Features Zero-voltage Switching Research Articles

Extension of Zero-Voltage Switching Region of Wide Volage Ratio Range Dual-Active-Bridge Converter by LC Antiresonant Network

Zero-voltage switching (ZVS) for dual active bridge (DAB) with wide voltage conversion ratio has a contradiction with low conduction loss, especially under light power transmission. Root mean square (RMS) increase of inductor current is unavoidable just by optimizing modulation schemes. Inspired by the various frequency (VF) and various inductor (VI), this article proposes a DAB converter with the capability of regulating the impedance of the resonant tank to extend the ZVS region. With an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> antiresonant circuit in series with original inductor, the equivalent inductance of the resonant network of the proposed converter increases along with the switching frequency within the designed frequency range. Thereby, when the voltage mismatches and the transferred power decreases, a large impedance is obtained by slightly increasing frequency to help to achieve ZVS. Moreover, the proposed DAB is found that single phase shift (SPS) has nearly identical characteristics of ZVS and conduction loss compared with multiple phase shift modulation. The benefit of this is that the complexity of close-loop control is significantly reduced just considering the switching frequency and external shift phase. In addition, ZVS characteristics and optimal control method are analyzed in detail. Finally, a 2 kW 360-400V/40-60V prototype is built, and the main experimental results are provided to verify the feasibility of the proposed converter and soft switching range of all switches.

An Input-Current Shaping and Soft-Switching Drive Circuit Applied to a Piezoelectric Ceramic Actuator.

Piezoelectric ceramic actuators utilize an inverse piezoelectric effect to generate high-frequency vibration energy and are widely used in ultrasonic energy conversion circuits. This paper presents a novel drive circuit with input-current shaping (ICS) and soft-switching features which consists of a front AC-DC full-wave bridge rectifier and a rear DC-AC circuit combining a stacked boost converter and a half-bridge resonant inverter for driving a piezoelectric ceramic actuator. To enable ICS functionality in the proposed drive circuit, the inductor of the stacked boost converter sub-circuit is designed to operate in boundary-conduction mode (BCM). In order to allow the two power switches in the proposed drive circuit to achieve zero-voltage switching (ZVS) characteristics, the resonant circuit of the half-bridge resonant inverter sub-circuit is designed as an inductive load. In this paper, a prototype drive circuit for providing piezoelectric ceramic actuators was successfully implemented. Experimental results tested at 110 V input utility voltage show that high power factor (PF > 0.97), low input current total harmonic distortion (THD < 16%), and ZVS characteristics of the power switch were achieved in the prototype drive circuit.

Analysis and Design of a High-Frequency Isolated Dual-Transformer DC-DC Resonant Converter

This paper presents the operation, analysis, design, simulation, and experimental results for a proposed Dual-Transformer DC-DC Resonant Converter (DTRC). A three-arm bridge is employed on the input side and an H-type bridge is employed on the output side of the DTRC, and the two bridges are connected with two high-frequency (HF) transformers. By optimizing the ratio k of the two HF transformers, the proposed DTRC has a lower boundary power for losing zero-voltage switching (ZVS). That means the DTRC has a wider ZVS operation range and lower switching loss when compared with a traditional soft-switching pulse width modulation (PWM) resonant converter. The operation principle, power transfer, ZVS characteristics, and design procedures are analyzed in detail. Both simulation and experimental results prove the feasibility and superiority of the proposed Dual-Transformer DC-DC Resonant Converter.

