Browsing by Author "Rouzbehi, Kumars"
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- An Asymmetrical Step-Up Multilevel Inverter Based on Switched-Capacitor Network
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-06-02) Taghvaie, Amir; Alijani, Ahmad; Adabi, M. Ebrahim; Rezanejad, Mohammad; Adabi, Jafar; Rouzbehi, Kumars; Pouresmaeil, EdrisThis paper presents a transformerless step-up multilevel inverter based on a switched-capacitor structure. One of the main contributions of the proposed topology is replacing the separated DC voltage source with capacitors which are charged at predetermined time intervals. Therefore, a high-level staircase voltage waveform can be achieved by discharging some of these capacitors on the load. The other contribution of the proposed structure is to eliminate the magnetic elements which traditionally boost the input DC voltage. In addition, asymmetrical or unequal amounts of capacitor voltages create more voltage levels, which enable voltage level increments without increasing the number of semiconductor devices. This paper introduces a self-balanced boost Switched-Capacitors Multilevel Inverter (SCMLI) which is able to create a nearly sinusoidal voltage waveform with a maximum voltage of up to 45 times that of the input voltage DC source. Higher level output voltage levels are also achievable by extending the circuit topology. After determination of the switching angles and selecting the proper switching states for each level, an offline NLC method is used for modulation, which eases the control implementation. Analysis, simulation and experiments are carried out for a 91-level inverter (45 levels for positive and negative voltages and one for zero voltage) are presented. - A Compound Current Limiter and Circuit Breaker
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-05-01) Heidary, Amir; Radmanesh, Hamid; Bakhshi, Ali; Rouzbehi, Kumars; Pouresmaeil, EdrisThe protection of sensitive loads against voltage drop is a concern for the power system. A fast fault current limiter and circuit breaker can be a solution for rapid voltage recovery of sensitive loads. This paper proposes a compound type of current limiter and circuit breaker (CLCB) which can limit fault current and fast break to adjust voltage sags at the protected buses. In addition, it can act as a circuit breaker to open the faulty line. The proposed CLCB is based on a series L-C resonance, which contains a resonant transformer and a series capacitor bank. Moreover, the CLCB includes two anti-parallel power electronic switches (a diode and an IGBT) connected in series with bus couplers. In order to perform an analysis of CLCB performance, the proposed structure was simulated using MATLAB. In addition, an experimental prototype was built, tested, and the experimental results were reported. Comparisons show that experimental results were in fair agreement with the simulation results and confirm CLCB’s ability to act as a fault current limiter and a circuit breaker. - Control of MMC-Based STATCOM as an Effective Interface between Energy Sources and the Power Grid
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019) Shahnazian, Fatemeh; Adabi, M. Ebrahim; Adabi, Jafar; Pouresmaeil, Edris; Rouzbehi, Kumars; Rodrigues, Eduardo M.G.; Catalão, João P.S.This paper presents a dynamic model of modular multilevel converters (MMCs), which are considered as an effective interface between energy sources and the power grid. By improving the converter performance, appropriate reactive power compensation is guaranteed. Modulation indices are calculated based on detailed harmonic evaluations of both dynamic and steady-state operation modes, which is considered as the main contribution of this paper in comparison with other methods. As another novelty of this paper, circulating current control is accomplished by embedding an additional second harmonic component in the modulation process. The proposed control method leads to an effective reduction in capacitor voltage fluctuation and losses. Finally, converter’s maximum stable operation range is modified, which provides efficiency enhancements and also stability assurance. The proficiency and functionality of the proposed controller are demonstrated through detailed theoretical analysis and simulations with MATLAB/Simulink. - A Data-Driven Based Voltage Control Strategy for DC-DC Converters: Application to DC Microgrid
