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Power converter design evaluation by means of real-time simulation techniques is prevalent, although it is mostly restricted to simple power semiconductor switch models that exclude device-level physical details. In this work, the nonlinear high order electrothermal model of the IGBT is developed and then deployed onto the heterogeneous digital hardware for real-time implementation. As the complexity of the NBM of the IGBT poses a significant computational burden on real-time hardware emulation, ML methodology is utilized so that the trained model can reproduce the characteristics of its original counterpart as much as possible and then it is implemented on the ACAP, which composes of the PS, PL, and AIE. The vector multiplication feature of the AIE caters to mathematical operations of theML-based model particularly well and consequently enables it to be executed in real-time with remarkable speedup over the original model with which matrix inversion is otherwise mandatory. Finally, the validation for real-time device-level results and system-level results of a multiconverter system is provided by SaberRD and MATLAB/Simulink.

The structure and behaviour of electrical grids are rapidly changing due to the increasing grid integration of inverter-based resources (IBRs) and the adoption of electric vehicles in low-voltage distribution grids. The changes emphasize the need for a holistic modification of methods used in modeling and simulating power systems. The electromagnetic transients (EMT) simulations based on detailed switching time-domain models, represent the true dynamics of power systems and converters. However, EMT simulations require long execution times. With the increasing integration of IBRs in the power system, static phasor-type simulations may be inaccurate because of reduced system inertia and strong interaction of the control schemes of IBRs with line dynamics. The dynamic phasor (DP) method is an alternative method to develop computationally efficient and accurate power system models. The DP method gives the user the freedom to select dominant harmonics and dynamics to model which in turn, enables the use of large step sizes to accelerate simulations. In the literature, little attention has been paid to DP-based modeling of single-phase low-voltage systems. Considering the upsurge in the deployment of residential microgrids, developing robust and well-validated DP models of single-phase power converters and microgrids is pertinent. This thesis augments the library of DP models by extending the DP method to the modeling of nonlinear (Lyapunov) and linear controller-based single-phase grid-following and grid-forming inverters, H-bridge active rectifiers, droop-controlled microgrids, diode-bridge rectifiers, and non-isolated DC-DC converters. Additionally, this thesis proposes the DP model of a synchronization unit suitable for (re)connecting a grid-forming inverter to a microgrid. To ensure that the proposed DP models have similar dynamic and steady-state responses as the detailed switching models, this thesis proposes a methodological approach of developing small-signal and large-signal DP models for control design purposes. The fidelity of the proposed DP models are validated with experimental and detailed switching model results. Simulation results confirm the high fidelity of the proposed DP models to produce results with comparable accuracy as the detailed switching models while using less simulation execution time. The proposed DP models will be useful to researchers and engineers interested in conducting fast-paced and accurate study of power electronics-dominated low-voltage grids.

A Pulse Width Modulation method is presented in this paper for the harmonics and circulating current reduction in the power converters system. The power converter considered for this research work is a boost converter connected in an interleaved topology in a single setup. The Common-Mode Circulating Current CMCC are studied in detail in this interleaved topology setup. For the Differential-Mode Circulating Current DMCC, these two identical interleaved setups are then connected in parallel. A PWM control method is suggested for harmonic elimination and control of circulating currents inside the circuit. This method results are compared with Feed Forward and AICMC control methods. Simulation results are presented to show the effectiveness of this proposed model.

This study investigates the field-weakening capability of interior permanent magnet (IPM) and surface-mounted permanent magnet (SPM) machines with distributed windings by considering phase voltage distortion in field-weakening region. For analysis and comparison, the Nissan Leaf vehicle traction machine is studied as a reference benchmark machine and then a comparable SPM machine is designed within the main constraints of the benchmark machine. A finite element analysis model of the benchmark machine is developed and validated by published experimental measurement. Sinusoidal phase current is desired to enhance machine torque performance and power electronic converters employing vector control method are commonly used for traction machine supply. However, the machine terminal phase voltage distortion may introduce additional difficulties for machine control. Therefore, firstly, phase voltage distortions of IPM and SPM machines with distributed windings are compared and the mechanisms are discussed. Due to the voltage distortion, the peak value of phase voltage may be higher than the fundamental one. Therefore, the influences of IPM and SPM topologies on machine traction characteristics are investigated. The study indicates that SPM machines with distributed windings can be designed to achieve comparable torque and power performance and better field-weakening capability compared to IPM machines.

