Single-phase Power Factor Correction Research Articles

An FPGA-based Fully Digital Controller for Boost PFC Converter

This paper introduces a novel digital one cycle control (DOCC) boost power factor correction (PFC) converter. The proposed PFC converter realizes the FPGA-based DOCC control approach for single-phase PFC rectifiers without input voltage sensing or a complicated two-loop compensation design. It can also achieve a high power factor and the operation of low harmonic input current ingredients over universal loads in continuous conduction mode. The trailing triangle modulation adopted in this approach makes the acquisition of the average input current an easy process. The controller implementation is based on a boost topology power circuit with low speed, low-resolution A/D converters, and economical FPGA development board. Experimental results demonstrate that the proposed PFC rectifier can obtain a PF value of up to 0.999 and a minimum THD of at least 1.9% using a 120W prototype.

A Three-Level Quasi-Two-Stage Single-Phase PFC Converter with Flexible Output Voltage and Improved Conversion Efficiency

This paper presents a three-level quasi-two-stage single-phase power factor correction (PFC) converter that has flexible output voltage and improved conversion efficiency. The proposed PFC converter features sinusoidal input current, three-level output characteristic, and a wide range of output dc voltages, and it will be very suitable for high-power applications where the output voltage can be either lower or higher than the peak ac input voltage, e.g., plug-in hybrid electric vehicle charging systems. Moreover, the involved dc/dc buck conversion stage may only need to process partial input power rather than full scale of the input power, and therefore the system overall efficiency can be much improved. Through proper control of the buck converter, it is also possible to mitigate the double-line frequency ripple power that is inherent in a single-phase ac/dc system, and the resulting load end voltage will be fairly constant. The dynamic response of this regulation loop is also very fast and the system is therefore insensitive to external disturbances. Both simulation and experimental results are presented to show the effectiveness of this converter as well as its efficiency improvement against a conventional two-stage solution.

Analysis and design of a boost PFC converter with sample-and-hold control techniques

SUMMARY This paper proposes a simple control scheme for single-phase power factor correction (PFC) regulators, which provides the advantages of low current harmonic distortion and rapid transient response. Moreover, the proposed scheme needs only to add two sample-and-hold control circuits into the feed-forward voltage loop and feedback-voltage loop of PFC regulators. Accordingly, the system is not influenced by the 120-Hz ripple voltage but improves the transient response time and input current harmonic distortion. The operating principles and control scheme are analyzed in detail. A 300-W boost power factor corrector prototype is implemented to verify the feasibility of the proposed scheme. The experimental results are satisfactory. Copyright © 2014 John Wiley & Sons, Ltd.

Design and real time implementation of single phase boost power factor correction converter

This paper presents a real time implementation of the single-phase power factor correction (PFC) AC–DC boost converter. A combination of higher order sliding mode controller based on super twisting algorithm and predictive control techniques are implemented to improve the performance of the boost converter. Due to the chattering effects, the higher order sliding mode control (HOSMC) is designed. Also, the predictive technique is modified taking into account the large computational delays. The robustness of the controller is verified conducting simulation in MATLAB, the results show good performances in both steady and transient states. An experiment is conducted through a test bench based on dSPACE 1104. The experimental results proved that the proposed controller enhanced the performance of the converter under different parameters variations.

Unity power factor Converter based on a Fuzzy controller and Predictive Input Current

This paper proposes analysis and control of a single-phase power factor corrector (PFC). The proposed control is capable of achieving a unity power factor for each DC link voltage or load fluctuation. The method under study is composed of two intelligent approaches, a fuzzy logic controller to ensure an output voltage at a suitable value and predictive current control. The fuzzy controller is used with minimum rules to attain a low cost. The method is verified and discussed through simulation on the MATLAB/Simulink platform. It presents high dynamic performance under various parameter changes. Moreover, in order to examine and evaluate the method in real-time, a test bench is built using dSPACE 1104. The implantation of the proposed method is very easy and flexible and allows for operation under parameter variations. Additionally, the obtained results are very significant.

