CN204882712U

CN204882712U - Electric wire netting harmonic electric energy measuring device based on DSP

Info

Publication number: CN204882712U
Application number: CN201520645721.8U
Authority: CN
Inventors: 王立伟
Original assignee: Individual
Current assignee: Individual
Priority date: 2015-08-25
Filing date: 2015-08-25
Publication date: 2015-12-16
Anticipated expiration: 2025-08-25

Abstract

The utility model relates to an electric wire netting harmonic electric energy measuring device based on DSP, its key feature is: including switching power supply module, signal acquisition module, signal processing module and man -machine interface module, switching power supply module is connected and is its power supply with signal acquisition module, signal processing module and man -machine interface module, signal acquisition module output signal delivers to signal processing module, and signal processing module's output links to each other with the man -machine interface module, the signal acquisition module is connected gradually by mutual -inductor, signal conditioning circuit and filter circuit and constitutes, signal processing module includes that the DSP module reaches phase -locked loop circuit and data storage module rather than linking to each other. The utility model relates to a rationally, can guarantee to change along with electric wire netting frequency tracking's result at the interval of the unstable condition down -sampling point of electric wire netting frequency, improve the measuring accuracy, solve the problem of current electric energy meter to containing filtering electric power system and can not accurately measuring.

Description

Based on the mains by harmonics device for measurement of electrical energy of DSP

Technical field

The utility model belongs to power measurement technical field, especially a kind of mains by harmonics device for measurement of electrical energy based on DSP.

Background technology

The appearance of Power Electronic Technique and development, make a large amount of nonlinear-load produce and assemble, harmonic wave injects electrical network in a large number, makes power system voltage, current waveform produce distortion, then causes the waste of net capacity.Electric energy metrical is the foundation of electric system charge, and the existence of a large amount of harmonic wave in electrical network, error in dipping can be produced, cause no small economic loss to power department and power consumer, thus affect the economical operation of electrical network.Therefore, fully realize the impact of harmonic wave on electric energy metrical, adopt the electric energy gauging method designed for harmonic power, developing electric energy meter has far-reaching influence to whole power industry.The electric energy meter of existing market application is count charge for fundamental energy mostly, and cause and fundamental energy and harmonic electric energy cannot be separated, existing can not to the problem containing filtered electrical Force system accurate-metering.

Summary of the invention

The purpose of this utility model is to overcome the deficiencies in the prior art, provides a kind of mains by harmonics device for measurement of electrical energy based on DSP, and solving existing electric energy meter can not the problem of accurate-metering to the electric system containing filtering.

The utility model solves its technical matters and takes following technical scheme to realize:

Based on a mains by harmonics device for measurement of electrical energy of DSP, comprise switch power module, signal acquisition module, signal processing module and human-machine interface module; Switch power module is connected with signal acquisition module, signal processing module and human-machine interface module and is that it is powered; Described signal acquisition module output signal delivers to signal processing module, and the output terminal of described signal processing module is connected with human-machine interface module; Described signal acquisition module is connected and composed successively by mutual inductor, signal conditioning circuit and filtering circuit; Described signal processing module comprises DSP module and coupled phase-locked loop circuit and data memory module; Described phase-locked loop circuit is connected successively by amplifier, phase comparator, low-pass filter, voltage controlled oscillator and divider and forms, the signal that acquisition module exports is connected with amplifier, the output signal of divider output terminal is connected with phase comparator input end, realizes the function of Tracking Frequency of Power Grids.

And described human-machine interface module is made up of liquid crystal display and physical keyboard, this liquid crystal display adopts SED1335 series module.

And, described mutual inductor comprises threephase potential transformer and threephase current transformer, this voltage transformer (VT) uses HPT303 module, this current transformer adopts AKH-0.66 module, described signal conditioning circuit adopts LF258 operational amplifier, the low-pass filter of described filtering circuit to be cutoff frequency be 1.8KHz.

And described data memory module adopts X5045 chip.

And described DSP module adopts TMS320F2407 series module.

Advantage of the present utility model and good effect are:

1, the utility model adopts DSP module to collect a discrete series of line voltage, current signal, quantitative test can go out each harmonic electric energy that harmonic source that nonlinear-load produces carries to electrical network; The result of following the tracks of along with mains frequency at the interval of the situation down-sampling point of mains frequency instability can be ensured and change, improve the accuracy of measurement, solving existing electric energy meter to can not the problem of accurate-metering containing filtered electrical Force system.

