Flyback Converter Research Articles

Single Stage Active Power Factor Correction Circuit for Street LED Light with Battery Backup

This paper proposes a single-stage active power factor correction circuit for street LED light with battery back-up. The buck–boost converter and flyback converter are combined to achieve optimal performance. The first part of the integrated LED driver, the buck–boost converter is used to adjust the power while operating in the discontinuous conduction operation. The second part of the driver, the flyback converter provides regulated voltage to the LEDs. The battery backup circuit charges the battery when ac input power is available and provides power to LED lamp when input power supply is not available. The proposed LED driver was designed for 100 W output power and tested by PSpice simulation. The simulation results obtained are given in the paper to demonstrates the functionality of the proposed LED driver system. The result show good operation and performance of proposed LED driver.

Quantitative analysis of common‐mode current in flyback converter with balance winding

AbstractThe balance winding of the transformer is a compact and flexible technique for the common‐mode (CM) noise reduction of isolated power converters. A proper design of the grounding and turn number of the balance winding will generate an inverse displacement current to balance the CM noise flowing through the transformer. However, a trial and error process to find the optimum design is necessary for practical applications due to the unexplored source of calculation errors. In this paper, a quantitative analysis method of CM currents flowing through all the paths between windings is proposed for error quantifications. Based on an interleaved transformer, the capacitances are extracted with the help of electric field simulations, and the contribution of each path to the CM noise is analysed. Although the paths between adjacent layers are dominant in the CM noise, it is proved that ignoring non‐adjacent inter‐layer paths will lead to calculation errors due to the high voltage difference even with low capacitances. As both the application and verification of the proposed quantitative analysis method, the accurate evaluation of noise reduction effects and determination of the optimum balance winding turns can be achieved in experiments.

Optimal Design of High Frequency Transformer for High Power Density Flyback Converter

This brief presents an optimal design of high power frequency transformer for flyback converter based on E-mode GaN device, which could be used in personal portable chargers. The new generation of wide band gap semiconductor GaN switch is used to improve the switching frequency of the circuit. The high-frequency magnetic core and the winding method of magnetic components are optimized. The leakage inductance of the transformer of magnetic components is greatly reduced. Consequently, the overall power density of the circuit is improved. The feasibility of the design scheme is verified by hardware implementation and experimental results. The test results show that compared with the traditional flyback magnetic element design, the volume of magnetic element is reduced by 30%. Meanwhile, the loss is reduced by 30%, and the peak efficiency of the converter can reach 94.2%. The ratio of leakage inductance of magnetic transformer to excitation inductance decreased from 2.2% to 1%. In addition, power density of the converter reached 20.26W/in3, which is much higher than the existing commercial ones.

A High-precision Digital Measurement System Design based on PSR

In engineering practice, a constant voltage output control system of synchronous rectifier primary side regulator (PSR) flyback converter is proposed to overcome the sampling defect of the existing digital approximation double line sampling scheme for primary side control synchronous rectifier structure. Regardless of the slope of the sampling waveform and the knee point, the single-output DAC midpoint sampling can achieve high sampling accuracy and good knee point following effect. At the same time, the neutral-point sampling error of the single-output DAC is analyzed, and a sampling compensation scheme which can simultaneously act in continuous current mode (CCM) and discontinuous current mode (DCM) is designed to further correct the sampling voltage obtained by neutral-point sampling, so as to compensate the voltage error of neutral-point sampling. Thus, the output voltage can be accurately constant in DCM and CCM.

A Secondary-Resonance MHz Active-Clamp Flyback Converter With Partial Power Processing

A 1 MHz active-clamp flyback converter for solar street-lighting applications, featuring a partial power processing, is proposed in this article. The secondary-side resonance between the output capacitor and transformer leakage inductor is utilized to reduce rms current and conduction losses. In comparison with the traditional light-emitting diode drivers based on full power converters (FPCs), the proposed approach that uses partial power converters (PPCs) can significantly improve the overall system efficiency by eliminating the redundant power handling process. The universal schemes are discussed and the optimal solution is eventually determined by the partial power ratio. The advantages of PPC compared with FPC in device stress, losses, and regulation capability are demonstrated by simulation. With GaN devices, a 100 W/1 MHz prototype was built to verify the analysis. The experimental results show that the proposed topology can reduce the power rating of the converter by up to about 80% while increasing the system efficiency by up to 95.8%.

