Functional division of electronic transformers

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Functional division of electronic transformers [Copy link]

Electronic transformers can be divided into two types from the functional point of view: transformers and inductors. The functions performed by special components are discussed separately.
Transformers perform three functions: power transmission, voltage conversion and insulation isolation. Inductors perform two functions:
power transmission and ripple suppression.
There are two ways of power transmission. The first is the transformer transmission method, that is, the alternating
voltage generates a flux change in the magnetic core, causing the secondary winding to induce voltage, which is applied to the load, thereby transmitting electric power from the primary side
to the secondary side. The size of the transmitted power is determined by the induced voltage, that is, it is determined by the flux density variable ΔB per unit time.
ΔB has nothing to do with the magnetic permeability, but is related to the saturation flux density Bs and the residual flux density Br. From the perspective of saturation flux density,
the order of Bs of various soft magnetic materials from large to small is: iron-cobalt alloy is 2.3-2.4T, silicon steel is 1.75-2.2T, iron-based
amorphous alloy is 1.25-1.75T, iron-based microcrystalline nanocrystalline alloy is 1.1-1.5T, iron-silicon-aluminum alloy is 1.0-1.6T, high magnetic
permeability iron-nickel permalloy is 0.8-1.6T, cobalt-based amorphous alloy is 0.5-1.4T, iron-aluminum alloy is 0.7-1.3T, iron-nickel-based
amorphous alloy is 0.4-0.7T, and manganese-zinc ferrite is 0.3-0.7T. As the core material of electronic transformers, silicon steel and iron-
based amorphous alloys are dominant, while manganese-zinc ferrite is at a disadvantage.
The second type of power transmission is the inductor transmission mode, that is, the electric energy input to the inductor winding excites the magnetic core,
converts it into magnetic energy and stores it, and then converts it into electric energy through demagnetization and releases it to the load. The size of the transmitted power is determined by
the energy storage of the inductor core, that is, it is determined by the inductance of the inductor. The inductance is not directly related to the saturation flux density, but to the magnetic permeability.
The higher the magnetic permeability, the larger the inductance, the more energy storage, and the larger the transmission power. The magnetic permeability of various soft magnetic materials is in the following order from large to small
: Ni80 Permalloy is (1.2~3)×106, Cobalt-based amorphous alloy is (1~1.5)×106, Iron-based microcrystalline nanocrystalline alloy is
(5~8)×105, Iron-based amorphous alloy is (2~5)×105, Ni50 Permalloy is (1~3)×105, Silicon steel is (2~9)×104, and
Manganese-zinc ferrite is (1~3)×104. As the core material of the inductor, Ni80 Permalloy, Cobalt-based amorphous alloy, and Fe-
based microcrystalline and nanocrystalline alloy are dominant, while silicon steel and manganese-zinc ferrite are at a disadvantage.

The size of the transmitted power is also related to the number of transmissions per unit time, that is, it is related to the operating frequency of the electronic transformer.
The higher the operating frequency, the greater the power transmitted under the same size of the core and coil parameters.
Voltage conversion is completed by the turns ratio of the primary winding and the secondary winding of the transformer. Regardless of the power transmission size,
the voltage conversion ratio of the primary side and the secondary side is equal to the turns ratio
of the primary winding and the secondary winding. Insulation isolation is completed by the insulation structure of the primary winding and the secondary winding of the transformer. The complexity of the insulation structure is related to the size of
the applied and transformed voltage. The higher the voltage, the more complex the insulation structure.
Ripple suppression is achieved through the self-inductance potential of the inductor. As long as the current passing through the inductor changes, the magnetic flux generated by the coil in
the magnetic core will also change, causing a self-inductance potential to appear at both ends of the coil of the inductor, and its direction
is opposite to the direction of the applied voltage, thereby preventing the change of current. The frequency of ripple change is higher than the fundamental frequency, and the current frequency of current ripple is larger than the fundamental frequency,
so it can be more suppressed by the self-inductance potential generated by the inductor.
The ability of the inductor to suppress ripple is determined by the size of the self-inductance potential, that is, the size of the inductance, which is
related to the magnetic permeability of the magnetic core. Ni80 Permalloy, Cobalt-based Amorphous Alloy, and Iron-based Microcrystalline Nanocrystalline Alloy have high magnetic permeability and are at an advantage, while
Silicon Steel and Manganese-zinc Ferrite have low magnetic permeability and are at a disadvantage.