Two-phase brushless direct current motor

Abstract

The invention discloses a two-phase brushless direct current motor which comprises a permanent magnet rotor, a first single-winding stator, a second single-winding stator, a bearing seat and a drivingcircuit board. The first single-winding stator and the second single-winding stator are stacked and installed on the periphery of the bearing pedestal in the axial direction, and the first single-winding stator and the second single-winding stator differ by an electrical angle of 90 degrees in space. Two single-winding stators of the two-phase brushless direct current motor share one permanent magnet rotor, cogging torques generated by the two single-winding stators are just cancelled out, and the total cogging torque is zero. Power supply of the two stator windings differs from each other by90 degrees in phase, and the two stator windings are superposed with the torque generated by the rotor, so that the defects of large torque ripple and small starting torque of a single-phase motor are avoided.

Description

technical field [0001] The invention relates to the technical field of motors, in particular to a two-phase brushless DC motor. Background technique [0002] Currently the most commonly used in the market are single-phase brushless DC motors and three-phase brushless DC motors. Single-phase brushless DC motor (as shown in the patent US10461590B2) has simple structure, simple control circuit and low cost, and is widely used in small power fans; its disadvantage is that there is cogging torque, small starting torque, and torque fluctuation Large, with the increase of frictional resistance after long-term use, there may be a possibility of starting failure. Although the three-phase brushless DC motor does not have the disadvantages of the single-phase motor, the winding structure of the motor is relatively complicated, and the cost of the control circuit is relatively high. [0003] Two-phase motors are ubiquitous in many applications today. For example, in the capacitor fra...

AI Technical Summary

Problems solved by technology

Single-phase brushless DC motor (as shown in the patent US10461590B2) has simple structure, simple control circuit and low cost, and is widely used in small power fans; its disadvantage is that there is cogging torque, small starting torque, and torque fluctuation Large, with the increase of frictional resistance after long-term use, there may be a possibility of starting failure

Although the three-phase brushless DC motor does not have the disadvantages of the single-phase motor, the winding structure of the motor is relatively complicated, and the cost of the control circuit is relatively high.

For example, in the capacitor fractional horsepower motor mentioned in the patent US4520287, its stator is composed of main and auxiliary windings, and the phase difference between the two windings is 90 degrees. If the rotor of this kind of motor is changed to a permanent magnet rotor, the motor will become a Two-phase brushless DC motor, obviously this two-phase brushless DC motor does not overcome the shortcomings of its stator manufacturing complexity, and is not suitable for low-cost applications

The structure shown in the special case two-phase stepping motor (as patent US5929589) as the multiphase stepping motor (as patent US7633191B2) can also be used as a two-phase brushless DC motor, but although this two-phase brushless DC motor has The advantage of simple winding, still has the disadvantage of cogging torque and the disadvantage of high iron loss and low efficiency at high speed

[0004] The invention of the two-phase brushless DC motor, as shown in the patent US8487567B2, is only a principle design, and cannot overcome the shortcoming of cogging torque; its evolutionary version, as shown in the patent US20060244333A1 and the patent US8183733B2, can only reduce the cogging torque Torque cannot be eliminated, and its auxiliary stator teeth will also bring inconvenience to winding

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