TY - GEN
T1 - Control of the Modular Multilevel Converter for variable-speed drives
AU - Jung, Jae Jung
AU - Lee, Hak Jun
AU - Sul, Seung Ki
PY - 2012
Y1 - 2012
N2 - This paper presents a control strategy of the entire frequency range operation for Modular Multilevel Converter (MMC), especially focusing on variable speed drive of an AC machine. The structure of MMC essentially requires energy balancing control so as to mitigate the voltage pulsation of each cell capacitor in converter arms. In the proposed control strategy, two operation modes are employed. One is a low frequency operation mode for start-up and low speed operation of the AC machine, and the other is a normal frequency operation mode from medium to rated speed of the AC machine. To reduce the pulsation, this paper proposes the energy balancing control strategies at each operation mode. Theoretically, the energy balancing control of the capacitors is prone to be unstable at low frequency operation. In order to prevent the instability, a special control strategy is introduced. The strategy exploits a common mode voltage and a circulating current with high frequency component in low frequency operation mode. With the proposed control scheme, the speed control range of the AC machine driven by MMC can be down to zero speed without instability of voltage of the cell capacitors. Experimental results for the energy balancing control are shown to demonstrate the effectiveness of the proposed control strategy.
AB - This paper presents a control strategy of the entire frequency range operation for Modular Multilevel Converter (MMC), especially focusing on variable speed drive of an AC machine. The structure of MMC essentially requires energy balancing control so as to mitigate the voltage pulsation of each cell capacitor in converter arms. In the proposed control strategy, two operation modes are employed. One is a low frequency operation mode for start-up and low speed operation of the AC machine, and the other is a normal frequency operation mode from medium to rated speed of the AC machine. To reduce the pulsation, this paper proposes the energy balancing control strategies at each operation mode. Theoretically, the energy balancing control of the capacitors is prone to be unstable at low frequency operation. In order to prevent the instability, a special control strategy is introduced. The strategy exploits a common mode voltage and a circulating current with high frequency component in low frequency operation mode. With the proposed control scheme, the speed control range of the AC machine driven by MMC can be down to zero speed without instability of voltage of the cell capacitors. Experimental results for the energy balancing control are shown to demonstrate the effectiveness of the proposed control strategy.
KW - circulating currents
KW - modular multilevel converter
KW - power balancing control
KW - variable speed drives
UR - http://www.scopus.com/inward/record.url?scp=84876041177&partnerID=8YFLogxK
U2 - 10.1109/PEDES.2012.6484494
DO - 10.1109/PEDES.2012.6484494
M3 - Conference contribution
AN - SCOPUS:84876041177
SN - 9781467345088
T3 - PEDES 2012 - IEEE International Conference on Power Electronics, Drives and Energy Systems
BT - PEDES 2012 - IEEE International Conference on Power Electronics, Drives and Energy Systems
T2 - 2012 IEEE International Conference on Power Electronics, Drives and Energy Systems, PEDES 2012
Y2 - 16 December 2012 through 19 December 2012
ER -