CN116126086A - Maximum power point tracking control method and system and photovoltaic power generation output device - Google Patents
Maximum power point tracking control method and system and photovoltaic power generation output device Download PDFInfo
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- G05F1/00—Automatic systems in which deviations of an electric quantity from one or more predetermined values are detected at the output of the system and fed back to a device within the system to restore the detected quantity to its predetermined value or values, i.e. retroactive systems
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- 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 maximum power point tracking control method, a maximum power point tracking control system and a photovoltaic power generation output device, wherein the method comprises the following steps: obtaining an initial duty cycle for controlling the maximum power output of the photovoltaic array based on a disturbance observation method; the method further comprises a second method of: providing a cuckoo algorithm, wherein the bird nest position corresponds to the duty ratio of the power output of the photovoltaic array, and the health degree of the bird eggs corresponds to the output power of the photovoltaic array; obtaining a better bird nest position and the health degree of the bird eggs; judging whether the change rate of the health degree of the bird egg is larger than or equal to a threshold value, if so, returning to the first method, and if not, recording the position of the better bird nest corresponding to the health degree of the current bird egg as the optimal bird nest; the method combines the advantage of high tracking speed of the disturbance observation method with the advantage of strong global optimizing capability of the cuckoo algorithm, has more advantages in the tracking speed and accuracy of the maximum power point, and can effectively avoid larger fluctuation of the output power of the photovoltaic array.
Description
Technical Field
The invention relates to the technical field of photovoltaic power generation output control, in particular to a maximum power point tracking control method and system for photovoltaic power generation output and a photovoltaic power generation output device.
Background
Photovoltaic power generation is a research hot spot in the field of new energy power generation, but at present, photovoltaic cells are easily influenced by external environments such as illumination intensity and temperature, and cannot utilize solar power generation at maximum efficiency, so that the Maximum Power Point Tracking (MPPT) technology is particularly critical.
Under ideal conditions, the external environment is in a uniform illumination condition, the photovoltaic array P-U curve (namely the power/voltage curve) is in a unimodal state, and the maximum power point tracking can be realized by the conventional MPPT technology such as a disturbance observation method and a conductivity increment method, so that the method has wide application in a photovoltaic power generation system. However, under the actual working environment, the solar cell panel is shielded by dust, clouds, buildings and other external factors, and a local shadow appears, at this time, the power output curve of the photovoltaic cell has a plurality of peak points, and under this condition, the traditional MPPT technology and the improved variable step algorithm thereof are easy to fall into a local maximum power point. Therefore, the meta-heuristic algorithm is generally combined with other control algorithms to be applied to the MPPT technology under the complex illumination condition. However, the fuzzy rule setting of the fuzzy control method depends on human experience, and the design is difficult; the generalized regression neural network needs a large number of training samples, and has high space complexity; the searching capability of the traditional particle swarm algorithm depends on parameter selection to a great extent, and is easy to fall into a local optimal solution. Most intelligent optimization algorithms of groups, such as a cuckoo search algorithm, a gray wolf optimization algorithm and the like, are to be improved in global searching capacity, convergence speed and precision. Therefore, the existing control algorithm cannot solve the problems that the output power of the photovoltaic array is easy to fall into a local extremum, the adjusting speed is low and the fluctuation of the output power is large under the complex illumination condition.
Disclosure of Invention
The invention aims to provide a maximum power point tracking control method, a maximum power point tracking control system and a photovoltaic power generation output device, which can effectively overcome the defect that a photovoltaic array is easy to fall into a local extremum under a complex illumination condition and improve the adjustment speed and the output stability.
