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

The authors discuss high-voltage power conversion. Conventional series connection and three-level voltage source inverter techniques are reviewed and compared. A novel versatile multilevel commutation cell is introduced: it is shown that this topology is safer and more simple to control, and delivers purer output waveforms. The authors show how this technique can be applied to either choppers or voltage-source inverters and generalized to any number of switches.<<ETX>>

Multi-level conversion : high voltage choppers and voltage-source inverters

Introduction to Electromagnetic Compatibility

In the first part of this paper, three-phase power factor correction (PFC) rectifier topologies with sinusoidal input currents and controlled output voltage are derived from known single-phase PFC rectifier systems and/or passive three-phase diode rectifiers. The systems are classified into hybrid and fully active pulsewidth modulation boost-type or buck-type rectifiers, and their functionality and basic control concepts are briefly described. This facilitates the understanding of the operating principle of three-phase PFC rectifiers starting from single-phase systems, and organizes and completes the knowledge base with a new hybrid three-phase buck-type PFC rectifier topology denominated as Swiss Rectifier. Finally, core topics of future research on three-phase PFC rectifier systems are discussed, such as the analysis of novel hybrid buck-type PFC rectifier topologies, the direct input current control of buck-type systems, and the multi-objective optimization of PFC rectifier systems. The second part of this paper is dedicated to a comparative evaluation of four rectifier systems offering a high potential for industrial applications based on simple and demonstrative performance metrics concerning the semiconductor stresses, the loading and volume of the main passive components, the differential mode and common mode electromagnetic interference noise level, and ultimately the achievable converter efficiency and power density. The results are substantiated with selected examples of hardware prototypes that are optimized for efficiency and/or power density.

The Essence of Three-Phase PFC Rectifier Systems—Part II

An advantage for some wide bandgap materials, that is often overlooked, is that the thermal coefficient of expansion (CTE) is better matched to the ceramics in use for packaging technology. It is shown that the optimal choice for uni-polar devices is clearly GaN. It is further shown that the future optimal choice for bipolar devices is C (diamond) owing to the large bandgap, high thermal conductivity, and large electron and hole mobilities. A new expression relating the critical electric field for breakdown in abrupt junctions to the material bandgap energy is derived and is further used to derive new expressions for specific on-resistance in power semiconductor devices. These new expressions are compared to the previous literature and the efficacy of specific power devices, such as heterojunction MOSFETs, using GaN are discussed.

An assessment of wide bandgap semiconductors for power devices

This paper presents a study on the gate driver circuitries that need to be implemented to drive several power devices when associated in series connection. More specifically, the propagation paths of parasitic currents through the gate driver circuitries, exited under high switching speeds, are studied in different configurations trying to minimize common mode currents generated. In a gate driver circuitry for a regular low side–high side switching cell configuration with one upper switch and one lower switch, the voltage transient dv/dt at the middle point applied across the primary-secondary parasitic capacitance of gate driver supplies, and control signal isolation units are the reasons for the generation of conducted electromagnetic interference (EMI) perturbations. In complex power converters, multicell, multilevel, or even series connection of power devices, many driver circuits are required and implemented. Similarly, in such converters, there are several dv/dt sources generated at different floating points producing conducted EMI perturbations from the power part to the control part through many gate driver circuitries. Based on previous works, this paper analyzes the best configuration to minimize parasitic currents, especially reducing the conducted common mode currents in series connected transistors topologies. Simulations and practical results validate the analysis for two power devices in series connection, and then the extrapolations for more power devices in series connection, up to six are discussed and analyzed with the help of simulations results.

Gate Driver Supply Architectures for Common Mode Conducted EMI Reduction in Series Connection of Multiple Power Devices

PFC rectifiers produce EMI. Because of standard requirements, high frequency disturbances must be studied in order to be reduced. A new forecast method is presented. It is based on a frequency domain analysis. It saves time and computer memory compared to classical time domain analysis methods. A description and valid conditions are given. The method is applied to the single switch boost rectifier in continuous mode operation using a PWM control strategy. It is compared to circuit oriented simulation and experimental results which validate its interest.

A new method for EMI study in boost derived PFC rectifiers

This paper deals with the design and the realization of an integrated isolated HF dc-to-dc converter for low-voltage and low-power conditioning applications (3.3 V and 1 W) including galvanic isolation. It is based on the 3-D integration of several elementary silicon dies in which essential components such as the inverter, the rectifier, the HF transformer, the input and output capacitors, and the output inductor have been integrated. The paper deals with the silicon integration of all these elements, with the presentation of our work being related with the state of the art. Then, it focuses on an estimate of the whole converter functional performance at 1-MHz switching frequency. Practical but partial implementation was carried out. The inverter and the rectifier are designed in CMOS technology (Austria Micro Systems 0.35 μm) and have been optimized to operate at HF (1 MHz) to reduce the size of passive devices. We have monolithically integrated all that is necessary for this function. The transformer, as well as the inductor and the capacitors, is also integrated on separate silicon dies. Their integration is discussed, as well as their design and practical characterization. Based on a distributed construction, the overall converter efficiency is estimated in simulation based on practical characterizations. It appears that correct efficiency with a reasonable silicon surface and volume can be reached.

Design and Realization of Highly Integrated Isolated DC/DC Microconverter

Monolithic integration dedicated to power electronics applications simplifies design and implementation of converters This paper presents a simple and highly integrated gate driver powering technique for AC switches and AC to AC converters Gate driver supply operating principle and integration are first recalled Then, it is shown how the proposed solution can easily be implemented into or within AC switches made with two elements or even with double sided switches Finally, it is shown how this gate driver powering technique operates when used in AC to AC converters An experimental set up comes to validate this operation and the overall approach

AC switches with integrated gate driver supplies

To answer the low cost and simplicity necessities for massive market converter applications (home appliance and automotive, for example) and with the help of the monolithic integration, new components have been developed by industry. This approach leads to cost and volume reductions. In the case of intelligent power MOSFETs, the control part is supplied through one supplementary winding, integrated with the flyback converter's inductor. The result is an extra cost and a specific design of passive devices. We propose an original solution to allow permanent and wide-range operations, with no need of any supplementary third coil to power supply the intelligent switch. This solution can be easily integrated in the same substrate within the power switch without special needs for insulation, bringing fairly good results in flyback converter applications based on the use of intelligent switches. In addition, the powering technique is used to clamp the turn-off overvoltage. The global converter's operation takes advantage of the implementation of this new technique.

Jean-Christophe Crebier

Papers

Gate Driver Supply Architectures for Common Mode Conducted EMI Reduction in Series Connection of Multiple Power Devices

A new method for EMI study in boost derived PFC rectifiers

Design and Realization of Highly Integrated Isolated DC/DC Microconverter

AC switches with integrated gate driver supplies

High-Efficiency and Fully Integrated Self-Powering Technique for Intelligent Switch-Based Flyback Converters