Influence of armature winding on the performance of permanent magnet synchronous drive motor
The armature winding of the permanent magnet synchronous drive motor can be divided into a distributed winding and a concentrated winding according to the shape of the coil winding and the method of the weaving. According to the number of slots per phase per motor q = knife (print m), it can be divided into integer slot winding and fractional slot winding.
The use of fractional or integer slots is considered in terms of motor performance and production process. The use of fractional-slot windings has the following advantages over integer-slot windings:
1) The average number of slots under each pair of magnetic poles is greatly reduced, and a larger number of small slots are replaced by a smaller number of large slots, and the number of armature punching slots is small. The manufacturing process of the armature core is relatively simple, and at the same time, the space occupied by the slot insulation can be reduced, which is beneficial to increase the slot full rate and thereby improve the performance of the motor.
2) When the fractional slot is generally used, the end of the motor coil is short, which not only reduces the resistance of the motor winding by saving copper wire, but also reduces the copper loss of the motor under the same conditions, improves the efficiency of the motor and reduces the temperature rise.
3) When the chute is not used, the short-distance and distribution effects of the windings can be passed. Improve the sinusoidality of the back EMF waveform, which in turn reduces the torque ripple and noise of the motor.
4) When the pitch l, =1 (fractional slot concentrated winding) is adopted, automatic winding can be used, which not only improves labor productivity, simplifies the weaving process and wiring, but also reduces the cost. At the same time, each coil only Wrapping on one tooth shortens the circumference of the coil and the length of the winding end. Further reducing the amount of copper used, the ends of the respective coils do not overlap. It is not necessary to provide phase insulation.
5) Reasonable selection by the cooperation of the pole slots. The use of the fractional-slot concentrated winding relative to the integer-slot winding is more effective in reducing the cogging torque and increasing the output power, and the weak magnetic expansion capability is also improved.
The main disadvantages of fractional-slot windings compared to integer-slot windings are: strict constraints on the number of slots and poles, slightly lower winding coefficients, higher winding inductance, harmonics in the armature reaction magnetomotive force, and rotor eddy current losses. And noise. At present, it is effective to select the pole groove with lower magnetomotive force harmonics, the rotor yoke to reduce the eddy current loss by lamination, the permanent magnet material with high resistivity, the proper increase of air gap, and the adjustment of the slot width. Make up for the inadequacies of the fractional slot windings.
According to the above analysis, the fractional slot winding can effectively improve the slot full rate, reduce the copper loss of the motor, and reduce the cogging torque, both in terms of performance indicators and economical defects. More suitable for permanent magnet synchronous drive motors.
