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Showing papers on "Flyback converter published in 2019"


Journal ArticleDOI
TL;DR: Bidirectional resonant dc transformer (BRDT) is proposed to replace the conventional bulky transformer for bus voltage matching and galvanic isolation and 50% duty ratio scheme is implemented as it has been proven to be better than the phase-shift scheme in order to ensure BRDT conversion efficiency.
Abstract: As a reliable device for voltage regulation and isolation, a line frequency transformer is commonly connected in series with bidirectional converter (BIC) to interlink the ac and dc networks of hybrid ac/dc microgrid. However, it may not be suitable for the applications where weight and space occupation are of important concerns such as hybrid ac/dc microgrid. In this paper, bidirectional resonant dc transformer (BRDT) is proposed to replace the conventional bulky transformer for bus voltage matching and galvanic isolation. In order to simplify systematic coordination with BIC and central controller, BRDT is designed as an ideal transformer with simple open-loop scheme. 50% duty ratio scheme is implemented as it has been proven to be better than the phase-shift scheme in order to ensure BRDT conversion efficiency. A generalized model for various BRDT topologies, including CLLC, CLL, and LLC high frequency transformer (HFT), is established for analysis. The impacts induced by the transformer leakage, magnetizing inductances, and extra resonant capacitors are considered when designing the HFT. The conversion gain of the designed BRDT has also been analyzed in the full power range. Lab-scale prototypes for BRDT and hybrid ac/dc microgrid have been developed for experimental verifications. The performances of BRDT and system in both steady and transient states have been confirmed.

65 citations


Journal ArticleDOI
TL;DR: A unitized multiwinding transformer-based equalization method that can equalize well both for the cells in different subunits and in the same subunit, and has achieved a good performance in terms of system cost, control complexity, and speed.
Abstract: Active equalization is an efficient method to improve the performance of series-connected battery strings for the electric vehicles. However, the large-scale applications of the active equalization are restricted by many factors, such as system cost, control complexity, and equalization speed. In this paper, a unitized multiwinding transformer-based equalization method is proposed. The forward converter and flyback converter are realized, simultaneously. The forward converter principle is used to equalize the battery cells in the same subunit, while the flyback converter principle is applied for the equalization of the different subunits. Fewer metal-oxide-semiconductor field-effect transistors and transformer windings are needed for lower control complexity and lower system cost. Furthermore, different subunits of the battery string can be simultaneously equalized, resulting in higher time efficiency. To verify the proposed method, the simulation and experimental workbenches are established. Results indicate that the proposed method can equalize well both for the cells in different subunits and in the same subunit. The urban dynamometer driving schedule tests are further applied and the unbalanced problem is covered in about one hour. The results show that the proposed method has achieved a good performance of equalization in terms of system cost, control complexity, and speed.

64 citations


Journal ArticleDOI
TL;DR: This paper proposes an observer-based control strategy that uses a parameter estimate to update the control law in real time and preserves the stability property when the Flyback converter works in the so-called discontinuous conduction mode (DCM).

47 citations


Journal ArticleDOI
Peng Cao1, Yao Qian1, Pan Xue1, Danzhu Lu2, Jie He2, Zhiliang Hong1 
TL;DR: The open-circuit voltage maximum power point tracking (MPPT) method is adopted in this harvester to extract as much energy as possible from the thermoelectric generator by dynamically adjusting the switching frequency according to the input power.
Abstract: This paper presents a bipolar-input thermoelectric energy-harvesting interface based on boost/flyback hybrid converter (BFHC). Two-type ring oscillators are combined to form as a complementary group with bipolar-input voltage operating range for self-start. With the technique of combining the boost converter and flyback converter together, the system is able to convert the energy with bipolar-input voltages. The open-circuit voltage maximum power point tracking (MPPT) method is adopted in this harvester to extract as much energy as possible from the thermoelectric generator. By dynamically adjusting the switching frequency according to the input power, the system achieves a high conversion efficiency with a wide input range. Implemented in 180-nm CMOS process, the harvester achieves a peak conversion efficiency of 84% at $V_{{\text {TEG}}}=260$ mV and 79% at $V_{{\text {TEG}}}=-300$ mV. In addition, the harvester can self-startup with minimum voltages of 129 mV with a positive input voltage and −140 mV with a negative input voltage.

