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CN-115756078-B - Maximum power point tracking control method and device based on improved disturbance observation method

CN115756078BCN 115756078 BCN115756078 BCN 115756078BCN-115756078-B

Abstract

The invention belongs to the technical field of new energy power generation, and particularly relates to a maximum power point tracking control method and device based on an improved disturbance observation method. The method comprises the steps of firstly obtaining input side average current I inavg , input side power P in , output side power P out and input side power increment delta P in of a photovoltaic inverter, and then controlling to increase a disturbance step by a first step U 1 if delta P in ＜-P in is carried out under the condition that I inavg ＜I max 、P out ＜P max and the maximum power point is not at a knee point position, and controlling to decrease the disturbance step by a second step U 2 if delta P in ≥-P in is carried out, wherein I max represents peak current, P max represents peak power, and U 2 ＞U 1 is carried out. According to the invention, the working state of the photovoltaic inverter is accurately judged, the step length is judged and searched, different step lengths are selected according to different conditions, so that the maximum power point tracking is performed, the tracking speed of the maximum power point is ensured, the tracking capability is more excellent, and the overall stability and reliability of the system are improved.

Inventors

  • GUO YANAN
  • LI WEILING
  • WANG HAIYAN
  • ZHU ZHIHAO
  • JIANG CHENGBO
  • WANG HONGQING
  • LI HONGGANG
  • WANG GUANRUI
  • XU ZIYAN
  • XU MINGHUI
  • LIU JUAN
  • YANG LONGWU

Assignees

  • 平高集团有限公司
  • 国网河南省电力公司平顶山供电公司

Dates

Publication Date
20260505
Application Date
20221206

Claims (8)

  1. 1. The maximum power point tracking control method based on the improved disturbance observation method is characterized by comprising the following steps of: Obtaining input side average current I inavg , input side power P in , output side power P out and input side power increment delta P in of the photovoltaic inverter; If the maximum power point is not at the knee point position in the condition of I inavg ＜I max 、P out ＜P max , controlling to increase the disturbance step by a first step U 1 if the delta P in ＜-P in is included, and controlling to decrease the disturbance step by a second step U 2 if the delta P in ≥-P in is included, wherein I max represents peak current, P max represents peak power, and U 2 ＞U 1 is included; If I inavg ＜I max 、P out ＜P max , the maximum power point is at the knee point position, Δp out ≥-P out , and Δp out ≤P out , the step increase number and the step decrease number are both set to 0, and then: In the case of ΔP in >0, control increases the disturbance step by a first step U 1 if ΔP out >0, otherwise control decreases the disturbance step by a first step U 1 , where ΔP out represents the output side power delta; If ΔP in is less than or equal to 0, control decreases the disturbance step by a first step U 1 if ΔP out >0, otherwise control increases the disturbance step by a first step U 1 .
  2. 2. The maximum power point tracking control method based on an improved disturbance observer according to claim 1, wherein in the case of I inavg ≥I max , the control increases the disturbance step by a first step U 1 .
  3. 3. The method of claim 1, wherein in the case of I inavg ＜I max 、P out ＜P max , where the maximum power point is at the knee point position, ΔP out ＜-P out , and ΔP in >0, if the number of step decreases is greater than the set number, then control decreases the disturbance step by a fourth step U 4 , otherwise control decreases the disturbance step by a third step U 3 , where ΔP out represents the output side power increment, U 4 ＞U 2 ＞U 3 ＞U 1 .
  4. 4. The method of claim 1, wherein if the number of step increases is equal to or greater than a set number, the control increases the disturbance step by a fourth step U 4 , and otherwise the control increases the disturbance step by a first step U 1 , wherein ΔP out represents an output side power increment, U 4 ＞U 2 .
  5. 5. The method of claim 1, wherein in the case of I inavg ＜I max 、P out ＜P max , where the maximum power point is at the knee point position, ΔP out ≥-P out 、ΔP out ＞P out , and ΔP in >0, if the number of step increases is equal to or greater than the set number, the control increases the disturbance step by a fourth step U 4 , otherwise the control increases the disturbance step by a third step U 3 , where ΔP out represents the output side power increment, U 4 ＞U 2 ＞U 3 ＞U 1 .
  6. 6. The method of claim 1, wherein if the step size is increased by a set number or more, the disturbance step size is controlled to be reduced by a fourth step size U 4 , and otherwise, the disturbance step size is controlled to be reduced by a third step size U 3 , wherein ΔP out represents an output side power increment U 4 ＞U 2 ＞U 3 ＞U 1 , in the case that I inavg ＜I max 、P out ＜P max is the knee point position, ΔP out ≥-P out 、ΔP out ＞P out is the maximum power point, and ΔP in is equal to or less than 0.
  7. 7. The method for controlling maximum power point tracking based on the improved disturbance observation method according to any one of claims 1 to 6, wherein the input side average current I inavg , the input side power P in , the output side power P out and the input side power increment Δp in are calculated by collecting an input side voltage U in , an input side current I in , an output side voltage U out and an output side current I out of the photovoltaic inverter.
  8. 8. A maximum power point tracking control device based on an improved disturbance observer method, comprising a memory and a processor for executing computer program instructions stored in the memory to implement the maximum power point tracking control method based on an improved disturbance observer method according to any one of claims 1 to 7.

