I. Introduction
In the past decade, electrical energy demand has been extremely boosted in various applications due to rapid advancement in their technologies. Hence, the electric power conversion ability should keep up with the rising need in all kinds of electric power conversion applications, (i.e., dc-dc, dc-ac, ac-dc, and ac-ac). The electrical energy requirement of data centers and electric vehicles (EVs) has significantly increased because of the fast development of cloud computing and energy storage technologies, respectively. With the technological development of power electronics circuits, more reliable electric energy will be delivered to consumer loads [1]–[6]. LLC resonant converters are widely used in many industrial applications due to their interesting characteristics such as zero-voltage switching (ZVS) for primary-side switches and zero-current switching for secondary side diodes/switches. In datacenter power processing and EV auxiliary low voltage onboard battery charger applications, it is needed for the dc-dc stage to operate in a wide input voltage range, (e.g., ∼250 to ∼400 V) to enhance the availability of power at the low voltage dc bus, (e.g., 12–14 V) for a longer time.