There are two main types of induction melting furnaces   at home and abroad . Parallel inverter induction melting furnaces and inverter series induction melting furnaces have generally produced parallel resonant types because they cannot produce high-voltage resonant electric heating capacitors and high-power high-voltage thyristors.

Induction melting furnace , in recent years, is now due to components has been a breakthrough in technology, system manufacturers are developing electric tandem-type electric furnace.

    Parallel inverter is current type resonance (a) The current I in the oscillation circuit is Q times the power supply current i

Q is a loop quality factor, usually up to 6 or more, so the current I is large in the resonant circuit, and the load coil L, the capacitor C, and the copper row have a large heat loss.

    The series inverter is a voltage type resonance (b), the current in the circuit is equal to the current supplied by the power supply, and the electricity is

The oscillating voltage on the capacitor C and the load coil is Q times the supply voltage and can be as high as 2 500 volts or more.

Since the resonant tank current I is equal to the supply current i through the thyristor. Therefore, series inverter is more parallel inverter

The power loss in the loop is much smaller, so the electrical efficiency of the series inverter furnace is much higher than that of the parallel inverter circuit.

  When the series induction melting furnace is working, the rectification always works under the condition of full conduction. Changing the output power of the inverter circuit is realized by controlling the inverter trigger pulse frequency. And the load current is sine wave, so the series inverter power supply

There will be no high-order harmonics that seriously pollute the power grid and have a high power factor. Parallel inverter is impossible to achieve

Dynamic power adjustment operation, because parallel inverter power supply adjustment can only be achieved by adjusting the rectifier bridge output voltage, when parallel

When the inverter rectifier bridge works at a low voltage and the rectification conduction angle is small, the power factor of the device will be very low.

And the parallel inverter load current is a square wave, which will seriously pollute the power grid. If you adjust the inverter back pressure angle to adjust the power,

The range of power adjustment is very narrow

Parallel and series resonant inverter comparison