Adaptive learning algorithm assisted current control for active filters

An active filter (AF) is required to have a high current control capability of tracking a time-varying current reference. However, a steady-state current error always exists because the current reference varies in time. This paper proposes the application of adaptive digital signal processing (ADSP) to the current control of AF. ADSP does not require any additional hardware, but it can automatically minimize the steady-state error. Since the processing time available by a computer is limited, ADSP cannot eliminate higher order harmonics but can eliminate lower order harmonics such as 3/sup rd/ to 17/sup th/. Experimental results demonstrate that ADSP is useful for improving filtering performance.