TY - GEN
T1 - Comprehensive comparison of THD and common mode leakage current of bipolar, unipolar and hybrid modulation schemes for single phase grid connected full bridge inverters
AU - Xia, Yinglai
AU - Ayyanar, Raja
N1 - Publisher Copyright:
© 2017 IEEE.
PY - 2017/5/17
Y1 - 2017/5/17
N2 - This paper presents a comprehensive analysis and comparison among the three commonly used PWM schemes for single phase full bridge inverters namely, bipolar, unipolar and hybrid modulation schemes. The inductor current ripple and THD are analyzed using time domain analysis methods and the performance of the three modulation schemes are compared in detail for a range of modulation indices. An interesting result is that in order to achieve the same THD, compared with unipolar PWM, the average switching frequency (considering all the switches) of hybrid PWM is same but the average switching frequency of bipolar PWM needs to be around 3.6 times, when the modulation ratio is between 0.6 and 1. This results in the corresponding increase in the device switching losses. The common mode voltage between the negative terminals of the input and the grid, and the resulting leakage current are also analyzed and compared among the three schemes. Finally, a SiC MOSFETs based 1 kW full bridge inverter using the three modulation schemes has been built to validate the theoretical analysis. The inductor current ripple, THD and common mode leakage current analysis are verified through experiment.
AB - This paper presents a comprehensive analysis and comparison among the three commonly used PWM schemes for single phase full bridge inverters namely, bipolar, unipolar and hybrid modulation schemes. The inductor current ripple and THD are analyzed using time domain analysis methods and the performance of the three modulation schemes are compared in detail for a range of modulation indices. An interesting result is that in order to achieve the same THD, compared with unipolar PWM, the average switching frequency (considering all the switches) of hybrid PWM is same but the average switching frequency of bipolar PWM needs to be around 3.6 times, when the modulation ratio is between 0.6 and 1. This results in the corresponding increase in the device switching losses. The common mode voltage between the negative terminals of the input and the grid, and the resulting leakage current are also analyzed and compared among the three schemes. Finally, a SiC MOSFETs based 1 kW full bridge inverter using the three modulation schemes has been built to validate the theoretical analysis. The inductor current ripple, THD and common mode leakage current analysis are verified through experiment.
KW - Bipolar
KW - Common mode leakage current
KW - Hybrid
KW - Modulation schemes
KW - THD
KW - Unipolar
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U2 - 10.1109/APEC.2017.7930777
DO - 10.1109/APEC.2017.7930777
M3 - Conference contribution
AN - SCOPUS:85019974358
T3 - Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC
SP - 743
EP - 750
BT - 2017 IEEE Applied Power Electronics Conference and Exposition, APEC 2017
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 32nd Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2017
Y2 - 26 March 2017 through 30 March 2017
ER -