Power electronic converters have been widely used in power system and the stability issues of DC microgrid with converters will be discussed in this study. Firstly, an equivalent circuit and the corresponding state space model for DC microgrid with DC–DC converters were established. The model shows that the DC microgrid systems with DC–DC bidirectional converter in boost or buck mode is a non-linear system, and the tightly regulated point-of-load converters may destabilise the system because it introduces negative incremental resistance to DC microgrid. Then the method of exact feedback linearisation, which transforms the non-linear system into the linear system by coordinate transformation, was applied to stabilise DC microgrid system, and the stabilisation strategy of non-linear system was determined by designing the feedback coefficient of the linearised system. Finally, the feasibility and effectiveness of the stabilisation strategy for DC microgrid with DC–DC bidirectional converter have been verified by the results of simulation with MATLAB.

The quest for a green electrical power system has increased the use of renewable energy resources and power electronic converters in the existing power system. These power electronic converters, however, are a major cause of harmonics and result in the degradation of power quality. In the last two decades, researchers have proposed various designs of multilevel converters to minimize these harmonic distortions, however, a comprehensive solution for stand-alone solar photovoltaic (PV) systems with low total harmonic distortion (THD) is still missing in the present body of knowledge. This paper proposes a single-phase 17-level cascaded H-bridge multilevel converter (CHMC) model for a stand-alone system using solar PV arrays. The proposed model employs eight different flexible PV arrays that can be replaced with DC voltage sources when required to meet the load demand. The proposed model does not include any capacitor and filter thus saving a lot of cost in the overall system. The model has been implemented in the Simulink environment using a model-based design approach. The simulation results show that the proposed model has reduced the THD to almost 7% as compared to the existing models. The cost comparison of the proposed converter also proved its economic benefit over other types.

In Part I, a method for the Harmonic Power-Flow (HPF) study of three-phase power grids with Converter-Interfaced Distributed Energy Resources (CIDERs) is proposed. The method is based on generic and modular representations of the grid and the CIDERs, and explicitly accounts for coupling between harmonics. In Part II, the HPF method is validated. First, the applicability of the modeling framework is demonstrated on typical grid-forming and grid-following CIDERs. Then, the HPF method is implemented in Matlab and compared against time-domain simulations with Simulink. The accuracy of the models and the performance of the solution algorithm are assessed for individual resources and a modified version of the CIGR\'E low-voltage benchmark microgrid (i.e., with additional unbalanced components). The observed maximum errors are 6.3E-5 p.u. w.r.t. voltage magnitude, 1.3E-3 p.u. w.r.t. current magnitude, and 0.9 deg w.r.t. phase. Moreover, the scalability of the method is assessed w.r.t. the number of CIDERs and the maximum harmonic order ($\leqslant$25). For the maximum problem size, the execution time of the HPF method is 6.52 sec, which is 5 times faster than the time-domain simulation. The convergence of the method is robust w.r.t. the choice of the initial point, and multiplicity of solutions has not been observed.

Nowadays, applications of advanced power electronic technology enable producing an AC supply with a phase number higher than three-phase. Five-phase voltage source inverters (5Ph-VSI) have been used in advanced power electronic drives to improve the reliability of the drive system and to boost the power capability of the converter as well as to their other inherent merits. This paper shows the mathematical analysis and simulation of the third harmonic injection-pulse width modulation (THI-PWM) 5Ph-VSI connected with inductive load in three scenarios i.e. star, pentagon and pentacle. The presented THI-PWM technique for a 5Ph-VSI aims to increase the inverter fundamental voltage and hence to maximize the utilization of DC bus without causing over-modulation. The simulation results are compared with typical sinusoidal pulse width modulation (SPWM) and the 10-step mode operation. The proposed scheme may be considered as a compromise case between the two references cases; as low harmonic components compared with 10-step mode operation and a high utilization factor compared with SPWM.

Recently, emerging sub-/super-synchronous oscillation (SSO) issues occurred in large-scale wind power systems, which are caused by the interactions between the power electronic converter based wind turbine generators (WTGs) and the ac/dc grids. In previous studies, the practical system is usually simplified to equivalent system models, which consist of a (several) large-capacity WTGs connected to a radial equivalent line. However, such equivalent models can hardly represent the dynamics of the practical large-scale wind systems. Besides, the impacts on SSO characteristics from such important factors as network topology, steam turbine generators, and high-voltage direct currents have not been clarified yet. To deal with these challenges, this paper proposes a systematic impedance network modeling and quantitative stability analysis method. All system components of the large-scale wind systems are represented with impedance models (IMs) in a unified reference frame, and then, they are interconnected based on the system topology to form the impedance network model (INM) of the whole system. With the INM reduced to an aggregated IM, a stability criterion is developed to assess SSO stability just by analyzing the frequency characteristics of the determinant of the aggregated IM, and a quantitative analysis method is proposed to quantify the damping, frequency, and sensitivity of the SSO mode. The electromagnetic transient simulations on a practical wind system, which suffered actual SSO issues, have validated the effectiveness and accuracy of the proposed method. This paper also conducts comparative analysis on four types of popular stability analysis methods to show the advantages of the proposed method.

