www.vicorpower.com/ HIGH-VOLTAGE-TO-48V POWER CONVERSION 13 www.power-mag.com Issue 2 2024 Power Electronics Europe consumed by power conversion losses. If high-voltage distribution to the rack saves just 1% of this power conversion (a conservative estimate), then for a 1GW system, it represents a savings of 10MW. At $50 per MW/hr x 8,760hr/yr, this is $438k OPEX savings per year. Depending on the source of the energy, this is also a substantial reduction of greenhouse gases. Using natural gas power generation for comparison, 10MW produces about 4,000kg of CO 2 per hour or 35Mkg per year. Technical considerations for high-voltage DC High-voltage conductors are often identified (to technicians and first responders) with orange insulation for safety reasons. This can be easily observed in electric vehicles. High voltage sources must be galvanically isolated for human and system safety; isolation also eliminates ground loops and reduces noise. This is critically important. The isolation should be 2x to 4x working voltage isolation (conservatively 3.2kV for 800V applications). Other challenges with high-voltage DC includes providing sufficient creepage (the shortest distance along the surface of an insulator between two conductors) and clearance (the shortest distance through the air between two conductors) for electrical safety concerns such as electric shock, fires and equipment failure. This applies both to discretely-implemented solutions and modular solutions. Insufficient creepage or clearance can cause arcing, shorts and breakdowns, particularly at high voltages and as environmental Figure 3 Right: Creepage and clearance requirements are international safety measures to mitigate the risk of arcing. Lack of proper distancing may result in excess heat, directly damaging or compromising the power delivery network. Higher voltage requires up to 60% greater space in between components, a specification at odds with designing for a smaller power delivery footprint. Figure 4 Left: There are 11 important requirements to keep in mind when designinig a power delivery network that is converting high voltage to a 48V bus.
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