CN103744469B - Multi-peak maximum power point tracking method of photovoltaic inverter - Google Patents
Multi-peak maximum power point tracking method of photovoltaic inverter Download PDFInfo
- Publication number
- CN103744469B CN103744469B CN201410033831.9A CN201410033831A CN103744469B CN 103744469 B CN103744469 B CN 103744469B CN 201410033831 A CN201410033831 A CN 201410033831A CN 103744469 B CN103744469 B CN 103744469B
- Authority
- CN
- China
- Prior art keywords
- scanning
- voltage
- power point
- constant power
- maximum power
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
- Y02E10/56—Power conversion systems, e.g. maximum power point trackers
Abstract
The invention discloses a multi-peak maximum power point tracking method of a photovoltaic inverter. Coarse scanning and fine scanning are performed alternately during a scanning step, the coarse scanning determines the local areas of crests, the fine scanning determines the local maximum power points in the local areas of the crests, the maximum power points of the whole P-V curve are found from the local maximum power points, and maximum power points tracking is achieved. The scanning step further comprises a scanning initializing step which determines the scanning range, the known areas, the minimum power judging points and the scanning directions. The method has the advantages that scanning time is reduced greatly by setting the scanning range, the known areas and the minimum power judging points, and excessive large voltage fluctuation caused by scanning is reduced by setting the scanning directions; maximum power point tracking is achieved accurately through the coarse scanning and the fine scanning, and voltage fluctuation is reduced by the coarse scanning and the fine scanning which are performed alternately.
Description
Technical field
The present invention relates to photovoltaic DC-to-AC converter technical field, particularly a kind of multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter.
Background technology
Because the solar panel in photovoltaic DC-to-AC converter exists I-V(current-voltage as shown in Fig. 1 (a)) curve characteristic, cause its P-V(power vs. voltage) output characteristic curve is epirelief parabolic shape, as shown in Fig. 1 (b).According to the characteristic of P-V curve, photovoltaic DC-to-AC converter needs the DC reference voltage constantly regulating self, makes stable output power on the top of P-V curve, i.e. maximum power point (MPP) place, guarantee its there is higher inversion efficiency.Namely maximum power point tracking (MPPT) is called by the method regulating DC reference voltage to obtain more multi output power.
Power due to the solar panel of monolithic is too small and output voltage only has tens volts, and photovoltaic DC-to-AC converter be all often by kilowatt in units of output power, grid-connected voltage is also far above the output voltage of monoblock battery plate, therefore, in actual applications, cell panel all provides direct current in the mode organizing string.Under the pattern of cell panel formation group string array, if during normal power generation, there is local shades and block that (as cloud, dust), cell panel parameter are inconsistent, cell panel temperature rise not square one each other in panel array, the P-V curve of cell panel then can be caused not overlap, thus cause the overall P-V curve of cell plate group string to present the form of multi-peak, as shown in Figure 2.
Traditional MPPT, be the voltage by constantly comparing front and back point and power, the direction come gradually to optimum is close, until be stabilized in a peak point place.But, under the P-V curve condition occurring multi-peak, traditional MPPT only can find from open-circuit voltage place (i.e. the low order end of P-V curve), after finding first peak point (the D point in Fig. 2), just no longer continue to find, but be stabilized in D point, thus fail to find real peak power point (real peak power point is at C point), cause certain power generation loss.
In order to solve traditional MPPT in the face of multi-peak situation time accurately can not find the problem of peak power point, someone proposes and first carries out P-V curve and scan comprehensively, analyzes each peak point position, then carries out conventional maximum power point tracking.Although the method can find out peak power point accurately, but still there are three defects: 1) P-V curve is scanned comprehensively, DC reference voltage will inevitably be made to be reduced to minimum point from the peak of MPPT voltage range, to cause output power to present larger fluctuation; 2) in order to ensure the accuracy scanned, scanning step need arrange less, then sweep time can be caused longer, if increase scanning step, easily occurs again the phenomenon of crossing over crest, causes scanning inaccurate; 3) scanning triggers and adopts timing scan more, and it is comparatively large that sweep frequency arranges difficulty, if scanning too frequently can cause power dissipation, the number of times of scanning may cause again accurately can not tracking maximum power point very little.
Summary of the invention
The object of the invention is to overcome the deficiency that maximum power point tracking is inaccurate, sweep time is long in prior art comprehensively existing for scanning, a kind of multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter is provided, when ensureing accurate tracking maximum power point, avoid voltage fluctuation large, reduce sweep time.A further object of the present invention scans under rational scanning triggering mode, accurately follows the trail of maximum power point.
