Single-Stage Led Drivers Based On Integrated Bcm Boost And Llc Converters For Street Lighting

Electrical lighting has been an important technology to modern society. Given the increasing concerns about environmental and energy saving issues, light-emitting-diode (LED) has become the research focus due to the features of mercury elimination and high energy efficiency compared to conventional lamps. Performance aspects of LED lighting are related with LED driver, thus an appropriate converter should be designed to power up the LEDs with good input power factor and high efficiency. To achieve these elements, single-stage alternating current to direct current (AC-DC) converter with power factor correction (PFC) is proposed as LED driver for application in street lighting. In this topology, a pair of boost circuits which share a single inductor are combined as a PFC stage and then integrated with half-bridge LLC resonant converter. Three kinds of rectifier circuits are proposed for the secondary-side rectification; full-wave bridge rectifier, full-wave voltage doubler rectifier and dual half-wave rectifiers. All rectifier circuits have their own advantages and remove the requirement of center-tapped transformer in circuit design. The power switches are driven by a high-voltage resonant controller IC L6598 with nearly 0.5 duty cycle and a small dead time. All proposed LED drivers have been tested in the laboratory for supplying 12 high-power LEDs from ac input voltage of 240-V. From the comparison results, LED driver using full-wave voltage doubler rectifier has shown the best performances, followed by LED driver using full-wave bridge rectifier and then LED driver using dual half-wave rectifiers. The highest power factor measured is almost unity at 0.99, the lowest total harmonic distortion (THD) is 13.8%, the highest efficiency is 93.39% and the lowest bus voltage is 330-V. The power factor correction was successfully achieved and high conversion efficiency was obtained due to soft-switching characteristics of the LED driver. The voltage stress on bus capacitor is considerably reduced to 1.36 times of the input-peak-voltage. The dimming capability was also accomplished. Lastly, the minimization of storage capacitance was successful with an acceptable range of output current ripple for flicker-less LED lighting

A Single-Stage LED Driver Based on ZCDS Class-E Current-Driven Rectifier as a PFC for Street-Lighting Applications

This paper presents a light-emitting diode (LED) driver for street-lighting applications that uses a resonant rectifier as a power-factor corrector (PFC). The PFC semistage is based on a zero-current and zero-derivative-switching (ZCDS) Class-E current-driven rectifier, and the LED driver semistage is based on a zero-voltage-switching (ZVS) Class-D LLC resonant converter that is integrated into a single-stage topology. To increase the conduction angle of the bridge-rectifier diodes current and to decrease the current harmonics that are injected in the utility line, the ZCDS Class-E rectifier is placed between the bridge-rectifier and a dc-link capacitor. The ZCDS Class-E rectifieris driven by a high-frequency current source, which is obtained from a square-wave output voltage of the ZVS Class-D LLC resonant converter using a matching network. Additionally, the proposed converter has a soft-switching characteristic that reduces switching losses and switching noise. A prototype for a 150-W LED street light has been developed and tested to evaluate the performance of the proposed approach. The proposed LED driver had a high efficiency (>91%), a high PF (>0.99), and a low total harmonic distortion (THD i <; 8%) under variation of the utility-line input voltage from 180 to 250 V rms . These experimental results demonstrate the feasibility of the proposed LED scheme

Overview of Passive Light Emitting Diode Driver Circuits for Street Lighting

This paper describes the overview and comparison of various passive Light Emitting Diode (LED) driver circuits employed for street lighting applications. Passive LED driver circuits are constructed with diodes and capacitors without using any power electronic semiconductor switches which in turn eliminates the secondary supply unit for control circuits and controllers. Passive LED driver circuits are simple in construction, low cost, less maintenance and control free. 50 W LED driver circuit is identified for performance comparison and simulations are performed in matlab- simulink to get an overview of different passive LED driver circuits. The most predominant parameters such as efficiency and total harmonic distortion are compared to identify the suitiblity of the driver circuits for various applications

