DCLink

DCLink, short for DC link or DC bus, is the direct-current path in many power-electronic converters that connects the output of a rectifier to the input of an inverter. It acts as an intermediate, energy-storing stage and is typically implemented as a capacitor bank, sometimes supplemented by inductors and protection devices. The term is often used interchangeably with DC bus.

In practical designs, the DC link consists primarily of high-voltage capacitors rated for the system voltage; capacitors may be arranged in series to achieve the needed voltage rating with balancing resistors. Additional components such as smoothing inductors, contactors, fuses, and monitoring circuits may be included. The capacitance and voltage rating determine how much energy the DC link can store and how well it sustains voltage during switching.

Function: The DC link smooths the pulsating DC produced by rectifiers and provides instantaneous current for the inverter during switching, reducing voltage ripple and enabling stable AC output. In some configurations, the DC link supports bidirectional power flow and provides fault isolation in back-to-back or HVDC architectures.

Design considerations: Key factors include voltage rating (often several hundred to thousands of volts), total stored energy (E = 1/2 C V^2), equivalent series resistance and inductance, thermal management, reliability, and fault protection. Capacitor aging, temperature derating, and balancing of series-connected capacitors are important.

Applications: DC links are found in variable-frequency drives, motor drives, renewable-energy inverters, and high-voltage direct current transmission systems. The term may also refer to brand names or products in some contexts, but in general it denotes the DC intermediate circuit of power-electronic converters.