Inverter verification is the key to the success of solar photovoltaic systems

As the price of solar photovoltaic modules falls into the curse of Moore's Law, it also accelerates the advent of the era of solar energy popularization. As the global production of solar photovoltaic modules continues to rise, prices continue to bottom out, and quality continues to rise, it predicts that solar renewable energy will become an important decentralized independent power source and will also promote the development of future smart grids. Among them, the inverter plays the role of an independent power supply and is also the gatekeeper of the interface between the future power grid and solar photovoltaics. It has also become the key to the success of solar photovoltaics and grid-connected development.

UL Asia Consulting Business Development Manager Chen Limin believes that among the many testing and certification requirements, the most easily overlooked is the reliability verification of the inverter, or the so-called service life verification.

Figure: UL Asia Consulting Business Development Manager Chen Limin believes that among the many testing and certification requirements, the most easily overlooked is the reliability verification of the inverter, or the so-called service life verification.

UL Asia Consulting Business Development Manager Chen Limin pointed out that since the output of solar cells is direct current, and the current commonly used electrical system in the world is alternating current, the current output by solar cells must be converted to alternating current and transformed before it can be used by electrical products. The device that performs the functions of alternating current and transformation is called an inverter, commonly known as an inverter or frequency converter. Unlike the variable operating frequency of the so-called variable frequency air conditioner, the inverter of solar photovoltaics must output the same and stable output frequency as the power grid in order to enable the electrical equipment to operate stably and continuously.

Chen Limin said that as a power supply device, the verifications that an inverter generally needs to obtain include conversion efficiency, functional characteristics, and electrical safety. Among them, electrical safety is the most important; conversion efficiency is closely related to investment returns and government subsidies; among functional characteristics, voltage and frequency stability is related to load stability, which are also two important characteristics that are generally valued by the industry.

Chen Limin believes that among the many testing and certification requirements, the most easily overlooked is the reliability verification of the inverter or the so-called service life verification. Due to the simple electromechanical structure of solar modules, a service life of 20 to 30 years is not a problem. However, due to the use of a large number of electronic control components and frequent operation frequency, the inverter currently has a service life of only about five years, which is often overlooked as a key cost of solar photovoltaic systems.