Design and Implementation of Self-Oscillating Flyback Converter With Efficiency Enhancement Mechanisms
TL;DR: A self-oscillating flyback converter with efficiency enhancement mechanisms using lossless snubber and the energy recovery winding and the burst-mode control mechanism to reduce the power consumption at the no-load and light-load conditions and increase the conversion efficiency.
Abstract: This paper presents a self-oscillating flyback converter with efficiency enhancement mechanisms using lossless snubber and the energy recovery winding The conventional self-oscillating flyback converter with resistor–capacitor–diode snubber has the issues of low conversion efficiency and high no-load power loss Furthermore, in order to fulfill the $95\ \mbox{V}_{\mathrm{p-p}}$ voltage limitation of the IEC62684 Common-Mode (CM) Standard, the parasitic capacitor of a transformer between the primary and secondary windings has to be reduced, which leads to large leakage inductance for the transformer However, the larger leakage inductance stores more energy to cause the high voltage spike on the main switch during the turnoff transition period Therefore, the lossless snubber is employed to suppress the voltage spike and increase the conversion efficiency In order to increase more conversion efficiency, the energy recovery winding is employed to recycle the energy discharged from the gate–source capacitor of the main switch Furthermore, the burst-mode control mechanism is utilized to reduce the power consumption at the no-load and light-load conditions Finally, a prototype circuit of the 75-W self-oscillating flyback converter with efficiency enhancement mechanisms is built to verify the performance feasibility, such as the CM voltage, the voltage stress on the switch, the conversion efficiency, and the no-load power loss
Citations
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TL;DR: An automatic any-cells-to-any-cells battery equalizer, which merges the forward and flyback converters through a common multiwinding transformer, which overcomes the mismatching problem of multiple windings and can reach up to 89.4% over a wide range of conditions.
Abstract: This paper proposes an automatic any-cells-to-any-cells battery equalizer, which merges the forward and flyback converters through a common multiwinding transformer. The windings of the transformer are divided into two groups, which have opposite polarities. The principles of the proposed equalizer are that the equalization in one group is achieved based on forward conversion and the balancing between the two different groups is based on flyback conversion, by which the magnetic energy stored in the transformer can be automatically reset without using additional demagnetizing circuits. Moreover, only one MOSFET and one primary winding are required for each cell, resulting in smaller size and lower cost. One pair of complementary control signals is employed for all MOSFETs, and energy can be automatically and directly delivered from any high-voltage cells to any low-voltage cells without the requirement of cell monitoring circuits, thereby leading to a high balancing efficiency and speed. The proposed topology can achieve the global equalization for a long battery string through connecting the secondary sides of transformers without the need of additional components for the equalization among modules, which also overcomes the mismatching problem of multiple windings. The validity of the proposed equalizer is verified through experiments, and the balancing efficiency can reach up to 89.4% over a wide range of conditions.
147 citations
TL;DR: In this article, the feasibility and effectiveness of implementing resonant gate drivers in widebandgap semiconductor transistors is discussed according to a detailed comparison of loss decomposition, and a case study of two representative gate driver topologies is given.
Abstract: The increasing transistor power loss brought by the high switching frequency places a limit to the future high power density converter design. A review of resonant gate drivers is given in this paper to provide a vision for its future application. Various resonant gate driver topologies from the prior-art research is categorized and thoroughly compared in terms of the implementation frequency and the percentage gate driver loss reduction. Moreover, a case study of two representative resonant gate driver topologies is given. The conventional gate drive and two resonant gate drivers are implemented to driver Silicon MOSFETs and Gallium Nitride transistors, respectively. The feasibility and effectiveness of implementing resonant gate drivers in wide-bandgap semiconductor transistors is discussed according to a detailed comparison of loss decomposition.
30 citations
Cites background from "Design and Implementation of Self-O..."
...Other applications of self-oscillating resonant gate driver can be found in [37] for the Class Φ 2 inverter and [38] for the flyback converter application....
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TL;DR: A self-oscillating boost converter with a blocking diode is proposed to meet the desire for simple, cost-effective, high performance, and highly efficient LED drivers and demonstrates several appealing advantages including design simplicity, robustness, soft-switching characteristics, tight current regulation, and high efficiency over a wide line/load range.
