CN104280601A - Voltage measuring system of photovoltaic power source for intelligent vehicle monitoring - Google Patents

Abstract

The invention discloses a voltage measuring system of a photovoltaic power source for intelligent vehicle monitoring. The voltage measuring system comprises a network voltage collecting circuit which is arranged based on a photovoltaic grid-connected inverter controller system, eight standard network voltage effective value reference points, a network voltage effective value measuring module used for on-line measuring and a result judging and regulating module. The eight standard network voltage effective value reference points are established by an offline measurement standard sine input signal method, and every two adjacent points are connected. The result judging and regulating module is used for judging measuring results and conducting online correcting. The network voltage collecting circuit, the network voltage effective value measuring module and the result judging and regulating module are sequentially connected, and the eight standard network voltage effective value reference points are all connected with the result judging and regulating module. The voltage measuring system of the photovoltaic power source for the intelligent vehicle monitoring can overcome the defects that hardware cost is high, errors are large, and the detecting accuracy of network voltage effective values is low in the prior art, and achieve the advantages that the hardware cost is low, the errors are large, and the detecting accuracy of the network voltage effective values is high.

Description

A kind of voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply

Technical field

The present invention relates to technical field of intelligent traffic, particularly, relate to a kind of voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply.

Background technology

In the last few years; grid-connected technology obtains fast development; each national standard all strict regulations photovoltaic combining inverter needs to carry out overvoltage accurately and under-voltage protection function and low voltage ride-through function, and this just relates to how to carry out line voltage effective value measurement accurately.

Some photovoltaic DC-to-AC converter producers use special line voltage real effective chip to obtain line voltage effective value, the method concerning the line voltage of distortion to obtain the accuracy of line voltage effective value low, easily cause system malfunction, and hardware cost is relatively high.

In order to not increase hardware cost, most photovoltaic DC-to-AC converter producer all adopts voltage sensor and common operational amplifier, the composition such as resistance and electric capacity signal conditioning circuit, by analog to digital conversion (A/D) the sampled voltage instantaneous value of single-chip microcomputer or DSP, by algorithm calculating voltage effective value, thus carry out voltage protection, the method is without particular algorithm process, drift can be there is due to the operational amplifier in modulate circuit, temperature drift and resistance, the error of electric capacity causes the voltage A/D deviation true value of sampling, also there is noise signal interference simultaneously, thus cause calculate line voltage effective value inaccurate, thus impact protection voltage operation point, do not reach the requirement of national standard defined.

Therefore need to attempt to solve the inaccurate problem of line voltage RMS to DC from computing method.

In sum, realizing in process of the present invention, inventor finds at least to exist in prior art the defects such as hardware cost is high, error large and the accuracy of line voltage RMS to DC is low.

Summary of the invention

The object of the invention is to, for the problems referred to above, propose a kind of voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply, to realize the advantage that hardware cost is low, error is little and the accuracy of line voltage RMS to DC is high.

For achieving the above object, the technical solution used in the present invention is: (right to be copied is wanted)

The voltage measurement system of the Vehicular intelligent monitoring photo-voltaic power supply of various embodiments of the present invention, owing to comprising the vehicle information collecting device being arranged on prediction monitored area, peaceful harvester washed by this vehicle, and to adopt ups power to be main, photo-voltaic power supply and storage battery power supply be auxiliary power supply mode; Wherein, mate the voltage measurement system arranged with photo-voltaic power supply and comprise the line voltage Acquisition Circuit arranged based on photovoltaic parallel inverter control system, utilize off-line measurement standard sine input signal method establishment and 8 standard electrical network voltage effective value reference points of line between adjacent 2, on-line measurement electrical network voltage effective value measurement module, and for judging measurement result and the judgement of the result of on-line amending and conditioning module; Line voltage Acquisition Circuit, line voltage effective value measurement module and result judge and conditioning module is connected successively, and 8 standard electrical network voltage effective value reference points judge with result respectively and conditioning module is connected; Off-line measurement standard sine input signal can be adopted to obtain standard electrical network voltage effective value datum method, revise the line voltage effective value of on-line measurement; Thus the defect that hardware cost in prior art is high, error large and the accuracy of line voltage RMS to DC is low can be overcome, to realize the advantage that hardware cost is low, error is little and the accuracy of line voltage RMS to DC is high.

