The present invention relates to a power supply apparatus
for electrical and/or electronic user devices.
It is known that uninterruptible power supplies or UPSs
are apparatuses capable of supplying electric power to connected user devices (output
loads) when the main power supply line fails.
These apparatuses in practice are connected electrically
to two separate and distinct power sources: on one side, the ordinary electrical
mains and, on the other side, one or more batteries arranged in a series or parallel
However, known uninterruptible power supplies draw the
power required by user devices from only one of these power sources and in particular
from the electrical mains in normal operating conditions and from the batteries
in emergency conditions.
The occurrence of these emergency conditions is often due
to the fact that the ordinary electrical mains has supply limitations dictated by
the user contracts, by the sizing of the supply facilities, and by the maximum power
that can be delivered to a geographical area by the provider (ENEL).
These limitations, for example, prescribe that the absorbed
power for home users is lower than 3.2 kW; exceeding this level entails the payment
of higher rates by the user and in some cases entails disconnection due to overload
of the mains supply and the beginning of the supply of power on the part of the
These traditional types of apparatus are not free from
drawbacks, including the fact that in emergency conditions they are unable to supply
a particularly large amount of energy for a very long and continuous period of time.
In such circumstances they must in fact provide on their own the total energy requirements
of the user devices and therefore they tend to be drained rapidly; the higher the
electric power to be delivered, the faster they are drained.
Further, in order to be able to provide better power and
duration performance, these batteries must be sized appropriately, installing a
larger and bulkier group, consequently entailing considerably higher installation
and maintenance costs.
Another disadvantage of conventional apparatuses is that
if the contracted supply limit is exceeded without the electrical mains failing,
the user is not aware of the considerable energy consumption and of the particularly
high costs linked to this consumption; therefore, he is unlikely to reduce his electric
The aim of the present invention is to eliminate the above-mentioned
drawbacks of the background art, by providing a power supply apparatus for electrical
and/or electronic user devices which allows to utilize in a particularly practical
and intelligent manner the energy sources available to supply the user devices,
allowing to reach particularly high delivered power levels for longer periods of
time than traditional types of apparatus and at the same time entailing a reduction
of the costs linked to electric power consumption.
Within this aim, an object of the present invention is
to provide an apparatus which is simple, relatively easy to provide in practice,
safe in use, effective in operation, and has a relatively low cost.
This aim and this and other objects that will become better
apparent hereinafter are achieved by the present power supply apparatus for electrical
and/or electronic user devices, which comprises an uninterruptible power supply
which can be connected electrically to at least one primary power source, to at
least one secondary power source, and to at least one electrical and/or electronic
user device to which the electric power originated from at least one of said power
sources is to be delivered, characterized in that said uninterruptible power supply
comprises at least one electric current management unit which is suitable to connect
electrically said primary power source to said user device in order to deliver electric
power up to a preset threshold value and to activate/deactivate the electrical connection
of said secondary power source to said user device in order to deliver the remaining
electric power absorbed by said user device.
Further characteristics and advantages of the present invention
will become better apparent from the following detailed description of a preferred
but not exclusive embodiment of a power supply apparatus for electrical and/or electronic
user devices, illustrated by way of non-limiting example in the accompanying drawings,
- Figure 1 is a schematic view of a first step of the operation of the apparatus
according to the invention;
- Figure 2 is a schematic view of a second step of the operation of the apparatus
according to the invention;
- Figure 3 is a schematic view of a third step of the operation of the apparatus
according to the invention.
With reference to the figures, the reference numeral 1
generally designates a power supply apparatus for electrical and/or electronic user
devices, which comprises an uninterruptible power supply 2 which can be coupled
selectively, electrically to a primary power source 3, to a secondary power source
4, and to an electrical and/or electronic user device 5, to which the electric power
generated by the power sources 3 and 4 is to be delivered.
Conveniently, the primary power source 3 is constituted
by the ordinary electrical mains, which is nationwide and distributes power to homes,
offices, industries, etc; the secondary power source 4 is instead formed by one
or more rechargeable batteries, which are suitable to accumulate energy to be delivered
As an alternative to batteries, the secondary power source
4 can be constituted by an electric generator, which comprises for example a diesel
engine connected to an alternator or a solar panel suitable to generate electric
power by photovoltaic effect.