In order to realize foregoing invention object, the invention provides following technical scheme:
A multi-peak maximum power point tracking method for photovoltaic DC-to-AC converter, comprise scanning step, described scanning step is:
Coarse scanning is carried out according to coarse scanning step-length, determine whether there is crest between adjacent two constant power points, if existed, close scanning is carried out according to close scanning step-length in regional area then between these adjacent two constant power points, mark the local maximum power point in this regional area, then continue to carry out coarse scanning according to aforesaid coarse scanning step-length and determine next local maximum power point; Intert through coarse scanning and close scanning and carry out, mark the local maximum power point in crest place regional areas all in sweep limit; The last maximum power point found out according to the local maximum power point in each regional area in whole sweep limit; Described constant power point is the intersection point of constant power straight line and P-V curve in sweep limit, and described constant power straight line is less than the power of current MPPT by performance number and the power points that both differ setting value forms.
Preferably, in said method, scanning initialization step was also comprised: according to ceiling voltage and the minimum voltage of the open-circuit voltage determination sweep limit of inverter before scanning step, and the voltage judging current MPPT respectively with the difference of ceiling voltage and minimum voltage, if the voltage of current MPPT and the difference of ceiling voltage are greater than the voltage of current MPPT and the difference of minimum voltage, then in scanning step from low-voltage to high voltage scanning direction, otherwise from high voltage to low-voltage scanning direction.The object of setting direction of scanning is to scan from the lower one end of voltage difference, to reduce voltage fluctuation during scanning.
Preferably, in said method, described sweep limit is 60% ~ 90% of the open-circuit voltage of photovoltaic DC-to-AC converter, and 60% of open-circuit voltage is the minimum voltage of sweep limit, and 90% of open-circuit voltage is the ceiling voltage of sweep limit.With 60% ~ 90% of open-circuit voltage for sweep limit, avoid and whole voltage range is scanned, greatly reduce sweep time.
Preferably, in said method, in scanning initialization step, also comprise step: according to the voltage of current MPPT, mark and the voltage regime of the voltage phase difference setting voltage value of current MPPT are Non-scanning mode region, local.Because the crest in Non-scanning mode region, local is known, not there is scanning meaning, when therefore scanning in sweep limit, do not scan, to reduce sweep time further for Non-scanning mode region, local.
Further, in said method, in scanning step, when carrying out coarse scanning, often move according to coarse scanning step-length and move a step, record voltage and the power of respective point in a P-V curve, and the intersection point marking P-V curve and constant power straight line is constant power point, often mark a constant power point, then judge whether there is crest between current constant power point and previous constant power point according to the derivative of constant power point and direction of scanning, if existed, carry out close scanning in the regional area between these two constant power points, otherwise proceed coarse scanning.
Further, in said method, the described derivative according to constant power point and direction of scanning judge that the method that whether there is crest between current constant power point and previous constant power point is: from low-voltage to high voltage scanning direction, if the derivative of previous constant power point is just, the derivative of current constant power point is negative, then there is crest between these adjacent two constant power points; From high voltage to low-voltage scanning direction, if the derivative of previous constant power point is negative, the derivative of current constant power point is just, then there is crest between these adjacent two constant power points.
Preferably, in above-mentioned steps, before scanning initialization step, also comprise scanning trigger determining step, described scanning triggers determination methods: judge that the cycle carries out an environmental temperature fluctuation and detects every an environment temperature, within an environment temperature judgement cycle, if environment temperature rises or decrease beyond design temperature undulating quantity, then trigger a multimodal scanning, otherwise not trigger sweep.
As another kind of embodiment, described scanning triggers determination methods: judge that the cycle carries out an output power and output current fluctuation detects every a power current, within a power current judgement cycle, if the output power of inverter rises or decrease beyond the power swing value of setting, and output current also rises or decrease beyond the current ripple level of setting, then trigger a multimodal scanning, otherwise not trigger sweep.
As another kind of embodiment, described scanning triggers determination methods: judge the temperature difference in inverter between panel array, if the temperature difference between adjacent two panel arrays exceedes the temperature value of setting, and adjacent twice sweep triggers Rule of judgment difference, then trigger a multimodal scanning, otherwise not trigger sweep.
compared with prior art, beneficial effect of the present invention:
The multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter of the present invention comprises scanning initialization step and scanning step, in scanning initialization step, by the setting of sweep limit, known region, lowest power judging point and direction of scanning, greatly reduce sweep time, improve scan efficiency.Coarse scanning stage and close scanning stage is comprised in scanning step, the coarse scanning stage determines whether regional area exists crest, the close scanning stage determines the local maximum power point existed in the regional area of crest, the last maximum power point finding out whole P-V curve from the local maximum power point in each regional area, realize peak power point tracking, the traditional MPPT of effective solution may find the shortcoming less than GMPP in multimodal situation; And coarse scanning and close scanning intert and carry out, return after regional area close scanning terminates and proceed coarse scanning, avoid voltage fluctuation excessive.
