THREE-LEVEL FREQUENCY CONVERTER Russian patent published in 2018 - IPC H02M5/453 

FIELD: electrical engineering.

SUBSTANCE: invention relates to the field of electrical engineering and power electronics, in particular to static frequency converters with double conversion of electrical energy. Purpose of the invention is to use a transformerless power circuit of a three-level frequency converter, and also a fixed uniform distribution of the DC link voltage. Proposed device of the three-level frequency converter allows to exclude from the power channel a multi-winding transformer designed for the full power of the frequency converter, and also to exclude from the circuit one three-phase full-wave voltage rectifier. Advantage of the proposed three-level frequency converter is the simplicity of the circuit implementation, reliability, and also the possibility of regulating the voltage of the three-level voltage rectifier both downward and upward from the voltage determined by the uncontrolled rectifier. Use of a multiphase AC source will significantly reduce the level of voltage ripple in the DC link. Set goals are achieved by adding a new connection to the three-level frequency converter circuit between the zero terminal of the three-phase alternating voltage source and the zero bus of the DC link of the three-level frequency converter.

EFFECT: technical result of the proposal is to reduce weight, dimensions and cost, as well as improve the functionality of the frequency converter and increase the reliability of its operation.

5 cl, 6 dwg