Low-speed and zero-speed rotor position observation system for permanent magnet brushless DC motor

Abstract

The invention relates to a low-speed and zero-speed rotor position observing system for a permanent magnet brushless direct current motor. Based on a permanent magnet brushless direct current motor drive control system composed of an alternating voltage, a rectifying circuit, a filter capacitor, a three-phase inverter and a permanent magnet brushless direct current motor, the observing system comprises a high-frequency current injection circuit and a three-phase winding phase voltage collection circuit; the three-phase winding phase voltage collection circuit is divided into three routes to be connected with a band-pass filter so as to extract high-frequency components in the three-phase winding phase voltage; the band-pass filter is sequentially connected with a multiplying unit, a low-pass filter, a summator, a coordinate transformation link and the like to obtain correlated variables of the observing errors of the rotor position angle, and the coordinate transformation link is further sequentially connected with a PI controller and an integrator, and output in the steady state of the integrator is the observing value of the rotor position angle. The system can accurately and reliably obverse the position of the rotor when the permanent magnet brushless direct current motor runs at the low speed and the zero speed under the two-phase breakover mode, and the system is wide in application range and low in implementation cost.

Description

technical field [0001] The invention relates to the technical field of motor rotor position detection, in particular to a low-speed and zero-speed rotor position observation system of a permanent magnet brushless DC motor in a two-phase conduction mode. Background technique [0002] Due to its simple structure, large output and high efficiency, the permanent magnet brushless DC motor (BLDCM) has been widely used in the fields of national defense, aerospace, robotics, industrial process control, precision machine tools, automotive electronics, household appliances and office automation. The research on its high-performance control strategy has important theoretical significance and practical value. At present, there are two main researches on its control strategy: current closed-loop PWM control and direct torque control (DTC). [0003] Compared with the traditional sine wave permanent magnet synchronous motor, the counter electromotive force of the permanent magnet brushles...

AI Technical Summary

Problems solved by technology

These auxiliary starting methods restrict the load capacity of the motor to a certain extent, and also restrict the operation of the drive system at extremely low speeds.

2) The effective speed regulation range is narrow for position sensorless operation

[0006] Looking at the current research status of position sensorless technology for permanent magnet brushless DC motors in two-phase conduction mode, the technology for motors in the middle and high speed ranges is relatively mature, but the research on low speed and zero speed position sensorless technology is still blank. and also a difficulty

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