In addition, the inventive method adopts three kinds of scanning triggering judgment modes to carry out scanning and triggers judgement, the just trigger sweep when meeting trigger condition, avoid the drawback that traditional timing scan is brought, reduce the disturbance that scanning itself brings, shorten sweep time, improve the efficiency of scanning, indirectly improve the work efficiency of photovoltaic DC-to-AC converter.
Accompanying drawing illustrates:
Fig. 1 (a) is the current-voltage curve figure of monoblock battery plate in photovoltaic DC-to-AC converter; Fig. 1 (b) is the power vs. voltage curve figure of monoblock battery plate in photovoltaic DC-to-AC converter.
Fig. 2 is the power vs. voltage curve figure of cell plate group string in photovoltaic DC-to-AC converter.
Fig. 3 is the process flow diagram of maximum power point tracking method of the present invention.
Fig. 4 carries out multimodal in maximum power point tracking process for application the inventive method and scans schematic diagram.
Embodiment
Below in conjunction with test example and embodiment, the present invention is described in further detail.But this should be interpreted as that the scope of the above-mentioned theme of the present invention is only limitted to following embodiment, all technology realized based on content of the present invention all belong to scope of the present invention.
With reference to figure 3, Fig. 4, LMPP (Local Maximum Power Point) in Fig. 4 is local maximum power point, represent regional area maximum value position point in powertrace, namely regional area maximum value refer to the power maximal value in this regional area; GMPP(Global Maximum Power Point) be global maximum power point, represent in whole powertrace, the location point at maximum maximum value place.
The multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter of the present invention, comprise scanning initialization step and scanning step, wherein scanning step comprises again coarse scanning step and close scanning step.With reference to figure 3, concrete, the inventive method comprises the following steps:
S1: when multimodal scanning is triggered, judges whether to carry out scanning initialization, if not, enter S2, carry out scanning initialization procedure; If yes then enter S3, enter sweep phase.
S2: carry out scanning initialization, initialization procedure comprises the following steps:
S21: the voltage U and the power that record current MPPT, and according to the performance number determination lowest power judging point of current MPPT, at sweep phase, power does not carry out close scanning lower than the region of lowest power judging point.Simultaneously, mark is known region with the voltage regime of the voltage phase difference voltage U 0 of current MPPT, i.e. region [U-U0, U+U0] be labeled as known region, namely so-called known region refers to the crest in this region known (inverter operates in this place originally), therefore do not need to scan this region, therefore can be described as again Non-scanning mode region, local.
With reference to figure 4, there is minimum voltage distance (depending on cell panel quantity and physical characteristics factor) between two crests, two crests can not be occurred in this voltage distances length.Therefore mark known region, can skip known region scanning (known region not being scanned) during scanning, to reduce sweep time.Such as, supposing in Fig. 4 that B point position is 540V, C point position is 650V, and current MPPT is in C point crest location, and voltage U 0 value is 20V, and so known region is 630V ~ 670V, does not need to scan in 630V ~ 670V region during scanning.
S22: according to ceiling voltage and the minimum voltage of open-circuit voltage determination sweep limit, and the voltage judging current MPPT respectively with the difference of ceiling voltage and the difference of minimum voltage, the difference of the voltage of definition ceiling voltage and current MPPT is U1, the difference of the voltage and minimum voltage that define current MPPT is U2, if U1≤U2, then enter S23; Otherwise enter S24.
P-V curve presents multi-peak state and generally comes across the sunlight more sufficient time period (namely eliminate early morning and side evening), and within sunlight more sufficient time period, and the open-circuit voltage of cell panel compares determine, stable numerical value.According to the characteristic of multimodal P-V curve, GMPP be usually located at open-circuit voltage 60% ~ 90% between position, therefore, open-circuit voltage 60% ~ 90% scope interscan can reduce a large amount of sweep time, therefore the scope of 60% ~ 90% of open-circuit voltage is defined as sweep limit, 60% of open-circuit voltage is the minimum voltage of sweep limit, and 90% of open-circuit voltage is the ceiling voltage of sweep limit.Such as, cell panel open-circuit voltage is 800V, so sweep limit is 480V ~ 720V, that is to say in this voltage range, can carry out primary voltage scanning from low to high or from high to low, if (namely voltage from low to high) scanning from left to right, 720V is exactly end position, if turn left from the right side (namely voltage from high to low), 480V is exactly end position.The voltage supposing current MPPT is 650V, and due to 650V-480V>720V-650V, then multimodal scanning is from turning left in the right side, and 480V is exactly scan end position.The voltage span moving to 720V from 650V only has 70V, and has 170V from the voltage span that 650V moves to 480V, in order to reduce the fluctuation of voltage as much as possible, therefore chooses scanning of turning left from the right side.
