LOW-FREQUENCY FREQUENCY CONVERTER DRIVEN BY NETWORK Russian patent published in 2012 - IPC H02M5/16 

FIELD: electricity.

SUBSTANCE: invention relates to electrical equipment and is designed for use in an electric drive for control of speed of induction motors. Each of three semiconductor modules is connected to a three-phase AC network. Semiconductor transistors are used in each of three semiconductor modules. In the first semiconductor module collectors of the first, second and third transistors are combined and connected with a common point to the start of the first winding of the three-phase induction motor, emitters of the first, second and third transistors are connected to appropriate windings of the three-phase transformer. In the second semiconductor module collectors of the fourth, fifth and sixth transistors are combined and connected to the start of the second winding of the three-phase induction motor, emitters of the fourth, fifth and sixth transistors are connected to appropriate windings of the three-phase transformer. In the third semiconductor module collectors of the seventh, eighth and ninth transistors are combined and connected to the start of the third winding of the three-phase induction motor, emitters of the seventh, eighth and ninth transistors are connected to appropriate windings of the three-phase transformer. Ends of the first, second and third windings of the three-phase induction motor are combined and connected to zero of the transformer.

EFFECT: higher reliability, reduced dimensions, and also simplified control system due to reduced number of switching semiconductor equipment.

3 dwg