A New Dual-Buck Five-level Inverter with Coupled Inductors

  • 莊 銘凱

Student thesis: Master's Thesis


The input capacitors used in conventional multilevel inverters commonly experience a voltage-imbalance problem Accordingly the thesis proposes a new dual-buck inverter with coupled inductors to realize a five-level inverter consisting of single input capacitor a dual-buck module and a full-bridge module With the coupled inductors the inverter ensures an improved sinusoidal voltage to the load In addition the dual-buck module enhances system reliability by solving the shoot-through problem existing in conventional circuits The proposed dual-buck module comprising two diodes and two power switches generates a three-level voltage which is then converted to a five-level sinusoidal voltage by the full-bridge module A modulation method is developed accordingly for the proposed inverter with various switching patterns analyzed Via the presented modulation method no dc offset exists in the magnetizing inductor currents and problems of core saturation can thus be avoided The performance of the proposed converter is evaluated by the implemented prototype circuit with an input dc voltage of 380 V an output ac voltage of 220 Vrms and an input power of 1 5 kW The experimental results show that the output voltage total harmonic distortion (THD) of 1 2 % at full load condition and a highest efficiency of 94 7% have been achieved to validate the feasibility and effectiveness of the proposed multilevel inverter
Date of Award2014 Aug 22
Original languageEnglish
SupervisorHong-Tzer Yang (Supervisor)

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