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.

/pdf/a-review-of-single-phase-improved-power-quality-ac-dc-2pm6h4zjxq.pdf

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

Switched mode power supplies must comply with electro-magnetic interference (EMI) regulations. Due to technological improvements, switching frequencies have been increased leading to reduced passive component values but also greater EMI levels, especially conducted common mode disturbances. This paper presents a simple and effective EMI forecast method to study and to analyze the conducted EMI effects before prototype testing. The methodology is validated and applied to the single phase full bridge power factor correction (PFC) rectifier. Several techniques to reduce common mode current (CMC) levels created by the converter are presented. The study is based on high frequency models and understanding of phenomenon. Looking at the control strategies and/or the propagation paths, it is demonstrated that EMI levels may be reduced. It is shown that with symmetrical EMI propagation paths, synchronized control strategies such as bipolar pulse width modulation (PWM) are preferred and lead to reduced CMC levels. On the other hand, with asymmetrical propagation paths, unipolar and half bridge control strategies may be preferred to reduce both differential mode current (DMC) and CMC levels. Results are validated using practical experiments performed under EMI regulation testing conditions.

PFC full bridge rectifiers EMI modeling and analysis-common mode disturbance reduction

Interleaved discontinuous conduction mode (DCM) three-phase boost rectifiers provide current ripple cancellation and increase the effective frequency of the input current ripple. As a result, the size and cost of the differential mode (DM) input filter is reduced. This work presents a detailed analysis of the input current ripple of interleaved three-phase DCM boost rectifiers. The design curves derived from the analysis are used to determine the DM input filter parameters. The experimental results are shown for two interleaved three-phase DCM boost rectifiers rated at 8 kW of total power and operated at 40 kHz with IGBTs as the main power switches. The results show that the interleaved rectifiers comply with the IEC 61000-3-2 Class A harmonic standard for this power level.

Interleaved three-phase boost rectifiers operated in the discontinuous conduction mode: analysis, design considerations and experimentation

This study deals with power MOSFET models Parasitic capacitances are one of the main parameters for dynamic models, and have a critical influence on switching waveforms and switching losses Most classical models consider that these capacitances are only mono-voltage dependent, but these models do not take into account the two (drain and gate) voltage influences on parasitic capacitances values, and consequently on switching behavior Therefore simulation results have not been properly estimated, especially for switching losses This aspect may appear critical for driver design or integration perspectives Moreover, manufacturers' datasheets offer a description of these capacitances out of nominal operation; this kind of data is not sufficient to build an accurate dynamic model of the component In this paper, we show the inadequacy of this kind of model, by referring to a physical structure analysis of charge locations during switching transitions Next, the article presents a new insight based on this approach Firstly, we describe the analytical equations ruling this model with respect to critical voltage changes After an experimental parameter extraction under nominal operation, our empirical model is established and implanted in the PSPICE simulator Its topology allows the modeling of both voltages-depending nonlinear capacitances to be taken into account The complete model is tested on components from various manufacturers, and results are compared with experimental curves This model appears to be more accurate and more reliable than PSPICE or manufacturer original models Consequently, this accuracy in switching waveforms is invaluable for driver design It improves switching losses and EMI predictions, and could be used for optimizing the design of drive circuit (eg in applications such as integrated functions) This aspect appears greatly valuable for manufacturers

Power MOSFET switching waveforms: an empirical model based on a physical analysis of charge locations

The paper presents a simple and cost effective solution to supply high side power electronic switch gate drivers. The solution can be integrated and it is demonstrated that it can be loss free, depending on how the power switch is driven. The solution is based on a pulsed linear regulator, only sensitive to a positive dv/dt. At every main power switch's turn OFF, it recycles the switching losses in order to recharge a storage capacitor. The paper presents the global operation and focuses on interesting and important operating characteristics thanks to simulation and practical results.

Loss Free Gate Driver Unipolar Power Supply for High Side Power Transistors

This work presents an overview of single-phase boost-chopper-derived power-factor-correction rectifiers. Converters are presented for several control strategies in continuous and discontinuous current mode operations. The presentation highlights the main characteristics of the converters and underlines harmonic content over a wide frequency range. A methodology is derived to compute these harmonics in order to facilitate the analysis and performance evaluation of the converters. Based on this methodology, a comparison is conducted in order to highlight advantages and drawbacks of the most popular converters and control strategies. A table is given where main converter critical parameters are summarized in order to help the designer, in converter and operating mode selections. Practical results are provided to validate the modeling technique.

Jean-Christophe Crebier

Papers

PFC full bridge rectifiers EMI modeling and analysis-common mode disturbance reduction

Interleaved three-phase boost rectifiers operated in the discontinuous conduction mode: analysis, design considerations and experimentation

Power MOSFET switching waveforms: an empirical model based on a physical analysis of charge locations

Loss Free Gate Driver Unipolar Power Supply for High Side Power Transistors

Boost-chopper-derived PFC rectifiers: interest and reality