Analysis and Control of Critical Conduction Mode High-Frequency Single-Phase Transformerless PV Inverter

This article presents a critical conduction mode (CRM) single-phase transformerless full-bridge inverter in a residential photovoltaic system. The CRM full-bridge inverter in bipolar mode features zero-voltage switching capability for the whole line cycle. This enables the inverter to push switching frequency up to hundreds of kHz and achieve high power density with high efficiency. However, CRM operation incurs nonconstant common mode (CM) voltage during the resonant period, causing high frequency leakage current. To minimize the leakage current, a new switching modulation strategy is proposed introducing triangular current mode (TCM) near the ac voltage zero crossing. The switching modulation scheme alleviates the CM voltage by shortening the resonant period and consequently reduces the leakage current. Then, discontinuous conduction mode is inserted between the CRM and TCM operation regions to improve light load efficiency. In this article, the basic operation principle of the CRM full-bridge inverter, impacts of CRM operation on the leakage current, and details of the proposed switching modulation method are discussed. Experimental results with a 2.4-kW prototype built with GaN devices validate its performance.

A Novel and Cost-Effective Drive Circuit for Supplying a Piezoelectric Ceramic Actuator with Power-Factor-Correction and Soft-Switching Features

This paper proposes a novel and cost-effective drive circuit for supplying a piezoelectric ceramic actuator, which combines a dual boost AC-DC converter with a coupled inductor and a half-bridge resonant DC-AC inverter into a single-stage architecture with power-factor-correction (PFC) and soft-switching characteristics. The coupled inductor of the dual boost AC-DC converter sub-circuit is designed to work in discontinuous conduction mode (DCM), so the PFC function can be realized in the proposed drive circuit. The resonant tank of the half-bridge resonant inverter sub-circuit is designed as an inductive load, so that the two power switches in the presented drive circuit can achieve zero-voltage switching (ZVS) characteristics. A 50 W-rated prototype drive circuit providing a piezoelectric ceramic actuator has been successfully implemented in this paper. From the experimental results at 110 V input utility-line voltage, the drive circuit has the characteristics of high power factor and low input current total-harmonic-distortion factor, and two power switches have ZVS characteristics. Therefore, satisfactory outcomes from measured results prove the function of the proposed drive circuit.

A Low-THD Two-Switch PFC DCM Boost Rectifier for Aviation Applications

In this article, a new two-switch, single-phase, power-factor-correction, discontinuous-conduction-mode boost rectifier that features zero-voltage switching turn on and can achieve less than 5% input-current total harmonic distortion (THD) by injecting a simple feedforward signal obtained from input and output voltages to the output voltage feedback control is introduced. Since low THD is achieved without high- bandwidth active current shaping control, the proposed topology is suitable for modern aviation applications that require line frequency up to 800 Hz. The evaluation was performed on a 320-W prototype designed to operate from 94–134-V line input and deliver 220-V dc output. The prototype achieves 3.3% THD at full load over the line frequency range from 360 to 800 Hz and meets the required harmonic limits specified by the DO-160 standard that describes the environmental conditions and test procedures for airborne equipment.

A Single-Stage LED Streetlight Driver with Soft-Switching and Interleaved PFC Features

This paper presents a single-stage driver with soft-switching and interleaved power-factor correction (PFC) features suitable for light-emitting diode (LED) energy-saving streetlight applications. The proposed LED streetlight driver integrates an interleaved buck-boost PFC converter with coupled inductors and a half-bridge LLC resonant converter into a single-stage power-conversion circuit with reduced voltage stress on the DC-linked capacitor and power switches, and it is suitable for operating at high utility-line voltages. Furthermore, coupled inductors in the interleaved buck-boost PFC converter are operated in discontinuous-conduction mode (DCM) for accomplishing PFC, and the half-bridge LLC resonant converter features zero-voltage switching (ZVS) to reduce switching losses of power switches, and zero-current switching (ZCS) to decrease conduction losses of power diodes. Operational modes and design considerations for the proposed LED streetlight driver are introduced. Finally, a 144 W (36V/4A)-rated LED prototype driver is successfully developed and implemented for supplying a streetlight module and operating with a utility-line input voltage of 220 V. High power factor, low output-voltage ripple factor, low output-current ripple factor, and high efficiency are achieved in the proposed LED streetlight driver.

