Buck-boost Power Factor Correction Research Articles

High-Efficiency ZVS AC-DC LED Driver Using a Self-Driven Synchronous Rectifier

This paper proposes a high-efficiency zero-voltage-switching (ZVS) AC-DC light-emitting-diode (LED) driver. The structure of the proposed converter is based on a buck-boost power-factor-correction (PFC) converter. Through replacement of an output diode with a self-driven synchronous rectifier (SR), the conduction loss decreases significantly, and there is no switching loss because of the ZVS operation of the switching devices. In addition, no additional control circuit is required and cost reduction is achieved because the SR is self-driven. The efficiency of the proposed converter is higher than that of the conventional critical-conduction-mode (CRM) buck-boost PFC converter, owing to the reduced conduction loss of the high-side output rectifier and no switching loss of either of the switches. For verifying the ZVS operation and efficiency improvement of the proposed AC-DC LED driver, theoretical analysis and experimental results of a 48-[V] and 1.4-[A] prototype for LED driver are discussed.

An Off-line Battery Charger based on Buck-boost Power Factor Correction Converter for Plug-in Electric Vehicles

This paper presents an off-line battery charger based on the buck-boost power factor correction (PFC) converter for plug-in electric vehicles (EV). The integrated battery charger is obtained from the traditional three-phase voltage source inverter (VSI) for EV, which operates as buck-boost converter with power factor correction ability. The PFC controller is regulates the battery voltage and controls the supply current of the converter to achieve unity power factor which is very simple and gives good performance. The proposed buck-boost PFC converter is operating in buck mode and boost mode, which is alternatively carried out according to the relationship between the rectified input voltage and battery voltage. The practicality and performance of the battery charger of the proposed converter topology has been verified via simulation.

High‐efficiency two‐switch tri‐state buck–boost power factor correction converter with fast dynamic response and low‐inductor current ripple

Two-switch tri-state buck-boost power factor correction (PFC) converter operating in pseudo-continuous conduction mode is proposed and analysed in this study. Different from tri-state boost PFC converter, the proposed two-switch tri-state buck-boost PFC converter does not need additional power switch to provide the additional degree of control freedom. Therefore it does not increase the complexity and affect the power conversion efficiency of the PFC converter as in the case of tri-state boost PFC converter. For the proposed two-switch tri-state buck-boost PFC converter, the current control loop and voltage control loop are decoupled, a simple voltage control loop with faster dynamic response can be designed to realise output voltage regulation and the additional degree of control freedom introduced by inductor current freewheeling stage helps to achieve unity power factor control. The operation principle, the input current, the inductor current ripple, the switch component stress and the small-signal characteristics of the proposed two-switch tri-state buck-boost PFC converter are analysed. The simulation and experimental results show that the proposed two-switch tri-state buck-boost PFC converter benefits with fast dynamic response, high-efficiency and low-inductor current ripple over single-switch buck-boost PFC converter or two-switch buck-boost PFC converter operating in continuous conduction mode and discontinuous conduction mode.

Single-stage driver for supplying high-power light-emitting-diodes with universal utility-line input voltages

The conventional two-stage non-isolated driver for high-power light-emitting diodes (LEDs) is composed of a power-factor-correction (PFC) converter with a non-isolated flyback converter for regulating the output voltage/current for supplying LEDs. However, large numbers of circuit components are required and the total efficiency is limited because of two-stage power conversion. This study proposes a high-power LEDs driver based on a single-stage topology. The presented driver combines a buck-boost PFC converter with a non-isolated flyback converter with two output windings connected in series into a single-stage power-conversion circuit. The proposed driver offers high power factor, high efficiency, low total-harmonics-distortion (THD) of input utility-line current, cost-effectiveness and a constant-output voltage along with limited-output-current control scheme. Finally, a prototype driver is developed and tested in order to supply a 100 W LED light bar module with universal utility-line input voltages for indoor or outdoor general lighting applications. Operational analysis, design equations, a design example and experimental results provided by examining three LED light bar modules demonstrate the feasibility of the proposed circuit.

Novel Single-Stage Self-Oscillating Dimmable Electronic Ballast With High Power Factor Correction

A novel self-oscillating electronic ballast with dimming capability and high power factor correction (PFC) is proposed in this paper. The single-stage electronic ballast integrates a buck-boost PFC stage with a half-bridge LCC series-parallel resonant inverter. The buck-boost semistage operating in discontinuous conduction mode inherently has high PFC. The inverter is dimmable in self-oscillation mode, which is achieved using pulsewidth modulation and variable-frequency controls. The dimming circuit is simple and low cost. The self-sustained oscillation of the dimmable electronic ballast for fluorescent lamps was verified using the dual-input describing function method. A prototype of a 10-W dimmable electronic ballast was implemented to verify the theoretical analysis.

