Control device of brushless doubly-fed machine and control method thereof

Abstract

The invention, which belongs to the motor control field, relates to a control device of a brushless doubly-fed machine and a control method thereof. Compared with two traditional level inverter circuits, a main circuit and a three-level inverter of a diode clamp have obvious advantages; a phase voltage output is changed from a two-level mode into a three-level mode; a line voltage is increased from a three-level mode to a five-level mode; and an amplitude of each of the level is reduced from an original whole direct current bus voltage to a half of direct current bus voltage, so that an output level is reduced to half of the original level. If the number of switch devices in series connection in each unit is increased, more levels can be generated in an output voltage waveform, so that the output waveform can better approach a standard sinusoidal waveform. According to the method provided in the invention, decoupling components Udc and Uqc of a controlled winding voltage of the brushless doubly-fed machine can be respectively controlled, so that an active power and a reactive power can be respectively controlled; and thus, the power factor is adjustable and energy can be effectively utilized.

Description

technical field [0001] The invention belongs to the technical field of motor control, and in particular relates to a brushless doubly-fed motor control device and a control method thereof. Background technique [0002] Brushless doubly-fed motor is a new type of motor developed in recent years. It is developed from the cascaded motor invented by Hunt. Brushes and slip rings increase the reliability of the motor operation and reduce the maintenance cost of the motor. At the same time, the variable frequency power supply only needs to supply power to the control winding, which reduces the cost of the controller. Due to its structural characteristics, it is widely used in renewable energy such as wind power generation, wind power generation, variable head hydropower generation, and tidal power generation. [0003] The brushless doubly-fed motor consists of two sets of stator windings and one set of rotor. The two sets of stator windings are power windings and control windings ...

AI Technical Summary

Problems solved by technology

[0004] Since the brushless doubly-fed motor is converted from two induction motors with different pole numbers connected in series, its power flow relationship can be analyzed with reference to the induction motor. However, since the brushless doubly-fed motor has two sets of stator windings, when its In a steady state of operation, the magnetic field established by the two sets of stator windings in the rotor will produce a coupling effect, so it has its own complexity compared to ordinary AC induction motors

Therefore, it is difficult to control the power of the brushless doubly-fed motor.

[0005] The existing brushless doubly-fed motor adjusts the power factor by controlling the voltage amplitude at the stator winding end, resulting in low quality of power grid transmission when the brushless doubly-fed motor is in the power generation state

[0006] In the existing brushless double-fed motor power control system, most of them use PID control to adjust the difference of closed-loop control to obtain the required parameters, which has the advantages of simple algorithm, high reliability, and easy implementation. The traditional PID control algorithm is used in When seeking the optimal values ​​of the three variables Kp, Ki and Kd, the empirical method and the trial and error method are mostly used to adjust the control parameters of the PID controller. This traditional method has obvious control effects in linear systems, but it is different from ordinary Compared with the brushless brushless motor, the AC induction motor has many unfavorable factors such as complex structure, large harmonic content, complex control equation, complex control method, and the influence of motor parameter changes on the control of the motor. did not achieve very satisfactory results

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