Showing 4 results for Sabahi
J. Fallah Ardashir, M. Sabahi, S. H. Hosseini, E. Babaei, G. B. Gharehpetian,
Volume 13, Issue 2 (June 2017)
Abstract
This paper proposes a new single phase transformerless Photovoltaic (PV) inverter for grid connected systems. It consists of six power switches, two diodes, one capacitor and filter at the output stage. The neutral of the grid is directly connected to the negative terminal of the source. This results in constant common mode voltage and zero leakage current. Model Predictive Controller (MPC) technique is used to modulate the converter to reduce the output current ripple and filter requirements. The main advantages of this inverter are compact size, low cost, flexible grounding configuration. Due to brevity, the operating principle and analysis of the proposed circuit are presented in brief. Simulation and experimental results of 200W prototype are shown at the end to validate the proposed topology and concept. The results obtained clearly verifies the performance of the proposed inverter and its practical application for grid connected PV systems.
F. Masoudinia, E. Babaei, M. Sabahi, H. Alipour,
Volume 16, Issue 1 (March 2020)
Abstract
In this paper, a new structure for cascade multilevel inverter is presented which consists of a series connection of several sub-multilevel units. Each sub-multilevel unit comprises of eight unidirectional switches, two bidirectional switches, and six DC voltage sources. For the proposed cascade topology, two algorithms are presented to produce all possible levels at the output voltage waveform. The required analysis of the voltage rating on the switches is provided. In order to verify the performance of the proposed inverter, the experimental results for a 15-level inverter are provided. The experimented 15-level inverter is compared with the other presented inverters in literature in terms of the number of DC voltage sources, switches, drivers, and blocked voltage by switches. The results of comparisons indicate that the experimented 15-level inverter requires lower power electronic elements. Moreover, the blocked voltage on the switches of the proposed topology is less than other topologies.
T. Ahmadzadeh, E. Babaei, M. Sabahi, T. Abedinzadeh,
Volume 16, Issue 4 (December 2020)
Abstract
The main purposes of a transformerless grid-connected photovoltaic (PV) system consist of the reduction of leakage current, extraction of maximum power point (MPP), tracking of MPP (MPPT), controlling the active and reactive powers, and having the unity power factor. To achieve the above-mentioned aims, the following actions have been performed in this paper. First of all, a brief analysis of the transformerless PV system has been done by using the conventional full-bridge (FB) topologies with two bipolar and unipolar PWM techniques. Then, an effective solution has been also introduced to significantly reduce the leakage current in the conventional H5 FB topology. Moreover, a proper control method has been proposed by using the combination of the fractional open-circuit voltage (FOCV) and the model predictive control (MPC) strategies to extract the MPP from PV panels, control the injection of the reactive power to the gird and have the unity power factor. At last, the simulation results performed in PSCAD software will be used to prove the correct performance of the proposed control method in the improved H5 FB topology.
Reza Bayat Rizi, Amir R. Forouzan, Farshad Miramirkhani, Mohamad F. Sabahi,
Volume 20, Issue 4 (Special Issue on ADLEEE - December 2024)
Abstract
Visible Light Communication, a key optical wireless technology, offers reliable, high-bandwidth, and secure communication, making it a promising soloution for a variety of applications. Despite its many advantages, optical wireless communication faces challenges in medical environments due to fluctuating signal strength caused by patient movement. Smart transmitter structures can improve system performance by adjusting system parameters to the fluctuating channel conditions. The purpose of this research is to examine how adaptive modulation performs in a medical body sensor network system that uses visible light communication. The analysis focuses on various medical situations and investigates machine learning algorithms. The study compares adaptive modulation based on supervised learning with that based on reinforcement learning. The findings indicate that both approaches greatly improve spectral efficiency, emphasizing the significance of implementing link adaptation in visible light communication-based medical body sensor networks. The use of the Q-learning algorithm in adaptive modulation enables real-time training and enables the system to adjust to the changing environment without any prior knowledge about the environment. A remarkable improvement is observed for photodetectors on the shoulder and wrist since they experience more DC gain.
