMR). The inverter legs associated with two IVPCs per phase in 9-phase 4-pole (9PH-4PO) mode and six IVPCs per phase in 3-phase 12-pole (3PH-12PO) mode are modulated with the same reference wave and phase-displaced triangular waves. This results in the generation of multilevel voltage with improved harmonic voltage profile, i.e., minimizes the torque pulsations of nine-phase PPMIM drive. The validation of the proposed MLI-fed 5 hp nine-phase PPMIM drive is carried out by using the Ansys Maxwell FEM tool as well as with an experimental prototype.

Topological Boundary Modes from Translational Deformations.

Localized states universally appear when a periodic potential is perturbed by defects or terminated at its surface. In this Letter, we theoretically and experimentally demonstrate a mechanism that generates localized states through continuous translational deformations of periodic potentials. We provide a rigorous proof of the emergence of the localized states under the deformations. The mechanism is experimentally verified in microwave photonic crystals. We also demonstrate topological phase windings of reflected waves for translated photonic crystals.

Skyrmionic chains and lattices in s+id superconductors

We report characteristic vortex configurations in $s+id$ superconductors with time reversal symmetry breaking, exposed to magnetic field. A vortex in the $s+id$ state tends to have an opposite phase winding between $s-$ and $d-$wave condensates. We find that this peculiar feature together with the competition between $s-$ and $d-$wave symmetry results in three distinct classes of vortical configurations. When either $s-$ or $d-$ condensate absolutely dominates, vortices form a conventional lattice. However, when one condensate is relatively dominant, vortices organize in chains that exhibit skyrmionic character, separating the chiral components of the $s \pm id$ order parameter into domains within and outside the chain. Such skyrmionic chains are found stable even at high magnetic field. When $s-$ and $d-$ condensates have a comparable strength, vortices split cores in two chiral components to form full-fledged skyrmions, i.e. coreless topological structures with an integer topological charge, organized in a lattice. We provide characteristic magnetic field distributions of all states, enabling their identification in e.g. scanning Hall probe and scanning SQUID experiments. These unique vortex states are relevant for high-T$_c$ cuprate and iron-based superconductors, where the relative strength of competing pairing symmetries is expected to be tuned by temperature and/or doping level, and can help distinguish $s+is$ and $s+id$ superconducting phases.

Active Phase Fault-Tolerant Control of 12-Phase Permanent Magnet Synchronous Generator Controllable Rectifier System

The multi-phase permanent magnet synchronous generator controllable rectification system has the capability of fault-tolerant operation and high reliability, and is widely used in ship power systems. After a phase loss fault occurs in such a system, the DC current output from each rectifier bridge is unbalanced, and the DC voltage ripple coefficient increases. In this paper, from the perspective of power balance distribution of residual phase windings and the symmetrical operation of the system, the design of fault-tolerant control strategy is carried out with current equalization and DC voltage maintenance as the control target. After detecting the phase loss fault of the generator, the blocking fault corresponds to the trigger pulse of the rectifier bridge connected to the whole set of three-phase windings, and the remaining three rectifier bridges are connected in parallel to provide the DC voltage to the load, and the trigger angle of the remaining three sets of rectifier bridges is adjusted to balance the output DC current of each bridge. The simulation and experimental results of a 100kW 12-phase permanent magnet synchronous generator controlled rectifier system operating under normal, phase loss and fault tolerance conditions are compared and analysed. The designed control method can effectively reduce the DC current imbalance and improve the DC power supply quality.

