High Input Power Factor Research Articles

Achieving high input power factor for DCM Buck PFC converter by variable Duty-Cycle control

Achieving high input power factor for DCM Buck PFC converter by variable Duty-Cycle control

Double Integrated-Buck Boost Converter versus Double Integrated-Buck Topology for LED Lamps

In this paper a comparative study between two different approaches for LED driving based on the double integrated buck boost and a double integrated Buck converter. It presents a single-stage, single-switch, transformer less ac/dc converter suitable for Led lighting applications. High Brightness Light Emitting Diodes (HB LEDs) can be seriously considered for replacing conventional halogen, incandescent and fluorescent lamps in general illumination including streetlights due to the rapid development in LED technology in recent years. In many offline applications, maintaining a high-power factor and low harmonics are of primary importance. Single stage power factor pre-regulation technology is mainly preferred in cost sensitive applications where power factor regulation is necessary, as adding additional power factor correction controller will surely increase the cost. Here a high-power-factor, long life integrated converter able to supply LED lamps from ac mains is presented. This topology integrates a buck-boost type power-factor correction (PFC) cell with a buck–boost dc/dc converter there by providing the necessary high input power factor and low Total Harmonic Distortion (THD). An isolation transformer increases complexities in the implementation of feedback and control. The proposed topology is non-isolated and hence much simpler in implementation. The main advantage of this converter is that this circuit uses only one controllable switch. The converter is used to provide power factor correction in streetlight application. A Double integrated buck converter finds application in fields of solid-state lighting. Buck Converter is widely used for step down dc-dc conversion when there is no isolation requirement. The narrow duty cycle of the buck converter limits its application for high step-down applications. The double integrated buck converter overcomes its limitation. This converter also provides high power factor and output current regulation. A Double integrated buck converter uses for the offline power supply for LED lighting based on the integration of a buck power factor corrector (PFC) and the tapped buck dc/dc converter having high step-down capability and good output current regulation. Due to the high reliability, the simple structure, and the low component count, the proposed topology effectively results to be very suitable for medium power solid-state lighting applications. From Comparative analysis of two circuits integrated double buck boost converter is found to be more efficient with high power factor and low THD.

A Current-Source 5-Level DC-DC Used for Capacitor-less LED Driver

Traditional lighting emitting diode (LED) driving circuits generally use electrolytic capacitors as the filter component, and the lifetime of electrolytic capacitor becomes the main limiting factor for extending the lifetime of LED lighting. Therefore, this paper proposes a new current-source 5-level DC-DC circuit to construct the LED driver. It can not only remove large electrolytic capacitors to improve the service life of LED driver, but also the high input power factor can be achieved by 5-level PWM modulation. Finally, the feasibility and effectiveness of such LED driver are verified by simulation results.

Real time FPGA Implementation of PWM Chopper Fed Capacitor Run Induction Motor

<span>This paper presents the performance enhancement of capacitor run induction motor by pulse width modulated AC chopper.The phase angle control faces severe shortfall in the performance improvement for larger triggering angles. In this paper the comparison of phase angle control and sinusoidal pulse width modulation technique is encountered for effective speed control of single phase capacitor run induction motor. The necessary parameters are taken into considerations are higher efficiency, lesser total harmonic distortion and high input power factor. The results are compared by using the simulations using matlab Simulink environment. The validation of result in hardware is implemented using Field programmable gate array for sinusoidal pulse width modulation technique.</span>

Real time FPGA Implementation of PWM Chopper Fed Capacitor Run Induction Motor

<span>This paper presents the performance enhancement of capacitor run induction motor by pulse width modulated AC chopper.The phase angle control faces severe shortfall in the performance improvement for larger triggering angles. In this paper the comparison of phase angle control and sinusoidal pulse width modulation technique is encountered for effective speed control of single phase capacitor run induction motor. The necessary parameters are taken into considerations are higher efficiency, lesser total harmonic distortion and high input power factor. The results are compared by using the simulations using matlab Simulink environment. The validation of result in hardware is implemented using Field programmable gate array for sinusoidal pulse width modulation technique.</span>

Three-Phase Grid-Connected WECS With Mechanical Power Control

This paper presents a grid-connected wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG) operating with variable speed. Considering that the wind has intrinsic intermittent nature, it is desirable to maximize the extracted energy, as a maximum power point tracking (MPPT) strategy is described for this purpose. Otherwise, the MPPT algorithm is disabled to maintain the rated power condition and avoid damage to the PMSG, as an external mechanical power control loop associated to active stall is introduced in this work, whose power extraction characteristic is similar to that obtained with pitch control. The WECS employs a bridgeless boost rectifier, which provides power factor correction using self-control strategy, with the advantages of reduced conduction losses, simplified drive circuitry for the active switches, and high input power factor without the need to use multipliers in the control system and impose a sinusoidal reference to the input current unlike average current mode control. Connection with the power grid occurs through a three-phase full-bridge inverter, as experimental results on a 6-kW prototype are presented and discussed in detail in order to validate the proposed approach.

