Showing papers on "Forward converter published in 2020"

A Reconfigurable Three-Port DC–DC Converter for Integrated PV-Battery System

Abstract: In this article, a new nonisolated three-port dc–dc converter to integrate a battery storage with a photovoltaic (PV) module is proposed for off-grid solar-power applications. The proposed converter can be used to integrate the PV module with a backup battery to minimize the impacts of renewable-energy intermittency and unpredictable load demand. The proposed converter is reconfigurable and able to operate as a conventional boost converter, a buck-boost converter, or a forward converter in different modes to support several power flow combinations and achieve power conditioning and regulation among the PV module, battery, and output port, simultaneously. Nevertheless, the power stage only consists of two switches, one coupled inductor, one diode, and two capacitors. A high-voltage conversion ratio is achieved by using a coupled inductor and by combining the PV module and the battery in series. Experimental results of the proposed converter operating in the steady state and during transitions between different modes are reported.

A 12- or 48-V Input, 0.9-V Output Active-Clamp Forward Converter Power Block for Servers and Datacenters

Abstract: DC-to-DC power supplies are critical components for processors in high performance computing and datacenter servers. Conversion from an intermediate bus voltage (e.g., 12 or 48 V) to the core voltage (∼0.9 V) of processors must be efficient, compact, and cost effective. This paper proposes two versions of active-clamp forward converter (ACFC) power blocks to supply core voltage from either 12 or 48 V intermediate bus voltage. The ACFC power block can be individually tested prior to assembly and vertically soldered onto the motherboard to fit in a standard 1U server. A low loss, compact planar transformer is designed into the ACFC power block printed circuit board (PCB). A custom, standing slab inductor not only provides high inductance and high saturation current but also helps to mechanically support the power block. A one-piece copper winding connects the transformer to the inductor, thereby reducing the dc loss in the current path. Thorough analysis is performed to model the conversion loss of the proposed power block. Experimental results show a peak efficiency of 90.4% (12 V input) and 89.5% (48 V input) with 0.9-V output.

An Active and Passive Hybrid Battery Equalization Strategy Used in Group and between Groups

Abstract: Active battery equalization and passive battery equalization are two important methods which can solve the inconsistency of battery cells in lithium battery groups. In this paper, a new hybrid battery equalization strategy combinfigureing the active equalizing method with a passive equalizing method is proposed. Among them, the implementation of the active equalizing method uses the bidirectional Flyback converter and Forward converter. This hybrid equalizing strategy adopts the concept of hierarchical equilibrium: it can be divided into two layers, the top layer is the equalization between groups, and the bottom layer is the equalization of group. There are three active equilibrium strategies and one passive equilibrium strategy. For verification purposes, a series of experiments were conducted in MATLAB 2018b/Simulink platform. The simulation and experiment results show that this hybrid battery equalizing method is efficient and feasible.

18.6 A 92.8%-Peak-Efficiency 60A 48V-to-1V 3-Level Half-Bridge DC-DC Converter with Balanced Voltage on a Flying Capacitor

Abstract: Demand for DC-DC voltage conversion from a 48V input has been on the rise due to proliferation of server and automotive applications with a 48V intermediate bus and 48V batteries, respectively. Compared to a 12V, the 48V architecture reduces the power loss thanks to the low distribution losses in the power delivery network. However, improving efficiency is a major challenge in the design of a 48V point-of-load (PoL) DC-DC converter due to the high step-down ratio and high output current. To improve conversion efficiency, several 48V PoL converters implemented with high-quality GaN transistors have been proposed [1], [3]. However, the non-isolated hybrid converter in [1] shows a moderate peak efficiency of 90.9% and requires a large number of switches and passive elements. The isolated converter in [2] shows high efficiency and maximum output current of 80A, requiring a high conversion-ratio planar transformer of 40:1, many switches, and a complicated controller, but offers a limited conversion range. In addition, the GaN transistor suffers from reliability issues [4]. Although an active-clamp forward converter in [5] is implemented with MOSFETs, the peak efficiency is limited to 89.5%. A half-bridge (HB) DC-DC converter with a current-doubler rectifier in [3] is a well-known architecture for high step-down ratio and high output current applications. However, the switching loss in the primary-side HB topology limits the overall efficiency. This paper presents a high-efficiency 3-level HB DC-DC converter with a current-doubler rectifier for power conversion from a 48-to-60V input to an output ranging from 0.5V to 1V.

