Improved thyristor switching using a ferrite element

Experiments were performed to demonstrate lower switching-power dissipation in thyristors by using novel methods of obtaining more turned-on area in the devices. This was done by using very large gate currents to trigger the devices and by using a saturable magnetic component in series with the thyristors. The large gate signals turned on more of the cathode region and the saturable component allowed time for more lateral spreading of the conducting region once the thyristors were triggered. When thyristors are triggered into conduction, the voltage across them collapses and is transferred to the magnetic material. The domains in the material begin to align according to the small magnetizing current flowing. Most of the domains align after a short period of time, so that this saturation of the material (switching) allows the thyristors time to turn on more completely. As the voltage collapses across the saturable material the current rises quickly to its peak to complete the closing of the switch. Voltage and current switching waveforms are shown, and the associated power dissipation is calculated