Hold-Up Time Analysis of a DC-Link Module With a Series Voltage Compensator

A dc-link module composed of dc-link capacitors and a series voltage compensator has been proposed. It has been verified that the module can reduce the dc-link capacitance to 10–20% while achieving a very low voltage ripple across its output terminals. This paper investigates the required dc-link capacitance when a certain period of hold-up time is considered. Trade-off design conditions are presented and the hold-up time is compared with the solution without the series voltage compensator. The analysis is crucial to power converters connected to critical loads when hold-up time is required. The theoretical predictions have been verified by experimental results