الفهرس 
Chapter 1: Control Methods of PMSM DrivesOnly 14 pages are availabe for public view
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Abstract
High performance motor drives require fast and accurate response, quick recovery from any disturbances, and insensitivity to parameter variations. The dynamic behavior of an ac motor can be significantly improved using vector control theory where motor variables are transformed into an orthogonal set of d–q axes such that speed and torque can be controlled separately. This gives the interior permanent magnet synchronous motor (IPMSM) the highly desirable dynamic performance capabilities of a separately excited dc machine, while retaining the general advantages of the ac over dc motors. The controller design of such a system plays crucial role in the system performance. The decoupling characteristics of a vector-controlled IPMSM are adversely affected by the parameter changes. Traditionally, these control issues are handled by the conventional proportional–integral (PI) controller and other controllers. However, parameter variations of the IPMSM leads to a cumbersome design approach for these controllers which always diminish the performance quality of the pre-design of the motor driving system. Precise speed control of an IPMSM drive becomes a complex issue due to nonlinear coupling among its winding currents and the rotor speed as well as the nonlinearity present in the electromagnetic developed torque due to magnetic saturation of the rotor core. Although these fixed gain controller have been using in industry for a long time because of simplicity and ease to implement in real-time. However, conventional controllers such as PI, PID are not suitable for high performance drives. Since these controllers are very sensitive to plant parameter variations, load disturbance and any other kinds of disturbances. To overcome such a limitation, a speed controller using a feedforward load torque compensator is presented This thesis presents a PI speed controller in conjunction with a feedforward load torque compensator of IPMSM drives. The load torque estimator is used to provide a feedforward value in the speed controller in order to decouple the load torque from the speed control. This method can improve the IPMSM dynamic performance against the disturbance torque without increasing the speed controller gain due to stability limitations. This can be achieved by dividing the electromagnetic torque in a feedforward value which should compensate the load torque, and a dynamic value which takes account of the speed variation. The load torque estimator compensates the speed control by setting a feedforward torque value through the q-axis current reference value. Therefore, the speed controller reaches immediately the speed reference value and a better response to load torque variations, which are detected and compensated leading to small speed variations, is obtained. In order to verify the effectiveness of the proposed IPMSM drive, at first simulation model is developed using Matlab/Simulink. Then, the complete IPMSM drive incorporating the proposed control algorithm has been successfully implemented using digital signal processor (DSP) control board-DS1102. The proposed controller with load torque compensator is examined through both simulation and experiments at different operating conditions. The performance of IPMSM drive system with a conventional PI controller is presented in comparison to the proposed controller.
The results show a significant improvement of the proposed controller, particularly during load torque variations and parameter variations.