Soft-switching DC-DC Power Converter Research Articles

High-Frequency Soft-Switching PWM DC-DC Converter with Active Output Rectifier Operating as a Current Source for Arc Welding Applications

This paper introduces a high-frequency soft-switching pulse-width modulation DC-DC power converter with secondary active rectifier tested as a DC current source for arc welding applications. The soft-switching DC-DC converter consists of a high-frequency full-bridge inverter, high-frequency power transformer, and a controlled output rectifier with new secondary energy recovery turn-off snubber. Circulating currents in the converter are reduced by using active rectifier, and RMS values of the currents in primary and secondary switches are decreased by utilizing a novel control algorithm. The experimental results of a 4.5 kW DC-DC converter working at switching frequency of 100 kHz are presented.

A high-efficiency DC-DC converter with LC resonant in the load-side of HFT and voltage doubler for solar PV systems

This paper presents the implementation of a prototype phase-shift soft-switching full-bridge PWM DC-DC power converter isolated by a high-frequency transformer (HFT). This circuit topology is based on a new concept of series resonant principle in the secondary side. The step-up HFT and the voltage doubler rectifier make this circuit suitable for low-voltage renewable sources such as fuel cell or PV applications. Meanwhile, all semiconductor switches can achieve zero-voltage soft-switching (ZVS) with the assistance of transformer leakage inductances and lossless capacitive snubbers. The new contribution of this work is that the passive semiconductor switches (diodes) on the secondary side can also perform ZVS and zero-current switching (ZCS) transitions with the assistance of voltage doubler capacitance. The theory of operation and the experimental setup of the proposed circuit with a rated output of 5 kW are presented and discussed. A comparison between simulation and experimental results is explored and illustrated.

A high-efficiency DC-DC converter with LC resonant in the load-side of HFT and voltage doubler for solar PV systems

This paper presents the implementation of a prototype phase-shift soft-switching full-bridge PWM DC-DC power converter isolated by a high-frequency transformer (HFT). This circuit topology is based on a new concept of series resonant principle in the secondary side. The step-up HFT and the voltage doubler rectifier make this circuit suitable for low-voltage renewable sources such as fuel cell or PV applications. Meanwhile, all semiconductor switches can achieve zero-voltage soft-switching (ZVS) with the assistance of transformer leakage inductances and lossless capacitive snubbers. The new contribution of this work is that the passive semiconductor switches (diodes) on the secondary side can also perform ZVS and zero-current switching (ZCS) transitions with the assistance of voltage doubler capacitance. The theory of operation and the experimental setup of the proposed circuit with a rated output of 5 kW are presented and discussed. A comparison between simulation and experimental results is explored and illustrated.

A Novel type of High-Frequency Transformer Linked Soft-Switching PWM DC-DC Power Converter for Large Current Applications

This paper presents a new circuit topology of DC busline switch and snubbing capacitor-assisted full-bridge soft-switching PWM inverter type DC-DC power converter with a high frequency link for low voltage large current applications as DC feeding systems, telecommunication power plants, automotive DC bus converters, plasma generator, electro plating plants, fuel cell interfaced power conditioner and arc welding power supplies. The proposed power converter circuit is based upon a voltage source-fed H type full-bridge high frequency PWM inverter with a high frequency transformer link. The conventional type high frequency inverter circuit is modified by adding a single power semiconductor switching device in series with DC rail and snubbing lossless capacitor in parallel with the inverter bridge legs. All the active power switches in the full-bridge inverter arms and DC busline can achieve ZVS/ZVT turn-off and ZCS turn-on commutation operation. Therefore, the total switching losses at turn-off and turn-on switching transitions of these power semiconductor devices can be reduced even in the high switching frequency bands ranging from 20 kHz to 100 kHz. The switching frequency of this DC-DC power converter using IGBT power modules is selected to be 60 kHz. It is proved experimentally by the power loss analysis that the more the switching frequency increases, the more the proposed DC-DC converter can achieve high performance, lighter in weight, lower power losses and miniaturization in size as compared to the conventional hard switching one. The principle of operation, operation modes, practical and inherent effectiveness of this novel DC-DC power converter topology is proved for a low voltage and large current DC-DC power supplies of arc welder applications in industry.

Tapped-inductor filter assisted soft-switching PWM DC-DC power converter

A novel high-frequency transformer linked full-bridge type soft-switching phase-shift pulsewidth modulated (PWM) controlled dc-dc power converter is presented, which can be used as a power conditioner for small-scale photovoltaic and fuel cell power generation systems as well as isolated boost dc-dc power converter for automotive ac power supply. In these applications with low-voltage large-current sources, the full-bridge circuit is the most attractive topology due to the possibility of using low-voltage high-performance metal-oxide-semiconductor field-effect transistor (MOSFET) and achieving high efficiency of the dc-dc power converter. A tapped-inductor filter including the freewheeling diode is newly implemented in the output stage of the full-bridge phase-shift PWM dc-dc converter to achieve soft-switching operation for the wide load variation range. Moreover, in the proposed converter circuit, the circulating current is effectively minimized without using additional resonant circuit and auxiliary power switching devices. The practical effectiveness of the proposed soft-switching dc-dc power converter was verified in laboratory level experiment with 1 kW 100 kHz breadboard setup using power MOSFETs. Actual efficiency of 94-97% was obtained for the wide duty cycle and load variation ranges.

