Method for detecting stochastic resonance of weak back electromotive force signal of brushless direct-current motor

Abstract

The invention relates to a method for detecting stochastic resonance of a weak back electromotive force signal of a brushless direct-current motor. The method comprises the following steps of: (1) under the static or low-speed condition of the motor, applying test pulse to a stator coil of the motor, and detecting a back electromotive force signal of the motor with a singlechip; (2) inputting theback electromotive force signal and a noise signal into a stochastic resonance system together, and outputting a zero crossing signal with the stochastic resonance system; and (3) detecting the zero crossing signal output by the stochastic resonance system with the singlechip, and outputting a motor commutation signal to the motor. In the invention, the weak back electromotive force signal which is submerged in noise is enhanced and the noise is remarkably reduced by using the stochastic resonance system, so that aim of extracting a weak back electromotive force zero crossing signal of the motor is fulfilled. The zero crossing signal is more accurate, so that the running efficiency of the motor can be increased, the reverse rotation of the position sensor-free brushless direct-current motor in the starting process is avoided, and the stability and high efficiency of the motor are ensured in the starting and running processes.

Description

technical field [0001] The invention relates to the detection field of electronic signals, in particular to a stochastic resonance detection method for weak counter electromotive force signals of a brushless DC motor. [0002] Background technique [0003] The brushless DC motor needs the position signal of the rotor during operation to control the commutation of the power tube in the inverter, so as to realize the synchronous operation of the stator magnetic field and the rotor. Most brushless DC motors rely on shaft position sensors or other types of detecting position detectors to detect the rotor position. These sensors not only increase the cost, but also make the system connection more complicated, and due to the defects of the sensor itself, make the The reliability of the entire system cannot be guaranteed. [0004] When the Hallless brushless DC motor controller is running at a high speed, it indirectly obtains the position of the motor rotor by detecting the zero...

AI Technical Summary

Problems solved by technology

However, when the motor is started and running at low speed, the back electromotive force is very small, the zero crossing point cannot be measured or is difficult to measure, and the position of the motor rotor cannot be determined by the back electromotive force method

[0005] At present, the focus of weak signal detection technology is focused on suppressing noise. However, when the noise spectrum is close to the signal spectrum, the useful signal will inevitably be damaged while suppressing the noise.

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