IGBT（Insulated Gate Bipolar Transistor), the abbreviation of IGBT is composed of MOSFET and Bipolar Transistor composite of a device, its input is  MOSFET, output is PNP Transistor, it have the advantages of these two kinds of devices, has both MOSFET device driving the advantages of small power and fast switching speed, but also has low saturation voltage Bipolar devices and the advantages of large capacity, its frequency characteristic between MOSFET and power Transistor,It can work normally within the frequency range of tens of kHz, and it has been widely used in modern power electronics technology, and occupies a dominant position in large and medium power applications of higher frequencies.As a new type of power semiconductor field-controlled self-closing device, it integrates the high-speed performance of power MOSFET with the low resistance of bipolar device, and has the characteristics of high input impedance, low voltage control power consumption, simple control circuit, high voltage resistance and large current bearing. It has been widely used in various power transformations.