In order to achieve the above object, the present invention discloses a maximum power point tracking control method for photovoltaic power generation output, which includes a first method and a second method, the first method includes:
obtaining an initial duty ratio for controlling the maximum power output of a photovoltaic array based on a disturbance observation method, wherein the disturbance step length of the disturbance observation method changes along with the power variation of the output power of the photovoltaic array;
the second method comprises the following steps:
providing a cuckoo algorithm, wherein the bird nest position corresponds to the duty ratio of the power output of the photovoltaic array, the health degree of the bird eggs corresponds to the output power of the photovoltaic array, the upper limit of the bird nest position is built according to the working parameters of the photovoltaic array obtained by the disturbance observation method, and the initial duty ratio is built as the lower limit of the bird nest position;
obtaining a better bird nest position and the health degree of the bird eggs;
judging whether the change rate of the health degree of the bird egg is larger than or equal to a threshold value, if so, returning to the first method, and if not, recording the position of the better bird nest corresponding to the health degree of the bird egg as the optimal bird nest;
and outputting the duty ratio represented by the optimal bird nest to a power control circuit.
Preferably, in the cuckoo algorithm, after the optimal bird nest is obtained, whether the maximum distance between bird nests is smaller than a set threshold is further judged, if yes, the duty ratio represented by the optimal bird nest is output to a power control circuit, and if no, the bird nest position is updated through the Lewy flight.
Preferably, based on the cuckoo algorithm, the method for obtaining the preferred bird nest position and the health degree of the bird eggs comprises the following steps:
detecting and recording the first nest position and the health degree of the bird egg corresponding to the first nest position;
based on the Lewy flight, obtaining the next bird nest position and the corresponding bird egg health degree;
comparing the health degree of the bird egg at the current bird nest position with the health degree of the bird egg at the last bird nest position, and taking the bird nest position corresponding to the bird nest with larger value as the current bird nest position;
generating a random number r i ，0≤r i Judging whether the random number is less than or equal to 1 and judging whether the random number is greater than the probability of finding foreign bird eggs by a preset host bird, if so, continuously obtaining the next bird nest position to continuously update iteratively, and if not, recording the current bird nest position as a better birdNest position, and record the health of the bird egg corresponding to the preferred nest position.
Preferably, in the cuckoo algorithm, the upper and lower limits of the constructed bird nest position satisfy the following formula:
wherein D is + For the upper limit of the bird nest position, D - Is the lower limit of the nest position, D k For the initial duty cycle, I, tracked by the disturbance observer STC U is the maximum power point current of the photovoltaic array STC The maximum power point voltage of a single photovoltaic module in the photovoltaic array is I p R is the output current of the photovoltaic array L U is the load resistance of the output end of the photovoltaic array p K is the peak value number of the power/voltage curve of the output end of the photovoltaic array, and m is the lower limit voltage selection coefficient.
Preferably, the perturbation step S satisfies the following formula:
S＝ΔU max ×(1-Π -k|dP| )
wherein DeltaU max Pi is the maximum value of disturbance step length - And k is an adjusting parameter for controlling the change rate of the disturbance step length, and dP is the power change amount of the output power of the current photovoltaic array.
Preferably, the method for obtaining the initial duty ratio for controlling the maximum power output of the photovoltaic array based on the disturbance observation method comprises the following steps:
and measuring the current output power based on the disturbance observation method, calculating whether the change rate of the output power is smaller than a threshold value, if not, executing the measurement of the next output power according to the disturbance step length, and if so, outputting the duty ratio of the current control photovoltaic array power output to obtain the initial duty ratio.
Preferably, the optimizing method of the disturbance observation method comprises the following steps:
a. initializing an output voltage of the photovoltaic array;
b. detecting output voltage and output current of the output end of the photovoltaic array in real time to obtain current time voltage U (k) and current time current I (k), and voltage increment dU=dU (k) -U (k-1), power P (k) =U (k) I (k), and power increment dP=U (k) I (k) -U (k-1) I (k-1);
c. judging whether dP is equal to 0, if so, returning; if not, executing the step d;
d. judging whether dP is larger than 0, if so, executing the step e; if not, executing the step f;
e. judging whether dU is greater than 0, if so, making U (K+1) =U (K) +S, and returning; if not, let U (k+1) =u (K) -S, and return;
f. judging whether dU is larger than 0, if so, making U (K+1) =U (K) -S, and returning; if not, let U (k+1) =u (K) +s, and return;
wherein S is the disturbance step length.