Double-Ended Active-Clamp Forward Converter With Low DC Offset Current of Transformer

Abstract: The double-ended (DE) active-clamp forward (ACF) converter is one of the attractive dc–dc converters for the power supply of digital devices due to a simple structure and zero voltage switching (ZVS) capability of primary switches. However, due to a dc offset current of transformer, the size and core loss of transformer are increased. In this paper, a new DE-ACF converter having an additional switch and a diode is proposed to achieve a low dc offset current of transformer by charging a clamp capacitor additionally during a turn- off interval between main switches. Thus, the transformer size can be reduced in the proposed converter. Furthermore, since the output inductor current ripple is reduced, the primary and secondary conduction losses can be decreased under medium and heavy loads. As a result, the proposed converter can have higher efficiency than conventional DE-ACF converter. The validity of the proposed converter is confirmed by experimental results from a prototype with 400 V nominal input voltage and 400 W (12 V/33.33 A) output.

Multivariable Unconstrained Pattern Search Method for Optimizing Digital PID Controllers Applied to Isolated Forward Converter

Abstract: Most of the traditional PID tuning methods are heuristic in nature. The heuristic approach-based tuned PID controllers show only nominal performance. In addition, in the case of a digital redesign approach, mapping of the heuristically-designed continuous-time PID controllers into discrete-time PID controllers and in case of the direct digital design approach, mapping of the continuous-time plant (forward converter) into the discrete-time plant, results in frequency distortion (or warping). Besides this, nonlinear elements such as ADC and DAC, and delay in the digital control loop deteriorate the control performance. There is a need to tune conventionally-designed digital controllers to enhance performance. This paper proposes optimized discrete-time PID controllers for a forward DC–DC converter operating in continuous conduction mode (CCM). The considered conventional digital PID controllers designed on the basis of the digital redesign and direct digital approaches are tuned by one of the multivariable unconstrained pattern search methods named Hooke–Jeeves (H–J) search method to ensure excellent output voltage regulation performance against the changes in input voltage and load current. Numerical results show that the H–J-based optimized PID compensated forward converter system shows tremendous improvement in performance compared to its unoptimized counterpart and simulated annealing (SA)-based compensated system, thus justifying the applicability of the H–J method for enhancing the performance.

High Performance Gate-Driver Power Supply for Multilevel-based 1500 V Converters

Abstract: Power semiconductor devices require advanced pulse-width gate-driver capability to successfully convert power for high performance operation. In this paper, a simplified forward isolated converter topology with an integrated planar transformer is proposed, which eliminates the need of output filter inductor while rearranging the clamp circuit for reduced components ratings and voltage stress in a cost-effective solution. The proposed single-switch forward converter topology employs switch protection and transformer core demagnetization with Zener diode voltage-clamped circuit. Through the converter analysis, the switching frequency has been selected in relationship to the transformer inductance and the equivalent circuit capacitance for the benefit of soft-switching devices transitions. The converter features multiple isolated secondaries necessary for independent gate-driver voltage supplies in multi-level converters. Specifically, the proposed converter provides voltage supplies for a gate-driver power devices pair, such as half-bridge SiC devices. The integrated solution reduces the total number of gate-drivers transformers necessary in multilevel-based 1500V converters. The simulation and experimental results are obtained from a gate-drive application platform to demonstrate the validity of the proposed isolated dc-dc converter design with integrated planar transformer.

An Interleaved Active-Clamp Forward Converter Modified for Reduced Primary Conduction Loss Without Additional Components

Abstract: This paper proposes an interleaved active-clamp forward (IACF) converter modified for high efficiency without any additional component. To employ high input voltage, the components on one active-clamp forward module are re-arranged from the conventional IACF converter. The proposed converter can significantly reduce the primary conduction loss with large turns-ratio of the transformer due to the higher input voltage of the modified module and the expanded duty ratio at the nominal input voltage. In addition, unlike the existing approaches, the power density is not affected because there is no additional component. Finally, the proposed converter is validated experimentally using a prototype converter with 36–72 V dc input and 480 W (12 V dc/40 A) output.

High-Efficiency Three-Phase Single-Stage Isolated Flyback-Based PFC Converter With a Novel Clamping Circuit

Abstract: This article analyzes a three-phase single-stage isolated flyback-based power factor correction converter and presents a novel clamping circuit to capture the transformers leakage inductance energy. The converter unity power factor operation is obtained by using the inherent resistance property of discontinuous conduction mode. Thus, the input current shaping circuit is eliminated and resulted in a single-loop control system. Therefore, the converter control circuit requires only one sensor, which decreases the system cost, and also increases the system robustness to high-frequency noise. With the proposed clamping circuit, the transformers leakage inductance energy is successfully captured in clamping capacitor, and thereby, it is fed to the dc load by using an auxiliary two-switch forward converter which enhanced the overall operating efficiency of a converter. The converter detailed steady-state operation and the design considerations are presented. Each power component voltage stress expressions are derived to simplify the converter design, and the converter small-signal model is presented to help the controller design. The novelty and performance of the converter is verified by both simulation and experimentation.

