Penta-Phase Series-Parallel $LC_{s}{C}_{p}$ Resonant Inverter to Drive 1-kW HPS Lamps

This paper presents the analysis and design of a new configuration of a resonant inverter suitable for high-pressure sodium lamp ballast applications. The proposed inverter is the result of the parallel connection of five class D LCsCp resonant inverters. Since the load current is shared among five equal sections, the circuit is able to drive lamps over 1 kW using low-cost power MOSFETs and achieves better efficiency than single class D solutions due to the reduction of the conduction losses. The regulation is implemented at constant frequency, modifying the phase displacement of the output voltage of one inverter section with respect to the others.