The invention also discloses a photovoltaic power generation output device which comprises a voltage detector, a current detector, a maximum power point tracker, a PWM controller and a voltage converter;
the voltage converter is connected to the output end of the photovoltaic array, the output end of the voltage converter is used for being connected with a load, the output end of the PWM controller is connected with the voltage converter, the input end of the PWM controller is connected with the output end of the maximum power point tracker, the input end of the maximum power point tracker is also connected with the voltage detector and the current detector, the voltage detector is used for detecting the output voltage of the output end of the photovoltaic array, and the current detector is used for detecting the output current of the output end of the photovoltaic array; the maximum power point tracker works based on the maximum power point tracking control method for photovoltaic power generation output.
The invention also discloses a maximum power point tracking control system for photovoltaic power generation output, which comprises:
one or more processors;
a memory;
and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs including instructions for performing the maximum power point tracking control method for photovoltaic power generation output as described above.
The invention also discloses a computer readable storage medium comprising a computer program executable by a processor to perform the maximum power point tracking control method for photovoltaic power generation output as described above.
By the scheme, the advantage of high tracking speed of the disturbance observation method and the advantage of strong global optimizing capability of the cuckoo algorithm are combined, the method has more advantages in the tracking speed and accuracy of the maximum power point, the problem that the photovoltaic array falls into a local extremum under the complex illumination condition can be effectively solved, and the large fluctuation of the output power of the photovoltaic array can be effectively avoided.
Drawings
Fig. 1 is a schematic structural diagram of a photovoltaic power generation output device in an embodiment of the present invention.
FIG. 2 is a flow chart of a disturbance observation method according to an embodiment of the present invention.
Fig. 3 is a flowchart of a maximum power point tracking control method according to an embodiment of the present invention.
Detailed Description
In order to describe the technical content, the constructional features, the achieved objects and effects of the present invention in detail, the following description is made in connection with the embodiments and the accompanying drawings.
The embodiment discloses a photovoltaic power generation output device, which is used for charging a storage battery with maximum power output in real time by a photovoltaic array 10 in a photovoltaic power generation process. As shown in fig. 1, the photovoltaic power generation output apparatus includes a voltage detector 50, a current detector 60, a maximum power point tracker 20 (MPPT), a PWM controller 30, and a voltage converter 40 (DC/DC converter).
The voltage converter 40 is connected to the output end of the photovoltaic array 10, the output end of the voltage converter 40 is used for connecting with the load RL (i.e. the storage battery), the output end of the PWM controller 30 is connected to the voltage converter 40, and the input end of the PWM controller 30 is connected to the output end of the maximum power point tracker 20. The input terminal of the maximum power point tracker 20 is further connected to a voltage detector 50 and a current detector 60, the voltage detector 50 is used for detecting the output voltage of the output terminal of the photovoltaic array 10, and the current detector 60 is used for detecting the output current of the output terminal of the photovoltaic array 10 and feeding back the detected output voltage and output current to the maximum power point tracker 20. In this embodiment, the maximum power point tracker 20 outputs a corresponding duty ratio to the PWM controller 30 based on the maximum power point tracking control method, and the PWM controller 30 controls the operating state of the voltage converter 40 according to the received duty ratio, so as to load the load with the maximum power adapted to the current operating environment.
For the maximum power point tracker 20, in order to avoid trapping in a local extremum and to improve the control speed and stability, the maximum power point tracking method configured for the maximum power point tracker 20 in this embodiment includes a first method and a second method.
For the first method: it obtains an initial duty cycle that controls the maximum power output of the photovoltaic array 10 based on a disturbance observer (Perturb and Observe algorithms, P & O), wherein the disturbance step length of the disturbance observer varies with the amount of power variation of the output power of the photovoltaic array 10.
For the second method: it provides a Cuckoo Search (CS) algorithm in which the bird's nest position corresponds to the duty cycle of controlling the power output of the photovoltaic array 10, the health of the bird's eggs corresponds to the output power of the photovoltaic array 10, and the upper limit of the bird's nest position is constructed by using the operation parameters of the photovoltaic array 10 obtained by the disturbance observation method, and the initial duty cycle is constructed as the lower limit of the bird's nest position.
