published_or_final_version / Electrical and Electronic Engineering / Doctoral / Doctor of Philosophy

Thesis (M.S.)--Ohio University, November, 1996. / Title from PDF t.p.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Includes bibliographical references (p. 169-182) Also available in print.

Several new nonlinear algorithms for speed control of electrical drives are developed. They are compared with the algorithms for integral-proportional (I-P) control, sliding mode control (SLM) and adaptive control which uses the torque and parameter observer. To achieve fast and robust response, all algorithms use very large gains. In a new, variable limit PI (VLPI) control algorithm, integrator windup is completely prevented by using a high gain, "variable dead zone" nonlinearity as a local feedback over the integrator. Recently proposed soft variable structure (SVS) control, derived by using the Liapunov direct method, is modified so that the algorithm can be implemented with only the output measurements. Proper operation is achieved for any value of the output variable. The new control is very robust, but exhibits a steady state error. Two versions of the adaptive PI (API) control algorithm are developed that have fast and robust transient response with zero steady state error. The SVS API version operates similarly as the modified SVS control, but does not have its drawbacks. The SLM API version operates like the SLM control during large transients, and like VLPI control when close to the steady state. The local stability of the control is proved using the "small gain theorem". Its global behavior is analyzed by describing functions. Very good operation of the SVS API speed control within the proportional position loop is demonstrated. Faster transient response is achieved by implementing the SLM adaptive proportional control in the position loop. The operation is the same as the operation of the SLM API control in the speed loop. Similarity between modified SVS control, and classical adaptive algorithms is shown. API control, All the algorithms are simulated and compared for twofold and tenfold changes in plant parameters. The experimental verification of the results for I-P control, SLM control, and modified SVS control, are presented. Theory of the new algorithms is general, such that the results are applicable to any SISO plant that can be stabilized. / Ph. D.

M.S.

Permanent magnet brushless DC motors that have found wide application in high performance servo drives need absolute rotor position sensors. However, the cost of the position sensor limits the use of brush less DC motors for low performance applications such as automotive and home appliances. A sensorless starting scheme for brushless DC motors is studied in this thesis. A hardware implementation of the starting scheme has been instrumented. The modeling and simulation of the sensorless starting performance of brushless DC motors have been accomplished to gain the insight into the process. The experimental results confirm the theoretical prediction that the permanent magnet brush less DC motor can be started without a position sensor. The experimental setup with individual subsystems are described in detail. / Master of Science

Yeung Kin. / Thesis (M.Phil.)--Chinese University of Hong Kong, 2001. / Includes bibliographical references (leaves 86-89). / Abstracts in English and Chinese. / Abstract --- p.i / Acknowledgement --- p.iii / Tables of Contents --- p.iv / List of Figures --- p.vi / List of Tables --- p.vii / Chapter Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Distance Learning (DL) and Virtual Laboratory (VL) --- p.1 / Chapter 1.2 --- Overview of related research --- p.3 / Chapter 1.3 --- Web-based Control Laboratory --- p.5 / Chapter 1.4 --- Contributions of the Project --- p.8 / Chapter 1.5 --- Thesis Outline --- p.10 / Chapter Chapter 2 --- System Architectures --- p.11 / Chapter 2.1 --- Hardware Architecture --- p.11 / Chapter 2.1.1 --- Internal Distributed System --- p.12 / Chapter 2.1.2 --- Video Server System --- p.14 / Chapter 2.1.3 --- Application Systems --- p.15 / Chapter 2.2 --- Software Architecture --- p.17 / Chapter 2.2.1 --- Client Side Context --- p.17 / Chapter 2.2.2 --- Web Server Context --- p.19 / Chapter 2.2.3 --- Software Context in Controller PC --- p.24 / Chapter Chapter 3 --- System Attributes --- p.33 / Chapter 3.1 --- Protocol Attribute --- p.33 / Chapter 3.2 --- Client/Server Structure --- p.36 / Chapter 3.3 --- Multi-layer Structure --- p.39 / Chapter 3.4 --- Inter-process Flow Attribute --- p.41 / Chapter Chapter 4 --- Experiment Description --- p.43 / Chapter 4.1 --- Client Interface --- p.43 / Chapter 4.2 --- Experiments Implementation --- p.46 / Chapter 4.3 --- Controller Analysis --- p.47 / Chapter 4.3.1 --- System Theory --- p.47 / Chapter 4.3.2 --- PID Control --- p.49 / Chapter 4.3.3 --- Set Point Control by State Space Method --- p.51 / Chapter Chapter 5 --- System Characteristics --- p.54 / Chapter 5.1 --- Distance Learning --- p.54 / Chapter 5.2 --- Networking Issues --- p.55 / Chapter 5.3 --- Design Issues --- p.56 / Chapter 5.4 --- Security Issue --- p.56 / Chapter 5.5 --- Interface Issues --- p.57 / Chapter 5.6 --- Future Enhancement --- p.58 / Chapter Chapter 6 --- Impacts and Further Work --- p.59 / Chapter 6.1 --- Impacts on Web-based Laboratory --- p.59 / Chapter 6.2 --- Impacts on Society --- p.60 / Chapter 6.3 --- Future Work --- p.61 / Chapter Chapter 7 --- Conclusion --- p.63 / Appendices --- p.65 / Appendix I. Selected Source Code of Server Side Programs --- p.65 / Appendix II. Selected Client Experiment Interface --- p.81 / Appendix III. Laboratory Experiment Manual --- p.84 / Bibliography --- p.86