CN104407208A - System for relatively accurately measuring resistive current on basis of positive and negative transform of FFT (fast Fourier transform) by circuit energy - Google Patents

Abstract

The invention relates to a system for relatively accurately measuring resistive current on the basis of positive and negative transform of FFT (fast Fourier transform) by circuit energy. The system comprises an energy collection device and a device for relatively accurately measuring the resistive current on the basis of positive and negative transform of FFT, and solves power supply problems while meeting existing data monitoring conditions. The device is an online arrester monitoring device capable of supporting a DSP (digital signal processor) as a controller under the condition of microampere leakage current.

Description

A kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT

Technical field

The invention belongs to power network monitoring field, be specifically related to lightning arrester monitoring system field.

Background technology

Existing lightning arrester monitoring system utilizes the electric current of mode monitoring stream through lightning arrester of PT obtaining current, and the present situation that this mode can not adapt to existing intelligent station, transformer station's transmission system, high ferro electric power arrange PT nowhere, for overcoming the above problems, the present invention adopts the measurement problem of method and the related device solution lightning arrester measured based on Fourier FFT positive inverse transformation relative calibration current in resistance property.

Along with power network development is that arrester on-line monitoring system is crucial to efficiently and accurately Real-Time Monitoring always, but current existing monitoring equipment, as traditional analog table exists accuracy, can only monitor total current simultaneously cannot teletransmission, long-term consistency and stability problem is there is in harsh rugged surroundings, existing electronic detecting device, there is power supply and transmission problem, power supply many employings externally fed or powered battery mode, all there is the problem such as engineering or battery life, the many employings of transmission are wired, wireless, with conventional fibre optic communication mode, Keep Clear-High Voltage in wired existence introducing, wireless in transformer station existence and stability problem, conventional fibre optic communication is larger to power consumption requirements, external power source can bring safety and construction problem according to actual field service condition, powered battery is owing to realizing cycle charging, there is certain life-span, and lightning arrester is in outdoor operation, difference variation is huge, different geographical and Various Seasonal all can cause certain influence to battery, increase the failure rate of lightning arrester monitoring equipment, general DSP belongs to high side controller, larger to power consumption requirements.Solve powerup issue in order to solve meeting under available data monitoring, ad hoc meter is a kind of can meet under microampere order Leakage Current, support to take DSP as the lightning arrester on-Line Monitor Device that controller realizes.

Summary of the invention

Present invention achieves one and only gather monitoring device with a kind of lightning arrester electric leakage that Leakage Current just can realize without the need to externally fed, emphasis is the collect and transmit task realizing realizing DSP under microampere order is revealed.

When having Leakage Current through current sampling unit and limit volt rectification unit, direct current is made into through limit volt rectification circuit table exchange current, capacitor storage unit electric capacity is charged, along with time voltage increases, when increasing to trigger voltage 3.3V, interval insulating power supply starts starts working, the utilization of power DC power delivery of filling in electric capacity to DC power output end, voltage stabilizing 3.3V unit, after DC exports a stable 3.3V voltage, triggering dsp processor is started working, dsp processor opens low-power consumption ADC amplifier unit fast, start A/D overvoltage sampling unit, start sample streams excess current sampling unit electric current, after quick sampling completes, in order to save electricity, DSP closes rapidly low-power consumption ADC amplifier unit and A/D overvoltage sampling unit saves energy, collection signal is carried out time domain to frequency domain conversion post analysis first-harmonic and multiple harmonic data by high scheduling algorithm FFT by dsp processor, nearest calculating obtains and finally requires parameter, after calculating completes, data are packed, a high frequency 1MHZ carrier signal LED radiating circuit is modulated by Manchester's cde mode, after completing data transmitting, DSP enters super low-power consumption park mode at once, once complete test to drop in 2.5V from 3.3V at interval isolation DC electric power output voltage and complete.Because Leakage Current is uninterrupted long-term existence, front end energy collection unit can continue to obtain electric energy, when voltage is charged to interval isolation DC power initiation point, metering circuit can a circulation previous step data acquisition surveying work again, this circuit measuring limits by path Leakage Current size, when electric current is large time, unit interval pendulous frequency increases, otherwise reduces.

Main electrical current sampling unit uses the difference amplifier of high input impedance by sampling resistor, realize path Leakage Current and convert ratio-voltage relation to, realize filtering scale amplifying through low-power consumption AGC amplifier unit and realize A/D12 position ability in sampling by DSP control A/D over-sampling element circuit, DSP is with the sampling rate of 1.2K, to sample 4096 points, changed by fft algorithm, the first-harmonic and each harmonic that obtain sample rate current obtain high-precision current sampled value;

Power pack by, ac-dc converter circuit, energy collection unit is charged, comparer is used to judge charging amplitude in this circuit, whole measurement to be returned the impact of current non-linear to reduce amplitude limit rectification unit, energy collection unit sampling farad capacitive way stored charge, judge that charging voltage arrives 3.3V by comparer, then interval isolation DC-DC Switching Power Supply is opened, energy conversion is inner to output capacitor, when output capacitance voltage can reach 3.3V, automatic startup DSP carries out work, after DSP work, startup low-power consumption AGC amplifier unit and A/D over-sampling unit realize signals collecting, valid data are analyzed again by inner Fourier FFT conversion process, afterwards valid data are transferred to receiving end data by light form by LED pulse emitting units.