36 citations


Journal ArticleDOI
TL;DR: This article proposes an improved measurement technique to address two measurement issues in CM current and impedance measurement, including the poor measurement resolution for the low noise voltage in the high-frequency range due to the high magnitude of line-frequency voltages and the loading effects of the voltage probe.
Abstract: For the radiated electromagnetic interference pre-compliance diagnosis in power electronics systems, the measurement of common mode (CM) currents, impedances, and voltages are essentially important. In this article, two measurement issues are first identified in CM current and impedance measurement. The first is the coupling between the cables attached to a power converter and the coaxial cable connected to the measurement equipment. It degrades the measurement accuracy. The second is the coupling between the converter's attached cables and the ac grid. It degrades the repeatability of measurements. To improve the measurement accuracy and repeatability, this article proposes an improved measurement technique to address these two issues. Furthermore, for the measurement of the voltage difference between primary and secondary grounds, this article also identifies two issues. The first is the poor measurement resolution for the low noise voltage in the high-frequency range due to the high magnitude of line-frequency voltages. The second is that the loading effects of the voltage probe can reduce the measurement accuracy. This article proposed a technique to address these two issues. Finally, the proposed measurement techniques were validated on a flyback converter.

34 citations


Journal ArticleDOI
TL;DR: In this paper, an integrated, dual-output gate-drive power supply for gallium-nitride (GaN) 650-V, 60-A, half-bridge phase legs, rated at 2 W (2 × 1 W), 15 to 2 × 7 V, featuring an ultralow $C_{i}$ of 1.6 pF, a power density of 72 W/in3, and an efficiency of 85%.
Abstract: Wide-bandgap devices have been widely used to reduce the size and increase the efficiency of power converters by operating at a high switching frequency, at the expense of heightened radiated and conducted electromagnetic inference (EMI) emissions, of which the latter circulates through the power loop and ancillary circuitry. In effect, the parasitic isolation capacitance $C_{i}$ of the gate-driver power supply represents a key EMI propagation path to be controlled in order to ensure the operational integrity of power converters. To this end, this paper proposes an integrated, dual-output gate-drive power supply for gallium-nitride (GaN) 650 V, 60 A, half-bridge phase legs, rated at 2 W (2 × 1 W), 15 to 2 × 7 V, featuring an ultralow $C_{i}$ of 1.6 pF, an output-to-output parasitic capacitance of 1.6 pF, a power density of 72 W/in3, and an efficiency of 85%. All this is attained using an active-clamp flyback converter switching at 1 MHz using 65 V GaN high-electron-mobility transistor devices and Schottky output rectifiers, and a Pareto-optimized transformer design minimizing its interwinding capacitances, volume, and losses. Finally, the transformer is fully embedded in a printed circuit board (PCB) material, doubling as a substrate for the topside active layer of the power supply. The paper presents the complete design procedure, processing, and experimental demonstration of the proposed integrated power supply, evaluating as well the reliability impact of the magnetic-PCB material interface in high ambient temperature applications (>200 °C).

33 citations


Proceedings ArticleDOI
17 Mar 2019
TL;DR: In this paper, the equivalent core loss resistance and its application on CM inductors for radiated EMI reduction were investigated and quantified in terms of the ratio of core's cross section area over core's magnetic path length and winding's turns number.
Abstract: In power converters, common mode (CM) noise can radiate to cause radiated electromagnetic interference (EMI). Resistive, inductive and capacitive parts of the CM inductors can interact with the antenna to induce damping effect or additional resonance. The resistive component is desired for radiated EMI reduction with resonance avoided and noise energy dissipated. This paper researches on the equivalent core loss resistance and its application on CM inductors for radiated EMI reduction. This paper investigates the equivalent core loss resistance and quantifies its relation with core parameters and winding parameters. Critical factors for the equivalent core loss resistance include the ratio of core’s cross section area over core’s magnetic path length and winding’s turns number. Capacitive part of the CM inductor is also considered given its influence on impedance and on radiated EMI. Parasitic capacitances of both the winding and the core are analyzed. Experimental verification on the core loss based CM inductor design is performed on a flyback converter, with radiated EMI measured in a semi-anechoic chamber.

