1,721,104 research outputs found
Test cycle simulation of an electric car with regenerative braking
No full textIn the near future electric cars will be ubiquitous thanks to their wider functionalities and to their much lower tailpipe emissions to the environment. However, at present, there are still problems concerning the storage of energy for long range operation. It is therefore important to employ strategies to preserve the State of Charge (SoC) of batteries as much as possible. The first important strategy is related to the driving style in order to minimize frequent acceleration-braking sequences. Once this condition has been met, the next strategy could be the partial recharge of battery during braking, recovering the kinetic energy of the car mass. This paper presents the simulation of a simple mechanical quarter-car model whose wheel is driven by a Permanent Magnet Synchronous Motor (PMSM) motor. The focus is on the electric control of the motor and on the energy recovery. The PMSM could accelerate and brake the car in all conditions, but this solution depletes the battery also in braking. There is a better strategy that use a combination of regenerative braking (battery recharge) and dissipative mechanical braking. In order to produce meaningful results, the simulations follow the class 3 time-speed data points of the Worldwide Harmonized Light vehicles Test Cycles (WLTC) developed for Pure Electric Vehicles (PEV)
A novel three-phase single-stage distributed power inverter
No full textIn this paper, a novel three-phase, dc/ac converter suitable for distributed power applications is proposed. The system consists of three dc/dc boost converters with a common point and operating as a three-phase inverter with intrinsic step-up capability. The converter obtained can invert, amplify and, where possible, regenerate bidirectional power sources such as fuel-cells, small gas turbines, and photovoltaic arrays. There are two main advantages to the system: the use of only six insulated gate bipolar transistors and small passive elements, and the fact that it does not need reverse voltage blocking capability. Simulation and experimental results show the effectiveness of the proposed system during both steady-state and dynamic operations
Monitoring, Diagnosis, Prognosis, and Techniques for Increasing the Lifetime/Reliability of Photovoltaic Systems
No full textThe articles in this special section focus on photovoltaic power systems (PVS). The market for photovoltaic power systems has increased exponentially, but the government subsidies have been reduced dramatically in recent years. The return of the investment mainly relies on selling the energy produced during the PV plant lifetime. Thus, the PV system must be designed and controlled properly in order to ensure its lifetime and reliability but also new features are required: 1) real-time monitoring of the energy production; 2) on-site diagnostic functions; and 3) estimation of the residual life. The degradation of electronic components and PV cells can be accelerated by various unpredictable and unavoidable phenomena
Neural Network Model Predictive Control for CHB Converters with FPGA Implementation
Full text linkFinite control set model-predictive control appears an interesting and effective control technique for cascaded H-bridge converters but, because of its computational complexity, becomes impractical when the number of levels of the converter increases. This article proposes a neural-network-based approach capable of overcoming the computational burden of conventional predictive control algorithms. The proposed control is, then, applied to a cascaded H-bridge static synchronous compensator using a field-programmable gate array and tested via hardware in the loop. Results and analysis demonstrate that the optimal control of multilevel converters with many levels can be obtained with low computational effort
Special Issue on More Electric Aircraft
No full textElectrification is a remarkable trend in the aviation industry. Electric machines and power electronics systems have been increasingly embedded in aerospace applications. In this field, the abovementioned systems are mainly used for flight control, engine starting/generating, propulsion, environmental control, braking, and fuel and hydraulic pumps
Mathematical proof of a harmonic elimination procedure for multilevel inverters
No full textIn this paper, a single phase cascaded H-bridge inverter with s variable dc sources (s≥2), l=2s+1 levels has been considered. A mathematical proof is presented to demonstrate that, under a particular choice of the switching angles, which number corresponds to the number of dc sources i.e. s, and of the dc voltages, all harmonics are eliminated from the output voltage waveform, except those of order n=4p⋅s±1, p=1,2,.... With this method, the dc voltage sources vary linearly according to the modulation index m, while the switching angles do not depend on m. The resulting output voltage has low total harmonic distortion, that remains independent on m. Compared to a conventional selective harmonic elimination procedure and to a pulse amplitude method, the proposed procedure reduces distortion in a wide range of modulation index
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