New Era of (Axial Flux) Electric MotorsHyper compact design at low-cost
Electric car market growth gets beyond the expectation, and it continues the trends
Electric motor and instrumentation have huge demands in coming years
Everyone are seeking new technology that can make electric motor:
SMALL, LIGHT on weight, ECONOMIC, LOSSLESS, OPTIMIZED for collaborating systems, INDUSTRILISABLE, PERFORMENCE-EFFCIENT and COST-EFFICIENT
Axial motor flow can provide more torque and power per mass using the same amount energy (current), while smaller
IT’S A SCIENCE FACT
Better and Feasible
Axial motor flow is in any aspects better than radial flow motor
A Global Mathematical Approach
Let us consider a general case in which a moving charge
is submitted to an Electromagnetic Field (E, B )
‘B’–‘0’ ‘0’ ‘E/‘t’
This is the (E, B)force acting on the moving part per unit volume
Field Electromagnetic (Green) exchanges in the Radial Air Gap
Field Electromagnetic (Green) exchanges in the Axial Air Gap
In any case of a Cylindrical Electric Machine (either radial or axial topology), the force depends only on the interaction between the magnetic field produced by the rotor and the stator.
Influence of the geometry
Influence of the geometry
of the rotor on the
value of the torque
What are the geometrical conditions that generate the same torque for the 2 geometries? Supposing we use the same
(same magnets, same iron…. ) so we have the same
in the air gap on optimized machine.
Conclusions on Expression
The geometrical variation generates a higher torque for an axial-flux machine than a radial-one, in other Words, for a given required torque, we can use less magnets and less windings for the axial-flux machine as the magnetic pressure can be diminished.
The real meaning of this formula, is that For a given Torque
, if we canslightly adapt the axial motor flow, the overall volume and the mass of final machine will be less
than a radial-flux-One, even in cases where radial flow machine are considered better!
From radial motor to axial motor, if d5′ could be 10 higher, we can achieve L5′ divided by 2,and save 30 volume.
From radial motor to axial motor, though d6′ is 50′ higher, we can achieve L6′ divided by 3 even 4,still save 30 volume.
The real Interest of an axial-Flux Machine lies in the fact that its torque produced requires less magnetic volume than a radial-flux machine. The mass of the machine will be lower in most applications! The other global parameter to consider is the centrifugal effect: experimental background and studies show that the range speeds of an axial-flux machine is about 15,000 rpm for a diameter of 300 mm
Global system must be analyzed in order to achieve this improvement, but It worth it! Implementing an axial flux machine over a radial one, even some adjustment may be needed, the outcomes are still significant as the global Mass, the global Volume and the global cost of the system can be dramatically reduced.
That is why axial flux machine is better than radial flux machine in most cases scientifically speaking.
Axial Flux Motor: Why So Late?
Despite the benefits on axial flow, at present radial flux motor occupies 99% of market share, as axial flow is challenging
Very high linear speed
Demand on mechanical strength of incorporated magnets can be high
Rotor heats up
Cooling system complex and expensive, Magnet can be demagnetized
Stator structure non-optimized
- Stator is difficult to manufacture at high cadence on production line
- Assembling process should be easily industrialized in production.
WE HAVE SOLUTIONS
Conventional axial rotor flow provides high linear speed for some parts on it, and heats up at high power output, the whole system becomes unstable or even under-power. The need for a better rotor design is obvious.
- Easy to manufacture
- No excited heat from magnetic field
- Strong and durable
Inspired from nature
- Honeycomb grid hold magnet
- No heat, no loss!
- Verified and tested in prototype
- Egg magnets fit perfectly in the grid
- No heat, no demagnetization
- Verified in simulation
Non-optimized stator is difficult to manufacture at high cadence on production line.
- Easy to proceed winding
- Maintain mechanic performance
- Suitable for mass production
- Remove magnetic force difference
- No power loss
- Easily implementation and operation
Two stators one rotor
- Double excitement on rotor
- Less magnets for same performance!
- Cost reduce
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