Topology circuit for mining frequency converter

Abstract

The invention discloses a topology circuit for a mining frequency converter. The topology circuit comprises a series reactor, a grounding coupling circuit, a pre-charging circuit and a power unit, wherein the output end of the series reactor is connected with the input ends of the grounding coupling circuit and the pre-charging circuit respectively; the output end of the pre-charging circuit is connected with the input end of the power unit; the output ends of the grounding coupling circuit and the power unit are connected with the input end of a motor at the same time. The topology circuit is simple in structure; through the series reactor, the grounding coupling circuit and the pre-charging circuit, the frequency converter can be effectively prevented from releasing harmonic waves into a power grid, and impact on a rectification unit at the moment of electrification is further eliminated; through the grounding coupling circuit, the common-mode voltage can be better eliminated, and the electromagnetic interference is eliminated.

Description

technical field [0001] The invention relates to a frequency converter topological circuit, in particular to a mining frequency converter topological circuit. Background technique [0002] With the wide application of 1140V voltage in the coal industry, 1140V inverters are also produced along with the coal market. The topological structure of mining inverters is mostly composed of three-phase diode rectifier units, DC capacitors, discharge resistors, and insulated gate bipolar transistors. (IGBT) bridge composition, such as patent 1: application number: 201120444090.5 "1140V / 600V dual-voltage inverter for mining" such as figure 1 As shown, a 1140V / 600V mining dual-voltage inverter includes a rectifier unit, a DC circuit, and an inverter circuit. The input voltage is directly connected to the three-phase diode rectifier unit. Stable, directly connected to the motor through the inverter unit composed of IGBT bridge. The main circuit of the mine-used dual-voltage frequency...

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Problems solved by technology

[0004] However, the above-mentioned existing technologies all have the following disadvantages: first, the AC power is directly connected to the rectifier unit, and the rectifier unit is easily damaged when the power is turned on instantaneously; Due to the large impact, directly driving the motor after the inverter output is likely to generate high common-mode voltage, generate electromagnetic interference, and easily damage the motor

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