In this second method, the cuckoo algorithm works as follows:
firstly, obtaining a better bird nest position and the health degree of bird eggs;
then judging whether the change rate of the health degree of the bird egg is larger than or equal to a threshold value, if so, returning to the first method, and if not, recording the position of the better bird nest corresponding to the health degree of the current bird egg as the optimal bird nest;
the duty cycle represented by the optimal bird nest is output to the power control circuit (i.e., PWM controller 30).
Specifically, the change rate of the health of the bird egg (also the change rate of the output power of the photovoltaic place) delta P v The following formula one is satisfied.
Wherein P is (t) For the current output power, P (t-σ) The power is output before σs.
When the local shading or illumination intensity changes due to factors such as cloud, dust accumulation and building along with the change of the external environment, the output power of the photovoltaic array 10 also changes, and at this time, the disturbance observation method needs to be restarted to perform global maximum power search to reduce power loss, and the restarting discriminant is as follows:
ΔP v ≥ξ 0
wherein, xi 0 Is a power change rate threshold.
In the above embodiment, the advantage of fast tracking speed of the disturbance observation method and the advantage of strong global optimizing capability of the cuckoo algorithm are combined, so that the method has more advantages in tracking speed and accuracy of the maximum power point, the problem that the photovoltaic array 10 falls into a local extremum under a complex illumination condition can be effectively solved, and larger fluctuation of the output power of the photovoltaic array 10 can be effectively avoided.
Further, in the cuckoo algorithm, after the optimal bird nest is obtained, whether the maximum distance between bird nests is smaller than a set threshold value is also judged, if so, the termination condition of iterative operation is met, the duty ratio represented by the optimal bird nest is output to the power control circuit, and if not, the bird nest position is updated through Lewy flight.
Further, the method for obtaining the preferred bird nest position and the health degree of the bird eggs based on the cuckoo algorithm comprises the following steps:
detecting and recording the first nest position and the health degree of the bird egg corresponding to the first nest position;
based on the Lewy flight, obtaining the next bird nest position and the corresponding bird egg health degree;
comparing the health degree of the bird egg at the current bird nest position with the health degree of the bird egg at the last bird nest position, and taking the bird nest position corresponding to the bird nest with larger value as the current bird nest position;
generating a random number r i ，0≤r i Judging whether the random number is larger than the probability r of finding foreign bird eggs of a preset host bird or not, wherein the probability r is smaller than or equal to 1 a If yes, continuing to obtain the next bird nest position to continue iterative updating, if not, recording the current bird nest position as a better bird nest position, and recording the health degree of the bird eggs corresponding to the better bird nest position. Specifically, the discovery probability r a ＝0.25.
In this embodiment, a new set of bird nest positions X are obtained by Lewy flight (t) And with the nest position X generated in the last group (t-1) In contrast, a bird nest location with a better health (i.e., a greater output power) of a bird egg is used to replace a bird nest location with a worse health (i.e., a lesser output power) of a bird egg, and the health of the bird egg in the replaced bird nest location is updated. The Levin flight formula is shown as formula two.
Wherein t is the iteration number, α is a limiting coefficient of the flight step length, L is a random step length conforming to the Lewy distribution, γ is the flight dimension, β is a constant, in this embodiment β=3/2, x best For the currently preferred bird nest position, both u and v follow a uniform distribution.
After obtaining a new bird nest position by the Lewy flight formula, using a random number r i Probability r of finding foreign bird eggs with host bird a For comparison, if r i ＞r a And (3) replacing the bird nest position through the following formula III, and updating the health degree of the replaced bird eggs.
Wherein, the liquid crystal display device comprises a liquid crystal display device,
and->
Two bird nest locations in close proximity.
Further, in the cuckoo algorithm, the upper and lower limits of the constructed bird nest position satisfy the following formula four.