A Unified Modeling Approach to Tapped Inductor Converters Accounting for the Leakage Inductance Effects

This article suggests a unified modeling approach to the analysis of tapped-inductor converters. The leakage inductance, inherent to coupled magnetic structures, and the associated snubber circuit effects were considered and incorporated into the suggested model. The proposed nonideal tapped inductor switcher model is formulated as an equivalent subgraph that can help to model most, if not all, converter topologies that comprise a two-winding tapped inductor. Both the continuous current mode and the discontinuous current mode were modeled. To validate the proposed approach, analysis of a Flyback converter with an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">RC</i> snubber is presented. Theoretical prediction of the steady-state and small-signal behavior of the converters were confirmed by simulation and experimental results.

Modified PWM Scheme to Reduce Reverse Conduction Loss in GaN-Based Independently Controlled Multiple Output Flyback Converter

The recently proposed independently controlled multiple output flyback converter (ICMOFC) scheme improves cross-regulation by utilizing gallium nitride (GaN) switches with negative gate turn- <sc xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">off</small> voltage. The highly inefficient reverse conduction (RC) of negative gate biased GaN devices leads to significant RC loss in the existing ICMOFC scheme. To mitigate this problem, this letter proposes a new pulsewidth modulation (PWM) scheme. The RC loss reduction is achieved by reducing the RC duration and RC current. The effectiveness of the proposed PWM strategy is analytically and experimentally verified using a 40-W dual output flyback converter. The results demonstrate a peak efficiency improvement of 1.26% over the existing ICMOFC scheme. Furthermore, the scheme also achieves high power density (51 W/in <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$^{3}$</tex-math></inline-formula> ) and excellent cross-regulation (0.2%).

Analysis of Various Topologies and Control Circuit used in Single Phase EV Charger

Abstract: In remote electric vehicle charging frameworks utilizing inductive power transfer (IPT), power electronic converters assume a basic part in decreasing size and cost, as well as boosting the proficiency of the whole framework. As of late, analysts have led huge examination studies to work on the exhibition of power transformation frameworks, including power converter topologies and control plans. Incorporated On-Board Battery Chargers (OBC) have been acquainted as ideal arrangement with increase of electric vehicle (EV) market penetration and limit the general expense of EVs. OBCs are by and large arranged into triphasic and monophasic types with unidirectional or bidirectional power stream. Existing electric vehicle (EV) chargers utilize a hard-core non-linear diode bridge-rectifier (BR) to exploit the DC volt at the contribution of the DC converter and acquaint quality of the power is a counted as a problem with the AC input. These problems insist improvement in Power Quality for existing battery charger for this purpose the bridgeless Cuk Converter is used with the flyback converter. Cuk Converter used single diode and switch and provide additional advantage like reduction in the switch volt-stress and higher efficiency equated to the other conventional bridgeless (BL) converters. Similarly, bridgeless isolated Zeta-Luo converter with PF correction is also used. The Zeta and Luo is functioned for the half cycle of the supply individually and give the benefits of the both topologies. In this paper BL Zeta, BL Cuk, BL Buck-Boost, BL Luo, BL Single Ended Primary Inductance Converter (BL SPIC), and Canonical Switched Cell (CSC) converters are reviewed.

