Research Of The Inverter Harmonic Suppression And Filetr Design Based On Variable Frequency Modulation Algorithm

In today’s society of energy supply and the contradiction between human demand has become the key factors that hinder the development of science and technology, at the same time because of traditional human energy the atmosphere and environment pollution caused by worsening human survival environment. On this basis, the replacement of traditional energy in recent years, as a new energy got fast development, the solar energy is the typical representative among them. With PWM inverter is becoming more and more widely used today, the harmonics generated by power electronic devices has become the largest interference sources, and PWM inverter harmonic content in output waveform is higher. High harmonic content, the filter design and power quality is critical to power quality of current the grid-connected inverter.Therefore, research higher harmonics suppress and filter design make sense. Accordingly this paper introduces a new variant carrier frequency modulation algorithm.While the off and on time of the switch does not increase, the number of high-order harmonic content of the modulation of the output voltage is less compared with the fixed carrier frequency modulation. Then on this basis, we designed LCL filter that meet the requirements of the grid with a smaller total inductance. This kind of filter design approach is different from the traditional filter design, it is based on the carrier frequency of the harmonic spectrum modulation algorithm under varying distributions, and then based on the relationship between the resonance frequency harmonic spectrum, obtained resonant frequency and LCL filter correlation filter parameters. Finally, the simulation analysis and prototype testing to verify the higher harmonics of the modulation algorithm effectively reduced under the LCL filter and the actual performance of the design is more superior.