Research on harmonic suppression method of SPWM inverter circuit for photovoltaic power generation system

To effectively reduce and suppress the harmonics generated by single-phase inverter circuits, this paper mainly investigates the harmonic characteristics of single-phase Sinusoidal Pulse Width Modulation (SPWM) inverter in the output voltage and its suppression methods. According to the SPWM principle and Fourier series theory, the mathematical model and simulation of the output voltage of the SPWM inverter are established, and the harmonic characteristics of the SPWM inverter are analyzed. Secondly, the harmonic content and distribution of the output voltage under three different carrier control methods are investigated. Then, two effective methods for suppressing the harmonics of the output voltage of single-phase SPWM inverters are investigated: selecting the appropriate carrier ratio and injecting the proper number of harmonics. Finally, the study shows that a single-phase unipolar frequency doubling SPWM inverter can effectively filter out the high harmonics, making the output voltage waveform smoother and closer to the sinusoidal waveform. This study will have a certain positive impact on the future development of energy-saving power supply, high-quality power supply, and high-performance power supply technology in China, which can realize the efficient and low-pollution use of electric energy.