Matrix Converter Based Open-End Winding Drives With Common-Mode Elimination: Topologies, Analysis, and Comparison

Matrix converter based open-end winding drives modulated with rotating vectors eliminate the high-frequency common-mode output voltage that could otherwise cause motor failure. Unlike back-to-back converters, no intermediate dc bus capacitor is required—better power density and reliability may, therefore, be achievable. A high voltage transfer ratio and input power factor control capability put these open-end winding drives at a significant advantage over conventional matrix converters. At least three realizations of the matrix converter based open-end drive are possible. This paper compares these three realizations to identify the best topology and presents experimental results validating its capabilities. Filter optimization, loss-optimal vector sequences, and other practical considerations are also discussed. Finally, a comparison with the state-of-the-art back-to-back converters is provided to investigate if the potential improvements are in fact attainable.

Design and analysis of an integrated LC3–Valley fill passive LED driver

ABSTRACTHigh Brightness Light Emitting Diodes (HBLEDs) replace conventional lamps due to energy savings. LC3 parallel resonance principle is used to reduce the total harmonic distortion (THD) for passive LED drivers. The Valley fill concept is applied to reduce the output voltage ripple of LED driver. This paper presents the design and analysis of an integrated LC3–Valley fill passive LED driver suitable for HBLEDs. Valley fill approach is added with LC3 characteristics to further enhance the performance of the LC3-based LED driver. The proposed LED driver achieves high input power factor, low THD with reduced ripple in the output voltage. The integrated passive LED driver consists of inductors, capacitors and diodes only without using any semiconductor-based switching devices and control circuitry. A 70 W driver circuit using single-phase, 230 V, 50 Hz, ac supply is implemented to verify the theoretical analysis. Performance comparison of the integrated LC3–Valley fill passive LED driver is carried out with the existing passive LED driver topologies. An energy efficiency exceeding 95% is obtained.

Single-Phase LED Drivers With Minimal Power Processing, Constant Output Current, Input Power Factor Correction, and Without Electrolytic Capacitor

High-power light-emitting diodes (LEDs) having properties of high luminous efficacy and long life span are becoming a major light source for general illumination. To fully utilize the advantages of LED in lighting applications, the offline power supply that drives the LED should possess the following features: high efficiency, long life span, high input power factor, and (COC). In this paper, high efficiency is achieved by using a minimal power processing (MPP) configuration. Near perfect power factor correction (PFC) is achieved by a simple dual-output disc-ontinuous-conduction-mode (DCM) pulse-width-modulated (PWM) front-end converter. One output of the front-end converter is connected to the LED load using a control switch. The other output is connected directly to a dc storage capacitor cascaded with a downstream DCM PWM converter driving the same LED load to achieve COC driving. The power flow is controlled to achieve the required MPP that can also reduce the storage capacitance by balancing only the ac input ripple power and the dc output power without power recycling. Thus, the design requires no electrolytic capacitor, hence extending the system life span. The achievement of input PFC, MPP, and COC requires design tradeoff among design freedom, ease of control and component count. LED drivers having all these properties are developed, designed, and tested.

Design of an Inductor-less Direct AC-AC Converter Realizing 1/4x and 4x Conversion

In this paper, an inductor-less direct AC-AC converter realizing 1/4x and 4x conversion is designed by using switched-capacitor (SC) techniques. Unlike conventional SC AC-AC converters, the proposed AC-AC converter is synthesized with two converter blocks. By converting an AC input twice by these converter blocks, the 1/4x step-down / 4x step-up conversion is achieved by the proposed converter. The proposed converter has a simple circuit configuration, where each converter block consists of only four bidirectional switches and two capacitors. Hence, the proposed converter can realize smaller circuit components and higher input power factor than conventional converters. The effectiveness of the proposed converter was confirmed by simulation program with integrated circuit emphasis (SPICE) simulations and theoretical analysis. The SPICE simulation revealed that the proposed converter outperforms the conventional AC-AC converter using a flying capacitor.