Overview of Passive Light Emitting Diode Driver Circuits for Street Lighting

This paper describes the overview and comparison of various passive Light Emitting Diode (LED) driver circuits employed for street lighting applications. Passive LED driver circuits are constructed with diodes and capacitors without using any power electronic semiconductor switches which in turn eliminates the secondary supply unit for control circuits and controllers. Passive LED driver circuits are simple in construction, low cost, less maintenance and control free. 50 W LED driver circuit is identified for performance comparison and simulations are performed in matlab- simulink to get an overview of different passive LED driver circuits. The most predominant parameters such as efficiency and total harmonic distortion are compared to identify the suitiblity of the driver circuits for various applications

Pregled AC-DC i DC-DC pretvarača za primjene u LED rasvjeti

High-Brightness Light Emitting Diodes (HB-LEDs) are considered the future trend in lighting not only due to their high efficiency and high reliability, but also due to their other outstanding characteristics: chromatic variety, shock and vibration resistance, etc. Nevertheless, they need the development of new power supplies especially designed for boosting and taking advantage of their aforementioned characteristics. Besides, their behaviour is completely different from the rest of lighting devices and, consequently, it should be also taken into account in the design of the converters used to drive them. As a result, many well-known topologies have been optimized or redesigned in order to be used in LED–lighting applications and many new topologies have come up in the recent years with the same purpose. In this paper, the main HB-LED characteristics will be explained, highlighting how they influence the design of their power supplies. After, the main topologies will be presented from the simplest to the most complex ones, analysing their advantages and disadvantages.Svjetleće diode s visokom razinom svjetline (HB-LED) smatraju se budućim trendom u rasvjeti zahvaljujući ne samo visokom stupnju efikasnosti i pouzdanosti, nego i njihovim izvanrednim svojstvima: raznolikost boja, otpornost na udarce i vibracije i sl. Ipak, s ciljem potpunog iskorištenja prethodno spomenutih svojstava, potrebno je razviti nove, posebno osmišljene izvore napajanja. Osim toga, ponašanje im se posve razlikuje od ostalih tipova rasvjete što je potrebno uzeti u obzir pri projektiranju pretvarača za njihovo napajanje. Kao posljedica toga, mnoge su poznate topologije pretvarača optimirane ili preoblikovane posebno za primjenu u LED rasvjeti, a zadnjih nekoliko godina mnoge nove su se tek pojavile. U ovom članku objašnjena su osnovna HB-LED svojstva naglašavajući njihov utjecaj na razvoj izvora napajanja. Uz to, prikazane su osnovne topologije, od najjednostavnijih do najsloženijih, ujedno analizirajući prednosti i nedostatke pojedinih

A Survey, Classification and Critical Review of Light-Emitting Diode Drivers

Based on a survey on over 1400 commercial LED drivers and a literature review, a range of LED driver topologies are classified according to their applications, power ratings, performance and their energy storage and regulatory requirements. Both passive and active LED drivers are included in the review and their advantages and disadvantages are discussed. This paper also presents an overall view on the technical and cost aspects of the LED technology, which is useful to both researchers and engineers in the lighting industry. Some general guidelines for selecting driver topologies are included to aid design engineers to make appropriate choices.published_or_final_versio

A design of LED driver circuit for reducing production cost in Thailand industry

In this paper, the designing of a modified flyback converter circuit for 100 Watts LED lighting has been demonstrated. Some important factors, i.e. efficiency (ɛ), power factor (PF), and total harmonic current distortion (THDi), are considered for interpreting the performance of the proposed circuit. A commercial driver circuit which an efficiency of 94% and price of ∼2,000 THB has, consequently, been employed as a reference circuit. Two experimental setups, performance investigation and cost analysis, have been demonstrated for confirming the concept designed. However, the experimental results shown that an efficiency of the developed driver is 93.93%, while the implementation cost is 1,257 THB respectively. Compared with the reference circuit, we found that the performance of modified flyback circuit is almost equivalent in any parameters, while the cost is cheaper than the reference of 37.15%. This implies that there is a possibility to transfer the knowledge of designing concept to mass production for Thailand industry. In addition, it would thus be reduced the investment cost by the importation driver circuits from other countries and also to support Thailand industry for producing the high quality goods for exporting aboard