30 citations


Journal ArticleDOI
TL;DR: In this article, the authors proposed a new online capacitance and ESR monitoring scheme for the output electrolytic capacitor in a discontinuous conduction mode (DCM) flyback converter.
Abstract: In a power electronics system, an electrolytic capacitor (E-Cap) is widely used, whose performance degradation can be reflected by the change of capacitance ( C ) and equivalent series resistance (ESR) This paper proposes a new online C and ESR monitoring scheme for the output electrolytic capacitor in a discontinuous conduction mode (DCM) flyback converter The mathematical relationship between the instantaneous capacitor voltage and other parameters is analyzed and then the scheme of undetermined coefficients based on the multiple-spot sampling and least square method is further proposed In addition, considering the particularity of high ripple current and the resultant voltage ripple variation range, especially with the temperature, an inverse ripple voltage isolation amplifier with variable amplification factor and negative voltage elimination is put forward so as to make digital signal processor identify the temperature change easily The proposed scheme is noninvasive as only voltage signals need to be sampled and no current sensor is necessary A prototype is built and the experiments are made to verify the effectiveness of the proposed method, from which the data are in accordance with the results measured by an LCR meter

29 citations


Journal ArticleDOI
TL;DR: This paper presents a novel switch current stress reduction technique for a single switch boost-flyback high step up dc–dc converter that increases the effective inductance of the coupled inductor primary winding during switch turn-on operation and helps to reduce current stress.
Abstract: This paper presents a novel switch current stress reduction technique for a single switch boost-flyback high step up dc–dc converter. Coupled inductor-based converters do not have a sufficiently higher inductance value of their windings. This creates current surge during transient and steady state, which in turn increases current stress at main switch. To compensate this difficulty in coupled inductor-based boost flyback converter, an inductor–diode parallel combination has been connected in series with the switch. This technique increases the effective inductance of the coupled inductor primary winding during switch turn- on operation and helps to reduce current stress. Steady-state operating principle with the proposed technique is analyzed in continuous conduction mode. The current reduction technique is discussed with a proper mathematical derivation. To verify theoretical findings, simulation study is carried out in MATLAB/Simulink R2014b. Finally, a laboratory-based 40-W prototype converter is designed to show the effectiveness of the proposed switch current reduction technique.

28 citations


Journal ArticleDOI
TL;DR: In this article, an improved bridgeless Cuk converter-based electric vehicle (EV) battery charger with high power factor and increased efficiency is designed and developed, which provides low cost and high power density-based charging solution for the EV.
Abstract: An improved bridgeless (BL) Cuk converter-based electric vehicle (EV) battery charger with high power factor and increased efficiency is designed and developed in this paper. It provides low cost and high-power-density-based charging solution for the EV. This charger incorporates less number of devices operating over one switching cycle, which reduces the additional conduction loss incurred by a diode bridge rectifier of the conventional charger. Hence, it improves the charger's efficiency. The added advantage of the proposed topology is that the unwanted capacitive coupling loop is removed, as well as the unwanted conduction through the body diode of the inactive switch in the previously developed BL Cuk converter is avoided. This significantly improves the charger's efficiency. For the constant current and constant voltage charging, the commands are synchronized by a flyback converter. The proposed charger draws a sinusoidal current from ac mains and the total harmonic distortion in the supply current is reduced to the limits specified by the IEC 61000-3-2 guidelines. The improved efficiency and power quality indices of the proposed charger are investigated to demonstrate its satisfactory charging operation at all operating conditions.

28 citations


Journal ArticleDOI
TL;DR: A 100-W prototype is presented under the experimental condition to validate the proposed integrated-stage LED driver and a cost-effective MOSFET can be chosen as the main control component that can decrease the cost of the whole system.
Abstract: This paper presents a novel integrated-stage light-emitting diode (LED) driver based on Flyback and resonant converters. The Flyback converter realizes power factor correction in the discontinuous conduction mode. The resonant converter is operated as a dc–dc converter to support the LED loads. Moreover, the resonant converter can clearly decrease the drain–source voltage of the active switch and exhibits zero-voltage-switch characteristics. Therefore, a cost-effective MOSFET can be chosen as the main control component that can decrease the cost of the whole system. Compared to a single-active-switch converter (such as Class-E converter), the number of passive components in the resonant converter can be limited to four. Therefore, the power density of the system can be improved drastically. In this paper, a 100-W prototype is presented under the experimental condition to validate the proposed integrated-stage LED driver.