Abstract: In this paper, a self-oscillating boost converter with a blocking diode is proposed to meet the desire for simple, cost-effective, high performance, and highly efficient LED drivers. As compared with traditional self-oscillating converters, the proposed converter demonstrates several appealing advantages including design simplicity, robustness, soft-switching characteristics (zero-voltage switching and zero-current switching), tight current regulation, and high efficiency over a wide line/load range. The control stage is implemented with a compact and low-cost industry standard controller, which assumes multiple roles in switching and LED current regulation. A type III compensator with anti-windup is designed to limit the maximum LED current at startup and to achieve tight LED current regulation at steady state. The efficiency and desired transient/steady-state performances are verified with SPICE simulation and a prototype circuit, which demonstrate a maximum efficiency of 95.9% and 2.3% ripple factor for the LED current. The robustness of the proposed driver is verified under a range of power supply voltage and different numbers of LEDs at the load side. In addition, the circuit is modified to implement high efficiency pulsewidth modulation dimming between 5% and 95%.
22 citations
TL;DR: This paper presents a bidirectional single power-conversion dc-ac converter with noncomplementary active-clamp circuits that obtains high power efficiency and ensures high grid power quality and seamless mode transition.
Abstract: This paper presents a bidirectional single power-conversion dc–ac converter with noncomplementary active-clamp circuits. The proposed converter comprises a bidirectional flyback converter and an unfolding bridge. In order to interface the grid with a low-voltage energy storage through only single power-conversion, the bidirectional flyback converter transforms the low voltage directly into the folded grid voltage and regulates the folded grid current. The proposed converter adopts noncomplementary operation strategy for the active-clamp circuits. By using this strategy, the bidirectional flyback converter not only avoids the voltage spike but also minimizes the power losses by the circulating energy. Thus, with single power-conversion and noncomplementary active-clamp circuits, the proposed converter obtains high power efficiency. To facilitate the bidirectional single power-conversion, a novel control algorithm is developed. With this control algorithm, the proposed converter ensures high grid power quality and seamless mode transition. The proposed bidirectional dc–ac converter is theoretically analyzed in detail. The experimental results based on a 250-W prototype are provided to evaluate its performance.
15 citations
Cites background from "Design and Implementation of Self-O..."
...Despite of these advantages, the leakage energy of the transformer causes high voltage spike on the devices, in turn requires high voltage rating devices which cause high conduction loss [15], [16]....
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TL;DR: In this article, the authors presented a soft switched [zero voltage switching (ZVS)-pulse width modulation (PWM)] interleaved flyback converter with an average current mode control designed for remote power solutions.
Abstract: The growing need to supplement the depletion of conventional energy resources has placed an impetus on the electrical power industry to provide new avenues for alternative energy resources. This study presents a soft switched [zero voltage switching (ZVS)-pulse width modulation (PWM)] interleaved flyback converter with an average current mode control designed for remote power solutions. The flyback DC–DC converter, a popular choice for low-power DC applications that requires an electrical isolation, is being considered in this study due to its simplicity, cost and lesser magnetic components. The lower energy efficiency which is a drawback in flyback converters is overcome using the soft-switching technique. The switching losses and conduction losses are minimised using the ZVS-PWM technique. Also, interleaving of the DC–DC converters is being used to reduce the size of the magnetic components and further improve the converter efficiency. The effectiveness of the converter is verified using the results obtained through MATLAB/Simulink. A prototype model is also developed to validate this system and is tested using dsPIC30F4011 processor. The experimental results prove the viability of the converter. Both simulation and experimental results show high efficiency and good output voltage regulation for a wide range of load and input variations.
11 citations
References
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01 Jun 1978
TL;DR: In this paper, the authors present a theoretical analysis of transformer-inductor design, including the following: AC Inductor Design Powder Core. DC Inductor design Gap Core. Forward Converter Transformer and Inductor Development.
Abstract: Fundamentals of Magnetics. Magnetic Materials and Their Characteristics. Magnetic Cores, Iron Alloy and Ferrites. Window Utilization and Magnet Wire. Transformer-Inductor Design. Transformer-Inductor Efficiency, Regulation, and Temperature Rise. Power Transformer Design. DC Inductor Design Gap Core. DC Inductor Design Powder Core. AC Inductor Design. Constant Voltage Transformer Design (CVT). Three Phase Transformer Design. Flyback Converter Design. Forward Converter Transformer and Inductor Design. Input Filter Design. Current Transformer Design. Winding Capacitance and Leakage Inductance. Quiet Converter Design. Rotary Transformer Design. Planar Transformers. Derivation for the Design Equations. Index.
1,054 citations
"Design and Implementation of Self-O..." refers background in this paper
...However, the leakage inductances are also increased [23]....
