Induction heating power supply selecting main circuit form and analysis

Induction heating power supply has been widely used in metal smelting, welding, tube bending, surface quenching heating and the heat treatment industry. For different artifacts and technology, insist on the power of the different work frequency and output power. Induction heating power supply according to its working frequency divided into 400 hz to 10 KHZ thyristor ( 可控硅) Type semiconductor medium frequency power supply and a 100 hz 400 kh electron tube high frequency heating power supply. This article mentioned the medium frequency induction heating power supply using IGBT as the switch device, can work in 10 hz to 10 KHZ frequency band. It makes full use of intermediate frequency skin effect and proximity effect and circle effect principle, through induction, the electrical energy into heat energy effectively, so as to achieve the goal of high efficiency and energy saving. 1 main circuit. 1 plan selection form a lot of induction heating power supply circuit, its selection is based on: 1) Adopts the series resonant inverter for induction heating device are mainly parallel resonant inverter ( Current inverter) And series resonance ( Voltage inverter) Two kinds of forms. During the converter and parallel resonant inverter of inverter switch devices may inherit the reverse voltage, and the IGBT is cannot bear reverse voltage. If using the parallel fast diode protected and damage of circulation device will appear. As a result, each bridge arm must be same as switching device voltage series of advantages such as fast recovery rectifier diode, to withstand reverse voltage. However, this will increase each arm state loss, at the same time increase the cost of equipment. In addition, due to the high frequency, using parallel resonant inverter, between the resonant capacitor and heating coil wire shoulds not be too long, otherwise it will seriously affect the power output and efficiency. This for series resonant inverter, lead longer, will only change the working frequency and minimal impact on output frequency and efficiency. 2) Using single tube IGBT module as the switching device in power semiconductor devices, IGBT switching speed can meet the requirements of below 50 KHZ induction heating power supply. It has a high input impedance, small driving power, the loss of state and a series of advantages. 3) Use transformer coupling output three-phase 380 v power supply of single phase inverter bridge, the output voltage up to 530 v, if direct output, the resonant capacitor and the output voltage is the voltage on the heating coil of Q ( Q value with load is different, can change the range 3 ~ 15. ) , made on the heating coil voltage is too high, and antihypertensive measures must be taken. Moreover, high voltage capacitor can also be difficult to solve. 4) Using PWM control mode adjustment the output power of series resonant inverter power adjustment way has two kinds, one is the change of dc voltage; The second is to change the power factor. The former can be according to the load situation, given the corresponding frequency, make the inverter work always in the state of the power factor to 1. By changing the dc voltage to adjust output power. Although the circuit of inverter switch tube on the surge voltage and surge current request is not high, at the same time the power factor of inverter often work at higher state, through the little reactive current of IGBT module, the IGBT. With the method of the change of power factor regulating the output power. Specific methods first adjust output frequency make the system work near the resonance state, then adjust the PWM pulse width, to the required output power' See who else in WTR bearing 】 : zhejiang hailiang CheJiaXing cement China wind power in China's hubei province is fitting click to see more customer case! The above articles from jiaxing Kurt automation equipment co. , LTD ( ） Reprint please indicate the source