双三相无刷双馈发电机:建模及其控制方法研究

Mathematical Modeling and Control Methods of Dual Three Phase Brushless Doubly Fed Generators

提出了一种双三相无刷双馈发电机。该电机定子上除了常规的三相功率绕组外,还有两套空间上互差30°电角度且中性点独立的控制绕组。建立了该电机的数学模型。令这两套绕组的电流时序上相差30°,则气隙磁势中的5次和7次谐波分量将会被消除,同时基波磁势达到最大。研究了一种电流控制算法,可以实现这两套控制绕组电流相位差30°的控制目标。提出了这两套控制绕组载波移相90°的PWM控制方法,可以有效降低功率绕组输出电压波形中的高次谐波。提出了一种无位置编码器控制算法,在并网条件下可实现功率绕组有功电流和无功电流的控制。研制了一套30k VA绕线转子双三相无刷双馈发电机控制系统及实验装置。通过大量的仿真和实验研究,验证了所提出控制方法的正确性。

A dual three phase brushless doubly fed generator （BDFG） is presented in this paper, which has two sets of control windings and one set of power windings in the stator iron core. The two sets of control windings are spatially shifted by 30° electrical degrees with isolated neutral points. The mathematical model of dual three phase BDFG is established in this paper. When the current phase angle of two sets of control windings shifts 30°, the 5th and 7th harmonic components of the air gap MMFs will be eliminated, and the fundamental MMF can arrive its maximum value. A current control method is proposed in this paper, which can realize 30° current phase angle difference of two sets of control windings. The PWM control method of carrier phase shift 90° of the two sets of control windings is studied, which can effectively reduce the high order harmonic components of the output voltage of the power winding. An encodedess master-slave control algorithm is proposed, which can control the amplitude of the power winding current under the condition of grid connected generation, and at the same time, the reactive current of the power winding can be controlled to zero. A 30kVA dual three phase brushless doubly fed generator, its control system and experimental platform are developed. The simulation and experimental results are given in this paper, and the correctness of the proposed control method is confirmed.