Armature Parameters Research Articles

Design and Analysis of a Novel Hybrid Excitation Flux Reversal Machine

A novel hybrid excitation flux reversal machine (HEFRM) is developed. The machine has a simple reluctance rotor and a stator, which has both an ac armature winding and a dc field winding. The core on the surface of the pole arc at the centerline of the stator pole and the core on the outer surface of the stator yoke each have a slot along the rotating axis, where the field windings are placed. A permanent magnet (PM) with opposite polarity is placed respectively on each side of a slot in the same stator pole. In this paper, the working principle of the new HEFRM is introduced, the influence of magnetic pole parameters and armature parameters on motor performance are also analyzed, and genetic algorithm (GA) is used for multi-objective optimization of the torque characteristics. Finally, the HEFRM prototype is built, and its theoretical correctness is verified by the finite element analysis (FEA).

An initial velocity model study of electromagnetic railgun based on back propagation neural network

The velocity of launch has been the key factor restricting the application of electromagnetic rail. For electromagnetic launch system, the structural parameters change directly or indirectly affect the Launching velocity of the electromagnetic launch system. In order to improve the initial velocity of the electromagnetic railgun. The mathematical model of electromagnetic rail gun launch was set up, the structure parameters of armature and the size of the pretension force between armature and orbital were variables, based on the target function, The equivalent model of rail gun BP neural network is established by using the calculation results of mathematical model, and the model of rail gun BP neural network was optimized by electromagnetic emission test data. The error of rail gun BP neural network model optimized by experimental data is 18.5% lower than that before optimization and 6.5% lower than that of experimental data. The results show that the launch speed of the optimized rail gun BP neural network model is closer to the actual speed.

Vibration Characteristics of Thomson Coil Actuator Based on Simulation and Experiments

To meet the fast and stable operational demands of DC circuit breakers (DCCBs), an ultrafast mechanical switch (UFMS) based on a Thomson coil (TC) actuator is studied. First, a 2D finite element (FE) transient axisymmetric model of a TC actuator coupled with magnetic fields, solid mechanics and electrical circuit modules is implemented. A time-domain analysis shows that the armature bending may limit the electromagnetic coupling effects between the coil and armature at the initial stage of driving, and this motion is accompanied by the fluctuation of the displacement and stress of each part. A frequency-domain analysis shows that the dynamic response form and vibration frequency of the actuator under the action of repulsive force are consistent with those of the 4th mode, where the maximum relative displacement occurs at the armature edge. Based on this research, a new armature structure is proposed, and the relationships among armature parameters, motion characteristics, and stress distribution are studied. Finally, a 110 kV UFMS is developed, and two armatures with different parameters are built and tested to verify the accuracy of the simulation model and the effectiveness of the optimization method.

INFLUENCE OF ARMATURE PARAMETERS OF A LINEAR PULSE ELECTROMECHANICAL CONVERTER ON ITS EFFICIENCY

Purpose. The evaluation of the effect of armature parameters on the efficiency of a linear pulsed electromechanical converter, taking into account the power, speed, constructive and environmental parameters. Methodology. First, the height of the electrically conductive, coil and ferromagnetic armature of a linear pulse electromechanical converter is determined, at which the highest velocity develops. An integral efficiency index is introduced, which takes into account, in a relative way, the power, speed, energy, electrical and field characteristics of the converter. Variants of the efficiency evaluation strategy are used that take into account the priority of each indicator of a linear pulse electromechanical converter using the appropriate weighting factor in the integral efficiency index. Results. A mathematical model of a linear pulsed electromechanical converter is developed. It is established that as the height of the electroconductive, coil and ferromagnetic armature increases, the force pulse increases. The greatest speed develops with the use of a coil armature, and the smallest with an electroconductive armature. In the converter with coil and ferromagnetic armature, practically the same values of the electrodynamic and electromagnetic force pulse are realized, while in the converter the electrodynamic force is 1.52 times smaller in the converter by the electrically conductive armature. It is established that with all efficiency evaluation strategies, the converter with a coil armature is the most effective, even in spite of its constructive complexity, and the converter with a ferromagnetic armature is the least effective, although it is constructively the simplest. Originality. For the first time, using the integral efficiency index, which takes into account the power, speed, energy, electrical and field indices in a relative way, it is established that with all efficiency evaluation strategies, the converter with a coil armature is the most effective, and the converter with a ferromagnetic anchor is the least effective. Practical value. The height of the electrically conductive, coil and ferromagnetic armature of a linear pulse electromechanical converter is determined, at which the highest speed develops. It is shown that when using an electrically conductive armature, the value of the electrodynamic force pulse is lower than when using a coil and ferromagnetic armature. It is established that the converter with a coil armature is the most efficient, and the converter with a ferromagnetic armature is the least effective.

