Improve motor power density by flat wire card winding
In this compressor product of Denso, in addition to the deep integration technology of the motor and controller, the flat wire issuance technology is also adopted.
As the compressor changes from a fixed frequency to a variable frequency direction, the switching frequency of the controller is increased, and the resulting voltage, current surge and skin effect affect the insulation performance and efficiency of the winding, thereby reducing the power density of the winding. . Therefore, there is an article on the motor winding that can be done. The flat line came into being.
What is the flat line?
As the name implies, the flat wire uses a flat copper wire for the windings in the motor. The winding is first made into a shape similar to a hairpin. Then, it is inserted into the stator slot, and the end of the clamping method is welded at the other end.
The difference between the use of the flat wire card and the round wire differs in the shape of the copper wire.
1. The flat wire is conducive to the improvement of the motor slot full rate. The slot roundness of the general round wire motor is about 40%, and the slot full rate of the flat wire motor can reach more than 60%. The increase in slot fullness means that more copper wires can be filled in the same space, resulting in stronger magnetic field strength and higher power density.
2. The contact area between the flat wires is large, compared with the round wire motor, the thermal conductivity is better and the temperature rise is lower.
3. The flat wire motor can increase the copper wire utilization rate by saving the end copper material, thereby achieving the purpose of reducing the cost.
4. Because of the larger aspect ratio of the flat wire, the skin effect caused by high frequency will be weakened.
5. The flat line parasitic capacitance becomes smaller and the current glitch will decrease.
The disadvantage of the flat wire is that it has high molding requirements and is difficult to process, and the production process is complicated.
Reprinted from the network