Photovoltaic power gener

Abstract: under the trend of global environmental protection, the new energy field will usher in a rapid development. Government input and input from enterprises will accelerate the development of new energy fields. This paper describes the principle of photovoltaic inverter and its requirements for components in the field of photovoltaic power generation in the new energy field.
Key words: new energy, photovoltaic solar power, photovoltaic inverter, aluminum electrolytic capacitor

Solar energy, as a new energy source, can provide clean and pollution-free energy for our life. As the current generated by the photovoltaic power system is DC, the civil electricity is mainly AC power supply, and the solar power will eventually move to the grid, which means that the solar power must be converted into alternating current to drive the household appliances through the inverter. Therefore, inverter plays an important role in the solar power system.
The main function of the inverter is to convert the variable DC voltage input into the non interfering AC sinusoidal output, which can be used both for the use of the equipment and to the power grid.
1. Requirements of solar power generation for photovoltaic Inverters
For engineers familiar with power management, what are the main points of designing inverter for solar power system? First, as far as the current photovoltaic inverter is used, they can only use only 5 to 10 years, while the life span of photovoltaic panels is 25 years, and the inverter has become the lowest reliability component in the photovoltaic system. AlbertoGuerra of IR suggests that designers must consider the service life of PV system inverters. The solar inverter technology industry has a high expectation of product life, and generally can guarantee the use period of 20 to 25 years, so the reliability of each component is particularly emphasized.
Two, the key to improve the life of photovoltaic inverter
It is determined that the life of the photovoltaic inverter is the reliability of all the components, although the semiconductor components usually reach this level of reliability, but it is possible for the passive components to be a challenge, especially the electrolytic capacitor. The reliability improvement of electrolytic capacitors has become one of the keys to improve the reliability of PV inverters.
Three. The role of electrolytic capacitors in photovoltaic inverters.
PV inverter can be regarded as a special purpose frequency converter powered by DC power supply, and the output frequency is 50Hz or 50Hz synchronized with power grid. There is no current pulse in the rectifier generated by the rectifier, so that the capacitor on the DC bus is a DC bus capacitor or a "DC-Link" capacitor, which is used to absorb the three frequency doubling current and the high harmonic current of the high harmonic current of the switching frequency and the output frequency produced by the inverter.
Four, photovoltaic inverter requirements for electrolytic capacitors 1. high voltage
Generally, the high-power PV inverter takes the converted AC directly into the high voltage power grid, but from the angle of safety regulation, the output voltage of the photovoltaic cell group is generally not higher than 900V, and two 450V electrolytic capacitors can be selected in series. In order to improve the safety, 2 500V electrolytic capacitors can be selected in series. Therefore, capacitors with high voltage level are needed to reduce capacitor series connection and improve reliability.
2. high resistance to ripple
The current of the general photovoltaic inverter flowing through the capacitor is 0.44 times the effective value of the output current of the inverter. If the output voltage of the PV inverter is 250V, the output current of each output 1kW power is about 2.54A, and the current flowing through the DC bus capacitor is 1.12A. The DC bus capacitor of the 100kW PV inverter needs to flow through the 112A RMS current. The rated current of the selected capacitor should not be lower than this value. If the rated current of an electrolytic capacitor can not meet the requirements, it is necessary to select more electrolytic capacitors in parallel to obtain the required current value. Therefore, only one electrolytic capacitor with high ripple resistance is required to reduce the number of parallel capacitors and improve the overall reliability.
3. long life
In solar power systems, photovoltaic panels are used for up to 25 years, while inverters can only be used for 5 to 10 years as photovoltaic systems, so the solar power system requires a life of 25 years for the photovoltaic inverter system. For passive component electrolytic capacitors, its negative electrode is electrolyte, which will dry up and fail with the increase of service time. This will inevitably require the electrolytic capacitor industry to produce longer life electrolytic capacitors to meet the requirements of photovoltaic inverters.
Five, BIT electrolytic capacitor
Shanghai one point Electronic Technology Co., Ltd. is a company specializing in the manufacture of bolted aluminum electrolytic capacitors for more than 10 years. After more than 3 years of research and development, the formula of electrolyte was improved. The important chemicals in the electrolyte were imported from Japan, and the high performance electrolyte was developed successfully. The reliability test fully meets the requirements of the new energy field for long life, high ripple and high voltage. Finally, in early 2011, special ES6 and EL20 were introduced in the new energy field.
At present, the long life aluminum electrolytic capacitor in the market is 85 and 5000 hours, and the ES6 series of BIT can guarantee the life of 85 and 6000 hours under the same condition, and the resistance to ripple is 1.7 times that of the ordinary long life type. It improves the life and ripple resistance of the electrolytic capacitor, and is in line with the ordinary photovoltaic inverter to the capacitor. Requirement。 The EL20 ultra long life type electrolytic capacitor of BIT has reached 85, 20000 hour life, and the resistance to ripple is 1.9 times that of the ordinary long life type. It can fully meet the needs of the long life of the photovoltaic inverter, and can greatly improve the reliability level of the photovoltaic inverter, which meets the requirements of the solar energy generation system. With the continuous progress of the new energy field and the related industries, it is believed that the solar power generation technology will develop rapidly, and the reliability of the solar power generation system will be continuously improved. Our BIT people are willing to work together with you to provide more advanced electrolytic capacitors for the development of new energy, and contribute to the construction of green earth.
Six. Conclusion
The progress of aluminum electrolytic capacitors and other life components makes the long life of PV inverter possible. With the continuous development of reliability of life components, the life of PV inverter will meet the requirements of solar power generation system. The future solar power system will become a highly reliable, maintenance free power generation system; solar energy will also become clean and pollution-free and cheap energy into thousands of households.