Provide Power Factor Correction Research Articles

Current Source Strategy for Energy Injection from a CapMix Cell

Circulation of salty and fresh water through the electrodes of a deionization cell produces a voltage between the electrodes caused by the Capacitive Donnan Potential (CDP). The voltage so generated is very low (100 mV), but this work demonstrates that it is possible to develop a power converter suitable to inject this energy into the grid or into energy storage systems; this is a relevant aspect of this paper, for most works in the literature simply dissipate this energy over a resistor. To increase the input voltage, a stack of electrodes is connected in series. A bridgeless rectifier that uses a dual buck–boost converter to operate with both the positive and negative cycles is used to extract the energy from the cell. The topology chosen, which is operated as a current source, can work at extremely low voltage levels and provide power factor correction. After this stage, an H-bridge inverter can be included to inject the energy into the AC grid. The whole system implements a hysteresis control system using the current through the inductor of the power converter as control variable. This paper investigates the influence of such current on the efficiency of the total system.

Power factor correction in power delivery systems with mutipulse nonlinear loads

THE PURPOSE. Мutipulse rectifiers are widely used as a nonlinear loads in industrial distribution systems. The advantage of mutipulse rectifiers is low harmonic emission and high power factor. However input currents of mutipulse rectifiers have a wide spectrum including characteristic and noncharacteristic harmonics. This has a negative impact on the power quality. Shunt capacitors are the simplest form of reactive power compensation in industrial power distribution systems. However power systems with nonlinear loads suffer from severe harmonic distortion due to the parallel resonance between capacitors and system inductance. Special compensating devices for reactive power compensation and correction of power system frequency response for resonances damping are necessary. METHODS. In this paper shunt compensating devices for power delivery systems with multipulse nonlinear loads are considered. Proposed devices are composed of 3-5 order parallel connected passive broadband filters. They provide power factor correction, voltage and current harmonics mitigation and resonance modes damping. A general broadband filter design procedure based on frequency and reactive power scaling of normalized filter parameters is developed. RESULTS. Characteristics of different compensating devices configurations using broadband passive filters are discussed. It is shown that broadband filtering devices enable compensation of fundamental frequency reactive power as well as mitigation of voltage harmonic level to values determined by Russian and international standards. Proposed devices have lower fundamental power losses in c omparing with known solutions. CONCLUSION. Proposed analytical design method is applicable to broadband filters of different orders.

Повышение энергетической эффективности электромеханической трансмиссии карьерного автосамосвала

The article analyzes the existing systems of electromechanical transmission of mining trucks BelAZ. The influence of the load nature created by the uncontrolled rectifier on the power factor and mass-dimensional indicators of the electromechanical transmission isassessed.Variants of modernization of the AC-electromechanical transmission system are proposed, which provide power factor correction. The influence of the proposed options on the overall dimensions of the electromechanical transmission is considered. Based on the assessment, a modernization option was chosen that provides the required power factor with minimal impact on the overall dimensions of the electromechanical transmission.The results of modeling the operation of the existing electromechanical transmission and the modernized electromechanical transmission system using the most promising modernization option are presented.

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.

High-Frequency Isolated AC–DC–AC Interleaved Converter for Power Quality Applications

This paper presents a single-phase ac-dc-ac converter with high-frequency isolation, which employs the interleaved technique. The proposed converter is suitable for power quality applications, such as dynamic voltage restorers, uninterruptable power supplies, and voltage regulators. The modeling of power flow is presented, focusing on the minimization of the transformer current. This analysis is improved by the introduction of the actuators type concept, which ensures reduced current through the transformer. Moreover, the effective longitudinal inductance of the series association of the boost inductor and two interphase transformers is determined. The soft-switching regions are also obtained as well as their dependency on the phase-shift angle. The proposed converter is compared with one indirect ac-dc-ac topology, which uses the dual active bridge converter as the isolation stage. Experimental results are obtained to show that the proposed converter is able to provide power factor correction, mitigate voltage sags, and regulate the output voltage.

Electric Spring for Voltage and Power Stability and Power Factor Correction

Electric spring (ES), a new smart grid technology, has earlier been used for providing voltage and power stability in a weakly regulated/stand-alone renewable energy source powered grid. It has been proposed as a demand-side management technique to provide voltage and power regulation. In this paper, a new control scheme is presented for the implementation of the ES, in conjunction with noncritical building loads like electric heaters, refrigerators, and central air conditioning system. This control scheme would be able to provide power factor correction of the system, voltage support, and power balance for the critical loads, such as the building's security system, in addition to the existing characteristics of ES of voltage and power stability. The proposed control scheme is compared with original ES's control scheme where only reactive power is injected. The improvised control scheme opens new avenues for the utilization of the ES to a greater extent by providing voltage and power stability and enhancing the power quality in the renewable energy powered microgrids.