Its concrete technical scheme is as follows:

A kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT, the device comprising energy collecting device and measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT, described energy collecting device comprises the limit volt rectification unit connected successively, energy collection unit, low-power consumption DC isolating converter unit, rectifying and voltage-stabilizing filtering output unit and with limit lie prostrate rectification unit, energy collection unit, the low power consumption comparator control module that low-power consumption DC isolating converter unit is connected, described limit volt rectification unit is directly connected in tested loop, when having electric current to flow through in tested loop, be converted to DC voltage form through limit volt rectification unit to charge to energy collection unit, energy collection unit adopts capacitive way stored energy, the described energy function utilizing energy collecting device to collect based on the device of the relatively accurate current in resistance property measurement of the positive inverse transformation of Fourier FFT, comprise accurate AGC amplifier, low-pass filter, accurate zero-crossing comparator, time-delay trigger, ADC triggers sampling unit, sampling initial phase angle control module, MCU controller, described accurate AGC amplifier, low-pass filter, ADC triggers sampling unit and MCU controller connects successively, accurate AGC amplifier is also connected with MCU controller, described accurate zero-crossing comparator connects low-pass filter, ADC triggers sampling unit, time-delay trigger and MCU controller, described time-delay trigger is also connected with ADC and triggers sampling unit and MCU controller, described sampling initial phase angle control module is connected with MCU controller.

Preferably, described accurate AGC amplifier is used for amplification input signal, described low-pass filter plays filter action for realizing to the input signal in the accurate AGC amplifier of the process of more than 1KHz, after filtering process, accurate zero-crossing comparator is sent on one tunnel, one tunnel send ADC triggering collection unit etc. to be collected, described accurate zero-crossing comparator is used for forward signal zero crossing being detected when it, namely a rising edge signal is exported, one tunnel is to time-delay trigger, one tunnel realizes the frequency Real-Time Monitoring to input signal to MCU controller, described time-delay trigger triggers ADC triggering collection unit after being used for the rising edge signal time delay setting value exported according to accurate zero-crossing comparator, described ADC triggering collection unit does not work under normal circumstances, when time-delay trigger is to an ADC triggering collection unit signal, ADC triggering collection unit brings into operation ADC collecting work, described ADC trigger collection element circuit coordinates MCU controller to the discrete acquisitions of input signal, after completing sampled point number, by realizing the analyzing and processing to sampled signal based on the relatively accurate current in resistance property measuring method of the positive inverse transformation of Fourier FFT, obtain total current and current in resistance property.

Described sampling initial phase angle control module is used in the inaccurate situation of current in resistance property measured, and realizes the adjustment to the discrete sampling first-harmonic first phase angle in algorithm by the delay value of MUC controller adjustment time-delay trigger setting.

Described energy collecting device comprise the limit volt rectification unit, energy collection unit, low-power consumption DC isolating converter unit, the rectifying and voltage-stabilizing filtering output unit that connect successively and lie prostrate rectification unit with limit, low power consumption comparator control module that energy collection unit, low-power consumption DC isolating converter unit are connected, described limit volt rectification unit is directly connected in tested loop, when having electric current to flow through in tested loop, be converted to DC voltage form through limit volt rectification unit to charge to energy collection unit, energy collection unit adopts capacitive way stored energy.

Described limit volt rectification unit is located in the series circuit of lightning arrester Leakage Current, comprise low loss capacitance C6, TVS pipe V1, NMOS tube Q1, PMOS Q2, NMOS tube Q7 and PMOS Q8, described low loss capacitance C6 and TVS pipe V1 are in parallel and be located between the first input end J1 of lightning arrester Leakage Current and the second input end J2, the drain electrode of described NMOS tube Q1 and first input end J1, the grid of NMOS tube Q7 and PMOS Q8 is connected, the grid of NMOS tube Q1 is connected with the grid of the drain electrode of NMOS tube Q7 and PMOS Q2, the source electrode of NMOS tube Q1 is connected in energy collection unit and is connected with the source electrode of NMOS tube Q7, the drain electrode of described NMOS tube Q7 is connected to the second input end J2, and its grid is also connected with the grid of PMOS Q8, the source electrode of described PMOS Q2 is connected with the source electrode of PMOS Q8, and is connected to energy collection unit, and the grid of PMOS Q2 is connected with the drain electrode of NMOS tube Q7 and PMOS Q8.

Described energy collection unit comprises 3.3v limit volt stabilivolt D1 and energy storage farad capacitor C1, described 3.3v limit volt stabilivolt D1 and energy storage farad capacitor C1 is connected between the source electrode of PMOS Q2, the source electrode of PMOS Q8 and NMOS tube Q1, NMOS tube Q7, wherein, the positive pole of 3.3v limit volt stabilivolt D1 is connected with the source electrode of NMOS tube Q1, NMOS tube Q7, and the negative pole of 3.3v limit volt stabilivolt D1 is connected with the source electrode of PMOS Q2, PMOS Q8.

Described low power consumption comparator control module comprises comparer U1, voltage stabilizer U2, nmos switch pipe and resistance R1, R2, R3, R4, R5, R6, R7, first input end and the 3.3v of described voltage stabilizer U2 limit the positive pole lying prostrate stabilivolt D1 to be connected, second input end is through resistance R5, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to connect, the output terminal of voltage stabilizer U2 limits the negative pole of volt stabilivolt D1 to be connected through resistance R2 and 3.3v, described comparer U1 positive input+IN limits the negative pole of volt stabilivolt D1 to connect through resistance R1 and 3.3v, the positive pole of volt stabilivolt D1 is limit to connect through resistance R4 and 3.3v, comparer U1 reverse input end-IN limits the positive pole of volt stabilivolt D1 to connect through resistance R6 and 3.3v, power input V+ and the 3.3v of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected, the output end vo ut of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected through resistance R3 and 3.3v, Voltage Reference basic point GND and the 3.3v of comparer U1 limits the positive pole of volt stabilivolt D1 to connect, described nmos switch pipe comprises NMOS tube Q9, NMOS tube Q10, the drain electrode of described NMOS tube Q9 is connected with comparer U1 reverse input end-IN through resistance R7, through resistance R7, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to be connected, NMOS tube Q9, the source electrode of NMOS tube Q10 all limits the positive pole lying prostrate stabilivolt D1 to be connected with 3.3v, the grid of NMOS tube Q9 is connected with the grid of NMOS tube Q10 and limits the negative pole lying prostrate stabilivolt D1 to be connected through resistance R3 and 3.3v.

