Design of 2 state alternator for flywheel energy storage systems

Today, the recovery of energy in systems has become an important subject of study. The most studied areas for energy recovery are super capacitors and flywheels. Flywheels are the elements that store energy in kinetics. Flywheels are characterized by high cycle life and high power density. In this study, multi-pole and multi-wind alternator structure is designed for flywheel energy storage systems. The designed alternator structure is a compact design, high power density and high efficiency axial flux permanent magnet (EASM) alternator. Thus, it is aimed to obtain maximum energy with EASM alternator structure which is designed within as a compact structure. When the energy storage systems (VEDS) with flywheel are examined, it is seen that the energy is very suitable for short periods of storage. VEDS systems are divided into two groups as high speed and low speed. The low speed range is up to 10000 rpm. When the flywheel speed rises above 10000 rpm, it is called high speed. When the studies on the literature on VEDS are examined; It is seen that electric vehicles are used in the recovery of energy fluctuations in renewable energy systems, in the recovery of brake energy, in fluctuations in energy transmission lines, in space applications and in providing energy to coil magnetic launchers. In this study, kinetic energy storage of the flywheel has been provided by mechanical bearings at low speed (460 rpm). For the flywheel, a disc-like structure with a radius of 15cm is used. The energy that the flywheel can store at a speed of 460 rpm was calculated as 493 joule. In the designed EASM alternator structure, double identical winding is used. The purpose of this winding structure is to take energy gradually in different situations. The experimental results obtained were taken from single winding, series connected state and parallel connected conditions. The designed EASM alternator structure has an open corrugated structure for ease of production. The trapezoidal winding structure was used as a full mold. The rotor has a 12-pole structure. Rectangular type neodymium magnets were used. Designed with EASM alternator A and B winding. The phase values for winding A are 24.9 and 91 volts at 125 and 459 rpm respectively. The phase values obtained for winding B are 24.8 and 90.2 volts at 126.6 and 457 rpm respectively. Considering the values, it is seen that the windings are identical for the same speeds. In the regenerative mode, the energies obtained within 0.5 s are calculated by using 6stage load. The experimental results obtained have a maximum of 332 joule for the winding A, 474 joule for the series connected state of the windings and 463 joule for the parallel state. The energy calculated for the flywheel at 460 rpm is 493 joule. In this case, the highest energy at 460 rpm was obtained from the series winding. The energy obtained from the series winding is 3.8% less than the total energy.