Saturation Of Magnetic Circuit Research Articles

УНІВЕРСАЛЬНА МАТЕМАТИЧНА МОДЕЛЬ АВТОНОМНОГО АСИНХРОННОГО ГЕНЕРАТОРА З КОНДЕНСАТОРНИМ САМОЗБУДЖЕННЯМ

A universal mathematical model of an autonomous asynchronous generator with capacitor self-excitation in retarded phase coordinates is proposed, taking into account the electromagnetic connections between the windings of the stator and rotor phases, saturation of the main magnetic circuit, and active power losses in the magnetic circuit elements. The model provides an opportunity to analyze stable periodic modes and transient electromagnetic and electromechanical processes in autonomous power supply systems with arbitrary switching schemes of its elements and asynchronous generators. The model provides the possibility of taking into account the residual magnetization of the magnetic circuit of an asynchronous generator and the change in rotor speed during the course of the self-excitation process of an asynchronous generator with a grounded neutral of the stator winding and an asymmetric load. References 10, figures 2.

Modelling and optimization of TPMLMs with slotted stators based on Bayesian DNN

AbstractThe Permanent Magnet Linear Motor (TPMLM) is widely used in different industrial fields. TPMLMs with slots and iron cores have high power density, but their thrust fluctuations and copper losses are significant. Due to the nonlinearity and saturation of magnetic circuits, their electromagnetic models are complex and the accuracy of numerical methods is very inferior. Substantially accurate modelling is crucial for motor optimisation design. In this paper, a data‐driven modelling method based on Bayesian optimisation deep neural network (DNN) is proposed to improve the accuracy of the electromagnetic field. The finite element (FE) modelling under different structural parameters is analysed and provides a training dataset for DNN. Then, a multi‐objective optimisation problem for the slotted TPMLM is carried out based on the multi‐objective black hole algorithm. Compared to the original design, the average thrust of TPMLM increased by 49.37%, the thrust fluctuation percentage decreased by 9.59%, and the coil copper consumption percentage decreased by 2.64%. The results show that the improved DNN model has very high modelling accuracy, providing a new way for motor design and optimisation.

Определение факта насыщения магнитопровода трансформатора тока на основе непрерывного измерения сопротивления цепи намагничивания

Saturation of electromagnetic current transformers in transient modes of operation of an electric power system can lead to incorrect operation of relay protection devices. One of the most promising directions to improve the stability of the operation of relay protection devices in such modes is digital correction of secondary current. Currently, effective methods have been developed to restore the secondary current based on determination of magnetic circuit saturation. However, the practical application of these methods is impossible due to the imperfection of existing methods of secondary current segmentation. Thus, it is urgent to develop a method to determine saturation for implementation of digital correction algorithms for electromagnetic current transformers. To solve the stated problem, methods of mathematical modeling of electrical circuits containing transformers and the small-disturbance theory have been used. Verification of the research results is carried out in the Matlab software package. A mathematical criterion is formulated to determine the saturation of the magnetic circuit of an electromagnetic current transformer based on the inductance of the magnetization circuit. A method of segmentation of the secondary current has been developed for the implementation of digital correction algorithms based on the proposed criterion. The effectiveness of the developed method to determine the saturation of the magnetic circuit of an electromagnetic current transformer using computational experiments in the Matlab software package is demonstrated. It is planned to verify the developed method using a physical model of an electromagnetic current transformer.

Study and Implementation of a Computational Platform to Drive a Switched Reluctance Motor 8x6 for Electric Vehicles Applications

This paper aims to develop a computational platform for study and analysis of a Switched Reluctance Machine (SRM) 8x6 operating as motor for electric vehicles applications. In SRM modelling it was used the non-linear approach, which includes the representation of the magnetic circuit saturation through the concept of incremental inductance. For machine drive is used the topology of the asymmetrical half-bridge converter. The proposal is to make the computational representation to simulate of the behaviour of this machine under several operations conditions, guaranteeing safety and reliability of the results. Besides the drive of the SRM, the computational platform allows the study of the various magnitudes and aspects of this machine, such as: inductance, torque, speed profile, power and efficiency. A current control is also implemented, and simulation results are presented and discussed.