Wherein D is + For the upper limit of the bird nest position, D - Is the lower limit of the nest position, D k For initial duty cycle as tracked by disturbance observations, I STC U is the maximum power point current of the photovoltaic array 10 STC For the maximum power point voltage of a single photovoltaic module in the photovoltaic array 10, I p R is the output current of the photovoltaic array 10 L U is the load resistance of the output end of the photovoltaic array 10 p For the lower voltage limit, k is the number of peaks of the power/voltage curve at the output of the photovoltaic array 10 and m is the lower voltage limit selection factor.
Further, the disturbance step S satisfies the following formula five.
S＝ΔU max ×(1-Π -k|dP| ) (equation five)
Wherein DeltaU max Pi is the maximum value of disturbance step length - For the circumferential rate, k is an adjustment parameter for controlling the rate of change of the disturbance step, and dP is the power variation of the current output power of the photovoltaic array 10.
Therefore, the disturbance step value S is updated continuously along with the change of the working point, the disturbance step size can be quickly adjusted when the working point is close to or far from the maximum power point, the tracking precision is improved, and the output power is prevented from shaking greatly.
In another embodiment, a method for obtaining an initial duty cycle for controlling a maximum power output of a photovoltaic array 10 based on a disturbance observer method comprises:
measuring the current output power based on a variable step disturbance observation method, calculating whether the change rate of the output power is smaller than a threshold value, if not, executing the measurement of the next maximum output power according to the disturbance step, and if so, outputting the duty ratio of the power output of the current control photovoltaic array 10 to obtain an initial duty ratio D k 。
Specifically, as shown in fig. 2, the optimizing method of the disturbance observation method includes the following steps:
a. initializing the output voltage of the photovoltaic array 10, wherein in the embodiment, the initial output voltage is 70% -80% of the open-circuit voltage of the photovoltaic array 10;
b. detecting output voltage and output current of the output end of the photovoltaic array 10 in real time to obtain a current time voltage U (k) and a current time current I (k), and voltage increment dU=u (k) -U (k-1), power P (k) =u (k) ×i (k), and power increment dp=u (k) ×i (k) -U (k-1) ×i (k-1);
c. judging whether dP is equal to 0, if so, returning; if not, executing the step d;
d. judging whether dP is larger than 0, if so, executing the step e; if not, executing the step f;
e. judging whether dU is greater than 0, if so, making U (K+1) =U (K) +S, and returning; if not, let U (k+1) =u (K) -S, and return;
f. judging whether dU is larger than 0, if so, making U (K+1) =U (K) -S, and returning; if not, let U (k+1) =u (K) +s, and return;
wherein S is the disturbance step length.
In summary, the present invention discloses a photovoltaic power generation output device, in which an optimal duty ratio is sent to a PWM controller 30 through a maximum power point tracker 20, and the PWM controller 30 generates a PWM signal to control a transformer inverter, thereby realizing the maximum output power of a photovoltaic array 10. Specifically, as shown in fig. 3, the operation mode of the maximum power point tracker 20 includes the following steps:
s1: starting a disturbance observation method;
s2: measuring the current output power;
s3: judging not to beEquation ΔP v ＜ξ 0 If not, turning to step S1, and if so, turning to step S4;
s4: outputting the current duty cycle;
s5: starting a cuckoo algorithm, and obtaining the initial position of each bird nest;
s6: measuring the health of the bird eggs in the initial bird nest (i.e., the output power of the photovoltaic array 10);
s7: obtaining the next bird nest position through the Lewy flight;
s8: obtaining a better bird nest position through the discovery probability;
s9: measuring the health of the bird eggs in the preferred bird nest position;
s10: determining inequality ΔP v ≥ξ 0 If yes, turning to step S1, and if no, turning to step S11;
s11: recording the preferred bird nest position corresponding to the current bird egg health degree as the optimal bird nest;
s12: judging whether the maximum distance between bird nests is smaller than a set threshold, if not, turning to step S7, and if so, turning to step S13;
s13: the duty cycle represented by the optimal bird nest is output to PWM controller 30.
