A permanent magnet synchronous motor drive based on a current controlled cascaded multilevel inverter / Mohammed Adel Dia Eldin Shaltout ; Supervised Mahmoud Abdelhakim , Mostafa Ibrahim Marei

Thesis (M.Sc.) - Cairo University - Faculty of Engineering - Department of Electrical Power and Machines

Permanent magnet synchronous motor is becoming a very popular choice in drive technology due to some of its inheriting features. These features include high torque to current ratio, high power to weight ratio, high efficiency and robustness. However, PMSM has some limitations such as lack of starting torque, constant speed and low maximum torque. The lack of starting torque and fixed speed limitations has been overcome by feeding the permanent magnet motor with variable frequency inverter which can start the motor with gradual increase in the frequency and control the speed with the frequency control of the inverter. Among the various types of inverters, a current controlled inverter is used since it provides a direct method to control the electromagnetic torque and thus to yield better dynamic response. However, inverters usually introduce high harmonics both in the motor and supply sides. These harmonics, increases the motor losses and inflect harmonic burden on the supply. Therefore, a multilevel inverter is introduced to limit the harmonics

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