| 摘要: |
| 为了提高LCL滤波的双馈式风电网侧变流器在电网电压不平衡情况下的工作性能，通过对变流器在上述条件下的数学模型进行理论分析，提出了基于LCL滤波器的不平衡电流指令算法，并提出了在同步旋转dq坐标系下采用PI和重复控制器并联结构的电流复合控制方案。利用所提控制策略，可有效降低电网电流中的低次谐波含量，实现正负序电流的无差跟踪控制，提高直流电压的稳定性。为了抑制LCL滤波器在系统暂态时产生的振荡问题，采取了电容电流抑制谐振的有源阻尼方案。通过一台5 kW样机实验验证了理论的正确性。 |
| 关键词: 不平衡电网电压 风力发电 滤波器 变流器 复合控制 电路拓扑 |
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| Control strategy of grid-side converter with LCL filter in doubly-fed wind power system under unbalanced grid voltage |
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ZHANG Xianping
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Guodian United Power Technology Co.，Ltd.，Beijing 100039，China
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| Abstract: |
| The mathematical model of grid-side converter with LCL filter is built and analyzed to improve its performance in doubly-fed wind power system under unbalanced grid voltage conditions. An unbalanced grid current instruction algorithm based on LCL filter and a compound current control strategy based on the parallel PI controller and repetitive controller in synchronous rotating dq frame are proposed，which effectively reduces the low-order harmonics of grid current，achieves the positive／negative current tracking without steady-state error and enhances the DC voltage stability. The scheme of active damping by filter capacitor current is applied to suppress the transient resonance of LCL filter. Experiment with a 5kW prototype verifies the correctness of the proposed control strategy. |
| Key words: unbalanced grid voltage wind power electric filters electric converters compound control electric network topology |