Described low-power consumption DC isolating converter unit comprises transformer T1, electric capacity C3, C2, C4, diode D2, D5, PMOS Q11, electric capacity C2 and diode D2 is serially connected with between inductance L 1 two ends in described transformer T1 primary coil, in described transformer T1 primary coil, the p8 end of inductance L 2 connects the drain electrode of NMOS tube Q10 through diode D5, in described transformer T1 primary coil, the p7 end of inductance L 2 connects the grid of PMOS Q11 through electric capacity C3, the source electrode of PMOS Q11 connects the drain electrode of NMOS tube Q10, the p7 end of inductance L 2 is through electric capacity C3, resistance R8 connects the drain electrode of NMOS tube Q10, electric capacity C4 is serially connected with between inductance L 3 two ends in transformer T1 secondary coil.

Described rectifying and voltage-stabilizing filtering output unit comprises the diode bridge rectifier circuit and connected voltage regulation filtering output circuit that are made up of NMOS tube Q3, NMOS tube Q4, PMOS Q5 and PMOS Q6.

Accompanying drawing explanation

Fig. 1 is structural representation of the present invention;

Fig. 2 is energy collecting device structural representation;

Fig. 3 is the apparatus structure schematic diagram measured based on Fourier FFT positive inverse transformation relative calibration current in resistance property.

Fig. 4 is energy collecting device electrical block diagram;

Embodiment

Below in conjunction with drawings and Examples, the present invention will be further described.

As shown in Figure 2, for the energy collecting device of lightning arrester monitoring system, connected to form successively by limit volt rectification unit, energy collection unit, low-power consumption DC isolating converter; Limit of asking for volt rectification unit is directly connected in tested loop, and when having electric current to flow through in loop, be converted to DC voltage form to the charging of energy collection unit capacitor energy through limit volt rectification unit, energy collection unit adopts capacitive way stored energy.

Described limit volt rectification unit is located in the series circuit of lightning arrester Leakage Current, by low loss capacitance, TVS pipe, 3.3v limit volt stabilivolt and four metal-oxide-semiconductor structure compositions, for exchange current is made into direct current, charge to the capacitor storage unit of energy collection unit.

In circuit, V1, C6 cause damage in order to the pulse that prevents from being struck by lightning instantaneously is impacted metal-oxide-semiconductor rectification unit circuit, D1 selects the minimum voltage stabilizing quiescent current of low-power consumption to be less than 5uA stabilivolt, reduce charge loss electric current, restriction charging voltage is within 3.3V, because D1 and metal-oxide-semiconductor are nonlinear device, if under charging voltage does not do any restriction, can increase along with voltage, more than more than 3.3V, nonlinear device impact starts to manifest, cause the non-linear aggravation of loop current, loop current waveform distorts, especially for three, the impact of quintuple harmonics is remarkable.

Described capacitor storage unit is made up of ultra-low power consumption comparer, super low-power consumption voltage stabilizer, energy storage farad capacitor, nmos switch pipe, for collecting the direct current that limit volt rectification unit transmits, directly be stored in accumulator farad capacitor, when farad capacitor terminal voltage is charged to 3.3V, comparer work exports high level, NMOS tube is open-minded, exports 3.3V voltage to low-power consumption DC isolating converter, starts the work of shaking and the energy in accumulator electric capacity is transformed into output terminal by transformer mode.

Rectification circuit adopts unconventional diode bridge rectifier circuit, and under solving low input current, diode exists up to 0.7V pressure drop, and due to diode is nonlinear device, causes non-linear effects equally to loop current.

In order to reduce circuit oneself power consumption, avoid energy waste, in circuit, R1, R3, R4, R5, R6, R7 resistance all selects the above resistance of megaohm, and simultaneously U1, U2 select ultra-low power consumption comparer and parameter voltage stabilizator, to make in energy collection process loop works current power dissipation within 12uA.

Described interval isolation DC power supply is made up of rectification unit, self-oscillation unit, rectification stable pressuring unit, for receiving electric energy that capacitor storage unit transmits and being transferred to lightning arrester monitoring system.

Low-power consumption DC isolating converter, for unconventional complicated DC-DC switch power module, adopt many coilings one group of coil inductance L and electric capacity C3 resistance R8, metal-oxide-semiconductor Q11, diode D5, automatic oscillator is formed according to input voltage amplitude, and the oscillator that non-traditional power consumption is large, greatly reduce DC Switching Power Supply static working current, power consumption≤10uA, with the complexity of circuit, by the energy in electric capacity C1, be transformed into output terminal by Switching Power Supply mode.

