有源滤波过采样数字滞环电流跟踪控制方法

Control Method for APF Hysteresis-band Current Tracking Based on Digital Over-sampling

以改善谐波补偿精度和稳定开关频率为目标,提出一种有源电力滤波器(APF)滞环电流跟踪控制的过采样数字实现方法。该方法利用数字芯片过采样下抽取因子的不同,满足各个控制运算模块对动态响应的不同需求;充分配合利用数字信号处理器(DSP)的2种运算方式———采样中断运算和主循环运算,保证补偿量检测的实时性和补偿电流的同步性;对同一指令量进行N次滞环跟踪,功率开关器件的状态切换只依赖于上一开关周期参数,在稳定开关频率的前提下,具有高精度电流跟踪控制能力。与传统滞环实现方法相比较,所提出的过采样数字实现方法,既克服了开关频率不固定的缺陷,也提高了谐波补偿精度,具有很好的实用性和可靠性。通过搭建65kVA三相三线APF工业样机,分析和验证了所提方法的有效性。

An implementation method for hysteresis-band current tracking for active power filter （APF） based on digital over sampling is proposed, which enables precise compensation of harmonic current and stabilizes the switching-frequency. This method can meet different dynamic response demands of control and operation modules by utilizing different extraction factors of digital chip over-sampling. And it fully coordinates two kinds of operations in the digital signal processor （DSP）, the sampling interrupt operation and main loop operation, which ensures real-time harmonic current detection and synchronous tracking for the compensating current. The same reference will be tracked N times and the change of power switching device status depends only on the parameters of the preceding switching-period, resulting in high precision tracking for current. Compared with the traditional hysteresis-band current control method, the proposed method has the advantage of not only stabilized switching-frequency but precise harmonic compensation as well, proving its applicability and reliability. A 65 kVA experiment system for three phase three-wire APF is built for verification and the validity of the proposed method is confirmed by experimental results.