The working mode of the maximum power point tracker 20 adopts a mode of combining an improved disturbance observation method and a cuckoo algorithm to track the power point extremum at the output end of the photovoltaic array 10, so that the problem that the photovoltaic array 10 is easy to fall into a local extremum under a complex illumination condition is solved. Specifically, an initial duty cycle is obtained based on an improved disturbance observation method, and then a cuckoo algorithm constructs upper and lower limits of the bird nest position according to the initial duty cycle obtained by the disturbance observation method and the working parameters of the photovoltaic array 10, so that the voltage search range of the cuckoo algorithm is adjusted, and the maximum power point can be quickly and accurately tracked after the cuckoo algorithm is introduced in a later period. In addition, as the disturbance step length in the disturbance observation method changes along with the power variation of the output power of the photovoltaic array 10, the size of the disturbance step length can be quickly adjusted when the working point is close to or far from the maximum power point, the tracking accuracy is high, and the output power is prevented from shaking greatly.
The present invention also discloses another maximum power point tracking control system comprising one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for performing the maximum power point tracking control method as described above. The processor may be a general-purpose central processing unit (Central Processing Unit, CPU), microprocessor, application specific integrated circuit (Application Specific Integrated Circuit, ASIC), or one or more integrated circuits for executing related programs to implement the functions required to be performed by the modules in the maximum power point tracking control system of the embodiments of the present application or to perform the maximum power point tracking control method of the embodiments of the present application.
The present invention also discloses a computer readable storage medium comprising a computer program executable by a processor to perform the maximum power point tracking control method as described above. The computer readable storage medium may be any available medium that can be accessed by a computer or a data storage device such as a server, data center, etc. that contains an integration of one or more available media. The usable medium may be a read-only memory (ROM), or a random-access memory (random access memory, RAM), or a magnetic medium, for example, a floppy disk, a hard disk, a magnetic tape, a magnetic disk, or an optical medium, for example, a digital versatile disk (digital versatile disc, DVD), or a semiconductor medium, for example, a Solid State Disk (SSD), or the like.
The present application also discloses a computer program product or a computer program comprising computer instructions stored in a computer readable storage medium. The processor of the electronic device reads the computer instructions from the computer-readable storage medium, and the processor executes the computer instructions so that the electronic device performs the maximum power point tracking control method described above.
The foregoing description of the preferred embodiments of the present invention is not intended to limit the scope of the claims, which follow, as defined in the claims.
Claims (10)
1. A maximum power point tracking control method for photovoltaic power generation output, comprising a first method and a second method, the first method comprising:
obtaining an initial duty ratio for controlling the maximum power output of a photovoltaic array based on a disturbance observation method, wherein the disturbance step length of the disturbance observation method changes along with the power variation of the output power of the photovoltaic array;
the second method comprises the following steps:
providing a cuckoo algorithm, wherein the bird nest position corresponds to the duty ratio of the power output of the photovoltaic array, the health degree of the bird eggs corresponds to the output power of the photovoltaic array, the upper limit of the bird nest position is built according to the working parameters of the photovoltaic array obtained by the disturbance observation method, and the initial duty ratio is built as the lower limit of the bird nest position;
obtaining a better bird nest position and the health degree of the bird eggs;
judging whether the change rate of the health degree of the bird egg is larger than or equal to a threshold value, if so, returning to the first method, and if not, recording the position of the better bird nest corresponding to the health degree of the bird egg as the optimal bird nest;
and outputting the duty ratio represented by the optimal bird nest to a power control circuit.
2. The method according to claim 1, wherein in the cuckoo algorithm, when an optimal bird nest is obtained, it is further determined whether a maximum distance between bird nests is smaller than a set threshold, if so, a duty ratio represented by the optimal bird nest is output to a power control circuit, and if not, a bird nest position is updated by a lewy flight.
3. The method for tracking and controlling the maximum power point for photovoltaic power generation output according to claim 2, wherein the method for obtaining the preferred bird nest position and the health degree of the bird eggs based on the cuckoo algorithm comprises the following steps:
detecting and recording the first nest position and the health degree of the bird egg corresponding to the first nest position;
based on the Lewy flight, obtaining the next bird nest position and the corresponding bird egg health degree;
comparing the health degree of the bird egg at the current bird nest position with the health degree of the bird egg at the last bird nest position, and taking the bird nest position corresponding to the bird nest with larger value as the current bird nest position;
generating a random number r i ，0≤r i And (3) judging whether the random number is larger than the probability of finding the external bird eggs by the preset host birds or not, if so, continuing to acquire the next bird nest position so as to continue iterative updating, if not, recording the current bird nest position as a better bird nest position, and recording the health degree of the bird eggs corresponding to the better bird nest position.
