Artículos de revistas
A modular multilevel series/parallel converter for a wide frequency range operation
Registro en:
IEEE Transactions on Power Electronics, Volume 34, Issue 10, October 2019, pages: 9854-9865
Autor
Li, Zhongxi
Lizana F., Ricardo
Yu, Zhujun
Sha, Sha
Peterchev, Angel V.
Goetz, Stefan M.
Resumen
Artículo de publicación scopus When providing ac output, modular multilevel converters (MMCs) experience power fluctuation in the phase arms. The power fluctuation causes voltage ripple on the module capacitors, which grows with the output power and inversely to the output frequency. Thus, low-frequency operations of MMCs, e.g., for motor drives, require injecting common-mode voltages and circulating currents, and strict dc voltage output relative to ground is impossible. To address this problem, this paper introduces a novel module topology that allows parallel module connectivity in addition to the series and bypass states. The parallel state directly transfers power across the modules and arms to cancel the power fluctuations and hence suppresses the capacitor voltage ripple. The proposed series/parallel converter can operate at a wide frequency range down to dc without common-mode voltages or circulating currents; it also allows sensorless operation and full utilization of the components at higher output frequencies. We present detailed simulation and experiment results to characterize the advantages and limitations of the proposed solution.