Other features and advantages of the present invention will be set forth in the following description, and, partly become apparent from instructions, or understand by implementing the present invention.

Below by drawings and Examples, technical scheme of the present invention is described in further detail.

Accompanying drawing explanation

Accompanying drawing is used to provide a further understanding of the present invention, and forms a part for instructions, together with embodiments of the present invention for explaining the present invention, is not construed as limiting the invention.In the accompanying drawings:

Fig. 1 is the interpolation curve schematic diagram containing standard line voltage effective value reference point during the input of off-line measurement standard sine signal in the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply of the present invention;

Fig. 2 is sampling period timer interrupt routine process flow diagram in the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply of the present invention;

Fig. 3 is the principle of work schematic diagram of the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply of the present invention.

By reference to the accompanying drawings, in the embodiment of the present invention, Reference numeral is as follows:

U-ordinate, represents input voltage effective value; Vs-horizontal ordinate, represents that single-chip microcomputer or DSP sampling calculate effective value; ULV2 represents line voltage effective value 2 on the low side; ULV1 represents line voltage effective value 1 on the low side; ULV represents the under-voltage effective value of the line voltage of national regulations; UN represents the electrical network rated voltage effective value of national regulations; UHV1 represents the higher effective value 1 of line voltage; UHV2 represents the higher effective value 2 of line voltage; UOV represents the line voltage overvoltage effective value of national regulations; Single-chip microcomputer when VSLV3 represents that input voltage effective value U is 0 or DSP sampling calculate effective value; Single-chip microcomputer when VSLV2 represents that input voltage effective value U is ULV2 or DSP sampling calculate effective value; Single-chip microcomputer when VSLV represents that input voltage effective value U is ULV or DSP sampling calculate effective value; Single-chip microcomputer when VSLV1 represents that input voltage effective value U is ULV1 or DSP sampling calculate effective value; Single-chip microcomputer when VSN represents that input voltage effective value U is UN or DSP sampling calculate effective value; Single-chip microcomputer when VSH1 represents that input voltage effective value U is UHV1 or DSP sampling calculate effective value; Single-chip microcomputer when VSH2 represents that input voltage effective value U is UHV2 or DSP sampling calculate effective value; Single-chip microcomputer when VSOV represents that input voltage effective value U is UOV or DSP sampling calculate effective value; A represents the reference point (VSLV3,0) during off-line measurement; B represents the reference point (VSLV2, ULV2) during off-line measurement; C represents the reference point (VSLV, ULV) during off-line measurement; D represents the reference point (VSLV1, ULV1) during off-line measurement; E represents the reference point (VSN, UN) during off-line measurement; F represents the reference point (VSHV1, UHV1) during off-line measurement; G represents the reference point (VSOV, UOV) during off-line measurement; H represents the reference point (VSHV2, UHV2) during off-line measurement; N represents that in half grid cycle, A/D changes sampling number.

Embodiment

Below in conjunction with accompanying drawing, the preferred embodiments of the present invention are described, should be appreciated that preferred embodiment described herein is only for instruction and explanation of the present invention, is not intended to limit the present invention.

According to the embodiment of the present invention, as shown in Figure 1, Figure 2 and Figure 3, a kind of voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply is provided.

The voltage measurement system of the Vehicular intelligent monitoring photo-voltaic power supply of the present embodiment, for the line voltage Acquisition Circuit of photovoltaic parallel inverter control system, first utilize off-line measurement standard sine input signal method establishment 8 standard electrical network voltage effective value reference points, then line between adjacent 2, thus the line voltage effective value interpolation equation set up between these 2, final online measures actual electric network voltage effective value, by judge that measured line voltage effective value size is in 8 standard electrical network voltage effective value reference points which between 2, line voltage effective value measured by revising according to interpolation equation between corresponding 2.

