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     

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.     

Single-stage electronic ballast with dimming feature and unitypower factor

Analysis, design, and practical consideration of a single-stage electronic ballast with dimming feature and unity power factor are presented in this paper. The proposed single-stage ballast is the combination of a boost converter and a half-bridge series-resonant parallel-loaded inverter. The boost semistage working in the discontinuous conduction mode functions as a power factor corrector and the inverter semistage operated above resonance are employed to ballast the lamp. Replacing the lamp with the plasma model, analysis of the ballast is fulfilled. The dimming feature is carried out by pulse-width modulation (PWM) and variable-frequency controls simultaneously. The proposed single-stage ballast is suitable for applications with moderate power level and low-line voltage while requiring a high-output voltage. It can save a controller, an active switch and its driver, reduce size, and possibly increase system reliability while requiring two additional diodes over a conventional two-stage system. A prototype was implemented to verify the theoretical discussion. The hardware measurements have shown that the desired performance can be achieved feasibly     

An electronic ballast with wide dimming range, high PF, and low EMI

The authors describe an electronic ballast design with the capability of low radiated and conducted EMI over a wide dimming range. It overcomes some limitations of traditional electronic ballasts that use frequency variation for dimming control. The proposed design allows soft switching of the ballast from full-power operation down to less than 10% power. Low-cost and low-voltage power metal oxide semiconductor field effect transmitters (MOSFETs) can be used in the proposed dimmable electronic ballast. The design approach is described and implemented successfully in a 2×36 W fluorescent lamp system     

A single-stage electronic ballast with high power factor

A single stage electronic ballast with high power factor (HPF) is proposed in this letter. The single-phase boost-type rectifier provides HPF. A saturable transformer constituting the self-oscillating drive limits the lamp current and dominates the switching frequency of the ballast. Experimental results obtained on a 40 W fluorescent lamp are discussed     

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.     

Multitone signals with low crest factor

After an introductory discussion of real-valued and complex signals, it is shown that minimizing the crest factor (CF) of multitone signals is closely related to the construction of complex sequences with low sidelobes in their aperiodic autocorrelation function. Inspired by this observation, a lower bound on the achievable CF is derived. Four differing algorithms for the reduction of the CF of complex multitone signals are compared with each other by computer simulation. The preferred algorithm is presented in detail, and its convergence is proven. Examples of multitone signals with up to 15 tones and lower CF than previously reported in the literature are given     

Single-switch electronic ballast with near-unity power factor andsoft-switching characteristic

The design and analysis of a single-switch electronic ballast with near-unity power factor and soft-switching characteristic are presented. The ballast circuit is simple and has a small component count. The experimental results for an 80 W ballast show that it has a power factor higher than 0.99 and a total harmonic distortion of 12%. The operating frequency is between 20-40 kHz. The output power is adjustable and the circuit is reliable     

A novel single-stage push-pull electronic ballast with high inputpower factor

A novel single-stage push-pull electronic ballast with high input power factor is presented in this paper. The proposed electronic ballast combines the front-end power-factor corrector and push-pull converter into a single-stage power converter. Compared to the single-stage class-D electronic ballast, the proposed circuit does not require an isolated driver. The control of the circuit is easier and the cost less. The circuit of the ballast is analyzed and the design guidelines are listed. The experimental results verify the theoretical derivation     

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     

电子镇流器无源功率因数校正的实现方法

在电子镇流器及节能灯中,无源功率因数校正电路具有成本低,可靠性好,调试容易等优点,但往往在谐波含量问题上迭不到电磁兼容标准的要求。下面对无源功率因数校正的几种实现方法进行了对比分析,并延深出了一种新的实现方法,可使无源功率因数校正电路的谐波含量降到15％以下,功率因数不小于0．96,满足电磁兼容标准要求,在实际应用中可供借鉴。     

High-power-factor electronic ballast with constant DC-link voltage

This paper presents a high-power-factor (HPF) electronic ballast based on a single power processing stage with constant DC-link voltage. The switching frequency is controlled to maintain the DC-link voltage and the voltage across the switches constant, independently of changes in the AC-input voltage. This control method assures zero-voltage switching (ZVS) for the specified AC-input-voltage range. Besides, with an appropriate design of the fluorescent lamps' drive circuit, the lamps' power can be kept close to the rated value. The power-factor-correction (PFC) stage is formed by a boost power converter operating in the discontinuous conduction mode, which naturally provides HPF to the utility line. The fluorescent lamps are driven by an unmodulated sine-wave current generated from an LC parallel resonant power converter which operates above the resonant frequency to perform ZVS. Theoretical analysis and experimental results are presented for two series-connected 40 W fluorescent lamps operating from 127 V -15% to +10% 60 Hz utility line. The switching frequency is changed from 25 to 45 kHz to maintain the DC-link voltage regulated at 410 V, which leads to a constant output power. The experimental results confirm the high efficiency and HPF of this electronic ballast     

