Sensorless control method of permanent magnet synchronous motor in wide rotating speed scope

Abstract

The invention discloses a sensorless control method of a permanent magnet synchronous motor in a wide rotating speed scope and belongs to the field of permanent magnet synchronous motor technology. The method comprises steps of acquiring output current of the motor and establishing a slip form observer for estimating a stator current desired value; correcting weighting coefficient according to difference between the stator current desired value and the actual value and estimate value between the rotator angular velocity and rotor position; determining estimating value between the rotator angular velocity and rotor position according to the weighing coefficient, a low-speed position estimate value and a high-speed position estimate value; determining stator voltage reference value according to estimate value of the rotator angular velocity and the rotator position and the actual value of stator current; and obtaining three-phase inverter driving signal using space voltage vector modulation technology. The motor operates by the driving signal until the rotator angular velocity is converged to the estimate value. According to the invention, precision of rotating speed estimation, stability of the system and precision of a switching process are increased, fluctuation of rotating speed and shaking of the motor in the switching process of the rotating speed are reduced and the switching process is smoother.

Description

technical field [0001] The invention discloses a position sensorless control method for a permanent magnet synchronous motor within a wide speed range, and belongs to the technical field of permanent magnet synchronous motor control. Background technique [0002] In the permanent magnet synchronous motor control system, mechanical position sensors (such as photoelectric code discs and resolvers) are generally required to detect the rotor position and speed. However, the existence of the mechanical sensor increases the system cost and increases the system volume. At the same time, because the mechanical sensor has many connections, the complexity of the system is further increased, thereby reducing the reliability of the system and causing difficulties in installation. More prominently, mechanical sensors are easily affected by the working environment, which severely limits the use of permanent magnet synchronous motors in some special occasions with harsh environments. Ther...

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Problems solved by technology

[0004] However, when the speed is switched, the simple weighted average method of the speed is used, which has the disadvantages of large speed estimation error, large speed fluctuation during switching, and easy switching failure.

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