Abstract：For cascaded multilevel converter based power electronic transformer (PET), the unbalance of DC output voltage of each rectifier or power transmission in each dual active bridge (DAB) module may lead to uneven voltage or current stress among switches. This paper presents a strategy to solve voltage imbalance and power imbalance caused by parameter mismatch of each DAB module. Wherein, a voltage balance control strategy is adopted in multilevel rectifier stage, while a sensorless power balance control strategy is adopted for the modular DAB converter. Regarding the power balance realization, the active power component of the duty cycle in the rectifier stage is used as power feedback to adjust the duty cycle of each DAB module. These two control methods operate coordinately, to balance the DC output voltage of each rectifier and transfer power in each DAB module. Furthermore, the power balance control algorithm can be easily realized by DSP without current sensor. Finally, simulation and experimental data in a cascaded multilevel converter based PET have verified the proposed strategy.
王杉杉, 王玉斌, 林意斐, 于程皓, 李厚芝. 级联型电力电子变压器电压与功率均衡控制方法[J]. 电工技术学报, 2016, 31(22): 92-99.
Wang Shanshan, Wang Yubin, Lin Yifei, Yu Chenghao, Li Houzhi. Voltage and Power Balance Control for Cascaded Multilevel Converter Based Power Electronic Transformer. Transactions of China Electrotechnical Society, 2016, 31(22): 92-99.
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