Factor Correction Technique Research Articles

From dim to glow: dynamic illuminance adjustment for simultaneous exposure correction and low-light image enhancement

Acquiring high-quality images in diverse lighting conditions is challenging, particularly in the constantly evolving driving landscape. From the harsh brilliance of daylight to the subtle shadows of nighttime scenarios, the complexity of capturing accurate images intensifies. Therefore, addressing exposure issues across various lighting conditions is imperative. This study introduces a novel multi-task end-to-end dynamic illumination adjustment approach termed CPGA-DIA. By incorporating feature selection and gamma factor correction techniques, our method effectively handles extreme variations in light conditions for both low-light image enhancement and exposure correction. Comprehensive experimental evaluations demonstrate superior performance to existing processes, showcasing our method’s adaptability and robustness in real-world driving scenarios. Furthermore, our approach extends its capabilities to include the control and estimation of explainable factors related to changing lightness, enabling our model to understand better the environmental conditions that influence image perception and clarity. This research contributes to advancing image capture methodologies, particularly in dynamic lighting conditions, with promising implications for applications ranging from photography to various other fields.

Design and Implementation of Single-Phase Boost PFC Converter

In this paper, a single-phase boost type ac-dc converter with power factor correction (PFC) technique is designed and implemented. A current mode control at a constant switching frequency is used as a control strategy for PFC converter. The PFC converter is a single-stage singleswitch boost converter that uses a current shaping technique to reshape the non-sinusoidal input current drawn by the bulky capacitor in the conventional rectifier. This technique should provide an input current with almost free-harmonics, comply with the IEC61000-3-2 limits, and a system operates with near unity power factor. The other function of the boost converter that should beaccomplished is to provide a regulated DC output voltage. The complete designed system is simulated in MATLAB/SIMULINK and a hardware prototype has been built using analog devices. Simulation results and experimental results are presented to validate the proposed system.

Adaptive Controller for Bridgeless New SEPIC Integrated Landsman Converter for PFC in Induction Motor

The Induction Motor (IM)when powered by an AC supply, results in low power factor because of excessive harmonic contents, which is effectively minimized by adopting proper Power Factor Correction (PFC) technique. This paper proposes an AC-DC bridgeless SEPIC-Landsman converter for a 3ϕVoltage Source Inverter (VSI) fed IM to perform effective PFC and power quality enhancement at AC supply mains. Here, the bridgeless SEPIC-Landsman converter’s switching operation is controlled by the adaptive Proportional Integral (PI) controller for getting a controlled DC output voltage with minimum ripples. A Cascaded Type 2 Fuzzy Logic Controller (CT2FLC) effectively controls speed of the IM and also reduces the peak overshoot problem. Here, the speed control is achieved by adjusting voltage and frequency of 3 IMwith a reduced settling time of 0.2s. The proposed system is modeled with MATLAB Simulink and empirically validated, generating a THD value of 1.69% and an efficiency of 93%. The simulation and hardware results thus obtained confirm an effectiveness and reliable performance of the proposed system.

Analysis and Demonstration of Control Scheme for Multiple Operating Modes of Energy Storage Converters to Enhance Power Factor

Rectifiers are required by the devices connected to the distribution end of the electrical power networks for AC/DC conversion. The line current becomes non-sinusoidal when a capacitor with a significant value is used to mitigate the output voltage ripple. This type of converter emulates a non-resistive impedance to the grid, due to which a bend occurs in the shape of the line current, which results in high total harmonic distortion and a low power factor. For perceiving sinusoidal current, power factor correction techniques are required. A digital controller for parallel-connected buck-boost power factor correctors is presented in this article to maintain a constant output voltage and to deal with circulating currents amongst parallel-connected converters. The proposed digital supervisory controller also regulates the input and line currents to keep them sinusoidal according to the input supply voltage to maintain the high power factor of the system. In this paper, using the differential equations of a buck-boost converter, the duty cycle calculations are performed for both Continuous Conduction Mode (CCM) and Discontinuous Conduction Mode (DCM), which are responsible for providing a unity power factor. A supervisory controller encompasses a feed-forward control algorithm for tuning model parameters for eliminating the harmonics from the line current. The proposed scheme helps calculate duty cycles which provides a unity power factor and minimizes the circulating currents. The proposed method was simulated in MATLAB/Simulink and their digital-hardware validation testing was also performed using C2000 MCU Launchpad.

DESIGN AND IMPLEMENTATION OF POWER FACTOR CORRECTION MODEL IN HYBRID SYSTEM

Good quality power along with efficient supply system is the need of ours in past few decades. Making power generation system more ecofriendly use of renewable sources of energy was promoted. To attain this implementation of hybrid mode (solar photovoltaic system) of power supply came forward, main issue arose was degrading power factor the main reason of this was the incapability of PV system to supply reactive power. This could however be compensated by implementing various power factor correction techniques. Out of all such methods capacitor compensation method is efficient to overcome this may it be an industry or a home. KEYWORDS: Power quality, Solar, inverter, Power Factor.