Single-Switch Soft-Switched Boost Power Factor Corrector for Modular Applications

Modern dc power supplies provide power factor correction but the classical two-stage approach, using hard-switched preregulators, has detrimental effects on efficiency and reliability, particularly for high power applications. With some circuit modifications and the addition of a few magnetic components, diodes and capacitors, we have turned a classical boost power factor corrector into a high efficiency soft-switched version. The proposed converter turns on its single switch with zero current and turns it off with zero voltage. In this paper we explain the proposed changes, we study the waveforms and equations and we verify them with an experimental prototype. We also show how the converter can be used for modular single- and three-phase high power applications.<br /><br />

Control and Modulation of Bidirectional Single-Phase AC–DC Three-Phase-Leg SPWM Converters With Active Power Decoupling and Minimal Storage Capacitance

In a single-phase grid-connected nanogrid system, a bidirectional ac–dc converter is usually required to transfer energy between the ac grid and a dc bus. Active ac power balancing is often implemented to prevent the ac grid ripple power from injecting into the dc bus. A four-phase-leg sinusoidal pulsewidth-modulation (SPWM) converter can readily provide power factor correction and active ac power balancing. In this paper, the use of three-phase-leg SPWM converters for achieving these functions is analyzed. A family of bidirectional single-phase ac–dc three-phase-leg SPWM converters with an ac storage capacitor for use in a nanogrid system is designed with a general control structure and a modulation scheme for minimizing the ac storage capacitance. The general control structure is designed to achieve a decoupled system of a power-factor-correction converter cascaded with an active ac power load at the dc bus. The decoupled system is developed based on decomposition to differential-mode and common-mode voltages. The modulation method involves an extra zero-sequence voltage injection derived from the three-phase-leg SPWM voltages without introducing higher order harmonic distortions. A significant reduction of the ac storage capacitance and an improvement of converter efficiency are achieved. The design and analysis are verified by simulations and experimental measurements.

English

This Project proposes a new algorithm to generate reference voltage for a distribution static compensator (DSTATCOM) operating in voltage-control mode. The proposed scheme exhibits several advantages compared to traditional voltage-controlled DSTATCOM where the reference voltage is arbitrarily taken as1.0 p .u. The proposed scheme ensures that unity power factor (UPF) is achieved at the load terminal during nominal operation, which is not possible in the traditional method. Also, the compensator injects lower currents and, therefore, reduces losses in the feeder and voltage-source inverter. Further, a saving in the rating of DSTATCOM is achieved which increases its capacity to mitigate voltage sag. Nearly UPF is maintained, while regulating voltage at the load terminal, during load change. The state-space model of DSTATCOM is incorporated with the deadbeat predictive controller for fast load voltage regulation during voltage disturbances. The state-space model of DSTATCOM is incorporated with the deadbeat predictive controller for fast load voltage regulation during voltage disturbances. With these features, this scheme allows DSTATCOM to tackle power-quality issues by providing power factor correction, harmonic elimination, load balancing, and voltage regulation based on the load requirement. Simulation and experimental results are presented to demonstrate the efficacy of the proposed algorithm.

A Novel Approach for Design and Analysis of Voltage-Controlled DSTATCOM for Power Quality Enhancement

The Power quality fluctuations of the distributed power system show a serious impact on the robust and sustainable operation of the distributed power system. These power quality fluctuations may be caused due to several reasons like leakage, faults and ageing of the lines. This project proposes a new algorithm to generate reference voltage for a controlled mode distribution static compensator (DSTATCOM) operating in voltage-control mode. The proposed scheme exhibits several advantages compared to traditional voltage-controlled DSTATCOM where the reference voltage is arbitrarily taken as 1.0 p.u. The proposed scheme ensures that unity power factor (UPF) is achieved, while regulating the voltage at the load terminal, during load change, which is not possible in the traditional method. Also, the compensator injects lower currents and, therefore, reduces losses in the feeder and voltage-source inverter. This scheme allows DSTATCOM to tackle power-quality issues by providing power factor correction, harmonic elimination, load balancing, and voltage regulation based on the load requirement. Simulation and experimental results are presented to demonstrate the efficacy of the proposed algorithm.

A Novel Approach for Design and Analysis of Voltage- Controlled DSTATCOM for Power Quality Enhancement

The Power quality fluctuations of the distributed power system show a serious impact on the robust and sustainable operation of the distributed power system. These power quality fluctuations may be caused due to several reasons like leakage, faults and ageing of the lines. This project proposes a new algorithm to generate reference voltage for a controlled mode distribution static compensator (DSTATCOM) operating in voltage-control mode. The proposed scheme exhibits several advantages compared to traditional voltage-controlled DSTATCOM where the reference voltage is arbitrarily taken as 1.0 p.u. The proposed scheme ensures that unity power factor (UPF) is achieved, while regulating the voltage at the load terminal, during load change, which is not possible in the traditional method. Also, the compensator injects lower currents and, therefore, reduces losses in the feeder and voltage-source inverter. This scheme allows DSTATCOM to tackle power-quality issues by providing power factor correction, harmonic elimination, load balancing, and voltage regulation based on the load requirement. Simulation and experimental results are presented to demonstrate the efficacy of the proposed algorithm.

