Abstract:Cascade multilevel converter is applied in large capacity power electronics equipment increasingly. DC link fluctuation can bring output voltage distortion of cascade multilevel converter, which can increase low harmonic component, decrease the input/output linearity and produce torque pulsation for motor load. Based on the detailed analysis of the effect on output voltage of DC link fluctuation, PWM with amplitude-adjustable carrier is proposed in this paper. This technique will adjust carrier amplitude betimes according to the actual change of DC link voltage, which can effectively restrain output voltage distortion brought of DC link fluctuation. Technique of PWM with amplitude-adjustable carrier is significant to improve system performance and power density due to its simple principle and easy implementation, and reduced demand of DC link filter capacitor. Theoretical analysis and simulation study are verified by experimental results.
王立乔, 杨博生, 邬伟扬. 载波幅值可调PWM技术及其在级联型多电平变流器中的应用[J]. 电工技术学报, 2010, 25(11): 122-128.
Wang Liqiao, Yang Bosheng, Wu Weiyang. PWM With Amplitude-Adjustable Carrier and Its Application in Cascade Multilevel Converter. Transactions of China Electrotechnical Society, 2010, 25(11): 122-128.