Power Electronics
P. Hamedani; S. S. Fazel; M. Shahbazi
Abstract
Background and Objectives: Modeling and simulation of electric railway networks is an important issue due to their non-linear and variant nature. This problem becomes more serious with the enormous growth in public transportation tracks and the number of moving trains. Therefore, the main aim of this ...
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Background and Objectives: Modeling and simulation of electric railway networks is an important issue due to their non-linear and variant nature. This problem becomes more serious with the enormous growth in public transportation tracks and the number of moving trains. Therefore, the main aim of this paper is to present a simple and applicable simulation method for DC electric railway systems.Methods: A train movement simulator in a DC electric railway line is developed using Matlab software. A case study based on the practical parameters of Isfahan Metro Line 1 is performed. The simulator includes the train mechanical movement model and power supply system model. Regenerative braking and driving control modes with coasting control are applied in the simulation.Results: The simulation results of the power network are presented for a single train traveling in both up and down directions. Results manifest the correctness and simplicity of the suggested method which facilitates the investigation of the DC electric railway networks.Conclusion: According to the results, the train current is consistent with the electric power demand of the train. But the pantograph voltage has an opposite relationship with its electric power demand. In braking times, the excess power of the train is injected into the electrical network, and thus, overvoltage and undervoltage occur in the overhead contact line and the substation busbar. Therefore, at the maximum braking power of the train, the pantograph voltage reaches its maximum. The highest amount of fluctuation is related to the substation that is closest to the train. As the train moves away from the traction substations, the voltage fluctuations decrease and vice versa.
Hybrid EV chargers
H. Soltani Gohari; K. Abbaszadeh
Abstract
Background and Objectives: Power electronics infrastructures play an important role in charging different types of electric vehicles (EVs) especially Plug-in Hybrid EVs (PHEVs). Designing appropriate power converters is the topic of various studies.Method: In this paper, a novel bidirectional buck-boost ...
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Background and Objectives: Power electronics infrastructures play an important role in charging different types of electric vehicles (EVs) especially Plug-in Hybrid EVs (PHEVs). Designing appropriate power converters is the topic of various studies.Method: In this paper, a novel bidirectional buck-boost multifunctional integrated converter is presented which is capable of handling battery and fuel cell stack in plug-in hybrid electric vehicles. The proposed converter has the ability to work in five different operating modes (Charging/Propulsion (only battery)/ Propulsion (battery and FC)/ Regenerative braking/ V2G). The introduced multifunctional two-stage converter has the ability to work in all the above-mentioned modes in buck- boost condition, the feature that does not exist in the previous works. It is possible to control active and reactive power by using the effective dual-loop PI control method which is introduced in this paper. Working as an on-board charger and DC-DC converter (which interfaced between power sources and motor drive system) causes a decrease in the counts of the total components and an increase in system efficiency.Results: Operation principle and steady-state analysis of each stage of the proposed converter in all operating modes are provided in detail and in order to design an appropriate applicable converter, the design considerations and procedure are also explained for capacitive and inductive components. The proposed converter is simulated in MATLAB/SIMULAIN environment and results are provided. Voltage and current waveforms in all operating conditions are provided with their transient. FFT analysis of the input current (in the operating modes in which the converter absorb or deliver power from/to the grid) is also mentioned. A reduced-scale setup of the presented converter is built and tested and experimental results confirm simulation ones.Conclusion: A bidirectional buck-boost integrated converter in PHEVs applications is introduced in this paper. The design procedure of the presented converter is provided and also an effective control method to control active and reactive power during charging and V2G modes is introduced. A comparison study of the proposed converter with other similar converters introduced in recent years in terms of the number of high-frequency switches in each mode is also done. Simulation and experimental results are also provided.
