Conventional Full-bridge Converter Research Articles

Modified Two-Channel LLC Resonant Converter With Optimal Efficiency for Wide Input Voltage Applications

A modified two-channel LLC resonant converter with optimal efficiency for wide input voltage applications. The converter has the same voltage gain and power handing ability as conventional full-bridge (FB) resonant converter, but the hardware cost is lower than conventional FB resonant converter, and the operational frequency range is narrower than conventional resonant converter for the same working condition. It has the characteristics of low input impedance at low input voltage, which is used to provide high voltage gain, and high input impedance at high input voltage, which is used to provide low voltage gain, the above characteristics are analyzed and optimized to improve the efficiency for photovoltaic applications where wide voltage gain is require. A 1 kW prototype is developed, the input voltage ranges from 80 V to 200 V, the output voltage and output power are 400 V and 1 kW, the experimental result shows that the full-load efficiency can reach 96.5% over the entire input voltage range, and the peak efficiency can reach 96.9% at full-load state.

On approach to optimize manufacturing of field-effect transistors framework a conventional full-bridge converter to increase their integration rate: On influence mismatch-induced stress

In this paper we introduce an approach to increase density of field-effect transistors framework a conventional full-bridge converter. In the framework of the approach we consider manufacturing the inverter in heterostructure with specific configuration. Several required areas of the heterostructure should be doped by diffusion or ion implantation. After that dopant and radiation defects should by annealed framework optimized scheme. We also consider an approach to decrease value of mismatch-induced stress in the considered heterostructure. We introduce an analytical approach to analyze mass and heat transport in heterostructures during manufacturing of integrated circuits with account mismatch-induced stress.

A Bridgeless Isolated Half-Bridge Converter Based EV Charger With Power Factor Preregulation

Conventional full-bridge and half-bridge (HB) converters are quite popular for front-end power factor preregulation (PFP) in electric vehicle (EV) battery chargers. Discontinuous conduction mode (DCM) operation at high power causes increased oscillation in the circuit. These oscillations increase with parasitic components of circuit. During deep DCM operation, these oscillations are seen to be significant and contribute to harmonic content in the input current. Therefore, a PFP bridgeless isolated HB converter based EV charger with reduced <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> oscillation in DCM is presented in this article. To reduce <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> oscillation, two diodes are used in series with minimum number of magnetic components. The design of proposed charger in DCM is illustrated to facilitate uniform battery current during constant current/constant voltage charging. The inherent advantage of reduced conduction loss with bridgeless topology is achieved. The performance of this isolated HB converter based charger is shown for improved oscillation characteristics and power quality operation at steady state and over a range of varying input voltages.

Design and Implementation of Improved High Step-Down DC-DC Converter for Electric Vehicles

An improved high step-down DC-DC converter for charging the batteries in an electric vehicle application is proposed in this paper. It adopts the topology of the conventional full-bridge converter, which has a coupled inductor current-doubler rectifier as the secondary side of the transformer. In addition, four power switches are driven using a phase-shifting technique. The proposed converter can achieve a high step-down voltage with low-voltage stress on the rectifier diodes. In addition, the coupled inductor current-doubler rectifier of the secondary side can reduce the ripple current and losses of the secondary side to achieve high efficiency. Furthermore, the proposed converter can overcome the drawbacks of the conventional full-bridge converter, such as switching loss caused by high switching frequency, duty-cycle loss, voltage stress, and numerous components, and can increase the efficiency with the soft-switching technique. A 600 W laboratory prototype of the proposed converter was manufactured. The results of the experiments performed with the prototype proved the effectiveness and validated the use of the proposed converter for better charging of electric vehicles.

