[Show abstract][Hide abstract] ABSTRACT: Decades of research have seen single-phase boost-type pulse-width modulation converters be employed as front-end power factor correction (PFC) rectifiers in commercial power supplies. The benefits of employing this technology to comply with power quality standards while assuring high efficiency, low volume, and weight have been observed. However, this paper shows that further efforts can be driven toward new topologies. In this context, novel single-phase rectifier circuits are introduced. These are able to double or triple the ripple frequency present at the input components. Furthermore, a high utilization of the switches is observed during both positive and negative grid half-cycles. The theoretical analysis of the proposed topologies as well as their operation in PFC applications are presented and different operation modes are proposed and a comparison with a state-of-the-art PFC rectifier is presented. Finally, experimental verification of a PFC rectifier doubling the switching frequency is presented in a 1-kW prototype employing a current self-control strategy.
IEEE Transactions on Power Electronics 01/2014; 29(11):5749-5760. · 4.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This work presents an automated design procedure for series parallel resonant converters (LCC) employed in electrostatic precipitator (ESP) power supplies, which reduces the designer effort significantly. The requirements for the power supplies in ESP applications and means to derive an accurate mathematical model of the LCC converter, such as the power loss from commercial insulated-gate bipolar transistors, are described in detail in this paper. The converter parameters, such as resonant tank elements, are selected in order to improve the overall efficiency of the system, when a typical ESP energization operation range is considered. The analysis comprises two different control strategies: the conventional variable frequency control and the dual control. Both control strategies are analyzed by comparing semiconductor losses of five commercial modules. Finally, the circuit operation and design are verified with a 60 kW LCC resonant converter test setup.
[Show abstract][Hide abstract] ABSTRACT: This paper presents highly efficient three-phase high-power-factor hybrid rectifiers assembled by the parallel connection of a three-phase diode-bridge rectifier and series dc-dc boost converter with a two- or three-level unidirectional pulse width modulation (PWM) rectifier. The idea is to obtain a rectifier that is robust, highly efficient, and simple as a diode-based rectifier and also able to benefit from the PWM rectifier capability to reduce the line current harmonic content. Exemplary three-phase unidirectional hybrid systems built with a two-level delta-switch rectifier and three-level T-type or VIENNA six-switch rectifiers are suggested. Additionally, control schemes, which are appropriate for safeguarding the high-power-factor operation while improving the power sharing rating of the hybrid paralleled rectifier units and able to handle a phase loss without changing the controller structure, are proposed. In order to evaluate the studied hybrid rectifiers, first, an efficiency comparison between two- and three-level hybrid systems with conventional PWM rectifiers is performed. After that, the loss calculations are extended to a variable chip area to allow a fair comparison between these rectifiers. Interestingly, it is shown that the presented hybrid systems not only can achieve a higher efficiency but also require less silicon area than the single PWM rectifiers they are based on. Finally, experimental results obtained with an assembled unidirectional hybrid delta-switch rectifier prototype are presented in order to demonstrate the performance and advantages of this solution.
[Show abstract][Hide abstract] ABSTRACT: In this paper, a three-phase buck-type unity power factor rectifier is designed for high-power electric vehicle battery charging mains interfaces. The characteristics of the converter, named the Swiss Rectifier (SR), including the principle of operation, modulation strategy, suitable control structure, and dimensioning equations are described in detail. Exemplarily, a 7.5 kW hardware prototype is then designed based on the derived analytical expressions and the feasibility of the SR concept is demonstrated by the means of experimental measurements. Finally, the SR is compared with a conventional six-switch buck-type ac–dc power conversion. According to the results, the SR is the topology of choice for a buck-type PFC.
IEEE Transactions on Power Electronics 04/2013; 28(4):1608-1621. · 4.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This work proposes novel three-phase ac-ac indirect matrix converter (IMC) topologies well-suited for voltage step-up operation, e.g. wind energy generation applications. The IMC systems employ a bidirectional delta-switch voltage source converter (VSC) as front-end stage and a bidirectional current source converter (CSC) as the back-end grid connected converter. Two space vector modulation schemes for the studied ac-ac converter featuring commutations under zero current or zero voltage are presented. Finally, in order to demonstrate the advantages of the new delta-switch IMC (Δ-IMC), a comparison of the proposed solution and conventional IMC rated to 10 kW is given for a permanent magnet synchronous generator based wind power system.
Industrial Technology (ICIT), 2013 IEEE International Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This paper discusses new three-phase ac-ac Indirect Matrix Converter (IMC) topologies featuring higher power efficiency than conventional IMCs. Initially, a new Inverting-link Matrix Converter (ILMC) with lower conduction power losses than a standard ILMC for voltage step-down operation is proposed. New Ultra-Sparse Matrix Converters (USMCs) well-suited for voltage step-down applications are also presented. These circuits have redundant current paths to distribute the impressed dc-link current to the input terminals which can be potentially used to reduce semiconductor losses. A voltage step-up USMC, referred to as delta-switch USMC (Δ-USMC), well-suited for wind power generation systems, where low inductance machines are used, is also analyzed. In order to benefit from the best features of the proposed IMCs, standard and new space vector modulations featuring distinctive commutation schemes are presented. Finally, to demonstrate the advantages of the studied IMCs, power loss comparisons of these solutions and standard IMCs rated to 10 kW are shown.
Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This work introduces a new three-phase buck-type unity power factor converter appropriate to act as an interface between a residential DC power distribution and the three-phase AC grid. The AC-to-DC power converter is constructed with a conventional six-switch buck-type PFC converter and an integrated current inverting-link circuit. The characteristics of this circuit, including dimensioning formulas, appropriate modulation and control structure, are described in this paper. Simulation results are used to validate the circuit operation and to verify the accuracy of the converter power loss model developed.
Energy Conversion Congress and Exposition (ECCE), 2013 IEEE; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This paper discusses a three-phase high-power factor five-level buck- + boost-type converter well-suited for acting as interface between residential DC power distribution systems and the AC grid. The power converter is constructed with two phase-shift modulated six-switch buck-type PFC converters, efficiently paralleled across their DC-link by inter-phase transformers, and a voltage and/or current inverting switching section. Accordingly, the system features: bidirectional current carrying capability; relatively low semiconductor part count; high utilization of the power semiconductors; and low current and voltage ripples at the input and output terminals. The characteristics of this topology, including the principles of operation, modulation strategy, and dimensioning equations are described in this paper. The feasibility of the presented converter is demonstrated by means of a constructed hardware prototype.
Industrial Technology (ICIT), 2013 IEEE International Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This paper presents the design and implementation of a three-phase high power factor mains interface concept appropriate for many power electronic applications such as supplies for dc power distribution systems in telecommunication, electric vehicle battery charging, future more electric aircraft, variable-speed ac drives, and high power lighting systems. The circuit topology comprises a buck-type power factor correction rectifier circuit built by the combination of an active third-harmonic injection rectifier and a series-connected dc-dc buck-type converter. The characteristics of this rectifier topology, including the principles of operation, modulation strategy, suitable control structure, and dimensioning equations, are described in this paper. The feasibility of the presented converter for buck-type rectifier applications is demonstrated by means of a constructed hardware prototype.
IEEE Transactions on Power Electronics 01/2013; 28(1):7-13. · 4.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper presents highly efficient three-phase unidirectional buck-type unity power factor rectifiers well-suited for various power electronic applications such as high power EV battery charging or DC distribution systems. The circuits are assembled by incorporating two auxiliary circuit branches into standard three-phase buck-type PFC topologies, each one comprising of one active switch and three diodes. This enables redundant current paths for distributing the impressed output DC currents to the AC input terminals, which can be potentially used to reduce the system's total semiconductor losses and/or increase its output power capability. The advantages of a new converter constructed with a three-phase six-switch buck-type PFC, including the principles of operation, modulation strategy and suitable control structure are described in this paper. Finally, the proposed converter is compared with the conventional six-switch buck-type converter and SWISS rectifier. According to the results, the studied AC-to-DC system is the topology of choice for a buck-type PFC.
Industrial Electronics Society, IECON 2013 - 39th Annual Conference of the IEEE; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This paper introduces a novel three-level voltage-source converter (VSC) as an alternative to known three-level topologies, including the conventional neutral-point-clamped converter (NPCC), many T-type VSCs, and active NPCC. It is shown that, operating in the low converter dc-link voltage range, this new solution not only can achieve higher efficiency than many typical three-level structures but also can overcome their drawback of asymmetrical semiconductor loss distribution for some operating conditions. Therefore, a remarkable increase of the converter output power capability and/or system reliability can be accomplished. The switching states and commutations of the converter, named here as hybrid NPCC (H-NPCC), are analyzed, and a loss-balancing scheme is introduced. Five- and seven-level H-NPCC topologies with loss-balancing features are also presented. Finally, a semiconductor-area-based comparison is used to further evaluate many three-level VSC systems. Interestingly, the total chip area of the proposed H-NPCC is already the lowest for low switching frequencies.
[Show abstract][Hide abstract] ABSTRACT: This work presents a new multilevel unidirectional single-phase PFC rectifier topology well-suited for applications targeting for high efficiency and/or high power density. The characteristics of this rectifier topology, including the principles of operation, modulation strategy, feedback control scheme, and dimensioning equations are described in this paper. Finally, a 3 kW laboratory prototype is constructed and used in order to verify the characteristics of the new converter.
Power Electronics and Applications (EPE), 2013 15th European Conference on; 01/2013
[Show abstract][Hide abstract] ABSTRACT: This paper presents the analysis, design, and experimental performance verification of a serial type line conditioner. Since it processes only a fraction of the load power, the overall converter losses tend to be lower and the efficiency of the conditioner higher. Regarding the dynamic performance, the line inductance, which results in a positive zero in the transfer function of the plant, is taken into consideration when designing a voltage controller with higher bandwidth for faster response. In addition, a virtual resistance is included in the control of the system to damp oscillations often seen for operations at light load and with nonlinear load conditions. Experimental results obtained with a 10 kVA prototype of a serial line conditioner fed from the load side and the proposed feedback control scheme are presented to demonstrate the superior performance of the line conditioner.
