TY - JOUR
T1 - A Cascaded Half-Bridge Three-Level Inverter With an Inductive DC-Link for Flexible Voltage Boosting
AU - Chen, Manxin
AU - Yang, Yongheng
AU - Loh, Poh Chiang
AU - Blaabjerg, Frede
PY - 2022/5
Y1 - 2022/5
N2 - Voltage boosting three-level inverters may present a monotonically increasing or decreasing voltage gain when enlarging the pulsewidth modulation (PWM) ratio. To produce a flexible voltage gain, this article proposes a novel three-phase three-level PWM inverter by cascading a traditional two-level three-leg (B6) inverter with half-bridges. The proposed inverter is supplied by an inductive dc-link consisting of a dc source in series with an inductor that is charged by shooting through the half-bridges in the B6 structure. The voltages across the cascaded half-bridges are subsequently boosted, and the output voltage is stepped up due to the cascaded connection. A moderate voltage gain is achieved with proper selections of two modulation variables while maximizing the PWM ratio. In particular, when the two modulation variables are equal, a constant voltage boosting gain of two is maintained irrespective of the PWM ratio. Additionally, low voltages are induced on the components, which facilitates the use of low-voltage devices. The operating principle of the proposed inverter with a modified third-harmonic-injection PWM scheme is presented, followed with theoretical analysis, comparison, and design considerations. Experimental tests on a 1.5-kVA inverter prototype verify its feasibility.
AB - Voltage boosting three-level inverters may present a monotonically increasing or decreasing voltage gain when enlarging the pulsewidth modulation (PWM) ratio. To produce a flexible voltage gain, this article proposes a novel three-phase three-level PWM inverter by cascading a traditional two-level three-leg (B6) inverter with half-bridges. The proposed inverter is supplied by an inductive dc-link consisting of a dc source in series with an inductor that is charged by shooting through the half-bridges in the B6 structure. The voltages across the cascaded half-bridges are subsequently boosted, and the output voltage is stepped up due to the cascaded connection. A moderate voltage gain is achieved with proper selections of two modulation variables while maximizing the PWM ratio. In particular, when the two modulation variables are equal, a constant voltage boosting gain of two is maintained irrespective of the PWM ratio. Additionally, low voltages are induced on the components, which facilitates the use of low-voltage devices. The operating principle of the proposed inverter with a modified third-harmonic-injection PWM scheme is presented, followed with theoretical analysis, comparison, and design considerations. Experimental tests on a 1.5-kVA inverter prototype verify its feasibility.
KW - Cascaded half-bridge (ChB)
KW - renewable energy applications
KW - third-harmonic-injection pulsewidth modulation (THI PWM) scheme
KW - three-level inverter
KW - voltage boosting
UR - http://www.scopus.com/inward/record.url?scp=85107350443&partnerID=8YFLogxK
U2 - 10.1109/TIE.2021.3084159
DO - 10.1109/TIE.2021.3084159
M3 - Journal article
SN - 0278-0046
VL - 69
SP - 4901
EP - 4913
JO - I E E E Transactions on Industrial Electronics
JF - I E E E Transactions on Industrial Electronics
IS - 5
M1 - 9446619
ER -