并联型有源电力滤波器输出滤波器的阻尼控制

为了减少电感的使用量,针对三阶电感-电容-电感(LCL)系统容易出现谐振的问题,提出了基于电容电流反馈的有源阻尼控制策略.首先建立了有源滤波器输出LCL滤波的数学模型,推导了LCL系统在高次谐波下的传递函数,由根轨迹图分析出电容电流反馈系数的取值范围,结合系统的幅值裕度,从中优化得到合适的闭环参数,最后在MATLAB中建立了电力系统模型.仿真结果表明:采用电容电流反馈的有源阻尼控制策略得到电流的总谐波失真含量是3.72%,优于采用阻尼电阻控制策略的4.21%.该策略可以很好地对系统的谐波进行补偿,开关频率处纹波衰减率较为理想,系统的稳态和动态性能均满足求.

Damping control of filter based on shunt active power filter

To reduce the amount of inductance,a damping control strategy was proposed aimed at thirdorder resonance problems.Firstly,the mathematical model of active power filter was established,and the transfer function of LCL system was derived in the high-order harmonics.The value range of capacitor current feedback coefficient was obtained from the root locus,and the appropriate close-loop parameters were obtained combined with the system amplitude margin.Finally,power system model was established in MATLAB.The simulation results show that the content of total harmonic distortion of current is 3.72 ％ using the control strategy of capacitor current feedback,which is 4.21％ higher than that using the control strategy of damping resistor.The strategy proved to be a good system to compensate harmonics,and ripple rejection in switching frequency is good.Both steady-state and dynamic performance of the system can meet the requirements.