According to the invention, the uninterruptible power supply
2 comprises an electric current management unit, not shown in detail in the figures,
which is suitable to connect electrically the primary power source 3 to the user
device 5 in order to allow to deliver electric power up to a preset threshold value
T and to activate/deactivate the electrical connection of the secondary power source
4 to the user device 5 in order to deliver the remaining electric power absorbed
by said user device.
Advantageously, the threshold value T is substantially
lower than the contracted limit of maximum power which can be delivered by the electric
power provider, established by the supply contracts as a function of the type of
user devices to be supplied.
As is known, for example, the ENEL supply can guarantee
to homes 3.2 kW of maximum deliverable power, and therefore the threshold value
provided by the present invention may, preferably, be equal to 3 kW; of course,
if the supplies from the electric mains are different, i.e., allow to absorb a higher
or lower amount of electric power than the 3.2 kW guaranteed to homes, the threshold
value can be different, while remaining lower than the contracted power limit.
The electrical current management unit provided by the
uninterruptible power supply 2 is equipped with a microprocessor, which is connected
to means for detecting the total electric power absorbed by the user device 5, such
as a wattmeter or other suitable apparatus, which allow to monitor the energy demand
of said user device in order to compare it with the threshold value.
If the electric power absorbed by the user device 5 is
higher than the threshold value, the electric current management unit can activate
the delivery of power by the secondary power source 4; if instead the absorbed electric
power is lower than the threshold value, the batteries 4 can be disconnected from
the user device 5, its energy demand being met completely by the primary power source
Conveniently, the electric current management unit is further
provided with electric connection means for electrical connection of the electrical
mains 3 to the batteries 4, such as electric or electronic switching apparatuses,
which are suitable to allow delivery of electric power on the part of the primary
power source 3 in order to recharge said batteries, the sum of the electric power
delivered to the user device 5 and of the electric power delivered to the batteries
4 being lower than, or at the most equal to, the threshold value.
In practice, when the batteries 4 are not required to supply
the user device 5, they can be recharged by utilizing the primary power source 3,
in any case in such a manner that the overall electric power delivered thereby does
not exceed the preset threshold value.
The operation of the device 1 is shown schematically in
the figures: in greater detail, Figure 1 shows the present invention during an operating
step in which the power required by the user device 5 is lower than the threshold
value T and is supplied in full by the primary power source 3.
When the threshold value T is exceeded (Figure 2), the
uninterruptible power supply 2 allows to compensate for the higher energy demand
by causing the intervention of the secondary power source 4 and limiting to the
threshold value the electric power delivered by the primary source 3, so as to never
exceed the contracted limit of maximum power deliverable by the ordinary electrical
Finally, Figure 3 illustrates a step of operation in which
the user device 5, after being supplied by both power sources 3 and 4, again requires
a supply power which is lower than the threshold value; in these circumstances,
the primary power source 3 is used to deliver an amount of power equal to the threshold
value, part of which is intended to supply the user device 5 and part of which is
intended to recharge the batteries 4.
In practice it has been found that the described invention
achieves the proposed aim and obj ect, and in particular the fact is stressed that
it allows to manage intelligently the energy sources from which the power required
to supply user devices is to be drawn.
In particular, the present invention is capable of managing
a primary source from which electric power is to be drawn and one or more secondary
sources, which can intervene to assist the primary one in case of a sudden request
for additional power by the load.
In practice, this allows to utilize fully the ordinary
electrical power supply mains even if the contracted limit that sets its maximum
deliverable power is particularly restrictive.
Moreover, one must not forget that the present invention
allows a considerable economic saving for the user, since it prevents the energy
withdrawal from the electrical mains from being such as to cause the introduction
of the high rates linked to rising above the contracted supply limit.
Further, the present invention allows better utilization
of the batteries, which accordingly can ensure a maximum-power and duration performance
which is distinctly higher than that of traditional apparatuses of equal size.
The invention thus conceived is susceptible of numerous
modifications and variations, all of which are within the scope of the appended
All the details may further be replaced with other technically
In practice, the materials used, as well as the contingent
shapes and dimensions, may be any according to requirements without thereby abandoning
the scope of the protection of the appended claims.
The disclosures in Italian Patent Application No. MO2004A000325
from which this application claims priority are incorporated herein by reference.
Where technical features mentioned in any claim are followed
by reference signs, those reference signs have been included for the sole purpose
of increasing the intelligibility of the claims and accordingly, such reference
signs do not have any limiting effect on the interpretation of each element identified
by way of example by such reference signs.