Semibridgeless Interleaved PFC Boost Rectifier for PHEV Battery Chargers

ABSTRACT In this paper, a new semi-bridgeless interleaved (SBLIL) boost rectifier topology as front end converter for plug-in hybrid electric vehicle (PHEV) is proposed. The proposed rectifier topology achieves higher efficiency, with high input power factor and less power drawn from the utility. A detailed principle of operation and analytical modelling of the converter is presented. The converter prototype is designed for 300 W with a high switching frequency of 80 kHz and tested for a universal input voltage of (110–240) V to get the desired output voltage of 400 V. The modified converter topology achieves a high efficiency of 97% as it eliminates the bridge rectifier and addition of slow diodes. The performance of the proposed converter is compared with the existing standard topologies. The experimental results infer that the power factor at the supply end is 0.99 with THD less than 5% when the load is varied from half load to full load condition.

Inverter Power Control Based on DC-Link Voltage Regulation for IPMSM Drives Without Electrolytic Capacitors

DC-link electrolytic capacitor critically affects the lifetime of the motor drive system. This paper proposes an inverter power control strategy based on dc-link voltage regulation for the electrolytic capacitor-less interior permanent magnet synchronous motor drive system. The dc-link electrolytic capacitor is replaced by a small film capacitor and the power factor correction circuit is also eliminated. Hence, the inverter power should be regulated effectively to achieve high input power factor and low grid current harmonics. The inverter power control loop based on proportional resonant (PR) controller is established to regulate the inverter power into sinusoidal wave. The PR controller can be designed to achieve a high gain at the desired frequency and the parameters are easy to design due to the simple structure. In addition, a power compensation method based on the dc-link voltage regulation is used to diminish the error of inverter power control, which does not depend on the precise calculation and is easy to realize. The effectiveness of the proposed method is demonstrated by the experimental results on an air conditioner. The input power factor can reach 0.992 and the harmonics of grid current are considerably lower than the requirement of EN61000-3-2 standard.

Investigation of Power Quality Improvement in Super Lift Luo Converter

<p align="justify">This paper presents the improved single phase AC-DC super lift Luo converter for enhancing quality of power by mitigating the issues. The proposed converter is used for output voltage control, power factor improvement and reduced source current harmonics at supply side. The main intention of this work is to design appropriate closed loop controllers for this AC-DC super lift Luo converter to achieve unity power factor in the source end. The designed control system comprises of two control loops, voltage control in outer loop and the current controller is devised in the inner loop. Fuzzy controller is used for current controller whereas PI controller as voltage controller. In the MATLAB/SIMULINK platform, simulation of the proposed AC-DC super lift Luo converter is done. It is clear from the simulation results that PI integrated fuzzy controller for voltage and control is proven to be better than classical PI with hysteresis controllers. The proposed system is able to achieve high input power factor along with supply current harmonic distortions of less than 5%.</p>

Analysis and Design of a Single-Stage Isolated AC–DC LED Driver With a Voltage Doubler Rectifier

In order to reduce the cost and volume of small-medium power ac–dc light-emitting diode (LED) lighting systems, single-stage LED drivers are often used to drive LEDs with constant current. In this paper, a single-stage isolated high-power factor ac–dc LED driver is proposed and analyzed in detail, which is composed of a buck–boost power factor correction unit operating in discontinuous conduction mode and an isolated dc/dc unit with a voltage doubler rectifier, and the two units are integrated together by sharing the same power switch. Very high input power factor is achieved since the PFC unit operates with almost fixed duty ratio during half period of the utility line voltage. Since a voltage doubler rectifier is included in the isolated dc/dc unit, magnetic core size of the transformer and voltage stress of the secondary side diodes are reduced remarkably. First, the operating principle and performance of the LED driver are analyzed. Then, the main parameters are quantitatively calculated out in detail. Finally, a comparative analysis is presented and a 120 W experimental prototype with 1 A output current is built according to the calculated parameters and the experimental results are presented to verify the correctness of the theoretical analysis and parameter design.

Variable-On-Time Control to Achieve High Input Power Factor for a CRM-Integrated Buck–Flyback PFC Converter

A variable-on-time (VOT) control scheme for a critical conduction mode (CRM) integrated buck–flyback power factor correction (PFC) converter with high power factor (PF) and low total harmonic distortion (THD) is proposed in this paper. By utilizing the input and output voltage to modulate the on-time of both buck and flyback switches, the input current harmonics can be eliminated and high PF will be obtained. The operating principles of both the conventional constant-on-time (COT) control and VOT control for the CRM buck–flyback PFC converter are analyzed. A 100-W prototype has been built and tested in the lab. The experimental results demonstrate that the THD and PF of the converter with VOT control are greatly improved compared to those with COT control.