A Zero-Voltage and Zero-Current Switching Interleaved Two-Switch Forward Converter With Passive Auxiliary Resonant Circuit

Abstract: This article presents an interleaved two-switch forward dc/dc converter with zero-voltage and zero-current switching, which adopts a coupled inductor and a snubber capacitor. The proposed converter can realize soft operation for main power switches by using the coupled inductor, snubber capacitance, the leading switches' parallel capacitances, and the transformer leakage inductance. Compared with the initial converter that uses a coupled inductor, during the freewheeling stage, the proposed converter has significant performance in reducing the primary circulating current that flows through the power elements. More importantly, the proposed converter can eliminate the problems in the rectification diodes such as voltage stress, parasitic ringing, and reverse recovery. Based on the equivalent circuits in different operation modes, the operation principle and the soft-switching requirement of the converter are discussed. Besides, the design criteria for the key parameter are given in this article. The practical effectiveness of the proposed converter was validated by the simulation results and experimental results of prototype using the power mosfet.

Closed-Loop Gate Drive for Single-Ended Forward Converter to Reduce Conducted EMI

Abstract: Forward DC/DC converters are widely used in low and medium power circuits that are widely used in the aerospace and navigation fields Power converters are usually sources of electromagnetic interference (EMI), which is due to their higher voltage and current transients The traditional method is to add expensive filters on the primary side or the secondary side, but its disadvantages are high cost and poor adjustability Based on the principle that the greater the number of derivations of voltage transients, the lower the high frequency electromagnetic interference contained in this voltage, a signal containing small high-frequency noise that is suitable for the hardware circuit as a reference signal is selected, and a closed-loop gate drive method is used in this paper, which attenuate the conducted EMI noise in the input bus of the forward DC/DC converter The reference signal shapes the output signal to achieve the purpose of suppressing electromagnetic interference through the closed loop circuit The advantages of this method are making the output highly adjustable, reducing hardware size and weight and lower cost compared with filter method Compared with the method of controlling current to reduce electromagnetic interference, the proposed method is easier to implement Firstly, the relationship between the derivative order of voltage transient and electromagnetic interference is introduced Secondly, the experimental principle of single-ended forward circuit controlled by closed loop is introduced Simulation and experimental results show that the proposed method can achieve voltage shaping and suppression of voltage overshoot effectively Compared with the traditional hard-switching control method, the proposed method can make the high-frequency components of the drain-source voltage of the primary-side MOS transistor and the secondary-side output voltage have a greater attenuation

Zero-current transition single-ended forward converter

Abstract: In this study, a novel zero-current transition (ZCT) auxiliary circuit is applied to pulse-width modulation single-ended forward converter (PWM SEFC). The proposed ZCT circuit has achieved the power switch zero-current switching (ZCS) turn-on; the power switch ZCT turn-off; the auxiliary switch ZCS and zero-voltage switching turn on/off and soft-switching conditions for output diodes. Moreover, the transformer core reset is prepared by the ZCT circuit and tertiary winding is removed. The novel ZCT-PWM SEFC is analysed at a steady-state for operating under continuous conduction mode. The proposed ZCT circuit is designed, and the experimental result from a 200 W-100 KHz prototype is prepared to confirm the theoretical analysis.

Forward converter-based distributed global maximum power point tracking in partial shading conditions

Abstract: Maximum power point tracking (MPPT) is an essential part of a photovoltaic (PV) power generation systems to obtain the possible biggest efficiency. In partial shading conditions (PSCs), distributed MPPT strategy is used to eliminate mismatching cases between PV modules and load. In this study, forward converter-based distributed MPPT approach is presented for small power module-level and submodule-level MPPT applications. First, operation principles of a forward converter are explained for an MPPT application. Then, performance of a forward converter is evaluated by perturb and observe (P&O) algorithm for module-level and submodule-level MPPT systems in MATLAB/Simulink. Simulation results show that in module-level MPPT technique, forward converter cannot track global maximum power point (MPP) in some PSCs. On the other hand, submodule-level MPPT guarantees global MPPT (GMPPT). Average tracking efficiencies are calculated as 71.24% and 95.34% for module-level and submodule-level MPPT, respectively. That is, submodule-level MPPT outperforms module-level MPPT. On the other hand, submodule-level MPPT is more expensive solution since hardware requirements are very high compared with the module-level MPPT strategy.