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-05-01) Rouzbehi, Kumars; Miranian, Arash; Escaño, Juan Manuel; Rakhshani, Elyas; Shariati, Negin; Pouresmaeil, EdrisThis paper develops a data-driven strategy for identification and voltage control for DC-DC power converters. The proposed strategy does not require a pre-defined standard model of the power converters and only relies on power converter measurement data, including sampled output voltage and the duty ratio to identify a valid dynamic model for them over their operating regime. To derive the power converter model from the measurements, a local model network (LMN) is used, which is able to describe converter dynamics through some locally active linear sub-models, individually responsible for representing a particular operating regime of the power converters. Later, a local linear controller is established considering the identified LMN to generate the control signal (i.e., duty ratio) for the power converters. Simulation results for a stand-alone boost converter as well as a bidirectional converter in a test DC microgrid demonstrate merit and satisfactory performance of the proposed data-driven identification and control strategy. Moreover, comparisons to a conventional proportional-integral (PI) controllers demonstrate the merits of the proposed approach. - Employing Virtual Synchronous Generator with a New Control Technique for Grid Frequency Stabilization
A4 Artikkeli konferenssijulkaisussa(2020) Saeedian, Meysam; Eskandari, Bahman; Rouzbehi, Kumars; Taheri, Shamsodin; Pouresmaeil, EdrisThis paper aims to develop a control technique for grid-interfaced voltage source converters in distributed power generation systems. The proposed method is composed of two control loops, i.e., inner and outer controllers. The former one is based on a fast current control technique, with the capability of handling active and reactive power. The inertial characteristic of conventional synchronous generators is mimicked by means of the outer control loop, with the aim of providing required inertia for the main grid. This developed control strategy results in mitigation of frequency nadir and rate of change of frequency level in the system frequency response, and thereby, frequency stability during disturbances. Herein, the dynamics of the suggested control scheme is first presented in the dq rotating frame for the design of current control loops. Virtual inertia emulation using the frequency-power response based topology is then discussed in detail. Finally, a 200 kVA virtual synchronous generator is simulated in MATLAB to support theoretical analyses and demonstrate the appropriate performance of the suggested technique in control of interfaced voltage source converters between distributed energy sources and power grids. - Integration of Large Scale PV-Based Generation into Power Systems: A Survey
A2 Katsausartikkeli tieteellisessä aikakauslehdessä(2019) Rakhshani, Elyas; Rouzbehi, Kumars; Sánchez, Adolfo J.; Cabrera Tobar, Ana; Pouresmaeil, EdrisThis paper reports a general overview of current research on analysis and control of the power grid with grid scale PV-based power generations as well as of various consequences of grid scale integration of PV generation units into the power systems. Moreover, the history of PV renewable growth, deregulation of power system and issues related to grid-connected PV systems considering its contribution to various responsibilities like frequency control, virtual inertia capabilities and voltage regulation are discussed. Moreover, various outcomes of the high-penetrated grid with PV power plants such as power quality, active and reactive power control, protection, balancing and reliability under various loading conditions are reviewed and discussed. - A Multi-Inductor H Bridge Fault Current Limiter
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2019-07-16) Heidary, Amir; Radmanesh, Hamid; Moghim, Ali; Ghorbanyan, Kamran; Rouzbehi, Kumars; Rodrigues, Eduardo M.G.; Pouresmaeil, EdrisCurrent power systems will suffer from increasing pressure as a result of an upsurge in demand and will experience an ever-growing penetration of distributed power generation, which are factors that will contribute to a higher of incidence fault current levels. Fault current limiters (FCLs) are key power electronic devices. They are able to limit the prospective fault current without completely disconnecting in cases in which a fault occurs, for instance, in a power transmission grid. This paper proposes a new type of FCL capable of fault current limiting in two steps. In this way, the FCLs’ power electronic switches experience significantly less stress and their overall performance will significantly increase. The proposed device is essentially a controllable H bridge type fault current limiter (HBFCL) that is comprised of two variable inductances, which operate to reduce current of main switch in the first stage of current limiting. In the next step, the main switch can limit the fault current while it becomes open. Simulation studies are carried out using MATLAB and its prototype setup is built and tested. The comparison of experimental and simulation results indicates that the proposed HBFCL is a promising solution to address protection issues.