Hardswitching

Hardswitching refers to a method of operating electronic switches, such as transistors or thyristors, where the switch transitions from a fully conducting state to a fully blocking state, or vice-versa, while a significant amount of voltage and current are present across it simultaneously. This overlap of voltage and current causes power dissipation within the switching device, leading to energy loss in the form of heat. This power loss occurs during the switching transition, known as the switching interval.

In contrast to softswitching techniques, which aim to minimize or eliminate this voltage-current overlap by switching when either voltage or current is near zero, hardswitching inherently involves these simultaneous conditions. This results in higher switching losses and can lead to increased device stress and electromagnetic interference (EMI).

Hardswitching is commonly found in many power electronic converter topologies, especially older designs or applications where cost and simplicity are prioritized over efficiency. Examples include basic buck and boost converters operating at moderate frequencies. The limitations of hardswitching in terms of efficiency and thermal management often drive the adoption of more advanced softswitching strategies in high-power or high-frequency applications. The design of hardswitched converters requires careful consideration of thermal management to dissipate the heat generated during the switching process.