virtaushäviön

Virtaushäviö is a Finnish term used in electrical engineering to describe energy that is lost as electric current flows through a circuit, device, or system. In practice, virtaushäviö refers to all losses associated with the presence of current, which reduce the overall efficiency of power transmission, conversion, or use. The concept appears across fields such as power electronics, transformers, motors, and distribution networks, and the precise components included can vary by context.

Common components of virtaushäviö include resistive (I^2R) losses in conductors, skin and proximity effects that raise the effective resistance at higher frequencies, and core losses in magnetic materials such as hysteresis and eddy currents. Switching losses in power electronic devices—energy dissipated during the on/off transitions—also contribute to virtaushäviö. In some designs, additional losses related to dielectric heating or parasitic elements may be considered part of virtaushäviö.

Calculating virtaushäviö typically involves component-level models. Ohmic losses follow P = I^2R, with R increasing due to skin effect at higher frequencies. Core losses depend on material properties and the magnetic flux, and switching losses depend on switching frequency, device capacitances, and drive waveforms. Engineers estimate virtaushäviö from predicted input and output powers, from hardware datasheets, or through simulations such as finite-element analysis.

Minimizing virtaushäviö is central to improving efficiency. Strategies include using low-resistance conductors and larger cross-sections, effective cooling, laminated or high-quality magnetic cores to reduce core losses, and power-electronic designs that lower switching energy, such as soft-switching techniques and optimized switching frequencies. Understanding virtaushäviö is essential for designing efficient electrical systems.