Study on Three-phase Six-switch Buck-type Rectifier of High Power Factor

This paper proposed a three-phase six-switch buck-type APFC rectifier based on DSP28335. At present, the boost-type power factor correction rectifier has the advantages of high input current power factor and low harmonic distortion. However, it has the disadvantages of high EMI common-mode noise, and the high output voltage also produces negative effect to the DC-DC converter. This paper designed a three-phase six-switch buck-type APFC circuit, which has no shortcomings of the boost-type power factor correction rectifier, but retains the advantages of the boost-type rectifier, which has high input power factor, low harmonic distortion, low output voltage and low EMI common-mode noise. In addition, it has a high conversion efficiency. Finally a 117V input, 60V/138 watts output device is produced for verification.

Design of a Simple Inductor-less AC-AC Converter Realizing High Input Power Factor

Switched capacitor (SC) techniques is used in order to design a simple inductor-less ac-ac converter with small size and high input power factor. Comparing conventional inductor-less ac-ac converters with the proposed converter, an input/ output (I/O) terminal is connected alternately to one of capacitors to achieve ac-ac conversion. To realize the new topology, the new designed converter is composed of two capacitors and four switches in the conversion ratios of 2 and 1/2. For this reason, as well as high input power factor, the proposed converter can achieve small size. To explain how the proposed converter is operated with the conversion ratios of 2 and 1/2, operation’s law, analysis in theory, and results of circuit simulation are written on this paper. The validity of the proposed converter is confirmed by circuit simulations using SPICE simulator.

Improved resettable integrator control for a bridgeless interleaved AC/DC converter

Plug-in hybrid electric vehicles (PHEVs) consist of a front-end boost rectifier, which incorporates a power factor correction (PFC) circuit for battery charging. Bridgeless interleaved (BLIL) PFC boost converter topology is proved as a standard PFC converter as it has high efficiency, reduced input current ripple, and reduced electromagnetic interference (EMI). This paper proposes a digital nonlinear control technique that employs a resettable integrator to shape the input current of the converter in phase with the input voltage to achieve high input power factor. This control approach rejects power source and load perturbations better than linear feedback control methods. This is accomplished by summing up the sensed input current of a BLIL converter with a fictitious current synthesized with the input voltage. In this work, a BLIL converter is analyzed for its input power factor improvement, voltage stress across the devices, and dynamic response under variable supply and load conditions using simulation. The hardware is tested for a 300 W BLIL boost converter to validate the simulated results. The performance of the proposed controller is compared with that of conventional average current mode control. The experiment and simulation results prove that the resettable integrator controller shows a better performance than the conventional controller.

Single‐stage QR AC–DC converter based on buck–boost and flyback circuits

In this study, a single-stage quasi-resonant (QR) AC–DC converter based on buck–boost and flyback circuits is proposed. The forestage buck–boost circuit works in discontinuous conduction mode to achieve a high-input power factor (PF), and the backstage flyback converter, working in QR mode, is responsible for energy transfer. The QR switch mode can improve the efficiency of the converter by decreasing the switch turn-on losses. The single-stage topology can reduce the cost and raise the reliability of the system. The detailed design process is described in this study, and a 50 W prototype was developed that has a maximum PF higher than 0.99 and a maximum efficiency of 90.91% in nominal working conditions.

Single Stage–Single Switch High Power Factor Long Lifetime AC-DC Driver for High-power White Light-emitting Diodes in Streetlight Applications

To achieve the main advantages of individual high-power white light-emitting diodes, light-emitting diode drivers should feature a high power factor, high efficiency, and a long lifetime. In streetlight applications, due to the inconvenience in reaching out to light-emitting diode fixtures for replacing out-of-order drivers, the durability (long lifetime) of drivers plays an important part in designing lighting products. In this article, a new integrated, single-stage single-switch AC-DC driver for high-power white light-emitting diodes featuring high efficiency, a high power factor, and a long lifetime for streetlight applications is proposed. The single power switch of the proposed driver operates in a non-floating manner without a need for any snubber circuits due to proper inherent operation, which makes the driver simple and reliable. To verify accurate operation of the driver as well as validate the analysis and design procedure discussed herein, a 35-watt light-emitting diode fixture is first simulated in PSIM software (PowerSIM Inc., USA), and then a laboratory prototype is implemented. Simulation and experimental results verify proper performance, high input power factor, and validity of the analysis and the design procedure adopted in the process.