Currentförluster

Currentförluster, or current losses, are unwanted losses of electrical energy that occur when electric current flows through conductive or magnetic materials. They appear as heat, and in alternating current systems can also manifest as radiation or acoustic noise. The most common form is resistive or copper loss: P = I^2 R, where I is the current and R the resistance. Higher currents or higher resistivity increase losses. Skin effect, proximity effect, and temperature raise the effective resistance at higher frequencies, increasing losses in conductors and bus bars.

Another major category is core losses in magnetic components such as transformers and inductors, comprising hysteresis losses from magnetic domain realignment and eddy current losses from induced circulating currents in the core. In power electronics, switching losses arise from non-ideal transitions of semiconductor switches, while switching frequency and device characteristics determine their magnitude.

Dielectric losses in insulating materials and cables with alternating current, as well as stray losses from insulation and housings, can contribute in high-frequency or high-voltage systems. Other minor loss mechanisms include radiation losses in high-frequency equipment and mechanical vibrations caused by magnetostriction in some devices.

Mitigation strategies include using larger conductor cross-sections or more conductive materials, efficient cooling, laminated or grain-oriented cores to reduce eddy currents, employing litz wire to minimize skin effect, careful electrical layout to minimize stray inductances, and selecting switching techniques and frequencies that balance performance with efficiency.

Currentförluster are a key consideration in power transmission, electric machines, data centers, and battery systems, where reducing losses improves overall efficiency and lowers thermal management requirements.