Analysis of a Wide Voltage Hybrid Soft Switching Converter

A hybrid PWM converter is proposed and investigated to realize the benefits of wide zero-voltage switching (ZVS) operation, wide voltage input operation, and low circulating current for direct current (DC) wind power conversion and solar PV power conversion applications. Compared to the drawbacks of high freewheeling current and hard switching operation of active devices at the lagging-leg of conventional full bridge PWM converter, a three-leg PWM converter is studied to have wide input-voltage operation (120–600 V). For low input-voltage condition (120–270 V), two-leg full bridge converter with lower transformer turns ratio is activated to control load voltage. For high input-voltage case (270–600 V), PWM converter with higher transformer turns ratio is operated to regulate load voltage. The LLC resonant converter is connecting to the lagging-leg switches in order to achieve wide load range of soft switching turn-on operation. The high conduction losses at the freewheeling state on conventional full bridge converter are overcome by connecting the output voltage of resonant converter to the output rectified terminal of full bridge converter. Hence, a 5:1 (600–120 V) hybrid converter is realized to have less circulating current loss, wide input-voltage operation and wide soft switching characteristics. An 800 W prototype is set up and tested to validate the converter effectiveness.

A Three-Phase Triple-Voltage Dual-Active-Bridge Converter for Medium Voltage DC Transformer to Reduce the Number of Submodules

In order to improve the power density of dc transformer (DCT), this article proposes a novel three-phase dual-active-bridge (DAB) dc–dc converter, which possesses triple input voltage of conventional full-bridge DAB converter without increasing the voltage stress of switches. By adopting it as the DCT submodule (SM), the number of SMs in DCT is reduced markedly and power density can be improved. Based on the analysis of operation principle, design procedure, basic control strategy and startup scheme of the proposed three-phase triple-voltage DAB (T2-DAB) converter are presented. Then, the feasibility of proposed converter is verified with simulation and a 2 kW, 600/200 V prototype. Finally, the superiority of the DCT scheme based on proposed T2-DAB converter is verified by a comparison with some existing DAB schemes.

Active Rectification For the Optimal Command of Bidirectional Resonant Wireless Power Transfer Robust to Severe Circuit Parameters Deviations

In this article, a method resorting to active rectification for the optimal control of a bidirectional resonant wireless power transfer system is proposed. Benefiting from a dual active bridge topology and without requiring any additional dc-dc converter, the real and the imaginary parts of the equivalent load impedance are modulated simultaneously and independently, for achieving optimal operating conditions despite circuit parameters deviations. Based on a first harmonic analysis, the methodology and its beneficial impacts against variations in the windings mutual inductance or against mistuned resonant capacitor are presented and illustrated. By an argued discussion, the proposed method extent is enlarged to changes in any circuit parameters. Time-domain simulations of the converters topology and command demonstrates the method effectiveness by achieving the system maximum efficiency. Controllability restrictions preventing the compensation of the most severe parameters variations are highlighted. Associated with the limited voltage producible by conventional full-bridge converters, the latter restrictions are surmounted with success by considering Z-source topologies for the front-end and back-end converters.

Analysis and Implementation of a Phase-Shift Pulse-Width Modulation Converter with Auxiliary Winding Turns

A phase-shift pulse-width modulation converter is studied and investigated for railway vehicle or solar cell power converter applications with wide voltage operation. For railway vehicle applications, input voltage range of dc converters is requested to have 30–40% voltage variation of the nominal input voltage. The nominal input voltages of dc converters on railway vehicles applications may be 37.5 V, 48 V, 72 V, 96 V and 110 V. Therefore, a new dc converter with wide input voltage operation from 25 to 150 V is presented to withstand different nominal input voltage levels such as 37.5–110 V on railway power units. To realize wide input voltage operation, an auxiliary switch and auxiliary transformer windings are used on output side of conventional full-bridge converter to have different voltage gains under different input voltage values. Phase-shift pulse-width modulation is adopted in the developed dc converter to accomplish soft switching operation on power switches. To confirm and validate the practicability of the presented converter, experiments based on a 300 W prototype were provided in this paper.

