考虑直压波动的双馈风机转子侧改进控制的研究

Research on Improving Control of the Rotor Side of the Doubly-fed Wind Power Generator with DC Voltage Fluctuation

双馈风力发电机(以下简称双馈风机)在传统转子侧矢量控制中,控制的前提是默认直流母线电压(以下简称直压)恒定,而没考虑其波动。当直压波动时,对象模型中的功率也会随之波动而导致输出不平稳,同时,在工程实际中,为保证直压的稳定,一般采用较大的电容,会造成较大的成本消耗。因此本文提出针对直压波动的转子侧改进控制算法,引入前馈控制,消除直流母线电压波动造成的影响,保证直压波动情况下对象模型功率的稳定输出,且运用改进控制后,可降低电容容量,节约工程成本。最后基于PSCAD/EMTDC仿真对所提出的改进控制策略进行仿真验证,与传统控制策略进行对比分析,结果表明:本文提出的转子侧改进控制策略控制精度高,响应迅速,在直压波动时可降低功率的波动,输出更平稳,验证了所给控制策略的正确性及有效性。

The control objective of the rotor side of the doubly-fed wind power generator is to realize the decoupling of the power and the stable output, while the stability of the object model is determined by the stability of the DC bus voltage. In the traditional rotor side vector control, control on the premise is default DC bus voltage constant, without consideration of the bus voltage fluctuations. When the DC voltage fluctuations, the object model of the power will fluctuate and steady output of power will be impacted at the same time. In the practical engineering, in order to guarantee the stability of the DC voltage, the larger capacitance is usually used, which will result in greater cost. In this paper, we propose a modified control algorithm for the rotor side of the DC voltage fluctuation. The feedforward control is introduced to eliminate the influence caused by the fluctuation of the bus voltage. Finally, based on the PSCAD/EMTDC simulation, the proposed control strategy is verified by simulation and compared with the traditional control strategy. The results show that the improved control strategy of rotor side has high accuracy and fast response, which can reduce the power fluctuation and stabilize the output, and verify the correctness and effectiveness of the proposed control strategy.