Ahmad Mousavi

A Comparative Study of a New ZCS DC–DC Full-Bridge Boost Converter With a ZVS Active-Clamp Converter

Pulse width modulation (PWM) current-fed full-bridge dc-dc boost converters are typically used in applications where the output voltage is considerably higher than the input voltage. In this paper, a comparison is made between two converter topologies of this type-the standard zero-voltage switching (ZVS) active-clamp topology and a new zero-current switching (ZCS) topology. This paper begins with a review of the operation of the ZVS active-clamp converter and that of ZCS converters in general; the advantages and disadvantages of each approach are stated. A new ZCS-PWM current-fed dc-dc boost full-bridge converter is then introduced. The operation of the new converter is explained and analyzed, and a procedure for the design of its key components is given and demonstrated with an example. Experimental results obtained from a prototype of a ZVS active-clamp converter and the new ZCS converter are presented. Finally, a comparison of the performance of the two converters is made and conclusion based on this comparison is stated.

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 converters performance and the concepts presented in the paper.

A Study of AC-DC ZVS-PWM Boost Converters with Silicon Carbide Diodes

A study of ac-dc zero-voltage switched (ZVS) pulsewidth modulated (PWM) boost converters with silicon carbide (SiC) boost diodes instead of silicon (Si) boost diodes is presented in the paper. The paper reviews the general principles of active auxiliary circuits that are used to help the main boost power switch turn on with ZVS, then explains how these circuits operate differently when SiC boost diodes are used in place of Si diodes. Considerations that should be taken into account when designing a ZVS-PWM boost converter with SiC diodes are discussed, and experimental results obtained from a prototype of an example converter are presented to confirm the concepts discussed in the paper.

ZVS and ZCS dc-dc PWM full-bridge fuel cell converters

PWM current-fed full-bridge dc-dc boost converters are typically in applications where the output voltage is considerably higher than the input voltage, such as fuel cell converters. The zero-voltage switching (ZVS) active-clamp converter is the most commonly used converter of this type. Zero-current switching (ZCS) techniques have also been used in current-fed full bridge converters, but not in fuel cell converters. In the paper, a comparison is made between the ZVS active-clamp full-bridge converter and a ZCS full-bridge converter. The operation of the two converters is discussed in detail and experimental results obtained from each converter are presented and compared.

An ac-dc single-stage full-bridge PWM converter with bridgeless input

A new ac-dc single-stage full-bridge PWM converter is proposed in the paper. The converter can operate with an excellent input power factor, continuous input and output currents, and has a bridgeless input that helps reduce conduction losses. In the paper, the basics of bridgeless ac-dc converters are briefly reviewed, the operation of the proposed converter is discussed, and experimental results that were obtained from a prototype and that confirm its feasibility are presented.

A novel ZVS-PWM dc-dc converter for bidirectional applications with steep conversion ratio

A new soft-switched bidirectional dc-dc converter with coupled inductors is proposed in the paper. The proposed converter can operate with soft-switching, fixed switching frequency, and the switch stresses of a conventional PWM converter with coupled inductor regardless of the direction of power flow. These features are due to a very simple auxiliary active clamp circuit that is operational regardless of the direction of power flow. In the paper, the converters operation is explained. Experimental results obtained from a prototype, which confirm the feasibility of the proposed converter, are also presented.

A novel ZCS-PWM full-bridge converter with a simple active auxiliary circuit

A new soft-switching 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 a very simple active auxiliary circuit and a few passive components. The paper presents the new converter and then discusses its operation, steady-state characteristics and design. Experimental results obtained from a converter prototype are presented to validate the converters performance and the concepts presented in the paper.

ZCS PWM bidirectional converter with one auxiliary switch

Dc-dc bidirectional converters transfer energy between two different dc sources. Soft switching in both directions of operation has been difficult in non-isolated bidirectional converters. To achieve soft switching in the main switches in such converters, usually two independent auxiliary circuits with multiple auxiliary switches are used. A ZCS PWM bidirectional converter is proposed in this paper. In the proposed bidirectional converter a novel yet simple auxiliary circuit with only one auxiliary switch has been applied to provide soft switching at both buck and boost modes of operation. The soft switching range of the proposed converter is independent of the duty cycle and operates with a simple control circuit. In this paper, description and operating principles of the proposed converter are discussed and experimental results obtained from a 500W, 100V–400V prototype are presented to validate the feasibility of the converter

Analysis and design of a new ZCS-PWM full-bridge fuel cell converter

PWM full-bridge dc-dc boost converters are used in applications where the output voltage is considerably higher than the input voltage. Zero-current switching (ZCS) is typically implemented in these converters. Previous proposed ZCS-PWM full-bridge boost converters, however, have a number of drawbacks that are related to the circulating current that must be generated to divert current away from the main full-bridge switches so that they can be turned off with ZCS. This circulating current is a source of significant converter losses and peak switches stresses. In order to reduce these problems, a new ZCS-PWM dc-dc full-bridge boost converter is proposed in the paper. In the paper, the operation of the proposed converter is explained, and a detailed mathematical analysis of its steady-state operation is performed. A procedure for the design of the converter is given and demonstrated with an example. The feasibility of the converter is confirmed with results obtained from an experimental prototype.

A ZCS-PWM Full-Bridge Boost Converter for Fuel-Cell Applications

A new ZCS-PWM dc-dc full-bridge boost converter is proposed in the paper. The proposed converter is well-suited to be used as a fuel cell converter where low input voltage / high output voltage conversion is required. In the paper, the operation of the proposed converter is explained in detail, and its features and design are discussed. The feasibility of the converter is confirmed with results that are obtained from an experimental prototype.