Analysis and Design of a PFC AC-DC Converter with Electrical Isolation

This study presents a single-phase power factor correction AC–DC converter that operates in discontinuous conduction mode. This converter uses the pulse-width modulation technique to achieve almost unity power factor and low total harmonic distortion of input current for universal input voltage (90 Vrms to 264 Vrms) applications. The converter has a simple structure and electrical isolation. The magnetizing-inductor energy of the transformer can be recycled to the output without an additional third winding. The steady-state analysis of voltage gain and boundary operating conditions are discussed in detail. Finally, experimental results are shown to verify the performance of the proposed converter.

A Family of Multilevel Passive Clamp Circuits With Coupled Inductor Suitable for Single-Phase Isolated Full-Bridge Boost PFC Converter

A family of multilevel passive clamp circuits is proposed and investigated in a single-phase isolated full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed effectively, and the absorbed energy can be transferred to the output side automatically. These clamp circuits are composed of several capacitors, diodes and one coupled inductor. With the help of the coupled inductor, synchronous resonances of the different resonant circuits can be achieved, which will avoid the unbalance of the voltage and current in these circuits. For the N-level passive clamp circuit, as N increases, the maximum duty cycle of the PFC converter will increase, the current stress of the switches will decrease, and the volume of the coupled inductor will decrease. Take a three-level clamp circuit for example, the operational principle of multilevel clamp circuits are discussed. Furthermore, some related analysis and comparison are given. Finally, experimental study has been done on a laboratory-made single-phase PFC prototype in which a four-level and a five-level clamp circuits are adopted, respectively. The feasibility of the proposed method and the validity of the theoretical analysis are verified by the experimental results.

A Simple Grid-Voltage-Sensorless Control Scheme for PFC Boost Converters

This paper introduces a simple grid-voltage-sensorless control scheme for single-phase power factor correction (PFC) boost converters. The grid voltage waveform is obtained based on the dc output voltage, the switching duty ratio, and a phase-lead compensator. In addition, the duty ratio feedback is utilized to obtain the unity input power factor and the zero harmonic current. The proposed control scheme is designed and mathematically analyzed based on a small-signal model of PFC boost converters. To verify the effectiveness of the proposed control scheme, several simulations and experiments are carried out in two applications: an industrial power system with a 60 Hz grid frequency and a commercial aircraft application with a 400 Hz grid frequency.

Improved passive snubbers suitable for single‐phase isolated full‐bridge boost power factor correction converter

In this study, two novel improved passive snubbers suitable for isolated full-bridge boost topology are proposed. The snubbers are composed of two capacitors, two inductors and four diodes. The voltage spike across the primary side of transformer is absorbed by one capacitor of the snubbers during a charging period, and by the other capacitor in the following charging period. The energy of capacitors can be transferred to the output side of the power factor correction (PFC) converter during one charging period by the resonance of the inductors and capacitors. Taking one improved snubber, for example the operational process of the original and the improved snubbers are analysed in a single-phase isolated full-bridge boost PFC converter. Furthermore, between the original and the improved snubbers, comparative analysis about the voltage and current stress, parameters limitation and the reliability are given. Finally, experimental study has been done on a laboratory-made single-phase PFC prototype, and the feasibility of the proposed method and the validity of the theoretical analysis are verified by the experimental results.

Analysis and Design of a New AC–DC Single-Stage Full-Bridge PWM Converter With Two Controllers

Single-phase power factor correction (PFC) ac-dc converters are widely used in the industry for ac-dc power conversion from single phase ac-mains to an isolated output dc voltage. Typically, for high-power applications, such converters use an ac-dc boost input converter followed by a dc-dc full-bridge converter. A new ac-dc single-stage high-power universal PFC ac input full-bridge, pulse-width modulated converter is proposed in this paper. The converter can operate with an excellent input power factor, continuous input and output currents, and a non-excessive intermediate dc bus voltage and has reduced number of semiconductor devices thus presenting a cost-effective novel solution for such applications. In this paper, the operation of the proposed converter is explained, a steady-state analysis of its operation is performed, and the results of the analysis are used to develop a procedure for its design. The operation of the proposed converter is confirmed with results obtained from an experimental prototype.

