Thesis Defense - Koray Yoldaş (MSEE)

Koray Yoldaş - MSc., Electrical Electronics Engineering

Ahmet Tekin - Advisor

An Improved speed Controller for PMSM Drive with Unbalanced Load Using Load Torque Observer

Date: 22.05.2019

Time: 10:00

Location: AB2 130

Thesis Committee: 

Asst.Prof. Ahmet Tekin,  Ozyegin University

Asst. Prof. Göktürk Poyrazoğlu,  Ozyegin University

Asst. Prof. Özkan Akın,  Ege University

Abstract

In order to overcome disturbance effects as load torque variations in Permanent Magnet Synchronous Motor (PMSM), an improved controller with feed-forward compensation is presented in this study. Washing machines which are a good application area of both variable loads and low-high speed operations is chosen to examine the effectiveness of the proposed method. Firstly, a mathematical model of permanent magnet synchronous motor and torque expressions of the washing machine is reviewed. The Field Oriented Control is introduced with the Clarke and Park Transformations. Implementing the Field Oriented Control algorithm requires motor speed and rotor position information. In order to obtain these parameters, sensorless observer approach is used. Then for using in feedforward compensation of PMSM control system, load torque observer techniques have been studied. The observed torque is used as feedforward in axis current PI controller to compensate for the output of the speed PI controller caused by the unbalanced load profile of the washing machine. Motor speed information is required in both sensorless motor control algorithm and in proposed feedforward compensation with load torque observer. In order to get the best improvement by compensation, Extended Luenberger Observer, Direct Integration and Sliding Mode Observer methods are introduced with improvements for obtaining the motor speed. Simulation and experimental results are shown that in an operating system with disturbances as washing machines, PI controller response time can be improved by adopting an accurate feedforward scheme. Thus, energy efficiency performance, acoustical noise level and vibration performance of the washing machine can be improved by this method.

Bio

Koray Yoldas received his B.Sc. degree from Electrical and Electronics Engineering Department of Ege University, Izmir, Turkey, in 2015. He has been working at VESTEL Washing Machine Plant as R&D Engineer since 2015. His research interests are motor control systems, software design, and power electronics.