Solid-state transformers (SSTs) have emerged as a superior alternative to conventional transformers and are regarded as the building block of the future smart grid. They incorporate power electronics circuitry and high-frequency operation, which allows high controllability and enables bi-directional power flow, overcoming the limitations of conventional transformers. This paper presents a detailed analysis of the solid-state transformer, expounding the fundamentals, converter topologies, applications, and future challenges of the SST in a systematic manner. The paper discusses the necessity of improved replacement of the low-frequency transformers (LFTs) and presents the configuration of SST. It presents SST fundamentals in individual stages and explores its origin and evolution. The basic topologies, their specifications, and control strategies are also described. The applications of SST as a replacement of LFTs are discussed along with recent applications. The future challenges for real-time implementation of SSTs are explored, and research directions are proposed.

The increasing wind power penetration poses a great challenge to the operation stability of the traditional power system. The current mainstream wind turbines are variable speed wind turbines. Some of the traditional power supplies are replaced by large-scale wind power integration. The inertia of a variable speed wind turbine is decoupled by power electronic converters from the power network and therefore does not intrinsically contribute to power system inertia. The principle of the power system frequency regulation is introduced. The primary frequency response of the high wind penetration power system is analysed based on a typical power system frequency response model and the primary frequency characteristic of the wind turbine. Necessary primary reserves provided by wind farms are studied based on the real data of a specific power system.

A conventional electrical grid mostly depends on the electrical power generated from fossil fuels. However, the pollutants from fossil fuels are the key factors for adverse climate change. Most of the developed countries of the world have already recognized the fact that the energy mix requires to be diversified by incorporating renewable energy. This is especially relevant for many of the member countries of the Organization of Islamic Cooperation (OIC), consisting of 57 countries, whose abundance of fossil fuel reserve indicates that much of their electric power is still generated from fossil fuels. In order to integrate renewable energy sources into the hybrid energy mix, an existing conventional grid needs to undergo drastic changes. Alongside this, the population boom in the OIC member countries has caused higher demand for a steady supply of electricity that the conventional grids have long been struggling to cope with. With a view to solving this multifaceted problem, incorporation of the smart power management schemes is indispensable using a smart electrical grid, where information and communications technology is integrated into its major building blocks. This allows advanced applications of a grid, such as the formation of micro-grids, demand-side management, energy storage, high-tech power electronic converters, etc. As the smart grids are being adopted by many developed countries, it is high time for the OIC member countries to pay due attention to this development, if they have not already done so. This paper explains, with special focus on the OIC member countries, the various smart power management technologies, their operations and applications, and the benefits and challenges. Then it goes on to carry out the Strength-Weakness-Opportunity-Threat with Analytical-Heuristic-Procedure (SWOT-AHP) analysis to evaluate its feasibility of incorporation and the underlying strategies appropriate for its implementation. Furthermore, a Hybrid Multi-Criteria-Decision-Making (MCDM) analysis is performed to evaluate the sequence of the emphasis that should be given on each of the technologies from those available for the smart power management initiative. Finally, the study reinforces the stance by drawing parallels from the UN Sustainable Development Goals (SDG) and highlights the importance of the smart grid in line with the global vision of SDG. This paper aims at assisting the decision-makers in implementing smart power management schemes in the OIC member countries, in particular, and other countries of the world, in general.

Electric transportation systems are a challenging load for three-phase transmission lines due to load variations, reactive power, imbalance, and harmonic pollution. Many power quality conditioners and compensation technologies have been developed to ensure compatibility with power systems. The most important ones are investigated, identifying parameters and performances for comparison, including evaluation of cost and size. A reference case is used for simulation, focusing on three-phase current intensity, current rate of rise, dc-link voltage, and dynamic response under various combinations of traction line load. The objective is to identify key characteristics supporting the selection of the appropriate compensation strategy for a new electrified railway system.

Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectric transducer impedance has been discussed in different literatures, the trend of the nonlinearity at different frequencies with respect to excitation voltage variations has not been clearly investigated in practice. In this paper, to demonstrate how the nonlinearity behaves, a sandwich piezoceramic transducer was excited at different frequencies. Different excitation signals were generated using a linear power amplifier and a multilevel converter within a range of 30–200 V. Empirical relation was developed to express the resistance of the piezoelectric transducer as a nonlinear function of both excitation voltage and resonance frequency. The impedance measurements revealed that at higher voltage ranges, the piezoelectric transducer can be easily saturated. Also, it was shown that for the developed ultrasound system composed of two transducers (one transmitter and one receiver), the output voltage measured across receiver is a function of a voltage across the resistor in the RLC branches and is related to the resonance frequencies of the ultrasound transducer.