IEEE Transactions on Industrial Electronics 02/2012; · 6.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This paper discusses novel three-phase high power factor mains interfaces appropriate for Electric Vehicle (EV) battery charging systems. Initially, a highly efficient two-stage ac-dc system, consisting of a three-phase line-commuted rectifier combined with a three-phase shunt connected Active Power Filter (APF) and a group of interleaved dc-dc buck converters operating in Triangular Current Mode (TCM), is presented. In order to replace the costly APF circuit of the front-end converter, while maintaining PFC capability at the input and allowing similar operating conditions for the back-end dc-dc converter, a rectifier topology employing an active third harmonic current injection circuit is proposed. In addition, a novel three-phase buck-type PFC rectifier is introduced for EV charging systems. The characteristics of the presented EV systems, including the principle of operation, modulation strategy, suitable control structures, and dimensioning equations, are described in detail. Finally, a comprehensive comparison of the studied converters rated to 12kW is shown.
[Show abstract][Hide abstract] ABSTRACT: This paper introduces a novel three-phase buck-type unity power factor rectifier appropriate for high power Electric Vehicle battery charging mains interfaces. The characteristics of the converter, named the Swiss Rectifier, including the principle of operation, modulation strategy, suitable control structure, and dimensioning equations are described in detail. Additionally, the proposed rectifier is compared to a conventional 6-switch buck-type ac-dc power conversion. According to the results, the Swiss Rectifier is the topology of choice for a buck-type PFC. Finally, the feasibility of the Swiss Rectifier concept for buck-type rectifier applications is demonstrated by means of a hardware prototype.
[Show abstract][Hide abstract] ABSTRACT: This paper discusses three-phase bidirectional high-power factor mains interfaces for application in smart-houses featuring a local DC distribution grid. The DC grid demanded power can be supplied by local DC generators, such as renewable power sources, and/or by the public three-phase AC mains, which gives the option of feeding back power into the mains in case of a low local power consumption. In order to generate a local 400V DC bus, bidirectionally connected to the European three-phase low voltage AC mains rated at 400V line-to-line, buck-type converter topologies are required. Several possible converter concepts are initially presented and further comparatively evaluated based on the following performance indices: total required semiconductor chip area, overall efficiency, overall passive components volume, and required EMI filter damping. As result of the comprehensive evaluation, the Bidirectional 3rd Harmonic Injection Active Filter Type Rectifier with DC/DC Output Stage is identified as most advantageous topology for the realization of a bidirectional buck-type PFC rectifier in the considered power range of 5 to 10 kW.
[Show abstract][Hide abstract] ABSTRACT: In this article, the distortions caused by the power supplies employed in Electrostatic Precipitators (ESP) are investigated, and means for improving the line power quality are proposed. Multi-pulse and PWM rectifier topologies and other concepts including hybrid systems and active filters are evaluated in order to identify suitable systems for ESP applications. A comparison of the studied systems rated to 60 kW and fully designed employing commercial components is shown. The ESP systems efficiency, power density, current harmonic THD, among others features are used for the assessment. The loss calculations are extended to a variable chip area to allow a fair comparison between the studied systems. Finally, the VIENNA 6-switches rectifier and active filter concepts are chosen and experimental analyses are carried out, verifying the performance and feasibility of the proposed systems.
Power Electronics and ECCE Asia (ICPE & ECCE), 2011 IEEE 8th International Conference on; 07/2011
[Show abstract][Hide abstract] ABSTRACT: The focus of this paper is the study of direct alternating-current (ac)-ac converters, beginning by buck, half-bridge, full-bridge, and push-pull converters. From the basic converters, we apply a simple methodology to make the use of switches in commercial configurations possible. Following that, eight voltage restorers supplied either on the line side or on the load side are proposed. A comparative evaluation of these topologies concerning implementation, complexity, and component effort is presented. It is notable that some of the studied topologies are known in the literature and others are new. For one of the presented topologies, the design of a 3-kVA voltage restorer is developed, and experimental results are shown, certifying the correct operation of the drive strategy used.
IEEE Transactions on Industrial Electronics 02/2011; · 6.50 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In this paper an efficiency comparison between 3-phase shunt active filters derived from the 2-level VSC, the 3-level NPC, Active NPC (A-NPC) and the T-type VSC is presented. In order to address the loss distribution issue of the 3-level topologies, while keeping the efficiency of the system high, a space vector modulation scheme incorporating a special clamping of the phase is proposed. It is shown that 3-level active filters can have their losses well distributed over the chip dies, leading to only a small difference in their operating temperatures. Additionally, a semiconductor area based comparison is used to further evaluate the studied active filter systems. Finally, experimental results obtained with a 12kVAr/48kHz 3-level NPC based shunt active filter employing custom SiC power modules are presented in order to demonstrate the performance and feasibility of this solution.