Analysis of three phase AC-DC Flyback converter

Analysis of three phase AC-DC Flyback converter

A simple and highly efficient flyback inverter control strategy for AC module application

A simple and efficient control structure of a flyback converter is proposed in this paper considering its intrinsic dynamic characteristics. The proposed control strategy makes use of a PI controller with a low pass filter to overcome the limitations on determining the gains of the feedback control system result from the right-half-plane (RHP) zero and LC filter dynamics. Therefore, the target output current is properly tracked and the disturbances are attenuated by the proposed control system. Furthermore, the stability requirements are satisfied and a zero steady-state error is obtained by appropriately regulating the control signal. This control method is very fast applying the minimum number of delays in its scheme which causes the computational burden to be significantly reduced. Finally, the theoretical claims are confirmed by simulation and experimental results on a 200-W laboratory prototype.

An Enhanced Modified Multiport Interleaved Flyback Converter for Photovoltaic-Shunt Active Power Filter (PV-SHAPF) Applications

This paper presents a newly designed modified multiport interleaved flyback converter (MMPIFC) to transfer the photovoltaic (PV) power to the DC bus of the parallel-connected multilevel inverter-based shunt active power filter (SHAPF). The proposed modified multiport interleaved flyback converter (MMPIFC) is designed to interconnect N number of input power sources into the DC bus of the SHAPF to fix the problems with the partial shadow and improve the SHAPF’s ability to compensate. Compared to the commonly used interleaved flyback converter (IFC), the proposed MMPIFC has a larger boost factor toward the DC voltage input. The flow of power between the different power sources and SHAPF is controlled by varying the duty ratio of the main switches. The working principles of the proposed MMPIFC-operated PV-SHAPF are explored in this paper, and essential design concerns are highlighted. A prototype model with 1 kVA, 400 V, and 50 HZ is built and tested under various conditions to validate the theoretical analysis, design, and control method.

A Digital Adaptive Control Method for Optimizing Valley Current of Active Clamp Flyback Converter

In an active clamp flyback (ACF) converter working in critical mode (CRM), the zero-voltage switching (ZVS) of the main power switch can be realized by the negative valley current, which is related to conduction loss and switching loss. Therefore, how to control the negative valley current will affect the overall efficiency of the system. This article investigates and compares the three existing technologies and summarizes their limitations in practical applications. Therefore, a digital adaptive control method is proposed to regulate the valley current according to different working conditions. Meanwhile, small-signal analysis is performed to ensure the stability of the proposed control method. The proposed control method is verified by a field-programmable gate array (FPGA)-based 12-V, 3-A ACF, and experimental results show that the proposed theoretical model should be accurate and practical and there is an average efficiency improvement of 1.34% compared to conventional control.

Multi-layer state of health balancing control for a battery-based energy storage system to extend cycle life based on active equalization circuits

State of health (SoH) imbalance causes capacity waste and cycle life reduction of the battery-based energy storage systems (BESS), which demands SoH balancing control of the parallel-connected packs and the series-connected cells of the BESS. This study proposed a multi-layer SoH balancing control to extend the cycle life of the BESS. For the series-connected battery cells, active equalization circuits based on the fly-back converter are used to exchange energy between cells and control the depth of discharge (DoD) of cells to achieve the SoH balance. For the parallel-connected packs, SoH is equalized by distributing the output power based on the SoH balancing principle and the minimum power distribution constraints of packs caused by the bidirectional balancing current among the series-connected cells are considered. Because the proposed method achieves the SoH balancing by utilizing the active equalization circuits to transfer the energy between the cells with different SoH, it can achieve higher capacity and energy utilization efficiency and lower heat release compared with the passive equalization typology that dissipates the energy. The effectiveness of the proposed method is verified by a case study based on a 3-packs-15-cells BESS. Simulation results show that this method can prolong the cycle life of BESS by about 52.9% compared with the active SoC balancing method using the same fly-back converter and 18.3% with a passive multi-layer SoH balancing method, respectively.

