Analytical and simulation comparison of sinusoidal and resistive modulation strategies for network-friendly three-phase grid-connected inverters

The growing numbers of consumers distort AC networks with harmonics. Therefore suppression of the network pollution should be considered. This problem can be solved by using "network-friendly" converters. In our study we examined two modulation strategies of three-phase grid-connected inverters. If these methods are used, converters behave like sinusoidal or resistive current loads of the network, which enables "network-friendly" operation. The examined sinusoidal and the resistive modulation strategies are known, but the differences between the two methods have not been studied before [1,2]. This paper deals with the comparison of these two strategies. First, the analytical examination is presented By comparing their consumed RMS currents we defined a coefficient (k[%]), which depends only on the total harmonic distortion of the network voltage (THD(U)). We demonstrated that at high THD(U) resistive modulation method is more favorable. Then simulation examination is discussed, by presenting our model of the three-phase four quadrant converter. Finally simulation results are represented in this article.