High power factor self-power-controlling electronic ballast usingcurrent source type push-pull resonant inverter

A new simple low cost high power factor correction circuit for electronic ballast employing a current source type push-pull resonant inverter is proposed. The proposed circuit provides high power factor, low current harmonic distortion, self-power-controlling operation for load variations and cost-effectiveness     

Comments on corrections to “An improved design method ofRotman lens antennas”

For original paper by Katagi, Mano, and Sato see ibid., vol.32, no.5, p.524 (1984). Corrections to this paper were suggested by Leonakis (see ibid., vol.34, no.8, p.1067, 1986) and by Singhal and Sharma (see ibid., vol.42, no.7, p.1037, 1994). Katagi et al. here comment on the corrections to their paper. Singhal and Sharma reply to the comments     

Single-stage electronic ballast with class-E rectifier as power-factor corrector

A single-stage high-power-factor electronic ballast with a Class-E rectifier as a power-factor corrector is proposed. A Class-E rectifier is inserted between the front-end bridge rectifier and the bulk filter capacitor to increase the conduction angle of the bridge-rectifier diode current for obtaining low line-current harmonics. The Class-E rectifier is driven by a high-frequency sinusoidal current source, which is obtained from the square-wave output voltage of the Class-D inverter through an LC series resonant circuit. A high-frequency transformer is used for impedance matching. The experimental results for a 32-W prototype ballast are given. The switching frequency was 61.3 kHz. At full power, the power factor was 0.992 and the total ballast efficiency was 88.3%. The lamp-current crest factor was about 1.36. The simulated and experimental results were in very good agreement.     

A novel single-stage high-power-factor electronic ballast with symmetrical topology

This paper proposes a novel single-stage high-power-factor high-efficiency electronic ballast with symmetrical topology for fluorescent lamps. The circuit topology originates from the integration of two half-wave rectifiers with buck-boost power-factor-correction converters and a half-bridge series-resonant parallel-loaded inverter. A high power factor at the input line is assured by operating the buck-boost converters in discontinuous conduction mode. With symmetrical operation and carefully designed circuit parameters, zero-voltage switching on the active power switches of the inverter can be retained to achieve high circuit efficiency. The design equations are derived from the analyzed results based on fundamental approximation, and then an easy-to-use design tool is provided accordingly under considerations of filament heating and ignition. A prototype circuit designed for two T9-40W rapid-start fluorescent lamps is built and tested to verify the analytical predictions. Satisfactory performance is obtained from the experimental results.     

一种改进的安全电子交易协议

引 言 随着网络的普及,电子商务对金融服务行业将产生巨大的影响。付费系统及其相关金融机构将在电子商务领域扮演极其重要的角色。安全电子交易协议(SET)凭其高安全性成为公开网络上最受欢迎的电子付费协议之一。但为了满足众多     

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     

Comments on “An improved method of measuring the power-lineimpedances using two current probes”

The authors of the above paper (see Kwasniok, Kozlowski, and Stuchly, ibid., vol.35, no.4, p. 473-75, 1993) state in the first sentence that the two-current-probe method was developed by Nickleson and Malack (1973) and refer to their paper. During the early 1970s while employed by Southwest Research Institute in San Antonio, TX, I was in charge of an Air Force research project to investigate methods to measure signals being transmitted via power lines. One of the results of my work on this project was the development and testing of methods to measure power-line impedances. I designed an automated system to measure power-line impedance and a set of active current probes     

Analysis and design of a high power factor, single-stage electronic ballast for high-intensity discharge lamps

This paper proposes a single-stage electronic ballast for high-intensity discharge lamps. The ballast consists of the integration of a boost converter in discontinuous conduction mode (DCM) and a full-bridge LCC resonant inverter. The boost semi-stage working in DCM functions as a power factor corrector and the inverter semi-stage operated above resonance is employed to drive the lamp. The sine-wave approximation is used to design the inverter at steady-state. The proposed electronic ballast can save a controller, reduce size and possibly increase system reliability compared to conventional two-stage system. The proposed ballast is analyzed, simulated and experimentally verified with a 125 W HPS lamp.