Journal ArticleDOI
TL;DR: A novel isolated bidirectional two-switch flyback converter with two integrated non-dissipative inductor–capacitor–diode (LCD) snubbers is proposed to reduce the current circulation and improve the conversion efficiency.
Abstract: This paper proposes a novel isolated bidirectional two-switch flyback converter with two integrated non-dissipative inductor–capacitor–diode (LCD) snubbers. In the proposed topology, the main flyback transformer and the LCD snubbers are cross coupled to minimize circulating current that would occur in the non-cross-coupled case, in addition to recycle leakage energy and protect the power transistors. The same current circulation issue also occurs in the bidirectional flyback converter with conventional resistor–capacitor–diode (RCD) snubbers. The main objective of this paper is to illustrate this issue and propose an alternate circuitry to reduce the current circulation and improve the conversion efficiency. The experimental results of a laboratory prototype are reported to verify the design.

Journal ArticleDOI
TL;DR: In this article, a high-accuracy constant output current/constant output voltage (CC/CV) ac-dc flyback converter is proposed and a novel cable compensation method without external capacitor is put forward.
Abstract: With the development of portable electronic products, the requirement for chargers is also getting higher. In this paper, a high-accuracy constant output current/constant output voltage (CC/CV) ac–dc flyback converter is proposed and a novel cable compensation method without external capacitor is put forward. The converter adopts primary-side regulation (PSR) scheme, detecting the output voltage through the auxiliary winding, and adjusting switching frequency to achieve output voltage constant in CV mode. Compared to conventional cable compensation module, the proposed circuit applies a method of pre-filtering, averaging, and re-filtering, to obtain the compensation voltage. This method eliminates the need of external capacitor, reducing cost and increasing reliability of the converter. In CC mode, the switching period is adjusted to be fixed multiple of the demagnetization time, thereby realizing the constant current output. The control chip was implemented in NEC 1 μm HVCMOS process, and a 5-V/1-A prototype has been built to verify its feasibility. Experimental results show that the deviations of output voltage and current are within ±0.9% and ±3% under different inputs and loads, while maximum conversion efficiency can reach a level of 78.2%.

Journal ArticleDOI
TL;DR: A comparison of topologies for a three-port converter to charge EVs directly from photovoltaic panels is presented, and the best topology is chosen based on the number of components, converter efficiency, volume, controllability and current ripple.
Abstract: Charging of electric vehicles (EVs) from solar energy provides a sustainable means to power EVs in the future. A comparison of topologies for a three-port converter to charge EVs directly from photovoltaic (PV) panels is presented in this study. The grid-connected EV charger has a nominal rating of 10 kW and is bidirectional, enabling vehicle-to-grid operation. The topologies are optimally designed considering different switching frequencies, silicon carbide devices, magnetic cores and number of interleaved stages. Nine topologies are compared using a comparison framework, and the best topology is chosen based on the number of components, converter efficiency, volume, controllability and current ripple. The analysis shows that the best topology is a three-port converter with a central direct current link with a 3-leg interleaved boost converter (IBC) for the PV, two-level inverter with sinusoidal modulation for the grid and a 4-phase interleaved flyback converter for the EV. The loss models built are experimentally verified using a 3-leg IBC.

Proceedings ArticleDOI
13 May 2019
TL;DR: The number of active switches are reduced, resulting in less losses and more efficient, in the flyback converter cell balancing method for lithium based batteries in ultralight Electrical Vehicle (EV).
Abstract: In This paper, the concept of flyback converter cell balancing method for lithium based batteries in ultralight Electrical Vehicle (EV) is investigated. In electrical vehicles, Battery Management System (BMS) plays and important role, in order to achieve a reasonable life time and best performance. A cell balancing circuit is essential to equalize each battery cell as the same voltage level in a series battery cells. Among cell balancing method, flyback converter balancing method has fast balancing time. It has N secondaries for N cells. It only requires one switch and N diodes at the output for each cell. Therefore, the number of active switches are reduced, resulting in less losses and more efficient. In this paper, eight cells are investigated to be equalized. The primary is supplied by the total battery pack, which is controlled by N-channel MOSFET. The switch will be turn ON and OFF with 50% duty cycle. The simulation results are performed to testify the variability of the proposed system.