A Simple Implementation of Nonlinear-Carrier Control for Power Factor Correction Rectifier With Variable Slope Ramp on Field-Programmable Gate Array

This paper presents an algorithm for implementing the nonlinear-carrier (NLC) control method for a single-phase power factor correction (PFC) rectifier without an input voltage-sensing circuit, an error amplifier in the current shaping loop, or other external control components. Unity power factor and low harmonic distortion are achieved by adapting NLC control with a variable slope ramp. This ramp is created through a slope comparison without any dividers. The proposed method not only achieves a high power factor, but also efficiently simplifies complexity of integrated circuit realization. A 400-W PFC boost rectifier is implemented to verify the performance of the proposed NLC control. The highest power factor reaches to 99.9% with input voltage of 120 V/60 Hz, and the lowest input current harmonic distortion is 4.267%.

Multiobjective Optimization of Ultraflat Magnetic Components With PCB-Integrated Core

In future applications, e.g., in ultra-flat OLED lamp drivers or flat screen power supplies, ultra-flat ac/dc and dc/dc converter systems are highly demanded. Therefore, the design and implementation of a printed circuit board (PCB)-integrated flyback transformer for a 1-mm-thin single-phase power factor correction rectifier is under investigation. In this paper, first an overview on several integration methods is given. It is shown that the PCB integration of magnetic cores allows us to achieve the required thickness of 1 mm and a high energy density. In a next step, the design and the realization of ultra-flat magnetic components with PCB-integrated cores are discussed in detail. The presented multi-objective design procedure determines the inductor and/or transformer setup optimal with respect to minimal losses and/or minimal footprint area; for this purpose, all required electrical, magnetic, and geometrical parameters of the magnetic component are considered in the design process. Furthermore, all specific implications entailed by the PCB-integrated core, e.g., the core setup, anisotropic core losses, the interleaving of windings, or an accurate reluctance model are treated. Finally, experimental results are used to verify the design procedure.

Investigation and Implementation of a Passive Snubber with a Coupled-Inductor in a Single-Stage Full-Bridge Boost PFC Converter

In this paper, an improved passive snubber is investigated in a single-phase single-stage full-bridge boost power factor correction (PFC) converter, by which the voltage spike across primary side of the power transformer can be suppressed and the absorbed energy can be transferred to the output side. When compared with the basic passive snubber, the two single-inductors are replaced by a coupled-inductor in the improved snubber. As a result, synchronous resonances in the snubber can be achieved, which can avoid the unbalance of the voltage and current in the snubber. The operational principle of the improved passive snubber is analyzed in detail based on a single-phase PFC converter, and the design considerations of both the snubber and the coupled-inductor are given. Finally, a laboratory-made prototype is built, and the experimental results verify the feasibility of the proposed method and the validity of the theoretical analysis and design method.

A Novel Three-Phase Power Factor Correction with Digital Control

A new three-phase power-factor-correction (PFC) scheme is discussed using two single phase power factor correction circuit parallel connected. Two phase orthonormal voltage is produced by means of a auto transformer from a three phase input,fluctuation of neutral point by three single phase power-factor-correction circuit parallel connected is canceled,coupling interference is reduced among three phases,digitally controlled Power Factor Correction Boost Converters is adapted,input current wave sine with unity power factor suppress the secondary harmonic of input AC side is realized,voltage and low current stresses across each switch are reduced. Simulation and experimental results prove that it can achieve high power factor,low current,good capability of anti-interference and high reliability.

The Essence of Three-Phase PFC Rectifier Systems—Part I

In the first part of this paper, three-phase power factor correction (PFC) rectifier topologies with sinusoidal input currents and controlled output voltage are derived from known single-phase PFC rectifier systems and/or passive three-phase diode rectifiers. The systems are classified into hybrid and fully active pulsewidth modulation boost-type or buck-type rectifiers, and their functionality and basic control concepts are briefly described. This facilitates the understanding of the operating principle of three-phase PFC rectifiers starting from single-phase systems, and organizes and completes the knowledge base with a new hybrid three-phase buck-type PFC rectifier topology denominated as Swiss Rectifier. Finally, core topics of future research on three-phase PFC rectifier systems are discussed, such as the analysis of novel hybrid buck-type PFC rectifier topologies, the direct input current control of buck-type systems, and the multi-objective optimization of PFC rectifier systems. The second part of this paper is dedicated to a comparative evaluation of four rectifier systems offering a high potential for industrial applications based on simple and demonstrative performance metrics concerning the semiconductor stresses, the loading and volume of the main passive components, the differential mode and common mode electromagnetic interference noise level, and ultimately the achievable converter efficiency and power density. The results are substantiated with selected examples of hardware prototypes that are optimized for efficiency and/or power density.