When there being electric current to flow through in loop, Q2, Q7 and Q1, Q8 alternate conduction, be converted to direct current, through the voltage stabilizing of D1 limit volt, C1 farad capacitor is charged, stabilivolt U2 work output 2.0V reference voltage, through R5, R6 dividing potential drop 1.0V is to comparer U1 reverse input end-IN, time C1 terminal voltage is charged to 3.3V, through R1, positive input+IN the voltage of R4 electric resistance partial pressure input comparator U1 is greater than reverse input end reference voltage, comparer U1 input high level, metal-oxide-semiconductor Q9, Q10 conducting, after R7 and R6 parallel connection, dividing potential drop reduces the reverse input voltage of input comparator U1, output high level can both be stablized before keeping U1 when C1 terminal voltage is reduced to 1.6V, keep Q9, Q10 constant conduction, Q10 conducting rear end isolation DC power work, C3, R8 and T1 (p7-p8) transformer combination concussion, is transformed into output port, entered Q3, Q6 and Q4, Q5 alternation is transformed to Rectified alternating current, a stable DC voltage is exported through D3, D4 voltage stabilizing.

The invention solves current existing Switching Power Supply be all in the form of voltage and quiescent dissipation all at least a few more than mA, loop current cannot be applied to only in tens uA low current ac current source loop circuits.

As shown in Figure 3, the device circuit measured based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT designs as follows: circuit is made up of accurate AGC amplifier, 1KHz low-pass filter, accurate zero-crossing comparator, time-delay trigger, ADC triggering sampling unit, sampling initial phase angle control module, MCU controller.

Accurate AGC amplifier: complete the amplification to input signal, by AGC automatic gain control circuit, its input signal being amplified in a suitable amplitude range, is that post-processed prepares;

Low-pass filter: realize playing filter action to frequency input signal at more than 1KHz, the noise disturbance reduced in useful signal causes measuring error, for in the faint especially situation of input signal amplitude, with a large amount of interfere informations in signal, this type of information is exaggerated simultaneously, the accurate Zero-cross comparator of rear end can be caused accurately to judge the zero crossing of useful signal thus to cause error if do not add process

Accurate zero-crossing comparator: realize the judgement work to input signal zero crossing, realize rear end and the frequency of input signal is judged, thus be that the synchronized sampling of rear end is prepared;

Time-delay trigger: when accurate zero-crossing comparator detects forward signal zero crossing, namely export a rising edge signal, time-delay trigger triggers ADC triggering collection unit according to after this rising edge signal time delay setting value;

ADC triggering collection unit: this unit does not work under normal circumstances, when time-delay trigger is to an ADC triggering collection unit signal, ADC triggering collection unit brings into operation ADC collecting work;

Gather initial phase angle control module: this functional unit realizes, to the discrete sampling first-harmonic angle of arrival adjustment task in algorithm, making it meet the demands;

Principle of work process: total current is after sampling resistor RS, enter accurate AGC amplifier, signal after amplifying, pass through low-pass filter, after filtering process, accurate zero-crossing comparator is sent on one tunnel, one tunnel send ADC triggering collection unit etc. to be collected, accurate zero-crossing comparator operation detection exports a rising edge trigger pip to during positive going zeror crossing point, one tunnel is to time-delay trigger, one tunnel realizes the frequency Real-Time Monitoring to input signal to MCU controller, for realizing synchro measure requirement, time-delay trigger is according to setting delay value, after time delay certain hour reaches, trigger ADC collecting unit circuit working, ADC collecting unit circuit coordinates MCU controller to the discrete acquisitions of input signal, after completing sampled point number, above-mentioned algorithm realization is pressed to the analyzing and processing of sampled signal by Fourier transformation method, obtain total current and current in resistance property, but under the current in resistance property measured is forbidden situation, illustrate that the tracking of circuit to sampling initial phase angle and true total current and current in resistance property angle is not accurate enough, now by adjustment sampling initial phase angle control module circuit, can realize meeting the tracking of angle, realize the Measurement accuracy work of current in resistance property.

Embodiment one

By the full volt-ampere characteristic test to Zinc-Oxide Arrester test product, zinc paste ZnO arrester characteristic working curve can be divided into two large sections, small area analysis section linearity range, and big current section inelastic region; During normal operation, oxidation zinc metal sheet working point is usually all in small area analysis and linearity range runs;

According to test small area analysis linearity range, the equivalent model of Zinc-Oxide Arrester is the parallel way realization of Rx and Cx.

Reference signal terminal voltage is established according to RC capacitance-resistance characteristic in parallel in Rx, electric current is expressed as electric current in Cx is

According to theory can be through the total current of Zinc-Oxide Arrester i is for flowing through the circuital effective value of Zinc-Oxide Arrester, f ₀for fundamental frequency, θ ₀for reference initial phase angle, θ ₁for current in resistance property i _rwith total current i angle, because of I _r=Icos (θ ₁), as long as so obtain total current I and θ by measurement ₁i can be obtained _rvalue.

If synchronized sampling rate is Fs, measured signal fundamental frequency (i.e. fundamental frequency) is f ₀;

Synchronized sampling rate requires as itself and measured signal frequency ratio are integral multiple relation, i.e. Fs/f ₀=Nk; (Nk is integer), real-time follow-up of sampling in circuit compensates Fs to reach synchronized sampling requirement, according to measured signal fundamental frequency f ₀variation range is between 45Hz ~ 65Hz, and Nk can value be Nk=20;

Sampling rate Fs is chosen as Fs=Nk*f ₀=20* (45Hz ~ 65Hz)=0.99KHz ~ 1.3KHz.

Analyze requirement according to sampling thheorem and three quintuple harmonicss, sampling rate Fs selects to meet the demands, and in order to accurate analysis with prevent spectral leakage, continuous sampling is counted and is set to N=8192, and minimal physical resolution is that 0.12Hz meets and measures requirement.