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01 Jan 1991
TL;DR: In this paper, the authors proposed six single-transistor converter configurations with quadratic DC conversion ratios for high-frequency applications where the specified range of input voltages and output voltages call for an extremely large range of conversion ratios.
Abstract: Compared to basic converter topologies (buck, boost, buck-boost, Cuk, etc.), pulse-width modulation (PWM) converters with quadratic DC conversion ratios, M(D)=D/sup 2/, M(D)=D/sup 2//(1-D) or M(D)=D/sup 2//(1-D)/sup 2/, offer a significantly wider conversion range. For a given minimum ON-time and, consequently, for a given minimum duty ratio D/sub min/, D/sup 2/ in the numerator of M(D) yields a much lower limit on the minimum attainable conversion ratio. By applying a systematic synthesis procedure, six novel single-transistor converter configurations with quadratic DC conversion ratios are found. The simpler, single-transistor realization is the most important advantage over the straightforward cascade of two basic converters. As far as conversion efficiency is concerned, it is clear that a single-stage converter is usually a better choice than a two-stage converter. The quadratic converters proposed are intended for applications where conventional single-stage converters are inadequate-for high-frequency applications where the specified range of input voltages and the specified range of output voltages call for an extremely large range of conversion ratios. >
651 citations
"Design and Implementation of Self-O..." refers background in this paper
...The typical non-isolated stepdown converters include buck and buck–boost converters [4]–[8]....
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20 Jun 1994
TL;DR: In this paper, the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current is analyzed and design equations based on this analysis are presented.
Abstract: Flyback derived power convertor topologies are attractive because of their relative simplicity when compared with other topologies used in low power applications. Incorporation of active-clamp circuitry into the flyback topology serves to recycle transformer leakage energy while minimizing switch voltage stress. The addition of the active-clamp circuit also provides a mechanism for achieving zero-voltage-switching (ZVS) of both the primary and auxiliary switches. ZVS also limits the turn-off di/dt of the output rectifier, reducing rectifier switching losses, and switching noise due to diode reverse recovery. This paper analyzes the behavior of the ZVS active-clamp flyback operating with unidirectional magnetizing current and presents design equations based on this analysis. Experimental results are then given for a 500 W prototype circuit illustrating the soft-switching characteristics and improved efficiency of the power converter. Results from the application of the active-clamp circuit as a low-loss turn-off snubber for IGBT switches is also presented.
421 citations
TL;DR: This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments.
Abstract: Solid-state switch mode AC-DC converters having high-frequency transformer isolation are developed in buck, boost, and buck-boost configurations with improved power quality in terms of reduced total harmonic distortion (THD) of input current, power-factor correction (PFC) at AC mains and precisely regulated and isolated DC output voltage feeding to loads from few Watts to several kW. This paper presents a comprehensive study on state of art of power factor corrected single-phase AC-DC converters configurations, control strategies, selection of components and design considerations, performance evaluation, power quality considerations, selection criteria and potential applications, latest trends, and future developments. Simulation results as well as comparative performance are presented and discussed for most of the proposed topologies.
368 citations
"Design and Implementation of Self-O..." refers methods in this paper
...For safety consideration, the isolated stepdown converter is applied to the ac–dc stepdown adapter for the portable product [14]–[17]....
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...Self-oscillating flyback converter with RCD snubber [13], [14]....
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TL;DR: In this paper, the authors proposed a burstmode control for LLC resonant converter to improve the light-load efficiency by optimizing the first pulse width and the next two pulse operation to achieve high burst efficiency.
Abstract: The LLC resonant converter has drawn much attention for high efficiency. However, its light-load efficiency still cannot meet the ever increasing requirements. This paper proposes a novel burst-mode control for the LLC resonant converter to improve the light-load efficiency. Based on the state-plane trajectory analysis, during the burst-on time, a three-pulse switching pattern is implemented. By optimizing the first pulse width, the state variables are settled to the steady state of the highest efficiency load in the minimal time, and then, the next two pulse operation follows this steady-state trajectory to achieve high burst efficiency. Moreover, when the load changes, the burst-on time with the optimal three-pulse switching pattern is maintained, but the burst-off time is modulated. As a result, the output-voltage low-frequency ripple minimally keeps constant, and no additional filter is needed. Experimental results validate the proposed techniques.
207 citations
"Design and Implementation of Self-O..." refers methods in this paper
...In order to reduce the no-load power loss of the ac–dc adapter, the burst-mode control was proposed [31], [32] and also can be achieved by the self-oscillating flyback converter....
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