472 research outputs found

    Design challenges in the use of silicon carbide JFETs in matrix converter applications

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    This paper investigates some of the challenges en¬countered during the implementation of a Silicon Carbide JFET matrix converter which has been designed to meet a specific power density of 20kW/litre with forced air cooling. After a brief introduction to the main features of the hardware implementation of the power converter, an insight into the control strategy and controller platform adopted is given with a particular attention to the issues relating to the high switching frequencies on the controller requirements and the performance implications of the gate drive circuitry. An analysis of the results which show the effects of gate driver and controller induced commutation time limitations on the output waveform quality is presented. Wide bandgap semiconductor devices offer the power electronic engineer new opportunities for high speed, high efficiency designs but these devices cannot be used as a simple like for like replacements and as such the whole converter system needs to be looked at

    Development of an image converter of radical design

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    A long term investigation of thin film sensors, monolithic photo-field effect transistors, and epitaxially diffused phototransistors and photodiodes to meet requirements to produce acceptable all solid state, electronically scanned imaging system, led to the production of an advanced engineering model camera which employs a 200,000 element phototransistor array (organized in a matrix of 400 rows by 500 columns) to secure resolution comparable to commercial television. The full investigation is described for the period July 1962 through July 1972, and covers the following broad topics in detail: (1) sensor monoliths; (2) fabrication technology; (3) functional theory; (4) system methodology; and (5) deployment profile. A summary of the work and conclusions are given, along with extensive schematic diagrams of the final solid state imaging system product

    Impact of silicon carbide device technologies on matrix converter design and performance

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    The development of high power density power converters has become an important topic in power electronics because of increasing demand in transportation applications including marine, aviation and vehicle system. The possibility for greater power densities due to absence of a DC link is made matrix converter topologies more attractive for these applications. Additionally, with the emerging SiC device technology, the operating switching frequency and temperature of the converter can be potentially increased. The extended switching frequency and temperature range provide opportunities to further improve the power density of the power converters. The aim of this thesis is to understand how SiC devices are different from the conventional Si devices and the effect these differences have on the design and performance of a matrix converter. Specific gate drive circuits are designed and implemented to fully utilize the high speed switching capabilities of these emerging semiconductor devices. A method to evaluate the conduction and switching losses and performance of Si and SiC power devices in the matrix converter circuit is developed. The developed method is used to compare power losses of matrix converters designed with different Si and SiC devices for a range of operating temperatures and switching frequencies. A design procedure for matrix converter input filters is proposed to fulfil power quality standard requirements and maximize the filter power density. The impact of the switching frequency on the input filter volume has also been considered in this work. The output waveform distortion due to commutation time in high switching frequency SiC matrix converters is also investigated and a three-step current commutation strategy is used to minimize the problem. Finally the influence of parasitic inductance on the behaviour of SiC power MOSFET matrix converters is investigated to highlight the challenges of high speed power devices

    Impact of silicon carbide device technologies on matrix converter design and performance

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    The development of high power density power converters has become an important topic in power electronics because of increasing demand in transportation applications including marine, aviation and vehicle system. The possibility for greater power densities due to absence of a DC link is made matrix converter topologies more attractive for these applications. Additionally, with the emerging SiC device technology, the operating switching frequency and temperature of the converter can be potentially increased. The extended switching frequency and temperature range provide opportunities to further improve the power density of the power converters. The aim of this thesis is to understand how SiC devices are different from the conventional Si devices and the effect these differences have on the design and performance of a matrix converter. Specific gate drive circuits are designed and implemented to fully utilize the high speed switching capabilities of these emerging semiconductor devices. A method to evaluate the conduction and switching losses and performance of Si and SiC power devices in the matrix converter circuit is developed. The developed method is used to compare power losses of matrix converters designed with different Si and SiC devices for a range of operating temperatures and switching frequencies. A design procedure for matrix converter input filters is proposed to fulfil power quality standard requirements and maximize the filter power density. The impact of the switching frequency on the input filter volume has also been considered in this work. The output waveform distortion due to commutation time in high switching frequency SiC matrix converters is also investigated and a three-step current commutation strategy is used to minimize the problem. Finally the influence of parasitic inductance on the behaviour of SiC power MOSFET matrix converters is investigated to highlight the challenges of high speed power devices

    Design, implementation, and stability analysis of a space vector modulated direct matrix converter for power flow control in a more reliable and sustainable microgrid

