Showing 3 results for Torkaman
H. Torkaman, T. Hemmati,
Volume 14, Issue 1 (March 2018)
Abstract
This paper introduces a novel two transistors forward topology employing a z-source to achieve ZVZCS and power transformer resetting for various applications. Comparing with the forward converter, this topology has the advantage of displaying ZCS condition with an added Z-Source and no additional switches when the switches turn on, and that ZVS condition happens when the switches turn off. Duty cycle of the topology can exceed 50 percent. As a result, these converters are suitable for applications with high efficiency. In this paper, structure and properties of the topology will be discussed in details. Then the design principles will be presented. Finally, the benefits aforementioned will be approved in practice through a simple forward converter.
Ali Zarghani, Pedram Dehgoshaei, Hossein Torkaman, Aghil Ghaheri,
Volume 20, Issue 1 (March 2024)
Abstract
Losses in electric machines produce heat and cause an efficiency drop. As a consequence of heat production, temperature rise will occur which imposes severe problems. Due to the dependence of electrical and mechanical performance on temperature, conducting thermal analysis for a special electric machine that has a compact configuration with poor heat dissipation capability is crucial. This paper aims to carry out the thermal analysis of an axial-field flux-switching permanent magnet (AFFSPM) machine for electric vehicle application. To fulfill this purpose, three-dimensional (3D) finite element analysis is performed to accurately derive electromagnetic losses in active components. Meanwhile, copper losses are calculated by analytic correlation in maximum allowable temperature. To improve thermal performance, cooling blades are inserted on the frame of AFFSPM, and 3D computational fluid dynamics (CFD) is developed to investigate thermal analysis. The effect of different housing materials, the external heat transfer coefficient, and various operating points on the components' temperature has been reported. Finally, 3-D FEA is used to conduct heat flow path and heat generation density.
Milad Babalou, Hossein Torkaman, Edris Pouresmaeil, Nazanin Pourmoradi,
Volume 20, Issue 2 (June 2024)
Abstract
In this paper, a dual-active bridge converter based on the utilization of two transformers is presented. The principles of operation, switching strategy, and transmission power characteristics of the proposed converter under normal operation are discussed, comprehensively. Moreover, the RMS current of two transformers with different values of inductances of the inductors that are in series with the transformers; is discussed. The operation of the proposed dual active bridge (DAB) converter under the open-circuit failure of transformers is studied. In addition, the loss distribution of the proposed converter in different powers is investigated. The proposed dual-transformer-based dual-active bridge converter is compared with the presented converters. Finally, the proposed converter with a low-voltage side (VL= 300 V), the switching frequency of power MOSFETs (fs= 50 kHz), and an accurate model of the electric battery at a high-voltage side (VH= 450 V) are simulated to verify the way of charging and discharging the electrical battery with the proposed converter under normal and open-circuit fault of transformers.