A Diagnosis of Stator Winding Fault Based on Empirical Mode Decomposition in PMSMs

Stator winding faults may cause severe damages in Permanent Magnet Synchronous Motors (PMSM) if not detected early on. The earliest fault detection in motors should be made during transient states throughout the initial starting period. A new approach based on Empirical Mode Decomposition (EMD) and statistical analysis was presented for detecting stator winding fault by way of transient state phase current of PMSM in this study. Models based on finite elements method were developed for the PMSM representing the healthy and faulty states in order to implement the suggested fault detection method. Afterwards, transient state stator phase winding currents were measured for healthy and faulty states under nominal load in accordance with motor models. These non-linear current signals monitored were separated into its Intrinsic Mode Functions (IMF) via the EMD method. Pearson Correlation Coefficient was used for determining the IMF that most resembles the characteristics of the main signal. Statistical parameter-based feature extractions were carried out for the IMF signals determined for the healthy and faulty states. Fault and fault level detection were carried out successfully by comparing the obtained feature vectors. The acquired results have put forth that the suggested method can be used securely for fault detection in electrical machines especially for early fault detection.

Measuring a dynamical topological order parameter in quantum walks

Quantum processes of inherent dynamical nature, such as quantum walks, defy a description in terms of an equilibrium statistical physics ensemble. Until now, identifying the general principles behind the underlying unitary quantum dynamics has remained a key challenge. Here, we show and experimentally observe that split-step quantum walks admit a characterization in terms of a dynamical topological order parameter (DTOP). This integer-quantized DTOP measures, at a given time, the winding of the geometric phase accumulated by the wavefunction during a quantum walk. We observe distinct dynamical regimes in our experimentally realized quantum walks, and each regime can be attributed to a qualitatively different temporal behavior of the DTOP. Upon identifying an equivalent many-body problem, we reveal an intriguing connection between the nonanalytic changes of the DTOP in quantum walks and the occurrence of dynamical quantum phase transitions.

Research on modeling and fault diagnosis of inter-turn short fault of permanent magnet synchronous motor

The stator winding inter-turn short fault of permanent magnet synchronous motor (PMSM) is a common motor fault with high probability. If this fault is not detected and handled in time, small initial fault will rapidly develop into other faults such as grounding short, inter-phase short, winding short et al., and even the motor damage. In order to diagnose the inter-turn short fault of PMSM, this paper firstly builds the model of the inter-turn short fault of PMSM, and then proposes a fast and simple fault diagnosis method for extracting the features of the inter-turn short fault under noise. For the first time, by introducing the full-short-circuit resistance Rf that relates with the fault severity factor δ and by estimating the inductance of inter-turn short fault motor on-line according to the three principles of the inductance calculation, which is used in the inter-turn short fault of transformer winding, the inter-turn short analysis model of PMSM is deduced. The model can be used to simulate the performance not only the health of PMSM but also the fault of inter-turn short fault of PMSM in one phase winding. This paper analyses the transient and steady state performance of 3-phase unbalanced current, speed and electromagnetic torque ripple and the relationship between full-short-circuit resistance and short current under fault condition. Finally, a fast and simple on-line fault diagnosis method of PMSM with inter-turn short fault is proposed based on phase sensitive detection (PSD) algorithm. The method uses the fundamental and third harmonic features of inter-turn short fault current. The simulation results show that the model can be well suited for the simulation of PMSM with inter-turn short fault, and the method can effectively extract the features and diagnose the fault.

Математическое описание вентильного индукторного генератора с конденсаторным возбуждением

Autonomous power plants have been given a boost by the development of electric vehicles. The presented power plant based on a switch reluctance machine with a new principle of phase winding excitation is a new technical solution. The new principle of exciting phase windings is based on the features of such electrical machines’ operation. This feature is the trapezoidal form of the phase voltages. This allows switching and excitation of phase windings in the natural mode. That is, this technical solution eliminates the need for tracking and switching phase currents depending on the position of the rotor. The winding is excited by switching capacitors of the idle phase. This can greatly simplify and reduce the cost of electronic control equipment of the switch reluctance generator. Due to the design novelty, the considered technical solution has not previously been investigated by either foreign or domestic scientists. This article provides a mathematical description of the work and developed a mathematical model of the switch reluctance generator with capacitor excitation. This mathematical model allows computing the current and EMF in the electrical machine, and in the external electric circuit, and the value of the torque. The presented results of calculations and experiments confirm the adequacy of the mathematical model. The developed model allows one to visually examine the electromagnetic processes, the performance and functioning of the system in various modes under various external influences, to develop control algorithms and evaluate the energy performance of the generator. The model can also be the basis for a technique of designing and construction of new facilities.

