CN201328068Y - Mineral flame-proof type transducer electromagnetic compatibility system - Google Patents

Abstract

The utility model discloses a mineral flame-proof type transducer electromagnetic compatibility system. An isolating switch induces a three-phase AC power into a flame-proof cavity; the isolating switch is connected with an input reactor through a lead; the input reactor is connected with an input filter through a lead; the input filter is connected with a transducer through a lead; the transducer is connected with an output reactor through a lead; the output reactor is connected with an output filter through a lead; the isolating switch is connected with an ultraharmonics automatic monitor through a lead; the ultraharmonics automatic monitor is connected with an intelligent comprehensive protector through a lead; the intelligent comprehensive protector is connected with the transducer through a lead; and the output filter is connected with the ultraharmonics automatic monitor through a lead. An electromagnetic compatibility device and the transducer are arranged in the same flame-proof cavity; the flame-proof cavity is used as the electromagnetic shield of the transducer and the electromagnetic compatibility device to reduce the outward radiation disturbance of the transducer and the electromagnetic compatibility device; in addition, the shortest connection line is ensured between the electromagnetic compatibility device and the transducer, so as to have the better filter effect.

Description

Mine Flameproof Frequency Converter Electromagnetic Compatibility System

technical field

The utility model belongs to an electromagnetic compatibility scheme of a mine flameproof frequency converter, in particular to an electromagnetic compatibility system using a high-order harmonic automatic monitor and an intelligent comprehensive protector.

Background technique

At present, in the field of coal mines, the application of frequency converters has begun to be popularized, but the electromagnetic interference caused by the application of frequency converters cannot be ignored. The frequency converter is a nonlinear load to the power grid, and it outputs high-order harmonic current to the power grid, causing voltage distortion and current distortion of the power grid, causing electromagnetic pollution, and affecting the normal operation of other electronic and electrical equipment on the power grid; the high-order harmonic current output by the frequency converter to the power grid is also There is a danger of causing circuit resonance. The output of the inverter is a sinusoidal pulse width modulated SPWM wave voltage, which is a rectangular wave with equal height and different width, which contains rich high-order harmonics, which will increase the loss of the motor operation, increase the additional torque of harmonics, vibration, overheating and reduce Effort and other influences. The capacity of underground mobile substations in coal mines is relatively small. Even if a small frequency converter is used in the system, the voltage distortion THDv is still 10%-40%. Many important electronic and electrical equipment are used in underground coal mines. These electronic and electrical equipment generally contain CPU chips. and program software are extremely susceptible to electromagnetic interference and cannot work normally. Therefore, it is very necessary to add electromagnetic compatibility to the mining frequency converter.

Contents of the invention

The purpose of the utility model is to provide a mining explosion-proof frequency converter electromagnetic compatibility system with good electromagnetic compatibility and strong anti-electromagnetic interference capability.

In order to achieve the above purpose, the solution of the utility model is: a mining explosion-proof inverter electromagnetic compatibility system, which consists of an explosion-proof cavity, an isolating switch, an input reactor, an input filter, a frequency converter, an output filter, an output Reactor, high-order harmonic automatic monitor, and intelligent comprehensive protector. The isolating switch introduces the three-phase AC power into the explosion-proof cavity. The isolating switch is connected to the input reactor through a wire, and the input reactor passes The wire is connected to the input filter, the input filter is connected to the frequency converter through the wire, the frequency converter is connected to the output reactor through the wire, the output reactor is connected to the output filter through the wire, and the isolation switch is connected to the inverter through the wire Connect with the high-order harmonic automatic monitor, the high-order harmonic automatic monitor is connected to the intelligent comprehensive protector through the wire, the intelligent comprehensive protector is connected to the frequency converter through the wire, and the output filter is connected through the wire Connect with high harmonic automatic monitor.

The electromagnetic compatibility device and the frequency converter are installed in the same explosion-proof chamber, and the explosion-proof chamber serves as the electromagnetic shielding body of the frequency converter and the electromagnetic compatibility device, reducing the external auxiliary radiation interference of the frequency converter and the electromagnetic compatibility device; and making the electromagnetic compatibility device and the electromagnetic compatibility device The frequency converter has the shortest connection, which makes the filtering effect better. In order to finally eliminate the serious electromagnetic interference of the inverter on other important electronic and electrical equipment and avoid accidents, the device is equipped with an automatic high-order harmonic monitor and an intelligent comprehensive protector. By detecting the three-phase current and three-phase voltage of the power grid in real time, The discrete Fourier transform sliding window iterative harmonic detection algorithm calculates the harmonic content of current and voltage in real time. When the electromagnetic interference of the inverter to other important electronic and electrical equipment reaches an intolerable level, the inverter will stop running.

