An air gap field oriented control method and system for an electrically excited synchronous motor

Abstract

The invention discloses an air-gap field oriented control method and a system of an electrically excited synchronous motor, comprising the following steps: obtaining t-axis component of a given statorcurrent and a given air-gap flux linkage of the electrically excited synchronous motor, and obtaining m-axis component of the given stator current according to a unit power factor control relation; The phase angle and amplitude of the air-gap flux linkage are obtained by observing the flux linkage of the motor with the full-order flux linkage observation model. According to the phase angle of theair-gap flux linkage and the t-axis and m-axis components of the stator current, the pulse vector corresponding to the three-phase inverter connected with the motor is obtained by the vector controlalgorithm, so as to control the on-state of the switch in the three-phase inverter according to the pulse vector. The excitation voltage of the motor is controlled according to the magnitude of the air-gap flux linkage so that the magnitude of the air-gap flux linkage tracks a given air-gap flux linkage value. The present application can realize unity power factor control, and based on a full-order flux linkage observation model, the air gap magnetic field is accurately oriented, is less affected by parameters, can realize complete decoupling control, and has better performance.

Description

technical field [0001] The invention relates to the field of high-power speed regulation, in particular to an air-gap magnetic field-oriented control method and system of an electrically excited synchronous motor. Background technique [0002] Electric excitation synchronous motor, as a typical synchronous motor, has been widely used in high-power speed regulation systems. At present, there are two main control methods for electric excitation synchronous motors: vector control based on field orientation and direct torque control based on torque. The vector control of electric excitation synchronous motor mainly includes: rotor field oriented control, air gap field oriented control, stator field oriented control and damping field oriented control. Among these kinds of field oriented control, the mathematical model of rotor field oriented control is the simplest, so it is more commonly used. [0003] In the prior art, under the rotor field oriented control mode, the flux lin...

AI Technical Summary

Problems solved by technology

It can be seen that the traditional rotor field-oriented control cannot fully realize the decoupling control of flux linkage and torque, and the orientation accuracy is greatly affected by parameters, resulting in poor dynamic control performance

In the air-gap magnetic field oriented control mode, as long as the air-gap magnetic field remains constant, the complete decoupling of flux linkage and torque can be achieved, but the orientation accuracy of the air-gap magnetic field is also low, and unity power factor control cannot be realized. lead to lower efficiency of the overall system

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