The paper introduces basic characteristics of the traction drive and the way how modern multi-system traction vehicle can be realized. The main aim of the paper is focused on using single phase matrix converter (1ph MC) as an input converter for medium frequency transformer. The control algorithm for switching of 1ph MC is described in detail and its functionality is verified in simulations and on real laboratory prototype composed of single phase matrix converter and a voltage source active rectifier. This paper describes the suitability of using FPGA and DSP combined algorithms for modular single-phase matrix converters with medium-frequency transformer for traction drive applications.

This paper proposes a novel controllable crowbar based on fault type (CBFT) protection technique for doubly fed induction generator (DFIG) wind energy conversion system connected to grid. The studied system consists of six DFIG wind turbines with a capacity of 1.5 MW for each of them. The operation mechanism of proposed technique is used to connect a set of crowbar resistors in different connection ways via activation of controllable circuit breakers (CBs) depending on the detected fault type. For each phase of DFIG, a crowbar resistor is connected in parallel with a controllable CB and all of them are connected in series to grid terminals. The adaptive neuro-fuzzy inference system (ANFIS) networks are designed to detect the fault occurrence, classify the fault type, activate the CBs for crowbar resistors associated with faulted phases during fault period, and deactivate them after fault clearance. The effectiveness of proposed CBFT protection technique is investigated for different fault types such as symmetrical and unsymmetrical faults taking into account the single-phase to ground fault is the most frequently fault type that occurs in power systems. Also, a comparison between the behaviours of studied system in cases of using traditional parallel rotor crowbar, classical outer crowbar, and proposed CBFT protection techniques is studied. The fluctuations of DC-link voltage, active power, and reactive power for studied system equipped with different protection techniques are investigated. Moreover, the impacts of different crowbar resistance values on the accuracy of proposed technique are studied. The simulation results show that, the proposed technique enhances the stability of studied wind turbine generators and contributes in protection of their components during faults.

With the revolution of renewable energy, the power system is being more complicated and integrated with more and more power electronics, which is referred to as the “power electronized” power system. In this case, the analysis, control, and operation of the entire power system should tone with the energy-paradigm transition pace. This paper thus explores challenges in power electronized power systems and highlights the stability issue. It serves to spark inspiration on potential solutions to these issues. As one of the solutions to cope with the interconnection of power converters with multi-synchronous generator systems, the virtual inertia concept is discussed in this paper. The impact of highly aggregated power electronic-based power systems is presented. More importantly, prospective solutions considering multiple timescales for the enhancement of power electronized power systems are briefed. A case study is exemplified in this paper to further highlight the analysis and discussion.

International audience; This paper presents an Electromagnetic Interferences (EMI) modeling of a DC-AC power converter, based on a black box representation: the converter is represented by an association of sources and impedances that reflect its external EMI behavior. This modeling approach presented in this paper requires a very short computation time, which allows an optimized design of an EMC filter or an interaction study between several converters connected on the same electrical network. This EMC model depending on a given operation point of the converter, the second part of this paper is dedicated to the study of the load influence on this behavioral model.

Since the introduction of finite control set model predictive control (FCS-MPC) in power electronics the algorithm has been missing an important aspect that would speed up its implementation in industry: a simple method to verify the algorithm performance. This paper proposes to use a statistical model checking (SMC) method for performance evaluation of the algorithm applied to power electronics converters. SMC is simple to implement, intuitive and it requires only an operational model of the system that can be simulated and checked against properties. Device under test for control algorithm application in this paper is a standard 2-level voltage source converter (VSC) with LC output filter used for uninterruptible power supply (UPS) systems. The performance of control algorithm is verified using the UPPAAL SMC toolbox and the behavior is compared to simulation results obtained from equivalent MATLAB/Simulink model and measurements from experimental set-up. Performance results are presented in terms of probabilities with corresponding uncertainties for calculated difference between the reference capacitor voltage value and the measured output voltage, and a simple moving average value. Algorithm’s performance is tested with parameter uncertainties introduced in the model as well.

