DIY Air Core Axial Flux Motor Generator
An axial flux motor (also known as an axial gap motor, or pancake motor) is a geometry of electric motor construction where the gap between the rotor and stator, and therefore the direction of magnetic flux between the two, is aligned parallel with the axis of rotation, rather than radially as with the concentric cylindrical geometry of the more common radial gap motor.
DIY Air Core Axial Flux Motor Generator
Axial motors have been commonly used for low-power applications, especially in tightly integrated electronics since the motor can be built directly upon a printed circuit board (PCB), and can use PCB traces as the stator windings. High-power, brushless axial motors are more recent, but are beginning to see usage in some electric vehicles. One of the longest produced axial motors is the brushed DC Lynch motor, where the rotor is almost entirely composed of flat copper strips with small iron cores inserted, allowing power-dense operation.
The more technical term is an axial flux generator. They too can include core irons, and you can construct them by laminating pieces of old hacksaw blades into the coils to make an iron core, to make the load curve steeper.
Abstract:Commonly, electrical energy is generated by using non-renewable energy such as natural gas, coal, and oil. As electrical energy is a basic asset for the development of a region, its utilization is increasing every year, which causes the existence of non-renewable energy to decrease every year. This issue is becoming a serious concern all over the world, which encourages every country to harness energy from renewable energy. Wind energy is a promising candidate for generating electricity today. In wind turbine generation, a three-phase generator is usually used. Along with the rapid development of power electronic devices and efforts to improve generator performances, the use of a multiphase system is considered important for harnessing energy from the wind more efficiently. In this study, a five-phase system is proposed to upgrade the output power and power density of the most qualified AFPMG in the previous study. The Taguchi optimization method is employed to obtain the lowest total harmonic distortion (THD) of the on-load voltage waveform. In addition to the Taguchi method, an Artificial Neural Network (ANN) is also employed to compare the results from the Taguchi method and the results are proven to have an excellent relationship. The data processed for Taguchi and ANN methods are strongly helped by using the finite element method from the Ansys Maxwell software. The performances of the proposed five-phase axial flux permanent magnet generator (FP-AFPMG) show good improvement, especially in THD, ripple torque, and ripple in the rectified voltage.Keywords: five-phase axial flux permanent magnet generator (FP-AFPMG); taguchi method; artificial neural network (ANN) method; generator performances
Radial-flux (RF) direct-drive (DD) machines are an alternative solution to overcome the efficiency and reliability issues of traditional solutions associated primarily with gearboxes. DD machines eliminate the gearbox and connect the generator or motor coupled directly to the load. For this solution to be effective, the motor/generator must be able to supply the required drive torque directly, and at low speed, which requires an entirely new motor/generator design.
A fundamentally different approach to direct drive is to put two sets of magnets parallel to each other, perpendicular to the axis of rotation. This axial-flux topology provides machines that are less wide and heavy than RF DD machines. As well as being more compact, AF DD machines can reach higher efficiencies than their RF DD counterparts. Axial Flux machines have much higher power density because:
Because the length of the machine is very short (140 mm for a 1600-mm outer diameter generator, for example), multiple machines (discs) can work in parallel, which is called multi-stator topology. This is usually done when the outside diameter of the generator or motor assembly must be kept limited.
The rotor has 7 poles sets distributed as "claws" around it's circumference. One set of claws is thus a "north" pole and the other set is a "south" poles. The epoxy coated N 45 neo core magnet In Hurricane Rotors deeply saturates the stator. The iron originally used in the pole claw has been replaced utilizing higher efficiency shapes and forged steel a used in Hurricane permanent magnet alternators. The magnetic flux lines within the rotor are largely constrained to flow from one pole to the other through the claw structures at each end trapezoidal claw, folding around the internal magnetic structure and passing between the claws through a zig-zag shaped circumferential air gap. There is no reverse flux flow through the rotor shaft itself. The rotor shaft is magnetically entrained and acts as yet another part of the rotor Magnetic rotor.
