Medium-high-voltage frequency converter with multiple groups of inverter outputs

Abstract

The invention belongs to high-voltage frequency converter control techniques and provides a medium-high-voltage frequency converter with multiple groups of inverter outputs. The medium-high-voltage frequency converter with the multiple groups of inverter outputs comprises a rectifier transformer, secondary line windings of the rectifier transformer include three phases A, B and C, the secondary line winding of each phase is serially connected with at least one variable-frequency power unit, each variable-frequency power unit comprises an output end rectifying portion connected to the corresponding auxiliary line winding, and output ends of the rectifying portions are connected with a plurality of H-shaped single-phase inverter bridges through cascade busbars. The multiple H-shaped single-phase inverter bridges and the corresponding rectifying portions form single-input multi-H-bridge-inverter-output variable-frequency power units, and the multiple H-shaped single-phase inverter bridgesare in one-to-one correspondence to multiple motors or motors with multiple stator windings. The medium-high-voltage frequency converter has advantages that problems of torque (current) balance of multiple stator windings and speed uniformity of multiple motors in an operating process are solved, and integral equipment size and cost including operation and maintenance cost are reduced.

Description

technical field [0001] The invention belongs to the high-voltage frequency converter control technology and provides a medium-high voltage frequency converter with multiple sets of inverter outputs. Background technique [0002] Some mechanical equipment is usually driven by two or more medium and high voltage motors at the same time, or one medium and high voltage motor has multiple sets of stator windings. For example, heavy-duty rolling mills, large and medium-sized mine hoists include sinking hoists, large and medium-sized blast furnace hoists, ship lifts, large and medium-sized ventilators, large and medium-sized belt conveyors, roller presses, and so on. Traditional medium and high voltage inverters have only one set of inverter outputs. If it is necessary to drive two or more medium and high voltage motors with multiple sets of stator windings at the same time, one of the traditional methods ("one drive multiple") is to connect multiple sets of stator windings of t...

AI Technical Summary

Problems solved by technology

If it is necessary to drive two or more medium and high voltage motors with multiple sets of stator windings at the same time, one of the traditional methods ("one drive multiple") is to connect multiple sets of stator windings of the motor in parallel, and a medium and high voltage inverter Drive, which mainly has the following disadvantages: 1) The torque (current) of multiple motors or multiple sets of stator windings is not necessarily balanced; 2) The speed of each motor is not completely consistent when driving mechanical equipment connected by winding, such as a belt conveyor ; Not only affect the static and dynamic performance and efficiency of mechanical equipment, but also may lead to increased fatigue of the motor or mechanical equipment, thereby shortening the service life and increasing operation and maintenance costs

In the second traditional method ("one drive one"), one medium and high voltage frequency converter drives one motor or one set of stator windings, and the number of frequency converters is equal to the number of motors or the number of sets of stator windings; although master-slave control and other measures are adopted to solve The problem of torque (current) balance and speed consistency is solved, but the cost increases and the overall volume of the equipment increases, and the investment cost including equipment and its infrastructure is high

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