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Modeling and Control of Dual Mechanical Port Electric Machine

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Modeling and Control of Dual Mechanical Port Electric Machine MODELING AND CONTROL OF DUAL MECHANICAL PORT ELECTRIC MACHINE DISSERTATION Presented in Partial Fulfillment of the Requirements for the Degree Doctor of Philosophy in the Graduate School of The Ohio State University By Haiwei Cai Graduate Program in Electrical and Computer Science The Ohio State University 2015 Dissertation Committee: Dr. Longya Xu, Advisor Dr. Jin Wang, Dr. Mahesh Illindala Copyright by Haiwei Cai 2015 Abstract The Dual Mechanical Port (DMP) electric machine has two rotors that can be controlled to rotate in different speeds and directions. Compared with conventional electric machines with only one rotor, the DMP machine provides higher torque density and much better control flexibility. However, the DMP machine also has relatively complex structure, which bring challenges to the modeling and control of the machine. The existing model and control algorithms for single rotor electric machines cannot be applied to the DMP machine directly. In this work, the application of DMP machine on hybrid electric vehicle will be used as an example to explain the electromagnetic characteristics and functionality of the DMP machine. The model and the control algorithms for two different DMP machines are investigated. The first DMP machine uses two layers of Permanent Magnets in the outer rotor; it is called the PMDMP machine. The second DMP machine uses single layer of Squirrel Cage in the outer rotor; it is called the SCDMP machine. The study on modeling and control for the SCDMP machine is the major contribution of this work. The PMDMP machine stands out for its high torque density and high efficiency when compared with other DMP machines. Detail model derivation for the PMDMP machine is presented. The independent control of its two rotors is investigated and verified by simulations and experiments. To overcome the problems brought by the position sensors, ii position sensorless control algorithms for the PMDMP are also investigated. High frequency injection and sliding mode sensorless control algorithms are applied to the PMDMP machine at low speed and high speed, respectively. The performance of the sensorless control algorithms in experiments matches well with the simulation results. To verify the functionality of the DMP machine in power split hybrid application, the power flow pattern in various operational modes are discussed and simulated. In order to avoid using the high cost rare earth permanent magnets, the SCDMP machine is proposed. This DMP machine replaces the permanent magnets in the outer rotor with a squirrel cage. Since this DMP machine has a squirrel-cage outer rotor, it is named as SCDMP machine. First, the electromagnetic characteristic of the SCDMP machine is analyzed. Then, the transient model and steady-state model of the SCDMP machine are derived. The proposed machine models are verified by finite element method and simulation. The results show that the proposed models accurately represent the unique electromagnetic characteristics of the SCDMP machine. Due to its unique electromagnetic characteristics, control algorithms for conventional machines cannot be applied to the SCDMP machine. The methods to calculate the correct current commands and to estimate the outer rotor flux position are proposed. Based on these two methods, a control algorithm for the SCDMP machine is proposed and estimated by simulation. The results show that the proposed control algorithm is able to independently control the torque productions and the flux levels of the two rotors of the SCDMP machine. iii Dedication This document is dedicated to my family and all the people that I love. iv Acknowledgments I would like to express my deepest gratitude to my adviser, Dr. Longya Xu, for his insightful academic guidance and consistent funding support during my graduate study. Dr. Xu set a great example of an excellent researcher for me and helped me develop critical and independent thinking skills, which will be beneficial throughout my life. I also want to thank Dr. Xu for providing me the chance to freely explore different research topics. Without his encouragement and patience, this dissertation would not have been possible. I would like to thank Dr. Jin Wang and Dr. Mahesh Illindala for being committee members of my graduate study. They provided me many insightful comments and constructive suggestions in the review of my research proposal and dissertation. My special thanks go to Dr. Vadim Utkin as well for his invaluable advice in my Candidacy Exam. My thanks are extended to my fellow colleagues Dr. Dakai Hu, Dr. Yazan Alsmadi, Dr. Yu Liu, Dr. Kaichien Tsai, Dr. Zhendong Zhang, Dr. Bo Guan, Mr. Ying Xiao, Mr. Feng Qi, Mr. Miao Wang, Mr. Jianyu Pan, Mr. Alejandro Pina Ortega, Mr. Qi Chen and Mr. Han Yang for their generous help and friendship during my study at the Ohio State University. v Vita September 2006 – July 2010 ........................ B.S. Electrical Engineering & Automation, South China University of Technology, Guangzhou, China September 2010 – August 2012 ................... Master’s Student, Graduate Fellow, The Ohio State University, Columbus, Ohio May 2015 – August 2015 ............................. Systems Engineer, Summer Intern, Nexteer Automotive, Saginaw, Michigan September 2012 – present ............................ PhD Student, Graduate Research Associate, The Ohio State University, Columbus, Ohio Publications H. Cai and L. Xu, "Modeling and Control for Cage Rotor Dual Mechanical Port Electric Machine–Part I: Model Development," in Energy Conversion, IEEE Transactions on , vol.30, no.3, pp.957-965, Sept. 2015. H. Cai and L. Xu, "Modeling and Control for Cage Rotor Dual Mechanical Port Electric Machine—Part II: Independent Control of Two Rotors," in Energy Conversion, IEEE Transactions on , vol.30, no.3, pp.966-973, Sept. 2015. H. Cai, B. Guan and L. Xu, "Low-Cost Ferrite PM-Assisted Synchronous Reluctance Machine for Electric Vehicles," in Industrial Electronics, IEEE Transactions on , vol.61, no.10, pp.5741-5748, Oct. 2014. H. Cai and L. Xu, "Control principle of Dual Mechanical Port electric machine with Squirrel-Cage outer rotor," in Transportation Electrification Asia-Pacific (ITEC Asia- Pacific), 2014 IEEE Conference and Expo , vol., no., pp.1-6, Aug. 31 2014-Sept. 3 2014. vi H. Cai and L. Xu, "Modeling of dual mechanical port machine with squirrel-cage outer rotor for hybrid electric vehicles," in Energy Conversion Congress and Exposition (ECCE), 2014 IEEE , vol., no., pp.4888-4895, 14-18 Sept. 2014 H. Cai, B. Guan, L. Xu and W. Choi, "Optimal design of synchronous reluctance machine: A feasible solution to eliminating rare earth permanent magnets for vehicle traction applications." COMPEL: The International Journal for Computation and Mathematics in Electrical and Electronic Engineering 33.5 (2014): 1569-1586. Q. Ahmed, H. Cai, G. Rizzoni and L. Xu, "Modeling and Control of a Novel Power Split Hybrid Electric Vehicle." ASME 2014 Dynamic Systems and Control Conference. American Society of Mechanical Engineers, 2014. H. Cai, L. Xu, "Maximum Torque Control of Induction Machine in Deep Flux Weakening Region," in Energy Conversion Congress and Exposition (ECCE), 2015 IEEE , vol., no., pp.3928-3933, 20-24 Sept. 2015 A. Pina, H. Cai, Y. Alsmadi, L. Xu, “Analytical Model for the Minimization of Torque Ripple in Permanent Magnets Assisted Synchronous Reluctance Motors Through Asymmetric Rotor Poles”, in Energy Conversion Congress and Exposition (ECCE), 2015 IEEE , vol., no., pp.5609-5615, 20-24 Sept. 2015 Fields of Study Major Field: Electrical and Computer Engineering vii Table of Contents Abstract .......................................................................................................................... ii Dedication ..................................................................................................................... iv Acknowledgments ...........................................................................................................v Vita ............................................................................................................................... vi Publications ................................................................................................................... vi Fields of Study ............................................................................................................. vii Table of Contents ........................................................................................................ viii List of Tables................................................................................................................. xi List of Figures .............................................................................................................. xii Nomenclature ...............................................................................................................xvi Chapter 1: Introduction ...................................................................................................1 1.1 Background of research ..........................................................................................1 1.2 Literature review ....................................................................................................4 Chapter 2: Permanent Magnet Dual Mechanical Port Electric Machine .......................... 10 2.1 Modeling of PMDMP machine ............................................................................. 10 viii 2.1.1 Introduction of PMDMP machine .................................................................
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