In short, features of a radial flux permanent magnet motor are designed on the sides. The copper windings are wrapped around slots. The flux is generated perpendicular to the axis of rotation.
For example, think of a motor for a wheel hub -- what do you want it to do, first and foremost? Produce lots of torque. Because the axial and transverse motor designs can have the rotating member located on their outer diameter, they create higher torque while reducing their motor footprint.
In a radial flux motor, magnetic flux moves from one tooth to the stator, back to the next tooth, and then to the magnets. On the other hand, an axial flux motor has a more efficient magnetic flux path: from one magnet, through the core, to another magnet.
These axial flux motors are also more efficient due to their intrinsically enhanced cooling. Because the coils can be pressed directly against the exterior motor case, they can cool much faster than in radial flux motors, which must transfer the coil heat through the stator of the motor.
What this all adds up to is a motor that can be insanely light compared to the amount of power it produces. Magnax claims their axial flux motors can reach up to 15 kW/kg peak, or 7.5 kW/kg nominal (9 hp/lb peak, or 4.5 hp/lb nominal).
This is our way of contributing to a sound environment for our children. Magnax enables industrial innovation with axial flux motor and generator technology that outperforms in efficiency, weight, reliability, and cost-effectiveness. Magnax supports the global transition to fully renewable power generation, electric transportation and ultra-efficient machines by innovating in next-generation electric motor and generator technology.
The prototype motor will be a 275 mm (10.8 inch) diameter motor weighing 22.5 kg (50 lb) and capable of between 300 to 408 kW (400-550 hp) of power. They are also developing a smaller 7 kg (15.4 lb) version of the same motor with a diameter of 185 mm (7.2 inches) and peak power output of 84 kW (113 hp). The company is envisioning the use of these motors in everything from electric motorcycles and vehicles to electric aircraft, and even in large wind turbines when used as generators.
Traditional radial flux motors, which use permanent magnets or induction motors in an electric field, are undergoing extensive development aimed at optimising their weight and cost. That can only go so far, however, so moving to a completely different machine type such as axial flux might be a good alternative.
That makes axial flux motors much more compact; the axial length of the machine is much shorter compared to radial machines, a factor that is often crucial for an application such as an inwheel motor. The slim and lightweight structure results in machines with a higher power and torque density than a comparable radial machine, without the need to resort to very high speed operation.
Axial flux motors can also be highly efficient, with efficiencies typically over 96%. That comes from the shorter, one-dimensional flux path, which is comparable to or better than the very best 2D radial flux motors on the market.
Most permanent magnet motors these days work with a radial flux topology. Here, the magnetic flux loop starts at a permanent magnet on the rotor, passes through the first tooth on the stator, then flows radially along the stator. It then passes through a second tooth to arrive at the second magnet on the rotor. In a dual-rotor axial flux topology, the flux loop starts at the first magnet, passes axially through a stator tooth, and immediately arrives at the second magnet.
Because the flux path in axial flux machines is one-dimensional, grainoriented electrical steel can be used. The steel makes it easier for the flux to pass through, and this results in the efficiency gain.
Radial flux motors have traditionally used distributed windings, where as much as half the winding are not active as they overhang the magnets. Designs have improved winding methods, as the coil overhang results in additional weight, cost, electrical resistance and more heat wasted.
Axial flux machines have far fewer coil overhangs, and some designs use concentrated or segmented windings that are fully active. Segmented stator radial machines introduce additional loses owing to breakage of the flux path in the stator, but that is not a problem for axial machines. The design of the coil windings is a key area where suppliers can differentiate between themselves.
However, axial flux motors pose some serious design and production challenges that have made them far more costly than their radial counterparts, despite the technological advantages. Radial motors are well-understood, and manufacturing methodologies and machinery are readily available.
Reliability is paramount in the automotive industry, and providing evidence of the reliability and robustness of the different axial flux motors to convince manufacturers of their suitability for mass manufacturing has been a challenge. That has led axial motor suppliers to carry out their own extensive validation programmes, with each being able to demonstrate that the reliability of their motors is no different from that of traditional radial flux types. 041b061a72