1,720,997 research outputs found
A new approach for power losses evaluation of IGBT/diode module
Full text linkElectric power systems are facing tremendous changes and power electronic devices are playing an increasingly crucial role in this transformation. In this contest, the study of power electronic devices behavior becomes of the utmost importance, and in particular, evaluation of their losses to understand their performance. Several methods can be found in literature to evaluate power or energy losses, but each of them is associated with shortcomings (such as missing an important factor or having narrow current or voltage range) that in practice become a strong limit to implement them or in a simulation process. To overcome this problem, this paper evaluates existing methods and proposes new loss calculation methods for power electronics losses that can be used within simulation tools at any converter configuration and application range, splitting power electronic losses into switching and conduction losses. The proposed new approach formulates each loss calculation procedure in a systematic way. The presented methods are implemented in Matlab Simulink and simulation results are compared with data obtained from the Semikron SemiSel v4 online tool, which is used as a benchmark. The outcomes reveal that, with this new approach, the proposed methods can cover wider working operation range compared to the existing methods having better accuracy
Energy Efficiency in Magnetic Clamping Applications
No full textMagnetic clamping systems are a good substitute for mechanical ones in the industrial field to clamp workpieces on machine tools or to lift and handle ferrous material. Concerning big dimensions lifting applications, electromagnetic and electro-permanent are the most suitable magnetic clamping systems. A considerable energy efficiency difference is present between these two systems, but often it is not simple to evaluate. So a prototype has been developed to put in evidence the main differences: a hybrid control system for electromagnetic or electro-permanent systems has been created. A single control unit exploited by both systems only by changing the type of lifting magnet has been the idea behind the realization of such a hybrid control system, here described to evaluate the energy differences between these two magnetic clamping systems
Dynamic Voltage Conditioner, a New Concept for Smart Low-Voltage Distribution System
Full text linkPower Quality (PQ) improvement in distribution level is an increasing concern in modern electrical power systems. One of the main problems in LV networks is related to load voltage stabilization close to the nominal value. Usually this problem is solved by Smart Distribution Transformers, Hybrid Transformers and Solid-state Transformers, but also Dynamic Voltage Conditioner (DVC) can be an innovative and a cost effective solution. The paper introduces a new control method of a single-phase DVC system able to compensate these long duration voltage drifts. For these events, it is mandatory to avoid active power exchanges so, the controller is designed to work with non-active power only. Operation limits for quadrature voltage injection control is formulated and reference voltage update procedure is proposed to guarantee its continuous operating. DVC performance for main voltage and load variation is examined. Proposed solution is validated with simulation study and experimental laboratory tests. Some simulation and experimental results are illustrated to show the prototype device's performance
Reduction Power Point Tracking for Standalone PV Systems: Preliminary Studies
No full textThis work proposes a Novel Reduction Power Point Tracking (RPPT) technique for Standalone PV systems. This technique enables PV System to dynamically adjust the PV power extracted to match the varying load demand in Standalone PV Systems. To understand the feasibility of the RPPT technique, preliminary studies are performed to understand operating points on both sides of the Maximum Power Point (MPP) on the PV characteristics curve for implementation. Using the Perturb and Observe (PO) embedded RPPT algorithm, simulation studies are performed under varying irradiance and varying load conditions to verify the tracking performance on both sides of MPP on the PV characteristics. This work helps in proliferation of the PV installations in developing nations and off grid systems, enhancing their utilization factor and also reduction in investment costs for supplementary energy sources accompanying the PV System
Wind speed component analysis on the Dynamic Thermal Line Rating
No full textIn order to optimize the investment costs in electrical infrastructures, it is increasingly important to exploit power system components as close as possible to their thermal limits. The temperature of overhead transmission lines is one of the major aspects to take into account to ensure safe and reliable grid operation: its estimation allows Transmission System Operators to efficiently manage the grid and to maintain a constant power supply service, eventually implementing proper corrective actions. In the present paper, two physical approaches for overhead lines temperature estimation, namely IEEE and CIGRE models, are tested and compared on four datasets coming from different Italian overhead lines. In detail, they are involved in the five-minutes-ahead conductor temperature estimation. A successful application of the proposed models requires a proper assessment of the line angle, a crucial input parameter to get reliable results. However, it is often unavailable and difficult to be correctly estimated. A specific procedure, aimed at computing the optimal line angle that maximize the accuracy of line temperature estimation, is proposed in this work