S23: to turn left from the right side scanning (namely from high voltage to low-voltage scanning direction) at sweep phase, before scanning, first judge whether ceiling voltage position belongs to known region, if belonged to, scan start point is voltage location point residing for current MPPT, that is to say scanning from voltage location residing for current MPPT; If do not belonged to, scan start point is ceiling voltage position.Then sweep phase is entered.
S24: scan from left to right (namely from low-voltage to high voltage scanning direction) at sweep phase, before scanning, first judge whether minimum voltage position belongs to known region, if belonged to, scan start point is voltage location point residing for current MPPT, if do not belonged to, scans from minimum voltage position.Then sweep phase is entered.
In step S23 and S24, scan start point is determined further after determining direction of scanning, as previously mentioned, do not need to scan in the known region of voltage location residing for current MPPT, therefore judge that whether ceiling voltage and minimum voltage are at known region, if just do not scanned from ceiling voltage/minimum voltage at known region, reduce sweep time further.
Whether S3: before carrying out multimodal scanning, first judge current scanned, if scanned, then enter S4, enter the Information Statistics stage; If do not have scanned, then proceed scanning.Scanning process comprises coarse scanning and close scanning, concrete:
Under the coarse scanning stage, such as, carry out scanning according to coarse scanning step-length (namely coarse scanning step-length refers to larger step-length, 20V mono-step) mobile, and record voltage and the power information of each step scanning.In coarse scanning process, often move once, first judge to move the end position that whether can exceed sweep limit next time, if can end position be exceeded, then stop scanning next time, enter the Information Statistics stage; If can not end position be exceeded, continue mobile.Judge that the mobile method that whether can exceed the end position of sweep limit is that judge whether the distance of end position and current location is less than coarse scanning step-length, if distance is less than coarse scanning step-length, movement next time can exceed end position next time.Simultaneously in scanning moving process, judge lowest power judging point whether between the power of twice movement in front and back, if lowest power judging point is between the power of twice movement in front and back, then mark a constant power point, the voltage being constant power point with front and back two step average voltage.Determine that between every two constant power points be crest or trough according to the derivative of constant power point and direction of scanning.For direction of scanning for scan from left to right, the derivative of previous constant power point is just, the derivative of a rear constant power point is negative, is so crest between these adjacent two constant power points; Otherwise the derivative of previous constant power point is negative, the derivative of a rear constant power point is just, is so trough between these adjacent two constant power points.If be crest between current constant power point and previous constant power point, then with the ending point that this constant power point is close scanning region, previous constant power point is the starting point in close scanning region, enters the close scanning stage.If be trough between current constant power point and previous constant power point, then do not carry out close scanning, reduce sweep time further with this.
It should be noted that, the setting of coarse scanning step-length is quite important, if arrange too little meeting causes sweep time long, if arrange too large, can cause there is multiple crest and trough between two constant power points, and then cause MPPT trace location inaccurate.The setting of coarse scanning step-length is relevant with the physical parameter of cell panel, by emulation obtain P-V curve, to obtain suitable coarse scanning step-length, guarantee sweep time be unlikely to long while ensure only there is a crest or trough between two constant power points.
With reference to figure 4, to suppose in current P-V curve that A point power is 60W, B point be 140W, C point is 100W, and photovoltaic DC-to-AC converter is just running on C point place at present.If now multimodal triggers judgement and sends scanning application, require that inverter carries out multimodal scanning, in order to avoid unnecessary judgement, improve scan efficiency, inverter is according to current power (100W), down mark a constant power straight line (such as getting 80W), the power of this constant power straight line is lowest power judging point (80W is lowest power judging point), constant power straight line does not then carry out close scanning with lower area (namely power is lower than the region of lowest power judging point), because constant power straight line is necessarily very low with the power of lower area, even if there is crest to exist also not in all senses, as A point, there is no the meaning of close scanning.Therefore lowest power judging point is set, avoids too much sweep time.
With reference to figure 4, in the process of coarse scanning, the both sides up and down that two scanning sample points lay respectively at constant power straight line must be had, then (comprise this two scanning sample points) between these two scanning sample points and certainly exist a point, its power equals the power of constant power straight line, this point is defined as constant power point, that is to say that the intersection point of constant power straight line and P-V curve is defined as constant power point, and the voltage getting constant power point is the mean value of two scanning sample point voltages of the upper and lower both sides of constant power straight line.As shown in Figure 4, it is 20V that the voltage of two scanning sample points is respectively 480V and 500V(coarse scanning step-length), there is a constant power point (shown in figure No. 1 constant power point) between these two scanning sample points.Owing to there is not straight-line segment in P-V curve, therefore must there is a crest or trough between any two constant power points, then can judge that between two constant power points be crest or trough according to the derivative at constant power point place and direction of scanning.
