The distributed solution schemes the mppt function from the inverter to the combiner box without changing the stable topological structure of the traditional centralized energy collection and centralized grid connection, so that each “distributed combiner box†(distributed scheme to DC) The professional name of the confluence equipment is to add “distribution type†in front of the “comport box†to distinguish it. It can match up to 1 channel MPP tracking every 2 channels, so a 16-way incoming line distribution box has 8-channel mppt tracking. If a 1 MW square array needs to be equipped with 12 16-channel incoming collectors, then the 1 MW square has almost 100 MPP tracking. Compared to the centralized 1 MW, there are only 8 MPP tracking. The distributed type has greatly increased the number of mppts, thus greatly reducing the impact of parallel mismatched photovoltaic power generation. Mppt Mppt (Maximum Power Point Tracing), which is the maximum power point tracking. Because the utilization rate of photovoltaic cells is not only related to its internal characteristics, but also affected by factors such as sunshine and temperature, its output characteristics are strongly correlated with panel temperature, illumination and intensity, and have nonlinear characteristics. According to the parameters of photovoltaic cells, the typical IV and PV characteristics of photovoltaic cells are shown in Figure 1 under the same temperature and different illumination conditions. Figure 1 IV and PV characteristics of photovoltaic cells at the same temperature and different light conditions According to the parameters of photovoltaic cells, the typical IV and PV characteristics of photovoltaic cells are shown in Figure 2 under the same light intensity and temperature: Figure 2 Typical IV characteristics and PV characteristics at the same light intensity and temperature When the temperature is the same, the open circuit voltage of the photovoltaic cell is almost unchanged with the increase of the irradiance; when the irradiance is the same, the short-circuit current of the photovoltaic cell is almost unchanged with the increase of the temperature. It can be seen that the temperature change mainly affects the output voltage of the photovoltaic cell, and the irradiance changes mainly affect the output current of the photovoltaic cell. Photovoltaic cells are approximated as a DC source with little change in illumination and temperature. As can be seen from the PV characteristics of the above typical photovoltaic cells, for maximum utilization, the photovoltaic cells need to operate at different and unique maximum power points (MPP - Maximum Power Point). Therefore, for all photovoltaic power generation systems, the optimal working state of the photovoltaic cell array should be sought to maximize the conversion of light energy into electrical energy. The maximum power point will correspond to a working voltage. This is the maximum power point voltage because of photovoltaics. The maximum power point operating voltage of the battery array will be changed by factors such as sunshine intensity, device junction temperature, and external load. Therefore, the mppt function is to track the maximum power point voltage in real time, so that the photovoltaic cell module always works at the maximum power point voltage, so that the maximum Limit the use of photovoltaic panels to generate electricity. Multi-channel mppt boosts power generation Because the photovoltaic cell array is composed of a unit photovoltaic cell string, each string has its own working voltage, and the voltage is very inconsistent. If the traditional centralized scheme is used, the string will be paralleled when the combiner energy is collected. A parallel mismatch occurs, and a parallel mismatch occurs when the combiner box and the inverter energy are connected in parallel, which seriously affects the power generation efficiency of the photovoltaic cell module. As shown in Figure 3 below, in the case of single mppt, the photovoltaic module is affected by various factors, which will lead to the occurrence of two or more peaks, and tracking any peak will cause loss of power generation. In the case of multi-channel mppt, the characteristics of each string can be accurately tracked to form a plurality of mppt curves, so that the maximum performance of each string of photovoltaic cells can play a role. Figure 3 Single mppt curve comparison There are many factors that cause the PV series and parallel mismatch, such as shadow obscuration, inconsistency and attenuation inconsistency of components shipped from the factory, inconsistent tilt angles of photovoltaic modules due to terrain limitations, and inconsistent temperature and illumination in large areas of photovoltaic power plants. and many more. If only one mppt tracking is used with a MW square matrix, the parallel mismatch effect will be very large. If shadow occlusion, temperature/light inconsistency, and inconsistent component performance are probabilistic factors, the parallel loss caused by the inconsistent tilt angle of photovoltaic panel installation is basically a decisive factor in complex terrain such as mountains. The distributed multi-channel mppt technology design is fine to 1 mppt tracking for every 2 PV strings, and the regulated output is boosted after the booster combiner box, which solves the problem of parallel mismatch. As shown in Figure 4 below, multi-channel mppt can form multiple mppt curve traces, and each two strings form an mppt curve. This refinement makes the maximum efficiency of every two strings play a role to solve the parallel mismatch problem of photovoltaic power plants. , greatly improve the power generation of photovoltaic power stations, thereby greatly increasing the revenue of the power station. Figure 4 multi-channel mppt curve Some research institutes have used software to measure the effect of multi-channel mppt, and selected a PV power plant site in Inner Mongolia. The test concluded that multi-channel mppt can indeed increase a lot of power generation. Figure 5 multi-channel mppt software test renderings Figure 5 above is a screenshot of the monitoring software. It can be seen from the figure that the output power of power unit 2 and power unit 3 are the same, while the input voltages of power unit 2 and power unit 3 are very different (unit 2 input voltage 621V, unit 3 The input voltage of 586V) fully proves that even with the configuration of the same battery string, the maximum power point voltage may be inconsistent due to the complex environment of the power station site. summary With the rapid development of photovoltaic grid-connected power generation technology, from the original traditional centralized 1MW square array, the maximum development of only 8 mppt to the distributed 1MW square array has 200 mppt, which is a true portrayal of human pursuit of excellence and excellence. The distributed solution improves the number of mppts in order of magnitude, and the ultimate fine-grained maximum power point tracking greatly reduces the parallel mismatch problem of photovoltaic power plant battery components. From the data obtained by many institutional tests, at least 3 can be improved. % of electricity generated. If the mountain, front-runner base, roof color steel tile project, etc., the increased power generation will be higher, more suitable for the terrain complex, the photovoltaic panel tilt angle can not be installed consistent project site applications. Dajiangdong goes to Langtaosha, and believes that the distributed scheme will occupy a very important place in the photovoltaic grid-connected power station. Our Musical Mug is good in quality and competitive in price. We are manufacturer and supplier of Musical Mug following your specific requirement. We are looking forward to your
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Mppt is the maximum power point tracking. Because the utilization rate of photovoltaic cells is not only related to its internal characteristics, but also affected by factors such as sunshine and temperature, its output characteristics are strongly correlated with panel temperature, illumination and intensity, and have nonlinear characteristics.