带LCL滤波的SAPF电流控制点选取的研究

摘要

Through theoretical analysis,a selection way of feedback currents for LCL-filter-Based double closed-loop control system with passive damping of Shunt APF was proposed.The range of damp resistor and proportional gain values which make the system stable were extended obviously, when getting the feedback current of inner loop from the inverter side and getting feedback current of outer loop from the grid side,compared to the traditional way of getting feedback current of both internal and external loop from the grid side.It means that the system is more stable with a slight reduction of steady-state accuracy at high frequency harmonics.Since the high frequency harmonics content is less,the reduction is almost negligible.So,only a smaller damping resistor is required to make the system stable and achieve good steady-state accuracy.It reduces the loss of damping and the risk of device heating.Since the range of proportion gain values which make the system stable is larger,the proportion gain value is increased prop-erly to improve steady-state accuracy and dynamic response speed of the system.The simulation result ver-ifies the correctness and effectiveness of the proposed selection method of feedback currents.%通过理论分析提出带LCL滤波的无源阻尼并联型有源电力滤波器(SAPF)双环控制系统电流控制点的选取方法.与传统的内外环反馈电流均取自电网侧相比,当内环反馈电流取自逆变器侧,外环反馈电流取自电网侧时,使系统稳定的阻尼电阻和比例增益取值范围较大,稳态精确度在高次谐波处略有降低,由于一般高次谐波含量较少,这种降低几乎可以忽略不计.因此,只需要较小的阻尼电阻,就可使系统达到稳定以及获得很好的稳态精确度,这样可以减小阻尼损耗,以及减小设备发热隐患;由于使系统达到稳定的比例增益值取值范围较大,可以通过适当增大比例增益的方式来提高系统的稳态精度,同时加快系统的响应速度.仿真结果验证了所提控制系统反馈电流选取方法的正确性和有效性.