Bridgeless Power Factor Correction Converter Research Articles

Efficiency and PF Improving Techniques with a Digital Control for Totem-Pole Bridgeless CRM Boost PFC Converters

A totem-pole bridgeless boost converter is one of the most promising topologies for the power factor correction (PFC) stage in high-power applications due to its high efficiency and small number of components. However, due to the totem-pole structure of the field-effect transistor (FET), very high switching loss occurs via the reverse recovery current of the body diode. To solve these problems, critical mode (CRM) control is a good solution to achieve the valley switching technique. With valley switching of CRM control, the switching loss decreases drastically with decreasing turn-on voltage. But, although the CRM control enables valley switching, it is hard to make an exact valley switching control with general zero-voltage detection circuits. In addition, when a frequency limitation scheme is applied to prevent a very high frequency, the switch can operate with hard switching at the boundary of the frequency limitation. Furthermore, the CRM boost PFC has a low PF and high total harmonic distortion (THD) under light-load conditions due to the large negative current resulting from resonance between the inductor and parasitic capacitance. It becomes worse at near-zero input voltage since the resonance current becomes larger near zero-input voltage. Therefore, in this paper, a totem-pole bridgeless boost PFC converter with high efficiency, high PF, and low THD is developed using TMS320F28377 by Texas Instruments. Based on the basic digital structure of the totem-pole bridgeless converter, the proposed controls help with exact valley switching, PF and THD improvement, and frequency limitation. The prototype converter is verified using 90–264 VAC input voltages and 450 V/3.3 kW output specifications.

Bridgeless PFC Converter without Electrolytic Capacitor Based on Power Decoupling

Due to fewer conduction devices in operating condition, the bridgeless power factor correction (PFC) converter is more efficient than the traditional PFC circuit. However, to achieve a low output voltage ripple on the DC side, a large electrolytic capacitor must be connected in parallel to the output end. To reduce the value of capacitance, this paper proposes a dual-boost bridgeless PFC converter with a bidirectional buck/boost power decoupling converter in the latter stage. The bidirectional converter absorbs double-line-frequency ripple, lowering the power pulsation at the output end while realizing power decoupling. The one-cycle control is adopted in bridgeless PFC converter, so that the input current can follow the input voltage to achieve power factor correction and decrease harmonic pollution. The power decoupling circuit is designed with a voltage outer loop using PI control and a current inner loop using model predictive current control, which alleviates the output voltage fluctuation caused by the reduction of the capacitance value of the filter capacitor, for the purpose of realizing non-electrolytic capacitor. Finally, the topology and control strategy involved in this paper are simulated and experimented to verify the validity and superiority of the theory.

High Efficiency Common Mode Coupled Inductor Bridgeless Power Factor Correction Converter With Improved Conducted EMI Noise

The conventional power factor correction (CPFC) converter suffers from excessive heat generation due to high conduction loss from the input bridge diode. Various bridgeless PFCs (BPFCs) have been proposed to overcome this drawback. Among them, the conventional BPFC (CBPFC) features the significantly reduced conduction loss but has very poor conducted electromagnetic interference (EMI) noise. Further, the semi-BPFC features the reduced input diode loss and good EMI, but the input diode loss is too significant to ignore. Although another solution, totem-pole BPFC, features high efficiency and good EMI, it usually requires expensive current sensors and microprocessor. A BPFC with the integrated magnetics common mode coupled inductor (ICC) is proposed to overcome the drawbacks of traditional BPFCs. The ICC can significantly reduce the system size by integrating three inductive components into a single magnetic core. Moreover, the small magnetizing current of the ICC, not the main input current, flows through input diodes; thus, experimental results from a 600 W rated prototype prove that the input diode loss can be significantly reduced by about 10 W compared to the CPFC, and the input diode exhibits a low heat generation of 49.8 °C despite the absence of a heat sink. In particular, with the help of input diodes, the EMI noise spectra of the ICC BPFC can meet the EMI standard with a sufficient margin. The detailed analysis, design guide and experimental results from a 600 W rated prototype are provided to confirm the validity of the ICC BPFC.

Research on the Control Strategy of dual Boost bridgeless PFC based on Lyapunov stability

In order to prevent power electronic devices from causing harmonic pollution to the power grid, PFC technology is widely used between power electronic devices and the power grid. Therefore, the improvement of system power factor and robust performance has become a research focus today. This paper is aimed at dual Boost bridgeless PFC (power factor correction) converters, establishes a mathematical model in virtual dq mode, and a new nonlinear control strategy based on Lyapunov stability is proposed. The MATLAB simulation results show that the input current can better track the input voltage in the steady state, and when the load or output voltage changes, the system can quickly enter stability, and the system has strong anti-disturbance ability.

