Ship Propulsion Motor Research Articles

대형회전기기응용을 위한 GdBCO 레이스트랙형 팬케이크 코일의 ��치 발생과 전파특성에 관한 연구

The stability issue of high temperature superconducting (HTS) racetrack coils is one of the most important factors for the development of large-scale rotating machines, such as ship propulsion motors and power generators. However, The stability and normal zone propagation characteristics of HTS racetrack pancake (RP) coils are not sufficient yet. In this study, quench tests for a GdBCO racetrack pancake coil were carried out under the condition of <TEX>$LN_2$</TEX> at 77 K. Minimum quench energy and two-dimensional normal zone propagation velocities of the coil are also discussed. Normal zone propagation velocity in the coil's curved section is faster than in its straight section due to stress effects. The test results show that the protection of the straight section is of greater importance than that of the curved section when GdBCO racetrack pancake coils are applied to large-scale rotating machines.

Critical Current and Electric Loss Under Magnetic Field at 30 K on Bi-2223 Superconducting Coil for Ship Propulsion Motor

We are currently under development of a 1 MW-class HTS ship propulsion motor, for which rotating HTS coil made of Bi-2223 tape wire has already been successfully cooled down to 30 K and attained the target performance. There, the electric loss estimation in the HTS tape wire is required under practical operation conditions. The magnetic field angle dependency on IC-B characteristics of Bi-2223 used for the field winding was measured at 40 K. Furthermore, the interlinkage flux density on HTS coils in the horizontal and vertical directions were calculated using three-dimensional magnetic field simulations. It was found that the estimated electric loss of the entire HTS coil using these measured and simulated results was about 9 W at the operating field current of 200 A, which was considerably small compared with 30 W at 215 A, and that the operating field current of 200 A was appropriate and desirable considering the required refrigerator capacity.

US Navy's Superconductivity Programs Scientific Curiosity to Fleet Utility

The US Navy's interest in superconductivity began shortly after World War II when programs at the Naval Research Laboratory (NRL) and the Office of Naval Research (ONR) began exploring the science of superconducting materials. Throughout the 1950's and 1960's these programs discovered new superconducting materials and added much to the basic understanding of the phenomenon. Technology development programs began in the late 1960's with major efforts at ONR, NRL, and the Navy's Warfare Centers. Development of superconducting quantum interference devices (SQUIDs) used to detect underwater mines and submarines began at the Warfare Center in Panama City, FL in 1969. At the same time scientists and engineers at the Warfare Center in Annapolis, MD began their own technology efforts to develop quiet, high power density ship propulsion motors. ONR and NRL expanded their programs to include superconducting electronics as well as efforts to develop technologically useful materials (films and wires) for the Navy's technology programs. The Navy's superconductivity efforts accelerated rapidly after the discovery of high temperature superconducting (HTS) materials. A major effort led by NRL developed and launched HTS electronic devices and subsystems into space. The Navy Warfare Center in San Diego and ONR/NRL began programs developing low loss filters for electronic communications as well as the development of fast, low power superconducting digital devices. Navy scientists led industrial programs for development of full scale HTS ship propulsion motors and HTS filters for communication systems. As the 21st century began, the Navy started to develop superconducting systems for fleet implementation. The first ship to use a superconducting system was the USS Higgins that used superconducting cables in a degaussing system (2008).

ビスマス系超伝導線材と応用開発の最前線

Bismuth based high temperature superconductor has discovered by Dr. Maeda at NIMS (National Institute for Materials Science). Just after the discovery of this material, Sumitomo Electric has carried out the R&D on long length and high performance wire, and many application prototypes for more than 20 years. As a wire manufacturing technology, CT-OP (controlled over pressure sintering) process is very effective to make high performance wire. Power cable and ship propulsion motor applications using bismuth based superconducting wire are highly expected.

Superconductors to boost wind power

More powerful generators are key to growing offshore wind farms.

Quench and recovery characteristics of a racetrack double pancake coil wound withYBCO-coated conductor

The reliability of high temperature superconducting (HTS) racetrack coils is one of themost important factors for the development of large-scale rotating machines. However, it isnecessary to investigate the stability and normal zone propagation characteristics ofracetrack coils for large-scale applications such as ship propulsion motors and powergenerators. In this study, the quench/recovery characteristics of a racetrack-type, doublepancake (DP) coil, which could be applied to HTS rotating machines, were investigatedusing the voltage and temperature profiles in a cryogenic conduction cooling system. Theminimum quench heating flux and quench propagation velocity of the racetrack DP coil arealso discussed.