This paper proposes a new short-circuit protection method for an IGBT. The proposed method is characterized by detecting not only gate charge but also gate voltage of the IGBT. This results in a shorter protection time, compared to the previous method that detects only the gate charge. A real-time monitoring system using an FPGA, A/D converters, and a D/A converter is used for the proposed protection method. Experimental results verify that the proposed method achieves a protection time of 390 ns, which is reduced by 68% compared to the previous method., ESREF 2014, 25th EUROPEAN SYMPOSIUM ON RELIABILITY OF ELECTRON DEVICES,FAILURE PHYSICS AND ANALYSIS, Sep 29–Oct 3, 2014, Technische Universität Berlin

This paper describes the resonance introduced by adverse interaction of electronic converters. With the presence of multiple power-electronic converters, situations can occur where the harmonics are amplified due to the interaction between converters. An observation of undamped oscillation leading to instability in a microgrid is described. The term “converter induced resonances” is proposed to describe this phenomenon. The amount of distributed generation, active loads, FACTS and battery energy storage systems are expected to increase in future Smart Grids. All these resources will be interfaced with electronic converters. The potential impact of converter induced resonances in such grids is described. A coordinated design of the control systems of all converters is in practice not feasible. Each device will be independently tested to fulfil grid codes and have its own converter control implemented that can include functionality to modify voltage and /or current waveform. Godkänd; 2014; 20131205 (niceth); Konferensartikel i tidskrift SmartGrid Energilager

Power electronic converters may have a quite long lifetime, but some applications such as converters for automotive and photovoltaic could even desire a longer life. One of the elements to increase the lifetime of converters is to avoid electrolytic capacitors. They can be replaced by metalised film capacitors or ceramic capacitors. A lot of converter types can be re-designed to use them, but it influences the way of designing, as a lower capacitance value is used. Electrolytic capacitors are one of the elements that reduce the lifetime of power electronic converters gradually an adapted design can avoid that electrolytic capacitors have to be used in converters. A range of examples can be shown from fractions of watts up to Gigawatt. The purpose is to give an overview of topologies, not to discussing them in detail: for example gate drive circuits, single and three-phase converters where film capacitors are used in the DC link and high voltage DC converters. These techniques are useful to prolong the life of converters and to allow higher ambient temperatures, typical application domains are PV and other grid connected converters, converters for battery charging and general electric vehicle applications.

The purpose of this review is to provide a survey of some of the most important bifurcation phenomena that one can observe in pulse-modulated converter systems when operating with high corrector gain factors. Like other systems with switching control, electronic converter systems belong to the class of piecewise-smooth dynamical systems. A characteristic feature of such systems is that the trajectory is “sewed” together from subsequent discrete parts. Moreover, the transitions between different modes of operation in response to a parameter variation are often qualitatively different from the bifurcations we know for smooth systems. The review starts with an introduction to the concept of border-collision bifurcations and also demonstrates the approach by which the full dynamics of the piecewise-linear, time-continuous system can be reduced to the dynamics of a piecewise-smooth map. We describe the main bifurcation structures that one observes in three different types of converter systems: (1) a DC/DC converter; (2) a multi-level DC/DC converter; and (3) a DC/AC converter. Our focus will be on the bifurcations by which the regular switching dynamics becomes unstable and is replaced by ergodic or resonant periodic dynamics on the surface of a two-dimensional torus. This transition occurs when the feedback gain is increased beyond a certain threshold, for instance in Electronics 2013, 2 114 order to improve the speed and accuracy of the output voltage regulation. For each of the three converter types, we discuss a number of additional bifurcation phenomena, including the formation and reconstruction of multi-layered tori and the appearance of phase-synchronized quasiperiodicity. Our numerical simulations are compared with experimentally observed waveforms.

This paper describes the development of the power converters and control algorithms to implement an isolated microgrid based in renewable energy sources used to feed a Sustainable Social Centre in a remote place. The microgrid is designed to work with photovoltaic panels, micro wind and micro-hydro turbines, or even with diesel generators. The control system of the power converters is totally digital and implemented by means of a TMS320f28335 Digital Signal Controller (DSC) from Texas Instruments. One of the most im-portant requirements imposed for the microgrid power system is the capability of providing a sinusoidal supply voltage with low harmonic distortion even in the presence of non linear electrical loads. The hardware topologies and the digital control systems of the power converters are evaluated through experimental results obtained with a developed laboratory prototype. This work is focused in the DC AC converter of the renewable energy system for the isolated Sustainable Centre., (undefined)

Accurate thermal dynamics modeling of high power Insulated Gate Bipolar Transistor (IGBT) modules is important information for the reliability analysis and thermal design of power electronic systems. However, the existing thermal models have their limits to correctly predict these complicated thermal behaviors in the IGBTs. In this paper, a new three-dimensional (3D) lumped thermal model is proposed, which can easily be characterized from Finite Element Methods (FEM) based simulation and acquire the thermal distribution in critical points. Meanwhile the boundary conditions including the cooling system and power losses are modeled in the 3D thermal model, which can be adapted to different real field applications of power electronic converters. The accuracy of the proposed thermal model is verified by experimental results.