Three-Level TAIPEI Rectifier—Analysis of Operation, Design Considerations, and Performance Evaluation

A new low-cost three-phase four-switch three-level zero-voltage-switching (ZVS) discontinuous-current-mode power-factor-correction boost rectifier, for short named the three-level TAIPEI rectifier, that achieves a low input-current total harmonic distortion (THD) and features ZVS of all the switches is introduced. Since in the proposed rectifier the voltage stress of the four switches is equal to one-half of the output voltage, the rectifier can utilize switches with a lower voltage rating that, generally, have lower conduction losses. To reduce the switching-frequency range and maximize the light-load efficiency, the control is implemented by a combination of variable-switching frequency and phase-shift pulse-width modulation control. Detailed design guidelines for and performance evaluation of a three-phase 6-kW prototype designed for the line-to-line voltage range from 340 $V_{{\rm RMS}}$ to 520 $V_{{\rm RMS}}$ are presented. The prototype rectifier exhibits efficiency in the 96%–98% range and achieves less than 5% input-current THD over the entire nominal input-voltage range (380–480 $V_{L-L,{\rm RMS}}$ ) and above 50% of full load.

An improved forward converter with PFC and ZVS features for split-phase charger applications

In this paper, an improved forward converter with power-factor-correction (PFC) and zero-voltage-switching (ZVS) features for split-phase charger applications is proposed. For a universal line input, the improved forward converter can implement PFC feature, which can improve power quality and reduce total-harmonic-distortion (THD) of power line. In addition, the active switches of the improved forward converter can be operated under a ZVS condition, in which the switching losses of the active switches can be reduced. Therefore, the improved forward converter can achieve high power quality and high conversion efficiency. Furthermore, the split-phase charger can also improve unbalanced voltage of series-connected batteries to extend utility rate. Finally, the improved forward converter with PFC and ZVS features for split-phase charger applications is built and implemented. Experimental results are presented to verify the performance and the feasibility of the improved forward converter.

Analysis, Design, and Experimental Results of the Semidual-Active-Bridge Converter

A new soft-switching circuit topology derived from the popular dual-active-bridge converter (DAB) topology is proposed for applications requiring only unidirectional power flow such as the dc-dc stage of a photovoltaic power converter, and battery charger for electric vehicles. The topology named as the semidual active bridge (S-DAB) is obtained by replacing the fully active (four switches) bridge on the load side of a DAB by a semiactive (two switches and two diodes) bridge. In addition to the reduced number of active switches, the topology offers several other advantages including extended zero-voltage switching (ZVS), and smaller output filter requirement. The operating principles, waveforms in different intervals and expression for power transfer, which differ significantly from the basic DAB topology, are presented in detail. The ZVS characteristics and requirements are analyzed in detail and compared to those of DAB. A small-signal model of the new configuration is also derived. The analysis and performance of S-DAB are validated through extensive simulation and experimental results from a 1-kW hardware prototype.

A Power Supply System with ZVS and Current-Doubler Features for Hybrid Renewable Energy Conversion

In this paper, a power supply system for hybrid renewable energy conversion is proposed, which can process PV (photovoltaic) power and wind-turbine energy simultaneously for step-down voltage and high current applications. It is a dual-input converter and mainly contains a PV energy source, a wind turbine energy source, a zero-voltage-switching (ZVS) forward converter, and a current-doubler rectifier. The proposed power supply system has the following advantages: (1) PV-arrays and wind-energy sources can alternatively deliver power to the load during climate or season alteration; (2) maximum power point tracking (MPPT) can be accomplished for both different kinds of renewable-energy sources; (3) ZVS and synchronous rectification techniques for the active switches of the forward converter are embedded so as to reduce switching and conducting losses; and (4) electricity isolation is naturally obtained. To achieve an optimally dynamic response and to increase control flexibility, a digital signal processor (DSP) is investigated and presented to implement MPPT algorithm and power regulating scheme. Finally, a 240 W prototype power supply system with ZVS and current-doubler features to deal with PV power and wind energy is built and implemented. Experimental results are presented to verify the performance and the feasibility of the proposed power supply system.

