Excitation control method of independent generating system of brushless doubly-fed machine under asymmetric load

Abstract

The invention discloses an excitation control method of an independent generating system of a brushless doubly-fed machine under an asymmetric load. On the basis of positive-sequence and negative-sequence dual dq coordinate systems, a power winding (PW) voltage of a brushless doubly-fed machine is decomposed into a positive-sequence component and a negative-sequence component; a PW voltage positive-sequence component controller and a PW voltage negative-sequence component controller are used for adjusting amplitudes and frequencies of the PW voltage positive-sequence component and the PW voltage negative-sequence component so as to obtain a needed control winding (CW) voltage positive-sequence component and a needed CW voltage negative-sequence component; the CW voltage positive-sequence component and the CW voltage negative-sequence component are added to obtain a final CW voltage given value; according to the given value, a PWM modulation signal and thus an inverter is driven to control the CW; and then the amplitude and frequency of the PW voltage positive-sequence component track the given value respectively and the PW voltage negative-sequence component amplitude converges to zero. With the method, the constant-frequency and constant-voltage generating function of the independent generating system of the brushless doubly-fed machine under the asymmetric load can be realized. Moreover, the control method has advantages of simpleness, high reliability and high robustness.

Description

technical field [0001] The invention belongs to the technical field of power generation control of brushless double-fed motors, and more specifically relates to an excitation control method of a brushless double-fed motor independent power generation system under asymmetric load conditions. Background technique [0002] The brushless double-fed motor is a new type of AC induction motor, which consists of two sets of stator windings with different pole pairs and a set of rotor windings. The basic principle is that the specially designed rotor makes the two sets of stator windings produce different pole pairs of rotating magnetic fields to interact indirectly, and the interaction can be controlled to realize energy transfer. The two sets of stator windings of the brushless doubly-fed motor are respectively called power winding (hereinafter referred to as PW) and control winding (hereinafter referred to as CW). It has the characteristics of asynchronous motor and synchronous m...

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Problems solved by technology

In the control method provided by the invention patent of an excitation control device for a brushless doubly-fed motor independent power generation system (application number: 201510391869.8), the control of the CW current is based on a single rotating coordinate system. Essentially, this method cannot The positive sequence component and negative sequence component in the PW voltage are controlled simultaneously

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