IEEE Power Electronics Magazine - December 2019 - 66

ma ker s, a nd t hose i nvolved i n
deployment. In other words, all
those things streaming videos or
under real-time control (such as an
industrial robot) may be consuming
& 90% of the network traffic, but
they represent %5% of the number of
devices (nodes, motes, things, and
so on) deployed on global networks.
Since >95% of them are low bandwidth and high latency, it is actually
these relatively "slow" and "simple"

receives these power "packets" and
multiply that by the many billions and
even trillions of devices on the edge.
Fundamentally, this simple analysis shows how the sheer number of
edge devices (regardless of their
bandwidth requirements) plays a
much bigger role in impacting the
PVC and localized utility grid than
the high-bandwidth, low-latency
devices that seem to be the focus of
most network architects, equipment

devices (typically of the ultralowpower variety) that are truly determining the fate of 5G. This is the primary reason why energy harvesting
technologies are a critical enabler
for driving corrective action to this
network-failure analysis [2]. Supplementing a relatively tiny bit of energy at the edge has the effective benefit of saving six or more orders of
magnitude worth of power at the
generating plant.

Note: Percentages represent the efficiency
loss due to the power conversion stage.

Power
Plant

Step-Up
Transformer
(~1-2%) Transmission
(~2-4% Total)

Step-Down
Distribution
Transformer
Network
Transmission (~4-6%)
(~1-2%)

=

You have lost ~8-15% of
your power just getting from
the power plant to your door.
Efficiency for This Stage = ~92%
(Best Case)

(Neglecting Plant Conversion Efficiency...<<50%)
Source: International Electrotechnical Commission

Building
(HV in)

ac/dc

IT
Equipment

dc/ac

=

Efficiency for This Stage = ~95%
(Best Case)

Battery/UPS (~5-10% Total)
Server Example (ac Input)
Front End
ac/dc
(~5-15%)

ISO dc/dc
(~2-4%)

NON-ISO
dc/dc A
(~5-10%)

NON-ISO
dc/dc B
(~4-8%)

Load
(such as
a CPU)

=

Base Station Example
Overhead
(~10-20%)

BBU
(~20-30%)

Power Amp
(~80-90%)

Tx Antenna
(~50%)

You have lost ~15-32% of
your power getting from
the system input to the load.
Efficiency for This Stage = ~85%
(Best Case)

Potentially Improved
by Combining in the Front End

Power
(~20-15%)

You have lost ~5-10% of
your power just getting from
the door to your system.

=

You have lost ~94-98% of
your power getting from the
grid to the transmitting antenna.
Efficiency for This Stage = ~6%
(Best Case)

(Combined Power Solution
and Cooling)

=

You have lost ~99.9% of
your power transmitting from
the base station to the smartphone.
Efficiency for This Stage = ~0.1%
(Best Case)

FIG 2 The PVC component efficiencies (worst to best estimates) at each stage. Amp: amplifier; HV: high voltage; ISO: International
Organization for Standardization; Tx: transmitter. (Source: PowerRox; used with permission.)

66

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