Under the close scanning stage, carry out scanning according to close scanning step-length (i.e. less step-length, as 10V mono-step) mobile, and record voltage and the power information of each step.In a close scanning region, when scanning power peak, carrying out a LMPP mark, then exiting close scanning, get back to the position of coarse scanning stage final step, proceed coarse scanning.Crest place regional area is found out in coarse scanning, and close scanning is then the power points finding out crest place in this regional area.As shown in Figure 4, such as, carrying out coarse scanning from right to left, when scanning No. 3 power points, having found out No. 3 and No. 4 two constant power points, so judge to there is crest or trough between these two constant power points; Through judging to there is crest between these two constant power points, be then now retracted into No. 4 constant power points from current location (No. 3 constant power points) at once, carry out close scanning left; After verifying crest C, get back to current location at once again, continue to carry out coarse scanning left.If first carry out coarse scanning, after coarse scanning terminates, carry out close scanning again, voltage fluctuation so can be caused excessive.In the inventive method, coarse scanning and close scanning intert to be carried out, if scan certain regional area in coarse scanning process to there is crest, then enter the close scanning stage, find out the peak power point in this region, return again after this regional area close scanning terminates and proceed coarse scanning, avoid voltage fluctuation excessive with this.
S4: under the Information Statistics stage, compares all LMPP points of mark, draws prominent GMPP position in all LMPP points, namely completes to obtain the maximum power point tracking of multi-peak.
Adopt timing scan triggering mode, find suitable trigger rate, the maximum power point tracking method through above-mentioned multi-peak also can find out maximum power point comparatively accurately, faster.But it is comparatively large that sweep frequency arranges difficulty, if scanning too frequently can cause power dissipation, the number of times of scanning may cause again accurately can not tracking maximum power point very little.In addition, the basic reason of the appearance of multimodal P-V curve is caused to have three kinds: the intensity of illumination that cell panel receives each other inconsistent (shade, dirt problems); Certain temperature difference (caused by many factors, intensity of illumination is inconsistent also can cause temperature difference) is there is between cell plate group string; Cell panel physical parameter each other inconsistent (cell panel type difference causes).Because the reason causing the light intensity that receives between cell panel inconsistent is complicated and changeable), and some reason also approximate random (hot spot effect etc.) that temperature difference occurs, therefore, solve a random case with timing scan triggering mode a bit unreasonable.
Therefore, the scanning providing a kind of more science in the present embodiment triggers judgment mode, concrete, comprises step:
(1) judge whether current time is in the time period allowing to carry out multimodal scanning, if allowed, then enter step (2), if do not allowed, then refuse multimodal scanning and trigger.That is to say, judge that inverter is current and whether be in multimodal scan period, if inverter is current be in multimodal scan period, then stops scanning triggering and judge, only during inverter is in stable operation, just carry out trigger sweep judgement.
(2) judge that the cycle carries out an environmental temperature fluctuation and detects every an environment temperature, within an environment temperature judgement cycle, if environment temperature rises or decrease beyond design temperature undulating quantity, then trigger a multimodal scanning, otherwise not trigger sweep.After application multimodal is scanned, the initial time being with the time in this moment, with the environment temperature in this moment for initial temperature, enters next environment temperature and judges the cycle.Such as set environment temperature judges that the cycle is 30 minutes, and the undulating quantity of environment temperature is set as 3 DEG C.Time when bringing into operation with inverter is initial time (the 0th minute), with the environment temperature in initial time moment for initial temperature T0, supposes T0=25 DEG C.Then between the 0th minute to the 29th point and 59 seconds, if environment temperature is more than 28 DEG C (T0+ undulating quantity) or lower than 22 DEG C (T0-undulating quantitys), then apply for that a multimodal scanning triggers.If between the 0th minute to the 29th point and 59 seconds, environment temperature not more than 28 DEG C with lower than 22 DEG C, then, when full 30 minutes of timing, is new initial time with the time now, with the environment temperature in this moment for initial temperature, enters new one and takes turns the cycle.
Judge that the cycle carries out an output power and output current fluctuation detects every a power current, within a power current judgement cycle, if output power rises or decrease beyond the power swing value of setting, and output current also rises or decrease beyond the current ripple level of setting, then trigger a multimodal scanning, otherwise not trigger sweep.After application multimodal is scanned, the initial time being with the time in this moment, with the output current in this moment for initial current, the output power in this moment is initial power, enters next power current and judges the cycle.
