Single-stage line-coupled half-bridge ballast with unity power factor and ripple-free input current using a coupled inductor

A single-stage line-coupled half-bridge ballast with unity power factor and ripple-free input current using a coupled inductor is proposed. The proposed power-factor-correction circuit can achieve unity power factor and ripple-free input current using a coupled inductor. A saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. The proposed ballast has high energy efficiency, low cost, and high reliability compared to the conventional high-power-factor electronic ballasts. Experimental results obtained on a 30-W fluorescent lamp is discussed.     

Single-stage electronic ballast with high-power factor

This article proposes a single-stage electronic ballast circuit with high-power factor. The proposed circuit was derived by sharing the switches of the power factor correction (PFC) and the half-bridge LCC resonant inverter. This integration of switches forms the proposed single-stage electronic ballast, which provides an almost unity power factor and a ripple-free input current by using a coupled inductor without increasing the voltage stress. In addition, it realises zero-voltage-switching (ZVS) by employing the self-oscillation technique. The saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Therefore, the proposed single-stage ballast has the advantage of high-power factor, high efficiency, low cost and high reliability. Steady-state analysis of the PFC and the half-bridge LCC resonant inverter are described. The results of experiments performed using a 30 W fluorescent lamp are also presented to confirm the performance of the proposed ballast.     

Improving crest factor of electronic ballast-fed fluorescent lampcurrent using pulse frequency modulation

In case where electronic ballast employing a valley-fill passive power-factor correction (PFC) circuit is used for feeding fluorescent tamps, a new method to reduce crest factor of the lamp current is studied in this paper. It is known that a 50% valley-fill passive PFC provided for high input power factor results in undesirable value of crest factor of the fluorescent lamp current, In order to reduce crest factor to a lower value, a pulse frequency modulation technique based on the waveform of the DC-link voltage which is predetermined by the passive PFC circuit is taken into the switching control action of the electronic ballast. An equation-based analysis between the crest factor of lamp current and the effect of varying the inverter switching frequency is comprehensively performed. Several simulation and experiment results illustrate the Effectiveness of the proposed control scheme     

New charge pump power-factor-correction electronic ballast with awide range of line input voltage

A new charge pump power-factor-correction (CPPFC) electronic ballast with a wide range of line input voltage 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 total harmonic distortion (THD), constant lamp power operation, low-crest factor, and less switching current stress with low-DC-bus voltage stress for the line voltages from 180 to 265 V     

A Novel Constant Power Control Circuit for HID Electronic Ballast

This paper presents a constant power control circuit for a three-stage high-intensity discharge (HID) electronic ballast. The three-stage electronic ballast is composed of a boost pre-regulator to achieve a high power factor, a DC/DC buck converter to regulate lamp current with constant lamp power, and a full-bridge inverter to drive the HID lamp with a low-frequency ac squarewave current. The buck converter operating in current mode utilizes current sense level-shift technique to achieve constant power output. The proposed constant power control circuit is easily designed and implemented for the three-stage HID electronic ballast. Finally, a laboratory prototype of a 70 W HID electronic ballast is implemented. The measured results show that the proposed ballast can be applied for various HID lamps with low lamp power variation (less than 0.6%).     

Single-switch electronic ballast with continuous input current charge pump power-factor correction

This paper presents a single-switch electronic ballast with continuous input current charge pump power-factor correction. The ballast circuit is composed of a series/parallel inverter, a charge pump power-factor corrector, and a dimming controller. The characteristics and design considerations of this ballast are discussed in this paper. Dimming control is achieved by varying the switching frequency. The frequency-modulation scheme is used to reduce the low-frequency output current ripple. A prototype of a 36WT8 fluorescent lamp ballast has been implemented and tested. Experimental results verify the analytical derivations.     

An improved charge pump power factor correction electronic ballast

An improved charge pump power factor correction (CPPFC) electronic ballast using the charge pump concept is proposed in this paper. Circuit derivation, principle of operation, and the conditions for achieving unity power factor are discussed. The proposed electronic ballast is implemented and tested with two 40 W fluorescent lamps. It is shown that 84% of overall efficiency and 1.6 of crest factor can be achieved with 200-V line input voltage. The measured line input current harmonics satisfy IEC 1000-3-2 Class C requirements. The lamp power variation range is automatically limited within ±15% for ±10% line input voltage variation without feedback control     

250W高压钠灯电子镇流器的研究

为满足人们对绿色照明的要求,该文设计了节能、高功率因数及总谐波失真低的高压钠灯电子镇流器来替代传统的电感式镇流器,采用有源功率因数校正、恒功率控制、低频方波驱动的三级式结构的电路设计,并搭建了样机,实现了160V～265V宽电压输入,功率因数PF≥0.99,总谐波畸变因数THD≤9．1％,电路可靠工作,通过了电磁兼容传导干扰测试。     

