Note: Descriptions are shown in the official language in which they were submitted.
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HIGH EFFICIENCY LIGHTING SYSTEM
BACKGROUND OF THE INVENTION
The field of the invention is low voltage, direct
current (DC), high efficiency, uninterruptible lighting and
DC power systems capable of operating simultaneously with a
multiplicity of alternating current (AC) and DC power
sources.
Uninterruptible power supplies are known accessories
especially when applied to computer equipment to "ride out"
brief line power outages so that no data is lost or
compromised and in emergency lighting systems where lighting
integrity is essential. Many have limited battery storage
capability due to ordinary high battery storage volume
requirements and high storage battery unit cost. Therefore,
operation periods with conventional uninterruptible means may
not be maintained for an extended outage. Some special
lighting systems are also protected in a similar fashion by
an alternating AC power source for critical applications such
as operating rooms in hospitals. Such systems, whether using
storage batteries or AC auxiliary power sources tend to be
complex and relatively expensive, and as a result are limited
to only the most valuable applications. With consideration
for cost many of these system are also compromised in output
performance and durability. In lieu of such considerations,
reduced amounts of auxiliary emergency lighting or other
power needs are provided for only special applications and
are served by packaged "add-on" systems which are only
applied and engaged during power outages and not for normal
3o standard lighting needs; these kinds of packages are often
used in stairwells and consist of a simple housing enclosing
a battery, basic charger, a power sensor means and one or two
simple flood lamps of limited light output capacity.
These prior art systems, even if more complex and
elaborate in construction, are compromised in performance,
due to cost, and do nothing to enhance lighting quality,
efficiency, or in other ways enhance the value of the power
application except through its limited uninterruptible
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operation during critical power outages, and would not be
considered as equivalent or economical substitutes for
conventional lighting or other end-uses.
FEATURES OF THE INVENTION
It is a feature of this invention to provide, in one
embodiment, an uniterruptible lighting system and/or end-use
power system that can be more versatile and that can be
routinely substituted for conventional building or office
lighting and other end-uses as if it were intended for
conventional end-use needs without compromised end-use
performance.
It is another feature of preferred embodiments of this
invention to provide high efficiency operation with lower
operating cost than conventional incandescent and fluorescent
lighting systems.
It is yet another feature of a preferred embodiment of
this invention to provide longer term uninterruptibility (3
hours +) with small storage volumes.
It is a feature of preferred embodiments of this
invention to provide optimum battery management for longer
stationary battery storage life, lower maintenance, and more
economical operation.
It is a further feature of a preferred embodiment of
this invention to provide for compatible and economical
connection to alternate energy sources such as solar
photovoltaic (PV) panels, fuel cells and other similar DC
power supply devices and to manage these sources in relation
to serving the output load or loads while maintaining the
storage battery within its preferred performance range.
It is another feature of preferred embodiments of this
invention to provide a system with enhanced safety through
low voltage operation nominally at 26.6 volts for a two lead-
acid, 12 volt battery system at room temperature between the
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power control unit and the lighting fixtures or other DC end-
use devices. Other battery systems may also be applied and
the output service voltage so adjusted for optimum battery
maintenance and life, while serving a suitable DC compatible
load.
It is yet another preferred feature to achieve high
power quality through dynamic high power factor correction
and similarly achieving low total harmonic AC supply line
distortion.
It is a feature of preferred embodiments of this
invention to achieve greater overall application value and
service quality with low voltage operation while still using
standard building wiring and wire sizes while achieving very
small voltage drops.
It is still another feature of preferred embodiments of
this invention to provide overall building power integrity
for lighting and other end-uses that are immune to area and
central disruptions such as bombings and confined disasters
through a modular independent power in-line device between
the AC circuit breaker and the end-use that increases system
and subsystem integrity with simple component
standardization.
It is yet another feature of a preferred embodiment of
the invention to provide a universal power interface that
accepts a multiplicity of both AC and DC electric power
sources simultaneously and directs them to the lighting
and/or end-use application in a shared manner.
