Low-frequency Square-wave Sources Research Articles

Single‐stage high‐power‐factor low‐frequency square‐wave‐driven high‐intensity‐discharge lamp ballast

This study presents a single-stage electronic ballast for the high-intensity-discharge (HID) lamp with high-power factor. The presented ballast consists of a discontinuous-conduction-mode operated dual-boost converter to achieve input current shaping, and a high-frequency combined with a low-frequency square-wave-driven half-bridge-type inverter for supplying the HID lamp with low-frequency square-wave sources. The attractive features of the proposed ballast are high-power factor (> 0.99), low total harmonic distortion of input utility-line current (< 10%), high efficiency (> 90%), cost-effectiveness and freedom from acoustic resonance. The operational principles, design guidelines and a design example are included in this paper. A prototype ballast circuit has been successfully implemented and tested for supplying three different brands of 70W HID lamps operating with 110 V-root-mean-square input utility-line voltage. Satisfactory experimental results demonstrate the functionalities of the proposed ballast.

A novel low-frequency square-wave-driven electronic ballast for automotive HID lamps

This paper proposes a novel two-stage electronic ballast used to supply automotive high-intensity-discharge (HID) lamps with low-frequency square-wave sources. The ballast is composed of a flyback converter with two output windings plus cascaded voltage doublers to boost the 12 V input voltage up to a high DC voltage level of 400 V, and a high-frequency combined with low-frequency square-wave-driven half-bridge inverter for supplying low-frequency square-wave sources to the lamp without incurring acoustic resonance. Analysis and design guidelines are included for the presented ballast, as are experimental results of a prototype ballast that features limited-output lamp-power control for providing one 35 W automotive HID lamp with a 12 V input DC voltage.