As shown in Figure 3, by Rs sampling resistor to discrete sampling circuital in Zinc-Oxide Arrester according to lightning arrester practical operation situation, major harmonic component mainly concentrates in three quintuple harmonicss, so Main Analysis first-harmonic and three quintuple harmonicss, frequency-region signal conversion elimination higher hamonic wave is changed to by Fourier FFT time-domain signal, recycling FFT inverse transformation reduction discrete sample signals can obtain

Namely

$i_{\left(n\right)}=\sqrt{2}\mathrm{ISin}(2\mathrm{\π}{f}_0\mathrm{n\Δt}+{\mathrm{\θ}}_0+{\mathrm{\θ}}_2)+\sqrt{2}{I}_3\mathrm{Sin}(2\mathrm{\π}3f_0\mathrm{n\Δt}+{\mathrm{\θ}}_3)+\sqrt{2}{I}_5\mathrm{Sin}(2\mathrm{\π}5f_0\mathrm{n\Δt}+{\mathrm{\θ}}_5);$

Current weight I, I of first-harmonic and three quintuple harmonicss is obtained respectively by above-mentioned expression formula ₃, I ₅, and corresponding sampling initial phase θ ₂, θ ₃, θ ₅; Under first not considering three quintuple harmonicss, namely with true by the total current in Zinc-Oxide Arrester compare, learn and can meet θ ₁=θ ₂θ is tried to achieve after converting according to discrete sampling FFT in situation ₁, according to I _r=Icos (θ ₁), can obtain the current in resistance property under first-harmonic, same method obtains the current in resistance property under three quintuple harmonicss respectively, and total current in resistance property is the mean value of each harmonic vector sum.

Operating characteristic according to Zinc-Oxide Arrester is tested, and in the main linearly section of small area analysis section, meets θ to reach ₁=θ ₂, adopt herein and carry out calibration steps for the first time and realize θ ₁=θ ₂; Because θ ₁, θ ₂actual angle scope, all between (-π-+π), coordinates controller by control hardware circuit, adjusts and can realize θ to the control of total current discrete sampling starting sample position ₁=θ ₂the accuracy that small area analysis section is measured can be ensured in long-time running, for big current non-linear section, in the signal of sampling, three quintuple harmonicss obviously have aggravation phenomenon, because this algorithm is that mean value under each harmonic wave of work is to calculate total current in resistance property, so still Measurement accuracy requirement can be met, namely the monitoring task to current in resistance property can be met by test the method;

As shown in Figure 3, hardware circuit design of the present invention is as follows: circuit is made up of accurate AGC amplifier, 1KHz low-pass filter, accurate zero-crossing comparator, time-delay trigger, ADC triggering sampling unit, sampling initial phase angle control module, MCU controller:

Accurate AGC amplifier: complete the amplification to input signal, by AGC automatic gain control circuit, its input signal being amplified in a suitable amplitude range, is that post-processed prepares.

Low-pass filter: realize playing filter action to frequency input signal at more than 1KHz, the noise disturbance reduced in useful signal causes measuring error, for in the faint especially situation of input signal amplitude, with a large amount of interfere informations in signal, this type of information is exaggerated simultaneously, the accurate Zero-cross comparator of rear end can be caused accurately to judge the zero crossing of useful signal thus to cause error if do not add process.

Accurate zero-crossing comparator: realize the judgement work to input signal zero crossing, realize rear end and the frequency of input signal is judged, thus be that the synchronized sampling of rear end is prepared.

Time-delay trigger: when accurate zero-crossing comparator detects forward signal zero crossing, namely export a rising edge signal, time-delay trigger triggers ADC triggering collection unit according to after this rising edge signal time delay setting value.

ADC triggering collection unit: this unit does not work under normal circumstances, when time-delay trigger is to an ADC triggering collection unit signal, ADC triggering collection unit brings into operation ADC collecting work.

Gather initial phase angle control module: this functional unit realizes the discrete sampling first-harmonic first phase angular setting task in algorithm, makes it meet θ ₁=θ ₂requirement.

Principle of work process: total current is after sampling resistor Rs, enter accurate AGC amplifier, signal after amplifying, pass through low-pass filter, after filtering process, accurate zero-crossing comparator is sent on one tunnel, one tunnel send ADC triggering collection unit etc. to be collected, accurate zero-crossing comparator operation detection exports a rising edge trigger pip to during positive going zeror crossing point, one tunnel is to time-delay trigger, one tunnel realizes the frequency Real-Time Monitoring to input signal to MCU controller, for realizing synchro measure requirement, time-delay trigger is according to setting delay value, after time delay certain hour reaches, trigger ADC collecting unit circuit working, ADC collecting unit circuit coordinates MCU controller to the discrete acquisitions of input signal, after completing sampled point number, above-mentioned algorithm realization is pressed to the analyzing and processing of sampled signal by Fourier transformation method, obtain total current and current in resistance property, when the current in resistance property measured is inaccurate, illustrate that the tracking of circuit to sampling initial phase angle and true total current and current in resistance property angle is not accurate enough, now by adjustment sampling initial phase angle control module circuit, can realize meeting θ to the tracking of angle ₁=θ ₂, realize the Measurement accuracy work of current in resistance property.

