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DESIGN AND CONTROL OF A HIGH-EFFICIENCY DOUBLY-FED BRUSHLESS MACHINE FOR POWER GENERATION APPLICATIONS

Guan, Bo
http://rave.ohiolink.edu/etdc/view?acc_num=osu1406240037

Abstract Details

2014, Doctor of Philosophy, Ohio State University, Electrical and Computer Engineering.
Due to its similar terminal characteristics like a wound-rotor Doubly-Fed Induction Machine (DFIM) and rugged rotor structure without brushes and slip rings, the Doubly-Fed Brushless Machine (DFBM) has attracted much attention for years, especially in the applications of variable-speed constant-frequency power generation and in adjustable speed drive system. However, the theory and modeling of DFBM still have not been sufficiently developed. Suffering from inherent deficiencies such as low mutual coupling between two windings, difficulties in rotor structure design and non-optimized control, the DFBM made an impression of low torque density and lower energy efficiency. The research objectives of this dissertation are to: (1) give a systematic and quantitative analysis of the mechanism, modeling and control of DFBM; and (2) design and build a high-efficiency DFBM based doubly-fed power generation system. Firstly, a detailed nonlinear analysis of DFBM by using the Finite Element Analysis (FEA) method is given. The mechanism of electromechanical energy conversion of the DFBM is investigated through the analysis of internal magnetic flux distribution, and of terminal characteristics of winding flux linkage and induced speed voltage (Back-EMF). The proposed harmonic decomposition method is utilized for the quantitative analysis of the asymmetric, non-sinusoidal and pulsating air-gap flux density, and assists in the evaluation of the “modulation” capability of the DFBM. Secondly, the mathematic models of DFBM in both dynamic and steady state conditions are systematically examined. The results of the study confirm the previous findings by the FEA and contribute to a quantitative analysis of the mathematic model of DFBM. The deduced dynamic and steady state equivalent circuits suggest that the DFBM has the same form and similar expression of mathematical model as those of a conventional DFIM. After the modeling of DFBM, the basic concept of field orientation control of torque and flux (and decouple control of active and reactive power) is introduced and analyzed in the steady state conditions. Then, the dynamic responses of the field orientation are discussed with the highlights of transient characteristics and expression of the flux linkage and torque. The implementation of the field orientation is also investigated. Finally, the latest investigation of optimal design and advanced control results of DFBM are presented. The challenges of designing a high-efficiency DFBM system are discussed in detail with the identified solutions of the optimal design and control. Using design principles assisted by FEA, an original design of a 200kW radially-laminated reluctance DFBM system is achieved, capable of 2,000 N.m in the speed range of 400 - 1,200 rpm, with a frame size comparable to that of a brush-type DFIM. The designed machine is built and tested in both a steady state and in dynamic conditions, and the experimental results are suitably agreed with the design objectives. The most successful results include the DFBM power delivery with more than 25% overload capability and energy efficiency higher than 90%, occupying 75% of the designed torque-speed regime. The theoretical and experimental results represent breakthroughs in doubly-fed brushless technology. The feasibility of DFBM technology for practical application is fully established.
LONGYA XU (Advisor)
JIN WANG (Committee Member)
MAHESH ILLINDALA (Committee Member)
133 p.
Electrical Engineering

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Citations

  • Guan, B. (2014). DESIGN AND CONTROL OF A HIGH-EFFICIENCY DOUBLY-FED BRUSHLESS MACHINE FOR POWER GENERATION APPLICATIONS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406240037

    APA Style (7th edition)

  • Guan, Bo. DESIGN AND CONTROL OF A HIGH-EFFICIENCY DOUBLY-FED BRUSHLESS MACHINE FOR POWER GENERATION APPLICATIONS. 2014. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1406240037.

    MLA Style (8th edition)

  • Guan, Bo. "DESIGN AND CONTROL OF A HIGH-EFFICIENCY DOUBLY-FED BRUSHLESS MACHINE FOR POWER GENERATION APPLICATIONS." Doctoral dissertation, Ohio State University, 2014. http://rave.ohiolink.edu/etdc/view?acc_num=osu1406240037

    Chicago Manual of Style (17th edition)

osu1406240037
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© 2014, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.