Research of Improved Iterative DFT Method in Harmonic Current Detection

The harmonic detection of active power filter is a very crucial part. This paper proposed a fast harmonic detection method based on improved iterative DFT. The main features of this method are that 1) the computational complexity of iterative DFT is much lower than that of DFT, 2) it can be used to detect only specific harmonic components, 3) the harmonic current can be directly obtained without low-pass filter, phase-locked loop, inverse transform. These characteristics make this improved iterative DFT method especially compatible with active power filter. This method was simulated with MATLAB, and the feasibility of its application was verified experimentally.