Journal ArticleDOI
TL;DR: An accurate unified small-signal model for VFPCM control in continuous conduction mode (CCM) and discontinuous conduction modes (DCM) is proposed and a compensation strategy is proposed to overcome the unstable problem in a wide range of operations and give engineers insight.
Abstract: Flyback converter with variable-frequency peak-current-mode (VFPCM) control is widely used in low-power adaptor and recently proposed universal serial bus power delivery application. The control scheme achieves high efficiency for the entire load range by reducing the switching frequency at light load. In the present study, an accurate unified small-signal model for VFPCM control in continuous conduction mode (CCM) and discontinuous conduction mode (DCM) is proposed. Based on the model, a compensation strategy is proposed to overcome the unstable problem in a wide range of operations and give engineers insight. Experimental and simulation results verify the proposed model and compensation strategy.

Journal ArticleDOI
TL;DR: The proposed multipurpose power electronic interface competent of utilising dual sources during charging process has been proposed for plug-in electric vehicles and keeps isolation in each mode, which results in better safety for battery as well as vehicle users.
Abstract: In this research work, a multipurpose power electronic interface (PEI) competent of utilising dual sources during charging process has been proposed for plug-in electric vehicles. Based on the requirement, the battery can either be charged from solar photovoltaic (SPV) or from the grid. Moreover, when charged from an SPV source, converter can extract highest available power with maximum power point tracking (MPPT). The intrinsic novelty of the proposed PEI is that no additional components/switches are employed to achieve dual sources in charging or for MPPT. The proposed PEI consists of a converter derived from a conventional isolated secondary ended primary inductance converter (SEPIC). It is designed to operate effectively in all vehicular modes (charging, propulsion (PP) and regenerative braking (RB)). During battery charging from the grid and SPV, it operates as isolated SEPIC. While, in PP and RB, it operates as a flyback converter. Therefore, the proposed converter keeps isolation in each mode, which results in better safety for battery as well as vehicle users. Further, all vehicular modes are achieved through a single converter. As a result, compactness of the charger increases and making it best solution for on-board battery charging application.

Journal ArticleDOI
Chong Wang1, Shen Xu1, Shen Weidong1, Shengli Lu1, Weifeng Sun1 
TL;DR: In this article, a single-switched quasi-resonant flyback converter that features low switching loss and low switching noise at high switching frequency is investigated in order to realize near fully soft switching, a resonant inductor of primary side and an resonant capacitor of secondary side are utilized to recycle the transformer leakage energy and realize zero-current switching at turn off and valley switching (VS) at turn on of the primary switch.
Abstract: The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. A single-switched quasi-resonant flyback converter that features low switching loss and low switching noise at high switching frequency is investigated in this paper. In order to realize near fully soft switching, a resonant inductor of primary side and a resonant capacitor of secondary side are utilized to recycle the transformer leakage energy and realize zero-current switching (ZCS) at turn off and valley switching (VS) at turn on of the primary switch, and ZCS at turn off of diode. The VS is utilized based on the resonance between the resonant inductor and the equivalent switch drain capacitor. In the closed-loop control, a pulse frequency modulation mode with time fluctuation of switching period is implemented to realize VS at turn on of switch and an on – off control mode is utilized to improve the overall efficiency. Low cost, low losses, and low switching noise are all realized in the proposed prototype. The proposed concept has been validated on a 1 MHz 12 V/3 A prototype with 80 V dc input. The peak efficiency is 90.3% in the on – off mode by using GaN device without synchronous rectification.

Proceedings ArticleDOI
01 Sep 2019
TL;DR: In this article, a flyback DC-DC converter operated with variable switching frequency is studied and the proposed topology is operated with lower frequencies at light load conditions compared to rated output power.
Abstract: Flyback converter, one of the switching power supply circuit with high frequency, is widely used in low power applications due to its cost effectiveness and electrical isolation characteristics. It is known that high frequency causes switching losses and reduces the efficiency of converters especially at low power ratings. Therefore, a flyback DC-DC converter operated with variable switching frequency is studied in this study. The proposed topology is operated with lower frequencies at light load conditions compared to rated output power. The results obtained from the variable switching converter are compared with the results obtained from constant switching frequency flyback topology for the same input/output conditions. It is observed that the flyback converter operated with variable switching frequency is more efficient than the flyback converter operated with constant frequency.

