Wide ZVS Range Research Articles

Modulated-Coupled-Inductor-Based ISOP Phase-Shifted Full-Bridge Converter With Wide ZVS Range and Reduced Duty-Cycle Loss

Modulated-Coupled-Inductor-Based ISOP Phase-Shifted Full-Bridge Converter With Wide ZVS Range and Reduced Duty-Cycle Loss

Closed-Form Continuous Asymmetrical Hybrid Modulation, Ensuring Wide ZVS Range and Seamless Transients for DAB Converters

Closed-Form Continuous Asymmetrical Hybrid Modulation, Ensuring Wide ZVS Range and Seamless Transients for DAB Converters

Offset Current Modulation Technique for Wide ZVS Range in Dual Active Bridge (DAB) DC-DC Converter

Offset Current Modulation Technique for Wide ZVS Range in Dual Active Bridge (DAB) DC-DC Converter

LLCC Resonant Converter With Wide ZVS Range and Low Voltage and Current Stress

LLCC Resonant Converter With Wide ZVS Range and Low Voltage and Current Stress

Ripple-Free Bidirectional DC–DC Converter With Wide ZVS Range for Battery Charging/Discharging System

A ripple-free bidirectional dc-dc converter (BDC) with wide soft-switching range is proposed for battery charging/discharging application in this paper. On battery side, the current ripple can maintain zero by two-phase interleaving technology in spite of the battery voltage and transfer power variation. Through series connection, high voltage conversion ratio and reduced voltage stresses of switches can be achieved effectively. The built-in transformer technology allows for a small magnetic component size, due to its inherent saturation avoidance. With the proposed control law, the control variables can be decoupled. The duty cycle is fixed by battery side voltage while the transfer power can be regulated monotonously by phase-shift angle. Theoretical derivation illustrates that soft switching can be obtained in all switches by adopting proper parameter design. Furthermore, comparative analysis shows the proposed converter is suitable for battery charging/discharging applications. The experimental verification proves the merits of the proposed converter by a 40-60V/400V 1 kW prototype.

Variable Saturation Inductor-Based Full Bridge Converter With Wide ZVS Range and Reduced Duty Cycle Loss

A phase-shifted full-bridge (PSFB) converter is widely used in various applications due to its soft-switching characteristics. However, one of the recognized shortcomings of the PSFB converter is that it cannot simultaneously have a wide soft switching range and a small secondary-side duty cycle loss. The shortcoming hinders the high frequency and high efficiency of the converter. In this article, the change of the energy demand of the converter on the external series inductor with input voltage and load is analyzed. On this basis, a variable saturation inductor with controllable energy is proposed to meet the energy demand and solve the problem of core heating. The controllable change characteristics of the inductor energy are studied directly instead of the controllable change of the inductance value. By adjusting the inductor energy, the PSFB can not only achieve soft switching under light loads, but also reduce duty cycle loss under heavy loads. Theoretical analysis and experimental verification are carried out on the soft switching and duty cycle loss of the converter. Since the transformer ratio can be increased due to thesmaller duty cycle loss. The efficiency of the converter can be further improved.

Comprehensive Optimization Modulation Scheme of Low Current Level and Wide ZVS Range for Dual Active Bridge Converter With Dead-Zone Control

Due to the contradiction between

Analysis of novel phase-shifted full-bridge converters with wide ZVS range reduced filter requirement

Analysis of novel phase-shifted full-bridge converters with wide ZVS range reduced filter requirement

Secondary Side Cascaded Winding-Coupled Bidirectional Converter With Wide ZVS Range and High Conversion Gain

In this article, a secondary side cascaded bidirectional dc-dc converter (SSC-BDC) is proposed with the winding-coupled structure for the bidirectional operations of power flow, which features high voltage gain, full range of soft switching, low current ripple in low voltage side, and extended duty cycle range. Derived from a current-fed dual active bridge converter, the interleaved buck/boost circuit in the primary side is cascaded with the secondary side of full-bridge circuit through the winding coupled inductor to achieve high voltage gain. The differential voltage is designed to generate the bias current to realize soft switching of the eight power switches within a wide range of load variation. Meanwhile, pulse width modulation (PWM) plus phase-shift modulation is used to eliminate backflow power and increase conversion efficiency. The operation principle, steady-state analysis, and comparison result are presented in detail. Finally, a 1-kW experimental prototype is constructed to verify the feasibility of the SSC-BDC, and the correctness of the theoretical analyses is validated by experimental results.

Leakage Inductor Current Peak Optimization for Dual-Transformer Current-Fed Dual Active Bridge DC–DC Converter With Wide Input and Output Voltage Range

A current-fed dual active bridge dc-dc converter using dual transformers is proposed for the energy storage system and electric vehicles, which is suitable to be used in wide input and wide output voltage range bidirectional power flow applications. Optimized switching pattern and the coupling relationship among all the controlled variables have been explored in order to minimize the leakage inductor current peak and rms value in spite of the load and voltage conversion gain variation, which can reduce the current stress in switches and conduction loss. Furthermore, wide ZVS range can be achieved. The preferred optimized working modes and real-time closed-loop implementation by employing the proposed control strategy are given. The ZVS conditions for each switch are discussed in detail. The turns ratio design is also demonstrated. The effectiveness of the proposed method is verified by the experimental results of a 1-kW prototype.