English

In recent years, power converters are used to get high power factor for low power applications. In this work, the design and development of a DC-DC Converter using two stage buck–boost converter with isolation operation as high-power-factor offline power supply for power-LED lamps is discussed. This converter is suitable for low power application such as a matrix LED lighting system. The advantage of this converter is that instead of using two controlled switches as in case of a conventional converter, this circuit uses one MOSFET as a switch. The circuit uses two inductors and two capacitors as energy transferring elements that are able to provide a good quality, high efficiency power supply to the load. The design of this converter is simulated with closed loop control using a PI controller circuit. The main feature of this circuit is that have a galvanic isolation between the load and the source. Thus, by a suitable controller and galvanic isolation, the ripple magnitude in the output is reduced considerably. A design example for a 70-W converter supplied from a 230 V/50 Hz mains for street lighting applications is shown. Simulation results demonstrate that the power factor of the closed-loop proposed converter is 0.993 and the output voltage of the designed controller can be stably maintained at 200V. The experimental results are shown to substantiate this design. This converter is used to provide power factor correction in streetlight application. The simulation studies using MATLAB/Simulink is also presented.

A Voltage-Controlled DSTATCOM for Power-Quality Improvement

This paper proposes a new algorithm to generate reference voltage for a distribution static compensator (DSTATCOM) operating in voltage-control mode. The proposed scheme exhibits several advantages compared to traditional voltage-controlled DSTATCOM where the reference voltage is arbitrarily taken as 1.0 p.u. The proposed scheme ensures that unity power factor (UPF) is achieved at the load terminal during nominal operation, which is not possible in the traditional method. Also, the compensator injects lower currents and, therefore, reduces losses in the feeder and voltage-source inverter. Further, a saving in the rating of DSTATCOM is achieved which increases its capacity to mitigate voltage sag. Nearly UPF is maintained, while regulating voltage at the load terminal, during load change. The state-space model of DSTATCOM is incorporated with the deadbeat predictive controller for fast load voltage regulation during voltage disturbances. With these features, this scheme allows DSTATCOM to tackle power-quality issues by providing power factor correction, harmonic elimination, load balancing, and voltage regulation based on the load requirement. Simulation and experimental results are presented to demonstrate the efficacy of the proposed algorithm.

Digital Control Strategy for HID Lamp Electronic Ballasts

This paper presents the analysis, design, simulation and experimental results of a digital control strategy applied to an electronic ballast to supply a 70-W high-pressure-sodium lamp. The electronic ballast consists of a single-stage converter that integrates a buck converter to provide power factor correction and two flyback converters to supply the lamp, with low frequency square waveform, in order to avoid the acoustic resonance phenomenon occurrence. The proposed digital control strategy is composed of three control loops: voltage loop for lamp ignition and warm-up, an inner current loop for steady state, and a slow outer power loop to maintain the lamp power constant during its useful life. The lamp dynamic model is included to the ac model of the converter, so the effects of its right-half-plane zero are considered to design the digital control system. Fixed-point simulation is presented using Q base number format, where the exact variable values employed in the microcontroller code are used. Experimental results are included to demonstrate the performance of the proposed digital control strategy.

Microcontroller-Based High-Power-Factor Electronic Ballast to Supply Metal Halide Lamps

The analysis, design, and implementation of a microcontroller-based electronic ballast to supply metal halide (MH) lamps are presented. The proposed topology is based on the integration of the buck and flyback converters, the former providing power factor correction and the latter controlling lamp power. The lamp is supplied by a low-frequency square-waveform current, which is a convenient way to avoid acoustic resonances in high-intensity discharge lamps. Both converters operate in discontinuous conduction mode, thus allowing the use of only one high-frequency switch and simplifying the control. The electronic ballast is digitally controlled by using a low-cost microcontroller PIC16F684. The microcontroller performs all the necessary tasks during starting, warming-up, and steady state, including closed-loop control of lamp current and protections. The closed-loop control takes into account the lamp dynamical impedance. Experimental results for a 35-W MH lamp are presented, and the obtained overall efficiency is 90%.

Electronic Ballasts for HID Lamps

This article presents a general analysis of several integrated topologies with high power factor in supplying metal halide (MH) lamps. The analyzed topologies that provide power-factor correction (PFC) are buck, boost, buck-boost, flyback, sepic, and zeta converters. The design methodology employed to calculate the circuit parameters and the simulation results are also presented.

