CN104156029B

CN104156029B - MPPT control method based on disturbance self-adaption

Info

Publication number: CN104156029B
Application number: CN201410400774.3A
Authority: CN
Inventors: 孙攀; 陶保震; 袁博; 李立; 张少强
Original assignee: Nanjing Guodian Nanzi Rural Power Grid Automation Engineering Co Ltd
Current assignee: Guodian Nanjing Automation Co Ltd
Priority date: 2014-08-14
Filing date: 2014-08-14
Publication date: 2015-07-08
Anticipated expiration: 2034-08-14
Also published as: CN104156029A

Abstract

The invention discloses an MPPT control method based on disturbance self-adaption. The method includes the steps of firstly, collecting the port voltage U(k) and the port current I(k), calculating the real-time power P(k), comparing the real-time power P(k) with the theoretical maximum power of a cell panel, and starting the maximum power control; exerting the initial disturbance quantity dU on the port voltage U(k), collecting the real-time port voltage data U(k+1)=U+dU and the real-time port current data I(k+1) produced after the photovoltaic cell panel is stabilized, calculating the power P(k+1), comparing the power P(k+1) with the power P(k+1)-P(k) produced before the disturbance quantity is exerted, if the result shows that power is increased, increasing the disturbance quantity dU+T when the disturbance is exerted next time, conducting execution repeatedly in this way till the result of comparison between the power produced before disturbance is exerted and the power produced after disturbance is exerted shows that the power is decreased, collecting the real-time port voltage U(y) of the photovoltaic cell panel, exerting reverse disturbance U(y)-dU, reducing the disturbance quantity dU-T when disturbance is exerted next time, and repeatedly exerting the second step when the power comparison result shows that the power changes; thirdly, finding the corresponding voltage value U(z) produced when the cell panel outputs the maximum power, and ending the control.

Description

A kind of based on the adaptive MPPT control method of disturbance

Technical field

The present invention relates to a kind of based on the adaptive MPPT control method of disturbance, in particular to a kind of control method realizing the maximum power output of stage type photovoltaic DC-to-AC converter, the photovoltaic energy being applicable to various power grade generates electricity by way of merging two or more grid systems occasion.The invention belongs to technical field of photovoltaic power generation.

Background technology

Generation of electricity by new energy has been admitted widely all over the world and has been developed, wherein photovoltaic generation especially new energy field development key player.Sun power is as a kind of inexhaustible green energy resource, and development photovoltaic generation is trend of the times by the present situation dealing with China's energy scarcity.As everyone knows, the core technology of photovoltaic generating system is that photovoltaic inversion is grid-connected, and it converts the direct current that solar panel produces in electrical network alternating current, under wherein key is how to allow photovoltaic battery panel always work in the condition of maximum efficiency utilization.

The topology of photovoltaic DC-to-AC converter common is at present two-stage type mostly, and the first order is DC-DC conversion, and the second level is DC-AC conversion.It is the output DC voltage raising photovoltaic battery panel that DC-DC converts its effect, completes the realization that MPPT controls simultaneously; It is as far as possible loss-free DC power to be reverse into be exchanged and realize grid-connected that DC-AC converts its effect.

MPPT maximum power tracking and controlling method be in fact one from searching process, namely by control end voltage or other physical quantitys, make photovoltaic cell can under various different sunshine and temperature conditions Maximum Power Output intelligently.Current existing MPPT maximum power tracking and controlling method has: increment conductive method, climbing method, fluctuation relevant control method, disturbance observation method etc.Tradition MPPT algorithm---disturbance observation, the search peak power spot speed caused because disturbance step-length is fixed is comparatively slow and occur the deficiency of larger oscillation at maximum power point.

Summary of the invention

Technical matters to be solved by this invention is the deficiency for improving traditional MPPT-disturbance observation, the search peak power spot speed caused because disturbance step-length is fixed is comparatively slow and occur the deficiency of larger oscillation at maximum power point, and the MPPT algorithm proposing a kind of disturbance adaptive step reaches good steady-state behaviour and dynamic property.

The technical solution used in the present invention is: a kind of based on the adaptive MPPT control method of disturbance, concrete steps are:

Step 1 is when photovoltaic battery panel is started working, port voltage U (k) and electric current I (k) are gathered, calculating realtime power P (k), when the theoretical peak power of itself and cell panel compares when there is difference, then starting maximum power control.

