Mohsen Atash Ab-Parvar; Hamed Hekmati; Alireza Siadatan; Mehdi Bigdeli; Arsalan Hekmati; Mehdi Bagheri
Abstract
Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects ...
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Wind power as a renewable energy has the potential to become a clean energy source in almost all countries of the world but, there are lots of technical challenges that need to be addressed in advance. Wind speed variation (WSV) is one of the most important issues. Separate from its mechanical effects on wind turbines (WTs), it causes electrical power variations on WT as well. Doubly Fed Induction Generators (DFIGs) and Maximum Power Point Tracking (MPPT) system have been helpful so far but some problems such as inertia still needed to be solved. Inertia in the WTs causes a delay on MPPT. This paper proposes a novel method to increase WTs output power in which a DFIG equipped with an energy storage system such as Ultra-capacitor helps MPPT system to track the wind variations rapidly by absorption or injection energy during the wind changes. The ultra-capacitor and control system are modeled and simulated in Matlab/Simulink® environment. The simulation results proofs that the proposed system can improve electrical power and increase electrical energy during WSVs. The simulation model will lead to more penetration of wind power and also enables engineers to optimize the system.
Arsalan Hekmati; Iman Sadeghi Mahalli; Mohammad Siamaki
Abstract
In the PMSM, by creating a sinusoidal distribution for conductors at the stator surface, the airgap’s flux density is closer to the sinus form [1]. By replacing the field’s winding with a permanent magnet, the brushes, slip-rings, and copper losses could be removed from synchronous motor. ...
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In the PMSM, by creating a sinusoidal distribution for conductors at the stator surface, the airgap’s flux density is closer to the sinus form [1]. By replacing the field’s winding with a permanent magnet, the brushes, slip-rings, and copper losses could be removed from synchronous motor. The permanent magnet generates motors with permanent excitation. Fig. 1, shows two different ways in which permanent magnets are put into rotor .The following figure shows the ratio of magnetic torque to reluctance torque in synchronous machines. Regarding the mechanism of torque producing, synchronous machines are divided into three distinct groups. The surface-PMSM (SPMSM), in which arc-shaped permanent magnets are embedded on the surface of cylindrical rotor .Such machine is a complete PMSM which produces only magnetic torque. Synchronous reluctance machine (synRM) is a pure reluctance machine shown in Fig. 2. f. The inset SPMSM belongs to SPMSM category in terms of magnet arrangement, however it is a combined reluctance-magnetic motor because of its magnetic saliency. Interior PMSM (IPMSM) in which permanent magnets are buried inside the rotor (Fig. 2. c, d, and e) has magnetic saliency, so it is a hybrid reluctance-magnetic motor which can be considered as a PMSM motor regarding its reluctance torque (region II) or a synRM motor regarding its magnetic torque.
Arsalan Hekmati; iman sadeghi
Abstract
Synchronous speeds in all types of alternating current machines depend on the frequency of the power grid, and performance at higher speeds at steady conditions requires higher frequency feeds. The development of speed control drive technology in recent decades has prompted renewed attention to high-speed ...
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Synchronous speeds in all types of alternating current machines depend on the frequency of the power grid, and performance at higher speeds at steady conditions requires higher frequency feeds. The development of speed control drive technology in recent decades has prompted renewed attention to high-speed engines. Important advantages of using high speed electric motors include higher density (and smaller dimensions) and greater torque generation capability. Also, the use of these motors enables the removal of the gearbox and lubrication system, which reduces maintenance costs. Nowadays, surface-mounted PMSMs are increasingly used for high-speed applications, because of the merits of simple structure and high-strength of the rotor. This paper first discusses the fundamental differences in the configurations of ordinary and high-speed permanent magnet motors, considering their specific characteristics. The specimens and their properties, have been discussed. Finally, the modern applications of high-speed permanent magnet motors have been introduced. also, the main manufacturers of high speed synchronous motors have been presented.