Resonant Converter with Soft Switching and Wide Voltage Operation

A new DC/DC resonant converter with wide output voltage range operation is presented and studied to have the benefits of low switching losses on active devices and low voltage stresses on power diodes. To overcome serious reverse recovery losses of power diodes on a conventional full-bridge pulse-width modulation converter, the resonant converter is adopted to reduce the switching loss and increase the circuit efficiency. To extend the output voltage range in conventional half-bridge or full-bridge resonant converters, the secondary sides of two diode rectifiers are connected in series to have wide output voltage operation. The proposed converter can be either operated at one-resonant-converter mode for low voltage range or two-resonant-converter mode for high voltage range. Thus, the voltage rating of power diodes is decreased. Experiments with the design example are given to show the circuit performance and validate the theoretical discussion and analysis.

A Three-Level Rectifier Structure With Flying Capacitors for DC–DC Converter in High-Voltage Output Application

In high-voltage output applications, the rectifier diodes in the conventional full-bridge converter have to bear the whole secondary voltage of a transformer. In this paper, a three-level rectifier structure with flying capacitors is proposed for the dc–dc converter. Compared with the conventional dc–dc converter, the converter with the proposed rectifier structure has the following advantages: low-voltage diodes could be used for high-voltage output applications; due to the secondary flying capacitors, there are no voltage spikes on the rectifier diodes even if no snubber circuits are attached; not only can the leading switches realize zero voltage switching (ZVS) as the same as the conventional converters, but also the lagging switches can realize zero current switching in discontinuous-conduction mode and ZVS in continuous-conduction mode; and the rectified voltage has no zero-state voltage, it has been raised to half of the input voltage, so the voltage fluctuation is lower than the conventional converter under the same modulation strategy, and the current ripple of the filter inductor can be reduced by half. The operation principle of the proposed rectifier structure is analyzed in details, and a prototype is fabricated to verify the features of the proposed converter.

ZVS Converter with Full-Bridge and Half-Bridge Circuits: Analysis, Design and Implementation

A new DC/DC converter integrating a full-bridge circuit and a half-bridge pulse-width circuit is studied to realize the advantages of a wide range of zero-voltage switching (ZVS) and less circulating current loss. A half-bridge converter is connected to power switches on the lagging-leg of full-bridge converter to achieve a wider range of ZVS to overcome the disadvantage of narrow ZVS range in conventional full-bridge converter. The output side of half-bridge circuit is linked to the secondary side of the full-bridge converter to decrease the primary circulating current of the full-bridge converter. Therefore, the conduction losses due to the high circulating current in conventional full-bridge converter are reduced. The theoretical analysis is discussed in detail and the effectiveness of the proposed converter is verified by the experimental verifications with a 1440[Formula: see text]W prototype.

Isolated Double Step-Down DC–DC Converter With Improved ZVS Range and No Transformer Saturation Problem

In this paper, an isolated double step-down dc–dc converter with high efficiency and high step-down function is proposed. The proposed converter employs an additional capacitor in the primary side. Compared to the conventional full-bridge converters, the proposed converter has a double step-down feature with reduced voltage stress at the primary side of the transformer. Moreover, voltage stress of three primary-side switches reduces to half of the input voltage and zero voltage switching (ZVS) is naturally achieved for all switches with lower output capacitor energy of the switches. Therefore, the proposed converter requires smaller leakage inductance than the conventional full-bridge converter. Without adding complexity to the hardware and control, the proposed converter inherently prevents transformer saturation problem caused by the dc component of the transformer. A 3-kW experimental prototype is constructed to verify the performance of the proposed converter.