It is still another preferred embodiment of the
invention to provide a universal power interface that accepts
a multiplicity of AC or DC electric power sources singularly
and without the other in support of the lighting and/or end-
use application with conventional end-use expected quality.
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It is still a further feature of a preferred embodiment
of the invention to provide a method and a means to utilize
the invention as a power interface where low voltage, DC
operation may be utilized in buildings where there is
conventional standard high voltage AC wiring and cable sizes.
It remains still a feature of the invention to provide,
in preferred embodiments, a modular structure which allows
the power units to be connected in series to satisfy higher
DC operating voltages in increments of the individual power
unit design voltage.
SUMMARY OF THE INVENTION
In accordance with one embodiment of the present
invention there is provided a power system applied to
lighting and other end-use applications system for
maintaining normal lighting conditions with conventional
lighting fixtures and other end-use electrical power
applications requiring DC electrical power, the power system
comprising: power control means for receiving AC alternating
current electrical power of many frequencies from a source
and alternatively DC power from a source, and for delivering
required regulated low voltage DC electrical power to voltage
matched lamp or lamps within the lighting fixtures or at
least one DC compatible end-use device load; the power
control means converting the AC electrical power to DC
voltage regulated electrical power; the power control means
combining the converted AC to voltage regulated DC with the
alternative DC power source in service to the at least one DC
compatible load; the power control means altering the
converted DC output voltage as a means of controlling power
delivered by the alternative DC power source; the power
control means supporting electrical load or loads with or
without an alternative DC power source in service to the at
least one DC compatible load; and the power control making
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a shared contribution of power from the AC power source which
has been converted to DC power and the alternative source of
DC power and having a voltage regulated power junction means
for delivering the low voltage DC electrical power to the
lighting fixtures or other end-use electrical power
application.
In another embodiment of the present invention there is
provided a power control for use in a high efficiency
lighting system for maintaining normal lighting conditions by
lighting fixtures requiring DC electrical power comprising:
an AC connection for receiving AC electrical power from a
grid source and an output connection for delivering required
DC electrical power to the lighting fixtures; a converter
converting the AC electrical power to DC electrical power;
a connection for a battery for providing on a standby basis
the required DC low voltage electrical power to the power
control means; the battery connection being connected to the
converter for maintaining a connected battery in a fully
charged condition when AC power is connected to the AC
connection during normal supply of AC electrical power from
the grid source; the power control delivering the required DC
electrical power from the battery means to the lighting
fixtures during an AC electrical power outage to maintain
without interruption normal lighting by the lighting
fixtures; and the power control making a shared contribution
of power from the AC power source which has been converted to
DC power and the battery and having a voltage regulated power
junction means for delivering the low voltage DC electrical
power to the lighting fixtures.
Yet another embodiment of the present invention provides
a power sharing system comprising: a primary source of AC;
an alternative primary source of DC; a secondary source of
DC; a power controller capable of inputting power
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simultaneously from the primary sources, the alternative
primary source of DC making a shared contribution of power
selected by the power controller, and having a power junction
means for delivering a constant voltage DC to at least one DC
compatible load at an output of the power sharing system; the
power controller having a converter converting inputted
electrical power into a defined DC-regulated voltage to
provide and manage power to the DC compatible load; the
secondary source of DC being a battery to supply power in the
event of a failure in a primary source of power, the power
controller maintaining the battery in a fully charged
condition; and the power controller biasing the power
function means for drawing power from the secondary source of
DC power to limit peak power supplied from the primary source
of AC power to the at least one DC compatible load in
accordance with a pre-set threshold of power from the primary
source of AC power in order to reduce peak power surcharges.
