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The starter generator (SG) system, which is controlled by a single driver, has started to be used in the more environmentally friendly aircraft called More Electric Aircraft, instead of two different systems as starter and generator, which are complex, heavy, and require continuous maintenance, used in traditional aircraft. In this study, a five-phase Permanent Magnet Synchronous Machine (SMSM) was used as SG due to its fault tolerance and higher energy density compared to three-phase, and low weight and volume for the same power. The SG driver controlled by five phase space vector PWM, the SG controller that manages the whole process, and the aircraft jet engine are modelled in Matlab / Simscape Tollbox. The entire aircraft SG system was controlled in three operating modes: Starter Mode, Transition Mode and Generator Mode. In the proposed system, a more advantageous 270V high voltage DC power system is used compared to the AC power system in aircraft. According to the aircraft electrical power system standard MIL-STD-704F, for the 270V high voltage DC power system, the maximum steady-state voltage fluctuation is ±6V, while the voltage fluctuation is ±1V with the proposed system. According to the same standard, the transient fall time from 350V to 270V is requested to be 0.02s and from 200V to 270V rise time to be 0.03s, while in the proposed method these times are 0.017s and 0.015s, respectively. The simulation results showed that the proposed SG system can be used as an aircraft electrical power system. [ABSTRACT FROM AUTHOR]

Purpose: More electric aircraft (MEA) is defined as the extensive usage of electric power in aircraft. The demand for electric power in new generation aircraft rises due to environmental and economic considerations. Hence, efficient and reliable starter/generators (SGs) are trending nowadays. The conventional main engine starting system and power generation system can be replaced with an individual SG. The constraints of the SG should be investigated to handle the aviation requirements. Even though the SG is basically an electric machine, it requires a multidisciplinary study consisting of electromagnetic, thermal and mechanical works to cope with aviation demands. This study aims to review conventional and new-generation aircraft SGs from the perspective of electric drive applications. Design/methodology/approach: First of all, the importance of the MEA concept has been briefly explained. Also, the historical development and the need for higher electrical power in aircraft have been indicated quantitatively. Considering aviation requirements, the candidate electrical machines for aircraft SG have been determined by the method of scoring. Those machines are compared over 14 criteria, and the most predominant of them are specified as efficiency, power density, rotor thermal tolerance, high-speed capability and machine complexity. The features of the most suitable electrical machine are pointed out with data gathered from empirical studies. Finally, the trending technologies related to efficient SG design have been explained with numeric datasets. Findings: The induction motor, switched reluctance motor and permanent magnet synchronous motor (PMSM) are selected as the candidate machines for SGs. It has been seen that the PMSM is the most preferable machine type due to its efficient operation in a wide range of constant power and speed. It is computationally proven that the using amorphous magnetic alloys in SG cores increases the machine efficiency more. Also, the benefits of high voltage direct current (HVDC) use in aircraft have been explained by a comparison of different aircraft power generation standards. It is concluded that the HVDC use in aircraft decreases total cable weight and increases aircraft operation efficiency. The thermal and mechanical tolerance of the SG is also vital. It has been stated that the liquid cooling techniques are suitable for SGs. Originality/value: The demand for electrical power in new generation aircraft is increasing. The SG can be used effectively and efficiently instead of conventional systems. To define requirements, constraints and suggestions, this study investigates the SGs from the perspective of electric drive applications. [ABSTRACT FROM AUTHOR]

The sensorless vector control of a nonsinusoidal flux-distribution permanent magnet synchronous motor (PMSM) has been performed by a trained artificial neural network (ANN) using flux data obtained from the finite element method (FEM). A more sensitive rotor position has been estimated by using the fluxes of each of the three phases of the PMSM. In the proposed approach, magnet flux of the nonsinusoidal PMSM has been calculated by FEM for every single degree. Rotor position and speed values have been estimated by training an ANN with this information. The experimental results obtained by DS1103 development kit have proved the validity of the proposed approach. [ABSTRACT FROM AUTHOR]

In this paper, new methods for reducing the torque ripple in permanent magnet synchronous motor are proposed. The methods are based on injection of appropriate current harmonics to motor by using adaptive decision fusion algorithms. Three different methods are used in determining injection of current harmonics based on q‐axis current, q‐axis voltage and reference value of the q‐axis current. In these methods, the decision values are linearly combined with weights, which are updated online according to an active fusion method, based on performing orthogonal projections onto convex sets describing these values. The validity of the proposed methods is tested with experimental studies under different operating conditions. [ABSTRACT FROM AUTHOR]

The permanent magnet synchronous motors (PMSM), which is widely used in industrial applications in recent years, require stator and rotor fields to be synchronized in order to get a smooth torque. There are so many methods for position and speed sensorless control of PMSM. But these methods change according to different types of PMSM and their working speed. V/f position and speed sensorless control of PMSM is seen attractive at the wide speed rages, because it doesn't vary according to the type of PMSM. In this paper, Fuzzy Logic Controller has been used for the stable study with the position and speed sensorless v/f control method in wide speed range. To provide the stable study, the frequency of motor voltage is altered in the rate which is estimated by Fuzzy Logic Controller by way of the pulsations of active power pulled by the motor. This method's validity is proved by using MATLAB Simulink program. [ABSTRACT FROM AUTHOR]

Back emf methods have been widely used in position and speed sensorless control of permanent magnet synchronous motors. In this method, it is conjectured that the back electromotive force induced on the stator windings by the rotor permanent magnets are sinusoidal. This conjecture causes errors in the estimation of speed and position. In this paper, the flux of stator winding was analysed by using finite element method, and the findings were used in position and speed sensorless field oriented control of permanent magnet synchronous motor. The validity of the proposed method was demonstrated by using Matlab Simulink program. [ABSTRACT FROM AUTHOR]

Copper alloys used in the automotive and white goods industry are preferred as terminals due to their high conductivity For low contact resistance and high mechanical strength of copper alloys, appropriate design selection becomes important. As a result of the coating of copper alloy, current transition level of the conductive terminal and the formation of a film that protects against corrosion on the surface are improved. The aim is to optimize the PCB terminals to be made of CuNiSiP material according to the contact forces and to produce them as gold-plated. Production is done for the CuNiSiP copper alloy supplied within the developing dimensions. With the FEA, contact forces were calculated according to different contact diameter and oral cavity parameters. The surface roughness was measured from the product contact point after the final design. The surface roughness data in the cutting zone were compared again after the prototype production, depending on the number of cycle period. During prototype production, sensitive area of terminal tip was characterized by Electron Microscopy. After the characterization, coating thickness of gold-plated regions was measured as minumum 0.8 µm by X-ray Analyses. It is experimentally proven that contact forces of PCB terminal meet the requirements. [ABSTRACT FROM AUTHOR]