Enhancing Power Factor on LED Light Driver with Boost and Fly Back Converter Integration

Abstract

This paper describes the practical application of a power converter in order to enhance the power factor of an LED light driver. The power converter employed in this system is a combination of a boost converter and a fly back converter. The power factor correction functionality of the boost converter is achieved by the implementation of discontinuous conduction mode operation, which enables the converter to function as a resistive converter. Hence, in the case of a rectifier circuit providing power to a resistive load, the current flowing back to the source will exhibit the same waveform as the voltage. Consequently, this results in a power factor value close to unity (1). Based on the findings of the conducted experiment, it has been seen that the use of the BIFRED converter as a driver for LED lamps yields a notable enhancement in power factor, elevating it from 0.84 to 0.98. Furthermore, it has been determined that this particular driver circuit adheres to the prescribed line-current harmonic thresholds established by the IEC61000-3-2 class C standards.

Introduction

I. INTRODUCTION

Currently, there is a significant advancement in technology, shown by the emergence of low-power LED lights that offer high luminosity. LED lights have been widely implemented globally and have had a substantial influence on reducing power consumption. Regrettably, the LED light is categorized as a non-linear load, hence having the potential to diminish the power factor. Consequently, an apparatus is required to rectify or enhance the power factor. The operation of an LED lamp often necessitates the utilization of a driver circuit, which comprises a rectifier responsible for converting an alternating current (AC) voltage source into a direct current (DC) voltage. One commonly employed rectifier configuration is the single-phase full wave rectifier circuit. Within this electrical circuit, there exists a capacitor of significant magnitude that serves the purpose of functioning as a filter. Its primary role is to diminish the occurrence of output voltage ripple. Nevertheless, the incorporation of a capacitor into a rectifier circuit has the potential to induce distortion in the input current and prevent the waveform from assuming a sinusoidal shape. Additionally, the integration of this technology results in an augmented quantity of current harmonics being introduced into the electrical grid [1], therefore leading to a diminished power factor. The issues of high harmonic distortion and poor power factor are of significant concern in the field of electric power supply. Therefore, it is necessary to undertake certain measures in order to address this issue.

The best solution to address this difficulty is to put a converter as power factor improvement on LED light, it is called power factor correction (PFC) Converter. As a result, the PFC converter has emerged as a significant concern. Power factor may be increased with a variety of converters, all of which can go close to 1 in terms of efficiency. Due to the widespread prevalence of issues with the degradation of power factor caused by non-linear loads, research into methods of power factor correction is rapidly progressing. The soft-switching AC-DC power factor correction converter is one form of power factor correction study that focuses on the topic of improving power factor through the use of soft switching. Integration of a renewable energy source on the input side and the usage of an inverter to serve non-linear loads for power factor enhancement via passive control are also part of the development process. Studies showing increased efficiency from power factor enhancement utilizing the frequency multiplier approach provide credence to this hypothesis. In addition, successful tests of a novel design for boosting the power factor from alternating current to direct current have been conducted. The next step in power factor improvement was accomplished with a single-stage wireless-power transfer resonant converter that incorporated bridgeless power boost factor correction by employing a rectifier as a nonlinear load.

Power factor improvement has reached the smart grid system. Smart grid is a research topic that is currently and will likely develop very quickly. By utilizing power factor correction to enhance residential smart grid systems, the power factor in these systems can be improved.

In terms of mitigating power quality in unidirectional AC-DC, power factor enhancement through flexible control may be implemented to influence power quality. Power corrected zeta converters can be used to improve power quality in switch mode power supply (SMPS) systems. Applications for LED lamps are used in single-phase systems with less processing in daily life all across the world. More precisely, there are two types of power converters that may be used to increase the power factor: one-stage and two-stage PFC circuits. A two-stage PFC circuit is made up of two converters linked in series, one for use as a PFC and the other for a dc regulator. The second kind of PFC circuit is a one-stage PFC, which may be used as both a PFC and a dc regulator. It combines two converters into a single stage. A two-stage PFC circuit differs from a one-stage PFC circuit in that it uses fewer components, cheaper costs, and a better level of converter efficiency. In order to raise power factors, a variety of two-stage converters are employed, including flyback, sepic, and boost converters. Boost-flyback converter (BIFRED), flyback-forward converter, and flyback-boost (flyboost) are a few of the single-level converters that have been released for PFCs.

The use of the BIFRED converter as an LED light driver will be covered in this article. The BIFRED converter consists of a flyback converter that may operate in either continuous conduction mode (CCM) or discontinuous conduction mode (DCM) and a boost converter that functions as a power factor correction converter (CCM). The BIFRED converter can be used as a BLDC motor driver, for example.  In order to fulfill the line-current harmonic restrictions established by IEC61000-3-2 class C [23], as indicated in Table 1, the BIFRED converter is applied to lighting loads (LED lights) and presented in this work.

II. METHOD OF RESEARCH

The framework for this investigation is the system design delineated in the block diagram comprising the workflow of the system. Figure 1 illustrates a comprehensive summary of the application of the BIFRED converter in order to enhance the power factor of LED lamp loads.  In order to minimize the number of components, costs, and complication issues associated with two-stage converters, one of the proposed converters is the BIFRED (boost integrated flyback rectifier energy storage DC-DC) converter. Figure 2 illustrates the circuit of the LED lamp driver utilizing the BIFRED converter.

For PFC input and output voltage regulation, a BIFRED Converter (shown in Figure 2) integrates boost-flyback converters into a single stage (single-switch) and a single controller. The input stage of a BIFRED converter is a flyback converter, which is used to establish the output voltage, and the output stage is a Boost Converter, which uses discontinuous conduction to function as PFC. The two levels share a same active switch. The output capacitor (Co) only experiences the low-frequency (e.g. 100Hz) switching ripple, while the energy storage capacitor (Cb) experiences both the low- and high-frequency switching ripple. Since there is just one switch and one control circuit, this setup has the potential to be inexpensive. Power factor correction (PFC) using a boost converter on a BIFRED circuit is seen in Figure 3, and its associated inductor current waveform is depicted in Figure 4. The input resistance (rs) of this modeled Boost converter is determined by the input voltage and input current during a single switching phase.

Conclusion

The use of a power converter for an LED light driver\'s Power Factor Correction (PFC) circuit has already been covered in this work. The BIFRED converter, which operates in DCM-CCM mode, is what the system relies on for its conversion needs. The BIFRED converter combines the functions of a boost-flyback converter and a voltage regulator in a single device, consisting of a single switch and a single controller. With the BIFRED converter acting as Power Factor Correction (PFC), the power factor of a notional resistive load was raised from 0.89 to 0.99, while that of a 12 V, 48 W LED bulb was raised from 0.84 to 0.98. On both loads, this driver circuit fulfills the line-current harmonic restrictions established by IEC61000-3-2 class C.

References

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Copyright

Copyright © 2023 Dr. A. Gowthaman, Er. K. Arulmozhi. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.