Power Ac - Ac Inverter Synchronous Motor Field Oriented Control System Design And Application

AC motor is differ from DC motor, its magnetometive force vector F~s, F~r and F~c all circumgyrate with the synchronization speed in the space, and rest each other oppositely. We must control the size and opposite position of arbitrary two of the magnetometive force vectors to control torque.The controlling quantity of usual frequency conversion adjusting speed system is the stator voltage breadth and frequency of the AC motor or the stator current breadth and frequency of the AC motor. As breadth and frequency all are scalar quantity, the system is named scalar quantity controlling system. In the scalar quantity controlling system, we can only control the motor with its steady state running rule, can not control the size and opposite position of arbitrary two of the magnetometive force vectors, the controlling capability of the torque is not good.To improve the controlling capability of torque, we must actualize vector controlling with stator voltage or stator current, control the size and direction at the same time. Usually, a vector is expressed by its two ponderances in the right-angle reference frame, all the vectors of AC motor (magnetometive force, magnet chain, voltage, current etc.) circumgyrate with the synchronization speed in the space, the ponderances of these vectors in the stator reference frame (stillness frame), namely the physical quantities of stator winding, all are AC quantities, it is not convenient to control. Recur to coordinate transform, man can go into synchronization circumgyrating reference frame from stillness reference frame, see while standing on the circumgyrating reference frame, all the vectors of motor become stillness vectors, all their ponderances on the reference frame are DC quantities, so it is convenient to find out the relations between torque and each ponderance of controlled vectors (voltage or current etc. vectors) by dint of unification torque formula, and work out real time the value of each ponderance (DC reference quantify) needed by torque controlling. As these DC ponderances of controlled vectors do not exist in physics, we must pass coordinate transform again, go back to the stillness frame from circumgyrating reference frame, change these DC reference quantifies into AC reference quantifies existing in physics, control these AC quantifies in stator reference frame, make their real values equal to reference values.From these argumentations, we can see, the key of vector control is the coordinate transform between stillness reference frame and circumgyrating...