An Active Clamp Flyback Converter With High Precision Primary-Side Regulation Strategy

The active clamp flyback (ACF) converter has been widely adopted because of the feature of isolation, soft-switching, and high conversion efficiency. On the other hand, due to the characteristic of the circuit cost reduction and the fast control response, the primary-side regulation (PSR) has become a popular control method for isolated power converters. However, high precision PSR strategies for ACF converters are not exposed. Therefore, the aim of this article is to propose a high precision PSR strategy for the ACF converter. Relations between the primary-side current and the secondary-side current are analyzed and derived. Both of the continuous conduction mode operation and the discontinuous conduction mode operation will be considered. The output voltage control mode or the output current control mode can be selected via the proposed strategy. In addition, a secondary-side losses compensation (SSLC) strategy is developed to deal with the non-ideal circuit characteristics as well as to enhance the control accuracy. Operational principles and thorough mathematical derivations will also be revealed. Finally, both simulation and experimental results obtained from a 100 W prototype circuit demonstrate the performance and feasibility of the proposed PSR and SSLC strategy. Validations show that the control accuracy of the output voltage and the output current are 98.54% and 98.42%, respectively.

Controllability analysis of Flyback converter with constant power load based on switched linear systems

A converter cascaded system is usually used for power conversion. However, due to the increase of the number of converters in the cascaded system, the amount of power switches and circuit elements also increases accordingly, which makes it difficult to analyze the dynamic characteristics and design control strategy. To understand the control theoretical characteristics of converter cascaded system and provide a theoretical basis for circuit parameters analysis and manipulation strategy design, taking the Flyback converter cascaded system as an example, this paper establishes an accurate switching linear systems model, discusses the control theoretical characteristics of the system in detail by using the controllability theorems. The simulations and experimental results prove the correctness of the analysis.

A Multifunctional, Non-Constant Current Charger Based on a Dual-Switching, Bidirectional Flyback Converter

This study implements a multifunctional charger based on a dual-switching, bidirectional flyback converter (DSBFC). The proposed charger adopts seven charging methods, including the incremental-current charging, constant-voltage (CV) charging, constant-current (CC) charging, pulse-current (PC) charging, triangular-current (TC) charging, sinusoidal-current (SC) charging, and positive/negative pulse-current (Reflex) charging methods. The charging process of a lithium-ion battery is divided into three stages: an initial term, a mid-term, and a final term. In the initial term, the incremental-current charging method is used in the initial term of charging for a soft start and to inhibit an increase in temperature. In the mid-term, five charging methods, including CC, PC, TC, SC, and Reflex-current charging, are used for charging. The CV charging method prevents overcharging the lithium-ion battery in the final term. Based on our experimental results, this study compares the four charging methods (PC, TC, SC, and Reflex-current) with the CC charging method to verify their improvement of the charging speed and increase in temperature in the mid-term. The charging speeds increased by 14.38%, 14.04%, 16.36%, and 27.27%, respectively, and the rise in temperature decreased by 37.8%, 40.5%, 48.6%, and 13.51%, respectively; all performed better than the CC charging method. Finally, users can adjust the charging method of the proposed DSBFC according to the needs of batteries so as to achieve excellent performance.

Piezoelectric energy harvesting for powering a novel weigh-in-motion system

• Roadway piezoelectric energy harvester (PEH) developed to power weigh-in-motion system. • PEH was tested under sinusoidal and pulse forces in the laboratory. • An electromechanical model associates applied forces on PZT stacks to output voltage. • The developed PEH circuit includes a rectifier, a capacitor, and a flyback converter. • Traffic forces exceeding flyback input thresholds generate sufficient power for MCU. This paper describes the development and evaluation of a piezoelectric energy harvester (PEH) designed to power a novel system for weighing roadway vehicles in-motion. The PEH consists of four lead zirconate titanate piezoelectric (PZT) stacks connected in parallel. Each stack is made of six PZT elements of alternating polarity. The paper describes the electromechanical characterization of the PZT stacks, the design of the PEH electronic circuit and its power generation potential under realistic traffic conditions. An electromechanical model was fitted to laboratory data that allows relating PZT stacks voltage output to the applied forces, as a function of loading frequency (i.e., vehicle speed). The PEH circuitry consists of a rectifier, a flyback and a step-down converter to reduce voltage output to the 0–3.3 V range. The flyback input thresholds were 100 V and 300 mW. At highway speeds, these thresholds were exceeded for sinusoidal forces with amplitudes higher than 13 kN. Exceeding these thresholds generated over 200 mW of power, which is sufficient for supporting the low-power microprocessors considered. The amplitude of intermittent pulsating forces that can exceed these thresholds were estimated as a function of the rest period between pulses. For a rest period of 60 ms (i.e., typical rest period between tandem truck axles), the estimated amplitude was 33.4 kN. It was shown that this force is exceeded by roughly 35% of the typical truck tires.

