Constant-Frequency Magnetically Controlled Universal Ballast With SoS Compliance for TL5 Fluorescent Lamps

Abstract

Abstract-This paper presents the development of a universal electronic ballast for TL5 lamps. The intent is to efficiently operate the maximum number of TL5 lamps with different power ratings at nominal power, using a resonant variable inductance, provided by a magnetic regulator, while maintaining the switching frequency constant. A microcontroller and additional digital circuitry are used to command a dc-dc buck converter to supply the necessary dc control current to the magnetic regulator and to regulate the switching frequency of the half-bridge resonant inverter that supplies the lamp. The selection of the resonant capacitance is done in order to comply with the SoS limits established for each lamp. Experimental results with lamps ranging from 14 to 49 W, operating with high efficiency and high output, are presented in this paper.

Interleaved high step‐up zero‐voltage‐switching boost converter with variable inductor control

“…The structure of the variable inductor that uses a double E core is shown in Fig. 4a [19][20][21][22][23]. The control winding is divided into two identical portions with the number of turns N c and is mounted on the lateral legs of the core.…”

“…Moreover, the output voltage can be regulated by varying the inductance, and high-power density can be achieved by operating the converter at a fixed frequency and duty cycle under a soft switching condition. Variable inductors have been used extensively in power applications in recent years [19][20][21][22][23]. The inductance of variable inductors can be changed by using a DC-bias current that www.ietdl.org circulates through a control winding.…”

Design and analysis of a novel coupled inductor structure with variable coupling coefficient

“…The same idea is applied in Inductor-Inductor-Capacitor resonant converter for battery charging applications [25]. In [26], VI is successfully used for equalisation of branch currents in multi-array lightemitting diode (LED) lamps, as electronic ballasts for fluorescent lamps [27][28][29] and for reducing line-current harmonics in singlestage LED driver [24]. VI has also been employed in voltage regulator module for improving transient response [30], and more recently for core size optimisation in bidirectional DC-DC converters for electric vehicles [31].…”

Automatic lamp detection technique for fluorescent lamps electronic ballasts

“…In [16] a method to detect fluorescent lamps of 18 W, 36 W, and 58 W, based on a variable resonant inductor is shown. An evolution of [16] is presented in [17], which take into account filaments heating in the resonant circuit design. An alternative to implement fluorescent lamp detection is to change duty cycle and/or switching frequency of the half-bridge inverter that supplies the lamp, as shown in [18].…”