A Modified Valley Fill Electronic Ballast Having a Current Source Resonant Inverter With Improved Line-Current Total Harmonic Distortion (THD), High Power Factor, and Low Lamp Crest Factor

In this paper, a modified valley fill (VF) circuit is employed to combine with a current-fed resonant inverter as a passive high power factor (PF) electronic ballast. A conventional VF circuit limits the line current to conduct when the conduction angles are: 30deg les omegat les 150deg and 210deg les omegat les 330deg during the line period, which results in high total harmonic distortion (THD). The modified VF circuit has the following advantage: When the capacitors are connected in parallel, the voltage across the capacitors is one-third of the peak voltage, which allows the conduction angle of the line current to be further extended to 19.5deg les omegat les 160.5deg and 199.5deg les omegat les 340.5deg, so that a lower THD can be achieved. The high lamp crest factor (CF) problem generated by the high ripple voltage from the modified VF circuit is improved in the proposed ballast as variable frequency control is employed to continuously regulate the lamp current. An experimental prototype is then built in the laboratory to verify the feasibility of the proposed work for a 26-W compact fluorescent lamp. The final results confirm that a PF of 0.986 and a lamp CF of 1.49 are achieved with the proposed circuit, whereas a PF of 0.96 is achieved with the conventional VF ballast.     

Low-cost high power-density electronic ballast for automotive HIDlamp

A low-cost high-efficiency high power-density electronic ballast for 35 W automotive high intensity discharge (HID) is presented along with the results of theoretical computations and experimental tests. The ballast circuits is based on a 100 kHz resonant inverter, a half-wave rectifier and a 400 Hz operated square-wave inverter. The converter operates at zero turn on losses, nearly zero turn off losses, and at a reduced electromagnetic interference level. The ballast circuit is designed to prevent inappropriate operations due to the acoustic resonances. The lamp voltage waveform has limited dv/dt and no DC component contributing to a long operating life of the lamp. A breadboard of the electronic ballast was designed and experimentally tested on a 35 W lamp, for a DC input voltage ranging from 9 V to 16 V. The electronic ballast performs all the features required to turn-on, warm-up and drive at the steady state a 35 W HID lamp and operates at a maximum steady state efficiency η=84%,     

Charge pump power-factor-correction dimming electronic ballast

A voltage-source charge pump power-factor correction (CPPFC) continuous dimming electronic ballast is proposed in this paper. The basic charge pump PFC principle is presented, and its unity power factor condition is then reviewed. Constant lamp power control and crest factor correction technique in dimming mode operation are then discussed. A continuous dimming controller with average lamp current control and duty-cycle modulation is developed so that the lamp is able to operate in constant power and low crest factor from 20% to 100% dimming level. The developed dimming electronic ballast has features of higher than 0.99 power factor, low crest factor, and low-DC-bus voltage     

High frequency electronic ballast provides line frequency lampcurrent

Most electronic ballasts for fluorescent lamps provide a sinusoidal lamp current at the switching frequency. The high-frequency current flowing through the lamp can generate significant radiated noise, which is unacceptable in noise-sensitive applications, such as fluorescent lights in airplanes. Using shielded enclosures for the lamps may solve the problem, but it is expensive. A discontinuous conduction mode (DCM) electronic ballast topology is presented which drives the lamp with line frequency current, just like a magnetic ballast. However, compared to a magnetic ballast, its weight is substantially reduced due to operation at 40 kHz switching frequency. The topology also ensures unity power factor at the input and stable lamp operation at the output     

A Single-Stage High-Power-Factor Electronic Ballast Based on Integrated Buck Flyback Converter to Supply Metal Halide Lamps

In this paper, a novel single-stage electronic ballast with a high power factor is presented. The ballast circuit is based on the integration of a buck converter to provide the power factor correction, and a flyback converter to control the lamp power and to supply the lamp with a low-frequency square-waveform current. Both converters work in discontinuous conduction mode, which simplifies the control. In spite of being an integrated topology, the circuit does not present additional stress of voltage or current in the main switch, which handles only the flyback or buck current, depending on the operation mode. To supply the lamp with a low-frequency square-wave current to avoid acoustic resonances, the flyback has two secondary windings that operate complementarily at a low frequency. The design procedure of the converters is also detailed. Experimental results from a 35-W metal halide lamp are presented, where the proposed ballast reached a power factor of 0.95, a total harmonic distortion of 30% (complying with IEC 61000-3-2), and an efficiency of 90%.     