A still further embodiment of the present invention
provides a method for controlling electrical power by a power
control for use in a high efficiency lighting system for
maintaining normal lighting conditions by lighting fixtures
requiring DC electrical power comprising the steps of:
providing an AC connection for receiving AC electrical power
from a grid source and an output connection for delivering
required DC electrical power to the lighting fixtures;
converting the AC electrical power to DC electrical power in
a converter; providing a connection for a battery for
providing on a standby basis the required DC low voltage
electrical power to the power control means; connecting the
battery connection to the converter for maintaining a
connected battery in a fully charged condition when AC power
is connected to the AC connection during normal supply of AC
electrical power from the grid source; the power control
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delivering the required DC electrical power from the battery
means to the lighting fixtures during an AC electrical power
outage to maintain without interruption normal lighting by
the lighting fixtures; and the power control also making a
shared contribution of power from the AC power source which
has been converted to the DC power and the battery and having
a voltage required power junction means for delivering the
low voltage DC electrical power to the lighting fixtures.
In accordance with another embodiment of the present
invention there is provided a power control for use in a DC
load system requiring DC electrical power, comprising: an AC
connection for receiving AC electrical power from a grid
source and an output connection for delivering required DC
electrical power to the DC load; a converter converting the
AC electrical power to DC electrical power; a connection for
a battery for providing on a standby basis the required DC
low voltage electrical power to the power control means;
the battery connection being connected to the converter for
maintaining a connected battery in a fully charged condition
when AC power is connected to the AC connection during normal
supply of AC electrical power from the grid source; the power
control delivering the required DC electrical power from the
battery means to the DC load during an AC electrical power
outage to maintain without interruption normal lighting by
the lighting fixtures; and the power control also making a
shared contribution of power from the AC power source which
has been converted to DC electrical power and the battery and
having a voltage regulated power junction means for
delivering the low voltage DC electrical power to the DC
load.
The present invention includes an application of a high
efficiency lighting system for maintaining normal lighting
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levels and conditions by using normal lighting fixtures
incorporating a variety of DC electronic ballasts for use
with gas discharge lamps requiring DC electrical power as
defined by the voltage requirements of this current
invention.
20
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The system includes a power control means for receiving
AC and/or DC electrical power from a source and delivering
the required low voltage DC electrical power to the lighting
fixtures or DC compatible end-use. When connected to an AC
power source the power control means converts the source of
AC electrical power into a regulated low voltage DC
compatible with the long-term "float" voltage requirements of
a stationary rechargeable storage battery electrical system.
A battery provides, on a standby basis, the required DC
low voltage electrical power to the power control means. The
storage battery as in the example of a lead-acid design is
connected to the power control means so that the battery may
be maintained in a fully charged and "float" condition by the
power control means during normal supply of AC electrical
power from the grid or similar AC source .
The power control means also serves to deliver the
required DC electrical power from the battery to the DC
compatible lighting fixtures or compatible end-use during an
AC electrical power outage to maintain the DC operating power
without interruption.
The power control means can be a plurality of multiple
power control means, each connected to its own battery and/or
alternative DC power source for maintaining the lighting or
end-use power in a building with multiple rooms and area
requirements
An optional photovoltaic (PV) source of DC electrical
power may be connected to the power control means for
proportionally reducing the amount of electrical power taken
from said grid or similar AC source. The control means
further is capable of directing any excess PV power, not
required by the electrical load to an optionally connected
storage battery without exceeding it's safe and stable long-
term operating requirements. If the power application does
not include the battery the control means will similarly and
proportionally support the load with the AC source while not
exceeding operational limits.
The storage battery provides, on a standby basis, DC low
voltage electrical power to the load, in the event that the
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control means highly regulated DC voltage drops below the
battery voltage, as in the case where the AC source
interrupts the converted DC supply from the control means.
Otherwise the power control means maintains the battery in a
5 fully charged and standby "float" condition by electrical
power from an AC grid source.
In one version of this invention, AC power input is
converted by the power control means into the same regulated
DC "float" voltage, without the use of a battery or axially
DC source, thus satisfying a low voltage DC lighting. High
efficiency gas discharge lighting is thus achieved by optimum
voltage control and very high AC to DC conversion
efficiencies provided by the power control means, with its
switching-mode voltage regulator design, and further by the
elimination of similar AC to DC conversion components in the
DC ballasts, as in conventional electronic ballasts designs.