AC "back to back" switching device in industrial application
Full text linkIn industrial applications, among several varieties of semiconductor devices available, a silicon-controlled rectifier (SCR) is often used in managing and protecting various systems with different applications. Hence, it is of the utmost importance to design a control system which can operate over a range of electrical loads without any modifications in its hardware and/or software. This paper analyzes and investigates in detail the power circuit effects on conduction delay and SCR functioning. Moreover, two different commonly used driving systems for SCR application have been introduced, discussed, and evaluated. Concerning driving systems, here, three aspects have paramount importance and are consequently taken into consideration, namely the driver system losses, the conduction delay, and in particular, some power quality indices. The conduction delay is a parameter of great importance, as being able to control and reduce it to the minimum allowed by the application can bring significant practical advantages (both in terms of application and economic terms, as better summarized in the article). Theoretical analysis has been performed, followed and verified by simulation studies and, for some cases, laboratory experimental test results are presented which provide credibility to the study
Control algorithm extension for series power electronic converter
No full textThe Low Voltage distribution network is becoming intricate due to the proliferation of distributed micro-generation from renewable sources. Due to this, the Distribution System Operators (DSOs) are faced by diverse challenges especially in managing the network voltage. To deal with it, one of the effective and economically viable solution is to use a Series Power Electronic Converter (SPEC), which continuously monitors and compensates the voltage at the point of installation in the network to a defined set-point and also responds to shallow power quality events like sags and swells. Thanks to an adopted strategy, this compensation is achieved purely based on reactive power avoiding costs related to active storage systems. Previous works shows SPEC capabilities even with various limits correlated to the load power factor, thanks to the implemented SPEC control logic which is developed to compensate voltage under passive, inductive or capacitive loads. As these strategies has a strong dependence on the type of load, the existing control logic needs to be updated for the SPEC to compensate for active loads like Photovoltaic. Hence in this work implementation of an Adaptive Energy Optimised Control (AEOC) algorithm which adjusts the voltage compensation strategy based on the active, passive, inductive or capacitive loading conditions is proposed. The designed algorithm is implemented as C function and is validated through simulations in Typhoon HIL for better practical applicability. The results show the enhancement of SPEC capabilities to operate under diverse loads
DC microgrid for power sharing model. Control techniques analysis
No full textIn recent years, because of the energy crisis and fossil fuels depletion, Renewable Energy Sources (RES) are more and more deployed to meet the energy demand and their strategic importance is rising more than ever. Most of them are natively sources in DC, moreover many loads, such as electric vehicles and most electronic devices, are natively loads in DC too. The latest European directives introduced the concepts of Renewable Energy Communities (REC) and collective self-consumption. These communities are increasingly attractive and, considering that the collective self-consumption (as power sharing) can be easily applied when the community is based on a DC microgrid, this network topology is more and more developed and studied. In this paper, the authors want to investigate the possible control approaches suitable for the management of a DC microgrid designed to realize collective self-consumption through a power sharing model. A possible architecture for the DC microgrid is presented, highlighting the main elements which can be actively included in control algorithms and the main tasks to be pursued. Different control approaches are analysed and compared, highlighting the main benefits and limits of specific applications and configurations
Integration of fault current limiting function into a single-phase series compensator
No full textSingle-phase Series Compensators are very attractive electronic device for Distribution System Operator (DSO) in order to increase power quality level and load management in LV networks with reduced investment cost. One of the main important problem in LV network is due to voltage drop. The main approach to mitigate voltage drop, is employing custom power system devices as uninterruptible power supply or adapt solid-state transfer switch. Nowadays, also Dynamic Voltage Conditioners (DVC) or Dynamic Voltage Restorers (DVR) are effective apparatus and economically justified solution to compensate voltage disturbances. In contrary to the previous solutions, these devices can be efficiently used not only to solve the problem of voltage disturbance for the loads, but also to mitigate the disturbances of the upstream LV network due to a fault in the downstream by limiting the downstream fault current. Generally, there are two main strategies in order to limit downstream fault current in DVC or DVR devices: The conventional passive strategy and the innovative active one. This paper analyzes the operation principle of active solutions integrating a Fault Current Limiting (FCL) function into a DVC device, by simulation results in MATLAB environment and comparing their performance
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