Proceedings ArticleDOI
Shen Xu1, Chong Wang1, Qinsong Qian1, Jing Zhu1, Weifeng Sun1, Haisong Li 
17 Mar 2019
TL;DR: In this article, a high-switching-frequency single-switched quasi-resonant flyback converter that features low switching loss and low switching noise is proposed, where a resonant inductor of primary side and a resonance capacitor of secondary side are utilized to recycle the transformer leakage energy and realize zero-current switching (ZCS) at turn-off and valley switching (VS) at turning-on of the primary switch, and ZCS turnoff of diode.
Abstract: In The demand of miniaturization of power systems has accelerated the research on high-switching-frequency power converters. In this paper, a high-switching-frequency single-switched quasi-resonant flyback converter that features low switching loss and low switching noise is proposed. A resonant inductor of primary side and a resonant capacitor of secondary side are utilized to recycle the transformer leakage energy and realize zero-current-switching (ZCS) at turn-off and valley-switching (VS) at turn-on of the primary switch, and ZCS turn-off of diode. The VS is realized based on the resonance between the resonant inductor and the equivalent switch drain capacitor which helps to realize near fully soft switching. Compared to traditional quasi-resonant converters, the switching loss is greatly reduced. And low cost, low losses and low switching noise are all acquired. The proposed concept has been validated on a 1MHz 12V/3A prototype with 80V dc input. The peak efficiency is 90.4% using GaN device without synchronous rectification in the open loop test.

Journal ArticleDOI
TL;DR: In this article, an improved electric vehicle (EV) battery charger with a non-inverting output voltage-based bridgeless power factor correction (PFC) Cuk converter and a flyback converter is proposed for controlling the battery current in constant-current-constant-voltage charging regions.
Abstract: This study proposes an improved electric vehicle (EV) battery charger with a non-inverting output voltage-based bridgeless power factor correction (PFC) Cuk converter and a flyback converter for controlling the battery current in constant-current-constant-voltage charging regions. The proposed EV charger eliminates the need for an extra inverse amplifier, which is used for the negative to positive output voltage conversion in a conventional Cuk PFC converter. Therefore, the control of the converter is easy to implement and the cost of the charger is also reduced. Moreover, the design of the charger is proposed for discontinuous conduction mode operation, which comes with the inherent advantages of reduced sensors, low reverse recovery in diodes, and zero current switching. The proposed EV charger, with improved efficiency, operates satisfactorily to comply with the IEC61000-3-2 standard for power quality at steady state and for sudden perturbations in mains voltage.

Journal ArticleDOI
TL;DR: The proposed approach takes advantage of operating under discontinuous conduction mode to shape the input current into sinusoidal form inherently and demonstrate efficiency of 93% at nominal load condition.
Abstract: In this paper, a new soft-switching bridgeless single-phase power factor correction converter is introduced and analyzed. Employing an auxiliary flyback circuit, existing dead angle in the input current is eliminated while softswitching is achieved. The flyback converter processes only small amount of output power. Therefore, conduction losses of its bridge diode and semiconductor devices are low. Also, the auxiliary flyback converter provides soft-switching condition for buck switches. All semiconductors are turned on and off under soft-switching condition. In addition to reduction of switching losses, diode's reverse-recovery problems are eliminated due to soft-switching condition. The proposed approach takes advantage of operating under discontinuous conduction mode to shape the input current into sinusoidal form inherently. Experimental results are reported for a 120-W prototype at 110 Vrms input and 48-V output. The results demonstrate efficiency of 93% at nominal load condition. Furthermore, the input current harmonics fulfill IEC61000-3-2 (Class D) standard as well.