Implementation of Boost PFC in the Induction Heating System for EMI–RFI Suppression

The present work deals with the design and performance analysis of high frequency resonant inverter based Induction Heating (IH) System employing Boost Power Factor Correction (PFC) technique to overcome the problems due to EMI and RFI. Most of the existing techniques use passive filters for harmonics attenuation that fails to meet the present day requirement because of drawbacks like considerably high THD, poor dynamic performance, etc. This paper presents a new control approach for boost PFC based on inner and outer loops to eliminate the problems due to harmonics in the IH system. The equivalent circuit parameter model of the IH system has been used to analyze the presence of harmonics and the incorporation of boost PFC at the input of the system shows its elimination as per the stringent EMI-RFI regulations. Moreover, attention has been paid off to the design algorithm of the boost PFC and a detailed mathematical analysis has been done to outline an approach for its parameter selection. A comparative analysis of the IH system with and without the incorporation of the boost PFC has been done in terms of the THD in the input current waveform. The findings of the present work show that the incorporation of Boost PFC eliminates the harmonics in the IH system in a better manner than the existing techniques. Doi: 10.28991/HIJ-2021-02-02-05 Full Text: PDF

Análise experimental de indicadores de qualidade de energia de lâmpadas LED E27 residenciais disponíveis no mercado brasileiro

With advances in energy demand, investments in energy efficiency and power quality are increasingly important. One of the extensively adopted measures is the replacement of fluorescent lamps by LED lamps. This measure contributes to the increase of energy efficiency, but produces a high load of current harmonics, which may cause degradation in power quality indicators of the electric distribution networks, due to the presence of rectification electronic circuits present in such lamps. In this work, several models of LED lamps available in the Brazilian market were tested for harmonic and power factor production, taking as reference the standards Inmetro 389/2014, 143/2015 and 144/2015. Applying the Fast Fourier Transform (FFT) the modules and phases of each harmonic component in the currents were measured. Subsequently, the total harmonic distortion (THD) of the current in each lamp was calculated and the estimated total power factor. The results obtained were compared with the nominal values of the lamps and the circuit of four of the lamps was analyzed. It was verified that only six models out of the twenty-three analyzed had THD below 100% and of the analyzed models, 61% did not meet the nominal technical specifications regarding the power factor, and that Power Factor Correction (PFC) techniques present in some of the models were responsible for adjusting the lamps to the regulation parameters.

Power Factor Correction in Feeders With Distributed Photovoltaics Using Residential Appliances as Virtual Batteries

Thermostatically controlled residential appliances have built-in thermodynamic storage that, even within a narrow temperature band that does not degrade the comfort level of occupants, can be used to provide a variety of value streams to power system operators and customers. In this paper, residential air conditioners and electric water heaters are used to improve feeder power factor in a distribution system where photovoltaic systems cause the feeder power factor to dip daily, increasing losses. Improving distribution feeder power factor improves the efficiency of the transmission and bulk generation systems. A daily optimal dispatch regime is used to maximize the daily minimum feeder power factor. Following this regime, electric water heaters cool off in preparation for a low-feeder-power-factor event, turn on to improve the power factor during the event and return to a neutral condition after the event. Air conditioners, which have a power factor lower than the feeder overall, are optimally dispatched in the inverse pattern. Using a model of a real commercial and residential distribution feeder in the western United States, the optimal dispatch of virtual batteries is shown to be capable of improving the daily minimum power of that feeder by as much as 0.026. The power factor correction and optimal dispatch techniques are based on a robust virtual battery framework, making them portable to other applications, such as volt-var optimization and transactive energy systems.

DESIGN AND SIMULATION OF AUTOMATIC POWER FACTOR CORRECTION FOR INDUSTRY APPLICATION

In the present technological revolution power is very precious. So we need to find out the causes of power loss and improve the power system. Due to industrialization the use of inductive load increases and hence power system losses its efficiency. So we need to improve the power factor with a suitable method of automatic power factor correction. This study undertakes the design and simulation of an automatic power factor correction that is developed using arduino microcontroller ATmega328 Automatic power factor correction device reads power factor from line voltage and line current. This time values are then calibrated as phase angle and corresponding power factor. The display used was 4X16 liquid crystal display module. The motherboard calculates the compensation requirement and accordingly switches on different capacitor banks will run. This automatic power factor correction technique can be applied to the industries, power systems and also households to make them stable and due to that the system becomes stable and efficiency of the system as well as the apparatus increases. The use of microcontroller reduces the costs and the customers become beneficial according to the simulated output because the power factor of the specific selected industry is corrected from 0.66 to 0.92 improved value.

