Selection of parameters for balancing circuit of DC-DC and AC-AC multicell converters

The paper presents a dc/dc and ac/ac multicell converters with balancing circuit. The multicell converters use voltage sources of different values placed in every cell. Low capacitance capacitors may be used as the cells´ sources. But in that case an improper proportion of the source capacitors voltages can occur, which is very dangerous in multilevel converters. To eliminate this voltage unbalance the RLC series circuit (balancing circuit) is connected to load in parallel. Phenomenon of stabilization of voltages on cells´ capacitors by balancing current, mathematical description of the converter, energy transfer from source under unbalance state, sensibility of the system for balancing circuit parameters variation is presented. For three-cell dc/dc converter dynamical states and power losses in steady state versus parameters of the balancing circuit are analyzed. In ac/ac multicell converter the balancing circuit parameters determines the converter´s steady state. For three-cell ac/ac converter all quantities of the system that affect the proper proportion of cells´ voltages are presented