A Comprehensive Review on Partial Power Processing-based Voltage Regulator Modules for 48-V Bus-based Data Centers

Nowadays, the data center is becoming a large consumer in the electricity market with the blooming of information and communication technologies. To ensure the chip-level power supply, the electric power from the utility must step down to the desired very-low voltage domains, leading to considerable losses in cascaded power conversions. As the interface between the bus bar and load elements, high-performance voltage regulation modules (VRMs) are the cornerstone of greener data centers. Hence, along with the development of power electronics technologies, various converters have been presented in the literature. One of the key issues for data centers is to maintain the voltage balance with high efficiency. In this paper, state-of-the-art partial power processing (PPP)-based VRMs are systematically analyzed and reviewed. Then, a comparative simulation between different control objectives is carried out with four series-connected loads. The results showed that the difference in control objectives will influence both the total and the unit-maximum processing power of the PPP-based system. Additionally, the challenges for future data centers are briefly discussed.