Views: 0 Author: Site Editor Publish Time: 2024-12-30 Origin: Site
The loss of power transformer mainly includes copper loss and iron loss. This is because any electrical equipment will produce losses during a long period of operation, and power transformers are no exception.
Unlike copper loss, the iron loss of a transformer is independent of factors such as winding and current size. From the name point of view, iron damage is closely related to iron, it is produced by the iron core. The iron loss of the transformer is also known as "no-load loss", which is because the iron loss always exists in the transformer, whether it is full load or zero load, and belongs to a fixed loss of the transformer. However, during the load process, the power loss will decrease with the decrease of the electric field strength.
The iron loss of the transformer is divided into hysteresis loss and eddy current loss.
The working principle of the transformer is based on the principle of electromagnetic induction to achieve voltage rise and fall and current changes. The magnetic flux in the transformer flows on the iron core. The iron core has magnetic resistance to the magnetic flux, just like a conductor has resistance to current. Similarly, heat will also be generated, and this loss is called "hysteresis loss".
When a current is applied to the primary winding of the transformer, the magnetic flux generated by the coil flows in the iron core. Because the core itself is a conductor, an electric potential is induced in a plane perpendicular to the magnetic field line. This potential creates a closed loop in the cross section of the core, which in turn generates an electric current. This current acts like a rotating vortex, hence the name "vortex". The loss caused by eddy current is called "eddy current loss". It is because the core creates eddy currents that it is made into a thin sheet. Because the thinner the core, the higher the resistance, the lower the current.
• Operating voltage and frequency: Iron losses are related to the operating voltage and frequency of the transformer because these factors affect the magnetic field strength and hysteresis in the core.
• Core material: The hysteresis properties of the core material will affect the magnitude of the iron loss. If the core material is not selected well, hysteresis loss will increase.
• Manufacturing process: The manufacturing process of the transformer also has a certain impact on the iron loss. For example, the core lamination method, insulation treatment, etc. will affect the size of the iron loss.
• Select high-quality iron core material: Selecting iron core material with small hysteresis loss can reduce the iron loss of the transformer.
• Optimize the manufacturing process: Reduce iron loss by improving the core lamination method, insulation treatment and other manufacturing processes.
• Reasonable design: In the transformer design stage, iron losses are reduced by optimizing structural design and parameter selection.
Copper plays an important role in transformers. Copper wires are usually used in the windings of transformers. The "copper loss" in the transformer is the loss caused by the copper wires. The "copper loss" of the transformer is also called load loss. The so-called load loss is variable loss and changes.
It changes with the change of current, copper loss (load loss) is a variable loss, and it is also the main loss in transformer operation.
• Current size: As mentioned above, copper loss is proportional to the square of the current, so the size of the current is the key factor affecting copper loss.
• Winding resistance: The resistance of the winding directly affects the copper loss. The greater the resistance, the higher the copper loss.
• Number of coil layers: The more coil layers there are, the longer the path for current to flow in the winding, and the resistance will increase accordingly, resulting in increased copper loss.
• Switching frequency: The effect of switching frequency on transformer copper loss is directly related to the distribution parameters and load characteristics of the transformer. When the load characteristics and distribution parameters are inductive, the copper loss decreases as the switching frequency increases; when they are capacitive, the copper loss increases as the switching frequency increases.
• Temperature influence: Load loss is also affected by the temperature of the transformer. At the same time, the leakage flux caused by the load current will produce eddy current losses in the winding and stray losses in the metal parts outside the winding.
• Increase the winding cross-sectional area of the transformer: reduce the conductor resistance, thereby effectively reducing the copper loss of the transformer.
• Use high-quality conductor materials: such as copper foil or aluminum foil to reduce winding resistance.
• Reduce the light-load operation time of the transformer: Limiting the proportion of light-load operation time of the transformer will help reduce the copper loss of the transformer.
