2016 Volume 136 Issue 12 Pages 1015-1024
This paper provides a theoretical and experimental discussion on a modular multilevel triple-star bridge-cell (TSBC) converter with focus on mitigating the capacitor-voltage fluctuation contained in each bridge cell. This paper assumes that the TSBC converter drives an interior permanent magnet synchronous motor rated at 75Hz loaded at the rated torque. A new control method proposed in this paper is characterized by properly superimposing both common-mode voltage and circulating currents in the whole speed range from 0 to 75Hz. Moreover, this paper optimizes the amplitude and frequency of the superimposed common-mode voltage with the help of theoretical analysis, thus resulting in minimizing the voltage fluctuation. This optimized control method can reduce both the voltage fluctuation and the cluster-current amplitude to values below those of existing methods. Experimental waveforms obtained from a three-phase downscaled model verify good start-up performance from a standstill to the rated speed.
The transactions of the Institute of Electrical Engineers of Japan.C
The transactions of the Institute of Electrical Engineers of Japan.B
The transactions of the Institute of Electrical Engineers of Japan.A
The Journal of the Institute of Electrical Engineers of Japan