Unlike copper loss, the iron loss of the transformer has nothing to do with factors such as winding and current size, as the name suggests, the iron loss is related to iron, which is generated by the iron core. The iron loss of the transformer is also called "no-load loss", because it exists in the full load and zero load state of the transformer, and is a fixed loss of the transformer. However, in the load, the power loss will decrease with the decrease of the electric field strength.
The iron loss of transformer can be divided into hysteresis loss and eddy current loss.
Hysteresis Loss
The working principle of the transformer is based on the principle of electromagnetic induction to achieve the rise and fall voltage and current changes, and the magnetic flux in the transformer is flowing on the iron core, the iron core has a magnetic resistance to the magnetic flux, just like the conductor has a resistance to the current, it will also generate heat, such a loss is called "hysteresis loss".
Eddy Current Loss
When the primary winding of the transformer is energized, the magnetic flux generated by the coil flows in the core, because the core itself is also a conductor, in the plane perpendicular to the magnetic force line will induction potential, this potential forms a closed loop on the cross section of the core and generates current, like a vortex, so it is called "vortex". The loss caused by this eddy current is called "eddy current loss". It is also because the iron core creates eddy currents that it is made into a thin piece, because the thinner the resistance, the lower the current.
Influencing Factor
1. Operating voltage and frequency: Iron loss is related to the operating voltage and frequency of the transformer, because these factors affect the magnetic field strength and hysteresis in the iron core.
2. Core material: The hysteresis properties of the core material will affect the size of the iron loss. If the core material is not selected well, the hysteresis loss will increase.
3. Manufacturing process: The manufacturing process of the transformer also has a certain impact on the iron loss. For example, the lamination method of the iron core, insulation treatment, etc., will affect the size of the iron loss.
Formula Mode
1. iron loss(unit:kVA) = I² × (Rm + Ra), I is the rated current of the transformer, Rm is the hysteresis loss of the iron core, and Ra is the resistance loss of the iron core.
2. iron loss(unit:kVA) = Kf × (Bm)^2 × f, Kf is a constant, Bm is the flux density, and f is the transformer operating frequency.
Reduction method
1. Select high-quality core materials: Select core materials with small hysteresis loss, which can reduce the iron loss of the transformer.
2. Optimize the manufacturing process: reduce the iron loss by improving the lamination method of the iron core, insulation treatment and other manufacturing processes.
3. Reasonable design: In the transformer design stage, by optimizing the structural design and parameter selection, reduce the iron loss.
