Two ways to change the inductance size in a power supply
1： The method is to use a soft magnetic ferrite with threads to change the position of the iron core in the coil;
2： Using a sliding switch to change the number of coil turns, thereby altering the inductance of the inductor. The disadvantage of these two methods is that they have movable parts that can only be manually adjusted and cannot be automatically controlled. In specific power equipment, the method of combining iron core and circuit is used to change the inductance size of the inductor. There are three methods as follows.
a: Saturation inductance method
Wrap two windings on the iron core, one is the working winding, which is connected to AC; The other is to control the winding by passing DC and changing the magnitude of the DC current in the control winding, which can alter the saturation level of the iron core and thus change the equivalent inductance of the working winding. This method is relatively early, and the working principle of saturated inductors and magnetic amplifiers is based on this saturated inductance method.
b: Switch controlled inductance method
Connect a bidirectional thyristor switch in series in an inductor circuit, and change the equivalent inductance of the inductor by the conduction and turn off of the bidirectional thyristor. A large number of research, development, and production of sine energy divider type AC stabilized power supplies at home and abroad are based on this switch controlled inductance method.
c: Orthogonal iron core control inductance method
Rotate half of the C-type iron core by 90 ° and connect it to the other half. Wrap the working winding around the other half of the iron core and connect it to AC power; The other half of the iron core is wound with a control winding; Direct current is used. By changing the magnitude of the DC current, the inductance of the working winding can be continuously adjusted,. Applied in switching power supplies, inverters, AC stabilized power supplies, and power AC series compensators and phase shifters. Japan calls this type of orthogonal shaped soft ferrite iron core SX type iron core.
