30 Years Space Vectors, 20 Years Field Orientation, 10 Years Digital Signal Processing with Controlled AC-Drives, a Review (Part 1)

SummaryThe dynamic interactions of AC-machines are far more complex than those of DC-machines and important quantities are not directly measurable. This has given rise to considerable difficulties in designing high performance AC-drive controls. About 20 years ago, they were overcome by the emergence or new methods of control, using moving frames of reference determined by the angular position or flux waves, hence called field orientation. Their application requires extensive on-line signal processing that can only be realised economically with microprocessors or special digital hardware.The paper presents a review of this evolution, which has matured in less than 2 decades from research studies to a universally accepted method for controlling AC-machines. The method of field orientation has proved to be well adaptable to all types of power converters and AC-machines; modifications and extensions to include self-tuning and adaptive features are possible. It now seems to be generally accepted that field orientation in one of its many forms is the most promising control method For high dynamic performance AC-drives.