Three-Level DC-DC Controlled-Source Circuit of Marine Electromagnetic Detection Transmitter

Nowadays, marine electromagnetic method is a geophysical method which can effectively explore natural gas hydrate (NGH) resources. This method acquires seafloor structure and distribution laws of mineral resources by transmitting high-power electromagnetic waves to the seafloor, and its detection depth relies on the intensity of transmitted electromagnetic waves. At present, marine electromagnetic transmitter is not proper for transmission of high-power electromagnetic waves, and therefore, a novel controlled-source circuit of soft switching three-level marine electromagnetic transmitter is proposed in this paper, one step-down winding is added at the secondary side of high-frequency transformer in series connection with a linear inductor, asymmetric phase-shift PWM control is used, and soft switching of controlled-source circuit within the overall power range is realized. A detailed analysis of the operation process and circuit characteristics is given, and finally, a prototype is designed. Experimental results indicate that this circuit is of wide ZVS range and high efficiency, and it meets requirements for deep-sea detection of high-voltage power supply transmitter.

Voltage-Fed Push-Pull PWM Converter Featuring Wide ZVS Range and Low Circulating Loss with Simple Auxiliary Circuit

Voltage-Fed Push-Pull PWM Converter Featuring Wide ZVS Range and Low Circulating Loss with Simple Auxiliary Circuit

Full‐bridge DC/DC converter with wide ZVS range

A soft switching converter is presented with the advantages of wide zero-voltage switching range, low primary conduction loss, less output inductance and power transfer within the whole switching cycle. Half-bridge circuit is connected to the lagging-leg power switches of full-bridge converter to improve the soft switching load range. One positive rectified voltage is generated on the secondary side to reduce the primary current to zero during the freewheeling state. Therefore, the primary conduction loss is reduced. The performance of the proposed converter is verified by the experimental verifications with a 1.92 kW prototype.

Design Guidelines for a Capacitive Wireless Power Transfer System with Input/Output Matching Transformers

A capacitive wireless power transfer (C-WPT) system uses an electric field to transmit power through a physical isolation barrier which forms a pair of ac link capacitors between the metal plates. However, the physical dimension and low dielectric constant of the interface medium severely limit the effective link capacitance to a level comparable to the main switch output capacitance of the transmitting circuit, which thus narrows the soft-switching range in the light load condition. Moreover, by fundamental limit analysis, it can be proved that such a low link capacitance increases operating frequency and capacitor voltage stress in the full load condition. In order to handle these problems, this paper investigates optimal design of double matching transformer networks for C-WPT. Using mathematical analysis with fundamental harmonic approximation, a design guideline is presented to avoid unnecessarily high frequency operation, to suppress the voltage stress on the link capacitors, and to achieve wide ZVS range even with low link capacitance. Simulation and hardware implementation are performed on a 5-W prototype system equipped with a 256-pF link capacitance and a 200-pF switch output capacitance. Results show that the proposed scheme ensures zero-voltage-switching from full load to 10% load, and the switching frequency and the link capacitor voltage stress are kept below 250 kHz and 452 V, respectively, in the full load condition.

Fundamental Duty Modulation of Dual-Active-Bridge Converter for Wide-Range Operation

This paper proposed a modulation scheme for the dual-active-bridge (DAB) converter to reduce rms current in wide-range operating conditions. The operating principle of the proposed fundamental duty modulation (FDM) is formulated based on the fundamental component analysis of the DAB converter. By modulating the PWM signals in the fundamental component domain, the optimal operation is implemented with a simple controller structure not requiring an operating mode classification, offline calculation, or current information. Operating characteristics including rms current level and ZVS characteristics are analyzed to compare loss breakdowns of the proposed scheme to those of recent related works. The proposed FDM achieves high efficiency under wide operation conditions due to reduced conduction level and wide ZVS range. Experimental results are obtained under various voltage gain and load conditions to confirm the operation of the proposed modulation scheme. A thorough experimental comparison with other sophisticated modulation schemes has verified the efficiency improvement of FDM.

Hybrid full‐bridge and LLC converter with wide ZVS range and less output inductance

This study presents a new hybrid full-bridge and LLC converter with the features of low circulating current loss, wide zero voltage switching range and less output inductance for industry power units. The proposed hybrid circuit has two full-bridge converters and one LLC converter with shared lagging-leg switches. Two full-bridge converters, shared the same lagging-leg switches, are operated at phase-shift pulse-width modulation to regulate the output voltage and share the load power. Half-bridge LLC converter is added at the lagging-leg switches to extend the zero voltage switching range of lagging-leg switches from zero to full load. The output voltage of LLC converter is connected to the secondary sides of two full-bridge converters during the freewheeling interval to eliminate the circulating current loss. The rectified voltage of full-bridge converter during the freewheeling stage is positive instead of zero so that the output filter inductance can be reduced. Finally, experiments with a 1440 W prototype circuit converting 380 V input to an output voltage 24 V/60 A are provided to verify the theoretical analysis and effectiveness of the proposed converter.

Hybrid DC–DC converter with high efficiency, wide ZVS range, and less output inductance

SummaryIn this paper, a new soft switching direct current (DC)–DC converter with low circulating current, wide zero voltage switching range, and reduced output inductor is presented for electric vehicle or plug‐in hybrid electric vehicle battery charger application. The proposed high‐frequency link DC–DC converter includes two resonant circuits and one full‐bridge phase‐shift pulse‐width modulation circuit with shared power switches in leading and lagging legs. Series resonant converters are operated at fixed switching frequency to extend the zero voltage switching range of power switches. Passive snubber circuit using one clamp capacitor and two rectifier diodes at the secondary side is adopted to reduce the primary current of full‐bridge converter to zero during the freewheeling interval. Hence, the circulating current on the primary side is eliminated in the proposed converter. In the same time, the voltage across the output inductor is also decreased so that the output inductance can be reduced compared with the output inductance in conventional full‐bridge converter. Finally, experiments are presented for a 1.33‐kW prototype circuit converting 380 V input to an output voltage of 300–420 V/3.5 A for battery charger applications. Copyright © 2015 John Wiley & Sons, Ltd.