Beijing Converters: Bridge Converters With a Capacitor Added to Reduce Leakage Currents, DC-Bus Voltage Ripples, and Total Capacitance Required

Isolation transformers and bulky electrolytic capacitors are often used in power electronic converters to reduce leakage currents and voltage ripples but this leads to low power density and reduced reliability. In this paper, an auxiliary capacitor is added to the widely used conventional full-bridge converter to provide a path for, and hence significantly reduce, the leakage current. The operation of the full-bridge converter is split into the operation of a half-bridge converter and a dc–dc converter so that the ripple energy can be diverted from the dc-bus capacitor to the auxiliary capacitor. Hence, the dc-bus capacitor can be significantly reduced while maintaining very low voltage ripples on the dc bus because it is only required to filter out switching ripples. The auxiliary capacitor is designed to allow high voltage ripples because its voltage is not supplied to any load. Accordingly, the auxiliary capacitor can also be very small as well. As a result, the total required capacitance becomes very small. The reduction ratio of the total capacitance is significant, which makes it cost-effective to use film capacitors instead of electrolytic capacitors. The proposed converters can be also operated as an inverter without any restriction on power factor because the adopted four switches are all bidirectional in terms of power flow. Experimental results for both rectification and inversion modes are presented to demonstrate the performance of the proposed converter in reducing the ripples, the leakage currents, and the total capacitance needed, with comparison to the conventional bridge converter without the auxiliary capacitor.

Analysis and implementation of wide zero‐voltage switching dual full‐bridge converters

A new full-bridge converter is presented to have the advantages of low conduction loss and wide zero-voltage switching (ZVS) range. The proposed converter includes two dc–dc converters connected in parallel to reduce the current stresses of power components. Each dc–dc converter integrates a phase-shift pulse-width modulation full-bridge circuit and an un-regulated half-bridge circuit sharing the lagging-leg switches in order to reduce the switch counts. The un-regulated half-bridge circuit is adopted to extend the ZVS range of the lagging-leg switches to improve the drawback of the narrow ZVS range in conventional full-bridge converter. Two dc–dc converters share the lagging-leg switches so that the switch counts in the proposed converter are less than the switches in conventional parallel full-bridge converters. The resonant capacitors are used on the primary side of full-bridge converters to reduce the primary current to zero at the freewheeling state. The secondary windings of full-bridge and half-bridge converters are connected in series to generate two positive voltage levels at the secondary rectified voltage. Therefore, the output inductor voltage at the freewheeling state is decreased and the output inductor size is reduced. Finally, the effectiveness of the proposed converter is verified by the experiments.

Analysis and implementation of a three‐level hybrid dc–dc converter with the balanced capacitor voltages

In this study, a three-level hybrid dc/dc converter by integrating the full-bridge circuit, resonant circuit and three-level flying capacitor circuit is presented to achieve the main advantages of low-voltage stress of power devices, low circulating loss, low-voltage ringing on the rectifier diodes and low-output filter inductor for medium-voltage dc-based systems. Two full-bridge circuits are connected in series to effectively reduce the voltage stress of switches. Half-bridge resonant circuit shared the lagging-leg switches of full-bridge circuit is used and operated at fixed switching frequency to extend the zero-voltage switching (ZVS) range from low load to full load. Thus, the drawback of narrow ZVS range in the conventional full-bridge converter is improved. A flying capacitor is adopted to automatically balance input split capacitor voltages in each switching cycle without any additional active components or complexity control scheme. The circulating loss in the full-bridge circuit is reduced to zero by parallel connection of outputs of full-bridge circuit and half-bridge resonant circuits. Finally, the theoretical analysis and performance of the proposed converter are verified by the experiments with a 1.92 kW prototype circuit.

Simple High Efficiency Full-Bridge DC-DC Converter using a Series Resonant Capacitor

This paper presents a simple high efficiency full-bridge DC-DC converter using a series resonant capacitor. The proposed converter achieves the zero voltage switching of the primary switches under a wide range of load conditions and reduces the high circulating current in the freewheeling mode using the leakage resonant inductance and the series resonant capacitor. Thus, the proposed converter overcomes the drawbacks of the conventional full-bridge DC-DC converter and improves its overall system efficiency. Its structure is simplified by using the leakage inductance of the transformer as the resonant inductance and omitting the DC output filter inductance. Also it can operate over a wide range of input voltages. In this paper, the operational principle, analysis and design example are described in detail. Finally, the experimental results from a 650W (24V/27A) prototype are demonstrated to confirm the operation, validity and features of the proposed converter.

