R.Arun kumar, S.Sankarananth, V.RaviKumar, T.Bharani Prakash
Abstract: This paper presents the comparison between improved asymmetric space vector modulation (ASVM) and sinusoidal pulse width modulation (SPWM) for voltage source converters (VSCs) when the switching frequency is as low as 9 times of line frequency. By enumerating two pulses in every line cycle at the time of fundamental voltage reaches zero, the total harmonic distortion (THD) of output current can be condensed considerably. In high power factor operating areas the forfeit of reckoning switching loss is very circumscribed. The improved asymmetric vector modulation application in a single voltage source converter is shown. With the optimization of the duration and position of the additional pulses, the THD of ac current can be condensed to as below as 25 % for single VSC. Such THD reduction has precise affiliation with space vectors position and modulation index. Amplitude of the circulating current can also be condensed by improved ASVM, governing to smaller inter-phase inductors. The examination outcomes are confirmed by experiments on a demo system.
Keywords: Voltage Source Converter VSC, Total Harmonic Distortion THD, Asymmetric Space Vector Modulation ASVM