A way of switching power supply is the magnetic control type power switch. It is the use of multiple output converter cross regulator and can be combined together in a saturated reactor. The circuit structure of the way, compared with the loss or chopper, has the following characteristics:
1, low loss.
2, less components.
3, strong.
4, low noise.
In the past, magnetron type switch power supply of the saturable reactor mainly uses the slope of Dien alloy, but the core problem of temperature rise, to the high frequency. However, it is clear, amorphous core as high-frequency saturable reactor shows excellent properties, with the characteristics of nano magnetic control type switching power supply to be recognized, the demand is rapidly expanding. Therefore, allowable temperature rise must play to consider switching power supply using ambient temperature, internal heating and aluminum electrolytic capacitor life.
According to the above conditions, can the core saturation reactor should have the following characteristics of saturated magnetic flux density and residual magnetic flux density ratio for switching power supply, namely the squareness ratio.
1, small coercive force.
2, high saturation flux density.
3, good temperature characteristic.
Now, as the core of the saturable reactor, several known are shown in Table 3, the existing problems in the point of ferrite, and 80%Ni - Fc permalloy in the point problems, so are not used for high frequency switching power supply. Therefore the 50g6Ni - Fe for permalloy and Co based amorphous magnetic materials were studied, according to the characteristics and temperature on nourishing rectangular driven rise of measurement results, according to the output of guarantee and the allowable temperature condition, obtained the best frequency of saturable reactor is suitable for miniaturization. The relationship between the number of volume and the secondary coil of the transformer voltage in frequency, variable reactor. If the core dimensions are the same, then the volume is less, more small saturable reactor. So the best frequency of 50%Ni - Fc and Co - based amorphous magnetic materials are 20kHz and 100kHz. However, in 50%Ni - Fe case, because the volume number 46T from copper loss problems, the requirements of actual size is two times that..
So if the use of Co based amorphous magnetic materials can work in high frequency, the main element can be miniaturized. Co based amorphous magnetic materials as high-frequency saturable reactor shows excellent properties, but as mentioned before, if not aging changes to take countermeasures, in use process properties, core loss increases. Further increases in iron loss caused by temperature rise, the state has also increased the vicious spiral iron loss. Co based amorphous magnetic material rectangular ratio is small, but the existence of this tendency, so we must pay attention to.