As a new energy source, solar energy can provide clean and pollution-free energy for people's daily life. Due to the fact that the current generated by photovoltaic power generation systems is DC, but civil power is mainly AC powered, and solar power generation will eventually move towards grid connection, which means that solar power generation must convert DC power into AC power through inverters to drive loads such as household appliances. Therefore, inverters play an important role in solar power generation systems. So, what are the specific applications of aluminum electrolytic capacitors in photovoltaic inverter products in the new energy field?

　　1.太阳能发电对光伏逆变器的要求

　　Requirements for photovoltaic inverters for solar power generation

　　现有光伏系统逆变器的使用情况来看，它们一般只能使用5到10年，而光伏电池板的使用寿命长达25年，逆变器成为光伏系统中可靠性最低的组件。太阳能逆变技术业界对于产品寿命有很高的期望，一般都能保证20至25年的使用期，因此特别着重每种元件的可靠性。

　　According to the usage of inverters in existing photovoltaic systems, they can generally only be used for 5 to 10 years, while photovoltaic panels have a service life of up to 25 years, making inverters the most reliable components in photovoltaic systems. The solar inverter technology industry has high expectations for product life, generally guaranteeing a service life of 20 to 25 years, so special emphasis is placed on the reliability of each component.

　　2.提高光伏逆变器寿命的关键

　　Key to improving the life of photovoltaic inverters

　　决定光伏逆变器的寿命为其各元件的可靠性，尽管半导体元件通常都达到这种可靠性水平，但对于无源元件来说却有可能是一个挑战，特别是电解电容器。电解电容器的可靠性提高成为了提高光伏逆变器可靠性的关键之一。

　　The lifetime of photovoltaic inverters is determined by the reliability of their components. Although semiconductor components typically achieve this level of reliability, it can be a challenge for passive components, especially electrolytic capacitors. Improving the reliability of electrolytic capacitors has become one of the keys to improving the reliability of photovoltaic inverters.

　　3.电解电容器在光伏逆变器中的作用

　　The role of electrolytic capacitors in photovoltaic inverters

　　光伏逆变器可看成是用直流电源供电的特殊用途的变频器，输出频率为50Hz或与电网同步的50Hz，其作用为吸收由逆变器产生的开关频率极高次谐波电流和输出频率的三倍频电流和高次谐波电流。

　　Photovoltaic inverters can be seen as special purpose inverters powered by DC power, with an output frequency of 50Hz or 50Hz synchronized with the power grid. Their function is to absorb the switching frequency extremely high harmonic current generated by the inverter and the third harmonic current and high harmonic current of the output frequency.

　　4.光伏逆变器对电解电容器的要求

　　Requirements of photovoltaic inverters for electrolytic capacitors

　　一般大功率的光伏逆变器，将转化后的交流电直接并入高压电网中，但从安规角度考虑，光伏电池组的输出电压一般不高于900V，可以选择两只450V电解电容器串联，但为了提高安全性，可以选择2只500V电解电容器串联。所以需要高电压等级的电容器来减少电容器的串接而提高可靠性。

　　Generally, high-power photovoltaic inverters incorporate the converted AC power directly into the high-voltage power grid. However, from the perspective of safety regulations, the output voltage of photovoltaic battery packs is generally not higher than 900V, and two 450V electrolytic capacitors can be selected in series. However, to improve safety, two 500V electrolytic capacitors can be selected in series. Therefore, it is necessary to use high voltage level capacitors to reduce the series connection of capacitors and improve reliability.

　　一般光伏逆变器流过电容器的电流为逆变器输出电流有效值的0.44倍。如果一只电解电容器的额定电流不能满足要求，要选择多只电解电容器并联方式获得所需要的电流值。所以要求单只高耐纹波能力的电解电容器来减少电解电容器的并联数量，提高整体可靠性。

　　Generally, the current flowing through the capacitor of a photovoltaic inverter is 0.44 times the effective value of the inverter output current. If the rated current of one electrolytic capacitor cannot meet the requirements, it is necessary to select multiple electrolytic capacitors in parallel to obtain the required current value. Therefore, a single electrolytic capacitor with high ripple resistance is required to reduce the number of parallel electrolytic capacitors and improve overall reliability.

　　在太阳能发电系统中光伏电池板的使用寿命长达25年，而逆变器成为光伏系统一般只能使用5到10年，所以太阳能发电系统对光伏逆变系统的寿命要求为25年的水平。

　　In solar power generation systems, the service life of photovoltaic panels can be as long as 25 years, while inverters can only be used as photovoltaic systems for 5 to 10 years. Therefore, solar power generation systems require a service life of 25 years for photovoltaic inverter systems.

　　对于无源元件铝电解电容器，它的负极为电解液，会随着使用时间的增长慢慢干涸而失效。这势必需要电解电容器行业制造出更长寿命的电解电容器来符合光伏逆变器的要求。

　　For passive element aluminum electrolytic capacitors, their negative electrode is electrolyte, which will slowly dry up and become invalid as the service time increases. This is bound to require the electrolytic capacitor industry to manufacture electrolytic capacitors with longer life to meet the requirements of photovoltaic inverters.

　　电解电容器的内部有储存电荷的电解质材料，分正、负极性，类似于电池，不可接反。正极为粘有氧化膜的金属基板，负极通过金属极板与电解质（固体和非固体）相连接。电解电容器纸，又称电容器隔膜纸，它在电解电容器的阳极和阴极铝箔之间起隔离、绝缘作用。电解电容器纸的质量越好，越能满足电容器耐压、低阻抗、损耗小的要求。

　　The interior of an electrolytic capacitor has an electrolyte material that stores electric charges, with positive and negative polarity, similar to a battery, and cannot be connected in reverse. The positive electrode is a metal substrate adhered with an oxide film, and the negative electrode is connected to the electrolyte (solid and non solid) through a metal electrode plate. Electrolytic capacitor paper, also known as capacitor separator paper, serves as an isolation and insulation between the anode and cathode aluminum foil of an electrolytic capacitor. The better the quality of electrolytic capacitor paper, the better it can meet the requirements of capacitor voltage resistance, low impedance, and low loss.

　　（双极性）电解电容器采用双氧化膜结构，类似于两只有极性电解电容器将两个负极相连接后构成，其两个电极分别为两个金属极板（均粘有氧化膜）相连，两组氧化膜中间为电解质。有极性电解电容器通常在电源电路或中频、低频电路中起电源滤波，退耦、信号耦合及时间常数设定、隔直流灯作用。无极性电解电容器通常用于音响分频器电路、电视机S校正电路及单相发动机的起动电路。

　　The (bipolar) electrolytic capacitor adopts a double oxide film structure, similar to two polar electrolytic capacitors formed by connecting two negative electrodes. The two electrodes are connected by two metal electrode plates (both bonded with oxide films), and the middle of the two groups of oxide films is an electrolyte. Polarized electrolytic capacitors usually function as power filters, decoupling, signal coupling, time constant setting, and DC lamp isolation in power supply circuits or intermediate and low frequency circuits. Non polar electrolytic capacitors are commonly used in audio frequency divider circuits, television S correction circuits, and single-phase engine starting circuits.