Problems Solving of Power Elements Uniform Loading and Energy Losses Reducing in a Multilevel Converter Based on a Universal Source of Levels

The paper presents study results of energy circulation and accumulation in the process of the output voltage curve forming in a single-phase multilevel inverter based on a universal two-channel source of levels, the power circuit structure of which does not depend on the number of levels. Objective of the study is developing of methods for active losses reducing in circuits for recharging of the pulse converters output capacitors, as well as in the process of reactive power exchange between the load and the source of levels. Measures to ensure uniform loading of the corresponding power semiconductor elements of the converter in the process of the output voltage curve forming are considered. It is shown that the reduction of energy losses is achieved by adding to circuits of pulse converters circuits for resetting of inductances excess currents to the power supply source of the multilevel inverter. It is proved that the decrease of the uneven loading of power semiconductor elements is achieved with the proposed asymmetric distribution of curve generated levels between pulse converters, as well as with an increase in the number of levels.