Design and Characteristics Investigation of Novel Dual Stator Pseudo-Pole Five-Phase Permanent Magnet Synchronous Generator for Wind Power Application

The main focus of this paper is to design and assess the characteristics investigation of Novel Dual Stator Pseudo-Pole Five Phase Permanent Magnet Synchronous Generator (NDSPPFP-PMSG) for wind power application. The proposed generator has a dual stator and two sets of five phase windings which enhance its power density and fault tolerant capability. The novelty of this generator is based on the fact that, eight magnetic poles are formed using only four poles of actual magnets on both the surfaces of the rotor. For the designing and optimal electromagnetic performance of the proposed generator, a Dynamic Magnetic Circuit Model (DMCM) is reported. To validate the results obtained from DMCM, Finite Element Method (FEM) has been opted owing to its high accuracy. For showing the performance superiority, the proposed generator is compared with two conventional generators namely, Dual Stator Embedded-Pole Five Phase (DSEPFP) and Single Stator Single Rotor Five Phase (SSSRFP) PMSG. To compare their performances, FEM results are considered. The electromagnetic performance namely, generated Electromotive Force(EMF), percentage(%) Total Harmonic Distortion(THD) of generated EMF, generated EMF vs speed, terminal voltage vs load current, electromagnetic torque developed on rotor vs time, %ripple content in the torque, and %efficiency vs load current are investigated for all the three generators. From these investigations, it is found that the power density (power to weight ratio) of the proposed generator is maximum.

Integrated on board Battery Charger Using Fuzzy Logic Controller for Plug-in Electrical Vehicles

Expanding usage of PHEV has certain considerations like high charging time, low range of driving and less number of stations for charging. PHEV chargers are known for two types as off board and on-board chargers. In this, 1-phase integrated on-board charger utilizing Fuzzy Logic based PEV 3-phase ac machine (PMSM) with its converter for traction, is proposed. The process for charging enables Power Factor Correction (PFC) in the source end. The 3-phase windings of the machine are used in the place of inductors to act as interleaved boost converter. A circuit utilizing 3-phase PMSM is built in MATLAB SIMULINK as well as verified the execution by using Fuzzy Logic Controller (FLC). An approximately unified power factor (PF) with less amount of THD of input current is obtained.

К расчету высокодинамичных электродвигателей

The use of electric drive in industrial and specialized facilities, and transport, in particular aircraft, requires the formation of transient processes of the drive a number of requirements aimed at achieving the desired level of either maximum performance or minimum level of losses, or limitation of dynamic loads in elements of kinematic diagram connecting the actuator with the actuator, or combination of these parameters. However, often increased interest is shown to highly dynamic motors with maximum angular speedup and braking. As is known, the speed of the electric motor is characterized by its electromechanical constant, which depends on the moment of inertia of the rotor, determined by its dimensions. Based on the analysis of the equations of motion of the motor defined by the ratio between the moment of inertia of the actuator and the moment of inertia for highly dynamic drive motor which delivers maximum speedup. This analysis was carried out taking into account the resonant phenomena, which limits the axial length of the rotor. The relations between the main dimensions of the high-dynamic motor providing the maximum speedup at the given load parameters are also determined. Recommendations on the choice of electromagnetic loads of such an motor are given. In particular, the ways of increasing the linear load contributing to the growth of the electromagnetic torque of the engine are considered. This is the possibility of cryogenic cooling, allowing the use of superconducting armature windings and excitation, as well as the correction of the geometry of the core, in particular the elongation of the tooth height. The latter is confirmed by numerical calculation of the electromagnetic moment of the four-pole reactive machine at different depths of the trapezoidal groove. The dependences characterizing the reduction of the active resistance of the phase winding during liquid nitrogen cooling are also given, which contributes to the increase of the linear load. Thus, the proposed design recommendations are given taking into account the possibility of developing an engine using superconducting windings.