Harmonic Analysis and Cancellation of Inverter Systems with Linear Phase‐Shifting Transformer

Abstract

In order to improve the electrical performance of the inverter system and make its output waveform close to a sinusoidal waveform, an inverter based on a linear phase‐shifting transformer is proposed, which can eliminate the low harmonics with opposite phase by the effect of phase shift and superposition. Firstly, the components and working process of the multiple superposition inverter system are introduced, and the working principle and winding structure of the linear phase‐shifting transformer are analyzed; Secondly, the Fourier decomposition of the inverter output voltage is carried out to obtain the harmonic currents at the same frequency as it, and it is demonstrated that the inverter is capable of eliminating most of the harmonics below the 23rd order by calculating the magneto‐dynamic potential synthesized in the air gap; Again, in order to overcome the harmonic electric potential caused by the edge‐end effect and the tooth slot structure of the linear phase‐shifting transformer, the secondary side winding of the linear phase‐shifting transformer adopts a short pitch structure, and it is proved that this structure has a significant suppression effect on the 5th and 7th harmonics without reducing the fundamental wave amplitude; Then, the model of multiple superposition inverter system is built based on Maxwell simulation software, and the effectiveness of the inverter device and winding structure on harmonic suppression is proved through spectral analysis of voltage waveforms with different load types and power factors; Finally, its reasonableness and accuracy are verified by experiments. © 2023 Institute of Electrical Engineer of Japan and Wiley Periodicals LLC.