As the core component of a power generation system, the lifespan of an inverter directly affects the normal operation of the entire power station, and the lifespan of the inverter has become a concern for many people. What are the factors that directly affect the lifespan of the inverter? In the following article, we will analyze the key factors that affect the lifespan of the smart hybrid inverter from the aspects of component lifespan, design, and installation.
In theory, inverters belong to switching power supplies, so their constituent components can generally be divided into resistors, capacitors, diodes, power devices (IGBT or MOS tube), inductors, transformers, current sensors, ICs, optocouplers, and relays.
Resistors, surface-mounted capacitors, and ceramic capacitors typically have a lifespan of20 years or more. Inductors and transformers are theoretically effective as long as they do not exceed their raw material temperature. Small power diodes and transistors can operate for100,000 hours or more. The mechanical lifespan of relays is usually more than1 million times, and the electrical lifespan exceeds10,000 times. Power devices such as IGBT or MOS tube are usually not considered from the perspective of lifespan if they meet the design specifications. Fans and fuses are consumables that do not significantly affect the lifespan of inverters and can be replaced on schedule. The lifespan of film capacitors is typically more than100,000 hours, and the lifespan of electrolytic capacitors is typically between2,000-3,000 hours under105℃, and the longer lifespan is only5,000-6,000 hours. However, as the temperature decreases by10℃, the lifespan doubles. Therefore, the shortcoming of components in the inverter lies mainly in the lifespan of electrolytic capacitors.
The lifespan of components is the fundamental element that ensures the lifespan of an inverter, while high-quality design is the core element that ensures the lifespan of a hybrid inverter. What design elements can severely impact the lifespan of an inverter but are difficult to detect in the short term?
Temperature is a major factor that directly affects the lifespan of an inverter, especially for components such as electrolytic capacitors and optocouplers. For every 10℃ increase in temperature, the lifespan of electrolytic capacitors is reduced by half, and excessive temperature can also accelerate optocoupler light degradation. However, optocouplers are usually used for driving IGBTs, and their failure can damage the IGBTs.
Relays have a lifespan of up to one million times when switching at zero current, but their lifespan almost follows a coefficient loss pattern with an increase in switching current. Accurate software control is the main factor that ensures the lifespan of a relay when switching at zero current.
Inverter environments are usually harsh, with many factors affecting them, such as poor grid quality and high inductive loads. If the inverter protection function and EMC design are not good enough, it is susceptible to external influences. Once the IGBT driver is affected, it can easily cause misdirection and lead to a catastrophic failure.
Although string inverters have an IP65 protection level and can be installed indoors and outdoors, the installation environment can still have a significant impact on their lifespan. Installing an inverter in an environment with high sunlight exposure, humidity, and acidity/alkalinity can reduce its lifespan. Exposure to direct sunlight can also lead to overheating and power reduction, thus affecting power generation. Selecting a suitable installation environment is crucial for ensuring the lifespan of a hybrid inverter.
Although there are many factors that directly affect the lifespan of a pure sine wave inverter, if the components are selected properly and the design is of high quality, the inverter can run stably for at least 10 years. Therefore, we recommend using an inverter to provide security for your power station.