Projeto e implementação de um reator eletrônico microcontrolado, de elevado fator de potência, orientado a lâmpadas de vapor metálico

Este trabalho descreve a análise, o projeto e a implementação de um reator eletrônico para lâmpadas de vapor metálico (MH) baseado em microcontrolador. O circuito do reator se fundamenta na integração de um conversor buck com um conversor flyback. A tarefa de correção do fator de potência é realizada pela etapa buck, enquanto a etapa flyback controla a potência na lâmpada fornecendo uma corrente em onda quadrada de baixa freqüência. Este é um método adequado para se evitar o fenômeno da ressonância acústica, comum em lâmpadas de descarga de alta pressão (HID). Os dois estágios conversores operam no modo de condução descontínua (DCM), o que permite o uso de apenas um interruptor de alta freqüência simplificando o controle. O reator eletrônico é controlado digitalmente e emprega um microcontrolador de baixo custo PIC16F684. Este componente é programado para desempenhar todas as tarefas necessárias aos processos de ignição, aquecimento e regime permanente da lâmpada, respondendo também pelo controle em malha fechada da corrente na lâmpada e proteções convencionais. O artigo inclui resultados experimentais obtidos de um protótipo que alimenta uma lâmpada MH de 35W.

Dynamic and Steady Behavior of Harmonic Filter for Compensating Resonance in Mining Systems

Process integration and automation in mining facilities require systems engineering involving electronics, information technologies, telecommunication, computer-based devices and power electronics control for a broad range of functions. Electronics controllability has evolved with power converter-based systems for material handling and mineral ore processing. However, power converters introduce harmonics and EMC/EMI emissions, affecting the reliability of sensitive and important electronic systems, stating a current challenge for a proper design of electrical systems in mining facilities, because increasing complexity due to combination and interaction of weak networks, high-power equipment, variable structure and non-linear loads with harmonic current injections. Harmonic filters are commonly used to provide power factor correction and limiting the harmonic distortions. This paper highlight the capability of harmonic filters to give a stationary and dynamic behavior that can be employed for compensating resonances of electrical systems in order to avoid unwanted transient phenomena like overvoltages. Modeling and simulation results obtained for a typical system with switching operations depict the good correlation between steady and transient behavior, supporting the results given by tools intended for stationary analysis of harmonics performance. Different operating conditions of an industrial power system given by variable topology, multiple harmonic injections and loading factor should be taken into account for the proper design of harmonic filters systems. This work presents a methodology for supporting the risk assessment and decision making process at the design stage of power systems, in order to avoid failures, improving design and reliability.

A Soft-switched Pwm Interleaved Boost-flyback Converter With Power Factor Correction

This paper proposes a soft switching interleaved Boost-Flyback converter employed as a preregulator stage providing power factor correction. The use of a soft commutation cell allows the main switches to be turned on and off under null current and null voltage conditions, respectively. Interleaving techniques imply the overall reduction of the Boost inductor size and also the minimization of the switching losses without increasing voltage and current stresses. This topology has the advantages of the Flyback converter, as auxiliary power supplies are not necessary. A theoretical analysis, including the description of the operating stages and relevant expressions is developed. Additionally, simulation and experimental results are presented.

Circuit theory of power factor correction in switching converters

AbstractThis paper discusses the circuit theory aspects of power factor correction in switching converter circuits. The discussion begins with an examination of the requirement of power factor correction in dc/dc converters. Using the concept of zero‐order converter circuits, sufficient conditions for a dc/dc converter circuit to provide power factor correction are derived. The duality principle is applied to generate new converter circuits that can achieve power factor correction. The practical application of power factor correction is considered in conjunction with the requirement of tight output voltage regulation. Detailed study of the circuit configuration that can simultaneously provide power factor correction and output regulation is given. Based on a general three‐port model, the voltage regulator with power factor correction capability is studied in terms of the power flow between the input port, output port and energy storage port. A detailed consideration of the power flow among the three ports leads to the derivation of all possible minimal configurations that can achieve power factor correction and voltage regulation. The efficiencies of these minimal configurations are studied theoretically, leading to the concept of ‘reduced redundant power processing’ which provides important clue to efficiency improvement. Another issue addressed in this paper is the synthesis of practical circuits that can provide power factor correction and output regulation. In particular, four practical minimal configurations that achieve reduced redundant power processing are considered. A systematic synthesis procedure is derived for creating converter circuits that achieve power factor correction and output voltage regulation. The control issue is also investigated in depth, pinpointing the basic requirement on the number of control parameters needed and its relationship with the operating mode. Copyright © 2003 John Wiley & Sons, Ltd.