Power transformer toroid Design

[MohamedSaleh]

I'm working on induction furnace project,, I'm facing a serious problem with my toroid transformer. As you may find in the attachment Pic, There's green toroid with 20 Turns, which transfer the current from 1500 Hz inverter to LC tank which in turn works in resonance. The problem is the core saturates before I reach the current level I need ( which 40 amps) as you may also find in the attachment file. It saturates at 3 amps. I'm seeking for help to design the core so that it doesn't saturate at the current level I need



the yellow waveform is the output voltage of the inverter,, the blue waveform is the output current , as u can see the spike happens like that at certain voltage level ,, but at lower voltage level ,, the output current is pretty much sinusoidal wave until I increase the voltage and current spikes up

[Experimentonomen]

At that low frequency you need alot more turns. I built a induction heater using the core from a 3.5kW smps, the thing ran at ~30kHz and had a primary of around 20 turns.

Primary current peaked at around 60A and secondary current was in the hundreds of Amps.

Some pics of my project: http://imgur.com/a/AxfCU

A  video:

Making some aluminum brass:

[megajocke]

I'm working on induction furnace project,, I'm facing a serious problem with my toroid transformer. As you may find in the attachment Pic, There's green toroid with 20 Turns, which transfer the current from 1500 Hz inverter to LC tank which in turn works in resonance. The problem is the core saturates before I reach the current level I need ( which 40 amps) as you may also find in the attachment file. It saturates at 3 amps. I'm seeking for help to design the core so that it doesn't saturate at the current level I need

Assuming it is the resonant circuit current you want to increase, you need to increase its drive voltage coming from the secondary of this transformer. So you need to increase the number of transformer secondary turns, increase the core cross sectional area and/or use a core material with higher saturation flux density to allow a higher secondary voltage without saturation.

Changing the number of primary turns will not change the LC tank drive voltage (and hence current) at which the transformer saturates, but only the primary parameters at this point.

You should start by determining how much drive voltage and current the LC tank needs and design your transformer based on that (the transformer secondary parameters).