Described energy collecting device, comprise the limit volt rectification unit, energy collection unit, low-power consumption DC isolating converter unit, the rectifying and voltage-stabilizing filtering output unit that connect successively and lie prostrate rectification unit with limit, low power consumption comparator control module that energy collection unit, low-power consumption DC isolating converter unit are connected, described limit volt rectification unit is directly connected in tested loop, when having electric current to flow through in tested loop, be converted to DC voltage form through limit volt rectification unit to charge to energy collection unit, energy collection unit adopts capacitive way stored energy.

Described limit volt rectification unit is located in the series circuit of lightning arrester Leakage Current, comprise low loss capacitance C6, TVS pipe V1, NMOS tube Q1, PMOS Q2, NMOS tube Q7 and PMOS Q8, described low loss capacitance C6 and TVS pipe V1 are in parallel and be located between the first input end J1 of lightning arrester Leakage Current and the second input end J2, the drain electrode of described NMOS tube Q1 and first input end J1, the grid of NMOS tube Q7 and PMOS Q8 is connected, the grid of NMOS tube Q1 is connected with the grid of the drain electrode of NMOS tube Q7 and PMOS Q2, the source electrode of NMOS tube Q1 is connected in energy collection unit and is connected with the source electrode of NMOS tube Q7, the drain electrode of described NMOS tube Q7 is connected to the second input end J2, and its grid is also connected with the grid of PMOS Q8, the source electrode of described PMOS Q2 is connected with the source electrode of PMOS Q8, and is connected to energy collection unit, and the grid of PMOS Q2 is connected with the drain electrode of NMOS tube Q7 and PMOS Q8.For exchange current is made into direct current, to charge to the capacitor storage unit of energy collection unit.In circuit, TVS pipe V1, low loss capacitance C6 cause damage in order to the pulse that prevents from being struck by lightning instantaneously is impacted metal-oxide-semiconductor rectification unit circuit.

Described energy collection unit comprises 3.3v limit volt stabilivolt D1 and accumulator farad capacitor C1, described 3.3v limit volt stabilivolt D1 and accumulator farad capacitor C1 is connected between the source electrode of PMOS Q2, the source electrode of PMOS Q8 and NMOS tube Q1, NMOS tube Q7, wherein, the positive pole of 3.3v limit volt stabilivolt D1 is connected with the source electrode of NMOS tube Q1, NMOS tube Q7, and the negative pole of 3.3v limit volt stabilivolt D1 is connected with the source electrode of PMOS Q2, PMOS Q8.For collecting the direct current that limit volt rectification unit transmits, be directly stored in accumulator farad capacitor C1.3.3v limit volt stabilivolt D1 selects the minimum voltage stabilizing quiescent current of low-power consumption to be less than 5uA stabilivolt, reduce charge loss electric current, limit charging voltage within 3.3V, because 3.3v limit volt stabilivolt D1 and metal-oxide-semiconductor are nonlinear device, if under charging voltage does not do any restriction, can increase along with voltage, more than more than 3.3V, nonlinear device impact starts to manifest, and causes the non-linear aggravation of loop current, loop current waveform distorts, especially for three, the impact of quintuple harmonics is remarkable.

Described low power consumption comparator control module comprises comparer U1, voltage stabilizer U2, nmos switch pipe and resistance R1, R2, R3, R4, R5, R6, R7, first input end and the 3.3v of described voltage stabilizer U2 limit the positive pole lying prostrate stabilivolt D1 to be connected, second input end is through resistance R5, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to connect, the output terminal of voltage stabilizer U2 limits the negative pole of volt stabilivolt D1 to be connected through resistance R2 and 3.3v, described comparer U1 positive input+IN limits the negative pole of volt stabilivolt D1 to connect through resistance R1 and 3.3v, the positive pole of volt stabilivolt D1 is limit to connect through resistance R4 and 3.3v, comparer U1 reverse input end-IN limits the positive pole of volt stabilivolt D1 to connect through resistance R6 and 3.3v, power input V+ and the 3.3v of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected, the output end vo ut of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected through resistance R3 and 3.3v, Voltage Reference basic point GND and the 3.3v of comparer U1 limits the positive pole of volt stabilivolt D1 to connect, described nmos switch pipe comprises NMOS tube Q9, NMOS tube Q10, the drain electrode of described NMOS tube Q9 is connected with comparer U1 reverse input end-IN through resistance R7, through resistance R7, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to be connected, NMOS tube Q9, the source electrode of NMOS tube Q10 all limits the positive pole lying prostrate stabilivolt D1 to be connected with 3.3v, the grid of NMOS tube Q9 is connected with the grid of NMOS tube Q10 and limits the negative pole lying prostrate stabilivolt D1 to be connected through resistance R3 and 3.3v.In order to reduce circuit oneself power consumption, avoid the waste of energy, in circuit, R1, R3, R4, R5, R6, R7 resistance all selects the above resistance of megaohm, simultaneously comparer U1, voltage stabilizer U2 select ultra-low power consumption comparer and super low-power consumption voltage stabilizer, to make in energy collection process loop works current power dissipation within 12uA.When accumulator farad capacitor C1 terminal voltage is charged to 3.3V, ultra-low power consumption comparer U1 works and exports high level, nmos switch pipe is open-minded, export 3.3V voltage to low-power consumption DC isolating converter unit, start the work of shaking and the energy in accumulator farad capacitor C1 is transformed into output terminal by transformer mode.

