Showing 4 results for Rezaee
H. Heydari, M. Rezaee,
Volume 6, Issue 4 (December 2010)
Abstract
The principle object of this paper is to offer a modified design of Rogowski coil based on its frequency response. The improvement of the integrator circuit for nullifying the phase difference between the waveforms of the measured-current and the corresponding terminal voltage is a further object of this investigation.
This paper addresses an accurate, yet more efficient measuring and protecting device for low frequency applications. This requires verification for the simulations by physical descriptions and experimental results. These validate the superior performance of Rogowski coils over conventional current transformers.
Keywords: current transformer, frequency response, integrator circuit, mutual inductance, Rogowski coil, terminal resistor
B Rezaeealam,
Volume 9, Issue 4 (December 2013)
Abstract
The purpose of this paper is to introduce a new technique for row spacing measurement in a wire array using giant magnetoresistive (GMR) sensor. The self-rectifying property of the GMR-based probes leads to accurately detection of the magnetic field fluctuations caused by surface-breaking cracks in conductive materials, shape-induced magnetic anisotropy, etc. The ability to manufacture probes having small dimensions and high sensitivity (11 mV/mT) to low magnetic fields over a broad frequency range (from dc up to 1 MHz) enhances the spatial resolution of such a probe that is applicable to eddy current testing (ECT) techniques. Here, an AC uniform magnetic field is formed using a Helmholtz coil in which by scanning the probe over an array of acupuncture needles, the distances between them are detected. The results verified the possibility and the performance of the proposed row spacing measurement using GMR sensor.
F. Rezaee-Alam, B. Rezaeealam, S. M. M. Moosavi,
Volume 17, Issue 3 (September 2021)
Abstract
Poor modeling of air-gap is the main defect of conventional magnetic equivalent circuit (CMEC) model for performance analysis of electric machines. This paper presents an improved magnetic equivalent circuit (IMEC) which considers all components of air-gap permeance such as the mutual permeances between stator and rotor teeth, and the leakage permeances between adjacent stator teeth and adjacent rotor teeth in the air-gap. Since the conformal mapping (CM) method can accurately take into account the air-gap region, IMEC gets help from the CM method for calculating the air-gap permeance components. Therefore, the obtained model is a hybrid analytical model, which can accurately take into account the magnetic saturation in iron parts by using the CMEC, and the real paths of fringing flux, leakage flux, and the main flux in the air-gap by using the CM method. For a typical wound rotor induction motor, the accuracy of the results obtained by IMEC is verified by comparing them with the corresponding results determined through CMEC, improved conformal mapping (ICM), finite element method (FEM), and the experiment results.
Mehrdad Kamali, Behrooz Rezaeealam, Farhad Rezaee-Alam,
Volume 21, Issue 1 (March 2025)
Abstract
This paper investigates the operational performance of a novel Double-Rotor Hybrid Excitation Axial Flux Switching Permanent Magnet (DRHE-AFSPM) machine, combining the strengths of Flux-Switching Machines and Hybrid Excitation Synchronous Machines. The study analyzes the machine's structure and magnetic field adjustment principles, including inductance and flux linkage characteristics. A mathematical model is derived and a vector control-based drive system is established. The loading capacity of the DRHE-AFSPM motor is examined at low speeds using an id = 0 control approach based on a stage control strategy. For high-speed operation, a field-weakening control strategy is implemented, with the field-weakening moment determined based on the voltage difference. Simulations and experimental results demonstrate the DRHE-AFSPM motor's ability to fully utilize its torque with id = 0 control, highlighting its strong load capacity. Compared to speed-based field-weakening control strategies, the voltage difference-based approach offers improved inverter output voltage utilization and a broader speed regulation range. These findings suggest that the DRHE-AFSPM motor is a promising candidate for in-wheel motor applications in electric vehicles (EVs).
