Electrical excitation brushless DC motor asymmetric groove rotor structure

Abstract

The invention provides an electrical excitation brushless DC motor asymmetric groove rotor structure. According to the excitation of a brushless DC motor, through adjusting the size of external excitation current, the output torque and speed of the motor are adjusted, a large torque can be outputted in a low speed, a high rotation speed can be obtained, and the motor is the ideal driving motor of an electric vehicle. The magnetic field waveform of the brushless DC motor must be a trapezoidal wave (also called a rectangular wave), and the upper side width of the magnetic field trapezoidal wave must reach 120 electrical degrees. According to a traditional slot rotor structure, the notch is in the center line of a slot and is close to the magnetic center, the width of a generated magnetic field is small, and the requirement of the 120 electrical degrees of the upper side width of the magnetic field trapezoidal wave is difficult to satisfy. According to the electrical excitation brushless DC motor asymmetric groove rotor structure, a rotor excitation winding slot is close the edge of a magnetic pole and is processed to be an asymmetric structure, the notch is not in the slot center line but is deviated to a magnetic pole edge, the condition that the magnetic field generated by an excitation winding has the trapezoidal wave magnetic field needed by the motor is ensured, the upper side width of the magnetic field trapezoidal wave is larger than 120 electrical degrees, and the good performance of the excitation brushless DC motor can be ensured.

Description

Technical field [0001] The invention relates to a DC motor, in particular to an electric excitation brushless DC motor. Background technique [0002] The electric excitation brushless DC motor can adjust the output torque and speed of the motor by adjusting the magnitude of the external excitation current, so that the external characteristics of the motor conform to the load characteristics of the electric vehicle. It can output large torque at low speed and has higher speed. This kind of motor saves the expensive rare earth permanent magnet, the cost will be significantly reduced, the reliability will be improved, and it can be applied to places with high temperature. The electric excitation brushless DC motor has good speed regulation performance, and will become the preferred motor in the field of electric vehicles in the future. [0003] In order to make the brushless DC motor have high torque characteristics, the magnetic field waveform of the brushless DC motor must ...

AI Technical Summary

Problems solved by technology

If the electric excitation brushless DC motor adopts this symmetrical slot structure, the notch is located at the center line of the slot, the width of the magnetic pole formed between the two excitation coil slots is small, and the width of the generated magnetic field is small, which is difficult to meet the upper width of the trapezoidal wave of the magnetic field. Reaching the requirement of 120 electrical angles, there is no guarantee that the electric excitation brushless DC motor has good performance

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