Described low-power consumption DC isolating converter unit comprises transformer T1, electric capacity C3, C2, C4, diode D2, D5, PMOS Q11, electric capacity C2 and diode D2 is serially connected with between inductance L 1 two ends in described transformer T1 primary coil, in described transformer T1 primary coil, the p8 end of inductance L 2 connects the drain electrode of NMOS tube Q10 through diode D5, in described transformer T1 primary coil, the p7 end of inductance L 2 connects the grid of PMOS Q11 through electric capacity C3, the source electrode of PMOS Q11 connects the drain electrode of NMOS tube Q10, the p7 end of inductance L 2 is through electric capacity C3, resistance R8 connects the drain electrode of NMOS tube Q10, electric capacity C4 is serially connected with between inductance L 3 two ends in transformer T1 secondary coil.Low-power consumption DC isolating converter unit, for unconventional complicated DC-DC switch power module, adopt many coilings one group of coil inductance L and electric capacity C3 resistance R8, metal-oxide-semiconductor Q11, diode D5, automatic oscillator is formed according to input voltage amplitude, and the oscillator that non-traditional power consumption is large, greatly reduce DC Switching Power Supply static working current, power consumption≤10uA, with the complexity of circuit, by the energy in accumulator farad capacitor C1, be transformed into output terminal by Switching Power Supply mode.

Described rectifying and voltage-stabilizing filtering output unit comprises the diode bridge rectifier circuit and connected voltage regulation filtering output circuit that are made up of NMOS tube Q3, NMOS tube Q4, PMOS Q5 and PMOS Q6.Here rectification circuit adopts unconventional diode bridge rectifier circuit, and under solving low input current, diode exists up to 0.7V pressure drop, and due to diode is nonlinear device, causes non-linear effects equally to loop current.

When there being electric current to flow through in loop, PMOS Q2, NMOS tube Q7 and NMOS tube Q1, PMOS Q8 alternate conduction, be converted to direct current, through the voltage stabilizing of 3.3v limit volt stabilivolt D1 limit volt, accumulator farad capacitor C1 is charged, stabilivolt U2 work output 2.0V reference voltage, through resistance R5, R6 dividing potential drop 1.0V is to comparer U1 reverse input end-IN, time accumulator farad capacitor C1 terminal voltage is charged to 3.3V, through resistance R1, positive input+IN the voltage of R4 dividing potential drop input comparator U1 is greater than reverse input end reference voltage, comparer U1 input high level, metal-oxide-semiconductor Q9, Q10 conducting, after resistance R7 and R6 parallel connection, dividing potential drop reduces the reverse input voltage of input comparator U1, output high level can both be stablized before keeping comparer U1 when accumulator farad capacitor C1 terminal voltage is reduced to 1.6V, keep NMOS tube Q9, the nmos switch pipe constant conduction of Q10 composition, NMOS tube Q10 conducting rear end isolation DC power work, electric capacity C3, resistance R8 and transformer T1 (p7-p8) combination concussion, be transformed into output port, Rectified alternating current is transformed to through NMOS tube Q3, PMOS Q6 and NMOS tube Q4, PMOS Q5 alternation, a stable DC voltage is exported through diode D3, D4 voltage stabilizing.

Energy collecting device solve current existing Switching Power Supply be all in the form of voltage and quiescent dissipation all at least a few more than mA, the problem of loop current only in tens uA low current ac current source loop circuits cannot be applied to.

Claims (9)

1. the system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT, it is characterized in that: the device comprising energy collecting device and measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT, described energy collecting device comprises the limit volt rectification unit connected successively, energy collection unit, low-power consumption DC isolating converter unit, rectifying and voltage-stabilizing filtering output unit and with limit lie prostrate rectification unit, energy collection unit, the low power consumption comparator control module that low-power consumption DC isolating converter unit is connected, described limit volt rectification unit is directly connected in tested loop, when having electric current to flow through in tested loop, be converted to DC voltage form through limit volt rectification unit to charge to energy collection unit, energy collection unit adopts capacitive way stored energy, the described energy function utilizing energy collecting device to collect based on the device of the relatively accurate current in resistance property measurement of the positive inverse transformation of Fourier FFT, comprise accurate AGC amplifier, low-pass filter, accurate zero-crossing comparator, time-delay trigger, ADC triggers sampling unit, sampling initial phase angle control module, MCU controller, described accurate AGC amplifier, low-pass filter, ADC triggers sampling unit and MCU controller connects successively, accurate AGC amplifier is also connected with MCU controller, described accurate zero-crossing comparator connects low-pass filter, ADC triggers sampling unit, time-delay trigger and MCU controller, described time-delay trigger is also connected with ADC and triggers sampling unit and MCU controller, described sampling initial phase angle control module is connected with MCU controller.

2. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 1, it is characterized in that: described accurate AGC amplifier is used for amplification input signal, described low-pass filter plays filter action for realizing to the input signal in the accurate AGC amplifier of the process of more than 1KHz, after filtering process, accurate zero-crossing comparator is sent on one tunnel, one tunnel send ADC triggering collection unit etc. to be collected, described accurate zero-crossing comparator is used for forward signal zero crossing being detected when it, namely a rising edge signal is exported, one tunnel is to time-delay trigger, one tunnel realizes the frequency Real-Time Monitoring to input signal to MCU controller, described time-delay trigger triggers ADC triggering collection unit after being used for the rising edge signal time delay setting value exported according to accurate zero-crossing comparator, described ADC triggering collection unit does not work under normal circumstances, when time-delay trigger is to an ADC triggering collection unit signal, ADC triggering collection unit brings into operation ADC collecting work, described ADC trigger collection element circuit coordinates MCU controller to the discrete acquisitions of input signal, after completing sampled point number, by realizing the analyzing and processing to sampled signal based on the relatively accurate current in resistance property measuring method of the positive inverse transformation of Fourier FFT, obtain total current and current in resistance property.

3. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 1, it is characterized in that: described sampling initial phase angle control module is used in the inaccurate situation of current in resistance property measured, realize the adjustment to the discrete sampling first-harmonic first phase angle in algorithm by the delay value of MUC controller adjustment time-delay trigger setting.

4. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 1, it is characterized in that: described energy collecting device comprises the limit volt rectification unit connected successively, energy collection unit, low-power consumption DC isolating converter unit, rectifying and voltage-stabilizing filtering output unit and with limit lie prostrate rectification unit, energy collection unit, the low power consumption comparator control module that low-power consumption DC isolating converter unit is connected, described limit volt rectification unit is directly connected in tested loop, when having electric current to flow through in tested loop, be converted to DC voltage form through limit volt rectification unit to charge to energy collection unit, energy collection unit adopts capacitive way stored energy.

5. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 4, it is characterized in that: described limit volt rectification unit is located in the series circuit of lightning arrester Leakage Current, comprise low loss capacitance C6, TVS pipe V1, NMOS tube Q1, PMOS Q2, NMOS tube Q7 and PMOS Q8, described low loss capacitance C6 and TVS pipe V1 are in parallel and be located between the first input end (J1) of lightning arrester Leakage Current and the second input end (J2), the drain electrode of described NMOS tube Q1 and first input end (J1), the grid of NMOS tube Q7 and PMOS Q8 is connected, the grid of NMOS tube Q1 is connected with the grid of the drain electrode of NMOS tube Q7 and PMOS Q2, the source electrode of NMOS tube Q1 is connected in energy collection unit and is connected with the source electrode of NMOS tube Q7, the drain electrode of described NMOS tube Q7 is connected to the second input end (J2), and its grid is also connected with the grid of PMOS Q8, the source electrode of described PMOS Q2 is connected with the source electrode of PMOS Q8, and is connected to energy collection unit, and the grid of PMOS Q2 is connected with the drain electrode of NMOS tube Q7 and PMOS Q8.

6. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 5, it is characterized in that: described energy collection unit comprises 3.3v limit volt stabilivolt D1 and energy storage farad capacitor C1, described 3.3v limit volt stabilivolt D1 and energy storage farad capacitor C1 is connected in PMOS Q2, the source electrode of PMOS Q8 and NMOS tube Q1, between the source electrode of NMOS tube Q7, wherein, the positive pole of 3.3v limit volt stabilivolt D1 and NMOS tube Q1, the source electrode of NMOS tube Q7 connects, the negative pole of 3.3v limit volt stabilivolt D1 and PMOS Q2, the source electrode of PMOS Q8 connects.

7. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 6, it is characterized in that: described low power consumption comparator control module comprises comparer U1, voltage stabilizer U2, nmos switch pipe and resistance R1, R2, R3, R4, R5, R6, R7, first input end and the 3.3v of described voltage stabilizer U2 limit the positive pole lying prostrate stabilivolt D1 to be connected, second input end is through resistance R5, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to connect, the output terminal of voltage stabilizer U2 limits the negative pole of volt stabilivolt D1 to be connected through resistance R2 and 3.3v, described comparer U1 positive input+IN limits the negative pole of volt stabilivolt D1 to connect through resistance R1 and 3.3v, the positive pole of volt stabilivolt D1 is limit to connect through resistance R4 and 3.3v, comparer U1 reverse input end-IN limits the positive pole of volt stabilivolt D1 to connect through resistance R6 and 3.3v, power input V+ and the 3.3v of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected, the output end vo ut of comparer U1 limits the negative pole of volt stabilivolt D1 to be connected through resistance R3 and 3.3v, Voltage Reference basic point GND and the 3.3v of comparer U1 limits the positive pole of volt stabilivolt D1 to connect, described nmos switch pipe comprises NMOS tube Q9, NMOS tube Q10, the drain electrode of described NMOS tube Q9 is connected with comparer U1 reverse input end-IN through resistance R7, through resistance R7, resistance R6 and 3.3v limits the positive pole of volt stabilivolt D1 to be connected, NMOS tube Q9, the source electrode of NMOS tube Q10 all limits the positive pole lying prostrate stabilivolt D1 to be connected with 3.3v, the grid of NMOS tube Q9 is connected with the grid of NMOS tube Q10 and limits the negative pole lying prostrate stabilivolt D1 to be connected through resistance R3 and 3.3v.

8. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 7, it is characterized in that: described low-power consumption DC isolating converter unit comprises transformer T1, electric capacity C3, C2, C4, diode D2, D5, PMOS Q11, electric capacity C2 and diode D2 is serially connected with between inductance L 1 two ends in described transformer T1 primary coil, in described transformer T1 primary coil, the p8 end of inductance L 2 connects the drain electrode of NMOS tube Q10 through diode D5, in described transformer T1 primary coil, the p7 end of inductance L 2 connects the grid of PMOS Q11 through electric capacity C3, the source electrode of PMOS Q11 connects the drain electrode of NMOS tube Q10, the p7 end of inductance L 2 is through electric capacity C3, resistance R8 connects the drain electrode of NMOS tube Q10, electric capacity C4 is serially connected with between inductance L 3 two ends in transformer T1 secondary coil.

9. a kind of system utilizing circuit energy to measure based on the relatively accurate current in resistance property of the positive inverse transformation of Fourier FFT according to claim 8, is characterized in that: described rectifying and voltage-stabilizing filtering output unit comprises the diode bridge rectifier circuit and connected voltage regulation filtering output circuit that are made up of NMOS tube Q3, NMOS tube Q4, PMOS Q5 and PMOS Q6.