Solid-state switch-mode rectification converters have reached a matured level for improving power quality in terms of power-factor correction (PFC), reduced total harmonic distortion at input AC mains and precisely regulated DC output in buck, boost, buck-boost and multilevel modes with unidirectional and bidirectional power flow. This paper deals with a comprehensive review of improved power quality converters (IPQCs) configurations, control approaches, design features, selection of components, other related considerations, and their suitability and selection for specific applications. It is targeted to provide a wide spectrum on the status of IPQC technology to researchers, designers and application engineers working on switched-mode AC-DC converters. A classified list of more than 450 research publications on the state of art of IPQC is also given for a quick reference.

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A review of single-phase improved power quality AC-DC converters

This paper overviews theoretical and practical design issues related to inductive power transfer systems and verifies the developed theory using a practical electric vehicle battery charger. The design focuses on the necessary approaches to ensure power transfer over the complete operating range of the system. As such, a new approach to the design of the primary resonant circuit is proposed, whereby deviations from design expectations due to phase or frequency shift are minimized. Of particular interest are systems that are neither loosely nor tightly coupled. The developed solution depends on the selected primary and secondary resonant topologies, the magnetic coupling coefficient, and the secondary quality factor.

Design considerations for a contactless electric vehicle battery charger

DC–DC converters with voltage boost capability are widely used in a large number of power conversion applications, from fraction-of-volt to tens of thousands of volts at power levels from milliwatts to megawatts. The literature has reported on various voltage-boosting techniques, in which fundamental energy storing elements (inductors and capacitors) and/or transformers in conjunction with switch(es) and diode(s) are utilized in the circuit. These techniques include switched capacitor (charge pump), voltage multiplier, switched inductor/voltage lift, magnetic coupling, and multistage/-level, and each has its own merits and demerits depending on application, in terms of cost, complexity, power density, reliability, and efficiency. To meet the growing demand for such applications, new power converter topologies that use the above voltage-boosting techniques, as well as some active and passive components, are continuously being proposed. The permutations and combinations of the various voltage-boosting techniques with additional components in a circuit allow for numerous new topologies and configurations, which are often confusing and difficult to follow. Therefore, to present a clear picture on the general law and framework of the development of next-generation step-up dc–dc converters, this paper aims to comprehensively review and classify various step-up dc–dc converters based on their characteristics and voltage-boosting techniques. In addition, the advantages and disadvantages of these voltage-boosting techniques and associated converters are discussed in detail. Finally, broad applications of dc–dc converters are presented and summarized with comparative study of different voltage-boosting techniques.

/pdf/step-up-dc-dc-converters-a-comprehensive-review-of-voltage-6dlytctzg2.pdf

Step-Up DC–DC Converters: A Comprehensive Review of Voltage-Boosting Techniques, Topologies, and Applications

The photovoltaic (PV) grid-connected power system in the residential applications is becoming a fast growing segment in the PV market due to the shortage of the fossil fuel energy and the great environmental pollution. A new research trend in the residential generation system is to employ the PV parallel-connected configuration rather than the series-connected configuration to satisfy the safety requirements and to make full use of the PV generated power. How to achieve high-step-up, low-cost, and high-efficiency dc/dc conversion is the major consideration due to the low PV output voltage with the parallel-connected structure. The limitations of the conventional boost converters in these applications are analyzed. Then, most of the topologies with high-step-up, low-cost, and high-efficiency performance are covered and classified into several categories. The advantages and disadvantages of these converters are discussed. Furthermore, a general conceptual circuit for high-step-up, low-cost, and high-efficiency dc/dc conversion is proposed to derive the next-generation topologies for the PV grid-connected power system. Finally, the major challenges of high-step-up, low-cost, and high-efficiency dc/dc converters are summarized. This paper would like to make a clear picture on the general law and framework for the next-generation nonisolated high-step-up dc/dc converters.

Review of Nonisolated High-Step-Up DC/DC Converters in Photovoltaic Grid-Connected Applications

A detection method for use in a primary unit of an inductive power transfer system, the primary unit being operable to transmit power wirelessly by electromagnetic induction to at least one secondary unit of the system located in proximity to the primary unit and/or to a foreign object located in said proximity, the method comprising: driving the primary unit so that in a driven state the magnitude of an electrical drive signal supplied to one or more primary coils of the primary unit changes from a first value to a second value; assessing the effect of such driving on an electrical characteristic of the primary unit; and detecting in dependence upon the assessed effect the presence of a said secondary unit and/or a foreign object located in proximity to said primary unit.

