本論文之主要目的在於設計以及實現一具有中性點電壓平衡的二極體箝位式三階變頻器。三階變頻器之輸出電壓諧波量較二階變頻器來的低,然而,二極體箝位式三階變頻器卻存在中性點電壓平衡的問題。本文採用兩種控制方法來平衡變頻器直流鏈電容之電壓,以證明本文所採用的方法能有效平衡中性點電壓,並降低輸出波形的總諧波失真量。 本論文的模擬結果採用Matlab®/Simulink® 軟體所建立之系統做分析,實驗結果則採用數位訊號處理器板作為系統核心,來控制並驅動感應馬達。經模擬與實驗結果均證實所採用的控制方法可以有效改善二極體箝位式三階變頻器中性點電壓平衡的問題,驗證控制方法的可行性。
The purpose of this thesis is to design and realize a diode-clamped three-level inverter with neutral-point voltage balance. The harmonic contents of output voltage of three-level inverters are less than those for two-level inverters. However, diode-clamped three-level inverter has the problem of neutral point voltage balance. This thesis uses two control methods to balance the voltage of DC-link capacitors and reduce the total harmonic distortion of output waveforms. The simulation results are derived from Matlab®/Simulink® software. The experimental results are derived from an induction motor drive controlled by digital signal processor. It will be shown that the simulation results and experimental results confirm the performance of the control methods for neutral point voltage balance in diode-clamped three-level inverters.