High-frequency flyback-type soft-switching PWM DC-DC power converter with energy recovery transformer and auxiliary passive lossless snubbers

A two-switch high-frequency flyback-type zero voltage soft-switching PWM DC-DC power converter for use in auxilary power supplies is proposed. Its basic building block is composed of two active power switches and a flyback high frequency transformer. In addition, two passive lossless snubbers with power regeneration loops for energy recovery that consist of a three-turn auxiliary high frequency transformer, auxiliary capacitors and diodes, are introduced to achieve zero voltage soft switching in the full range of light to full load conditions. The power converter has the advantages of a low cost circuit configuration, a simple control scheme and a high efficiency.The converter's operating principle is described and to in order determine circuit parameters, some practical design considerations are discussed. The effectiveness of the proposed power converter is evaluated and is compared to a hard-switching PWM DC-DC converter. The comparative electromagnetic conductive noise characteristics of both DC-DC power converter circuits are also investigated.

Novel soft-commutation DC–DC power converter with high-frequency transformer secondary side phase-shifted PWM active rectifier

This paper presents a novel circuit topology of the voltage source type zero voltage soft-switching (ZVS) full bridge DC-DC power converter with an isolated high-frequency transformer, which incorporates zero-current soft-switching (ZCS) phase-shifted (PS)-PWM active power switches in series with diodes of two bridge arms of a full-bridge rectifier on the high-frequency transformer secondary side. This high-frequency linked DC-DC power converter can achieve ZVS for noncontrolled active power switches on the primary side of the transformer and ZCS for PS-PWM active switches on the secondary side of the transformer under wide load variations as well as a wide PS-PWM regulation range. The switching power losses and conduction power losses of the active devices of the proposed DC-DC converter can be considerably reduced. The proposed DC-DC converter blocks circulating current flowing through the semiconductor switching devices on the transformer primary side as compared to the lossless snubbing capacitor and transformer leakage and magnetising inductor-assisted soft-switching full-bridge DC-DC converter with ZVS PS-PWM scheme on the transformer primary side. The steady-state operating principles of the proposed DC-DC converter are evaluated and discussed, based on the simulation and experimental results obtained from a 2 kW-40 kHz breadboard set-up using IGBTs.

高周波絶縁形ソフトスイッチング位相シフトPWM制御DC-DCコンバータの循環電流低減による効率改善

高周波絶縁形ソフトスイッチング位相シフトPWM制御DC-DCコンバータの循環電流低減による効率改善

Double two-switch forward transformer linked soft-switching PWM DC–DC power converter using IGBTs

A double two-switch forward type high-frequency transformer linked zero-voltage and zero-current mode soft-switching (ZVZCS) pulse width modulation (PWM) DC-DC power converter using IGBTs is presented. A new circuit configuration of the isolated type PWM softly switching converter is proposed to reduce idling and circulating currents in the main circuit without using complex additional active auxiliary resonant snubber circuits and power semiconductor devices, and to decrease the peak voltage across power devices, and their peak current stresses. This soft-switching PWM DC-DC power converter has the unique advantages of less power circuit components and power semiconductor devices, high power conversion efficiency, constant frequency duty cycle control scheme, cost-effective and stable soft-switching operating range under wide load variations for high power applications. The basic operating principle of the soft-switching power converter treated here is illustrated using periodic steady-state circuit analysis for each mode equivalent circuit. The effectiveness of the proposed soft-switching DC-DC power converter built and tested as a 500 W-100 kHz breadboard setup using IGBTs is verified and evaluated on the basis of simulation and theoretical circuit analysis.

ZVS Bridge Leg and ZCS Bridge Leg DC-DC Converter with Tapped Inductor Filter

In this paper, a novel full-bridge soft-switching phase-shifted PWM DC-DC power converter circuit is presented. A tapped inductor filter is implemented in the proposed converter topology to achieve soft switching commutation for the active power switches under wide load variation range, to minimize circulating current without using additional resonant circuit and/or auxiliary switching devices. The effectiveness of the proposed soft-switching DC-DC power converter is verified in experiment with 2kW-100kHz breadboard circuit using IGBTs.

Double Two Switch Forward Soft Switching PWM DC-DC Converter.

A novel prototype of a double two-switch forward transformer linked zero-voltage and zero-current mode soft-switching (ZVZCS) pulse width modulation (PWM) DC-DC power converter using IGBTs for high power applications is presented. Based on a conventional two-switch forward transformer linked PWM DC-DC converter topology, this converter circuit configuration doesn't include any complex auxiliary resonant circuit. Combining two identical two-switch forward type DC-DC power conversion circuits with a tapped-inductor type DC smoothing filter into a power DC-DC conversion system makes it possible to achieve soft-switching conditions for the active power switches with aid of lossless snubber capacitors and transformer parasitic inductors. Lowered peak voltage across the power switching devices and their related peak current stresses, no transformer saturation effect, reducing of idle and circulating currents through circuit components are practically attained for this converter. This soft-switching PWM DC-DC power converter has some unique advantages such as better power conversion efficiency, lowered output DC ripple current, high power density, constant frequency PWM control scheme, cost effective and wide soft-switching operation range under load variations and PWM regulation settings for high power utilizations. The basic operating principle of the new soft switching power converter treated here is illustrated with approximate periodic steady-state circuit analysis for each mode equivalent circuit. The practical effectiveness of the proposed soft-switching DC-DC power converter is confirmed by the simulation results and is experimentally evaluated on basis of 500W-100kHz breadboard setup using the fast switching IGBTs.

Two-switch forward soft-switching PWM DC-DC power converter

A novel prototype is presented of a two-switch forward soft-switching PWM DC-DC power converter with reduced switching and conduction power losses, which can operate under two soft commutations of zero voltage and zero current of full bridge circuit topology.