2016 IEEE Energy Conversion Congress and Exposition (ECCE). 18 Sep - 22 Sep 2016, Milwaukee, WI, USA, This work proposes a non-isolated power electronic topology to interface two distinct electrical energy storage units to a DC link, resulting in a Hybrid Storage System. The proposed solution, called Series-Parallel Connection, allows for interfacing these three ports in a simple, compact and reliable approach, based on the standard configuration of the H-bridge converter. The main advantage is that one of the storage units can be of much smaller voltage ratings than the other two, avoiding the use of multilevel or galvanic-isolated power stages. The resulting structure is compared against the most significant transformerless alternatives based on the H-bridge converter, stating their advantages and drawbacks. An analysis of the switching and conduction losses in the power switches of the proposed solution is carried out in order to state the design constraints at which this solution presents improved efficiency versus the alternatives. A final set of experiments in a 10 kW built prototype demonstrates the feasibility and states the benefits as well as the main limitations of the proposed scheme, This work has been partially supported by the Spanish Government, Innovation Development and Research Office (MEC), under research grant ENE2013-44245-R, Project “Microholo”, and by the European Union through ERFD Structural Funds (FEDER). This work has been partially supported by the government of Principality of Asturias, Foundation for the Promotion in Asturias of Applied Scientific Research and Technology (FICYT), under Severo Ochoa research grant, PA-13-PF-BP13138

International audience; This paper sets forth a sizing optimization methodology of a surface permanent magnet machine-converter system over a torque-speed operating profile. The two optimization objectives are to minimize the cost of the machine-converter system and to minimize (or maximize) electrical energy consumption (or generation). The optimization parameters serve to describe both the machine geometry and the electrical ratings of the electronic power converter. Each operating point of the profile is treated independently, and current control is optimized at every operating point in order to not only minimize machine drive losses but also satisfy several constraints and then implicitly considering flux-weakening possibility. This optimization methodology is generic and is applied to a particular case: a direct-drive conversion chain for a wave energy converter. We show that taking into account both the sizing parameters of the converter and the flux-weakening control, in addition to the classical sizing parameters of the machine, has a strong impact on the machine-converter system optimal results. Moreover, the strong coupling with the wave energy converter through damping parameters, plays also a crucial role on the sizing results.

This paper presents the results of EMI reduction techniques applied to power electronic converters. The techniques applied included shielding control and power signals, separating power system references regarding reference for instrumentation and measurement signals, implementing analog filters and configuring an appropriate switch trigger system for electronic power to decrease shifting EMI emissions to the maximum. This paper presents the results before and after applying the techniques to reduce interference. The results were also veryfied by using two real time control strategies rapid control prototyping (RCP). En este artículo se presentan los resultados de la aplicación de algunas técnicas de reducción de EMI en convertidores electrónicos de potencia. Las técnicas aplicadas incluyen el apantallamiento de señales de control y de potencia, la separación de las referencias del sistema de potencia de las señales y medidas, la implementación de filtros análogos y la configuración de un adecuado sistema de disparo, de tal forma que se disminuyan al máximo las emisiones tipo IEM. En este artículo se presentan los resultados obtenidos antes y después de aplicar las técnicas de reducción de interferencias. Además los resultados son verificados usando dos técnicas de control en tiempo real RCP (Rapid Control Prototy- ping).

This paper proposes a technique for the power flow control of three-phase four-wire low-voltage power systems, that aims at compensating the reactive and unbalance current terms measured at the point of common coupling of microgrids. It is based on a master/slave control architecture where a grid-interactive inverter, installed at the point of coupling between utility and microgrid, acts as master unit while the distributed energy resources act as slave units, allowing to fully exploit their available power capability. The proposed control technique ensures high power quality, smooth power exchange with the utility, and prompt and seamless transitions between grid-connected and islanded operation. The paper introduces the considered system architecture, overviews the power theory underpinning the control approach, and describes the proposed control technique. Finally, a real three-phase distribution system is considered as case study in simulation; the obtained performances in improving the overall power quality are reported and commented, in particular for what concerns the compensation of reactive and unbalance current terms under sinusoidal/symmetrical and nonsinusoidal/asymmetrical voltage conditions.