Switch Mode Power Supply (SMPS) Utilizing Flyback Converter Topology: Simulation and Experiment

This paper presents simulation and experimental works of a single, 5 volt DC output switch mode power supply (SMPS). The main objective of this work is to design, build and evaluate the SMPS using flyback converter topology. In this work, a 555 timer was chosen as the pulse width modulator. The 555 timer was chosen because it is easily available, cheap and has the capability to produce stable pulse width modulation. The complete circuit of the SMPS consist of full bridge rectifier, smoothing capacitor, pulse width modulator, high frequency transformer and flyback converter. The complete SMPS circuit was firstly designed and simulated using Proteus software. After obtaining acceptable results from the simulation process, the hardware part of the project, soon follows. Next, the SMPS circuit was constructed on a breadbroad. Testing and measurements of important parameters such as the input and output voltages and duty cycle were carried out using digital oscilloscope and multi meter. Both simulation and experimental results have shown that the designed circuit can convert single 24 Vrms 50 Hz AC voltage input into a stable single 5±0.15 V DC outputs. This work also has shown that pulsed DC voltage with peak value of 3.8 V and frequency lower than 4 kHz is adequate in controlling the switching frequency of a MOSFET transistor, thus regulating the output voltage within the desired range. Further analysis also shows close correlation between the simulation and experimental results.

A unipolar compact nanosecond pulsed power supply with high power factor for dielectric barrier discharge applications.

A high voltage with a very short duration and fast rising time is beneficial to generate uniform and diffuse plasma in dielectric barrier discharge (DBD) loads, and a power supply with a high power factor (PF) can reduce the impact on the power grid. According to two requirements, a unipolar high voltage pulsed power supply with power factor correction (PFC) is proposed in this paper. The power supply consists of a unipolar pulse high voltage generating unit, a PFC unit, and a driving circuit. By introducing a feedback clamping diode and a reverse current blocking diode in a flyback converter, repetitive nanosecond pulses are generated in the unipolar pulse high voltage generating unit. Because a discontinuous current mode strategy is adopted in the PFC unit and the driving signal is shared by the two units, a compact structure of the power supply is achieved, and a high PF is obtained. To validate the proposed pulsed power supply, an experimental setup is built for a DBD excimer lamp. The results show that the proposed power supply has the capability of not only providing a unipolar nanosecond pulse high voltage for the DBD excimer lamp but also achieving PF close to 1 and total harmonic distortion of less than 24%.

Digital Voltage Sampling Scheme for Primary-Side Regulation Flyback Converter in CCM and DCM Modes

Primary-side regulation (PSR) flyback topology with discontinuous conduction modulation (DCM) mode has been widely used in low-power application due to its high stability, wide input voltage range, low cost, and low standby power. To improve the output power, continuous conduction modulation (CCM) mode is always introduced. However, in CCM mode, conventional PSR voltage-sampling method cannot realize high precision of output voltage or the voltage sampling method requires complex control of high cost. In this paper, a simple digital voltage sampling scheme with two reference voltages outputted from a digital-to-analog converter (DAC) is put forward to trace the “accurate-point” voltage for DCM and CCM modes. In CCM mode, the sampling voltage error of the “knee-point” voltage can be compensated just by inserting DCM switching cycle to obtain the “accurate-point” voltage. Voltage difference between DCM mode and CCM mode will be eliminated, and high precision is easily realized. The proposed method is verified in a 20V, 65W PSR flyback converter. The sampling method only requires a low speed DAC, three comparators and a digital controller. The output voltage precision is within 0.6% with universal input voltage.