TECHNOLOGY AREAS: Materials/Processes

ACQUISITION PROGRAM: ACAT 1, DDX Program, PMS 500IPS - Mike Collins

OBJECTIVE: Development of motor insulation materials/methods to allow for the application of pulse-width-modulated (PWM) adjustable speed power controllers for ship propulsion scale motor applications.

DESCRIPTION: In the past, large motors (20 MW and higher) have employed a fixed speed motor controller operating with a constant 60 HZ power waveform. More and more motor manufacturers have begun to use pulse-width-modulated (PWM) adjustable speed power converters in an effort to improve overall motor efficiency and controllability. However, the use of PWM converters introduces voltage stresses and harmonics that in turn lead to heating stresses that had not existed in fixed speed motor applications.

This topic seeks to explore the development of motor insulation materials/methods to allow the use of PWM technology in ship propulsion applications at voltages equal to or greater than 2 kV. This presents some unique technical challenges from the standpoint of the availability of viable motor insulation materials/methods. The primary challenge is in the balance between voltage breakdown, void filling, mechanical strength and thermal resistance. The material solution or method proposed should maximize the current capability without overheating the motor while at the same time creating a motor footprint that is supportable by the host platform. The solution proposed must address voltage, corona, and partial discharge withstand while providing a 25+ year operating life. Solutions should target a motor space and weight goal of 310 tons and 157 ft3 and should address general machinery arrangement configuration considerations to facilitate easy access for installation, maintenance and repair.

PHASE I: Demonstrate the feasibility of a motor insulation material/method. The concept feasibility should be supported by in-house generated experimental data, literature search results, and/or appropriate analytical modeling. Establish performance goals and metrics to analyze the feasibility of the proposed solution. Develop a test and evaluation plan that contains discrete milestones for product development for verifying performance and suitability.

PHASE II: Develop and demonstrate prototype materials/methods as identified in Phase I. In a laboratory environment, demonstrate that the prototype meets the performance goals established in Phase I. Material candidates should be tested using relevant IEC and IEEE test methods to determine if thermal performance has improved while still maintaining long electrical life. Develop a cost benefit analysis and a Phase III testing and validation plan.

PHASE III: Working with the Navy and industry, as applicable, transition the technology to commercial and military power distribution applications.

PRIVATE SECTOR COMMERCIAL POTENTIAL/DUAL-USE APPLICATIONS: The commercial shipping industry has been interested in the development and application of electric propulsion systems technology. This technology is a key enabler that would allow the use of PWM motors on higher power motor applications. This technology will also allow for increased motor insulation life for all PWM driven motor applications.

REFERENCES:
All references are available at http://ieeexplore.ieee.org/Xplore/guesthome.jsp

1. "DEALING WITH MOTOR WINDING PROBLEMS CAUSED BY INVERTER DRIVES" Mark Fenger, Steven R. Campbell, Iris Power Engineering Inc. Jan Pedersen, Techwise A/S.
2. M.T. Wright, S.J. Yang, and K. McCleay, General Theory of Fast-Fronted Interturn Voltage Distribution in Electrical Machine Windings, Proc. IEEE, Part B, July 1983, p 245.
3. B.K. Gupta, et al, Turn Insulation Capability of Large AC Motors, Parts 1, 2, 3, IEEE Trans EC, December 1987, p 658.
4. A.L. Lynn, W.A. Gottung, D.R. Johnston, Corona Resistant Turn Insulation in AC Rotating Machines, Proc. IEEE Electrical Insulation Conference, Chicago, October 1985, p 308.
5. E. Persson, Transient Effects in Applications of PWM Inverters to Induction Motors, IEEE Trans IAS, September 1992, p1095.

KEYWORDS: PWM; Motor Insulation; Insulators; Partial Discharge; Corona; Thermal Conduction

TPOC: Joseph Borraccini
Phone: (215)897-8797
Fax:
Email: [email protected]
2nd TPOC: Christopher Stack
Phone: (215)897-8922
Fax: (215)897-8936
Email: [email protected]

** TOPIC AUTHOR (TPOC) **

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