A time-varying signal sampling method for identifying the initial position of a sensorless brushless motor

Abstract

A time variable signal sampling method for identifying the initial position of a sensorless brushless motor includes the following steps: 1) selecting a power-up mode, setting cycle index and sampling time, and setting cumulative sum and clearing the cumulative sum; 2) powering up the sensorless brushless motor by short-time voltage pulses with a specified amplitude on the basis of the selected power-up mode, then high-frequency filtering and amplifying the output time variable current sampling signal, AD sampling at the sampling time, and adding the sampling result to the cumulative sum; 3) subtracting 1 from the cycle index, and determining whether the cycle index is 0, executing step 4) if the cycle index is 0, or else executing the step 2); 4) extracting the cumulative sum, and outputting the extraction result. With the method, the sampling result with excellent anti-interference characteristic and high resolution digit can be obtained, without adding a hardware circuit or increasing the resolution of an AD converter. Obvious noise from the motor cannot be generated, and rotation or shaking of the rotor of the motor can be avoided during identification.

Description

technical field [0001] The invention relates to the technical field of motor drive, in particular to a time-varying signal sampling method for identifying the initial position of a non-inductive brushless motor, wherein the non-inductive brushless motor includes a brushless DC motor and a permanent magnet synchronous motor. Background technique [0002] With the continuous improvement and perfection of permanent magnet materials, power MOS tubes and control chip functions, sensorless brushless motors including brushless DC motors and permanent magnet synchronous motors have been increasingly used in the fields of industrial control, home appliances and new energy. The wider the application. Compared with brushless motors with position sensors, sensorless brushless motors without position sensors have significant advantages such as small size, low cost, less susceptible to interference in the control system, and high reliability. [0003] As we all know, in order for the mot...

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Problems solved by technology

[0006] However, in the actual application process, the rotor initial position identification based on the inductance method has the following disadvantages: A) the applied voltage pulse time is short, so the current sampling signal is small; B) there are power interference, CPU core interference and I / O port Equal interference; C) The difference in the inductance of the motor at different positions is small; D) The resolution of the ADC is limited

Due to the objective existence of the above-mentioned unfavorable factors, it is technically difficult to obtain accurate sampling values ​​when using the traditional inductance method to sample the time-varying signal AD, so that the initial position of the rotor cannot be accurately identified, which makes the method of identifying the initial position of the rotor by the inductance method practical. has not been widely used

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