Flywheel axial flux permanent magnet motor alternator system design and 3D magnetic analysis for electromagnetic coil launcher

The limited energy resources available in the world and in our country has caused the need to store energy. Different methods are used for this. Flywheel energy storage systems (FESS) are one of them. Flywheels are units that store energy by turning around an axis. In general, the flywheels collect the energy on the acceleration, and during the deceleration it transmits this energy to the necessary places. They have been used as energy storage units from past to present in places where rotation movement should not be interrupted. Axial Flux Permanent Magnet (AFPM) alternators are commonly used alternator type. These machines have some unique features and advantages over radial flux machines. Noise and vibration levels are less than conventional machines. They are used in areas where electric machines are used due to their power density and efficiency advantages, especially where high torque is required at low speed. One of the points that should be taken into consideration and eliminated in axial flux machines is the cogging torque formed between the permanent magnets and the stator grooves. When the literature is examined, it has been seen that various techniques have been used in order to reduce and minimize the cogging torque, on the stator and rotor side. The techniques applied on the stator side are not preferred for the cost and production difficulties. Therefore, the techniques applied on the rotor side are used more frequently. In recent years, studies on electromagnetic launchers have gained speed. The principle of operation of the electromagnetic launchers is based on magnetic theory. According to this theory; By creating a strong magnetic field, it is ensured that the object to be launched is monitored by this magnetic field. Electromagnetic launchers are generally divided into two types as coils and rails. Coil launchers are based on the principle of ejecting the object between these coils with the electrical pushing force generated by the successive drive coils. Coil launchers play an important role in the launching of medium, but large objects. However, they need high energy in short periods such as 1-2sn. This energy must have a sinusoidal and high current value. Nowadays, magnetic launchers are used in military and defense areas, aircraft and missile launch systems, launching torpedoes in submarines, high-range shots of bullets and many other areas. In this study, flywheel axial flux permanent magnet motor-alternator set was designed for electromagnetic coil launchers and the magnetic analysis of this design was carried out by the 3D Maxwell program of ANSYS. The machine was first designed as 2P = 2 poles and then 2P = 12 poles. In both cases, magnetic analyzes were performed considering the changing parameters. Thus, it is aimed to reach the most suitable machine structure. In line with the results of magnetic analysis, the production of energy storage system with flywheel will be carried out in subsequent studies. For the 2-pole AFPM machine, the foot width Ag, the foot height Ah, the width Sg, the yoke height Bh, the magnet angle Md, the air gap Airg, the magnet height Mh and the non-embedded part height Mgh values of the magnet are taken as variable in the program. As a result of the analyzes, the values obtained for Ag, Ah, Md, Mh and Mgh were 2.5-3mm, 10-12mm, 50, 7-8mm and 0mm respectively. Magnetic analysis for 12-pole AFPM machine structure included Maxwell 3d program with foot width Ag, foot height Ah, yoke height Bh, magnet angle Md, air gap Airg and rotor angular rotation degree AlphaR values as variable. When the results for 12-pole EASM machine structure were examined, Ag, Ah and Md were determined as the most suitable values of 5-6mm, 12mm and 30 degree, respectively.