An Integrated Programmable Gate Timing Control and Gate Driver Chip for A 48V-to-0.75V Active-Clamp Forward Converter Power Block

Abstract: This paper presents an integrated programmable gate timing control and primary gate driver chip for an active-clamp forward converter (ACFC) Power Block for data center applications. The ACFC Power Block converts 48 V intermediate bus voltage to processor core voltage on a motherboard with high power density. To improve the overall efficiency and reduce the system form factor, the gate timing control function and gate driver with a high voltage level shifter are integrated on a gate driver chip. These features in the gate driver chip enable the Power Block to optimize the timing of switching transistors and therefore achieve optimum efficiency. The silicon chip is fabricated in a 0.13 μm BCD process. Initial hardware operates at 48 V input and 0.75 V output voltages. Full gate timing control functions have been verified by measurement. An electrical model of this converter shows over 90% efficiency at 130 A.

Operation of Solar PV with PEM Fuel Cell for Remote Hybrid Microgrid

Abstract: The hybrid microgrid gives the platform to use different renewable energy sources productively. This paper shows the hybrid operation of Solar PV and proton exchange membrane(PEM) fuel cell to supply remote hybrid microgrid. The hybrid microgrid can work as smart grid by using intelligent power management control for controlling numbers of small renewable energy sources with fuel storage. The stored hydrogen can be used with hydrogen based electric vehicles. This hybrid microgrid consists of two different grids; AC and DC. The highly efficient PEM-FC and Solar PV falls under green energy sources with almost nonhazardous towards environment with life of almost 15-20 years. The fuzzy logic is used to control flow rate of hydrogen and oxygen to PEM-FC likewise, the two converter are use which are DC-DC and DC-AC. The perturb and observe MPPT technique is used with Solar PV and boost converter is used with PEM-FC. The DC-DC forward converter is used to supply DC grid which is 120V and IGBT based 6 pulse inverter used to supply in AC grid which is 3-Phase V RMS 208V, 60Hz. The proposed model is simulate using MATLAB SIMULINK software.

Design of high frequency transformers in different shape of core using matlab program

Abstract: This paper deals with the design, simulation and implementation of the high-frequency transformer for a push-pull converter. It also includes transformer design and simulation for two switches, two outputs forward converter. Design these transformers by building a program, this program is designed in MATLAB software using a graphical user interface (GUI). The program is aimed to reduce the efforts and reduce the time compare with the manual design which takes time and effort. This paper provided the shape and geometry of the core that can influence the efficiency of the converter by designing these transformers in two types of core. The design results were validated by simulation in power simulation software (PSIM), and compare the results of simulation and design.

An Active-Clamp Forward Inverter Featuring Soft Switching and Electrical Isolation

Abstract: Traditional photovoltaic (PV) grid-connection inverters with sinusoidal pulse-width modulation (SPWM) control suffer the problem of buck-typed conversion Additional line-frequency transformers or boost converters are required to step-up output voltage, leading to low system efficiency and high circuit complexity Therefore, many flyback inverters with electrical isolation have been proposed by adopting a flyback converter to generate a rectified sine wave, and then connecting with a bridge unfolder to control polarity However, all energy of a flyback inverter must be temporarily stored in the magnetizing inductor of transformer so that the efficiency and the out power are limited This paper presents a high-efficiency active-clamp forward inverter with the features of zero-voltage switching (ZVS) and electrical isolation The proposed inverter circuit is formed by adopting a forward converter to generate a rectified sine wave, and combining with the active-clamp circuit to reset the residual magnetic flux of the transformer Due to the boost capability of the transformer, this inverter is suitable for the PV grid-connection power systems with wide input-voltage variation The operation principles at steady-state are analyzed, and the mathematical equations for circuit design are conducted Finally, a laboratory prototype is built as an illustration example according to proper analysis and design Based on the experimental results, the feasibility and satisfactory performance of the proposed inverter circuit are verified

A 48V-to-1V Buck-Assisted Active-Clamp Forward Converter with Reduced Voltage Stress for Datacenter Applications

