电流源型光伏并网系统的阻尼方法与控制策略研究

Damping Methods and Control Strategy of Current Source Grid-connected Photovoltaic Inverters

电流源型光伏并网逆变器具有单极升压、输入电流连续等优势,但是交流侧LC滤波器存在谐振尖峰的问题,严重影响了系统的稳定性。首先针对多种阻尼方法展开研究,利用幅频特性曲线得到谐振尖峰抑制效果最优的阻尼方法,并转化成有源阻尼方式。然后对并网电流的双闭环控制系统与参数设计方法展开研究。最后在MATLAB的Simulink平台建立仿真模型,对谐振特性分析及所提出的有源阻尼双闭环控制策略的可行性与正确性进行仿真验证,结果表明控制系统具有良好的稳态与动态性能。

The current source photovoltaic grid-connected inverter has the advantages of unipolar boost and continuous input current,but the resonance peak of LC filter on the AC-side will damage system′s stability.Therefore,various damping methods are studied in this paper,and the damping method with optimum suppression to resonance peak is obtained according to the amplitude-frequency characteristic curves and converted into an active damping method.Then the double-closed-loop control system and the corresponding parameters for grid-connection current are investigated.Finally a simulative test based on the model established on MATLAB Simulink platform verifies feasibility and correctness of the resonance characteristic analysis and the proposed suppression method,indicating satisfactory steady-state and dynamic performance of the control system.