基于IR2155 的高压钠灯电子镇流器设计

本文针对高压钠灯电子镇流器设计中，开关损耗大、驱动复杂、启动速度慢等问题，提出一种高性能高压钠灯用电子镇流器电路。该电路成功的应用了L6560校正芯片和IR2155专用半桥驱动芯片，即简化了传统的驱动电路，又实现了变频调节，提高了启动速度，保证了灯功率的稳定。通过频率和辅助元件的设置，半桥逆变电路可工作在软开关状态。同时设计出可靠的、能产生3．5kV电压的启动电路，保证灯在热灯熄灭时，切断触发脉冲，而后自动恢复启动状态。实验结果表明该镇流器性能优良，功率因数大于0．99，启动时间小于2.4min。     

Starting control for series-resonant electronic ballast withrapid-start fluorescent lamp

A starting-aid circuit is added to the series-resonant electronic ballast for reducing the glow current in a rapid-start fluorescent lamp during the preheating. By controlling the operating frequency, the electronic ballast provides an adequate filament current for preheating with nearly zero lamp voltage     

Small-signal analysis of a low-cost power control for LCC series-parallel inverters with resonant current mode control for HID lamps

In this paper, a low-cost power control for LCC series-parallel inverters with resonant current mode control for high intensity discharge (HID) lamps is presented. These resonant inverters require controlling the power supplied to the lamp in order to avoid exceeding the maximum lamp power recommended by the lamp manufacturer. The classical control method measures the lamp voltage and current and they are multiplied analogically, obtaining the lamp power consumption measure. This control circuitry results very complex due to the lamp voltage and current wide variations range during ignition and discharge processes. Assuming a regulated input dc voltage (bus voltage) provided by the power factor correction (PFC) pre-regulator and an inverter constant efficiency along the lamp aging, the lamp power consumption may be estimated and regulated properly measuring the inverter average input current. Also, the small-signal analysis performed allows obtaining the small-signal resonant inverter input impedance and studying the connection stability between PFC pre-regulator and inverter. The inverter small-signal analysis has been performed and an electronic ballast prototype for 250-W HPS lamps has been implemented and tested verifying the low-cost lamp power control method proposed.     

Acoustic-resonance-free electronic ballast for automotive HID lamps

A novel cost-effective and acoustic-resonance-free electronic ballast used to drive automotive high intensity discharging (HID) lamps that utilise a constant lamp power control scheme is proposed. The presented ballast is comprised of a buck-boost flyback converter to provide negative DC voltages and a half-bridge-type inverter to supply the lamp with low-frequency, square-wave AC voltage/ current. Owing to its low-frequency operation, no acoustic resonance occurs on the automotive HID lamps. Design guidelines and experimental results are demonstrated for a 35 Wautomotive HID lamp prototype ballast operating at 400 Hz switching frequency with battery input DC voltage of 12 V.     

High Power Factor Self-Oscillating Electronic Ballast to Supply Four Fluorescent Lamps

This paper presents an innovative modification in the conventional self-oscillating driver, in order to supply variable loads. This modification consists of adding an auxiliary output filter supplying a small power resistor, which also includes the primary winding of the self-oscillating transformer. The analysis for self-sustained oscillations is performed by extended Nyquist criterion, which defines the design equations for the ballast component values. A design example is presented, using the proposed circuit in a high power factor electronic ballast supplying four independent lamps. A passive circuit named valley charge pump is used to perform the power factor correction. The ballast supplies four lamps independently, without considerable frequency changes, with an efficiency of 93%, and reaching IEC 61000-3-2 requirements for the input current distortion.     

Novel Automotive High Intensity Discharge(HID) Lamps with Electronic Ballasts

A new scheme of automotive high intensity discharge(HID) lamps with electronic ballasts is proposed. The design of the proposed ballast and some experimental results are presented. The proposed scheme is consisted of the high frequency DC-DC converter and the low frequency DC-AC inverter. This system separates the input voltage of the ignitor from DC link voltage using auxiliary winding, then it could use the lower voltage rating power devices for HID lamp ballast system and reduce the size of HID lamp ballast. The proposed ballast controller using micro-controller unit(MCU) controls the frequency to operate the DC-DC converter in critical conduction mode, which reduces the noise of the circuit and improves the efficiency by 2%~4%.     

Digital Control of a Low-Frequency Square-Wave Electronic Ballast With Resonant Ignition

This paper proposes a two-stage low-frequency square-wave (LFSW) electronic ballast with digital control. The first stage of the ballast is a power factor correction (PFC) stage, and the second is a full-bridge (FB) converter used for both lamp ignition and LFSW drive. As a novelty for LFSW ballasts, ignition is achieved without an additional igniter circuit by operating the FB during start-up as a high-frequency resonant inverter. After ignition, the converter operates as an LFSW inverter to avoid exciting acoustic resonances by controlling the FB as a buck converter and regulating alternately positive or negative current to the lamp. Lamp power is regulated by adjusting the average current supplied by the PFC stage. Another contribution of this paper is to utilize digital control as a simple solution to achieve multimode control, including resonant lamp ignition, LFSW transitions, and lamp current and power regulation.