Abstract: This paper presents a buck-assisted, active-clamp forward (ACF) converter that achieves direct 48V-to-1V DC-DC conversion for datacenter applications. To mitigate high voltage stresses on semiconductor power switches, the converter employs a buck-assisted architecture with repositioned active-clamp mechanism, which enhances system reliability effectively without adding silicon overhead. In addition, the proposed topology only requires small leakage inductance to achieve zero-voltage switching (ZVS) in the primary side stage, decreasing switching power loss greatly. In the meantime, the switching loss in the secondary side stage is inherently reduced since the current commutation speed is improved due to small leakage inductance. To validate this design, the power stages in the primary side and the secondary side are implemented using LDMOS FETs in an 0.18μm BCD process and gallium nitride (GaN) FETs, respectively. The fully-transistor based simulation results demonstrate that the proposed converter reduces the voltage stress by 25% and requires 2 times less leakage inductance for ZVS compared to conventional ACF converter.

Modeling of high-side active clamp forward converter with resistive parasitics

Abstract: The purpose of this paper is to derive the small-signal/canonical model derivation of the high-side active clamp forward converter (ACFC) with diode rectification for ideal and with resistive parasitics. It also covers the analysis of ACFC small-signal model with resistive parasitics using computer-aided modeling software Personal Computer Simulation Program with Integrated Circuit Emphasis (PSPICE) 16.6. The effects of variation of system parameters on the ACFC’s state transfer functions and operations have been highlighted in this paper.,The large-signal model and small-signal model of the ACFC with diode rectification has been derived using AC small-signal modeling approach.,The operating point of the converter changes with the consideration of resistive parasitics compared with the ideal case. The response obtained from the hardware matches with the time domain response of the averaged model and switch model developed in PSPICE.,This paper limits the study of ACFC small-signal behavior by using computer-aided design software PSPICE. The dead time of the converter is not considered because it is negligible when compared with the on and off time. The leakage inductance which plays a role in zero voltage switching of the ACFC switches is neglected in the analysis as it is very small compared to the magnetizing inductance. The switching losses are not considered in the modeling.,The mathematical computation of deriving the system transfer functions from canonical model is complex and time consuming.,The modeling with resistive parasitics improves the effectiveness of the equivalent model. Also, the analysis with computer-aided modeling software PSPICE gives reliable results in less time.

A Three-Phase Isolated Rectifier using Current Unfolding and Active Damping Methods

Abstract: This paper discusses a three-phase isolated rectifier with integrated buck functionality, derived from an unfolding three-phase inverter and a 7-level forward converter. Its operating principle is based on current shaping and unfolding methods. The circuit consists of 10 diodes, 3 low-frequency bidirectional switches and 8 high-frequency switches. It operates as a current source converter and requires only 3 filter capacitors at the ac input and a dc filter inductor at the dc output. Parasitic inductances from the ac grid enable direct connection to the utility. This paper discusses the basic operating principle and control method of the proposed inverter. It proposes a new unsymmetrical modulation method that can reduce switching frequency while maintaining the accuracy of current sampling. Also, an active damping method is used to overcome intrinsic oscillation due to unfolding operation. Finally, experimental verification is carried out to confirm stable operation of the proposed three-phase isolated rectifier.

An Interleaved Dual Double-Ended Forward Converter Based LED Driver for DC Lighting Grids

Abstract: The article offers a dual double-ended forward converter based Light Emitting Diode (LED) driver for DC grid lighting applications The converter has two complete double-ended forward converter modules operated in interleaved mode This converter is operated at 100 kHz The proposed configuration of interleaved dual DC-DC double ended forward converters provides many advantages compared to conventional double-ended forward converter such as very less current ripple, high efficiency and faster dynamics Further using interleaving, device stress can be lowered and result in increased efficiency This paper explores the use of dc micro-grid powered LED lighting It can be used for residential, street lighting purposes The detailed circuit operation, simulation results of the proposed circuit for 8125 W are presented

Space borne forward converter with discrete LDO to power OCXO

Abstract: The object of paper is to design & development of consistent, robust space grade power supply for space application of OCXO & launch vehicle with wide input voltage range. The nominal input voltage of space application is 28V DC bus. The end use of power supply will be for supplying various OCXO. The Satellite is using power supply unit (PSU) which provides single output. This converter is designed with Forward Converter Topology & discrete LDO is used to meet the required specifications. The power supply has been designed by Voltage mode with the feed forward control method has been implemented to offer superior CS101 performance. This converter delivers the output of 9W for the input voltage of 24V-36V at a switching frequency of 150 kHz.

