Design for Phase-shifted Carrier Pulse Width Modulation of Cascaded H-bridge Multi-level Inverters with Non-equal DC Voltages
Cai Xinjian1-3,Wu Zhenxing3,Sun Le4,Wang Shuxiu2
1.State Key Laboratory of Advanced Electromagnetic Engineering and Technology Huazhong University of Science and Technology Wuhan 430074 China 2.College of Information Science and Engineering Fujian University of Technology Fuzhou 350118 China 3.National Key Laboratory for Vessel Integrated Power System Technology Wuhan 430032 China 4.School of Electrical Engineering Xi’an Jiaotong University Xi’an 710049 China
Abstract：In practice,many factors result in non-equal cell DC voltages of the cascaded H-bridge multilevel (CHBML) inverter,such as the differences amongthe DC sources of the H-bridge cells and the faults of the DC sources.The classical phase-shifted carrier (PSC) pulse width modulation (PWM) is unable to eliminate the low-frequency sideband-harmonics when the DC voltages of the cells are not equal.The quality of the output voltage degrades.In this paper,the relationship among the cell carrier-phases,the DC voltages,and the harmonics of the output voltage are analyzed.And then,a novel PSCPWM method,in which the carrier phases are regulated according to the different DC voltages,is proposed.This method improves the quality of the output power by eliminating the low-frequency sideband harmonics,and also enhances the fault-tolerance capability of the inverters.The simulation and experimental results obtained from the prototype of the CHBML inverter verify the suggested regulation strategy.
蔡信健,吴振兴,孙乐,王书秀. 直流电压不均衡的级联H桥多电平变频器载波移相PWM调制策略的设计[J]. 电工技术学报, 2016, 31(1): 119-127.
Cai Xinjian,Wu Zhenxing,Sun Le,Wang Shuxiu. Design for Phase-shifted Carrier Pulse Width Modulation of Cascaded H-bridge Multi-level Inverters with Non-equal DC Voltages. Transactions of China Electrotechnical Society, 2016, 31(1): 119-127.
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2016, Vol. 31 