Basic concepts, status, opportunities, and challenges of electrical machines utilizing high-temperature superconducting (HTS) windings

An overview of the different approaches towards achieving a marketable application of a superconducting electrical machine, either as synchronous motor or generator, will be given. This field ranges from relatively small industrial drives to utility generators with large power ratings, from the low speed and high torque of wind power generators and ship propulsion motors, to high speed generators attached to turbines. Essentially HTS machine technology offers several advantages such as compactness (weight and volume reduction), increased efficiency, and other operational benefits. The machine features have to be optimized with regard to the specific application, and different concepts were developed by internationally competing teams, with Siemens being one of them. The achieved status in these fields will be summarized, pointing to the specific technical challenges to overcome. For this purpose we have not only to consider the technology of manufacturing the HTS rotor winding itself, but also to check requirements and availability of supporting technologies. This ranges from new challenges posed to the non-superconducting ("conventional") components of such innovative HTS machines, manufacturing superconducting material in the coming transition from 1st to 2nd generation HTS tape, cryogenic technology including material behavior, to new and challenging tasks in simulating and predicting the performance of such machines by computational tools. The question of market opportunities for this technology obviously is a function of all these aspects; however, a strong tendency for the near future is seen in the area of high-torque ship propulsion.

Hardware-in-the-Loop Investigation of Rotor Heating in a 5 MW HTS Propulsion Motor

Of particular concern to designers of HTS machines are potential heating effects in the superconducting windings due to AC losses caused by load fluctuations encountered in real-life operating conditions. A 5 MW HTS synchronous prototype ship propulsion motor has been tested extensively under steady-state and dynamic load conditions in the advanced test facility of the Center for Advanced Power Systems at Florida State University. This paper presents results from two tests of rotor heating effects, one employing single frequency torque oscillations and the other more realistic load modeling of sea-states by means of hardware-in-the-loop (HIL) real-time simulations. Temperature results from 4 different torque oscillation tests and 12 different sea-state tests provide rotor-heating information, obtained from multiple temperature sensor data within the HTS rotor, and are compared with data obtained from steady-state runs.

The New Generation of Superconductor Equipment for the Electric Power Grid

High-temperature superconductor (HTS) power equipment, such as power cables, synchronous condensers, fault current limiters (FCLs), and transformers, are poised to address key technical issues in the U.S. Power grid. This equipment is enabled by the successful development of robust long-length HTS wire, available commercially from a variety of manufacturers worldwide. Compared to conventional cables, HTS power cables offer higher capacity with minimal disturbance to neighboring underground infrastructure, and their low series impedance opens the opportunity for cost-effective power flow control with phase angle regulators. HTS cables are being actively prototyped worldwide. Based on technology developed for industrial and ship propulsion motors, an HTS synchronous condenser has been developed and successfully tested in the Tennessee Valley Authority (TVA) grid; this is the first HTS power equipment to be offered commercially. It addresses the growing need for dynamic reactive power compensation for grid stability and power quality. HTS FCLs and transformers are also in active development

Progress in HTS Power Applications in the United States

The field of high temperature superconducting (HTS) power applications is very active in the United States. On the one hand, it is driven by the needs of the electric power grid, which has suffered from declining investment for many years. HTS cables, reactive power devices and fault current limiters address power grid issues. An HTS-based dynamic synchronous condenser is the world's first commercial power product. On the other hand, there is great interest from the US military in applications such as ship propulsion motors, lightweight generators, gyrotron microwave sources and degaussing cables.

Application of high-temperature superconductor bulk in ship propulsion motor

Application of high-temperature superconductor bulk in ship propulsion motor

5 MW High Temperature Superconductor Ship Propulsion Motor Design and Test Results

American Superconductor has designed, built, tested and delivered to the U.S. Navy's Office of Naval Research (ONR) a 5MW, 230-RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor. The motor uses an air core armature winding and first generation HTS wire (BSCCO-2223) field winding. The goal of the motor development project was to validate the technologies required to design and build larger HTS ship propulsion motors, as well as to develop a motor production process that streamlines development time and minimizes cost. A commercial variable frequency drive is used to power the motor. The HTS field winding is cooled with G-M coolers with gaseous helium as the cooling medium in a closed cycle. The armature is cooled by MideP. The motor was delivered to the U.S. Navy in July 2003 and met or exceeded requirements in operation (up to the facility's testing limit of 2.5MW). The motor demonstrated both full torque and full speed operation in separate tests.