A Novel Bridgeless Cuk PFC Converter With Further Reduced Conduction Losses and Simple Circuit Structure

The bridgeless power factor correction (PFC) converter is popular for reducing the conduction losses of semiconductors. In this article, a novel bridgeless Cuk PFC converter is proposed. Compared with the conventional Cuk PFC converter, the number of conducting semiconductors in the proposed bridgeless Cuk PFC converter is reduced, contributing to lower conduction losses. Moreover, the conduction losses in the proposed converter are further improved compared with the pseudototem-pole bridgeless Cuk PFC converter. Meanwhile, the total number of the component in the proposed converter is less than other bridgeless Cuk PFC counterparts, especially for the big-volume magnetic component and electrolytic capacitor. In addition, all power switches in the proposed converter are common ground and can be driven by one control signal, availing simple drivers. The theoretical analysis of the proposed converter is presented in the discontinuous conduction mode with the merits of nature current-sharping ability, zero-current switching in semiconductors, and easy control. Finally, the simulation and a 100-W lab prototype are built to validate the feasibility of the proposed bridgeless Cuk PFC converter.

A Reconfigurable Totem-Pole PFC Rectifier With Light Load Optimization Control Strategy and Soft-Switching Capability

This article presents a reconfigurable totem-pole bridgeless power factor correction converter employing an auxiliary circuit and a simple control scheme to achieve high efficiency. Under light load condition, instead of delivering the energy through the main switch, the proposed converter utilizes only the auxiliary switches by using a different control scheme. Since the auxiliary switches have much smaller parasitic capacitances than the main switches, the proposed converter can obtain high efficiency under light load condition. Over middle-to-heavy load condition, the proposed converter can acquire both zero-voltage switching operation and relieved reverse-recovery problem thanks to the auxiliary circuit, which leads to high efficiency even with Si-MOSFET in the continuous conduction mode control. As a result, the proposed converter can achieve high efficiency over the entire load condition. The effectiveness of the proposed converter is verified by a prototype with ac 230Vrms input and 750 W output.

Extended Range Bridgeless PFC Converter With High-Voltage DC Bus and Small Inductor

Utility power lines voltage levels vary in different geographical locations, ranging from 208 to 480 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> . Power factor correction (PFC) converters are typically designed for a particular input voltage and do not accept a wide range of line voltages. This results in multiple product designs and revisions and increased production costs to accommodate the various ac voltage levels used around the world. A PFC converter capable of coping with a wide input voltage range, from 90 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> up to 530 V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> , would significantly decrease costs and streamline development. In this article, an extended input voltage range PFC converter is proposed, which provides a high and almost flat efficiency curve throughout the entire operating voltage range with an 800 VDC bus voltage. The proposed converter has a flexible bridgeless structure with simple control, low-current ripples, low common mode noise, and startup inrush current handling capabilities. Theoretical analysis and waveforms are discussed and experimental results for a 2-kW prototype are given, thereby validating the expected behavior. The operation of the proposed extended input voltage range PFC converter is also compared to the traditional totem-pole PFC showing more than 1% efficiency improvements at full load and a higher power factor in the proposed design.

New Bridgeless Power Factor Correction Converter With Simple Gate Driving Circuit and High Efficiency for Server Power Applications

A bidirectional-switch bridgeless power factor correction (PFC) converter (BBPFC) is a fascinating topology for high-power application among various bridgeless PFC (BPFC) converters due to its simple structure and easy control method despite using a floating gate driver. In addition, by varying reverse recovery characteristics of rectifying diodes placed on the conduction path, it is possible to improve common-mode (CM) noise characteristics without additional line filter. However, the BBPFC is difficult to actually use in server power supply product because of high guarantee payment. Thus, in this article, a new BPFC for high efficiency and simple structure without any patent issues is proposed. Moreover, it can be simply implemented since the proposed converter does not require floating gate driver but use a simple bootstrap circuit. Furthermore, in both positive and negative cycles, the proposed converter can have lower power loss characteristics due to utilization of one switch for build-up operation. The proposed converter also uses the relative reverse recovery characteristics resulting in good CM noise characteristics. Thus, the proposed converter can obtain high efficiency and good CM noise characteristics with simple structure and easier control method. The effectiveness of the proposed converter is verified by a prototype in universal input and 800-W/400-V output.