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    © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This paper presents a detailed study on technical points of design, control, stability analysis, and hardware development of a direct matrix converter with power flow control for microgrid applications. The converter is used as an interface between a microgrid AC bus and a variable-frequency load, e.g., an induction machine. The main steps of the converter design include the design of input filter, stabilization, commutation, and protection techniques. Practical guidelines are provided for the direct conversion and transmission of modulation and control procedures to the logic processing devices. Through a detailed study of stabilization technique using damping resistors, the stability region of the converter is determined by using the linearized state-space equations. A prototype direct matrix converter has been developed by the proposed design procedures, and experimentally tested for a variable frequency load

    Real-Time Machine Learning Based Open Switch Fault Detection and Isolation for Multilevel Multiphase Drives

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    Due to the rapid proliferation interest of the multiphase machines and their combination with multilevel inverters technology, the demand for high reliability and resilient in the multiphase multilevel drives is increased. High reliability can be achieved by deploying systematic preventive real-time monitoring, robust control, and efficient fault diagnosis strategies. Fault diagnosis, as an indispensable methodology to preserve the seamless post-fault operation, is carried out in consecutive steps; monitoring the observable signals to generate the residuals, evaluating the observations to make a binary decision if any abnormality has occurred, and identifying the characteristics of the abnormalities to locate and isolate the failed components. It is followed by applying an appropriate reconfiguration strategy to ensure that the system can tolerate the failure. The primary focus of presented dissertation was to address employing computational and machine learning techniques to construct a proficient fault diagnosis scheme in multilevel multiphase drives. First, the data-driven nonlinear model identification/prediction methods are used to form a hybrid fault detection framework, which combines module-level and system-level methods in power converters, to enhance the performance and obtain a rapid real-time detection. Applying suggested nonlinear model predictors along with different systems (conventional two-level inverter and three-level neutral point clamped inverter) result in reducing the detection time to 1% of stator current fundamental period without deploying component-level monitoring equipment. Further, two methods using semi-supervised learning and analytical data mining concepts are presented to isolate the failed component. The semi-supervised fuzzy algorithm is engaged in building the clustering model because the deficient labeled datasets (prior knowledge of the system) leads to degraded performance in supervised clustering. Also, an analytical data mining procedure is presented based on data interpretability that yields two criteria to isolate the failure. A key part of this work also dealt with the discrimination between the post-fault characteristics, which are supposed to carry the data reflecting the fault influence, and the output responses, which are compensated by controllers under closed-loop control strategy. The performance of all designed schemes is evaluated through experiments

    Improved space vector modulation with reduced switching vectors for multi-phase matrix converter

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    Multi-phase converter inherits numerous advantages, namely superior fault tolerance, lower per-leg power rating and higher degree of freedom in control. With these advantages, this thesis proposes an improved space vector modulation (SVM) technique to enhance the ac-to-ac power conversion capability of the multi-phase matrix converter. The work is set to achieve two objectives. First is to improve the SVM of a three-to-seven phase single end matrix converter by reducing number of space vector combinations. Second is to use the active vector of the SVM to eliminate the common-mode voltage due to the heterogeneous switching combination of a dual three-to-five phase matrix converter. In the first part, the proposed technique utilizes only 129 out of 2,187 possible active space vectors. With the reduction, the SVM switching sequence is greatly simplified and the execution time is shortened. Despite this, no significant degradation in the output and the input waveform quality is observed from the MATLAB/Simulink simulation and the hardware prototype. The results show that the output voltage can reach up to 76.93% of the input voltage, which is the maximum physical limit of a three-to-seven phase matrix converter. In addition, the total harmonics distortion (THD) for the output voltage is measured to be below 5% over the operating frequency range of 0.1 Hz to 300 Hz. For the second part, the common-mode voltage elimination is based on the cancellation of the resultant vectors (that causes the common-mode to be formed), using a specially derived active vectors of the dual matrix converter. The elimination strategy is coupled with the ability to control the input power factor to unity. The proposed concept is verified by the MATLAB/Simulink simulation and is validated using a 5 kW three-to-five phase matrix converter prototype. The SVM switching algorithm itself is implemented on a dSPACE-1006 digital signal processor platform. The results prove that the common-mode voltage is successfully eliminated from the five-phase induction motor winding. Furthermore, the output phase voltage is boosted up to 150% of the input voltage in linear modulation range

    Industrial and Technological Applications of Power Electronics Systems

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    The Special Issue "Industrial and Technological Applications of Power Electronics Systems" focuses on: - new strategies of control for electric machines, including sensorless control and fault diagnosis; - existing and emerging industrial applications of GaN and SiC-based converters; - modern methods for electromagnetic compatibility. The book covers topics such as control systems, fault diagnosis, converters, inverters, and electromagnetic interference in power electronics systems. The Special Issue includes 19 scientific papers by industry experts and worldwide professors in the area of electrical engineering
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