Naoki Onishi

Single-stage power-factor-correction electronic ballast with a wide continuous dimming control for fluorescent lamps

In addition to their numerous benefits over magnetic ballasts, electronic ballasts can provide dimming capability. However, there are great difficulties in dimming a fluorescent lamp below 40%. One of the symptoms is that the lamp current becomes unstable, or even extinguishes, at a low luminance level. This is due to the interaction of lamps with the ballast. This paper proposes a new family of ZVS-QSW constant-frequency PWM controlled resonant power converters suitable for wide dimming range control. A single-stage power-factor-correction electronic ballast called ZVS-QSW BIBDAC is implemented and tested. It achieves a wide continuous dimming range control, of which a below 1 percent of full light output with stable light output can be achieved. It features high power factor with low total harmonic distortion, low lamp current crest factor, low bus voltage stress, high efficiency and low cost.

Self-oscillating electronic ballast with dimming control

Self-oscillating electronic ballast is one of the simplest and most cost effective ballasts for driving fluorescent lamps. Disadvantageously, however, the operating frequency of the self-oscillating resonant circuit is, by the nature of its operation, load dependent, and thus is very difficult to control. This paper explores a novel, self-oscillating, dimmable electronic ballast ideal for low cost dimming application. The operating frequency can be easily adjusted to regulate the lamp power and dim the lamp. A prototype is implemented and the operation principle is verified by the experimental results.

A fluorescent lamp model for high frequency wide range dimming electronic ballast simulation

A fluorescent lamp model for high frequency dimming electronic ballast simulation is presented in this paper. The model can be utilized for an electronic ballast simulation with continuous dimming and transient mode simulation such as step dimming. The model is implemented using SPICE and verified with experimental results, resulting in good agreement down to 1% dimming level.

High power density electronic ballast for HID lamps

A high power density electronic ballast circuit for high intensity discharge (HID) lamp is proposed. Approaches to achieve high power density are studied. Topologically, the zero-voltage-switching quasi-square-wave concept is adopted when developing the high frequency high efficiency DC/DC front-end converter for the ballast based on the semiconductor loss analysis. On the other hand, a PCB level packaging method is proposed to deal with the thermal related issues, which further improves the power density of the system. A prototype is developed, with a maximum efficiency of 93.3% and the power density of 38.7 W/inch/sup 3/.

A comparative study of a family of charge pump power factor correction electronic ballasts

The charge pump power factor correction (CPPFC) electronic ballast circuit has become an attractive topological family for ballasting fluorescent lamps because it employs a charging capacitor instead of bulky inductor to implement the power factor correction (PFC). Several topologies have been previously proposed. Based on the different mechanism to achieve PFC, three types, namely, voltage source type CPPFC (VS-CPPFC), current source type CPPFC (CS-CPPFC), and combined voltage source and current source type CPPFC (VSCS-CPPFC) electronic ballast can be classified. These three types of CPPFC electronic ballast have different electrical characteristics, such as different start-up bus voltages, etc. Mathematical analysis is given in this paper based on the study of six typical CPPFC electronic ballast circuits. Then a comparison among these circuits in terms of power factor, DC bus voltage stress at preheat, start-up, and steady state modes, current stress at steady state, and lamp current crest factor is presented. The experimental results are provided for verification.

A self-oscillating drive for single-stage charge-pump power-factor-correction electronic ballast with frequency modulation

Single-stage current-source charge-pump power-factor-correction (SS CS-CPPFC) electronic ballast employs charge-pump concept to obtain high power factor with low cost. However, the circuit has a poor lamp current crest factor and large lamp output power variation, which deteriorates the lamp life. Feedforward and/or feedback circuit are usually used to deal with these problems at the penalty of adding circuit complexity and cost. This paper introduces a novel self-oscillating drive circuit with a switch frequency modulation that avoids complicated control circuit. Self-oscillating principle and general structure are discussed. Current drive source selection and current injection concepts are originally developed to achieve constant lamp power operation and low-crest factor. It is shown that with this simple, low cost, passive drive system, total harmonic distortion, low current stress, low-crest factor, and constant lamp power operation are achieved.

Self-oscillating single-stage power-factor-correction electronic ballast with duty-ratio and frequency modulation

This paper presents the analysis and design of self-oscillating single-stage power-factor-correction electronic ballast with duty-ratio and frequency modulation. The proposed ballast integrates a boost converter with a self-oscillating half-bridge inverter. A near unity power factor as well as low bus voltage, low lamp current crest factor, and constant lamp power is achieved by the proposed novel duty-ratio and frequency modulation scheme. Experimental results are provided for verification.

New charge pump power factor correction electronic ballast with a wide range of line input voltage

A new charge pump power factor correction (CPPFC) electronic ballast with a wide line input voltage range is proposed in this paper. Circuit derivation and DC bus voltage stress at start-up mode are discussed. The average lamp current control with switching frequency modulation is developed to achieve constant lamp power operation and low crest factor. The proposed CPPFC electronic ballast is analyzed, implemented and evaluated. It features continuous line input current, low THD, constant lamp power operation, low crest factor and less switching current stress with low DC bus voltage stress for line voltages from 180 V to 265 V.

Optimization of combined voltage-source-current-source charge-pump power-factor-correction electronic ballast

The charge-pump power-factor-correction (CPPFC) electronic ballast has become attractive for ballasting fluorescent lamps because it employs a charging capacitor instead of a bulky inductor to achieve the power-factor-correction. Several topologies have been previously proposed. Among them, the combined voltage-source-current-source (VSCS) CPPFC electronic ballast with improved-crest-factor (ICF) has a better overall performance. However, the operation principle is not straightforward, making the subsequent design difficult. In this paper, circuit derivation and mathematical analysis are first presented, then a design guideline is proposed, and finally, electronic ballast with two 45-watt fluorescent lamps is implemented optimally as an example of this topology.