2, the utility model is for three-phase four wire system, need to measure three-phase voltage, electric current, simultaneously in order to Real-Time Monitoring center line fault, also neutral voltage will be measured, so have 7 to be measured, the built-in dsp chip of this device itself has the A/D translation function of 16 path 10 positions, content with funtion, and information modulate circuit make signal amplitude meet DSP A/D pin needed for level, eliminate special A/D conversion chip, and the level shifting circuit arranged between A/D conversion chip and DSP, enormously simplify structure, reduce cost.

3, the utility model adopts the DSP of TMS320LF2407 chip, has nearly more than 40 universal input and exports, can greatly simplify hardware configuration, volume, improve system stability and reliability.

The phaselocked loop that what 4, the utility model was taked is on integrated circuit basis, be characterized in supply voltage wide ranges, input impedance is high, and dynamic merit is damaged low.

5, the utility model adopts memory module to store data, avoids because the maloperations such as power-off cause the situations such as loss of data.

Accompanying drawing explanation

Fig. 1 is integrated circuit block scheme of the present utility model;

Fig. 2 is the circuit block diagram of phase-locked loop circuit;

Fig. 3 is DSP module and liquid crystal display, physical keyboard connecting circuit figure.

Embodiment

Below in conjunction with accompanying drawing, the utility model embodiment is further described:

Based on a mains by harmonics device for measurement of electrical energy of DSP, as shown in Figure 1, switch power module 1, signal acquisition module 2, signal processing module 3 and human-machine interface module 4 is comprised; Described signal acquisition module 2 output signal delivers to signal processing module 3, the output terminal of signal processing module 3 is connected with human-machine interface module 4, and described switch power module 1 is connected with signal acquisition module 2, signal processing module 3 and human-machine interface module 4 and is that it is powered.

Described signal acquisition module 2 comprises mutual inductor 201, signal conditioning circuit 202 and filtering circuit 203; Mutual inductor comprises threephase potential transformer and threephase current transformer, and voltage transformer (VT) selects model to be HPT303, and current transformer selects model to be AKH-0.66.The signal of sampling due to mutual inductor is bipolarity and the less signal of amplitude, A/D switched pins demand can not be met, therefore, the signal of mutual inductor sample is delivered to be needed to send in signal conditioning circuit, signal entirety is lifted within 0 to 3V by the operational amplifier being LF258 by the inner model of signal conditioning circuit, thus meet A/D switched pins signal voltage in DSP, operational amplifier output terminal is connected to filtering circuit input end, in the present embodiment, the low-pass filter of filtering circuit to be cutoff frequency be 1.8KHz, omits high fdrequency component.

Described power module 1 provides+5V and+3.3V two kinds of voltages, and+5V is operational amplifier in signal conditioning circuit, filtering circuit is powered; + 3.3V is phase-locked loop circuit, dsp chip, physical keyboard and liquid crystal display provide power supply and provide reference voltage.

Described signal processing module 3 comprises phase-locked loop circuit, DSP module and data memory module three part, as shown in Figure 2, phase-locked loop circuit 301 is made up of amplifier, phase comparator, voltage controlled oscillator (VCO), low-pass filter and divider, threephase potential transformer, input signal that threephase current transformer obtains is connected to signal input part through signal conditioning circuit and filtering circuit, complete amplification in the amplifier, an input end of phase comparator is connected to after shaping, another input end signal of phase comparator takes from the comparison signal Uo of voltage controlled oscillator output, two input end signals are made comparisons and are produced error voltage Ul and export from phase comparator output terminal, this voltage swing is proportional to the phase differential of Ui and Uo signal, after error voltage delivers to low-pass filter removal high fdrequency component afterwards, obtain control voltage Ud and add to voltage controlled oscillator input end, adjustment VCO oscillation frequency makes it close with signal frequency, output terminal enters phase comparator I again through divider, continue to make comparisons with input signal Ui, until it is consistent with signal frequency to meet sample frequency, thus finally realize signal phase genlocing, and gained signal is delivered to the XINT1 pin of DSP, what DSP module adopted is TMS320F2407 series, receives the signal from acquisition module and phase-locked loop circuit, data memory module adopts X5045 chip, and I/O interface and the X4045 sheet of dsp chip select input end be connected, SPISIMO is connected with serial data input SI, and SPISIMI is connected with serial data output terminal SO, and SPICLK is connected with serial clock terminal SCK.

