CN112260978A

CN112260978A - Communication method between active unbalance compensation devices

Info

Publication number: CN112260978A
Application number: CN202011157751.6A
Authority: CN
Inventors: 范建华; 曹乾磊; 马鲁宁
Original assignee: Qingdao Topscomm Communication Co Ltd
Current assignee: Qingdao Topscomm Communication Co Ltd
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-01-22

Abstract

The invention discloses a communication method between active unbalance compensation devices, which comprises the following steps: step 1, an Active Unbalance compensation device (AUC) sends a signal instruction, the instruction is modulated by a PWM (pulse width modulation) modulator in the device before being sent, and on the premise of ensuring the original electric power function, the corresponding ripple waves are generated in a circuit by utilizing the switching between two carriers with different frequencies; step 2, amplifying the signals by the communication receiving ends of other AUC devices through an operational amplifier circuit; step 3, a band-pass filter in the communication receiving circuit filters the characteristic signal; and 4, reading and analyzing the signal by the communication receiving circuit. The invention solves the problem that AUC devices can not communicate with each other, thereby utilizing the capacity of the AUC devices arranged on different branches of the power line to the maximum extent and reducing the overall three-phase unbalance degree of the power line.

Description

Communication method between active unbalance compensation devices

Technical Field

The invention relates to the technical field of power communication, in particular to a communication method between active unbalance compensation devices.

Background

With the development of power electronic technology and the emergence of various electric devices, the operating environment of a power grid becomes more and more complex, and the condition of three-phase imbalance of the power grid is caused by different loads and element parameters of each phase of the power grid, so that the problems of increased line loss of the power grid, reduced motor efficiency and the like are caused. An Active Unbalance Compensator (AUC) compensates a fundamental Unbalance current (a negative sequence current or a zero sequence current) of a load by using a power electronic converter technology to eliminate or reduce a three-phase current Unbalance degree in a power grid.

At present, the AUC of each branch is mainly used for governing the three-phase unbalance degree of the branch where the branch is currently located, and is influenced by different loads of each phase of a line, the capacity of some branch AUC devices cannot compensate the current line, while some branch AUC devices may be in a capacity residual state, the capacity of each AUC device cannot be fully utilized, and if the AUC devices can communicate with each other, the overall three-phase unbalance degree of a power grid can be greatly reduced.

Disclosure of Invention

Aiming at the defects and shortcomings of the prior art, the invention provides a communication method between active unbalance compensation devices, which solves the problem that AUC devices cannot communicate with each other, thereby utilizing the capacity of AUC of each branch to the maximum extent and reducing the overall three-phase unbalance of a power grid line.

The purpose of the invention can be realized by the following technical scheme:

a method of communication between active imbalance compensation devices, comprising the steps of:

step 1: the AUC device sends a signal instruction, the instruction is modulated by a PWM (pulse-width modulation) modulator in the device before being sent, and corresponding ripples are generated in a circuit by utilizing the switching between two carriers with different frequencies on the premise of ensuring the original electric power function, so that the combination of instruction information and an electric signal is realized;

step 2: the communication receiving ends of other AUC devices amplify the signals through the operational amplifier circuit;

and step 3: a band-pass filter circuit in the communication receiving circuit filters interference signals;

and 4, step 4: the communication receiving circuit reads the analytic signal.

Further, the two different carrier frequencies in step 1 are 10kHz and 20kHz, respectively.

Further, the signal modulation method used by the PWM modulator in step 1 is 2 FSK.

Further, the 2FSK method used by the PWM modulator is applied in the present invention in the following manner: when transmitting '0' signal, transmitting carrier wave with frequency of 10 kHz; when transmitting the '1' signal, a carrier wave with the frequency of 20kHz is transmitted.

Further, the signal analysis method in step 4 is Discrete Fourier Transform (DFT).

Further, any AUC device in the above scheme may serve as both a signal transmitting end and a signal receiving end.

