太陽能作為新能源能為人們的日常生活提供清潔無污染的能源。由于光伏發電系統產生的電流為直流電，但民用電力以交流供電為主，且太陽能發電最終將走向并網運行，這就意味著太陽能發電必須通過逆變器將直流電轉換為交流電來驅動家用電器等負載。因此，逆變器在太陽能發電系統中具有舉足輕重的作用。那么，鋁電解電容在新能源領域光伏逆變器產品上有哪些具體的應用呢？
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.太陽能發電對光伏逆變器的要求
Requirements for photovoltaic inverters for solar power generation
現有光伏系統逆變器的使用情況來看，它們一般只能使用5到10年，而光伏電池板的使用壽命長達25年，逆變器成為光伏系統中可靠性最低的組件。太陽能逆變技術業界對于產品壽命有很高的期望，一般都能保證20至25年的使用期，因此特別著重每種元件的可靠性。
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.提高光伏逆變器壽命的關鍵
Key to improving the life of photovoltaic inverters
決定光伏逆變器的壽命為其各元件的可靠性，盡管半導體元件通常都達到這種可靠性水平，但對于無源元件來說卻有可能是一個挑戰，特別是電解電容器。電解電容器的可靠性提高成為了提高光伏逆變器可靠性的關鍵之一。
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.電解電容器在光伏逆變器中的作用
The role of electrolytic capacitors in photovoltaic inverters
光伏逆變器可看成是用直流電源供電的特殊用途的變頻器，輸出頻率為50Hz或與電網同步的50Hz，其作用為吸收由逆變器產生的開關頻率極高次諧波電流和輸出頻率的三倍頻電流和高次諧波電流。
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.光伏逆變器對電解電容器的要求
Requirements of photovoltaic inverters for electrolytic capacitors
一般大功率的光伏逆變器，將轉化后的交流電直接并入高壓電網中，但從安規角度考慮，光伏電池組的輸出電壓一般不高于900V，可以選擇兩只450V電解電容器串聯，但為了提高安全性，可以選擇2只500V電解電容器串聯。所以需要高電壓等級的電容器來減少電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.
一般光伏逆變器流過電容器的電流為逆變器輸出電流有效值的0.44倍。如果一只電解電容器的額定電流不能滿足要求，要選擇多只電解電容器并聯方式獲得所需要的電流值。所以要求單只高耐紋波能力的電解電容器來減少電解電容器的并聯數量，提高整體可靠性。
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.
在太陽能發電系統中光伏電池板的使用壽命長達25年，而逆變器成為光伏系統一般只能使用5到10年，所以太陽能發電系統對光伏逆變系統的壽命要求為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.
對于無源元件鋁電解電容器，它的負極為電解液，會隨著使用時間的增長慢慢干涸而失效。這勢必需要電解電容器行業制造出更長壽命的電解電容器來符合光伏逆變器的要求。
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.
電解電容器的內部有儲存電荷的電解質材料，分正、負極性，類似于電池，不可接反。正極為粘有氧化膜的金屬基板，負極通過金屬極板與電解質（固體和非固體）相連接。電解電容器紙，又稱電容器隔膜紙，它在電解電容器的陽極和陰極鋁箔之間起隔離、絕緣作用。電解電容器紙的質量越好，越能滿足電容器耐壓、低阻抗、損耗小的要求。
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.
（雙極性）電解電容器采用雙氧化膜結構，類似于兩只有極性電解電容器將兩個負極相連接后構成，其兩個電極分別為兩個金屬極板（均粘有氧化膜）相連，兩組氧化膜中間為電解質。有極性電解電容器通常在電源電路或中頻、低頻電路中起電源濾波，退耦、信號耦合及時間常數設定、隔直流燈作用。無極性電解電容器通常用于音響分頻器電路、電視機S校正電路及單相發動機的起動電路。
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.
