Features of Balancing a Three-Phase Step Voltage at the Output of Semiconductor Converters

The article discusses various ways to implement a discrete conversion of a constant voltage into a step three-phase variable using a semiconductor autonomous inverter. The harmonic composition analysis of the alternating step voltage obtained by discrete transformation is carried out. It is noted that such converters can be used as part of mini-hydroelectric power plants for organizing power supply to household consumers, when the requirements for the content of higher harmonics in the phase voltage do not exceed standard ones. It is shown that under implementing a discrete DC-to-AC step converter, it is relatively easy to solve the problems of balancing the voltage at the inverter output. This eliminates the need to use complex computational procedures with multiple transformation of voltages and currents from their phase values to vector values in a rotating coordinate system, and the balancing procedure is reduced to voltage regulation at the zero point of the three-phase load of the inverter relative to one of the buses of the DC voltage source. Such regulation is carried out by acting on the power switches of the additional fourth inverter rack, which is contained in all voltage balancing circuits. However, the algorithm for managing these keys is greatly simplified.