An improved equivalent magnetic network model of IPM motor in electric vehicles for dynamic simulation of transient effects

The existing electric motor model for electric vehicles cannot address the simulation of transient conditions. Moreover, it is difficult to balance the computation time and simulation accuracy. To address these shortcomings, an improved internal permanent magnet motor model containing nonlinear magnetic field factors was proposed based on the equivalent magnetic circuit theory. The effects of the magnetic circuit saturation, cogging torque, and magnetic field harmonics on the electromagnetic torque could be reflected. Furthermore, the electromagnetic vibration and rotor eccentricity could be considered. To improve the computational efficiency of the equivalent magnetic network method, lumped parameter or mesh-based methods were used for flux paths with different complexities. Second, the single-layer mesh-based method with local variable permeability parameters improved the efficiency of the air-gap dynamic analysis and computational efficiency while simulating 2D flux paths. The radial and tangential electromagnetic forces were calculated using the Maxwell tensor method and the action on the rotor. The accuracy of the nonlinear magnetic field modeling was verified by finite element analysis and experimental. In addition, the motion modeling method and dynamic characteristics of the model were studied. A reference was provided for dynamic simulations of electric vehicles and other using permanent magnet motors.

The Phasor Diagram of a Superconducting Synchronous Electrical Machine

This paper describes a universal method proposed by the author for the evaluative analytical calculation of the main parameters of synchronous electrical machines, including superconducting ones. Traditional methods for analytical calculation of parameters to build a phasor diagram of electrical machines require a calculation of all dimensions of the active zone, tooth-slot zone and frontal parts of armature windings. All sizes and local states of magnetic circuit saturation are necessary for the calculation of magnetic conductivities. Traditional analytical methods use, among other things, empirical formulas and non-physical coefficients and allow one to calculate only standard machines with classic tooth-slot zones and armature winding types. As a result of drawing a phasor diagram using traditional methods, the angle between the electromotive force and voltage is calculated, which is the machine’s internal parameter and has no major significance for users. The application of modern computer programs for simulation requires a preliminary analytical calculation in order to obtain all dimensions of the three-dimensional model. FEM simulation programs are expensive, require expensive high-performance computers and highly paid skilled personnel. Fast analytical techniques are also required to assess the correctness of the obtained automatic computer simulation results. The proposed analytical method makes it possible to quickly obtain all the main parameters of a newly designed machine (including superconducting ones and those of non-traditional design) without a detailed calculation of the dimensions of the tooth-slot zone and armature end-windings. The characteristic values of load angles are set according to the results of simple calculations, and the desired values, obtained via plotting, represent the inductive resistances of armature winding and inductive voltage drop across it. Results of practical significance, calculated from the voltage diagram, are as follows: the inductor’s magnetomotive force necessary to maintain the nominal load voltage value, regardless of the magnitude (including double overload) and type of the connected load, or the main dimensions of the active zone.

Mechanism model of suspension force for spherical bearingless flywheel machine

The flywheel energy storage system (FESS) has drawn more and more attentions in the past decades, and its operation performance is greatly dependent on the suspension characteristics of the flywheel machines. This paper proposed a new mechanism model of the suspension force for the spherical bearingless flywheel machine (S-BFM), which may be applied for the machine optimal design, performance analysis or efficiency evaluation. In the proposed model. the magnetic field partition method was used to solve the permeability of the machine in different diffused flux regions. The inherent characteristics of the rotor eccentricity and magnetic circuit saturation are considered by combining maxwell tensor method and equivalent magnetic circuit method. By considering the rotor eccentricity, magnetic circuit saturation and diffusion flux, the proposed model processes higher precision over the traditional model, and its outputs are quite close to that of the finite element analysis (FEA).

Analysis of Skewing Effects on Radial Force for Different Topologies of Switched Reluctance Machines: 6/4 SRM, 8/6 SRM, and 12/8 SRM

Reducing vibration and noise in electrical machines for a given application is not an easy task, especially when the application imposes some restrictions. There are many techniques for reducing vibration based on design or on control. Switched reluctance motors (SRMs) have a double-saliency structure, which results in a radial pulsation force. Consequently, they cause vibration and acoustic noise. This paper investigates the correlation between the radial force and the skew angle of the stator and/or rotor circuits. The analysis is computed from two-dimensional (2D) transient magnetic finite-element analysis (FEA) of three machine topologies, namely the 12/8 three-phase SRM, the 6/4 three-phase SRM and the 8/6 four-phase SRM. Compared to SRM, these topologies have the same basic dimensions (stator outer diameter, rotor outer diameter, and length) and operate in the same magnetic circuit saturation. The flux linkage and torque characteristics of the different motors are presented. The radial force distributed on the stator yoke under various skewing angles is studied extensively by FEA for the three machines. It is also demonstrated the effect of skewing angles in the reduction of radial force without any reduction in torque production.