Photovoltaic parallel inverter control system can change sampling number N according to A/D in the line voltage frequency measured and half grid cycle, determines the sampling period, ensures that in half grid cycle, A/D conversion sampling number N is constant by sampling period Interruption.

Accurate measuring voltage has three steps as follows:

The first step, carries out single-phase mains voltage and measures preparation.By the different effective value (such as, 0 of standard sine wave generator modulating output, ULV2=20%UN, ULV1=90%UN, ULV=80%, UN=220V, UHV1=105%UN, UHV2=140%UN, UOV=110%UN) low-voltage signal that corresponding low-voltage signal replaces single-phase mains voltage to change through overvoltage sensor, makes it pass through by common operational amplifier, the composition such as resistance and electric capacity signal conditioning circuit, A/D conversion through single-chip microcomputer or DSP is sampled, kth voltage sample value u (k) is obtained through low-pass filtering algorithm (adopting typical finite impulse response filter to realize), utilize formula (1) and (2) to carry out the average voltage Uavg in half line voltage cycle and effective value Vs and calculate that (effective value that such as, reference point sampling calculates is respectively VSLV3, VSLV2, VSLV1, VLV, VSN, VSH1, VSH2, VSOV), store using the effective value of standard sine wave generator modulating output with through line voltage effective value a pair signal that single-chip microcomputer or DSP calculate as reference point.In like manner, by the low-voltage signal of the different voltage effective value of adjustment criteria sine wave signal generator modulating output, the effective value that can obtain 8 pairs of standard sine wave generator modulating output and the line voltage effective value signal calculated through single-chip microcomputer or DSP, above-mentioned 8 pairs of signals store (namely in Fig. 1 as reference point, A reference point (VSLV3, 0), B reference point (VSLV2, ULV2), C reference point (VSLV, ULV), D reference point (VSLV1, ULV1), E reference point (VSN, UN), F reference point (VSHV1, UHV1), G reference point (VSOV, UOV), H reference point (VSHV2, UHV2).This process completes 8 pairs of standard signal reference points required for single-phase mains voltage detection.

$U_{\mathrm{avg}}=\frac{1}{N}\underset{k=1}{\overset{N}{\mathrm{\Σ}}}u\left(k\right)---\left(1\right);$

$V_s=\frac{\mathrm{\π}}{2\sqrt{2}}{U}_{\mathrm{avg}}---\left(2\right).$

Second step, carries out single-phase mains voltage and really measures.Single-phase mains voltage is converted to low-voltage signal through overvoltage sensor, this low-voltage signal is through treatment step same as described above, namely first signal condition is carried out through signal conditioning circuit, secondly the A/D conversion through single-chip microcomputer or DSP is sampled, again through low-pass filtering algorithm (adopting typical finite impulse response filter to realize) filtering Voltage Harmonic component and noise, carry out average voltage and the effective value in half line voltage cycle of calculating according to formula (1) and (2).

3rd step, carries out line voltage effective value corrected Calculation.Utilize relevant two point interpolation formula (3), (4), (5), (6), (7), (8), (9) to revise calculated line voltage effective value Vs, thus draw for the protection of a voltage effective value U judged.Formula (3), (4), (5), (6), (7), (8), (9) are specific as follows:

$U=\frac{U_{\mathrm{LV}2}-0}{V_{\mathrm{sLV}2}-V_{\mathrm{sLV}3}}(V_s-V_{\mathrm{sLV}3}),$ Condition: V _sLV3≤ V _s< V _sLV2(3);

$U=\frac{U_{\mathrm{LV}}-U_{\mathrm{LV}2}}{V_{\mathrm{sLV}}-V_{\mathrm{sLV}2}}(V_s-V_{\mathrm{sLV}2})+U_{\mathrm{LV}2},$ Condition: V _sLV2≤ V _s< V _sLV(4);

