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PERTURBATION OBSERVATION BASED ON POWER PREDICTION

Author: Source: Datetime: 2016-10-05 01:19:26
The above-mentioned perturbation method of variable step can effectively solve the contradiction between tracking speed and accuracy, but still can not overcome the problem of misjudgment of disturbance observer. From the analysis of the miscarriage of justice problem, we can see that the working point sequence does not fall on a single characteristic curve, but is composed of the operating points on different characteristic curves in the case of rapid change of irradiance. Therefore, If a search based on a single characteristic curve to determine solar power batteries, there may be miscarriage of justice. In fact, for the miscarriage of justice problem shown in Figure 6-10, the situation of multiple characteristic curves can be pre-estimated to overcome the misjudgment of the perturbation observation method, which is based on the power of the perturbation observation method, the basic principles of discussion as follows:

The perturbation method of the fixed step is based on static, "characteristic curve search, and in fact, the irradiance is time-varying, that is, wide" characteristic curve has been in a dynamic process of change. If at the same time can be measured under the same irradiance BU. Characteristic curve of the voltage perturbation, after the corresponding two operating point power, and the perturbation observation method to determine, then there will not be miscarriage of justice, it is clear that this is impossible to achieve. When the power in the hysteresis loop shown in Figure 6-13 hysteresis technology diagram dynamic, the solar power batteries operating point voltage remains unchanged, only when the power fluctuations in excess of the set hysteresis, only in accordance with certain laws Change the operating point voltage. It can be seen that the introduction of the hysteresis loop can effectively suppress the oscillation phenomenon of the disturbance observer. In fact, the misjudgment can be seen as a dynamic oscillation process when the external environment changes, so the method can also overcome the miscarriage of justice phenomenon.
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The perturbation method of the fixed step is to decide whether to increase or decrease the voltage of the working point by comparing the power difference between the two points before and after the disturbance. Although the cause of the oscillation or misjudgment is different in the course of use, Based on the unidirectional disturbances of the instantaneous measured values, it is possible to overcome the oscillation or misjudgment problem of the perturbation method if the additional measurement information is added and bidirectional disturbances with hysteresis characteristics are added. It is easy to see that the hysteresis comparison method is to ensure the reliability of the perturbation observation method to avoid the occurrence of miscarriage of justice, and also to effectively suppress the oscillation near the maximum power point. The following is a detailed analysis of hysteresis comparison method to suppress oscillation and misjudgment of the principle of the process.

Although the hysteresis comparison method can largely avoid the phenomenon of oscillation and miscarriage of justice, but if the step is too large, the operating point may stay away from the maximum power point in the region, if the step is too small, in the new round of search Initially, the operating point will be in the area away from the maximum power point search for a long time, so the speed and accuracy of the contradictions still exist. To solve this problem, we can use variable step-size hysteresis comparison method to solve this contradiction, the specific variable step method can refer to the previous relevant content.

Compared with the fixed-step perturbation method, the variable step-size hysteresis comparison method can effectively overcome the oscillation and miscarriage of justice phenomenon, taking into account the requirements of speed and accuracy, to more accurately track the maximum power point of solar power batteries, thereby enhancing The efficiency of solar power generator system. The main advantage of the conductance increment method is that the control stability is high. When the external environmental parameters change, the system can track the change smoothly, and has nothing to do with the characteristics and parameters of the solar power batteriesl. In addition, the voltage initialization parameters have a great influence on the tracking performance of the system along the moving process, if not properly set may have a greater power loss. TAG: Engie Amazon Bank World Battery-Storage Changsha Jolywood Nuon German Category Separate Telangana MW 10 Used