Single-input and multi-inverter-bridge-output low-voltage frequency converter

Abstract

The invention belongs to a low-voltage frequency converter control technology and provides a single-input and multi-inverter-bridge-output low-voltage frequency converter. The single-input and multi-inverter-bridge-output low-voltage frequency converter provided by the invention is provided with a plurality of groups of three-phase inverter bridges which correspond to the set number of needed driving motors or the set number of motor stator windings one by one; input ends of the plurality of groups of three-phase inverter bridges are connected with an output end of a three-phase rectifying bridge; three-phase output of the plurality of groups of three-phase inverter bridges is connected with the corresponding motors or the motor stator windings respectively to form a two-quadrant low-voltage frequency converter or a four-quadrant low-voltage frequency converter; triggering devices of the plurality of groups of three-phase inverter bridges are connected with an inverter bridge controller. According to the single-input and multi-inverter-bridge-output low-voltage frequency converter provided by the invention, the aim of simultaneously controlling a plurality of sets of low-voltage motors or a low-voltage motor provided with the plurality of sets of motor stator windings in the same mechanical equipment is realized; the requirement of driving mechanical smooth speed regulation oftwo sets and more than two sets of the low-voltage motors or the low-voltage motor provided with the plurality of sets of motor stator windings is met.

Description

technical field [0001] The invention belongs to the low-voltage frequency converter control technology, and proposes a low-voltage frequency converter with single input and multiple inverter bridge outputs. Background technique [0002] Some mechanical equipment is usually driven by two or more low-voltage motors at the same time, or a low-voltage motor has multiple sets of stator windings. For example, light rolling mills, small and medium-sized mine hoists, small and medium-sized blast furnace hoists, axial fans, small and medium-sized belt conveyors, etc. Traditional low-voltage inverters have only one inverter bridge output. If it is necessary to drive two or more low-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 together and drive them by a low-voltage frequency converter. , which mainly has the following disadvantages: 1) The to...

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Problems solved by technology

If it is necessary to drive two or more low-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 together and drive them by a low-voltage frequency converter. , 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 the driving mechanical equipment connected by winding, such as a belt conveyor, is not exactly the same between the motors; It not only affects 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 low-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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