MODELING, SIMULATION AND CONTROL OF THE ALTERNATE ARM CONVERTER

Abstract

The The Modular Multilevel Converter has been one of the frontrunner in the emerging topology of VSC implemented in High Voltage Direct Current applications for a decade because of its innumerable advantages like excellent performance, reduced level of harmonics in the converter output without the necessity of filters, controllability, scalability, high power handling and high voltage capability and the foremost application in HVDC, the DC fault blocking capability and so on. A new hybrid topology of MMC called the Alternate arm converter which is designed with the combination of MMC and a two level converter possessing the ability to generate higher AC output voltage than the DC input voltage at a critical point of the converter called the sweet spot where the energy transfer between the AC and DC side of the converter is achieved is discussed in this paper. The reduction in the number of switching devices is achieved in AAC due to the alternate conduction of the director switches (two level converter) in the arms leading to a significant reduction in power loss. This paper presents a review on the operation principles and theoretical analyses of the Alternate Arm Converter (AAC). The mathematical model of the AAC has been designed and simulated with the help of Matlab for three phase Converter. The THD for the reduced model of AAC was also calculated and analyzed.