Design Methodology for the Field Orientation Control of a Non-linear Vector Controlled Sinusoidal Permanent Magnet Ac Motor

Nearly all of the electrical power used throughout the world is generated by synchronous machines driven by either hydro or steam turbines or by combustion engines. Synchronous Machine is generally dedicated to high power due to the fact that they have a controllable power factor and a higher efficiency than the induction motor of corresponding rating. In recent years different control schemes using synchronous motors operating from static power converter have been a real competitor to both DC and Induction Motor drives, especially in high power, low speed range. Among them field oriented control employing vector control strategies has become quite popular in recent years. A disadvantage of the scheme when applied to synchronous motor drive is that the motor always operates at a lagging power factor. In this work a generalized design strategy is suggested for speed control loop of an inverter fed synchronous motor drive, in which, its inherent flexibility to generate the same torque for different combinations of currents is exploited. The closed loop system for the Permanent Magnet AC Motor is simulated using MATLAB and the performance figures of some typical cases such as unity power factor control, torque angle control and internal angle control are obtained.