Power Supply Efficiency Comparison at 380VDC versus 230VAC

Overview

This document is a Green Grid presentation dated 24 May 2021, presented by Jason Boehlke and Colleen Collins. Its purpose is to determine whether separate test criteria are warranted for 380 V DC server power supplies (PSUs).

The method is simple: data from roughly 30 units, each tested at both 230 V AC and 380 V DC. Because the same units are compared, their efficiencies can be set side by side directly, and noise from differences between units is reduced. The framework gives measured context to claims about the efficiency of DC distribution. The roughly 30-unit sample gives a more dependable context than inference from a single device, though its size and scope are limited to what the summary page states.

As a presentation it is a short source, and the landing page does not give numerical results. This page therefore claims no particular efficiency difference. The document should be read as context for not assuming a large PSU efficiency gain at 380 V DC compared with 230 V AC. It does not weigh every advantage and drawback of DC distribution; it addresses only the power-supply efficiency dimension.

Key points

1. Presentation dated 24 May 2021 by Jason Boehlke and Colleen Collins.
2. Purpose: determine whether test criteria for 380 V DC PSUs are warranted.
3. Data from roughly 30 units.
4. Each unit tested at both 230 V AC and 380 V DC.
5. Comparing identical units removes differences between units from the measurement.
6. The public summary gives no numerical results.

Using it in design

• In AC-vs-DC comparisons, do not assume a large PSU efficiency gain at 380 V DC.
• Model PSU efficiency as an input with a default similar to high-line AC unless the user supplies measured data.
• Back efficiency arguments for DC distribution proposals with measured data.
• State the PSU models and test conditions in the comparison report.

Who should read it

Electrical design engineers comparing AC and DC power distribution, and teams selecting IT power supplies.

Publication details

Authors

Jason Boehlke; Colleen Collins

Publisher

The Green Grid

Year

2021

Document language

English

Source type

Industry body

Access

Citation only

Licence

Copyright retained; citation only — the publisher’s terms apply to the original document

Citation