A. Field Oriented Control principle of PMSM
So far, two main strategies which was widely used in the
PMSM speed control system were vector control strategyand direct torque control strategy, respectively.The basicidea of the vector control was to establish on the rotationalcoordinates and motor electromagnetic torqueequation[1].The current control of achieving permanent
magnet synchronous motor vector control system mainly hadthree approaches: Id=0,Torque current ratio and power factorequivalent to 1.What the control strategy of the controlleradopted was Id=0,and also was known as magnetic fieldorientation control.This control method which was widely
used was simple, small amount of calculation, and not haddirect axis armature reaction to the motor demagnetizationproblem. Hence,the driver of the permanent magnet
synchronous motor of actual design was shown as Fig.1.