Journal ArticleDOI
TL;DR: In this paper, the authors proposed a methodology, based on the converter output characteristics, to standardize the analysis of voltage-balance mechanism in steady state, which allows understanding the behavior of voltage sharing among the modules in steady-state, in the presence of mismatched parameters for the ISOS connection of modular converters.
Abstract: The voltage-balance mechanism is a required ability to simplify the control scheme for modular input-series and output-series ( $\text{ISOS}$ ) connection, in spite of the fairly large number of studies, such mechanism has not been addressed clearly and satisfactory. This paper proposes a methodology, based on the converter output characteristics, to standardize the analysis of voltage-balance mechanism in steady state, which allows understanding the behavior of voltage sharing among the modules in steady state, in the presence of mismatched parameters for $\text{ISOS}$ connection of modular converters. In addition, the $\text{ISOS}$ connected modular two-switch flyback converter is presented. The intrinsic voltage-balance mechanism, even operating in continuous conduction mode, make this converter feasible, as an alternative to the predecessors modular converters. The operation and analysis of the proposed connection were corroborated, based on the experiment carried out on a laboratory prototype with three modules: ${\text{1}}, {\text{200 V}}_{\text{dc}}$ total input voltage, ${\text{1.5 kW}}$ rated power, and $\text{50 kHz}$ switching frequency. This paper is accompanied by a video demonstrating the operation, in steady state, of the laboratory prototype.

Journal ArticleDOI
TL;DR: This paper presents a high power factor (PF), low total harmonic distortion (THD) light-emitting diode (LED) driver with dimming capability, implemented by using an interleaved capacitor, which is placed between the rectifier and the integrated buck flyback converter (IBFC).
Abstract: This paper presents a high power factor (PF), low total harmonic distortion (THD) light-emitting diode (LED) driver with dimming capability. In addition, the proposed technique ensures a high PF and low THD at any dimming level. The driver is implemented by using an interleaved capacitor, which is placed between the rectifier and the integrated buck flyback converter (IBFC). In this way, the line current conduction angle is increased, which in return increases the PF and decreases the THD. The operation of the proposed converter ensures that one diode of the conventional IBFC will not conduct, so that it can be removed. Moreover, owing to the continuous power flow, the proposed technique makes a significant reduction of the converter output ripple. The paper presents a prototype of the proposed converter supplying an LED luminaire of 37 V/ 0.67 A. The prototype shows a high PF of 0.997, small THD of 2.5%, output current ripple of 6%, and an efficiency of 80%.

Journal ArticleDOI
TL;DR: This paper proposes data transmission method between primary and secondary of the flyback converter without additional communication circuit while simultaneously transferring power, thus adding communication function while not increasing the volume of the terminal and overall system.
Abstract: This paper proposes data transmission method between primary and secondary of the flyback converter without additional communication circuit while simultaneously transferring power. In some application such as a battery charger, the data exchanges between the primary and secondary sides are necessary. In the conventional system, an additional line or wireless communication modules is used for data exchanges, thereby increasing the system and connector size. The proposed system, in comparison, does not use additional signal transceiver but instead exchanges data by simply alternating operation mode of the flyback converter, thus adding communication function while not increasing the volume of the terminal and overall system. The waveform of transformer voltage is used to count the number of resonant pulses, which is used for decoding and encoding the data packet. Bidirectional communication between primary and secondary sides is possible while power is transferred to the output using an appropriate communication protocol. This paper proposes data transmission method for both single output and the multioutput cases. Also, both half-duplex and full-duplex communication using the proposed method is explained. The experimental results are presented to verify the performance of the proposed communication method.

Journal ArticleDOI
TL;DR: A novel dc-to-dc converter that mainly consists of two interleaved flyback converters that can achieve zero-voltage switching on without the use of any active clamp circuit or snubber circuit is presented.
Abstract: Flyback converter has advantages of simple circuit configuration and easy control. However, it suffers two problems. One is the active switch is hard switching. The other is a very high voltage spike when the active switch is turned off . In order to solve these problems, this paper presents a novel dc-to-dc converter that mainly consists of two interleaved flyback converters. Both active switches can achieve zero-voltage switching on without the use of any active clamp circuit or snubber circuit. In addition, the leakage flux energy can be delivered to the output by using two added diodes. It helps to reduce the voltage spikes on the active switches and improve circuit efficiency. The steady-state analyses at different operation modes and the mathematical equations for parameters design are provided. Finally, a 200-W prototype circuit for driving high-brightness light-emitting diodes (LEDs) is built and tested to verify the feasibility of the proposed circuit. The LEDs are dimmed from 100% to 10% full power. Satisfactory performances are obtained from the experimental results.

