Abdulkadir Balikci

A Novel Magnetic-Levitation System: Design, Implementation, and Nonlinear Control

This paper concerns the design, implementation, and nonlinear velocity-tracking control of a novel magnetic-levitation (maglev) system for magnetically levitated trains. The proposed system uses only one tubular linear induction motor to produce three forces required in a maglev system: propulsion, levitation, and guidance. Classical maglev systems, on the other hand, contain a separate force-generating system to build each of these three forces. Another benefit that the proposed system offers is that there is no need to control the guidance, and particularly, the levitation forces, one of the most challenging tasks in maglev systems. The system always centers the moving part during operation and eliminates the necessity for control of the levitation and guidance forces. However, the propulsion force strongly requires some control efforts because a linear induction motor has nonlinear system dynamics. This paper gives a condensed design guideline based on the mature theory of electromagnetic launchers, particularly the linear induction launcher type. It explains the implementation process, shows experimental test results, and finally, presents a nonlinear partial state-feedback controller for the proposed system.

On the Design of Coilguns for Super-Velocity Launchers

This paper deals with the design of a super-velocity launcher with muzzle velocity up to 8 km/s. It addresses the design specifications of the linear induction section of the launcher having a 4-km/s breech velocity, and utilizing a projectile weighing 1 kg. The overall launcher is a hybrid design, using a gas gun to obtain the initial 4-km/s speed at the input to the coil launcher. The design sequence starts with the maximum temperature allowed by the sleeve material; continues by selecting the required number of sections in the barrel; the dimensions of the drive coils are determined; and our existing computer code is used to optimize the transition between the gas gun and the first section of the coil gun, and between successive sections of the barrel. The code utilizes our latest design scheme; that is, the drive coils are connected in parallel; one flywheel generator per pole is used; and all of the generators in a given section are shaft-coupled, so that they all rotate at the same speed. The design specifications are presented in this paper together with simulation results for the phase voltages, the currents, and the acceleration forces

Improved performance of linear induction launchers

This paper deals with the effect of parallel (rather than series) connection of the drive coils on the input voltage requirements, as well as on the energy utilization, of hypervelocity linear induction coil launchers fed by flywheel motor/generator sets. All of our previously published studies, 1987 to date, have dealt with series (rather than parallel) connected drive coils, which led to high input phase voltages and relatively low phase currents. In practice, the phase voltage per coil length should be kept below 30 kV/cm, the breakdown voltage of air. Furthermore, at any given time during the acceleration, the moving projectile (surrounded by a cylindrical sleeve) occupies only a portion of a barrel section length. When a parallel connection is used, the currents in the drive coils around the sleeve will be higher than the currents in the other coils in that section. That results in a greater accelerating force than in the series case, which leads to improved energy utilization. The simulation code used in our previously published work to predict the performance of a sectionalized, 3 kg projectile machine, was modified to obtain parallel-connection results for a similar machine. The paper describes the new drive-coil/pulse-generator configuration, explains the mathematical model, and provides graphs to compare the new results with those obtained previously with the series configuration.

Flywheel motor/generator set as an energy source for coil launchers

This paper deals with the design of a flywheel motor/generator set as an energy source for an eight-section hypervelocity linear induction coil launcher. The paper presents a conceptual design of the flywheel motor-generator set which use a structure that was chosen from the literature. A previously developed simulation program was modified to include the generator equivalent circuit and its flywheel inertia. A few simulation results are also included in the paper to demonstrate the applicability of the concept.

Concerning the Design of a Novel Electromagnetic Launcher for Earth-to-Orbit Micro- and Nanosatellite Systems

This paper presents an alternative launcher design for Earth-to-orbit (ETO) micro- and nanosatellite systems. The main goal of the design is to reduce the cost of the launching operation. This paper also addresses the calculation of the energy required for the launching operation and the selection of a power source for the designed satellite launcher. The method introduced here proposes a vertical-takeoff electromagnetic launcher for ETO micro- and nanosatellite systems. The design specifications are 7-km/s muzzle velocity and 30000-gee acceleration for a 10-kg payload. It is expected that the proposed design would present a viable alternative to conventional launchers for ETO systems.

Experimental Performance Investigation of a Novel Magnetic Levitation System

This paper deals with the design, construction, and especially the testing of a new magnetic levitation (maglev) train driven by an air-cored tubular linear induction motor. The proposed new design topology uses only one force-generating system (motor) to produce the three forces required in a maglev system: propulsion, levitation, and guidance, whereas classical maglev trains use separate motors or permanent magnets to produce each of these forces. Moreover, the system eliminates the need for control of the levitation and guidance forces. This paper presents a condensed design guideline, simply explains the implementation process of a laboratory-scale prototype, shows in detail the experimental test results—including the low-damping problem—and then addresses the advantages of the proposed system over existing maglev systems.

Numerical Investigation of the Effect of a Longitudinally Layered Armature on Coilgun Performance

The effect of a longitudinally layered armature on coilgun performance is investigated by using a 2-D axially symmetric cylindrical quasi-static finite-difference time domain method. The singularity extraction and Mur-type absorbing boundary condition are adopted with the numerical solution. The results obtained show that the best coilgun performance in the sense of the induced propulsive armature force is observed when the conductivity of the outer layer of the armature is smaller than that of the inner layer. This phenomenon can be explained in terms of impedance matching based on skin depth evaluation.

A novel Lithium-Ion-Polymer battery model for hybrid/electric vehicles

Lithium-ion polymer batteries are getting popular in both renewable energy systems and electric vehicles thanks to their high power and energy density. Therefore, accurate battery models are vital in design and simulation of hybrid/electric vehicle propulsion systems. In this work a novel equivalent circuit-mathematical battery model whose parameters were extracted from experimental data is proposed. The simulation results were compared with actual results obtained from a series of experiments carried out using an automotive-grade 11 Ah Kokam SLBP lithium-ion polymer battery. The model exhibits consistent behaviour.

An analytical battery state of health estimation method

Decrease in state of health (SoH) of a battery is a measure of end of battery life. Also available battery capacity is dependent on battery life either. Thus accurate estimation of SoH and cycle number of a battery are very important. In this study a method was proposed in order to estimate battery cycle number using ECE 15 driving cycle. Also another method to obtain SoH of a battery using the cycle number is introduced. The results of both methods are compared with the outputs of an experimental setup.

3-D FEM Analysis of a Novel Magnetic Levitation System

This paper deals with the 3-D finite element method (FEM) analysis of a novel magnetic levitation (maglev) train driven by an air-cored tubular linear induction motor. This new maglev system originates from electromagnetic launcher (EML) technology, especially linear induction launcher (LIL) type. Some 2-D magnetic analyses based on current sheet model or transmission line approach for the LIL type launchers are available in the literature, but this paper provides an alternative way to analyze LIL type of EMLs using 3-D FEM. The analysis examines the variation of propulsion, levitation, and guidance forces induced in the moving part. It is expected that the possible results of this magnetic analysis will lead to some new and important design considerations for the novel maglev system.