The Performance of a 5 MW High Temperature Superconductor Ship Propulsion Motor

A 5 MW, 230 RPM, 6-pole high temperature superconductor (HTS) ship propulsion motor is presently under test at the Center for Advance Power Systems (CAPS). This paper provides a summary of the key design features of the motor, predicted performance, factory test results and extended test results to date at CAPS. This motor was designed and built under the U.S. Navy's Office of Naval Research (ONR) funding (Contract #N00014-02-C-0190) to address the next generation of electric ship propulsion systems. HTS motors are characterized by high power density, quiet operation and high efficiency. HTS air-core motors have unique electrical characteristics and therefore require dynamic testing to validate all modes of operation. The test program at CAPS is designed to address dynamic performance and simulation of this class of propulsion motor. The motor has been operated at 5 MW load for over 3 hours at CAPS.

Development status of rotating machines employing superconducting field windings

Superconducting rotating machines have looked promising since multifilamentary niobium-titanium (NbTi) superconductors became available in the mid-1960s. Both dc homopolar and ac synchronous machines were successfully tested from the 1970s to the 1990s. Three different 70-MW generators were recently demonstrated by the SuperGM project in Japan. However, economic considerations with respect to competitive cost combined with the requirement for liquid helium cooling did not make these machines commercially attractive. On the other hand, high-temperature superconductors (HTSs) can operate at much higher temperatures (30-40 K), providing much larger thermal margin and simpler cooling systems. This refrigeration advantage has provided new impetus to the development of such machines for commercial applications. In the last few years, a number of superconducting rotating machines with HTS field windings have been demonstrated and several projects are currently transitioning to advanced development stages. HTS machines with ratings from a few kilowatts to several megawatts have been demonstrated in the United States and Europe. Currently, large high-torque ship propulsion motors, large generator prototypes, and synchronous condensers are under development and are expected to be commercially available in the next few years. Prospects for improved life cycle cost, smaller size, less weight, and higher efficiency benefits are providing incentives for the development of these larger rating HTS machines. This paper reviews the past and recent progress on the worldwide development of industrial-grade superconducting rotating machines utilizing low-temperature superconductor and HTS field windings and provides an outlook on the benefits and opportunities of this new technology.

The Hunt for Compact Power

This article explains features of a ship propulsion motor with superconducting coils that hushes machinery noise and hollows out confined engine rooms. American Superconductor Corp. of Westborough, MA, announced plans to build a high-capacity manufacturing plant for its superconducting wire. This will move the company’s high temperature superconductor (HTS), wire from a developmental phase into large-scale production. IPS is exploring more than just propulsion motor technology. Engineers are evaluating the entire shipboard electrical system, from ship’s service power, to dc distribution, to power electronics—as well as the propulsion motor itself. The Navy, having decided upon electric drive for its next warship, has left the door open for superconducting motors. Superconducting motors can develop the same torque and horsepower within a motor frame that is nearly a third the size of a comparably rated conventional motor. The main factor leading to an HTS motor’s smaller size for a given horsepower output is the magnetic field strength that superconducting magnets create. Iron teeth, used to enhance magnetic flux in conventional rotors and stators, are not needed by superconducting motors.

Finite element modeling of the powder-in- tube process for manufacture of BSCCO-2212 superconducting wires

High-temperature superconductors have recently attracted a great deal of attention owing to their potential use in a variety of applications including power generators, superconducting magnets for mine sweepers or ship propulsion motors, and magnetic levitation transportation systems. The powder-in-tube (PIT) process has emerged as one of the most promising and economically feasible techniques to produce long lengths high-Tc oxide based superconducting wires. The PIT method involves multi-pass wire drawing followed by rolling and heat treatment. This work focuses on the development of finite element models to simulate the PIT drawing process for fabrication of silver sheathed Bi-2212 superconducting wires. The numerical models were used to predict the density of the oxide powder, the wire drawing forces, and the silver-oxide ratio during drawing. A cap-type pressure dependent constitutive equation was implemented in the model to simulate the powder behavior. The model incorporated experimentally obtained material data for the silver and powder. Data from wire drawing experiments were used to verify model predictions.

Large superconducting DC drives with separate torque reaction windings

A slotless-armature DC motor with multiplex winding can be designed for higher power rating compared to one with a conventional slotted armature. Conventional field systems would be very heavy and a superconducting field winding is considered in order to create an iron-free stator and lightweight machine. The superconducting field winding is relieved of reaction torque by means of a special winding attached to a separate torque tube. The reaction winding is also designed to establish the necessary commutation flux in the interpole region. Test results from a small laboratory machine demonstrate the principle of the proposed torque reaction winding. A design for a 20 MW ship propulsion motor is presented.