Koppelomvormers

Koppelomvormers, in Dutch, refer to a class of power electronic converters designed to transfer energy between two electrical domains while providing controlled coupling. They typically combine semiconductor switching devices with a transformer or tightly coupled inductors, enabling galvanic isolation and voltage transformation between the input and output sides. The energy transfer can be bidirectional and can be implemented in DC-DC, AC-DC, or AC-AC configurations, depending on the application.

Working principle: The converter switches the devices to regulate the magnitude and phase of the voltage and current on the output side, while the transformer or magnetic coupling sets the voltage ratio and provides isolation. Common control strategies include pulse-width modulation and phase-shift control to manage active and reactive power.

Architectures: Isolated koppelomvormers use a transformer to satisfy isolation requirements; non-isolated variants rely on strong magnetic coupling for energy transfer. A well-known example is the dual-active-bridge (DAB) converter, used for bidirectional DC-DC links in battery storage and EV charging. In AC domains, koppelomvormers can realize AC-AC conversion with isolation.

Applications: Renewable energy interfacing (PV, wind) to DC buses, battery storage and vehicle-to-grid systems, back-to-back interfaces in data centers and grids, and motor drives requiring galvanic isolation.

Advantages and challenges: Benefits include bidirectional power flow, galvanic isolation, and flexible voltage scaling. Challenges involve switching losses, electromagnetic interference, thermal management, and the complexity of control and magnetics design.

Terminology: The Dutch term encompasses several coupled-converter concepts; depending on context, references may specify isolated DC-DC, AC-AC, or bidirectional structures.