并联型有源电力滤波器的电流跟踪控制实现方法

Current tracking control implementation method for shunt active power filter

在传统的无差拍电流跟踪控制基础上,提出了一种改进的无差拍电流跟踪控制方法.该法首先采用线性预测方法,在当前时刻预测出有源电力滤波器在下一时刻的输出电流参考值,然后用有源电力滤波器的离散化电流跟踪控制数学模型计算出脉冲宽度调制信号的占空比.这样就弥补了传统的无差拍控制方法因算法复杂导致计算延时的不足.同时,在有源电力滤波器系统投入逆变运行前,采用直流侧电容预充电和使直流侧电压线性增加的方法,防止启动时产生直流侧冲击电流;采用直流侧电压比例-积分控制方法,使得系统在逆变过程中,直流侧电压大小只在一定范围内波动.而且,此控制策略在基于数字信号处理器TMS320LF2407A的硬件平台上得以实现,并对有源电力滤波器在投入运行前后的系统网侧电流波形进行了实验分析.实验结果表明,所提的电流跟踪控制和直流侧电压控制方法可以使有源电力滤波器有效滤除电网中的谐波电流.

An improved deadbeat current tracking control method was proposed based on the shunt active power filter. First, the output reference current value of the next time was predicted using the linear prediction method at a certain time. Then, the duty cycle of pulse width modulation signal was calculated based on the discrete mathematical model of the active power filter. This method can not only eliminate the calculation delay due to the algorithm complexity effectively but also ensure the stability of the system. At the same time, the direct-current link （DC-link）impact current was inhibited using the method of DC-link capacitor pre-charging and DC-link voltage increased linearly before the active power filter was put into operation. Proportional integral control method was used to make the DC-link voltage fluctuated within a certain range. Furthermore, the presented control strategy was implemented on the hardware platform of the active power filter based on the digital signal processor TMS320LF2407A. Power grid side current waveforms were analyzed before and after the active power filter was put into operation. Experimental results show that the proposed current tracking control and DC-link voltage methods can make the active power filter to eliminate the harmonic currents effectively in the power grid.