Variable frequency power unit with single input and multi-H bridge inversion outputs

Abstract

The invention belongs to the technology of high voltage inverter control, and provides a variable frequency power unit with single input and multi-H bridge inversion outputs, wherein three groups of variable frequency power units with single input and multi-H bridge inversion outputs are arranged corresponding to the three-phase output of a rectifier transformer; at least one variable frequency power unit is arranged in each group; each variable frequency power unit has a rectification part connected to the output terminal of a secondary line winding of the rectifier transformer; the output terminal of the rectification part is connected with multiple H-shaped single-phase inverter bridges by a laminated busbar; the multiple H-shaped single-phase inverter bridges are in one-to-one correspondence with the quantity of motors or quantity of motor stator windings needing to be driven by the frequency converter; IGBT triggers of the multiple H-shaped single-phase inverter bridges are all connected with a same power unit controller, and one power unit controller controls the multiple H-shaped single-phase inverter bridges at the same time, so that the multiple H-shaped single-phase inverter bridges output synchronously. According to the invention, the aim of controlling multiple medium and high voltage motors or a medium and high motor with multiples sets of stator windings in same mechanical equipment is achieved, and the requirements of smooth speed regulation of driving machinery for two or more medium and high voltage motors or a medium or high voltage motor with multiple sets of stator windings are met.

Description

technical field [0001] The invention belongs to the control technology of a high-voltage frequency converter, and proposes a frequency conversion power unit with single input and multiple H bridge 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. The traditional variable frequency power unit has only one inverter bridge output, and the medium and high voltage inverter composed of this has only one set of inverter outputs. If you want to drive two or more medium and high voltage motors with multiple sets of stator windings at the same time, on...

AI Technical Summary

Problems solved by technology

If you want 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 the stator windings of multiple medium and high voltage motors in parallel, and one medium and high voltage frequency conversion This 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 between the motors is not complete when driving mechanical equipment connected by winding, such as belt conveyors. Consistent; 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"), a medium and high voltage frequency converter drives a motor or a set of stator windings, and the number of frequency converters is equal to the number of sets (sets) of motors or stator windings; although master-slave control, etc. Measures solve the problem of torque (current) balance and speed consistency, 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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