Which type of inverter is described as lacking a transformer?

The type of inverter described as lacking a transformer is a non-isolated inverter. Non-isolated inverters convert the direct current (DC) produced by solar panels directly into alternating current (AC) without the use of a transformer to separate the input and output sides. This essentially means that the inverter uses power electronics to manage the voltage transformation, making it more lightweight and efficient when compared to isolated inverters that require transformers.

Non-isolated inverters typically exhibit higher efficiency due to fewer components and reduced energy losses. They are commonly used in applications where size and weight are crucial, and they are often seen in microinverters and power optimizers used in residential solar applications. Understanding this concept is important because it emphasizes the role of different inverter types in terms of efficiency, cost, and design in solar energy systems.