Aluminum electrolytic capacitors are most widely used in photovoltaic inverters. The current generated by photovoltaic power generation system is DC, but civil power is mainly AC power supply, and solar power generation will eventually move to grid connected operation, which means that solar power generation must convert DC into AC through inverter to drive loads such as household appliances. Therefore, inverter plays an important role in solar power generation system.
The requirements of photovoltaic inverter for aluminum electrolytic capacitor are mainly reflected in high voltage, high ripple resistance and long life.
Generally, high-power photovoltaic inverter directly integrates the converted AC into the high-voltage power grid. However, from the perspective of safety regulations, the output voltage of photovoltaic battery pack is generally not higher than 900v. Two 450V electrolytic capacitors can be selected in series. However, in order to improve safety, two 500V electrolytic capacitors can be selected in series. Therefore, high voltage capacitors are needed to reduce the series connection of capacitors and improve reliability.
High ripple resistance
In general, the current flowing through the capacitor of photovoltaic inverter is 0.44 times of the effective value of inverter output current. If the output voltage of the photovoltaic inverter is 250V, the output current corresponding to 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 100kW photovoltaic inverter needs to flow 112a RMS current, and the rated current of the selected capacitor shall not be lower than this value. If the rated current of one electrolytic capacitor cannot meet the requirements, 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 the overall reliability.
In the solar power generation system, the service life of photovoltaic panels is up to 25 years, while the inverter can only be used for 5 to 10 years. Therefore, the service life of photovoltaic inverter system in solar power generation system is required to be 25 years. For passive component electrolytic capacitor, its negative electrode is electrolyte, which will slowly dry up and fail with the increase of service time. This is bound to require the electrolytic capacitor industry to manufacture electrolytic capacitors with longer life to meet the requirements of photovoltaic inverter.
Sanhe bolted aluminum electrolytic capacitor is the most widely used in the photovoltaic inverter industry. After reliability test, it fully meets the requirements of long life, high ripple and high voltage in the field of new energy. If you just need to purchase the capacitor of photovoltaic inverter, please contact us, and we will provide you with spot and technical support at the first time.