Optimization And Design Of Photovoltaic Micro-inverter

To relieve energy shortage and environmental pollution issues, renewable energy, especially PV energy has developed rapidly in the last decade. The micro-inverter systems, with advantages in dedicated PV power harvest, flexible system size, simple installation, and enhanced safety characteristics are the future development trend of the PV power generation systems. The double-stage structure which can realize high efficiency with nice regulated sinusoidal waveforms is the mainstream for the micro-inverter. This thesis studied a double stage micro-inverter system. Considering the intermittent nature of PV power, a PFC was analyzed to provide additional electrical power to the system. When the solar power is less than the load required, PFC can drag power from the utility grid. In the double stage micro-inverter, the DC/DC stage was realized by a LLC converter, which could realize soft switching automatically under frequency modulation. However it has a complicated relationship between voltage gain and load. Thus conventional variable step P&O MPPT techniques for PWM converter were no longer suitable for the LLC converter. To solve this problem, a novel MPPT was proposed to track MPP efficiently. Simulation and experimental results verified the effectiveness of the proposed MPPT. The DC/AC stage of the micro-inverter was realized by a BCM inverter. With duty cycle and frequency modulation, ZVS was achieved through controlling the inductor current bi-directional in every switching cycle. This technique required no additional resonant components and could be employed for low power applications on conventional full-bridge and half-bridge inverter topologies. Three different current mode control schemes were derived from the basic theory of the proposed technique. They were referred to as Boundary Current Mode (BCM), Variable Hysteresis Current Mode (VHCM), and Constant Hysteresis Current Mode (CHCM) individually in this paper with their advantages and disadvantages analyzed in detail. Simulation and experimental iv results demonstrated the feasibilities of the proposed soft-switching technique with the digital control schemes. The PFC converter was applied by a single stage Biflyback topology, which combined the advantages of single stage PFC and flyback topology together, with further advantages in low intermediate bus voltage and current stresses. A digital controller without current sampling requirement was proposed based on the specific topology. To reduce the voltage spike caused by the leakage inductor, a novel snubber cell combining soft switching technique with snubber technique together was proposed. Simulation and experimental waveforms illustrated the same as characteristics as the theoretical analysis. In summary, the dissertation analyzed each power stage of photovoltaic micro-inverter system from efficiency and effectiveness optimization perspectives. Moreover their advantages were compared carefully with existed topologies and control techniques. Simulation and experiment results were provided to support the theoretical analysis

A Single-Stage Dual Output Ac/Dc Converter With Pfc For Supplying Led Light

LED lights have become the most well-known type of lights, owing to their multiple features such as energy saving, long life-span, good luminous efficacy and low maintenance costs. LED lights are suitable for usage in various locations and fields, such as indoor or outdoor locations, and in electric vehicles. The evaluation of the performance of LED light depends on the values taken from measurement of the power factor, efficiency and total harmonic distortion of the LED driver. To achieve good values, a single-stage dual output AC/DC converter with PFC is proposed in this thesis. It can be used as two distinct types of the LED driver. When the relay switch (SWr) state is changed from turned-off (open) to turned-on (closed), the secondary-side of the proposed topology is changed from a full-bridge rectifier (type 1) to a full-bridge voltage doubler rectifier (type 2). The proposed converter consists of one LLC tank and two boost circuits with one shared inductor. The proposed converter is designed to work with 240 VAC, 50Hz single-phase input supply voltage. A high resonant frequency at 100 kHZ and a duty cycle at 48.5% were used for the switches. To simulate the proposed converter, MATLAB Simulink software was utilized. When the output power was at 100 W and the relay switch was open, the power factor, efficiency, total harmonic distortion, and bus voltage were found to be 0.99, 93.3%, 14.53%, and 338 V, respectively. When the output power was at 100 W and the relay switch was closed, the power factor, efficiency, total harmonic distortion, and bus voltage were found to be xx 0.989, 91.8%, 15.17%, and 340 V, respectively. In addition to that, the soft-switching characteristics were also achieved. The MOSFET switches are turned on during zero voltage switching (ZVS) and the secondary output diodes are turned off during zero current switching (ZCS). Furthermore, when the relay switch was closed, the output voltage was twice higher than that when the relay switch was open. This means that smaller current are flowing through the output diodes, output capacitor and transformer, which leads to reducing the stress on these components and potentially increasing their operating lifespan