Güç Kaynakları İçin Yüksek Verimli Güç Faktörü Düzeltme Devresi Tasarımı

Designing power factor correction circuits for switched power supplies has become important in recent years in terms of efficient use of energy. Power factor correction techniques play a significant role in high power density and energy efficiency. For these purposes, bridgeless PFC topologies and control strategies have been developed alongside basic boost PFC circuits. The power density can be increased using bridgeless structures by means of reducing losses in the circuit. This article examines bridgeless PFC structures and compares their performances in terms of losses and power factor. A semi-bridgeless PFC, which is widely used at high power levels, was analyzed and simulated. The designed circuit simulation using the current mode control method was performed in the PSIM program. A prototype of a 900 W semi-bridgeless PFC circuit was implemented and the results obtained from the circuit are presented

Design and development of improved power quality based micro‐butt welding power supply

This study proposes a suitable DC–DC converter topology with improved power quality at the input side for micro-butt welding machine by evaluating different power factor correction (PFC) techniques and DC–DC converter topologies. Firstly, different control strategies of boost converters such as peak current controlled PFC, average current controlled PFC and hysteresis current controlled PFC are discussed for minimising input current distortions and improving the power quality. Also, the current loop gain stability analyses are presented using small-signal model for selecting the best model and optimisation of the same. Secondly, the important key parameters such as cost, size, weight, complexity in implementation and other application dependent parameters of various isolated type of DC–DC converter topologies are compared and the best DC–DC converter topology is selected for the proposed application. Finally, the modelling and stability analysis is performed on the DC–DC converter and optimisation is achieved for the welding current controller. The software packages MATLAB/Plecs/OrCAD PSpice are used for simulation and implementation of the desired circuitry with optimised design. A prototype has been developed based on optimised design, hysteresis current controller for PFC and DC–DC converter; and the control algorithm is implemented DSP TMS320F2812 and the experimental results were discussed.

인덕터 전류검출이 필요없는 불연속모드 인터리브드 PFC 부스트 컨버터의 연구

A light-emitting diode (LED) has been increasingly applied to various industrial fields and general lightings because of its high efficiency, low power consumption, environment-friendly characteristic and long lifetime. To drive this LED lighting, various types of power converters have been applied. Also, power factor correction (PFC) techniques play an important role in the power supply technology. In this paper, design and control of a DCM interleaved boost PFC converter is discussed. The proposed converter can reduce current ripples at input and output side by cancelling an each phase of inductor currents. Since the IC does not require the auxiliary winding of inductor for current detection, simple PFC circuit is achieved. Therefore, it contributes to increase efficiency and downsize the whole system volume, cost. Also, the performance of the proposed system is demonstrated through experiments.

Hardware Implementation of Single Phase Power Factor Correction System using Micro-controller

Rapid increase of consumers in electronics devices and the use of mains rectification circuits inside these electronic devices is the root cause of mains harmonic distortion. Automatic power factor correction techniques can be applied to the industries, power systems and households to make them stable inturns increases the efficiency of system as well as the apparatus. This paper deals with the hardware design of active power factor correction circuit employing boost converter which is used to boost the DC voltages with a controller based on PID control strategy. The pulses given to power switches by pulse width modulation techniques generated by utilizing micro-controller board, Arduino thus obviating the need of complex hardware circuitry. MATLAB/SIMULINK was used to design and tune the PID controller parameters. The simulation results are matching with the predictions and the same was implemented as hardware. The waveforms various test points and across capacitors were obtained, studied and compared with the theoretical waveforms and are found to be in precise proximity of theoretical waveforms.

The Effects of Total Harmonics Distortion for Power Factor Correction at Non-Linear Load

This paper presents the effect of total harmonic distortion (THD) in power factor correction (PFC) at non-linear load. This study focuses on the relationship between THD and PFC. This is beacuse,the power factor affects THD. This occurs in power system as we have variety of loads, i. e linear load or non-linear load. The variety of loads will influence the sinusoidal waveform, which comes out from harmonic distortion. Thus, based on this study, we can compare the effective method in improving the power factor as it will not disturb the performance of THD. The focus of study is on the single phase load, where the voltage restriction is 240 V. The analysis will only focus on the consumer, which depends on the variety of non-linear load. Besides, the parameters for analysis are based on the percentage of THD and the value of power factor. The instrument for measuring the parameter is based on power factor correction device or technique. On the other hand, the method that was used for this study is based on simulation which incorporated the Multisim software. At the end of ths study, we can choose the most effective method that can be used to improve the power factor correction without disturbing the THD.

