An Indirect Series Three-Phase Matrix Medium and High Voltage Frequency Converter

Abstract

The invention discloses an indirect series-connection three-phase matrix type medium-high voltage frequency converter. A step-down transformer T1 is provided with n auxiliary edges, and auxiliary windings are the same in phase and have no phase difference. A three phase-three phase matrix array A1-An is an array with one row and n lines, wherein the array is composed of n three phase-three phase matrix converter units. Each line of the array is correspondingly connected with the corresponding set of auxiliary edges of the step-down transformer. All phases of output of each three phase-three phase matrix are coupled and connected together in series through an isolation transformer, and therefore alternating-current three-phase output is formed. A controller is responsible for controlling and adjusting work of the whole system. By means of the indirect series-connection three-phase matrix type medium-high voltage frequency converter, low-voltage low-power three phase-three phase matrix converters or three phase-three phase matrix converters composed of high-voltage IGBTs can be coupled and connected in series through the isolation transformer to form a high-voltage power supply with the adjustable amplitude and the adjustable frequency, the output voltage and the input current are both sine waves, the input power coefficient is close to one, and energy can flow in two directions, and the indirect series-connection three-phase matrix type medium-high voltage frequency converter has the advantage of having the four-quadrant operation capacity and is suitable for the field of medium-high voltage alternating-current motor transmission.

Description

technical field [0001] The invention relates to a frequency converter, in particular to an indirect series three-phase matrix medium-high voltage frequency converter, which belongs to the technical field of power electronic equipment. Background technique [0002] In the field of medium and high voltage high-power AC power transmission, the currently applied power electronic converter solutions mainly include: 1. AC-DC-AC high-voltage inverter with power switches or power units directly connected in series; 2. Three-level AC-DC-AC inverter clamped by diodes 3. Two-level current type AC-DC inverter. However, in practical applications, these three types of medium and high voltage inverters inevitably have defects: Type 1 inverters have a large number of power devices, huge equipment, and difficulty in bidirectional energy flow; Type 2 inverters have large harmonics and low power factor , Low efficiency; Type 3 frequency converter du / dt has a large impact, a large impact on ha...

AI Technical Summary

Problems solved by technology

However, in practical applications, these three types of medium and high voltage inverters inevitably have defects: Type 1 inverters have a large number of power devices, huge equipment, and difficulty in bidirectional energy flow; Type 2 inverters have large harmonics and low power factor , low efficiency; Class 3 inverters have large du / dt impact, large harmonic and reactive power effects, and great influence on motor insulation

The medium and high voltage inverters that can meet the above conditions are high-voltage-low-voltage-high-voltage cascaded multiple AC inverters, and the indirect series three-phase matrix medium and high voltage inverters are one of them. At present, there is no public report on related technologies

Images