About the Features of Structural Parametric Synthesis of Single-Phase Voltage Source Inverters with Multi-Channel Conversion of the Energy Flow

摘要

In the development of high-power voltage source inverter (by order of MW and more), when unit power of available key elements is insufficient for their practical implementation, the principle of multi-channel conversion (MCC) of energy flow is used. Its essence is to divide energy flow into M parts, in corresponding conversion of these parts and their subsequent summation of output circuit. This paper considers class of VSI with MCC when currents-summation of channels by using transfilters(TFs). A distinctive feature of their synthesis is use of same structure N-level inverter cells in channels, parameters of output voltage of which are optimized for minimum total harmonic distortion – THD. This class of SPVSI is designated as M•N-SPVSI. The shape of their resulting output voltage has form of signal with pulse-amplitude modulation (PAM), with values of its M•Nnumber of levels for a quarter of output frequency period are close (with an accuracy of about 3%) to corresponding values, which are optimized for minimum THD(V).A regularity has been established: with increasing values of M and N, the value of the parameter THD(V) decreases, which allow to reduce mass of filtering tools. Examples of the synthesis of М•N- SPVSI at N = 2,3 and M = 4 are given. The features of the SPVSI structures in this class should also include the presence of two TFs, each of which is configured to magnetically symmetrical rod M-magnetic core. And method for calculating the overall power of TFs is proposed. The results of solving the problem of minimizing this indicator due to the rational parametric synthesis of voltage form in the channels are presented. The tasks were solved on the basis of computer simulation in the OrCAD PSpice Schematics.