EI-type transformers have gaps and large magnetic leakage, while toroidal transformers have closed magnetic circuits and small magnetic leakage. For the production of low-power inverter transformers, the cost of EI-type transformers is lower than that of toroidal transformers. However, when manufacturing high-power transformers, the cost of EI-type transformers is higher than that of toroidal transformers. At the same time, the heat output is high and the working efficiency is 10% lower. The toroidal transformer has low loss and long life.
The switching power supply is widely used in inverter because of its light weight, small size, and low inrush current. However, the switching power supply has low efficiency, high noise, and low reliability. If you want to output a sine wave, the cost is high, and Its design flexibility is low.