PLL control scheme for the electronic ballast with a current-equalization network

This paper proposes a phase-locked loop (PLL) control scheme for the electronic ballast with a current-equalization network. The PLL control scheme involves detecting the phase signals of both the resonant-tank input voltage and the two leakage-inductor terminals in the transformer; then the operating frequency of the circuit continuously tracks the resonant frequency as a reference frequency. Based on the tracked reference frequency, the required voltage gain of the resonant tank is regulated by offsetting the operating frequency. Consequently, the operating frequency is lower than the resonant frequency to ensure the zero-voltage-switching (ZVS) condition for less turn-on switching losses on the switches. This paper presents the analysis of the proposed PLL control scheme. Finally, the current-equalizing ability in the dimming range is demonstrated by experiments in order to validate and demonstrate the performance and feasibility of the proposed circuit.     

一种E类驱动单级式电子镇流器的仿真研究

提出了一种E类驱动结构的谐振式电子镇流器,将E类结构和buck-boost功率因数校正结构整合成一种单级式电子镇流器。由于E类驱动式的谐振电路只需一个开关管,经过整合后的电路也只需一个控制电路和一个开关管,进一步降低了镇流器的成本提高了效率。文章分析了E类镇流器电路工作在最佳情况下的工作状态,仿真采用脉宽调制控制电路工作。     

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.     

A Three-Phase Dimmable Lighting System Using a Bidirectional Power Electronic Transformer

This paper presents a single-stage bidirectional power electronic transformer (PET) for lighting systems as a three-phase electronic ballast. The lighting system supplies multilamp units that are controlled simultaneously by a bidirectional PET using a pulsewidth modulation scheme. The PET contains a single-input multioutput high-frequency isolating transformer to control the illumination of the lamps as well as providing galvanic isolation in each unit simultaneously. The high-frequency operation, direct ac to ac conversion, and bidirectional power flow capabilities help the PET to operate without any bulky storage elements. So good efficiency, and low weight, volume, and cost of the power conversion system can be achieved. The control strategy promotes the ballast performance to let fluorescent lamps operate free from both voltage flicker and disturbances. As a result, improved dimmable illumination, lamps protection, and increasing lifetime of lamps can be achieved. A design procedure based on equivalent circuit is presented to determine the resonant output circuit parameters. The experimental results of the prototype, which converts 110 V/3phi/50 Hz input voltage to 130 V/1phi/25 kHz and 70 V/1phi/25 kHz output voltages, show the practical aspects of the proposed PET.     

一种用于投影光源的高性能电子镇流器

提出了一种用于投影光源的高性能电子镇流器.主电路采用无源无损的缓冲电路,减小了由于续流二极管反向恢复所引起的开通损耗,提高了镇流器的效率.以数字控制器为核心,结合模拟方式的PWM控制,实现了恒功率控制.分析了镇流器的工作原理并给出了实验结果,实验结果表明该镇流器具有电路简单、可靠性高的优点,实验样机的效率达到了94%.     

具有低能耗辅助电路的三相谐振极逆变器

为优化三相逆变器的效率,提出了一种具有低能耗辅助电路的三相谐振极逆变器,其各相桥臂上分别设置了辅助电路.在辅助电路工作时,主开关可实现零电压软切换,辅助开关可实现零电流软切换,使开关损耗明显降低.此外,在辅助电路的谐振状态结束之后,谐振电感中的剩余电能将只通过1个二极管回馈给储能电容,降低了电能回馈时的辅助电路损耗,有...     

Design and analysis of an IC-less self-oscillating series resonant inverter for dimmable electronic ballasts

This paper presents a low-cost solution of converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable dc current source from the resonant inductor in the resonant tank to control the operating point of the saturable transformers for driving the switches in the inverter. The overall implementation does not require any integrated circuit. A 17-W prototype has been built and studied. Theoretical predictions have been verified with experimental results. The lamp can be dimmed down to 10% of the full power.     

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     

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.     