Inductive power transfer

Using a tapped inductor for reducing conduction losses in a soft-switching PWM DC-DC converter

The authors describe a resonant PWM (pulse-width-modulated) inverter-linked DC-DC converter which uses the high-voltage transformer parasitic LC circuit parameters as resonant components and the high-voltage cable input capacitance as smoothing filter. Theoretical results obtained by computer-aided simulation and experimental results obtained by a test circuit including prototype transformers are illustrated and discussed from a practical point of view. The phase-shift PWM control for adjusting the DC output voltage of the resonant converter is presented. One of the advantages of this converter is minimization of circuit components; this kind of circuit topology can minimize the size and weight of power supply systems and can be applied to the filament heating circuit connected to the cathode of the X-ray tube. >

High-frequency parallel resonant converter for X-ray generator utilizing parasitic circuit constants of high voltage-transformer and -cables

An improved single-ended push-pull (SEPP) half-bridge type zero-voltage soft-switching pulse width modulation (ZVS-PWM) DC-DC power converter is presented in this paper, which makes use of a saturable reactor-assisted lossless capacitor type zero voltage soft-switching method. The SEPP power converter with a high-frequency forward and flyback hybrid transformer link has some advantages such as lowered switching and conduction losses, soft-switching transition operation over a wide load range, constant frequency PWM regulation and minimized Electro Magnetic Interference (EMI) as well as Radio Frequency Interference (RFI) noises. Its operating principle is illustrated and its periodic steady-state circuit analysis is implemented. In order to demonstrate the remarkable effectiveness of this converter's characteristics, feasibility experiments are conducted with a 150 W/200 kHz prototype of a high-frequency link ZVS-PWM DC-DC converter using power MOSFETs with an ultrafast soft-recovery diode.

Zero voltage soft-commutation PWM DC-DC converter with saturable reactor switch-cascaded diode rectifier

A novel prototype of the active voltage clamping capacitor circuit-assisted edge-resonant ZVS-PWM high-frequency inverter, which uses newly developed generation consumer application specific IGBTs, is presented. This soft-switching inverter can operate under the condition of a VPCF power regulation scheme. This high-frequency inverter, with asymmetrical PWM regulation in addition to the active power filtering functions, has been developed for consumer IH cooking appliances such as IH rice cookers and warmers, IH cooking heaters and IH hot water producers. The application of specific trench-gate IGBTs with low saturation voltage characteristics, which are used for edge-resonant ZVS-PWM high-frequency inverters is particularly designed and introduced to reduce the conduction power losses of the power semiconductor devices. The switching losses of this inverter can also easily be reduced with the aid of the ZVS commutation technique. This voltage-source-type edge-resonant ZVS-PWM inverter, which uses the latest specially designed IGBTs in addition to various types of trench-gate IGBTs, is evaluated and discussed from a practical energy-saving application point of view.

Performance evaluation of edge-resonant ZVS-PWM high-frequency inverter using trench-gate IGBTs for consumer induction cooking heater

A novel prototype of auxiliary resonant DC link (ARDCL) snubber is proposed. The paper also describes a three-phase space voltage vector modulated sinewave soft-switching inverter using the proposed ARDCL snubber circuit, which together with new voltage vector correction principle can produce high-performance output voltage waveforms. The output voltage waveforms obtained by the software processing of the inverter are able to achieve a high quality sinewave on the basis of the new correction principle. The effectiveness of the resonant DC link three-phase voltage source soft-switching inverter is proven from a practical point of view.

http://ieeexplore.ieee.org/iel5/2194/19858/00918378.pdf

Mutsuo Nakaoka

Papers

Using a tapped inductor for reducing conduction losses in a soft-switching PWM DC-DC converter

High-frequency parallel resonant converter for X-ray generator utilizing parasitic circuit constants of high voltage-transformer and -cables

Zero voltage soft-commutation PWM DC-DC converter with saturable reactor switch-cascaded diode rectifier

Performance evaluation of edge-resonant ZVS-PWM high-frequency inverter using trench-gate IGBTs for consumer induction cooking heater

Evaluations of voltage-source soft-switching inverter with single auxiliary resonant snubber