$U=\frac{U_{\mathrm{LV}1}-U_{\mathrm{LV}}}{V_{\mathrm{sLV}1}-V_{\mathrm{sLV}}}(V_s-V_{\mathrm{sLV}})+U_{\mathrm{LV}},$ Condition: V _sLV≤ V _s< V _sLV1(5);

$U=\frac{U_N-U_{\mathrm{LV}1}}{V_{\mathrm{sN}}-V_{\mathrm{sLV}1}}(V_s-V_{\mathrm{sLV}1})+U_{\mathrm{LV}1},$ Condition: V _sLV1≤ V _s< V _sN(6);

$U=\frac{U_{\mathrm{HV}1}-U_N}{V_{\mathrm{sH}1}-V_{\mathrm{sN}}}(V_s-V_{\mathrm{sN}})+U_N,$ Condition: V _sN≤ V _s< V _sH1(7);

$U=\frac{U_{\mathrm{OV}}-U_{\mathrm{HV}1}}{V_{\mathrm{sOV}}-V_{\mathrm{sH}1}}(V_s-V_{\mathrm{sH}1})+U_{\mathrm{HV}1},$ Condition: V _sH1≤ V _s< V _sOV(8);

$U=\frac{U_{\mathrm{HV}2}-U_{\mathrm{OV}}}{V_{\mathrm{sH}2}-V_{\mathrm{sOV}}}(V_s-V_{\mathrm{sOV}})+U_{\mathrm{OV}},$ Condition: V _sOV≤ V _s< V _sH2(9).

Fig. 2 is sampling period timer interrupt routine process flow diagram.First carry out line voltage A/D sampling, then utilize low-pass filtering algorithm (adopting typical finite impulse response filter to realize) to carry out filtering to kth (0<k≤N) individual voltage sample value u (k).Then, judge whether to have carried out N sampling, if do not reach N time, then exit interrupt service routine; If reach N time, then residing interval judgement is carried out to calculated line voltage effective value Vs.Work as V _sLV3≤ V _s< V _sLV2time, utilize formula (3) obtain for the protection of voltage effective value U; Work as V _sLV2≤ V _s< V _sLVtime, utilize formula (4) obtain for the protection of voltage effective value U; Work as V _sLV≤ V _s< V _sLV1time, utilize formula (5) obtain for the protection of voltage effective value U; Work as V _sLV1≤ V _s< V _sNtime, utilize formula (6) obtain for the protection of voltage effective value U; Work as V _sN≤ V _s< V _sH1time, utilize formula (7) obtain for the protection of voltage effective value U; Work as V _sH1≤ V _s< V _sOVtime, utilize formula (8) obtain for the protection of voltage effective value U; Work as V _sOV≤ V _s< V _sH2time, utilize formula (9) obtain for the protection of voltage effective value U.After calculating terminates, exit interrupt service routine.

Technical scheme of the present invention; off-line measurement standard sine input signal is adopted to obtain standard electrical network voltage effective value datum method; revise the line voltage effective value of on-line measurement; overcome hardware modulate circuit and affect caused voltage A/D deviation true value problem by temperature, drift etc.; also the impact of filtering noise interference to a great extent; grid undervoltage and overvoltage protection accurately can be realized, there is good practical value.

In sum, the voltage measurement system of the Vehicular intelligent monitoring photo-voltaic power supply of the various embodiments described above of the present invention, the beneficial effect that at least can reach is: for the line voltage Acquisition Circuit of photovoltaic parallel inverter control system, disposable off-line measurement standard sine input signal is adopted to obtain standard electrical network voltage effective value datum method, revise the line voltage effective value of on-line measurement, thus there is drift in the operational amplifier overcome in modulate circuit, temperature drift and resistance, the error of electric capacity causes the voltage A/D deviation true value problem of sampling, also the impact of filtering noise interference to a great extent, realize grid undervoltage and overvoltage protection accurately.

Last it is noted that the foregoing is only the preferred embodiments of the present invention, be not limited to the present invention, although with reference to previous embodiment to invention has been detailed description, for a person skilled in the art, it still can be modified to the technical scheme described in foregoing embodiments, or carries out equivalent replacement to wherein portion of techniques feature.Within the spirit and principles in the present invention all, any amendment done, equivalent replacement, improvement etc., all should be included within protection scope of the present invention.

Claims (9)

1. the voltage measurement system of a Vehicular intelligent monitoring photo-voltaic power supply, it is characterized in that, comprise the vehicle information collecting device being arranged on prediction monitored area, peaceful harvester washed by this vehicle, and to adopt ups power to be main, photo-voltaic power supply and storage battery power supply be auxiliary power supply mode, wherein, mate the voltage measurement system arranged with photo-voltaic power supply and comprise the line voltage Acquisition Circuit arranged based on photovoltaic parallel inverter control system, utilize off-line measurement standard sine input signal method establishment, and 8 standard electrical network voltage effective value reference points of line between adjacent 2, for the line voltage effective value measurement module of on-line measurement actual electric network voltage effective value, and for judging which 2 standard electrical network voltage effective value reference point is line voltage effective value measurement module measure gained line voltage effective value in 8 standard electrical network voltage effective value reference points between, and result judgement and the conditioning module of gained line voltage effective value is measured according to interpolation equation correction between corresponding 2 standard electrical network voltage effective value reference points,

Described line voltage Acquisition Circuit, line voltage effective value measurement module judge with result and conditioning module is connected successively, and described 8 standard electrical network voltage effective value reference points judge with result respectively and conditioning module is connected.

2. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 1, is characterized in that, the course of work of described line voltage Acquisition Circuit, comprising:

Photovoltaic parallel inverter control system can change sampling number N according to A/D in the line voltage frequency measured and half grid cycle, determines the sampling period, ensures that in half grid cycle, A/D conversion sampling number N is constant by sampling period Interruption; N is natural number.

3. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 1 and 2, is characterized in that, described line voltage effective value measurement module carries out the process of voltage measurement, mainly comprises:

A, carry out single-phase mains voltage measure prepare;

B, carry out single-phase mains voltage and really measure;

C, carry out line voltage effective value corrected Calculation.

4. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 3, it is characterized in that, described step a specifically comprises:

The low-voltage signal replacing single-phase mains voltage to change through overvoltage sensor by the low-voltage signal that the different effective value of standard sine wave generator modulating output is corresponding, it is made to pass through primarily of operational amplifier, the signal conditioning circuit of resistance and electric capacity composition, A/D conversion through single-chip microcomputer or DSP is sampled, kth voltage sample value u (k) is obtained through low-pass filtering treatment, utilize formula (1) and (2) to carry out the average voltage Uavg in half line voltage cycle and effective value Vs to calculate, store using the effective value of standard sine wave generator modulating output with through line voltage effective value a pair signal that single-chip microcomputer or DSP calculate as reference point,

In like manner, by the low-voltage signal of the different voltage effective value of adjustment criteria sine wave signal generator modulating output, the effective value that can obtain 8 pairs of standard sine wave generator modulating output and the line voltage effective value signal calculated through single-chip microcomputer or DSP, above-mentioned 8 pairs of signals store as reference point, C reference point, D reference point, E reference point, F reference point, G reference point, H reference point;

Above process complete single-phase mains voltage detect required for 8 pairs of standard signal reference points, formula (1) and formula (2) specific as follows:

$U_{\mathrm{avg}}=\frac{1}{N}\underset{k=1}{\overset{N}{\mathrm{\&Sigma;}}}u\left(k\right)---\left(1\right);$

$V_s=\frac{\mathrm{\&pi;}}{2\sqrt{2}}{U}_{\mathrm{avg}}---\left(2\right).$

5. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 4, is characterized in that, the operation of described low-pass filtering treatment, specifically adopts finite impulse response filter to carry out low-pass filtering treatment.

6. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 4, it is characterized in that, described step b specifically comprises:

Single-phase mains voltage is converted to low-voltage signal through overvoltage sensor, and this low-voltage signal, through treatment step same as described above, namely first carries out signal condition through signal conditioning circuit;

Secondly the A/D conversion through single-chip microcomputer or DSP is sampled, then through low-pass filtering treatment filtering Voltage Harmonic component and noise, carries out average voltage and the effective value in half line voltage cycle of calculating according to formula (1) and (2).

7. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 6, it is characterized in that, described step c is specially:

Utilize relevant two point interpolation formula (3), (4), (5), (6), (7), (8), (9) to revise calculated line voltage effective value Vs, thus draw for the protection of a voltage effective value U judged; Formula (3), (4), (5), (6), (7), (8), (9) are specific as follows:

$U=\frac{U_{\mathrm{LV}2}-0}{V_{\mathrm{sLV}2}-V_{\mathrm{sLV}3}}(V_s-V_{\mathrm{sLV}3}),$ Condition: V _sLV3≤ V _s< V _sLV2(3);

$U=\frac{U_{\mathrm{LV}}-U_{\mathrm{LV}2}}{V_{\mathrm{sLV}}-V_{\mathrm{sLV}2}}(V_s-V_{\mathrm{sLV}2})+U_{\mathrm{LV}2},$ Condition: V _sLV2≤ V _s< V _sLV(4);

$U=\frac{U_{\mathrm{LV}1}-U_{\mathrm{LV}}}{V_{\mathrm{sLV}1}-V_{\mathrm{sLV}}}(V_s-V_{\mathrm{sLV}})+U_{\mathrm{LV}},$ Condition: V _sLV≤ V _s< V _sLV1(5);

$U=\frac{U_N-U_{\mathrm{LV}1}}{V_{\mathrm{sN}}-V_{\mathrm{sLV}1}}(V_s-V_{\mathrm{sLV}1})+U_{\mathrm{LV}1},$ Condition: V _sLV1≤ V _s< V _sN(6);

$U=\frac{U_{\mathrm{HV}1}-U_N}{V_{\mathrm{sH}1}-V_{\mathrm{sN}}}(V_s-V_{\mathrm{sN}})+U_N,$ Condition: V _sN≤ V _s< V _sH1(7);

$U=\frac{U_{\mathrm{OV}}-U_{\mathrm{HV}1}}{V_{\mathrm{sOV}}-V_{\mathrm{sH}1}}(V_s-V_{\mathrm{sH}1})+U_{\mathrm{HV}1},$ Condition: V _sH1≤ V _s< V _sOV(8);

$U=\frac{U_{\mathrm{HV}2}-U_{\mathrm{OV}}}{V_{\mathrm{sH}2}-V_{\mathrm{sOV}}}(V_s-V_{\mathrm{sOV}})+U_{\mathrm{OV}},$ Condition: V _sOV≤ V _s< V _sH2(9).

8. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 7, is characterized in that, in step c, also comprises the operation of sampling period Interruption.

9. the voltage measurement system of Vehicular intelligent monitoring photo-voltaic power supply according to claim 8, is characterized in that, the operation of described sampling period Interruption, specifically comprises:

First carry out line voltage A/D sampling, then utilize low-pass filtering treatment to carry out filtering to kth (0<k≤N) individual voltage sample value u (k);

Then, judge whether to have carried out N sampling, if do not reach N time, then exit interrupt service routine; If reach N time, then residing interval judgement is carried out to calculated line voltage effective value Vs;

Work as V _sLV3≤ V _s< V _sLV2time, utilize formula (3) obtain for the protection of voltage effective value U; Work as V _sLV2≤ V _s< V _sLVtime, utilize formula (4) obtain for the protection of voltage effective value U; Work as V _sLV≤ V _s< V _sLV1time, utilize formula (5) obtain for the protection of voltage effective value U; Work as V _sLV1≤ V _s< V _sNtime, utilize formula (6) obtain for the protection of voltage effective value U; Work as V _sN≤ V _s< V _sH1time, utilize formula (7) obtain for the protection of voltage effective value U; Work as V _sH1≤ V _s< V _sOVtime, utilize formula (8) obtain for the protection of voltage effective value U; Work as V _sOV≤ V _s< V _sH2time, utilize formula (9) obtain for the protection of voltage effective value U.