Described human-machine interface module 4 comprises liquid crystal display and physical keyboard; Liquid crystal display adopts SED1335 series, and as shown in Figure 3, IOPA0 to the IOPA7 of DSP is connected with DB0 to the DB7 of SED1335 as data-interface; IOPB0 and read operation signal pins be connected; IOPB1 and write operation signal pin be connected; IOPB2 and sheet select input end be connected as chip selection signal; IOPB3 and AO is connected as address wire, and wherein AO=1 is write command code and read data, and AO=0 is for writing data parameters and reading busy mark; VDD pin meets+3.3V, VSS ground connection; Physical keyboard is connected with DSP external interrupt XINT2 pin, and when a key is pressed, DSP produces interrupt instruction, and kernel immediately allows keyboard be in input command status; Pin IOPCO to the IOPC3 corresponding to I/O mouth line of DSP connects each button of keyboard, the sweep trace of composition keyboard, and performs the function program corresponding to this key assignments.

Principle of work of the present utility model and process are: first, and in order to the high voltage and current obtained from electrical network signal being converted into the signal that A/D switched pins is suitable for, we adopt voltage, current transformer and signal conditioning circuit to obtain.Simultaneously in order to avoid there is spectral leakage, by our unwanted HFS in low-pass filter elimination signal; A/D switched pins in DSP is the analog voltage collected and current signal, be converted to digital voltage and current signal, then in DSP, utilize Fast Fourier Transform (FFT) method (FFT) that the discrete series data that A/D is converted to are become the value of each harmonic component, and then calculate fundamental power and each harmonic power according to harmonic power computing method again, every phase each harmonic electric energy is just obtained to the integration of time; In signal acquisition process, except GPRS every road signal magnitude, phase relation also needs to understand, here we take phase-locked loop circuit to obtain accurate information, by changing the frequency of voltage controlled oscillator, till sample frequency is synchronous with signal frequency, reach the object of following the tracks of grid cycle change; The most signal collected TMS320LF2407 chip delivering to DSP, complete series of computation, control demonstrate result on a liquid crystal display by human-machine interface module, the operation of various function can be carried out to system by keyboard simultaneously, the I/O interface of dsp chip is connected with keyboard as the sweep trace of keyboard, keyboard is also connected with the XINT2 pin of DSP simultaneously, is judged the generation of button by interrupt instruction.DSP computing the data obtained can be delivered in the middle of data-carrier store simultaneously, prevents from causing loss of data because of power-off.

The utility model is based on the mains by harmonics device for measurement of electrical energy of DSP, components and parts used and parts are all known by those skilled in the art, can by commercially available or oneself easy making, the mode of connection of the connected mode between all components and parts, the mounting means of parts and power circuit is also known by those skilled in the art.

The utility model is not addressed part and is applicable to prior art.

It is emphasized that; embodiment described in the utility model is illustrative; instead of it is determinate; therefore the utility model comprises the embodiment be not limited to described in embodiment; every other embodiments drawn according to the technical solution of the utility model by those skilled in the art, belong to the scope of the utility model protection equally.

Claims

1. based on a mains by harmonics device for measurement of electrical energy of DSP, it is characterized in that: comprise switch power module, signal acquisition module, signal processing module and human-machine interface module; Switch power module is connected with signal acquisition module, signal processing module and human-machine interface module and is that it is powered; Described signal acquisition module output signal delivers to signal processing module, and the output terminal of described signal processing module is connected with human-machine interface module; Described signal acquisition module is connected and composed successively by mutual inductor, signal conditioning circuit and filtering circuit; Described signal processing module comprises DSP module and coupled phase-locked loop circuit and data memory module; Described phase-locked loop circuit is connected successively by amplifier, phase comparator, low-pass filter, voltage controlled oscillator and divider and forms, the signal that acquisition module exports is connected with amplifier, the output signal of divider output terminal is connected with phase comparator input end, realizes the function of Tracking Frequency of Power Grids.

2. the mains by harmonics device for measurement of electrical energy based on DSP according to claim 1, is characterized in that: described human-machine interface module is made up of liquid crystal display and physical keyboard, and this liquid crystal display adopts SED1335 series module.

3. the mains by harmonics device for measurement of electrical energy based on DSP according to claim 1, it is characterized in that: described mutual inductor comprises threephase potential transformer and threephase current transformer, this voltage transformer (VT) uses HPT303 module, this current transformer adopts AKH-0.66 module, described signal conditioning circuit adopts LF258 operational amplifier, the low-pass filter of described filtering circuit to be cutoff frequency be 1.8KHz.

4. the mains by harmonics device for measurement of electrical energy based on DSP according to claim 1, is characterized in that: described data memory module adopts X5045 chip.

5. the mains by harmonics device for measurement of electrical energy based on DSP according to any one of Claims 1-4, is characterized in that: described DSP module adopts TMS320F2407 series module.