Orientadores: José Antenor Pomilio, Fernando Pinhabel Marafão Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Engenharia Elétrica e de Computação Resumo: Esta tese apresenta uma possível arquitetura e sua respectiva estratégia de controle para microrredes de baixa tensão, considerando-se a existência de geradores distribuídos pela rede. A técnica explora totalmente a capacidade dos geradores distribuídos em ambos os modos de operação: conectado à rede e ilhado. Quando conectado à rede, sob o modo de otimização global, o controle busca a operação quase ótima da microrrede, reduzindo as perdas de distribuição e os desvios de tensão. Quando em modo ilhado, a técnica regula de forma eficaz os geradores distribuídos disponíveis, garantindo a operação autônoma, segura e suave da microrrede. A estratégia de controle é aplicada a uma estrutura de microrrede completamente despachável, baseada em uma arquitetura de controle mestre-escravo, em que as unidades distribuídas são coordenadas por meio do recém-desenvolvido algoritmo Power-Based Control. As principais vantagens da arquitetura proposta são a expansividade e a capacidade de operar sem sincronização ou sem conhecimento das impedâncias de linha. Além disso, a microrrede regula as interações com a rede por meio do conversor chamado de Utility Interface, o qual é um inversor trifásico com armazenador de energia. Esta estrutura de microrrede permite algumas vantagens como: compensação de desbalanço e reativo, rápida resposta aos transitórios de carga e de rede, e suave transição entre os modos de operação. Em contrapartida, para compartilhar a potência ativa e reativa proporcionalmente entre as unidades distribuídas, controlar a circulação de reativos, e maximizar a operação, a comunicação da microrrede requer em um canal de comunicação confiável, ainda que sem grandes exigências em termos de resolução ou velocidade de transmissão. Neste sentido, foi demonstrado que uma falha na comunicação não colapsa o sistema, apenas prejudica o modo de otimização global. Entretanto, o sistema continua a operar corretamente sob o modo de otimização local, que é baseado em um algoritmo de programação linear que visa otimizar a compensação de reativos, harmônicos e desbalanço de cargas por meio dos gerador distribuído, particularmente, quando sua capacidade de potência é limitada. Esta formulação consiste em atingir melhores índices de qualidade de energia, definidos pelo lado da rede e dentro de uma região factível em termos de capacidade do conversor. Baseado nas medições de tensão e corrente de carga e uma determinada função objetiva, o algoritmo rastreia as correntes da rede ótima, as quais são utilizadas para calcular os coeficientes escalares e finalmente estes são aplicados para encontrar as referências da corrente de compensação. Finalmente, ainda é proposta uma técnica eficiente para controlar os conversores monofásicos conectados arbitrariamente ao sistema de distribuição trifásico, sejam conectados entre fase e neutro ou entre fase e fase, com o objetivo de compensar o desbalanço de carga e controlar o fluxo de potência entre as diferentes fases da microrrede. Isto melhora a qualidade da energia elétrica no ponto de acoplamento comum, melhora o perfil de tensão nas linhas, e reduz as perdas de distribuição. A arquitetura da microrrede e a estratégia de controle foi analisada e validada através de simulações computacionais e resultados experimentais, sob condições de tensão senoidal/simétrica e não-senoidal/assimétrica, avaliando-se o comportamento em regime permanente e dinâmico do sistema. O algoritmo de programação linear que visa otimizar a compensação foi analisado por meio de resultados de simulação Abstract: This thesis presents a flexible and robust architecture and corresponding control strategy for modern low voltage microgrids with distributed energy resources. The strategy fully exploits the potential of distributed energy resources, under grid-connected and islanded operating modes. In grid-connected mode, under global optimization mode, the control strategy pursues quasi-optimum operation of the microgrid, so as to reduce distribution loss and voltage deviations. In islanded mode, it effectively manages any available energy source to ensure a safe and smooth autonomous operation of the microgrid. Such strategy is applied to a fully-dispatchable microgrid structure, based on a master-slave control architecture, in which the distributed units are coordinated by means of the recently developed power-based control. The main advantages of the proposed architecture are the scalability (plug-and-play) and capability to run the distributed units without synchronization or knowledge of line impedances. Moreover, the proposed microgrid topology manages promptly the interaction with the mains by means of a utility interface, which is a grid-interactive inverter equipped with energy storage. This allows a number of advantages, including compensation of load unbalance, reduction of harmonic injection, fast reaction to load and line transients, and smooth transition between operating mode. On the other hand, in order to provide demand response, proportional power sharing, reactive power control, and full utilization of distributed energy resources, the microgrid employs a reliable communication link with limited bit rate that does not involve time-critical communications among distributed units. It has been shown that a communication failure does not jeopardize the system, and just impairs the global optimization mode. However, the system keeps properly operating under the local optimization mode, which is managed by a linear algorithm in order to optimize the compensation of reactive power, harmonic distortion and load unbalance by means of distributed electronic power processors, for example, active power filters and other grid-connected inverters, especially when their capability is limited. It consists in attain several power quality performance indexes, defined at the grid side and within a feasible power region in terms of the power converter capability. Based on measured load quantities and a certain objective function, the algorithm tracks the expected optimal source currents, which are thereupon used to calculate some scaling coefficients and, therefore, the optimal compensation current references. Finally, the thesis also proposes an efficient technique to control single-phase converters, arbitrarily connected to a three-phase distribution system (line-to-neutral or line-to-line), aiming for reduce unbalance load and control the power flow among different phases. It enhances the power quality at the point-of-common-coupling of the microgrid, improve voltage profile through the lines, and reduce the overall distribution loss. The master-slave microgrid architecture has been analyzed and validated by means of computer simulations and experimental results under sinusoidal/symmetrical and nonsinusoidal/asymmetrical voltage conditions, considering both the steady-state and dynamic performances. The local optimization mode, i.e., linear algorithm for optimized compensation, has been analyzed by simulation results Doutorado Energia Elétrica Doutor em Engenharia Elétrica FAPESP 2012/24309-8, 2013/21922-3

