1000KW/1140V mining explosion-proof twelve-pulse power supply frequency conversion device

Abstract

The invention relates to a 1000KW / 1140V mining explosion-proof twelve-pulse power supply frequency conversion device comprising a filter unit, a rectifier unit, an inverter unit and an auxiliary circuit. The filter unit comprises an input filter unit and an intermediate filter unit, wherein the input filter unit is a line reactor; and the intermediate filter unit is a capacitor filter unit. The rectifier unit is a six-pulse rectifier bridge. The inverter unit is an IGBT (insulated gate bipolar transistor) inverter module. Two groups of 1140V and 50Hz three-phase alternating-current supplies with phase difference of 30 degrees are respectively rectified to direct current by a path of circuit connected by the line reactor, an isolating switch, a vacuum contactor and the six-pulse rectifier bridge, and two paths of the direct current are connected in parallel and are inverted to the alternating current with adjustable frequency by the intermediate filter unit and the IGBT inverter module. A main circuit of the invention adopts an alternating-direct-alternating voltage source transducer structure and adopts a twelve-pulse rectifier mode, therefore, a smooth direct current voltage can be obtained, impact on a power grid by harmonic wave is greatly reduced, the power grid environment is purified, and the consumption of the reactive current is controlled at the same time.

Description

technical field [0001] The invention relates to a 12-pulse power supply frequency conversion device, in particular to a mining explosion-proof and intrinsically safe AC frequency converter with a voltage level of 1140V and a power of 1000kW. Background technique [0002] In recent years, my country has done a lot of research work on explosion-proof motors, such as increasing the voltage level and power of the motor. At present, the demand for explosion-proof motors above 500kW is increasing day by day, and it is imminent to solve the problem of speed regulation of high-power explosion-proof motors used in mines. At present, the high-power explosion-proof frequency conversion speed control device mainly has the following deficiencies: [0003] 1. Harmonic problem. This is a problem that most frequency converters currently have, especially in high-power frequency conversion speed regulation. The output voltage of the frequency converter contains other harmonics except the f...

AI Technical Summary

Problems solved by technology

Lower harmonics usually have a greater impact on the motor load, causing torque ripple, while higher harmonics increase the leakage current of the inverter output cable, resulting in insufficient motor output

Harmonics will pollute the power grid, affect other electrical equipment on the same power grid, and even affect the normal operation of the power system; Increase the loss of the motor, thus increasing the heat, reducing the efficiency and power factor, so that it has to be used with "derating"

[0004] 2. Reactor heating problem

Severe heating of the reactor will increase the temperature in the inverter cavity. When other devices work in a high temperature environment for a long time, the service life will be reduced, and even the device will be damaged.

[0005] 3. The inverter capacity is limited

The maximum capacity of 1140V mining frequency converter can reach 630kW, which cannot meet the needs of high-power coal mining equipment to increase capacity

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