Hardware Implementation of Forward Converter with Active Clamp Reset Technique

Abstract: In Defense and Aerospace applications, particularly at the lower input voltage the required duty cycle to regulate the output voltage is greater than 50%. In order to overcome this problem in traditional forward converter, many a times active clamp reset technique is used to reset the power transformer. Using active clamp reset technique duty cycle greater than 50% and lower voltage stress across the switching device is obtained and there will be an improved efficiency of the converter. Therefore a high switching frequency DC to DC converter is necessary in miniaturizing power supply. Motivated by these requirements, the project work is undertaken. In this paper Forward converter with active clamp and different practical aspects of the proposed converter are discussed with the hardware results.

High Efficiency Asymmetric Dual Active Clamp Forward Converter with Phase-Shift Control for Small Conduction Loss

Abstract: In this paper, an asymmetric dual active clamp forward (ADACF) converter for reducing the sizeable primary conduction loss is proposed By changing the position of one of two ACF cells and by adding the secondary winding of one transformer, the high DC voltage gain can be achieved Furthermore, the phase-shift control adjusts the overlapping duty with the main switches turned on at the same time so that the voltage gain can also be increased Due to the high voltage gain for the above reasons, the large turns ratio of transformers can be designed, and the proposed converter can improve high efficiency by reducing the large primary conduction loss without additional semiconductor devices and complex circuits To verify the proposed converter, 36-72 V DC input voltage and 480 W (12 V DC /40 A) output prototype has been implemented

Design and implementation of multiple output forward converter with Mag-amp and LDO as post regulators for space application

Abstract: Linear power supplies are commonly used power supplies for many applications. They have some drawbacks such as low efficiency, difficulty in thermal management and also in regulation of the output voltage. Some of these drawbacks can be overcome by Switch Mode Power Supplies (SMPS). One of the best-suited applications of SMPS is for space applications that require power supplies which are lighter, smaller, more efficient and highly reliable. Multiple-output DC-DC converters are an important topology of SMPS that can be used for space applications. But, in multiple output converters usually, only the master output is regulated and the other outputs are left unregulated and this can result in cross-regulation. In this paper, post regulators such as Magnetic amplifiers (Mag-amp) and Low DropOut regulator (LDO) are proposed to regulate each output and also to improve load regulation. In addition to this, the input voltage feed-forward control technique is proposed to control the duty cycle of the switch, which is dynamically faster and provides better line regulation when compared to the voltage feedback controller. Besides, over current protection circuit for the converter is discussed in detail. Keywords: Cross regulation effect, Mag-amp and LDO, multiple output forward converter, output over current protection, voltage feed forward control.

An Efficient DC-Grid Based Half-Bridge LED Driver

Abstract: An Efficient Light-emitting-Diode (LED) Driver circuit for DC-grid applications is proposed with Dimming control. The circuit consists of half bridge series resonant converter(SRC) whose input is double ended forward converter’s (DEFC) output in series with DC-grid voltage. The loss of power conversion can be decreased by processing partial amount of power for LED current regulation. The proposed driver having other advantages, including zero voltage switching of half-bridge inverter circuit, fixed switching frequency and higher efficiency. Double pulse width modulation (DPWM) is used for LED dimming control.

LCD clamping single-tube forward converter and electronic equipment

Abstract: The invention relates to an LCD clamping single-tube forward converter and electronic equipment. The LCD clamping single-tube forward converter comprises a forward transformer, a one-way switching circuit and a clamping magnetic reset circuit, wherein the clamping magnetic reset circuit comprises a coupling capacitor, a first diode and a flyback transformer, the negative electrode of the first diode is connected with the positive electrode of a preset power supply, the positive electrode of the first diode is connected with the first end of a primary winding of the flyback transformer and is connected with the second end of a primary winding of the forward transformer through the coupling capacitor, the second end of the primary winding of the flyback transformer is connected with the negative electrode of the preset power supply, and a secondary winding of the flyback transformer is used for connecting a load. According to the invention, the effective utilization of magnetic reset energy of the forward transformer can be realized, and the reverse impact current interference to the input power supply end is eliminated. The secondary side of the forward transformer outputs to the load during the conduction period of the one-way switching circuit, so that the output voltage ripple of the converter is small, the filtering parameter is small, and the voltage stabilization regulation and modular design are easy.

A New Single-Switch ZCS Flyback-Forward Converter with High Power Density

Abstract: In this paper, a new zero current switching flyback-forward DC-DC converter is proposed. In the proposed converter to provide soft switching condition, an auxiliary circuit without any additional s...