Comparison of power switch tube
The commonly used power switches include thyristor, IGBT, field effect tube and so on.Among them, thyristor (thyristor) has a minimum switching frequency of about 1,000 times a second, generally not applicable to the switching circuit of high frequency work.
（1）the effect of tube: the characteristics of the field effect tube advantage is its extremely high switch frequency, it can switch more than 500000 times per second, pressure generally in more than 500 v, 150 ℃ heat resistance (tube), and the conduction resistance, pipe, low loss, is the ideal switching devices, especially suitable for switching device used in high frequency circuit.But field effect tube working current is small, high of about 20 a low generally at about 9 a, limits the maximum current in the circuit, and as a result of the field effect tube packaging form, makes the creepage distance of the pin (conductive to the surface of the distance between a conductive body) is small, under the environment of high pressure easy to breakdown, makes conduction between pin and damage to the machine or endanger personal safety.
（2）IGBT is the bipolar insulation effect tube, and the switching frequency is between 20KHZ~ 30KHZ.But it can pass through the big current (100A), and because of the outer package lead foot space, the creepage distance is big, can resist the influence of environmental high pressure, safe and reliable.
The characteristics of the field effect tube inverter welder
Prominent advantages of the field effect tube, use effect tube make the inverter switching devices, can design high switch frequency, in order to improve the conversion efficiency and cost savings, make the welder to miniaturization, micromation and convenient use.But both arc welder and cutter, their working current is very big.The use of a field effect tube can not satisfy the current demand of the welding machine. In general, the output current of the welding machine power supply can be improved by using more than one parallel.This increases the cost and reduces the stability and reliability of the circuit.
The characteristics of IGBT welder
IGBT is used as an arc welding machine for inverter switching devices.As a result of the IGBT switching frequency is low, large current, welding machine used in the main transformer, filter, energy storage capacitor, reactor and other electronic devices are JiaoChang effect tube welding machine is different, not only increase the volume, all kinds of technical parameters are changed.