DSP‐based comparison of PFC control techniques applied on bridgeless converter

A comparison of fuzzy self-tuning (FST), sliding mode control (SMC) and conventional proportional-integral (PI) control methods is performed under unbalanced grid conditions using a bridgeless power factor correction (PFC) converter. The bridgeless PFC converter operates the correction of AC line current to obtain a DC output voltage without full bridge rectifier based on these control methods. These control methods generate the duty cycles to provide higher unity power factor and lower total harmonic distortion of input current, even if AC line voltage is distorted. This study focuses on the performance analysis of FST and SMC methods adaptation to the input current for the bridgeless PFC converter and comparing with the conventional PI controller. Although the SMC method is only used in the current control loop, the FST method is used in both current and voltage control loops for eliminating harmonics of input current and regulating of output voltage. The performance of control methods is evaluated with a TMS320F2812 digital signal processor. The simulation and experimental results are compatible with the limits for harmonic current emissions, IEC 61000-3-2 and show that the FST and SMC are better than the conventional PI control method and FST is superior to the SMC.

Resonant Bridgeless AC/DC Rectifier With High Switching Frequency and Inherent PFC Capability

Boost-based converters are used in a variety of non-isolated step-up applications, such as power factor correctors, because of their simplicity. The power density of these converters can be increased in higher switching frequencies, which reduces the size of the magnetic elements. This increases the switching losses, but that can be solved by soft-switching techniques. This paper proposes a resonant bridgeless power factor correction converter that provides soft switching for all of the semiconductors. The proposed structure can provide zero voltage switching for the switches and zero current switching for the diodes. In the proposed structure, the input current is inherently sinusoidal with low total harmonic distortion, even with small inductances. Therefore, a high input power factor is achieved without requiring a current control loop in the circuit. This reduces the complexity of the control circuit. An experimental prototype has been constructed to investigate the validity of the claims. Experimental results show near-unity power factor, as well as $\text{2}\%$ efficiency improvement at full load when compared to a conventional interleaved boost converter with the same components.

A New Bridgeless High Step-up Voltage Gain PFC Converter with Reduced Conduction Losses and Low Voltage Stress

Bridgeless power factor correction (PFC) converters have a reduced number of semiconductors in the current flowing path, contributing to low conduction losses. In this paper, a new bridgeless high step-up voltage gain PFC converter is proposed, analyzed and validated for high voltage applications. Compared to its conventional counterpart, the input rectifier bridge in the proposed bridgeless PFC converter is completely eliminated. As a result, its conduction losses are reduced. Also, the current flowing through the power switches in the proposed bridgeless PFC converter is only half of the current flowing through the rectifier diodes in its conventional counterpart, therefore, the conduction losses can be further improved. Moreover, in the proposed bridgeless PFC converter, not only the voltage stress of power switches is lower than the output voltage, but the voltage stress of the output diodes is lower than the conventional counterpart. In addition, this proposed bridgeless PFC converter features a simple circuit structure and high PFC performance. Finally, the proposed bridgeless PFC converter is analyzed and designed in the discontinuous conduction mode (DCM). The simulation results are presented to verify the effectiveness of the proposed bridgeless PFC converter.

New Bridgeless Buck PFC Converter with Improved Input Current and Power Factor

The bridgeless buck power factor correction (PFC) converters feature the merits of low output voltage and high efficiency while their inherent dead angles in the input current will deteriorate the input current harmonics and power factor (PF). Aiming to reduce the dead angles, a new bridgeless buck PFC converter is proposed in this paper. Through integrating the main buck circuit and the auxiliary flyback circuit with one magnetic core, the dead angles in the input current of the proposed bridgeless buck PFC converter is eliminated so that the PF and input current harmonics are improved. The proposed bridgeless buck PFC converter is designed to operate in discontinuous conduction mode (DCM) with the merits of simple controller and nature current shaping ability. A new logic control circuit is provided. The detailed theoretical derivations and design consideration are presented. The experimental comparison among the proposed bridgeless buck PFC converter, the conventional buck PFC converter, and the conventional bridgeless buck PFC converter is displayed to validate the effectiveness of the new converter.

AC–DC bridgeless buck converter with high PFC performance by inherently reduced dead zones

In this study, a novel AC-DC bridgeless buck converter for power-factor-correction (PFC) applications with the inherent current-shaping ability and high PFC performance is proposed. Under a certain operation condition, dead zones in the proposed converter are reduced inherently compared with its conventional buck PFC counterpart, which result in higher PF and lower total harmonic distortion significantly. Furthermore, two rectifier diodes are eliminated, which contributes to efficiency. The detailed operation principle and theoretical analysis of discontinuous conduction mode (DCM) are presented. The simulation comparison between the conventional and proposed bridgeless buck PFC converter is also described. Finally, an experimental lab-made prototype operating in DCM is constructed to validate the feasibility of this proposed converter.

