无刷双馈发电机(brushless doubly-fed reluctance generator,BDFG)在风力发电领域有着广阔的应用前景.基于虚拟同步发电机(virtual synchronous generator,VSG)的无刷双馈风电系统具有一定的电网频率支撑能力,但在电网电压不平衡工况下运行性能较差.提出了一种不平衡电网工况下无刷双馈风电系统的虚拟同步发电机策略,来降低不平衡的电网电压对BDFG系统的影响;其核心思想为使用原有BDFG-VSG来控制正序分量,在功率绕组正向同步旋转坐标系下使用基于降阶广义积分器(reduced order generalized integrator,ROGI)的直接谐振控制调节负序分量.详细分析了电网电压不平衡对BDFG各电量的影响,据此提出了 5种可供选择的优化目标,最后通过仿真验证了该策略的有效性.所提出的策略可抑制不平衡电网工况下BDFG的各电量中的负序分量或二倍频分量,无需计算负序电流的参考值,对电网具有友好性.
Control of BDFG Wind Turbine Based on Virtual Synchronous Generator Under Unbalanced Grid
Brushless doubly-fed reluctance generators(BDFG)have shown a great application potential in the wind power generation.The brushless doubly-fed wind power systems based on the virtual synchronous generators are capable of supporting the grid frequency,but they often operate relatively poorly under the unbalanced grid voltage conditions.To mitigate the impact of the unbalanced grid voltages on the BDFG systems,an improved virtual synchronous generator(VSG)control strategy for BDFG systems is proposed in this paper.The core idea is to use the original BDFG-VSG to control the positive sequence component,and to use the direct resonant control based on a reduced-order generalized integrator(ROGI)to regulate the negative sequence component in the reference frame of the positive sequence components.The paper presents a detailed analysis of the effects of the unbalanced grid voltages on the BDFG and proposes five optimization targets for consideration.Simulation results demonstrate the effectiveness of the proposed approach.The approach presented in this paper aims to suppress the negative sequence components or the twice grid frequency components in the BDFG when operating under an unbalanced grid condition.This approach obviates the need for calculating a reference value for the negative sequence current,which is grid friendly.
brushless doubly-fed reluctance generatorunbalanced gridvirtual synchronous generatorreduced order generalized integratordirect resonant control
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维普
