The harmonic suppression characteristic analysis of phase-shifting reactor in rectifying system

Multiple rectifier technology is an effective method to reduce the harmonic current injected from converter to the grid [1], and phase-shifting reactor (PSR) is a kind of magnetic equipment which can be used to realize the function of phase-shifting[2]-[4]. In the multiphase rectifying system, the phase-shifting property of PSR plays an important role in harmonic suppression, meanwhile, as an inductive device, its filtering property cannot be neglected. Therefore, with the purpose of evaluating the phase-shifting and filtering properties of PSR in the harmonic current suppression, three kinds of reactors with approximate harmonic suppression effect in the 6-phase rectifying system are designed, one is without phase-shifting, and the other two are with phase-shifting in different phase-shifting angle. And then, based on the Fast Fourier Transform (FFT) algorithm and the frequency sweep method, the phase-shifting and filtering properties are respectively revealed by the harmonic current spectrum diagram and the amplitude-frequency characteristic curve. Lastly, the idea to introduce the low-pass filter´s design method to the design of PSR to strengthen the harmonic suppression effect is proposed.