博文

目前显示的是 四月, 2018的博文

Attention to the use of switching power supply

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1.Before using the power supply, make sure whether the input and output voltage specifications are consistent with the nominal values of the power supply. 2.Before electrifying, check if the input and output leads are connected correctly, so as not to damage user equipment. 3.Check whether the installation is solid, whether there is contact between the installation screws and the power supply devices, and measure the insulation resistance of the housing and input and output, so as to avoid electric shock. 4.In order to ensure safety and reduce interference, ensure that the grounding terminal is reliably grounded. 5.The output power is usually divided into main and auxiliary output, and the main output characteristic is superior to the auxiliary output. In general, the output current is large and the output is mainly. In order to guarantee the output load adjustment rate and output dynamic performance, it is generally required to carry at least 10% load per route. If the auxiliary road

Heat dissipation design of solar inverters

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The main task of the  solar inverter  heat radiation system is to select a reasonable heat dissipation and cooling method, to control the temperature of the electronic components under the specified value, to provide a low heat resistance channel between the heat source and the external environment, so as to ensure that the heat can be sent out smoothly. (1)Loss calculation To design the heat dissipation system, the heat of the inverter must first be calculated. The main heat generating devices of the inverter are the power switch tube and the filter inductor, and the transformer. The efficiency of transformers and inductors can be customized by consultation with manufacturers. The loss of the power switch tube can be calculated by software simulation. The loss is related to the output current, the DC voltage, the power factor, the overload coefficient, the modulation coefficient and the output frequency. (2)Selection of heat dissipation method The thermal design of electr

Why does a solar power system produce leakage current

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The leakage current of the  solar power system , also known as the square array residual current, is essentially common mode current, which is caused by the existence of parasitic capacitance between the solar power system and the earth. When the parasitic capacitance, and solar power system and the power grid forms a loop, the common mode voltage will produce common mode current on the parasitic capacitance. When the low frequency transformer is installed in the solar power system, the parasitic capacitance impedance of the transformer windings in the loop is relatively large, so the common mode current produced by the loop voltage of the CCP can be restrained. However, in a solar power system without transformer, the circuit impedance is relatively small, and the common mode voltage will form a larger common mode current on the parasitic capacitance between the solar power system and the earth, that is, leakage current. The leakage current in the solar power system includes the DC

How to choose the inverter for cold weather to ensure normal operation of PV power station

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Low temperature will bring changes in physical properties of electronic components, and this change tends to be in an unfavorable direction. Blizzard has a great impact on photovoltaic power stations. Too thick snow will lead to over icing of components, affecting the power generation and life of the system, resulting in a decline in power generation and even stop work. For  solar inverter , it is a severe test. Cold climate conditions may make the inverter can not work steadily, such as can not start, frequent alarm, power generation reduction and other problems. How to choose inverter to deal with the erosion of extreme weather? 1.Select components of wide range of working temperature to fully meet the low temperature service conditions. 2.Takes full account of the demand for low temperature work in the design of the product, leaving enough margin (including capacity margin and time margin). 3.The product should be tested for a long time at low temperature to ensure the valida

Why the terminal needs to select large capacity modularized UPS

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The power supply system belongs to the airport public equipment, and the public equipment space of the airport terminal is limited. For the airport construction department, centralized power supply system needs to minimize the occupancy space under the premise of ensuring reliability. The traditional large capacity tower type UPS occupies a large space, and occupies more than twice the space occupied by  modular UPS . If the 2N system is adopted, the space will be larger, and the space of the battery should be added, which is not suitable for the airport. Therefore, considering the comprehensive consideration of airport construction department, modular UPS should be selected. The same capacity occupies almost half of the traditional tower UPS. At the same time, the active devices such as modular UPS power module, bypass module, control module and other active devices are all designed by hot plug. The system can meet the requirements of the airport to the reliability of the UPS by us

Why does photovoltaic system generate leakage current and what is its harm

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The leakage current of the  solar power system  is essentially common mode current, which is caused by the existence of parasitic capacitance between the photovoltaic system and the earth. When the parasitic capacitance – photovoltaic system – power grid three forms a loop, the common mode voltage will produce common mode current on the parasitic capacitance. When the power frequency transformer is installed in the photovoltaic system, the parasitic capacitance impedance of the transformer windings in the loop is relatively large, so the common mode current produced by the loop voltage of the CCP can be restrained. However, in a photovoltaic system without transformer, the circuit impedance is relatively small, and the common mode voltage will form a larger common mode current on the parasitic capacitance between the photovoltaic system and the earth, that is, leakage current. The leakage current in the photovoltaic system includes the DC and AC parts. If the grid is connected to th

The main classification of switching power supply

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In the  switching power supply  technology, people the develop the electronic devices, while the development of switching frequency conversion technology to promote the switch power supply with growth rate of over two figures to become light, digital, small, thin, low noise, high reliability and anti interference. Switching power supply can be divided into two major categories: AC/DC and DC/DC. Miniature low power switching power supply Switching power supply is becoming more and more popular and miniaturized. Switching power supply will gradually replace all applications of transformers in life. The application of low power micro switching power supply should be firstly reflected in digital display meter, smart meter, mobile phone charger, etc.. At this stage, the state is promoting the construction of smart grid, the demand for power meter greatly improved, switching power supply will gradually replace the transformer in the energy meter above the application. Reverse type

Composition and working principle of wind solar hybrid power supply system

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Wind  solar hybrid power supply system  is mainly composed of wind turbine, photovoltaic array,  solar charging controller , battery pack and inverter. The wind turbine generates alternating current with the voltage of the system, and converts the solar charge controller into the DC power adapted to the system voltage, which is connected to the battery group and the  solar inverter . PV array generates DC power that is compatible with system voltage, and is connected to battery pack and inverter by charging controller. The solar inverter converts the direct current input from the wind turbine and the PV array to 220V and 50Hz alternating current to provide AC load. The battery pack stores spare power which is not consumed by the load. When the wind turbine and PV array power generation is insufficient, the power consumption of the load is supplemented by the battery pack. When the wind turbine and the photovoltaic array do not generate electricity, the DC power stored in the battery