What are the advantages of disc generators?
A disc generator (also known as an axial flux generator or disc generator) is a type of motor with a different structure from traditional radial flux generators (the most common type of generator with a cylindrical rotor and stator).
It has received widespread attention because it has a series of outstanding advantages, especially in specific application fields.
The following are the main advantages of disc generators:
01
Extremely high power density and torque density
This is the core advantage of disc generators. Its structure is flat, and the magnetic flux path is axial (along the axis), which means that it can generate much greater power and torque than traditional generators with the same diameter and volume.
Result: This enables the motor to be made very compact and lightweight, while outputting powerful power. This is crucial for applications that are extremely sensitive to space and weight.
02
Compact structure, flat appearance
Due to its "disc-shaped" or "pie shaped" design, its axial length (thickness) is very thin, but its diameter is relatively large.
Application: Very suitable for integration into wheel hubs (such as wheel hub motors for electric vehicles), direct drive systems for wind turbines, and various devices with special installation space requirements.
03
High efficiency and low rail loss
The magnetic circuit of the disc generator is short, and many designs use coreless or few core structures (the stator winding is cured with materials such as epoxy resin, without traditional silicon steel sheets).
Benefits:
Eliminating iron loss: Without an iron core, eddy current loss and hysteresis loss are avoided, which significantly improves efficiency during high-speed operation.
Zero cogging effect: The coreless design ensures that there is no change in magnetic resistance when the rotor rotates, resulting in extremely low starting torque and smooth, quiet operation.
04
Excellent dynamic performance and control characteristics
Due to its low moment of inertia (the rotor is usually thin and light), it can accelerate and decelerate very quickly.
Application: Excellent performance in situations that require frequent start stop and rapid response to speed changes, such as industrial servo drives and robot joints.
05
Good heat dissipation performance
The flat shape provides a larger exposed surface area for the heating stator winding, making it easier for heat to dissipate through the casing. If it is a structure with two stators sandwiching one rotor, the heat dissipation effect is better.
Benefit: Allow the motor to operate under long-term high load without performance degradation (demagnetization) due to overheating, thereby improving the motor's overload capacity.
06
Suitable for direct connection with high-speed prime movers
Due to its sturdy rotor and low loss characteristics, the disc generator is very suitable for direct connection with high-speed turbines (such as micro gas turbines) without the need for a reduction gearbox, simplifying the system structure and improving overall reliability.
Summary and Application Scenarios
Combining these advantages, disc generators are particularly suitable for the following fields:
New energy vehicles: wheel hub motors, main drive motors (for example, early models of Tesla Model S/X used axial flux motors provided by Taiwan's Futian Electric).
Wind power generation: Direct drive wind turbines can eliminate bulky gearboxes, improve reliability and efficiency.
Aerospace: a field that requires extremely high weight and power, such as aircraft auxiliary power supplies and unmanned aerial vehicle propulsion systems.
High end industrial equipment: servo motors, robot joints, high-precision CNC machine tools.
High speed micro power generation system: used in conjunction with micro gas turbines.
Of course, it also has some drawbacks:
The manufacturing process is complex and the cost is high, especially for the winding and curing process of ironless stators, which is more complicated than traditional motor manufacturing, resulting in a higher unit price.
The amount of magnetic steel used may be larger: in order to obtain a high magnetic field, sometimes more permanent magnet materials are needed.
Axial magnetic pulling force issue: In a single air gap structure, the rotor will experience strong axial magnetic pulling force, which puts higher requirements on the design and service life of the bearing (but the dual rotor structure can counteract this force).
In summary, the advantages of disc generators are very prominent, especially in modern high-tech applications that pursue lightweight, miniaturization, high efficiency, and dynamic performance. They are demonstrating increasingly strong competitiveness.
