Switching device is used to control the circuit on and off components, it can control the circuit on and off. Common switching devices include diode, thyristor, mos tube, igbt and so on. igbt is a kind of switching device which inherits the advantages of mos tube and thyristor. It has the advantages of low on-voltage drop, high switching speed and high operating frequency, and is widely used in power electronics, electric vehicle control and other fields.