Asymmetric selective harmonic elimination technique using partial derivative for cascaded modular active rectifiers tied to a power grid with voltage harmonics

Abstract

This paper proposes a real time selective harmonic elimination technique for the current of the active rectifier. The partial derivation technique is applied to the Fourier series equations of voltage waveforms to implement real time SHE technique. In order to control the magnitude and phase of the low order current harmonics of the active rectifier, a new controller is proposed to fully mitigate the 5th and 7th current harmonic orders of the active rectifier even with the influence of grid voltage harmonics. Moreover, in this paper, an asymmetric voltage waveform will be employed to control both the magnitude and phase of the current harmonics of the active rectifier. The proposed technique needs very low memory storage for look-up tables, so it saves a lot of resources for DSP. Finally, the proposed technique is verified by MATLAB/Simulink simulations and experiments. The technique can be extended to eliminate more orders of harmonics.