Description

Maximum power point tracking control method and device based on improved disturbance observation method Technical Field The invention belongs to the technical field of new energy power generation, and particularly relates to a maximum power point tracking control method and device based on an improved disturbance observation method. Background Along with the proposal of carbon peak and carbon neutralization, the advantages of cleanness, environmental protection and high efficiency of the photovoltaic power generation show great application potential, but simultaneously, the voltage and the current output by the photovoltaic array show great nonlinearity due to the change of the external environment conditions, so that the maximum power point tracking (Maximum Power Point Tracking, MPPT) technology is indispensable in the photovoltaic array. Domestic and foreign scholars have proposed a number of Maximum Power Point Tracking (MPPT) algorithms, which can be classified into 3 classes. The first class is a general rule algorithm comprising a constant voltage tracking method and a short-circuit current method, wherein the algorithm is used for simply and regularly calculating the characteristics presented by a photovoltaic array, the tracking speed is high, the control is simple and easy to realize, but the accuracy and the stability are both to be improved, in the short-circuit current method, the measurement of short-circuit current is not easy to realize, and the second class is a self-adaptive control algorithm which is mainly provided for the present, and mainly comprises a control algorithm based on a fuzzy theory, a control algorithm based on an artificial neural network, a control algorithm based on a particle swarm algorithm and a control algorithm based on a genetic algorithm. The third type of algorithm is a self-optimizing algorithm and mainly comprises a disturbance observation method (perturbation and observe, P & Q) and a conductance increment method (INCREMENTAL CONDUCTANCE, INC), wherein the disturbance direction of voltage is determined by judging the continuous change trend of power, a small disturbance step length is applied near the maximum power point, and a larger disturbance step length is applied when the distance from the maximum power point is far, so that the maximum power point of the photovoltaic system is quickly reached. The conductivity increment method has good control effect and high stability, and when the external environment changes, the photovoltaic array can follow the change in a stable mode, but the algorithm is complex, so that the tracking time is long, and the requirement on hardware is high, so that the method is not commonly used. The disturbance observation method has simple algorithm and high tracking speed, but has poor stability compared with a conductivity increment method, most of the prior art adopts a disturbance observation method according to the input parameters of an inverter, the acquisition parameters are single, the step length is fixed, and the system oscillation and erroneous judgment are easy to occur. Disclosure of Invention The invention aims to provide a maximum power point tracking control method and device based on an improved disturbance observation method, which are used for solving the problem that a system is easy to oscillate and misjudge due to the fact that the disturbance observation method in the prior art is adopted for carrying out maximum power point tracking. In order to solve the technical problems, the invention provides a maximum power point tracking control method based on an improved disturbance observation method, which is used for obtaining an input side average current I inavg, an input side power P in, an output side power P out and an input side power increment delta P in of a photovoltaic inverter, wherein under the condition that I inavg＜Imax、Pout＜Pmax and a maximum power point are not at a knee point position, if delta P in＜-Pin is adopted, a disturbance step is controlled to be increased by a first step U 1, if delta P in≥-Pin is adopted, then the disturbance step is controlled to be reduced by a second step U 2, wherein I max represents peak current, P max represents peak power, and U 2＞U1 is controlled. The method has the advantages that the disturbance direction is judged through a plurality of parameters based on a disturbance observation method, the working state of the photovoltaic inverter is accurately judged through the parameters including the average current I inavg at the input side, the power P out at the output side, the power increment delta P in at the input side and the position of the maximum power point, the step length is judged and searched, different step lengths are selected according to different conditions, the maximum power point tracking is performed, the output efficiency of the photovoltaic array is improved, the tracking speed of the maximum power point is ensured, the tracking capabilit