Position sensorless brushless DC motor phase compensation device and compensation method

Abstract

The invention discloses a phase compensation device and method of a brushless direct-current motor without a position sensor. The phase compensation device comprises a power source, a three-phase rectifier bridge, an RC filter circuit, a single-chip microcomputer, a compensation circuit and the brushless direct-current motor. The power source is connected with the three-phase rectifier bridge, the output end of the three-phase rectifier bridge is connected with the brushless direct-current motor and the RC filter circuit in parallel, the RC filter circuit is connected with the single-chip microcomputer, and the single-chip microcomputer is connected with the compensation circuit. The compensation circuit comprises a three-bit A / D (analog / digital) converter, a 3-8 decoder and a resistance bridge in serial connection, wherein the resistance bridge is connected with the brushless direct-current motor and the RC filter circuit in parallel. The compensation method includes transmitting motor revolving speed detected to the single-chip microcomputer, decoding voltage signal output and finally controlling change of a phase compensation angle. The phase compensation device and method solves the problem that the RCX filter circuit of a conventional position-sensorless counter-electromotive force method cannot realize 30 degrees of accurate time delay and by a time delay method of five speeds, the speed change of the phase compensation angle can be accurately tracked.

Description

technical field [0001] The invention belongs to an electronic control method and a control device, in particular to a position sensorless brushless DC motor phase compensation device and method. Background technique [0002] The research on sensorless brushless DC motor can simplify the internal structure of the motor, reduce manufacturing and maintenance costs, and avoid failures caused by damage to the position sensor. The basic principle of the traditional "rotor position measurement method based on measuring the back electromotive force" is to delay the 30° time delay of the collected 3-way terminal voltage signals through deep RC filtering. Whether the 30° time delay is accurate is of great importance to the normal and stable operation of the system Due to the large fluctuation range of the frequency of the three-phase terminal voltage under different operating states such as motor start, low, medium, and high speed, the traditional hardware RC filter circuit cannot ach...

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Problems solved by technology

The basic principle of the traditional "rotor position measurement method based on measuring the back electromotive force" is to delay the 30° time delay of the collected 3-way terminal voltage signals through deep RC filtering. Whether the 30° time delay is accurate is of great importance to the normal and stable operation of the system Because the frequency of the three-phase terminal voltage fluctuates in a relatively large range under different operating states such as motor start, low, medium, and high speed, the traditional hardware RC filter circuit cannot achieve an accurate delay of 30°

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