Two ways to change the size of inductance in power supply
There are usually two ways to change the size of the inductance in the power supply.
One: The method is to use threaded soft ferrite to change the position of the core in the coil;
Two: Use a slide switch to change the number of turns of the coil, thereby changing the inductance of the inductor. The disadvantage of these two methods is that there are movable parts, which can only be adjusted manually and cannot be controlled automatically. In the specific power supply equipment, the method of combining the iron core and the line is used to change the inductance of the inductor. There are the following three methods.
a: Saturated inductance method
Two windings are wound on the iron core, one is the working winding, which communicates with AC; the other is the control winding, which communicates with DC, and changing the magnitude of the DC current in the control winding can change the saturation degree of the core, thereby changing the equivalent inductance of the working winding size. This method is relatively early, and the working principle of saturated inductors and magnetic amplifiers is based on this saturated inductance method.
b: switch control inductance method
A bidirectional thyristor switch is connected in series in the inductor circuit, and the equivalent inductance of the inductor is changed by turning on and off the bidirectional thyristor. A large number of sinusoidal energy distributor-type AC regulated power supplies researched, developed and produced at home and abroad are based on this switch-controlled inductance method.
c: Orthogonal core control inductance method
Rotate one half of the C-shaped iron core by 90° and connect it with the other half, wind the working winding on one half of the iron core to communicate with AC; wind the control winding on the other half of the iron core to communicate with DC. Changing the size of the DC current can continuously change the inductance of the working winding. It is used in switching power supply, inverter power supply, AC regulated power supply and electric AC series compensator and phase shifter. Japan calls this kind of orthogonal shape soft ferrite core, called SX core.