The TAIPEI Rectifier—A New Three-Phase Two-Switch ZVS PFC DCM Boost Rectifier

A new, three-phase, two-switch, power-factor-correction (PFC) rectifier that can achieve less than 5% input-current total harmonic distortion (THD) and features zero-voltage switching (ZVS) of all the switches over the entire input-voltage and load ranges is introduced. The proposed rectifier also offers automatic voltage balancing across the two output capacitors connected in series, which makes it possible to use downstream converters designed with lower voltage-rated component that offer better performance and are less expensive than their high-voltage-rated counterparts. In addition, the proposed rectifier also exhibits low common-mode EMI noise. The performance of the proposed rectifier was evaluated on a 2.8-kW prototype with a 780-V output that was designed to operate in 340-520-VL-L, RMS input-voltage range.

A SINGLE-STAGE PHASE-SHIFTED FULL-BRIDGE ELECTRONIC BALLAST FOR HIGH-PRESSURE MERCURY LAMPS

This paper presents a single-stage high-frequency full-bridge electronic ballast for high-pressure mercury lamps in high-luminance LCD projector systems. The studied electronic ballast is found to have high conversion efficiency due to its single-stage circuit with zero-voltage switching features. A high power factor can be achieved by using developed single-stage topology. The operation principles and design considerations are analyzed and discussed in detail. A laboratory prototype is designed and implemented for driving a 150 W projector lamp. The simulation and experimental waveforms are given to verify the feasibility of the proposed method.

Snubberless Bidirectional DC–DC Converter With New CLLC Resonant Tank Featuring Minimized Switching Loss

A bidirectional dc–dc converter (BDC) with a new CLLC-type resonant tank, which features zero-voltage switching (ZVS) for the input inverting choppers and zero-current switching (ZCS) for the output rectifier switches, regardless of the direction of the power flow, is proposed in this paper. Possessing the very optimal ZVS <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$+$</tex></formula> ZCS soft-switching feature, this proposed converter will have a minimized switching loss if all of the main switches are implemented with metal–oxide–semiconductor field-effect transistors, and thereby, the proposed converter is fully soft switched and totally snubberless. The detail operation principles, as well as the design considerations, are presented. The methodologies to develop a unidirectional ZVS <formula formulatype="inline" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex Notation="TeX">$+$</tex></formula> ZCS dc–dc converter for the corresponding pulsewidth modulation and frequency modulation converters are proposed. The approach on how to construct a fully soft-switched BDC has also been proposed and analyzed. Finally, a topology extension is made, and another fully soft-switched BDC is derived. A prototype, which interfaces the 400–48-V dc buses for the uninterrupted power supply system with a power rating of 500 VA, was developed to verify the validity and applicability of this proposed converter. The highest applicable conversion efficiencies for the bidirectional operational modes are exceeding 96%.

Full ZVS-Range Transient Current Buildup Half-Bridge Converter With Different ZVS Operations to Load Variation

A full zero voltage switching (ZVS) range transient current buildup half-bridge converter is proposed. The proposed converter controls the secondary synchronous switches to build up the current for the ZVS operation. In addition, the blocking capacitor in the secondary side of the transformer is used to make the different current buildups and different ZVS operations with the load variation. Furthermore, it eliminates the DC offset of the magnetizing current. Therefore, the considerably effective ZVS characteristics can be ensured in the full-load ranges without any additional conduction losses.