4. The maximum power point tracking control method for photovoltaic power generation output according to claim 1, wherein in the cuckoo algorithm, upper and lower limits of the constructed bird nest position satisfy the following formula:
wherein D is + For the upper limit of the bird nest position, D - Is the lower limit of the nest position, D k For the initial duty cycle, I, tracked by the disturbance observer STC U is the maximum power point current of the photovoltaic array STC The maximum power point voltage of a single photovoltaic module in the photovoltaic array is I p R is the output current of the photovoltaic array L U is the load resistance of the output end of the photovoltaic array p K is the peak value number of the power/voltage curve of the output end of the photovoltaic array, and m is the lower limit voltage selection coefficient.
5. The maximum power point tracking control method for photovoltaic power generation output according to claim 1, characterized in that the disturbance step S satisfies the following formula:
S＝ΔU max ×(1-Π -kdP )
wherein DeltaU max Pi is the maximum value of disturbance step length - And k is an adjusting parameter for controlling the change rate of the disturbance step length, and dP is the power change amount of the output power of the current photovoltaic array.
6. The method for maximum power point tracking control for photovoltaic power generation output according to claim 1, wherein the method for obtaining an initial duty cycle for controlling the maximum power output of the photovoltaic array based on the disturbance observation method comprises:
and measuring the current output power based on the disturbance observation method, calculating whether the change rate of the output power is smaller than a threshold value, if not, executing the measurement of the next output power according to the disturbance step length, and if so, outputting the duty ratio of the current control photovoltaic array power output to obtain the initial duty ratio.
7. The maximum power point tracking control method for photovoltaic power generation output according to claim 6, characterized in that the optimizing method of the disturbance observation method comprises the steps of:
a. initializing an output voltage of the photovoltaic array;
b. detecting output voltage and output current of the output end of the photovoltaic array in real time to obtain current time voltage U (k) and current time current I (k), and voltage increment dU=dU (k) -U (k-1), power P (k) =U (k) I (k), and power increment dP=U (k) I (k) -U (k-1) I (k-1);
c. judging whether dP is equal to 0, if so, returning; if not, executing the step d;
d. judging whether dP is larger than 0, if so, executing the step e; if not, executing the step f;
e. judging whether dU is greater than 0, if so, making U (K+1) =U (K) +S, and returning; if not, let U (k+1) =u (K) -S, and return;
f. judging whether dU is larger than 0, if so, making U (K+1) =U (K) -S, and returning; if not, let U (k+1) =u (K) +s, and return;
wherein S is the disturbance step length.
8. The photovoltaic power generation output device is characterized by comprising a voltage detector, a current detector, a maximum power point tracker, a PWM controller and a voltage converter;
the voltage converter is connected to the output end of the photovoltaic array, the output end of the voltage converter is used for being connected with a load, the output end of the PWM controller is connected with the voltage converter, the input end of the PWM controller is connected with the output end of the maximum power point tracker, the input end of the maximum power point tracker is also connected with the voltage detector and the current detector, the voltage detector is used for detecting the output voltage of the output end of the photovoltaic array, and the current detector is used for detecting the output current of the output end of the photovoltaic array; the maximum power point tracker operates based on the maximum power point tracking control method for photovoltaic power generation output according to any one of claims 1 to 7.
9. A maximum power point tracking control system for photovoltaic power generation output, comprising:
one or more processors;
a memory;
and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the programs comprising instructions for performing the maximum power point tracking control method for photovoltaic power generation output of any of claims 1 to 7.
10. A computer-readable storage medium, comprising a computer program executable by a processor to perform the maximum power point tracking control method for photovoltaic power generation output as claimed in any one of claims 1 to 7.
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