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Pontifical Catholic University of Rio Grande do Sul - PUCRS
INTEGRATED SYSTEM FOR INTELLIGENT
STREET LIGHTING
G. B. Maizonave, R. Tonkoski Jr., A. Bombardieri, G. B. Ceccon, R.R.N. Souza,
R. W. Dos Reis, J. C. M. Lima and F. S. Dos Reis
Abstract – This work reports the study and hardware implementation of
a dimmable electronic ballast for high pressure sodium lamps, and a
microprocessor-based system for control and energy measurement for this
ballast, which uses a power line communications system to send and receive
status and commands from another ballasts plugged in the same mains
subcircuit. These ballasts are connected in the topology of a logic network, one
of them being defined as the master of the subcircuit, and the others as slaves.
The master unit distinguishes from the slaves by the additional communications
system, which works through a cell phone, and enables the wireless connection
to a PC-based central supervisory system. This way, any locale or town
becomes able to control its entire main lighting system, in addiction to the
obtainment of more accurate data about energy billing, which together with the
ability to control luminosity and the better power factor, will result in financial
and energetic economy.
The SMS Control
Strategy
Tasks accomplilshed by the microcontroller
THE SUPERVISORY SYSTEM
THE ADOPTED INVERTER TOPOLOGY
The power stage of the circuitry is accomplished by one full bridge
inverter and a filter of the type series LC, parallel C. This kind of resonant filter
allows to limit the current through the lamp by the series capacitor Cs and the L
inductor, at the same time performing the lamp ignition, with the high voltage
developed at the Cp capacitor terminals, which is connected in parallel with the
lamp.
Input Voltage and Current
The purpose of this mobile telephony system is to develop a supervisory
system capable of controlling all the street lighting system of a city. Toward this
end, it is necessary to structure the central connection to the master ballasts,
and by this means, command the slave ballasts. The figure illustrates the
supervisory software developed to coordinate the whole system.
Full bridge ressonant inverter
THE POWER METER
Block diagram of the performed operations
Interface of the supervisory system
The power meter circuit is used to measure the power absorbed by the THE DIGITAL CONTROL
CENTRAL
lighting device and to protect the circuit, allowing it to turn off in case of
overload. The calculation of the instant power in a circuit is made by the product
The
next
illustration
of instant voltage and current.
displays, as a block diagram,
the way by which the
electronic ballast’s design is
structured, and how the
control unit integrates this
system. The slave units have
similar construction, lacking
only the connection to the cell
phone.
THE POWER LINE COMMUNICATIONS SYSTEM
Block diagram of the electronic ballast
(master unit)
CONCLUSION
In order to accomplish the communication of the various ballasts with
the sub-central, the mains power line was used as physical media for data
transmission, hence eliminating the need of an additional physical network. The
development of a PLC (Power Line Carrier) was achieved, using only basic
components, as passive elements and logical ports. Communication is
established by modulation, transmission and demodulation of the concerning
data.
The present paper suggests a very attractive design of electronic
ballast for 250 W high pressure sodium lamps. In addition to the
achieved high power factor (0.98 at nominal power), the proposed
model is based on an extremely simple topology, in which the main
concern was providing low cost. A huge communications network
was developed in order to allow total control of the system from the
supervision central. Using this central it is possible to individually
control every street lighting network unit, determinate the timetable of
its activations, deactivations and consumption control, as well as
measuring and recording the individual and the complete system’s
energy consumption.
The developed data reception circuit
The developed data transmission circuit
A conventional SMPS power line filter with differential and
common mode mitigation paths was used. The EMI Filter
topology used is presented below. Usually a capacitor
between the line and the filter is used, in this project the
input capacitor was suppressed once it will block the PLC
communications between the other units.
The
experimental results are presented for the FB topology,
since for the half bridge topology the results obtained are
similar.
Sent (above) and decoded
(below) signals
EMI Filter Topology.
Implemented ballast prototype