A General Decentralized Dynamic State Estimation With Synchronous Generator Magnetic Saturation

The saturation of the nonlinear magnetic circuit of synchronous generators is often neglected when performing Kalman filter-based dynamic state estimation (DSE), yielding significant estimation bias. This letter addresses this problem and proposes a generalized DSE framework to handle magnetic saturation. Moreover, this letter derives a state initialization procedure that improves the Kalman filter tracking speed. The framework is flexible in dealing with different saturation functions and generator models. Numerical results on the Texas 2000-bus system verify the effectiveness of the proposed method.

Instantaneous Torque Modeling and Torque Ripple Reduction Strategy for Flux Modulated Doubly-Salient Reluctance Motor Drives

In this article, a novel instantaneous electromagnetic torque modeling technique and current component distribution strategy are proposed for torque ripple reduction in three-phase flux modulated doubly-salient reluctance motor (FMDRM) drives. First, the analytical model of the instantaneous electromagnetic torque of a three-phase FMDRM is established, where the contributions of current components and harmonic inductance components are considered. The generation mechanisms of the average torque and torque ripple components are investigated in detail. Furthermore, based on the analytical instantaneous electromagnetic torque model, a simplified current component distribution strategy is proposed to further reduce the torque ripple of the FMDRM. Taking the torque ripple minimization as the optimization objective, the current advanced angle is optimized and the corresponding current component distribution strategy is carried out to reduce the torque ripple. The magnetic circuit saturation effect is also taken into account. Compared to the conventional scheme, the control freedom degree of the three-dimensional current controller in the FMDRM drive is fully utilized and the torque ripple of the FMDRM can be significantly reduced without the sacrifice of output torque capability and system efficiency. Experimental results are carried out on a three-phase 12/8 FMDRM prototype to verify the effectiveness of the proposed control strategy.

A Novel Mesh‐Based Equivalent Magnetic Network for Deep Saturation Region of Permanent Magnet Machine

AbstractPartial deep saturation of magnetic circuit is common in short‐term working permanent magnet (PM) machines in aviation, aerospace, new energy power generation and other fields. In order to accurately calculate the electromagnetic characteristics of the short‐term working machine, a novel mesh‐based equivalent magnetic network for the deep saturation region is proposed. Firstly, the deep saturation mechanism of the magnetic circuit of short‐term working motor is analyzed, and the deep saturation region is determined; Secondly, a Pointy topped hexagonal segmentation approach (PT‐HSA) grid generation method is proposed to effectively simulate complex magnetic flux paths. The PT‐HSA grid division and node compilation rules were analyzed in detail. In addition, a nonlinear magnetic network model based on reluctance grid model and equivalent magnetic circuit model is established. Compared with the quadrilateral segmentation approach (QSA) model, the calculation results of PT‐HSA model are closer to the finite element simulation results in the loading and instantaneous compensation conditions. Finally, an experimental platform is built, and the accuracy of the PT‐HSA magnetic network model is verified by the experimental results. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Устройство мягкого пуска для системы электродвижения

Object and purpose of research. Soft start devices (SSD) are designed for autonomous electric power systems to prevent in-rush currents caused by saturation of magnetic circuit of power transformers and frequency converters capacitors charge. Materials and methods. A graphical description of the process is given, accompanied by in-rush currents upon switch-on, and a circuit design, on the basis of which a soft start is carried out for transformers of the main switchgear (MSG). Main results. Schematic diagrams and design documentation of the SSD have been developed, the internal view of the device in as-delivered configuration is given. Conclusion. The SSD device has passed acceptance tests and is ready for delivery for further operation.

Research on Speed Regulation performance of switched reluctance Motor based on nonlinear active disturbance rejection

Abstract The state has vigorously advocated new energy electric vehicles in recent years. Compared with other motors, switched reluctance motor has the advantages of superior speed regulation performance, low production cost and strong controllability. However, due to its double salient structure, it is easy to produce magnetic circuit saturation, and its control is non-linear, which is easy to lead to large torque ripple and strong noise. To solve this problem, a control strategy combining active disturbance rejection control and direct torque is proposed to suppress torque ripple. A simulation model is built and calculated with simulation software. At the same time, it is compared with PI control and fuzzy PID control under direct torque control. Finally, the simulation experiment is carried out on a 6 / 4 motor. The simulation results also show that the direct torque control strategy based on active disturbance rejection control technology can effectively control the torque and speed of switched reluctance motor.

Optimal Design of Machine Tool Vibration Reduction Based on Magneto-rheological Damper

This paper takes the three - way redundant drive parallel machine tool as research object, designs a magneto-rheological damper with displacement amplification function and simulates the magnetic circuit saturation of the damper by the Ansys workbench finite element analysis software, so that the output of the damper comes to optimization. The research results show that the magnetic field distribution is more reasonable, and the mechanical properties of the damper are improved. The optimization method is feasible and effective.

