Selection of suitable PWM switching and control methods for modular multilevel converter drives

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Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Mühendislik Fakültesi, Elektrik ve Elektronik Mühendisliği Bölümü, Türkiye

Tezin Onay Tarihi: 2014

Öğrenci: BARIŞ ÇİFTÇİ

Danışman: AHMET MASUM HAVA

Özet:

The thesis focuses on the determination of suitable carrier based PWM switching and control method for modular multilevel converter drives. Characterization of various level-shifted and phase-shifted carrier based PWM methods are provided in terms of switching pulse patterns and resultant voltage waveforms both for N+1 and 2N+1 level output phase voltages. Modular multilevel converter PWM based control approaches are evaluated. Performances of different control methods are given for output harmonics distortion, submodule capacitor voltage ripple, circulating current ac component, efficiency and other criteria under equal switching count principle, for the dc/ac conversion step of a 10MW HVDC transmission system. Moreover, a 9.1MW induction motor drive application is studied from standstill to full speed range, giving attention to low frequency region operation. The study is conducted by means of mathematical analysis of the converter, topological and controller design, and detailed computer simulations.