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CANADIAN INDUSTRY ONLINE - JANUARY 2012
WHAT IS AN E NHAN C E D
I NV E R T E R ?
The main problem with conven-
tional inverters is that they were
designed with the philosophy that
since sunlight is free, why spend
time and money designing an
inverter to capture all of it. There-
fore, conventional inverters wait
until the ‘raw’ DC voltage coming
from the PV panels is high enough
that it’s easy to convert it to AC.
An enhanced inverter is designed
with the philosophy that since we’re
going to all the expense and work of
building an expensive solar array,
why not capture as much energy as
possible. Therefore, an enhanced
inverter will ‘wake up’ at a much
lower DC voltage, and stay on longer.
What that means in practical
terms is that instead of waiting until
mid-morning to start gathering
energy, the enhanced inverter will
start sooner, keep gathering under
clouds, and wait until later in the
day to turn off. The end result is
that a properly designed solar array
with an enhanced inverter can
gather up to 30% more electricity
per year – significantly encouraging
investment, and pushing solar
electricity toward Grid Parity
The graph opposite illustrates the
difference between a conventional
inverter and an enhanced inverter.
•The DC power from the solar array (pale
yellow line) starts shortly after daylight, dips
when the clouds go over, rises toward noon, and
declines as evening falls.
•The conventional inverter (pink area)
waits until the DC voltage rises to about half
of the maximum, turns off again when clouds
reduce the DC voltage, and ‘goes to sleep’ in the
afternoon
•The enhanced inverter (blue area) starts to
work at a much lower DC voltage, so it can ‘ride
through’ cloud cover and work for more hours of
the day. Moreover, since its efficiency is higher,
it generates more energy even at times when the
conventional inverter is on. This greater yield is
replicated throughout the year, so the enhanced
inverter will gather electricity even during the
fall, winter, and spring, when conventional
inverters are largely ineffective.
Hourly Output
Midnight 6AM Noon 6PM Midnight
Insolation
Illumination at Ground
HPE Inverter
Conventional Inverter
DC Power Available
RENEWABLES - HYBRIDYNE