Description of drawings

Fig. 1 is a schematic structural view of an embodiment of the utility model.

Detailed ways

As shown in Figure 1, the isolating switch 1 introduces the three-phase AC power into the explosion-proof cavity, the isolating switch 1 is connected with the input reactor 2 through the wire, and the input reactor 2 is connected with the input filter 3 through the wire, the The input filter 3 is connected to the frequency converter 4 through wires, the frequency converter 4 is connected to the output reactor 5 through wires, and the output reactor 5 is connected to the output filter 6 through wires. The isolating switch 1 is connected to the high-order harmonic automatic monitor 7 through a wire, and the high-order harmonic automatic monitor 7 is connected to the intelligent comprehensive protector 8 through a wire, and the intelligent comprehensive protector 8 is connected to the intelligent comprehensive protector 8 through a wire. Inverter 4 is connected. The output filter 6 is connected with a higher harmonic automatic monitor 7 through wires.

The utility model is composed of a main circuit and a protection circuit, wherein the isolation switch 1, the input reactor 2, the input filter 3, the frequency converter 4, the output reactor 5, and the output filter 6 constitute the main circuit, and the high-order harmonic automatic monitor 7. The intelligent integrated protector 8 constitutes a detection and protection circuit, and the input reactor 2 is connected to the input filter 3 through wires to form an input filtering part, which is used to reduce the interference of the frequency converter to the power grid and the power grid to the frequency converter. It has the effect of weakening the input surge. The output reactor 5 is connected with the output filter 6 through wires to form an output filter part, which is used to reduce the interference of the frequency converter to the motor, and at the same time has the effect of weakening electromagnetic radiation. The isolating switch 1 is connected with the high-order harmonic automatic monitor 7 through a wire, and is used for sampling the harmonic signal at the input end. The output filter 6 is connected to the high-order harmonic automatic monitor 7 through a wire, and is used for sampling the harmonic signal at the output end. The harmonic signal is processed and calculated by the high-order harmonic automatic monitor and the intelligent comprehensive protector. When the electromagnetic interference reaches an intolerable level, the inverter will stop running to achieve the purpose of protecting the circuit safety.

The filtering function of the input reactor 2 and the input filter 3 is bidirectional, namely reducing the energy of the high-order harmonic signal transmitted by the frequency converter to the grid, and reducing the energy of the high-order harmonic signal transmitted by the grid to the frequency converter. The filtering function of the output reactor 5 and the output filter 6 reduces the energy of the high-order harmonic signal output from the frequency converter to the motor. The high-order harmonic automatic monitor 7 monitors the voltage and current harmonic content of the input and output sides of the inverter in real time. The allowable value of each harmonic content can be set by software. When the voltage and current high-order harmonics at the monitoring point exceed the specified The limit value will send a signal to make the intelligent comprehensive protector 8 act, and the frequency converter can protect and trip.

Claims (1)

1. A mining explosion-proof frequency converter electromagnetic compatibility system, consisting of a flameproof cavity, an isolating switch, an input reactor, an input filter, a frequency converter, an output filter, an output reactor, an automatic high-order harmonic monitor, Composed of an intelligent comprehensive protector, it is characterized in that: the isolating switch (1) introduces the three-phase AC power into the explosion-proof cavity, the isolating switch (1) is connected to the input reactor (2) through a wire, and the input reactance The converter (2) is connected to the input filter (3) through the wire, the input filter (3) is connected to the frequency converter (4) through the wire, and the frequency converter (4) is connected to the output reactor (5) through the wire , the output reactor (5) is connected to the output filter (6) through a wire, and the isolating switch (1) is connected to a high-order harmonic automatic monitor (7) through a wire, and the high-order harmonic automatic monitoring The device (7) is connected to the intelligent comprehensive protector (8) through the wire, the intelligent comprehensive protector (8) is connected to the frequency converter (4) through the wire, and the output filter (6) is connected to the high-order The harmonic automatic monitor (7) is connected.

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