Investigation of Armature Capture Effect on Synchronous Induction Coilgun

To obtain high velocity and high energy conversion efficiency on a synchronous induction coilgun, the armature capture effect which is the inherent characteristic for the synchronous induction coilgun needs to be analyzed. The reason for the armature capture effect is first deduced and analyzed using the lumped element circuit model and then quantificational result is obtained based on the field-circuit coupled model. According to the analytical result, the method to minimize the armature capture effect is proposed from the viewpoint of the magnetic coupling between the driving coil and the armature. Several ways are analyzed through the finite-element simulation. The simulation results show that adjusting the power parameters, such as increasing the capacitance or initial voltage, and decreasing the crowbar resistance, and adjusting the armature parameters, such as decreasing the mass or adopting the solenoid armature, can minimize the armature capture effect and increase the conversion efficiency. These methods are validated through a four-stage induction coilgun. We compare the simulation results with the experimental results and show that by adjusting the armature parameters, we can minimize the armature capture effect. It provides valuable reference for synchronous induction coilgun design.

The Research on the Launching Consistence of Small Caliber Electromagnetic Railgun

Electromagnetic railgun can perform precision strike in long range. It is obtained that the scatter of velocity must be exist because there are many effectors influencing launching process, for example, the manufacturing error, the initial value of launching parameters and uncertainty during launching process and so on. Among these factors, the parameters of armature are easy to adjust to ensure the consistence of velocity. So we attempt to apply Grey Analyzing Model to carry on the study, and then by means of the measurement of strain on the barrel to verify the model. The result shows that the reasonable matching of armature mass and diameter can be helpful to improve the consistence of armature muzzle with the other parameters the same. This method is a new attempt to study the stability and consistence of velocity of solid armature.

Fault-Tolerant Permanent Magnet Synchronous Linear Motor

The principle and characteristics of Fault-tolerant Permanent Magnet Synchronous Linear Motor are introduced. The design or computational method of the polar distance of concentrated winding coil, the armature parameters, the armature winding parameters, the coil diameter, the distance from the adjacent armature windings are given. The magnetic thrust equation is derived, and the core issues are analyzed. It provided theoretical basis for structural optimization of the Fault-tolerant Permanent Magnet Synchronous Linear Motor.

Design and modeling considerations for experimental railgun armatures

A calculational method for obtaining detailed armature parameters associated with railgun launchers has been developed. Calculated parameters are obtained for device features and operating conditions supplied as input parameters. The model was validated by reproducing several sets of experimental data from a variety of devices. Model parameters associated with armature mass loss and plasma axial profiles were obtained as part of anchoring the calculations. The data included complete sets of dynamics, armature lengths, and muzzle voltages for each case studied. From the calculations, several differences between the various types of armatures (i.e. solid, hybrid, and plasma) and bore sizes were identified and found to account for the resulting performance features.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Velocity skin effect with plasma armature

The velocity skin effect is analyzed for a plasma armature railgun system. The effect is shown to produce a nearly uniform current density distribution. The governing equation is derived and solved numerically for the case in which plasma armature parameters vary only in the axial direction. This result is used to compute the temporal signature to be expected of axial B probes. Comparison with experimental data indicates that some mechanism other than the velocity skin effect is responsible for determining the current density distribution in a plasma armature. It is concluded that a likely process for explaining the observed results is the transport of magnetic flux by plasma flow, the flow being induced by viscous drag occurring at the rail/insulator surfaces.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>