Pulse operation of HPS lamp in high-frequency modulation

This paper presents a control technique which permits supplying HPS lamps without using inductive, capacitive or resistive elements; the current through the lamp is established by the resistance of the plasma present inside the discharge tube. The lamp was supplied in a pulsating manner at high-frequency by means of peak current control in order to stabilize the plasma´s temperature and, consequently, its conductivity. The pulses modulated at low-frequency provide improved color rendering index and correlated color temperature for the light emitted by standard HPS lamps. The current stabilization technique was implemented using the full-bridge converter and experimental results demonstrate this technique