The invention has the beneficial technical effects that: the method comprises the steps of modulating command signals through an AUC device and a PWM/2FSK technology, transmitting the signals into a power grid, receiving the signals by other AUC devices connected with the same power line, amplifying the signals through an operational amplifier circuit, filtering and extracting specific signals through a band-pass filter, and finally analyzing information in the signals through a discrete Fourier transform method, so that the problem of communication among the AUC devices is solved, and the overall three-phase unbalance degree of a line in the power grid is reduced.

Drawings

Fig. 1 is a communication flow diagram of the present invention.

Fig. 2 is a result of the signal transmission AUC device according to the embodiment of the present invention for line three-phase imbalance management.

Fig. 3 shows a voltage waveform and a frequency spectrum of a signal transmitted from the AUC device to the power line at the point of connection according to the embodiment of the present invention.

Fig. 4 shows a voltage waveform and a frequency spectrum of a signal received by the signal receiving AUC device according to the embodiment of the present invention after being processed by the operational amplifier circuit.

Fig. 5 shows a current waveform and a frequency spectrum of a signal received by the signal receiving AUC device according to the embodiment of the present invention after being processed by a band-pass filter.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and do not limit the invention.

As shown in fig. 1, in the method, any AUC device transmits a signal to another AUC device connected to the AUC device through a power line, and after the other devices receive the signal transmitted from the power line, the current signal is processed through an operational amplifier circuit and a band-pass filter, and finally the signal transmitted by the AUC device is obtained through analysis, and the implementation steps are as follows:

step 1: before the instruction is sent, the PWM modulator in the AUC device modulates the signal by a 2FSK method, as can be seen from figures 2 and 3, on the premise of ensuring the original electric power function, the device generates a corresponding ripple wave in a circuit by switching between carrier waves with two different frequencies of 10kHz and 20kHz, and the signal sent by the embodiment is 111000011000110011 (when a '0' signal is set, the carrier wave with the frequency of 10kHz is sent; when a '1' signal is transmitted, the carrier wave with the frequency of 20kHz is sent);

step 2: the communication receiving ends of other AUC devices amplify the signals through the operational amplifier circuit, and as can be seen from fig. 4, the signals are amplified by 10 times;

and step 3: a band-pass filter circuit in the communication receiving circuit filters signals;

and 4, step 4: the communication reception circuit analyzes the signal by the discrete fourier transform method, and receives the signal 111000011000110011, as shown in fig. 5.

The above-mentioned embodiments are illustrative of the specific embodiments of the present invention, and are not restrictive, and those skilled in the relevant art can make various changes and modifications to obtain corresponding equivalent technical solutions without departing from the spirit and scope of the present invention, so that all equivalent technical solutions should be included in the scope of the present invention.

Claims

1. A method of communicating between active imbalance compensation devices, comprising the steps of:

step 1: an Active Unbalance Compensator (AUC) sends a signal instruction, the instruction is modulated by a PWM (pulse-width modulation) modulator in the device before being sent, and on the premise of ensuring the original electric power function of the device, the corresponding ripple waves are generated in a circuit by utilizing the switching between two carrier waves with different frequencies;

and step 3: a band-pass filter circuit in the communication receiving circuit filters other signals except the characteristic signal;

and 4, step 4: the communication receiving circuit reads the analytic signal.

2. The method as claimed in claim 1, wherein the two different carrier frequencies in step 1 are 10kHz and 20kHz, respectively.

3. The communication method according to claim 1, wherein the signal modulation method used by the PWM modulator in step 1 is 2 FSK.

4. The communication method between active imbalance compensation devices according to claim 3, wherein the 2FSK method used by the PWM modulator is applied in the following manner: when transmitting '0' signal, transmitting carrier wave with frequency of 10 kHz; when transmitting the '1' signal, a carrier wave with the frequency of 20kHz is transmitted.

5. The method of claim 1, wherein the signal analysis method in step 4 is Discrete Fourier Transform (DFT).

6. The method according to claim 1, wherein any AUC device in the scheme can be used as both a signal transmitting end and a signal receiving end.