While switching-mode voltage regulation is preferred, in this
invention the invention is not limited by such voltage
regulation means.
The power control means may also include circuitry to
prevent DC current from exceeding a predetermined limit,
while still delivering power. The power control means may
also include other circuitry to detect a short circuit such
that the power control means can interrupt DC power delivery
until the short circuit is removed.
This system for maintaining normal power for lighting
fixtures requiring DC electrical power, includes the power
control means for receiving DC electrical power from a DC
source and delivering required DC electrical power to the
lighting fixtures, as well as a power control means
converting AC electrical power to DC electrical power.
In a further embodiment for remote use, such as a remote
facilities without access to conventional AC power, a high
efficiency lighting system maintains normal lighting
conditions with lighting fixtures requiring DC electrical
power. The remote system includes a power control means for
receiving DC electrical power from a suitable auxiliary DC
power source such as a photovoltaic panel and delivering
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required low voltage DC electrical power to the remote
facility lighting fixtures and/or compatible end-use
application, and a storage battery. The power control means
also serves to control charging of a battery to a maximum and
optimum state-of-charge.
The battery also provides, on a standby basis, the
required DC low voltage electrical power to the power control
means. It is connected to the power control means while
being maintained in a charged condition by the power control
means, during availability of the DC power source as in the
case of sunshine hours of input of power from the
photovoltaic panel.
Moreover, the power control means delivers required DC
electrical power from the battery to the lighting fixtures
during periods of time when power from the auxiliary DC
source or photovoltaic panel is not available, such as when
the source must be interrupted for specific reasons as at
night and cloud cover times for the PV source.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention can best be understood in
conjunction with the accompanying drawings, in which:
Figure 1 is a block diagram of basic power system
applied to lighting showing the basic input and output power
connections;
Figure 2 is a physical block diagram of basic power
system used as an uninterruptible lighting system with the
battery system connected but without an auxiliary DC power
input, such as photovoltaic (PV).
Figure 3 is a wiring layout of a single lighting circuit
configuration using a concept called a cluster that avoids
excessive low voltage current carrying cable lengths and
voltage drops from the low voltage DC power module;
Figure 4 is a wiring layout of a four power module
system accommodating a larger lighting area requirement that
avoids excessive low voltage operational cable lengths and
voltage drops while supported from a single AC high voltage
line and circuit breaker;
Figure 5 is a block diagram of lighting system as in
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Figure 2 but with a PV panel;
Figure 6 is a front view of power control unit with
typical power input and output power connections;
Figure 7 is a wiring diagram and specifications for a
two lamp low voltage DC gas discharge ballast having
compatibility with the power control unit;
Figure 8 is a wiring diagram and specifications for a
single lamp low voltage DC gas discharge ballast having
compatibility with the power control unit;
Figure 9 is a front view of battery containment
enclosure;
Figure 10 is a block diagram of a power control unit
showing typical power input and output power connections and
the internal functions of the power control unit; and,
Figure 11 is a block diagram of an alternate energy
option lighting system using natural gas cogeneration as an
alternative DC power source.
DETAILED DESCRIPTION OF THE INVENTION
Figure 1 shows a block diagram of the major components
of an uninterruptible lighting system supported by this
invention. This system may also be used for other DC
compatible loads that are designed to use the output voltage
of the power invention. It may be installed anywhere
conventional building lighting or other end-use devices are
required. Unlike emergency lighting and other emergency power
systems, this is a full service, high quality end-use power
product. It functions with standard fixtures, lamps and DC
compatible devices, without compromise in output performance
in the event of an conventional power failure. This permits
3o normal power supporting functions to continue for extended
hours using battery storage without disruption of work
activity due to loss of lighting and potentially other power
needs. The key subsystem that ties the entire system
together is the power control unit (PCU) 1 which normally
uses standard AC grid power to support the end-use
application and keep the optional storage battery 2 in an
optimal state of charge. When used to support lighting the
lighting fixtures 3 are gas discharge lamps like fluorescent
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tubes using electronic ballasts which require a low voltage
(nominal 26.6 volts) DC input supplied by line 5 from power
control unit 1. Other lamp types may also be used, such as
incandescent lamps. During a power outage, the DC line 5 is
supplied by battery 2.