A Flicker-Free Electrolytic Capacitor-Less AC–DC LED Driver

The electrolytic capacitor is the key component that limits the operating lifetime of LED drivers. If an ac–dc LED driver with power factor correction (PFC) control is allowed to output a pulsating current for driving the LEDs, the electrolytic capacitor will no longer be required. However, this pulsating current will introduce light flicker that varies at twice the power line frequency. In this paper, a configuration of flicker-free electrolytic capacitor-less single-phase ac–dc driver for LED lighting is proposed. The configuration comprises an electrolytic capacitor-less PFC converter and a bidirectional converter, which serves to absorb the ac component of the pulsating current of the PFC converter, leaving only a dc component to drive the LEDs. The output filter capacitor of the bidirectional converter is intentionally designed to have a large voltage ripple, thus its capacitance can be greatly reduced. Consequently, film capacitors can be used instead of electrolytic capacitors, leading to the realization of a flicker-free ac–dc LED driver that has a long lifetime. The proposed solution is generally applicable to all single-phase PFC converters. A prototype with 48-V, 0.7-A output is constructed and tested. Experimental results are presented to verify the effectiveness of the flick-free electrolytic capacitor-less ac–dc LED driver.

Analysis and Design of a Tapped-Inductor Buck–Boost PFC Rectifier With Low Bus Voltage

This paper presents a single-phase power factor corrector based on a tapped-inductor buck-boost converter. This paper suggests simplified models of the power stage under current-mode control and derives small-signal transfer functions of both the current and voltage control loops. Design rules for implementation of the proposed power factor corrector (PFC) are also suggested. The proposed PFC features low dc bus voltage, arbitrary lower than the peak line voltage. The proposed PFC is suitable for applications in computers and communications, where dc isolation can be provided by the downstream dc/dc converters. Simulation and experimental results are also reported and stand in good agreement with theoretical expectations.

Average Current Control of a Series-Type Single-Phase PFC With Hybrid Modulation

This letter proposes a hybrid modulation scheme for the average current control (ACC) of the series-type single-phase power factor correction (PFC). The series PFC is a newly developed harmonic correction method for single-phase diode rectifier. It is composed of a hybrid full-bridge inverter and is in cascade between the dc terminal of the diode rectifier and the dc load. When the conventional ACC is applied, due to the large duty-ratio variation at the low-frequency transition points, the line current waveforms exhibit large distortion at the low-frequency switching points. A hybrid scheme, which combines the leading-edge and the trailing-edge modulation, is developed to overcome this problem. The reference signal selection and control logic design are discussed and implemented. Experimental results show that the proposed hybrid approach is able to reduce the harmonic distortion in the line current significantly, as compared with the conventional ACC control.

Simulation and Experiment Study on Three-Phase PFC Rectifier Using MC33262

This paper introduces a single-phase power factor correction (PFC) rectifier using MC33262; explores and clarifies parallel three-phase PFC rectifier analyses and explanations; proposes an improving method; uses PSpice simulation software to make modeling, simulation and experiment for the improved three-phase PFC rectifier; and verifies its correctness and feasibility as well.

Fuzzy Controlled Parallel AC-DC Converter for PFC

Paralleling of converter modules is a well-known technique that is often used in medium-power applications to achieve the desired output power by using smaller size of high frequency transformers and inductors. In this paper, a parallel-connected single-phase PFC topology using flyback and forward converters is proposed to improve the output voltage regulation with simultaneous input power factor correction (PFC) and control. The goal of the control is to stabilize the output voltage of the converter against the load variations. The paper presents the derivation of fuzzy control rules for the dc/dc converter circuit and control algorithm for regulating the dc/dc converter. This paper presents a design example and circuit analysis for 200 W power supply. The proposed approach offers cost effective, compact and efficient AC/DC converter by the use of parallel power processing. MATLAB/SIMULINK is used for implementation and simulation results show the performance improvement.