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AbstractThe prupose of this thesis is to implement the
electronic ballast forhigh pressure sodium (HPS) lamps. High
pressure sodium lamps have luminous efficiencies close to twice
as that of high pressuse mercury vapor lamps. There is, hence,
an increasing tendency to replace existing mercruy lighting
systems with high pressure sodium systems.Traditional systems
used to supply HPS lamps include an electromagnetic ballast and
a starter. However, these systems presenthigh weight and size,
low efficiency and poor lamp power regulation.For these reasons,
in this thesis the new electronic ballast based on solid-state
devices is studied to substitute traditional eletromagnetic
ballasts. The proposed electronic ballast included a high
voltage(about 3.6KV) igniter, controlling circuit with dimming
capability andthe power stage built around a half bridge
inverter. It was used to drive and examine the high frequency
characteristies of a commercial HPS lamp. The results of this
study reveal that commercial HPS can be characterized as pure
resistance whem driven at high frequency.The resistane is
independent of the switching frequency or power levelaccording
to the experimental results. The effects of voltage sags,
interruptions, and fluctuaions on high pressure sodium lamps are
also studied in this thesis for the reason of safety.
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