Single-Stage Bridgeless LED Driver Based on a CLCL Resonant Converter

This paper presents a single-stage light-emitting diode (LED) driver based on a bridgeless power factor correction (PFC) converter and a half-bridge CLCL resonant converter for street lighting applications. The proposed single-stage topology integrates the PFC converter and the CLCL resonant converter by sharing active power switches. The bridgeless PFC converter adopts two buck–boost circuits operating in discontinuous-conduction mode to achieve input-current shaping. It uses two diodes instead of a rectifier bridge to reduce the power loss caused by the diodes. Owing to its superior soft-switching characteristics, the CLCL resonant converter is used. The proposed LED driver has superior features, such as high efficiency, near unity power factor, low total harmonic distortion, and relatively few diodes. A 100-W lab prototype is successfully implemented, and the experimental results verify the effectiveness and feasibility of the proposed LED driver.

Efficient bridgeless PFC converter with reduced voltage stress

SummaryAn efficient bridgeless power factor correction converter with reduced voltage stress is proposed. In the proposed converter, the input full‐bridge rectifier is removed to reduce the conduction loss of rectification, and the voltage stress of switching devices is significantly reduced by utilizing the additional circuit composed of a capacitor and a diode. Therefore, low‐voltage‐rating diodes with less forward voltage drop and low‐voltage‐rating Metal‐Oxide‐Semiconductor Field‐Effect Transistor (MOSFET) with low RDS(on) is utilized. The proposed converter is based on the single‐ended primary‐inductor converter power factor correction operation in discontinuous conduction mode to achieve a high power factor with a simple control circuit. Consequently, the proposed converter can provide a high power factor and a high power efficiency, and it is also suitable for low‐cost converter for high input/output voltage system. The operational principles, steady‐state analysis, and design equations of the proposed converter are described in detail. Experimental results are verified for a 130 W prototype at a constant switching frequency 100 kHz. Copyright © 2015 John Wiley &amp; Sons, Ltd.

Study on a Novel High-Efficiency Bridgeless PFC Converter

In order to implement a high-efficiency bridgeless power factor correction converter, a new topology and operation principles of continuous conduction mode (CCM) and DC steady-state character of the converter are analyzed, which show that the converter not only has bipolar-gain characteristic but also has the same characteristic as the traditional Boost converter, while the voltage transfer ratio is not related with the resonant branch parameters and switching frequency. Based on the above topology, a novel bridgeless Bipolar-Gain Pseudo-Boost PFC converter is proposed. With this converter, the diode rectifier bridge of traditional AC-DC converter is eliminated, and zero-current switching of fast recovery diode is achieved. Thus, the efficiency is improved. Next, we also propose the one-cycle control policy of this converter. Finally, experiments are provided to verify the accuracy and feasibility of the proposed converter.

Analysis of the Admittance Component for Digitally Controlled Single-Phase Bridgeless PFC Converter

This paper analyzes the effect of the admittance component for the digitally controlled single-phase bridgeless power factor correction (PFC) converter. To do this, it is shown how the digital delay effects such as the digital pulse-width modulation (DPWM) and the computation delays restrict the bandwidth of the converter. After that, the admittance effect of the entire digital control system is analyzed when the bridgeless PFC converter which has the limited bandwidth is connected to the grid. From this, the waveform distortion of the input current is explained and the compensation method for the admittance component is suggested to improve the quality of the input current. Both the simulations and the experiments are performed to verify the analyses taken in this paper for the 1 kW bridgeless PFC converter prototype.

Digital Plug-In Repetitive Controller for Single-Phase Bridgeless PFC Converters

This paper investigates a plug-in repetitive control scheme for bridgeless power factor correction (PFC) converters to mitigate input current distortions under continuous conduction mode and discontinuous conduction mode operating conditions. From the PFC converter model and the fact that a type-II compensator is used, a design methodology to maximize the bandwidth of the feedback controller is suggested. After that, the error transfer function including the feedback controller is derived, and the stability of the repetitive control scheme is evaluated using the error transfer function. The implementation of the digital repetitive controller is also discussed. The simulation and experimental results show that the input current THD is significantly improved by using the proposed control scheme for a 1-kW single-phase bridgeless PFC converter prototype.

Common Mode EMI Noise Suppression for Bridgeless PFC Converters

The goal of this paper is to study the possibility of minimizing common mode (CM) noise emission in bridgeless power factor correction (PFC) converters. Two approaches are proposed. In the first approach, the bridgeless PFC is modified to achieve symmetry. A CM noise model for symmetric topology is derived and the conditions for symmetry are summarized. Parasitics critical to the symmetrical condition are studied and carefully controlled. As a result, CM noise can be minimized with good cancellation. The second approach is to introduce a balance technique to bridgeless PFC converters. The topology is modified so that the balance technique can be applied so as to minimize CM noise. Experimental results validate that both approaches can greatly reduce CM noise up to 30 dBmuV. The two approaches are compared in terms of both its effects on CM noise and their implementations.