Figure 2 shows a physical block diagram showing the AC
electric service panel 6 with a standard three wire cable
system supplying either voltages of 120 through 277 VAC to
PCU 1. Battery case 7 normally contains two group 24/27 size
deep discharge lead-acid storage batteries 8 wired in series
and through a 30 amp fuse 9 and cables 10 and 11 to the PCU
1. The wiring to all lighting fixtures and compatible end-
uses 3 is at a nominal working voltage of 26.6 volts DC. In
the nominal embodiment, each PCU 1 can power ten two tube 48
inch T8 fluorescent fixtures or 20 single tube fixtures 3 or
any equivalent electrical DC load of 25 amps of current at or
near the design maintenance voltage of the storage battery
system used.
Figure 3 shows a wiring layout for a typical office
lighting application 15 with walls 16 as supported by a
single PCU 1. A closet area 17 conveniently serves to house a
relatively small battery volume 2. The AC line 4 leads to PCU
1 which because of its compact size may be advantageously
mounted in the ceiling cavity. The DC wiring 5 to the
lighting fixtures is also in the ceiling cavity and due to
close proximity of the PCU 1 provides a short wiring path to
the lighting fixtures 3. This arrangement of low voltage
connected lighting loads forms an integral cluster that many
be duplicated many times from a single supporting high
3o voltage AC line as shown in Figure 4 while still minimizing
load support voltage drops.
The PCU 1 is electronically input compliant to a wide
range of continuous AC supply voltages and will accommodate a
range of inputs from 110 to 277 VAC in the PCU 1. The input
power to the PCU 1 is a nominal 725 watts for an AC rms
current ranging from 2.6 to 6.6 amps depending on the AC
input voltage. The equivalent range of input AC currents
will vary depending on the AC input voltage. Because the PCU
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1 is highly power factor corrected to .99, a 20 amp circuit
breaker and number 12 wire can be expected to support a large
number of PCUs and their corresponding lighting capacity
achieving a maximum of 3 PCU's from a 120 volt line.
Similarly 6 units may be supported from a 277 volt line for a
total DC power output of about 4000 watts and an AC input of
4300 watts respectively.
Figure 4 shows a wiring layout of office area 19 with
walls 16 serving 8 small offices and four larger ones. This
involves the use of four separate uninterruptible lighting
systems using four PCU's 1 and four battery modules 2 located
in four central closets 17. The four PCU's are supplied from
a single 220 VAC circuit breaker in power panel 6 via AC
cable 4 as distributed from distribution box 20. Each of the
lighting systems supplies 10 two lamp fixtures 3.
There are several different power modes possible with
the PCU 1. Figure 5 shows an uninterruptible lighting system
that includes AC electric service panel 6, battery case 7
with batteries 8 and fuse 9 connected by cables 10,11 to PCU
1, as well as photovoltaic (PV) panel 25. This mode allows
solar energy to be a auxiliary power source to the AC line
while maintaining the storage battery case 7 with batteries 8
as a power supplement during AC outages and solar variations.
As shown in Figure 6, a front view of PCU 1, it is a
simple matter to wire the PV panel to the PCU 1 without
complicated AC power conditioners as in convention PV
applications. The PV panel is merely connected to two PV
input terminals on the PCU 1. This mode permits high
reliability lighting using an AC line, battery back-up, and
PV as overlaying power sources.
