الفهرس 
الغلافOnly 14 pages are availabe for public view
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Abstract
Due to the increasing demand for compact and reliable motors and the evolution of lowcost power semiconductor switches and permanent magnet (PM) materials, brushless motors became popular in every application from appliance and automotive to medical, military products and aerospace industry. Unlike brushed DC motors, every brushless motor requires a ”drive” to supply commutated current to the motor windings synchronized to the rotor position. In other words, some kind of feedback position sensors is necessary to commutate brushless motors. PM brushless motor drives have sinewave and square wave versions. the sinwave PM brushless motor drive, also called the PM synclu•onous motor drive, is fed by sine wave current and uses continuous rotor position feedback signals to control the cOlmnutation. On the other hand, the squarewave PM brushless motor drive, also called the PM brushless dc motor drive, is fed by squarewave current and uses discrete rotor position ”feedback signals to control the commutation.
In this work, some details about PM brushless motors are introduced from point of view of classifications, advantages, construction, operation, comparing it with brushed motor and induction motors. This kind of motor not only has the advantages of DC motor such as better velocity capability and no mechanical commutator but also has the advantage of AC motor such as simple structure, higher reliability and free maintenance. In addition, brushless DC motor has the following advantages: smaller volume, high force, and simple system structure. So it is widely applied in areas which need high perfonnance drive.
from the control point of view, recently, many modern control methodologies such as nonlinear control, optimal control, vmiable structure control and adaptive control have been widely proposed for pennanent magnet brushless DC motor. However, these approaches are either complex in theoretical bases or difficult to implement. Proportional plus Integral plus Derivative (PID) controller with its three term functionality covering treatment to both transient and steady-state response specifications, offers the simplest and yet most efficient solution to many real world control problems. In spite of the simple structure and robustness of this method, optimally tuning gains of PID controllers have been quite difficult.