Rotor position detection method of brushless direct current motor without sensor

Abstract

The invention discloses a rotor position detection method of a brushless direct current motor without a sensor. The rotor position detection method of the brushless direct current motor without the sensor comprises a detection method of a rotor start position and a detection method of a rotor position after the motor rotates. According to the detection method of the rotor start position, current relative positions of a coil magnetic field and a permanent magnetic field can be judged according to a law of variation of motor coil magnetic flux along with the permanent magnetic field, specially, symmetric voltage Uvu and Uuv, Uvw and Uwv, and Uuw and Uwu with equal pulse width and the same voltage value are connected with three phase circuits v, u and w of the motor in pairs, the voltage can not enable a rotor of the motor to deflect, the voltage or current of brushless direct current motor coil three phases is sampled, and current relative positions of coil of the rotor and the permanent magnetic field when the motor is started can be estimated according to a voltage circuit equation. According to the rotor position detection method of the brushless direct current motor without the sensor, the position of the rotor can be detected without the requirement for motor rotation, and therefore a current blind starting mode of the brushless direct current motor without a Hall sensor is replaced.

Description

technical field

[0001] The invention relates to a method for detecting the rotor position of a DC brushless motor, in particular to a method for detecting the rotor position of a sensorless DC brushless motor. Background technique

[0002] Nowadays, with the promotion and popularization of brushless motors, the inherent problems also appear at the same time, which also makes the majority of users feel a little headache. Because the Hall installation is cumbersome, and 80% of the faults of the brushless motor are caused by the Hall element, and even a considerable part of the fault misjudgment of the brushless motor controller is also caused by the Hall element. The performance and life of the Hall element will be affected by electromagnetic interference in the circuit, thus affecting the normal operation of the entire circuit system. Due to its low withstand voltage value, it is very easy to cause breakdown when the motor coil leaks electricity. At the same time, the insta...

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