The simplest power operating mode is when the AC is the
only input power source with the PCU 1 supporting a low
voltage DC lighting system. Such a system with the PCU 1
alone attached to the AC line is a viable high efficiency
lighting system with minimum interface power losses that can
pay for itself by reducing energy consumption. By simply
connecting the battery subsystem to the basic system above,
the user achieves the additional power mode satisfying
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uninterruptible DC power operation in support of lighting.
Still another power mode of operation is achieved by using
the PCU 1 without a battery but with AC input and a PV panel.
In this mode the PV contribution is preferentially absorbed
5 by the DC load with the balance supplied by the AC input.
In still another power operating mode where the PCU 1
may be used as a stand alone power system without grid
supported central AC generation. Such a system is desirable
in an area remote from the AC grid. With such a system, using
10 the PCU 1 attached to a suitable PV panel and a suitable
rechargeable storage battery, solar lighting and other DC
load needs may be satisfied including an DC to AC 60 HZ power
inverter.
The PCU 1 is distinguished by being sufficiently
flexible to support a multiplicity of power operating modes
while satisfying lighting and other electrical requirements.
It can also supply other DC loads such as household
appliances, microwave ovens, DC refrigeration and the like.
Furthermore, it can also alternately accept external DC power
from many varied sources other than photovoltaic (PV), such
as wind generators or a engine powered DC generator.
Figure 6 also shows a front view of PCU 1 with finned
heat sink 28 and terminal strip 29.
Figures 7 and 8 show the wiring diagrams and
specifications for the two lamp and one lamp DC ballasts
respectively.
Figure 9 shows a front view of the battery case 7 with
housing 35, hinged lid 36 and latches 37. It is a
thermoplastic case rated for sealed type lead-acid batteries.
Figure 10 shows a block diagram of the PCU 1. The AC
input is rectified by DC Rectifier Means such as a bridge
circuit. The Power Factor Correction Means is used to
achieve a high power factor and low total harmonic distortion
at the AC input. The Control Means and Voltage Regulator
means interact through circuits such as pulse width
modulation and DC to DC switching power supply topologies to
provide the nominal 26.6 volts to the lighting ballasts or
other suitable DC loads through the power junction means.
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Figure 10 also shows the Control Means and Voltage Regulator
means may further interact to limit the upper operating
current of PCU 1 and further to shut down the DC output of
the PCU 1 in the event of a detected short circuit. Such
short circuit detection circuitry being continually active
and dynamic and thus resetable at any time to normal. Other
voltages including programmable voltages are also possible,
such as 13.3, 26.6, 39.9 etc. to support higher series
connected battery system and control requirements.
The Battery Undervoltage Cut-Off disconnects the battery
in situations of charge depletion to prevent over discharging
that contributes to chemical and physical damage to the
storage battery. The PV Voltage Regulator and Suppressor is
a power conditioner/controller to suppress voltage transients
and also to prevent dangerous over charging of the storage
battery from the PV panel.
Figure 11 is an alternate embodiment for a powered
lighting system including natural gas cogeneration. AC power
50 is normally converted to DC power by the PCU 1 consisting
of the DC power converter 51 and control means 52 or
otherwise specified by the operations of PCU 1. However, a
cogenerator in the form of a gas fueled DC generator 53
receives natural gas as an primary energy source from a
natural gas source 54, and converts it into DC power to
support building lighting system 55, such as electronic
ballasted fluorescent lighting. This system can provide a
flatter and more predictable power demand curve for electric
utilities by altering the customers demand using building
the lighting system 55, supplemented by the gas energy source
thus mitigating peak power from electric utility generating
sources. This can result in reduced demand charges.
The cogeneration system can run continuously for
lighting load 55, and does not require costly synchronous 60
HZ power inverters to be sent back through the AC power line
50.
DC gas generator 53 directly couples to building
lighting system 55 through the auxiliary DC input of the PCU
1 to operate building lighting system 55.
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Other embodiments may be applied to the present
invention without departing from the scope of the invention,
as noted in the appended claims.