Review in Power Factor Correction Techniques

With the development of industries the inductive load is extremely increased due to the uses of induction motors. In the inductive circuit the current lags behind the applied voltage. The inductive load in a transmission line or in a circuit causes low power factor and as a result high current flows through that circuit and a large voltage drop occurs in it, so a greater energy loss occurs due to the heat dissipation. To reduce this power loss the power factor should be improved. Power factor lies between 0 and 1. For maximum utilisation of active power, power factor should be near to unity. There are various methods to improve power factor. In this paper the “power factor correction” is discussed and the determination of the KVAR ratings for the capacitor are explained. After an exhaustive review process, one key issue is found that is-“the method of switching on and off the capacitors”. The outcome of the review was in the form of various findings, found under the key issue. The overall target is the improvement in power factor, which is advantageous for both the suppliers of electricity as well as the consumers.

Development of an Automatic Identification System Autonomous Positioning System.

In order to overcome the vulnerability of the global navigation satellite system (GNSS) and provide robust position, navigation and time (PNT) information in marine navigation, the autonomous positioning system based on ranging-mode Automatic Identification System (AIS) is presented in the paper. The principle of the AIS autonomous positioning system (AAPS) is investigated, including the position algorithm, the signal measurement technique, the geometric dilution of precision, the time synchronization technique and the additional secondary factor correction technique. In order to validate the proposed AAPS, a verification system has been established in the Xinghai sea region of Dalian (China). Static and dynamic positioning experiments are performed. The original function of the AIS in the AAPS is not influenced. The experimental results show that the positioning precision of the AAPS is better than 10 m in the area with good geometric dilution of precision (GDOP) by the additional secondary factor correction technology. This is the most economical solution for a land-based positioning system to complement the GNSS for the navigation safety of vessels sailing along coasts.

Iterative reliability-based modified majority-logic decoding for structured binary LDPC codes

In this paper, we present an iterative reliability-based modified majority-logic decoding algorithm for two classes of structured low-density parity-check codes. Different from the conventional modified one-step majority-logic decoding algorithms, we design a turbo-like iterative strategy to recover the performance degradation caused by the simply flipping operation. The main computational loads of the presented algorithm include only binary logic and integer operations, resulting in low decoding complexity. Furthermore, by introducing the iterative set, a very small proportion (less than 6%) of variable nodes are involved in the reliability updating process, which can further reduce the computational complexity. Simulation results show that, combined with the factor correction technique and a well-designed non-uniform quantization scheme, the presented algorithm can achieve a significant performance improvement and a fast decoding speed, even with very small quantization levels (3–4 bits resolution). The presented algorithm provides a candidate for trade-offs between performance and complexity.

Simulation and Practical Analysis on Power Factor Correction Techniques for Welding Applications

The most of the industrial welding applications involving of electronic circuits such as AC-DC, and DC-AC and AC-DC converters. The input power factor of such a system is reduced due to the presence of more harmonics due to the non-linear devices within the converters which leads to creates more adverse effects. There by a need of suitable AC-DC converter with power factor correction technique to condition the supply current. The power factor correction rectifier that requires best current control from i) Peak current control ii) Average current control and iii) Hysteresis current control. This paper presents a comparative analysis from above mentioned power factor correction control topologies. The simulation of these control techniques are carried out using “Plecs” with “MATLAB/SIMULINK”. The simulation results shows that Hysteresis control has low THD, good DC link voltage regulation and better performance than other control techniques. The same control technique is implemented in TMS320F2812 DSP and results are proved.

Single Phase AC-DC Converter Employing PowerFactor Correction with High Frequency IsolationUsing Buck-Boost PWM Converter

In single phase AC-DC converter employing power factor correction here we intend to produce a programmable power supply those whose output voltage can be varied as per user requirement. The paper propose the power factor correction technique, single phase active power factor correction, circuit configurations and results for the single phase AC-DC converter.

Reliability-based iterative proportionality-logic decoding of LDPC codes with adaptive decision

In this paper, we present a reliability-based iterative proportionality-logic decoding algorithm for two classes of structured low-density parity-check (LDPC) codes. The main contributions of this paper include: 1) Syndrome messages instead of extrinsic messages are processed and exchanged between variable nodes and check nodes, which can reduce the decoding complexity; 2) a more flexible decision mechanism is developed in which the decision threshold can be self-adjusted during the iterative process. Such decision mechanism is particularly effective for decoding the majority-logic decodable codes; 3) only part of the variable nodes satisfying the pre-designed criterion are involved for the presented algorithm, which is in the proportionality-logic sense and can further reduce the computational complexity. Simulation results show that, when combined with factor correction techniques and appropriate proportionality parameter, the presented algorithm performs well and can achieve fast decoding convergence rate while maintaining relative low decoding complexity, especially for small quantized levels (3-4 bits). The presented algorithm provides a candidate for those application scenarios where the memory load and the energy consumption are extremely constrained.