HVDC Power Architecture

Overview

HVDC (High Voltage DC) Power Architecture refers to the use of high-voltage direct current distribution -- typically at 800V or +/-400V -- within data center facilities as a replacement for conventional AC power distribution to server racks. In a traditional data center, utility power undergoes multiple AC-to-AC and AC-to-DC conversion stages (substation, UPS, PDU, rack PSU), each introducing efficiency losses and requiring physical space. HVDC architectures eliminate several of these conversion stages by distributing DC power at higher voltages directly to racks, where a single DC-to-DC step down to 48V or 4-12V serves the compute hardware. The result is higher end-to-end efficiency, reduced component count, and critically, reclaimed physical space within the rack that can be allocated to additional GPU compute.

The motivation for HVDC has shifted over the past several years. Originally proposed primarily for efficiency gains, it is now driven by the space reclamation argument: as AI accelerator racks scale toward megawatt-class power densities, the volume occupied by AC-to-DC power supply units inside the rack becomes a significant constraint on compute density. Disaggregating power conversion from the IT rack into sidecar racks or facility-level systems (like Solid-State Transformers) operating at HVDC voltages frees rack space for additional GPUs. Texas Instruments presented a 30 kW HVDC reference design (PMP23630) at 98.5% peak efficiency using a Flying Capacitor PFC topology at 65 kHz/phase, demonstrating that the enabling power electronics are reaching commercial maturity. The OCP Power sub-project, launched at the 2025 summit with co-leads from Google, NVIDIA, Microsoft, and Meta, has HVDC as one of its three primary workstreams alongside BESS and SST, with +/-400V and 800V architecture standardization as an immediate priority.