Judge the temperature difference between panel array, if there is temperature difference between adjacent two panel arrays and temperature difference exceedes the temperature value of setting, and adjacent twice triggering Rule of judgment is identical, namely adjacent twice trigger condition is the temperature value that temperature difference between same Battery pack plate array exceedes setting, then do not trigger multimodal scanning; Trigger Rule of judgment twice if adjacent different, then trigger a multimodal scanning.Such as cell plate group string has 4 panel arrays in parallel, the temperature of each panel array one of them cell panel of stochastic sampling, then 4 panel arrays in parallel exist four temperature informations T1, T2, T3, T4.The temperature difference of getting trigger sweep is 10 DEG C (panel array situation is depended in the setting of this value).If there is temperature difference between adjacent two panel arrays, and temperature difference exceedes the temperature gap of setting, if T2 is 60 DEG C, T3 is 75 degrees Celsius, and last triggering is because differ more than 10 DEG C between T2 and T3, temperature difference then between this multimodal scanning triggering invalid (because it is identical to trigger reason twice, being all because the same Battery pack plate array of T2 and T3() is more than 10 DEG C).If last triggering is because all differ more than 10 DEG C between T1 and T2, T2 and T3, and this is because T2 and T3 differs 15 DEG C, then this triggers effectively.
It should be noted that, the three kinds of scannings provided in above-mentioned steps (2) are the relation of "or" between triggering and judging, meet wherein any one trigger condition and then trigger multimodal scanning.
As previously mentioned, the main cause causing the overall P-V curve of cell plate group string to present the form of multi-peak is that the intensity of illumination between cell panel is inconsistent, there is temperature difference, and cause intensity of illumination factor that is inconsistent, that there is temperature difference to be all random, therefore P-V curve presents multi-peak phenomenon and must not occur.If there is not multi-peak phenomenon the same day or only occurred a small amount of peak phenomenon often, if employing timing scan, multimodal scanning for several times is at least there is within one day, expend sweep time, cause inverter can not output energy as much as possible, and the situation that timing scan also may occur scanning and not scan, lose the meaning of scanning.And adopt trigger sweep mode, just carry out multimodal scanning when satisfied scanning trigger condition, avoid and expend unnecessary sweep time, decrease sweep time.Meanwhile, trigger sweep it also avoid and should to scan and situation about not scanning occurs.
All features disclosed in this instructions, or the step in disclosed all methods or process, except mutually exclusive feature and/or step, all can combine by any way.Arbitrary feature disclosed in this instructions (comprising any accessory claim, summary and accompanying drawing), unless specifically stated otherwise, all can be replaced by other equivalences or the alternative features with similar object.That is, unless specifically stated otherwise, each feature is an example in a series of equivalence or similar characteristics.
Claims (9)
1. a multi-peak maximum power point tracking method for photovoltaic DC-to-AC converter, comprise scanning step, it is characterized in that, described scanning step is:
Coarse scanning is carried out according to coarse scanning step-length, determine whether there is crest between adjacent two constant power points, if existed, close scanning is carried out according to close scanning step-length in regional area then between these adjacent two constant power points, mark the local maximum power point in this regional area, then continue to carry out coarse scanning according to aforesaid coarse scanning step-length and determine next local maximum power point; Intert through coarse scanning and close scanning and carry out, mark the local maximum power point in crest place regional areas all in sweep limit; The last maximum power point found out according to the local maximum power point in each regional area in whole sweep limit; Described constant power point is the intersection point of constant power straight line and P-V curve in sweep limit, and described constant power straight line is less than the power of current MPPT by performance number and the power points that both differ setting value forms.
2. the multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter according to claim 1, it is characterized in that, scanning initialization step was also comprised: according to ceiling voltage and the minimum voltage of the open-circuit voltage determination sweep limit of inverter before scanning step, and the voltage judging current MPPT respectively with the difference of ceiling voltage and the difference of minimum voltage, if the voltage of current MPPT and the difference of ceiling voltage are greater than the voltage of current MPPT and the difference of minimum voltage, then in scanning step from low-voltage to high voltage scanning direction, otherwise from high voltage to low-voltage scanning direction.
3. the multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter according to claim 2, it is characterized in that, described sweep limit is 60% ~ 90% of the open-circuit voltage of photovoltaic DC-to-AC converter, 60% of open-circuit voltage is the minimum voltage of sweep limit, and 90% of open-circuit voltage is the ceiling voltage of sweep limit.
4. the multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter according to claim 2, it is characterized in that, in described scanning initialization step, also comprise step: according to the voltage of current MPPT, mark and the voltage regime of the voltage phase difference setting voltage value of current MPPT are Non-scanning mode region, local.
5. the multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter according to claim 1, it is characterized in that, in described scanning step, when carrying out coarse scanning, often move according to coarse scanning step-length and move a step, record voltage and the power of respective point in a P-V curve, and the intersection point marking P-V curve and constant power straight line is constant power point, often mark a constant power point, then judge whether there is crest between current constant power point and previous constant power point according to the derivative of constant power point and direction of scanning, if existed, in the regional area between these two constant power points, carry out close scanning, otherwise proceed coarse scanning.