Novel interleaved ZVS converter with ripple current cancellation

AbstractThis paper presents a zero voltage switching (ZVS) converter with interleaved pulse‐width modulation scheme. An active clamp circuit is adopted in the proposed converter to recycle the energy stored in the leakage inductor of the transformer and reduce the voltage stress of the main power switch in the converter. The ZVS feature of switches can be achieved due to the resonance during the transition interval of two power switches. Two full‐wave rectifiers with ripple current cancellation are connected in parallel at the output side to reduce the current stress of the secondary winding of transformers. Instead of the conventional interleaved forward converter, power switches in the proposed converter can perform the functions of both forward converter and active clamp at the same time. Therefore, the circuit components in the power circuit are less than that of in the conventional interleaved forward converter. The operation principle and system analysis of the proposed converter are provided. Some experimental results for a 240 W (12 V/20 A) prototype are provided to demonstrate the effectiveness of the proposed converter. Copyright © 2008 John Wiley &amp; Sons, Ltd.

Asymmetrical pulse-width modulation bidirectional DC–DC converter

System analysis of a bidirectional DC–DC converter for a fuel cell electric vehicle driving system is presented. The proposed converter is based on a zero voltage switching (ZVS) half-bridge converter with centre-tapped rectifier at the secondary side of the transformer. The asymmetrical pulse-width modulation is used in the converter to achieve ZVS feature of power switches and to regulate the output voltage at the desired value. The proposed converter has the advantages of high efficiency, low circuit components and simple circuit configuration. The operating principle and the system analysis are described and discussed in detail. Finally, the experimental results for the proposed converter are provided to verify the theoretical analysis.

Novel zero voltage switching dual-switch forward converter with ripple current cancellation

A zero voltage switching (ZVS) dual-switch forward converter with ripple current cancellation is presented. In the proposed converter, active clamp circuit is used to clamp the voltage stresses and to realise ZVS of all switching devices. Active clamp boost converter with power factor correction is used in the front stage of the proposed converter to draw a sinusoidal line current from the AC source and to maintain a constant voltage at the DC bus. The second stage of the proposed converter is a dual-switch forward converter with current doubler rectifier to obtain the isolated low output voltage. Active clamp circuit used in the DC/DC converter can recycle the energy stored in the leakage inductor and magnetising inductor so that the voltage stresses on the switches are limited and the ZVS feature is realised. The current doubler rectifier offers the ripple current cancellation at the output capacitor and reduces the current stress of the transformer secondary winding. The circuit configuration and principle of operation are analysed and discussed in detail. Experimental results with a laboratory prototype based on a 90–260 Vrms input and 12 V/30 A output were provided to verify the effectiveness of the proposed converter.

Analysis, simulation and verification of a bipolar current source power resonant inverter

AbstractA high‐frequency bipolar current source resonant inverter introduced in this paper has dramatic zero‐voltage‐switching (ZVS) characteristic. The analytic expressions of the resonant voltage and current are given. It indicates that the resonant waveform is composed of two parts, i.e. the oscillatory component and the stationary component. In special cases, the resonant waveform degenerates into the mono‐frequency component, as presents the graceful sinusoidal wave with very low total harmonic distortion (THD) value. Based on the closed‐form voltage and current, the component stresses on reactive elements are obtained. The impact of different component values and operating frequencies on ZVS feature is also discussed. It should be noted that the ZVS merit may be lost if the components are carelessly selected. The validity of the theoretical analysis has been proven with Pspice simulations and experimental results. Copyright © 2004 John Wiley Sons, Ltd.

Pulsed voltage-fed sustain circuit for AC plasma display drive

A new sustain circuit for an AC plasma display drive is proposed. The proposed circuit uses the instantaneous peak current flowing through the inductor during the charging and discharging of a plasma display panel, to recover most of the energy lost by the capacitive displacement current. This circuit can be realised with a small part-count, and gives the zero-voltage switching characteristics to all the switches even in the presence of a parasitic resistance, essential for the design of a sustain circuit for an AC plasma display. The capacitive displacement current and the required reactive power are greatly reduced in the proposed circuit. A comparative analysis and experimental results are presented to show the validity of the proposed energy recovery circuit.