Injection of adjacent frequency signals for acoustic resonance avoidance in HPS lamp

The high pressure sodium (HPS) lamp has widely been used in lighting for its efficacy. However, acoustic resonance is the main problem in lamp supply under high frequency operation. This paper proposes a method for acoustic resonance avoidance via the injections of several signals of adjacent frequencies using a half bridge LCC electronic ballast. The study shows that further signals can be introduced in the circuit in order to reduce the effect of acoustic resonance without modifying control structure or ballast. The full experimental results will be in the full paper.