6. the multi-peak maximum power point tracking method of photovoltaic DC-to-AC converter according to claim 5, it is characterized in that, the described derivative according to constant power point and direction of scanning judge that the method that whether there is crest between current constant power point and previous constant power point is: from low-voltage to high voltage scanning direction, if the derivative of previous constant power point is just, the derivative of current constant power point is negative, then there is crest between these adjacent two constant power points; From high voltage to low-voltage scanning direction, if the derivative of previous constant power point is negative, the derivative of current constant power point is just, then there is crest between these adjacent two constant power points.
7. according to the multi-peak maximum power point tracking method of the photovoltaic DC-to-AC converter one of claim 2 to 6 Suo Shu, it is characterized in that, before scanning initialization step, also comprise scanning trigger determining step, described scanning triggers determining step: judge that the cycle carries out an environmental temperature fluctuation and detects every an environment temperature, within an environment temperature judgement cycle, if environment temperature rises or decrease beyond design temperature undulating quantity, then trigger a multimodal scanning, otherwise not trigger sweep.
8. according to the multi-peak maximum power point tracking method of the photovoltaic DC-to-AC converter one of claim 2 to 6 Suo Shu, it is characterized in that, before scanning initialization step, also comprise scanning trigger determining step, described scanning triggers determining step: judge that the cycle carries out an output power and output current fluctuation detects every a power current, within a power current judgement cycle, if the output power of inverter rises or decrease beyond the power swing value of setting, and output current also rises or decrease beyond the current ripple level of setting, then trigger a multimodal scanning, otherwise not trigger sweep.
9. according to the multi-peak maximum power point tracking method of the photovoltaic DC-to-AC converter one of claim 2 to 6 Suo Shu, it is characterized in that, before scanning initialization step, also comprise scanning trigger determining step, described scanning triggers determining step: judge the temperature difference in inverter between panel array, if the temperature difference between adjacent two panel arrays exceedes the temperature value of setting, and adjacent twice sweep trigger condition is different, then trigger a multimodal scanning, otherwise not trigger sweep.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410033831.9A CN103744469B (en) | 2014-01-24 | 2014-01-24 | Multi-peak maximum power point tracking method of photovoltaic inverter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201410033831.9A CN103744469B (en) | 2014-01-24 | 2014-01-24 | Multi-peak maximum power point tracking method of photovoltaic inverter |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103744469A CN103744469A (en) | 2014-04-23 |
| CN103744469B true CN103744469B (en) | 2015-03-18 |
Family
ID=50501496
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201410033831.9A Active CN103744469B (en) | 2014-01-24 | 2014-01-24 | Multi-peak maximum power point tracking method of photovoltaic inverter |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103744469B (en) |
Families Citing this family (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104362977B (en) * | 2014-11-06 | 2016-08-31 | 国家电网公司 | Bimodal dynamically/static MPP of a kind of photovoltaic DC-to-AC converter follows the tracks of Efficiency test method |
| CN104765402A (en) * | 2015-01-26 | 2015-07-08 | 闫朝阳 | Pendulum type MPPT (Maximum Power Point Tracking) algorithm of single-stage photovoltaic grid-connected inverter |
| CN104965559B (en) * | 2015-06-23 | 2017-01-25 | 四川蜀旺新能源股份有限公司 | Brand-new photovoltaic grid-connected inverter multi-wave-crest MPPT working method |
| CN106846436B (en) * | 2017-02-21 | 2020-09-04 | 中国计量大学 | Method for dividing multi-peak P-U curve of series photovoltaic module into regions |
| CN106774612B (en) * | 2017-03-01 | 2018-02-02 | 电子科技大学 | Photovoltaic maximum power tracking method based on gradient method extremum search under local shades |
| CN106680881A (en) * | 2017-03-01 | 2017-05-17 | 上海资誉电子科技有限公司 | Unmanned aerial vehicle detection system and method based on digital array |
| CN106919215A (en) * | 2017-03-29 | 2017-07-04 | 西交利物浦大学 | A kind of multi-peak maximum electric power tracking based on power increment method |
| CN108304026A (en) * | 2017-11-30 | 2018-07-20 | 深圳市首航新能源有限公司 | A kind of powerinjected method method |
| CN109885124A (en) * | 2019-03-11 | 2019-06-14 | 每天蓝(深圳)科技有限公司 | Maximum power point determines method, equipment and computer readable storage medium |
| TWI750714B (en) * | 2020-06-24 | 2021-12-21 | 亞源科技股份有限公司 | Method and system for dynamic maximum power point tracking |
| CN112329996B (en) * | 2020-10-26 | 2023-12-22 | 阳光智维科技股份有限公司 | Inverter mismatch optimization method, device and equipment |
