(1) square wave inverter
The AC voltage output of the square wave inverter is square wave. The inverters used in such inverters are not exactly the same, but the common feature is that the lines are relatively simple and the number of power switches used is very small. The design power is usually between 100 watts and kilowatts. The advantages of square wave inverter are simple line, cheap price and convenient maintenance. The disadvantage is that the square wave voltage contains a large number of high-order harmonics, which will cause additional losses in load electrical appliances with core inductors or transformers, and interfere with radio and some communication devices. In addition, this kind of inverter is not wide, the protection function is not perfect, the noise is big and so on.
Scope of use: places for emergency use of electricity, car, shopping malls and field.
The performance characteristics are:
1) the power frequency transformer is large in volume and weight, and the utilization rate of the push-pull original side winding is low, and the utilization ratio of the bridge type winding is high.
2) the volume and weight of the output four order AC filters are large, and the Lf1 and Cf1 in the power channel have greater loss.
3) for the fluctuation of the voltage and load of the power grid, the dynamic response characteristic of the system is poor.
4) the audio noise produced by the transformer and the output filter inductor is large.
5) the push-pull circuit has a simple topology and high power switch voltage stress (2Ui), which is suitable for low input voltage inverters. The bridge type circuit has many power switches and low switching voltage stress (Ui), which is suitable for high input voltage inverters.