This thesis provides insight into quantitative accuracy assessment of the modeling and simulation of power electronic converters. Verification, Validation, and Uncertainty quantification (VVandUQ) provides a means to quantify the disagreement between computational simulation results and experimental results in order to have quantitative comparisons instead of qualitative comparisons. Due to the broad applications of modeling and simulation in power electronics, VVandUQ is used to evaluate the credibility of modeling and simulation results. The topic of VVandUQ needs to be studied exclusively for power electronic converters. To carry out this work, the formal procedure for VVandUQ of power electronic converters is presented. The definition of the fundamental words in the proposed framework is also provided. The accuracy of the switching model of a three-phase Voltage Source Inverter (VSI) is quantitatively assessed following the proposed procedure. Accordingly, this thesis describes the hardware design and development of the switching model of the three-phase VSI. Master of Science

M.Ing. (Electrical and Electronic Engineering) In order to increase the overall performance and reduce the cost of power electronic converters, a new technology for the manufacturing of such converters is needed. The aim of this work is to investigate the possibility of the application of planar integrated manufacturing technology, to power electronic converters. A proposal of the definitions, terminology and graphical representation of the integrated structure is discussed together with some examples. A zero-voltage-switching PWM DC-DC converter is used as a case study. A conventionally constructed converter, using conventional component technology is designed and constructed, after a complete mathematical analysis of the converter topology. A similar converter is designed and constructed using the planar integrated manufacturing technology. Full design details and procedures are given for both converters. The two manufacturing technologies are then compared from the point of view of electrical performance, as well as some other aspects.

In use far and wide for improved delivery and control of the electricity supply, power electronics systems are both the cause and remedy of the power system harmonic pollution problem. Here, the authors describe how an insidious side-effect of any solution involving power electronics converters is their generation of high-frequency pollution-namely, conducted and radiated noise in the 100 kHz to 100 MHz range-which can have an adverse effect on the operation of surrounding electronic equipment. Solutions to this problem are also offered in this paper.

In photovoltaic, fuel cells and storage batteries, the low output DC voltage should be boosted. Therefore, a step-up converter is necessary to boost the low DC voltage for the DC link voltage of the inverter. The main contribution of this chapter is to electrical energy conversion in renewable energy systems based on multilevel inverters. Different configuration of renewable energy systems based on power converters will be discussed in detail. Finally, a new single inductor Multi-Output Boost (MOB) converter is proposed, which is compatible with the diode-clamped configuration. Steady state and dynamic analyses have been carried out in order to show the validity of the proposed topology. Then the joint circuit of the proposed DC-DC converter with a three-level diode-clamped converter is presented in order to have a series regulated voltage at the DC link voltage of the diode-clamped inverter. MOB converter can boost the low input DC voltage of the renewable energy sources and at the same time adjust the voltage across each capacitor to the desired voltage levels, thereby solving the main problem associated with capacitor voltage imbalance in this type of multilevel converter.

Due to the increasing presence of renewable inertia-less energy sources, power electronics interfaces are required to exploit their flexibility in order to support the overall grid quality of service. One way to achieve this, is that power converters are capable of actively track active and reactive power-setpoints, that are computed by suitable centralized or decentralized control schemes. In this paper, we propose a novel algorithm which enables the control of a boost converter to achieve arbitrary active-power reference tracking for photovoltaic plants, not operating in maximum power point tracking (MPPT) mode.