Power factor correction circuit for low-cost electronic ballastusing current-source type push-pull resonant inverter

A new low-cost high power factor correction circuit for electronic ballast employing current-source type push-pull resonant inverter (CS-PPRI) is proposed. The proposed circuit provides good power factor correction, low current harmonic distortion and cost-effectiveness. The prototype meets the IEC555-2 requirements satisfactorily     

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%).     

Acoustic-Resonance-Free High-Frequency Electronic Ballast for Metal Halide Lamps

To avoid the acoustic resonance on operating metal halide lamps, an autofrequency-searching method is implemented on the high-frequency electronic ballast. The proposed method allows the use of a high-frequency electronic ballast, making the ballast able to adjust the operating frequency automatically as soon as the acoustic resonance is detected and, consequently, to locate it at a stable frequency. The electronic ballast achieves a high efficiency and a high power density through the employment of a high-frequency resonant inverter with an embedded buck-boost converter for power-factor correction and lamp power regulation. The control strategy is realized by a microprocessor along with the acoustic-resonance detection circuit. The operation of autofrequency searching is illustrated by the experiments on an electronic ballast designed for 70-W metal halide lamps.      

Self-oscillating dimmable electronic ballast for fluorescent lamps

This letter presents a low-cost solution for converting the popularly adopted nondimmable electronic ballast circuit for fluorescent lamps with self-oscillating series resonant inverter into a dimmable one. The dimming function is achieved by increasing the switching frequency of the inverter from the natural frequency of the resonant tank, so that less energy is coupled to the lamp. Control of the switching frequency is based on deriving an adjustable dc current source from the inductor in the resonant tank to control the operating point of the saturable chokes for driving the switches in the inverter. The overall circuit does not require any integrated circuit. A 17-W prototype has been built and tested. Theoretical predictions have been verified with experimental results. The lamp can be dimmed to 10% of the full brightness.     

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     

Design and Implementation of a Single-Stage High-Frequency HID Lamp Electronic Ballast

We present a single-stage electronic ballast with a high power factor feature for driving high-intensity discharge (HID) lamps. A new frequency-modulation technique is proposed to eliminate the acoustic resonance problem in HID lamps under high-frequency operation. The proposed method has the merits of simple circuit and low cost; thus, it is suitable for use in commercial applications. The conducted emission caused by the high-frequency electronic ballast can be also effectively reduced. The operating principles and design considerations of the proposed electronic ballast are analyzed and discussed in detail. A 35-W laboratory prototype is designed and implemented. Simulation and experimental waveforms are given to verify the feasibility of the proposed method. The results are satisfactory.     

High-efficiency low-stress electronic dimming ballast for multiplefluorescent lamps

An electronic dimming ballast with a lead-lag tank operation (LLTO) having the properties of high efficiency and low stress is introduced in this paper. The ballast is configured with a voltage-fed half-bridge series-resonant parallel-loaded inverter (SRPLI) acting as a lamp driver. It is loaded with resonant tanks which are designed and operated to be capacitive and inductive to theoretically achieve both zero-voltage switching (ZVS) and zero current switching (ZCS) and to eliminate the reactive current circulating through the switches, resulting in low switching and conduction losses. Moreover, the merit of a successive lamp ignition can be attained with the proposed operation scheme so that current stress imposed on the switches can be reduced. With the plasma model of fluorescent lamps, the analysis, operating principle, and dimming control strategy of the electronic ballast are described in detail. On the other hand, the limitations of the proposed scheme are pointed out. Computer simulation results and experimental measurements are used to verify the theoretical prediction and analytical discussion     

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。     

具有软开关功能的三相谐振直流环节逆变器

为实现三相逆变器节能运行,提出一种具有软开关功能的三相谐振直流环节逆变器.直流侧的辅助谐振电路将参与换流过程,使直流环节电压在桥臂上的主开关动作之前变化到零,主开关能完成零电压软切换动作,通过降低开关损耗来实现逆变器节能运行.分析了1个开关周期内的电路工作流程.实验结果显示开关器件动作时处于软切换.因此,该辅助谐振电路结构对于研发节能型三相逆变器具有参考价值.     

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.     

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%,