A Method for Precise Estimation of Rotor Position of Electrically Excited Doubly Salient Motor

Abstract

The invention discloses a method for estimating a precise position of an electro-magnetic doubly salient motor rotor, and belongs to the technical field of motor control. The method comprises the following steps: firstly, sequentially injecting detection pulses A+C, B+A and C+B of a same width into an armature winding through a three-phase full-bridge converter, and respectively sampling and detecting response current ac, ba and cb when the pulses are completed; respectively calculating two-phase serial connection self-inductance values Lac, Lba and Lcb according to response current; judging a sector area of the rotor according to the size relationship of two-phase serial connection self-inductors; finally, according to geometric similar relationships of an 'inductance rectangle' consisting of the rotor sector areas and the two-phase serial connection self-inductors, establishing the precise position of the rotor. In addition, according to two times of adjacent rotor position estimation and two estimation time intervals, a current rotation speed of the motor can be obtained. By adopting the method, precise position estimation on the rotor in the starting process can be achieved without extra hardware circuits, phase conversion precision can be ensured, and the starting performance of a position-free sensor of a system is improved.

Description

technical field [0001] The invention relates to a method for estimating the precise position of a rotor of an electrically excited double salient pole motor, belonging to the technical field of motor control. Background technique [0002] As a new type of special motor, electrically excited doubly salient motor has the advantages of simple and reliable structure, flexible control, and good fault tolerance performance. It has attracted extensive attention in the fields of aviation and new energy power generation. The installation of mechanical position sensors in traditional electrically excited double salient motor systems not only increases the volume cost of the system, but also reduces the reliability. Therefore, its position sensorless control strategy has important research value. The research on the position sensorless control strategy of pole motor is still in its infancy. The back EMF method is the most commonly used position sensorless control method at present, bu...

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Problems solved by technology

However, there is a big difference in the inductance characteristics between the permanent magnet doubly salient motor and the electrically excited doubly salient motor, and this method can only estimate the sector where the rotor is located, and cannot achieve accurate position estimation

[0006] At present, the rotor position estimation of many electrically excited double salient pole motors in the low-speed stage is mostly realized by injecting detection voltage pulses, but this method can only estimate the sector where the rotor is located, and cannot achieve accurate rotor position estimation, and this method has inevitable problems. The commutation delay affects the starting performance of the motor

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