New Selective Harmonic Elimination-Pulse-Width Modulation for Cascaded H-bridge Multilevel Inverters

Author(s):  
Piyush L. Kamani ◽  
Mahmadasraf A. Mulla

AbstractThis paper presents a univariate equation-based selective harmonic elimination-pulse-width modulation (USHE-PWM) method for cascaded H-bridge (CHB) multilevel inverters (MLIs). Using equal-area criteria, the selection of voltage rating of dc-links have been done. The output voltage is controlled by inserting switching notch at the centre of each level of output voltage. Instead of conventional transcendental SHE-PWM equations, all these calculations are accomplished using univariate equations. This simplifies the real-time implementation of the proposed method greatly, even for the MLI with a large number of levels. The USHE-PWM method can eliminate more harmonics compared with the conventional SHE-PWM methods. While controlling the output voltage, the harmonic pattern remains unaffected. The validity of the proposed method is confirmed by the simulation and experimental studies.

2012 ◽  
Vol 5 (9) ◽  
pp. 1904-1911 ◽  
Author(s):  
N. Farokhnia ◽  
S.H. Fathi ◽  
R. Salehi ◽  
G.B. Gharehpetian ◽  
M. Ehsani

2021 ◽  
Author(s):  
Baharuddin Ismail ◽  
Muzamir Isa ◽  
M. Z. Aikhsan ◽  
M. N. K. H. Rohani ◽  
C. L. Wooi ◽  
...  

Electronics ◽  
2020 ◽  
Vol 9 (2) ◽  
pp. 263
Author(s):  
Manyuan Ye ◽  
Wei Ren ◽  
Qiwen Wei ◽  
Guizhi Song ◽  
Zhilin Miao

Asymmetric Cascaded H-bridge (ACHB) level inverters can output more voltage waveforms with fewer cascaded units while ensuring the quality of output voltage waveforms, so they have attracted more and more attention. Taking the topology of Type-III asymmetric CHB multilevel inverters as the research object, a Modified Hybrid Frequency Pulse Width Modulation (MHF-PWM) strategy is proposed in this paper. This modulation strategy overcomes the local overshoot of low-voltage unit in the presence of traditional Hybrid Frequency Pulse Width Modulation (HF-PWM), thus completely eliminating the low frequency harmonics in the output voltage waveform of Type-III ACHB nine-level inverters, and the Total Harmonic Distortion (THD) of output line voltage of the modulation strategy is lower than that of PS-PWM strategy in the whole modulation degree, which effectively improves the quality waveform of the output line voltage. At the same time, the strategy can also improve the problems of current backflow and energy feedback caused by the high-voltage unit pouring current to the low-voltage unit, thereby reducing the imbalance of the output power of the high-voltage and low-voltage units. Finally, the Matlab/Simulink simulation model and experimental platform are established to verify the validity and practicality of the modulation strategy.


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