A Dimmable Electronic Ballast With Unity Power Factor Based on a Single-Stage Current-Fed Resonant Inverter

A single-stage dimmable electronic ballast with very high power factor and high efficiency is presented in this paper. A compact lamp power circuit is designed by integrating a buck-boost power factor corrector with a current-fed resonant inverter. This integration produces a single power-processing unit that minimizes the number of circuit components. The proposed resonant inverter reduces the circulating current in the resonant tank and allows simple gate drivers to be used so that isolation devices can be eliminated. With the buck-boost stage operating in the discontinuous conduction mode (DCM), a close-to-unity power factor is achieved for different lamp-power conditions. A small-signal analysis is presented, and a simple variable frequency controller is developed using the modified 555 timer to provide dimming operations. Simulation and experimental waveforms are provided to highlight the merits of the proposed circuit for a 40-W compact fluorescent lamp.

PWM Technique for Non-Isolated Three-Phase Buck-Boost PFC Converter

The buck-boost power factor corrected (PFC) converter has the wide range of the dc output voltage. A new non-isolated three-phase hard-switching and a soft-switching buck-boost PFC converter are proposed. Removing the three-phase transformer from the converters makes their size more compact and their costs lower. In addition, the new control method based on the PWM technique is proposed in this paper to achieve the high power factor. Complete soft-switching is also achieved under the discontinuous current mode (DCM) operation.

Single-Stage Single-Switch High-Power-Factor Electronic Ballast for Fluorescent Lamps

This paper presents an efficient, small-sized, and cost-effective single-switch power-factor-correction (PFC) scheme for high-frequency electronic ballasts. The circuit topology originates from the integration of a buck-boost PFC converter and class-E electronic ballast. Only one active power switch is commonly used by both power stages to save the cost of active switches and control circuits. The active switch is controlled by pulsewidth modulation at a fixed switching frequency and constant duty cycle. The electronic ballast can achieve nearly unity power factor by operating the buck-boost converter at discontinuous conduction mode. With carefully designed circuit parameters, the active power switch can be operated at zero-voltage switching, leading to high circuit efficiency. A prototype circuit designed for a PL-27-W compact fluorescent lamp is built and tested to verify the theoretical predictions. Satisfactory performance is obtained from the experimental results.

Current programmed control of a single-phase two-switch buck-boost power factor correction circuit

This paper presents a new current programmed control (CPC) technique for a cascaded two-switch buck-boost converter suitable as a low-cost power factor correction (PFC) rectifier in a variable speed motor drive. This new CPC technique, which is an extension of the conventional CPC method, enables the variable output dc voltage, and is therefore suitable in a pulse amplitude modulated (PAM) motor drive or as a universal input-power supply. The CPC method is very simple and requires only a constant-current reference without any changes in the transition between boost and buck operating mode, and the line current is practically unaffected by the topology-mode shift. Simulations and experimental results verify the presented control technique. Compliance with IEC-61000-3-2 class A is achieved. The experimental setup is based on a commercial CPC integrated circuit (IC) for dc-dc converters. This new control technique enables a simple low-cost control circuit for the two-switch buck-boost converter, which complies with IEC-61000-3-2, and the PFC circuit has inherent in-rush and overcurrent protection.

A single-phase buck-boost PFC converter with output-voltage, ripple-reducing operation

This paper describes a new single-phase buck-boost power-factor-correction (PFC) converter with output-voltage, ripple reducing operation. The converter consists of a conventional buck-boost PFC converter and an additional switch to obtain a freewheeling mode of the dc inductor current, and is operated by two modulators. The first modulator controls the buck-boost switch to obtain PFC. The other modulator controls the square value of the instantaneous dc inductor current to perform the output-voltage-ripple-reducing operation. In the two modulations, the time integral value of the input and output currents in each modulation period are controlled directly and indirectly, respectively. Thus, modulation errors or undesirable distortions of the input current and output voltage ripple are eliminated even if the dc inductor current produces large ripple in a low-frequency range. The theories and combination techniques for the two modulators, implementation, and experimental results are described. © 1998 Scripta Technica, Electr Eng Jpn, 126(2): 56–70, 1999

A Single-Phase Buck-Boost PFC Converter woth Output-Voltage-Ripple-Reducing Operation

This paper describes a new single-phase buck-boost Power-Factor-Correction (PFC) converter with outputvoltage-ripple-reducing operation. The converter consists of a conventional buck-boost PFC converter and an additional switch to obtain a freewheeling mode of the dc-inductor current, and is operated by two modulators. The first modulator controls the buck-boost switch to obtain PFC. The other modulator controls square-value of the instantaneous-dc-inductor-current to perform the output-voltage-ripple-reducing operation. In the two modulations, the time-integral-value of the input and output currents in each modulation period are controlled directly and indirectly, respectively. Thus, modulation errors or undesirable distortions of the input-current and output-voltage-ripple are eliminated even if the dcinductor-current produces large ripples in a low frequency range. The theories and combination techniques for the two modulators, implementation and experimental results are described.