비대칭 펄스 폭 변조 방식의 배전류 정류기 회로를 적용한 고효율 풀-브릿지 DC-DC 컨버터

A high-efficiency full-bridge DC-DC converter with a current-doubler rectifier and an asymmetric pulse-width modulation is proposed. Through the asymmetric pulse-width modulation, the proposed converter achieves zero-voltage switching of power switches without the circulating currents. The proposed converter reduces the output current ripple through the current-doubler rectifier. A control strategy is suggested for the proposed converter to charge battery banks. A constant current and constant voltage charging is performed. The proposed converter achieved a higher efficiency compared with the conventional full-bridge DC-DC converter with a phase-shift modulation. The performance of the proposed converter is evaluated by the experimental results for a 1.0 kW prototype circuit.

Performance Improvement of Isolated High Voltage Full Bridge Converter Using Voltage Doubler

The performance of an isolated high voltage full bridge converter is improved using a voltage doubler. In a conventional high voltage full bridge converter, the diode of the transformer secondary voltage undergoes a voltage spike due to the leakage inductance of the transformer and the resonance occurring with the parasitic capacitance of the diode. In addition, in the phase shift control, conduction loss largely increases from the freewheeling mode because of the circulating current. The efficiency of the converter is thus reduced. However, in the proposed converter, the high voltage dual converter consists of a voltage doubler because the circulating current of the converter is reduced to increase efficiency. On the other hand, in the proposed converter, an input current is distributed when using parallel input / serial output and the output voltage can be doubled. However, the voltages in the 2 serial DC links might be unbalanced due to line impedance, passive and active components impedance, and sensor error. Considering these problems, DC injection is performed due to the complementary operations of half bridge inverters as well as the disadvantage of the unbalance in the DC link. Therefore, the serial output of the converter needs to control the balance of the algorithm. In this paper, the performance of the conventional converter is improved and a balance control algorithm is proposed for the proposed converter. Also, the system of the 1.5[kW] PCS is verified through an experiment examining the operation and stability.

High-Efficiency AC-DC Switch-Mode Power Supply Using FullBridge Converter Circuits

This paper presents a high-efficiency AC-DC switch-mode power supply (SMPS) using the full-bridge converter circuits. The proposed converter utilizes three full-bridge converter circuits: two full-bridge diode converter circuits and one full-bridge MOSFET converter circuit. The two full-bridge converters are utilized at the primary AC input and the secondary DC output, respectively, and the full-bridge MOSFET converter is used to convert a DC voltage to a high-frequency AC voltage that is converted to another DC voltage with the transformer and the secondary full-bridge diode converter, which is simply referred to as the full-bridge DC-DC converter. However the conventional full-bridge converter has a limit in its operating duty ratio in normal operation, because it results in more conduction loss in light load operation. Therefore, the proposed converter resolves the drawbacks of the conventional full-bridge converter using a modified full-bridge circuit with a DC blocking capacitor in the primary. Thus, the proposed converter has improved total efficiency and performance. The operation principle of the proposed converter is described in detail, and a design example of a prototype is shown. The good performance of the proposed converter is demonstrated through experimental results of the implemented prototype based on the design example.

A New ZCS-PWM Full-Bridge DC–DC Converter With Simple Auxiliary Circuits

A new soft-switching pulsewidth modulated (PWM) full-bridge converter is proposed in this paper. The outstanding feature of the new converter is that it allows its main power switches to operate with zero current switching (ZCS) and with fewer conduction losses than conventional full-bridge converters. This is achieved by using two very simple active auxiliary circuits-one active, the other passive. The paper presents the new converter and then discusses its operation, steady-state characteristics, and design. Experimental results obtained from a 3 kW converter prototype are presented to validate the converter's performance and the concepts presented in the paper.