| WO2022133791A1 (en) * | 2020-12-23 | 2022-06-30 | 华为数字能源技术有限公司 | Photovoltaic system and maximum input power determination method |
| CN113178894B (en) * | 2021-06-09 | 2024-04-12 | 阳光电源股份有限公司 | Photovoltaic inverter and MPP scanning control method thereof |
| CN113359940B (en) * | 2021-07-02 | 2022-05-17 | 吉林建筑大学 | Maximum power point tracking method and system of photovoltaic array |
| CN114995578A (en) * | 2022-04-28 | 2022-09-02 | 武汉大学 | Tracking method for maximum power of photovoltaic array under local shadow |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102495945A (en) * | 2011-11-11 | 2012-06-13 | 河海大学 | Valley delimitation searching method for tracking multi-peak maximum power point of photovoltaic power system |
| CN102624285A (en) * | 2012-03-23 | 2012-08-01 | 浙江工业大学 | Control method for maximum power point tracking (MPPT) of photovoltaic array |
| EP2624094A1 (en) * | 2012-01-31 | 2013-08-07 | ABB Oy | Method and arrangement in connection with photovoltaic power generator composed of series-connected photovoltaic modules |
| CN103365333A (en) * | 2012-03-31 | 2013-10-23 | 阳光电源股份有限公司 | MPPT (maximum power point tracking) scanning method for photovoltaic arrays |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2503427A1 (en) * | 2011-03-23 | 2012-09-26 | ABB Research Ltd. | Method for searching global maximum power point |
-
2014
- 2014-01-24 CN CN201410033831.9A patent/CN103744469B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102495945A (en) * | 2011-11-11 | 2012-06-13 | 河海大学 | Valley delimitation searching method for tracking multi-peak maximum power point of photovoltaic power system |
| EP2624094A1 (en) * | 2012-01-31 | 2013-08-07 | ABB Oy | Method and arrangement in connection with photovoltaic power generator composed of series-connected photovoltaic modules |
| CN102624285A (en) * | 2012-03-23 | 2012-08-01 | 浙江工业大学 | Control method for maximum power point tracking (MPPT) of photovoltaic array |
| CN103365333A (en) * | 2012-03-31 | 2013-10-23 | 阳光电源股份有限公司 | MPPT (maximum power point tracking) scanning method for photovoltaic arrays |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103744469A (en) | 2014-04-23 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103744469B (en) | Multi-peak maximum power point tracking method of photovoltaic inverter | |
| CN103955253B (en) | Based on the photovoltaic array multimodal value maximum power point tracing method of power closed loop scanning | |
| CN102594211B (en) | Optimizing method and tracking device for output power of partially shielded photovoltaic power generation system | |
| CN103677063B (en) | Based on knee point equal power method photovoltaic cell component maximum power tracking method and device | |
| JP5942183B2 (en) | Power conditioner for photovoltaic power generation | |
| CN102354247A (en) | Maximum power point tracking method, photovoltaic system controller and photovoltaic system | |
| CN103365333B (en) | MPPT (maximum power point tracking) scanning method for photovoltaic arrays | |
| Hua et al. | Modified perturb and observe MPPT with zero oscillation in steady-state for PV systems under partial shaded conditions | |
| CN107957743B (en) | A kind of photovoltaic maximum power point method for tracing | |
| CN104040453B (en) | Each unit group is performed to the photovoltaic generating system of MPPT maximum power point tracking | |
| Guerriero et al. | Accurate maximum power tracking in photovoltaic systems affected by partial shading | |
| CN105242740B (en) | Maximum power point tracking control method under partial shadow | |
| CN105207606A (en) | DMPPT photovoltaic power generation module based on time-sharing self-adaptive MCT algorithm | |
| CN102495945B (en) | Valley delimitation searching method for tracking multi-peak maximum power point of photovoltaic power system | |
| CN105867514A (en) | Method and system for multi-peak maximum power tracking of photovoltaic system | |
| KR101741924B1 (en) | Method for control hybrid MPPT to mitigate partial shading effects in photovoltaic arrays | |
| CN102608413A (en) | Method and device for detecting maximum power point of photovoltaic power generation | |
| Ortega et al. | New monitoring method to characterize individual modules in large photovoltaic systems | |
| CN106846436B (en) | Method for dividing multi-peak P-U curve of series photovoltaic module into regions | |
| CN108693914A (en) | NEW ADAPTIVE maximum power tracking and controlling method under a kind of local shades | |
| Vieira et al. | A high-performance stand-alone solar pv power system for led lighting | |
| CN108181966A (en) | A kind of photovoltaic MPPT control circuits and the photovoltaic multimodal MPP fast tracking methods based on voltage-power scan | |
| CN105159388B (en) | A kind of method of the MPPT maximum power point tracking in photovoltaic microgrid system | |
| CN104965559A (en) | Brand-new photovoltaic grid-connected inverter multi-wave-crest MPPT algorithm | |
| Newman et al. | Impact of dynamic Shading in cSi PV modules and systems for novel applications |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |