A method for locating the initial position of the rotor magnetic poles of a salient-pole three-phase permanent magnet synchronous motor

Abstract

The invention relates to a method for positioning the initial position of a rotor magnetic pole of a salient-pole three-phase permanent magnet synchronous motor, which solves a problem that the existing method for positioning the initial position of the rotor magnetic pole of the salient-pole three-phase permanent magnet synchronous motor is long in positioning time and low in positioning accuracy. The method comprises the steps of 1, determining a PWM period TPWM capable of reaching the saturated phase current; 2, collecting unsaturated phase current of a phase A, a phase B and a phase C of the motor by adopting an unsaturated collection control period T1, wherein the unsaturated collection control period T1 equals to 0.2TPWM-0.25TPWM; 3, calculating an initial direction angle [Theta]0rawof the rotor magnetic pole by using a collection result of the step 2; 4, selecting a phase close to the initial direction angle [Theta]0raw to load phase current taking the PWM period TPWM as a control period, and collecting the saturated phase current of the phase; and 5, calculating a polarity offset angle [Theta]0offset, and calculating [Theta]0 according to a formula that [Theta]0=[Theta]0raw+[Theta]0offset. The method for positioning the initial position of the rotor magnetic pole of the salient-pole three-phase permanent magnet synchronous motor does not need complicated high-frequencyvoltage injection or sequence pulse voltage injection, and is simple to implement, high in positioning speed and high in positioning accuracy.

Description

technical field [0001] The invention belongs to the field of motors, and relates to a motor control method, in particular to a salient pole type three-phase permanent magnet synchronous motor rotor magnetic pole initial position positioning method. Background technique [0002] The salient pole three-phase permanent magnet synchronous motor has the characteristics of high power density, convenient control, good control performance, and large speed regulation range. However, when the motor is started, it is necessary to know the initial position of the motor rotor magnetic poles, otherwise it will fail to start. Therefore, encoders are generally used to detect the position of the motor rotor magnetic poles. Absolute encoders or incremental encoders with UVW can solve the problem of motor Start-up problem, but it brings an increase in cost, and the incremental encoder with UVW, the initial positioning accuracy of the magnetic pole is only + / -30° electrical angle. [0003] The...

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Problems solved by technology

[0004] The purpose of the present invention is to solve the problem of long positioning time and low positioning accuracy of the existing method for initial positioning of the rotor magnetic pole position of the salient pole type three-phase permanent magnet synchronous motor, and provides a salient pole type three-phase permanent magnet synchronous motor rotor magnetic pole initial positioning method. The position positioning method, in this method, the motor magnetic field is in an unsaturated state when the basic voltage vector voltage applied to the motor winding is short, and the structural saliency effect of the motor is used to construct a calculation formula to obtain the initial direction angle of the motor rotor magnetic pole, Then, by prolonging the duration of the voltage vector, the magnetic field of the motor exhibits a saturated saliency effect, and the positive and negative directions of the magnetic poles are corrected, so that the initial positioning of the rotor magnetic pole position of the salient pole three-phase permanent magnet synchronous motor can be effectively and quickly realized, which is a codeless motor. The initial positioning of encoder control or incremental encoder provides a valid starting position signal

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