SRM simulation with reduced amount of initial information taking into account saturation of magnetic circuit

The article describes the currently used approaches to mathematical modeling of switched reluctance electric machines. It is shown that the traditional approach uses a large amount of initial information on the dependence of the flux on the current and the angular position of the rotor in the form of lookup tables. It is proposed to use the description of the flux using the hyperbolic arcsine function. This approach will reduce the amount of preliminary information and thus simplify the procedures for configuring control systems.

Sensorless Control of Asynchronous Motor at Low speed

The subject of the submitted paper is to provide a detailed description of simulation control of rotor position sensing of an asynchronous motor by an injection method of high-frequency analogue signal on supply signal frequency of up to 5 Hz, i.e., at zero and low speed. In general, contrary to discrete signal injection, the implementation of the method appears to be simpler for continual signal injection aimed at monitoring of asymmetry of rotary electric machines, however, the process of information gathering related to position of monitored asymmetries during signal reaction processing is more complicated. Genuine verification of the method requires designing a mathematical model of a motor including asymmetries caused by rotor grooving and by magnetic core saturation. The asymmetries occurring in asynchronous motors considerably influence the instant value of a stator induction LS. Asymmetries caused by magnetic circuit saturation were identified and eliminated because of inducing the measured signal distortion. The elimination method LMDEM is the method proposed for repressing the asymmetries. The asymmetries caused by rotor grooving are intended to detect the rotor position. In final part, mathematical functions will be used for converting the signal to rotor position.

Design and Optimization of Hybrid-Excited Claw-Pole Machine for Vehicle

In order to overcome the shortcomings of traditional electric excitation claw machine such as large leakage of magnetic field and easy saturation of ferromagnetic materials, a new topology structure with permanent magnet and electrical excited of shunt excitation scheme is proposed for claw-pole machine. Firstly, the output characteristics of voltage and current in power generation and electric state for claw-pole machine are analyzed by 3-D finite element method (FEM). And the influence of different excitation currents on the saturation state of magnetic circuit is calculated. On this basis, the influence of saturation of magnetic circuit is considered for electromagnetic torque and torque ripple. Therefore, under the condition of unsaturated flux density, in order to ensure the fastest and most stable start of the vehicle, it is necessary to obtain the maximum excitation current. Finally, a hybrid-excited claw-pole machine with rated power of 1.5kW is manufactured, and the on-load and no-load characteristics of prototype are tested to verify the feasibility of the hybrid-excited topology proposed.

Finite Element Modeling of Shunt Reactors Used in High Voltage Power Systems

Shunt reactors are important components for high-voltage and extra high voltage transmission systems with large line lengths. They are used to absorb excess reactive power generated by capacitive power on the lines when no-load or under-load occurs. In addition, they play an important role in balancing the reactive power on the system, avoiding overvoltage at the end of the lines, and maintaining voltage stability at the specified level. In this paper, an analytical method based on the theory of magnetic circuit model is used to compute the electromagnetic fields of shunt reactors and then a finite element method is applied to simulate magnetic field distributions, joule power losses, and copper losses in the magnetic circuit. In order to reduce magnetic flux and avoid magnetic circuit saturation, it is necessary to increase the reluctance of the magnetic circuit by adding air gaps in the iron core. The air gaps are arranged along the iron core to decrease the influence of flux fringing around the air gap on shunt reactors' total loss. Non-magnetic materials are often used at the air gaps to separate the iron cores. The ANSYS Electronics Desktop V19.R1 is used as a computation and simulation tool in this paper.

Universal mathematical model of asynchronous machine as an element microgrid in smart grid

An universal mathematical model of an induction machine (IM) has been constructed, taking into account the saturation of the main magnetic circuit of its magnetic core and the active power losses. The proposed approach to IM modeling expands the abilities of MATLAB / Simulink environment for analysis of the electric power supply systems (microgrid in the smart grid) with the nonlinear elements and dynamic load in abnormal, asymmetric and fault regimes.

Uticaj programirane promene faznog stava struje na specifičnu silu cilindričnih linearnih motora sa stalnim magnetima

Due to their prominent properties, tubular permanent magnet linear motors are increasingly being employed in areas in which hydraulic and pneumatic actuators are traditionally used. In order to achieve the highest possible specific force, a method based on a programmed change of the phase angle is proposed. The proposed method takes the influence of the magnetic circuit saturation on the electromagnetic interaction and current form. Simulation results are obtained using the finite element method. This method of determining the phase angle can be applied to all machines with permanent magnets in which the saturation of the magnetic circuit is pronounced.