Analysis, design and control of permanent magnet synchronous motors for wide-speed operation

Ph.DDOCTOR OF PHILOSOPH

A low cost, high performance pc based integrated real-time motion control development system.

The control of electrical drives, or motion control, is important in modern industry. In order to satisfy the requirements of industry, it is important for tertiary institutions to produce graduates skilled in this field. The theoretical content of a typical electrical engineering course will prepare students to tackle design and offline simulation of a digital motion controller. However, to gain an in-depth understanding of the field, students need to be able to implement and test their designs in practice. The complete design process of a digital motion controller is an inherently lengthy process requiring a number of diverse skills, for example microprocessor based hardware and software design. While hardware design issues can be minimised by a choice of a commercially available controller board, the coding of real-time software for a complex controller can pose a steep learning curve. At the undergraduate level, students seldom will possess sufficient practical expertise to fully implement a challenging motion control design in the limited time frames allocated for such projects. This thesis presents a complete rapid prototyping environment for the design of motion control, the Control System Development Environment (CSDE). The CSDE allows a seamless progression of a motion control project through all stages, from initial design and simulation, through real-time implementation to final online tuning and validation. Users are freed from all low-level software and hardware design issues. In the context of undergraduate design projects, the CSDE allows students to design, simulate and prototype challenging solutions in the limited time available. Thus, students can gain in-depth, system level expertise in the design of motion control without being hampered by low-level design issues. The CSDE has been successfully tested by a number of undergraduate students at the Department of Electrical Engineering at the University of Natal. In particular, the CSDE's effectiveness has been demonstrated by its application during two prize winning final year design projects

Adaptive feedforward cancellation viewed from an oscillator amplitude control perspective

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2003.Includes bibliographical references (p. 335-340).This thesis presents methods of characterizing the convergence, error, stability, and robustness properties of Adaptive Feedforward Cancellation (AFC) for use on fast tool servos in high-precision turning applications. Previous work has shown that classical control techniques can be used to analyze the stability and robustness of an AFC loop. However, determination of the convergence and error properties of the closed-loop system to changes in the reference or disturbance signal is not an obvious output of these analyses. We have developed a method of viewing AFC from an oscillator amplitude control (OAC) perspective, which provides additional use of classical control techniques to determine the convergence and error properties of the closed-loop system. AFC is a form of repetitive control that can be used to significantly improve periodic trajectory following/disturbance rejection. Fast tool servos used in high-precision turning applications commonly follow periodic trajectories and develop large errors, which usually occur at integer harmonics of the fundamental spindle rotation frequency. We have developed a loop-shaping approach to designing multiple resonator AFC controllers and have implemented this design on a commercially available piezoelectric (PZ) driven FTS using a PC-based digital control system. Our view of Adaptive Feedforward Cancellation from an oscillator amplitude control perspective builds upon previous work in the literature. We use an averaging analysis to simplify the single resonator AFC system into two coupled single-input single-output (SISO) oscillator amplitude control loops and show that by using the correct rotation matrix, these loops are effectively decoupled. This simplification provides the use of classical control techniques to approximate the dynamics of the closedloop output to changes in the amplitude or frequency of the reference/disturbance signal. The simulated and experimental results conform well to our analytical predictions for sufficiently low gain values.by Joseph Harry Cattell.S.M