Step 2 applies an initial disturbance amount dU to port voltage U (k), ginseng collection photovoltaic battery panel stablize after real-time port voltage data U (k+1)=U+dU and current data I (k+1), rated output P (k+1), itself and the power before not applying disturbance quantity is allowed to compare P (k+1)-P (k), the direction that result reflection power after comparing changes, if result is power increase direction, then increase the amount dU+T of disturbance when disturbance next time applies again.This step of carrying out so repeatedly, until occur that disturbance applies front and back power and compares result emergent power reduction direction.

Step 3 is when emergent power reduces direction result, and gathering the real-time port voltage of photovoltaic battery panel is U (y), then start to apply reverse disturbance U (y)-dU, reduces the amount dU-T of disturbance when meanwhile disturbance next time applies.When emergent power comparative result is the direction of reflection power change, then enter step 2.

Magnitude of voltage U (z) corresponding when step 4 finds out cell panel Maximum Power Output, MPPT controls to terminate.

First the present invention arranges an initial disturbance amount dU, after entering steady state (SS) after once completing to port voltage disturbance, sampling current voltage U (k+1), I (k+1) calculate power P (k+1), differ with the power P (k-1) before dropping into disturbance again.

As P (k+1)-P (k) >0, illustrate that power just changes towards augment direction, then increase a T=50%*dU at upper once disturbance quantity dU, thus the method comparing fixing disturbance step-length searches out maximum power point more fast.

When P (k+1)-P (k) <0 appears in first time, illustrate and searched out maximum power point, then reduce a T=50%*dU at upper once disturbance quantity dU, thus reduce the concussion loss at maximum power point place.

Beneficial effect: the variable and change direction of a kind of step-length that the present invention proposes has the MPPT control method of self-adaptation row, compare traditional disturbance observation, the search peak power spot speed caused because disturbance step-length is fixed is comparatively slow and occur the deficiency of larger oscillation at maximum power point, and the MPPT algorithm proposing a kind of disturbance adaptive step reaches good steady-state behaviour and dynamic property.The technical scheme conceived of the present invention is compared with existing technical scheme in general, effectively improves the precision of speed and the steady timing tracking maximum power point searching maximum power point.

Accompanying drawing explanation

Fig. 1 is I-U and the P-U family curve of photovoltaic cell;

Fig. 2 is the process flow diagram that the present invention is based on the adaptive MPPT control method of disturbance.

Embodiment

The one that the present invention proposes based on the adaptive MPPT control method of disturbance be one from searching process, namely by control end voltage, make photovoltaic cell can under various different sunshine and temperature environment intelligently Maximum Power Output.Can be realized by the adaptive change of disturbance step-length, hunt out maximum power point fast, improve its precision simultaneously.

Fig. 1 and embodiment by reference to the accompanying drawings, the present invention is described in detail.

Execution said process like this can find out maximum power point fast and accurately, and efficiently reduces the oscillation when following the tracks of maximum power point simultaneously.

The above is only embodiments of the invention, not any pro forma restriction is done to the present invention, every any simple modification, equivalent variations and decoration done above embodiment according to technical spirit of the present invention, all should be included in right of the present invention.

Claims

1. based on the adaptive MPPT control method of disturbance, it is characterized in that, concrete steps are:

Step one, when photovoltaic battery panel is started working, port voltage U (k) and electric current I (k) are gathered, calculating realtime power P (k), when the theoretical peak power of itself and cell panel compares when there is difference, then starting maximum power control;

Step 2, apply an initial disturbance amount dU to port voltage U (k), gather photovoltaic battery panel stablize after real-time port voltage data U (k+1)=U (k)+dU and current data I (k+1), rated output P (k+1), itself and the power before not applying disturbance quantity is allowed to compare P (k+1)-P (k), the direction that result reflection power after comparing changes, if result is power increase direction, when then disturbance next time applies again, increment is T, the disturbance quantity dU+T after increase; This step of carrying out so repeatedly, until occur that disturbance applies front and back power and compares result emergent power reduction direction;

Step 3, when emergent power reduce direction result time, gathering the real-time port voltage of photovoltaic battery panel is U (y), then start to apply reverse disturbance U (y)-dU, when meanwhile disturbance next time applies, decrement is T, the disturbance quantity dU-T after minimizing; When emergent power comparative result is the direction of reflection power change, then enter step 2;

Step 4, magnitude of voltage U (z) corresponding when finding out cell panel Maximum Power Output, MPPT controls to terminate.

2. MPPT control method according to claim 1, it is characterized in that: as P (k+1)-P (k) >0, illustrate that power just changes towards augment direction, then increase a T=50%*dU at upper once disturbance quantity dU, thus the method comparing fixing disturbance step-length searches out maximum power point more fast;