Journal ArticleDOI
05 Jun 2019-Energies
TL;DR: A DC grid that can be used for a household in a distant or rural area to power the aforementioned, utilizing Solar PV is suggested.
Abstract: Various statistics indicate that many of the parts of India, especially rural and island areas have either partial or no access to electricity. The main reason for this scenario is the immense expanse of which the power producing stations and the distribution hubs are located from these rural and distant areas. This emphasizes the significance of subsidiarity of power generation by means of renewable energy resources. Although in current energy production scenario electricity supply is principally by AC current, a large variety of the everyday utility devices like cell phone chargers, computers, laptop chargers etc. all work internally with DC power. The count of intermediate energy transfer steps are significantly abridged by providing DC power to mentioned devices. The paper also states other works that prove the increase in overall system efficiency and thereby cost reduction. With an abundance of solar power at disposal and major modification in the area of power electronic conversion devices, this article suggests a DC grid that can be used for a household in a distant or rural area to power the aforementioned, utilizing Solar PV. A system was designed for a household which is not connected to the main grid and was successfully simulated for several loads totaling to 250 W with the help of an isolated flyback converter at the front end and suitable power electronic conversion devices at each load points. Maximum abstraction of operational energy from renewable sources at a residential and commercial level is intended with the suggested direct current systems.

Journal ArticleDOI
TL;DR: An input-series flyback converter with the coupled-inductor-based passive snubber is proposed, where the input- series converter is based on transformer integration, and the passive snubs is composed of inductors, capacitors, and diodes.
Abstract: In this paper, an input-series flyback converter with the coupled-inductor-based passive snubber is proposed, where the input-series converter is based on transformer integration, and the passive snubber is composed of inductors, capacitors, and diodes The inductors of the snubber in various series modules are made on a common magnetic core, and the coupled-inductor scheme is adopted With the help of the coupled inductor, active input voltage sharing of the input-series converter can also be achieved after the switches are turned off , and voltage sharing of the switch in each series module can be ensured, which overcome the shortcomings of the existing input-series flyback converter Active voltage sharing processes caused by the coupled inductor are analyzed in detail Furthermore, the design guideline of the passive snubber is discussed Finally, the experimental study has been done on a 1500 Vdc/60 W laboratory-made prototype composed of three flyback series modules, and the feasibility of the proposed method and the theoretical analysis is verified by the experimental results

Journal ArticleDOI
TL;DR: In this paper, a dc-dc high-gain converter using coupled inductors is presented, and the results obtained were coherent, with no significant semiconductor over-voltage and high efficiency was achieved for a wide power range.
Abstract: Combining low-voltage power sources with loads that require high-voltage levels is a challenge, especially for power devices above 500 W. In this context, this study presents a new dc-dc high-gain converter using coupled inductors. The new converter uses only one switch and output capacitors with low values. It also allows the use of energy from the leakage inductors and enables the input current to operate in the continuous mode. The experimental concept validation was carried out in a prototype of 1 kW with an input voltage between 48 and 96 V and an output voltage of 800 V. The results obtained were coherent, with no significant semiconductor over-voltage and high efficiency was achieved for a wide power range.

Journal ArticleDOI
TL;DR: An adaptive variable-frequency peak current mode control with constant crossover frequency to mitigate the tradeoff between stability and transient response while possessing the variable frequency characteristic to improve light load efficiency is proposed.
Abstract: Flyback converters with universal serial bus power delivery (USB-PD) specification are widely used in low-power adapter application. The wide output voltage range operation of USB-PD makes the loop gain vary under different working conditions. To ensure stability in all working conditions, the loop gain has to be compensated based on the worst case of control-to-output transfer function. However, in other conditions, the crossover frequencies of loop gain are sacrificed, resulting in poor transient responses. This paper proposes an adaptive variable-frequency peak current mode control with constant crossover frequency to mitigate the tradeoff between stability and transient response while possessing the variable frequency characteristic to improve light load efficiency. The adaptive control law is derived from the proposed small-signal model. Experimental and simulation results verify the analysis. The proposed control reduces the output voltage variation at load transient by 43% and 34% at 5 and 20 V output voltage, respectively.