Research On Multi-level Inverter Harmonic Suppression Based On The PSO Algorithm

Multi-level inverter has been widely used, because it’s great output capacity, high output voltage and small current harmonic. In the case of the switch under the same voltage, multi-level inverter can achieve a higher voltage of the inverter. In order to reduce the switching losses and improve the efficiency of the inverter, the switching frequency of high-power electronic switching device is generally limited to about1kHz. In recent years a variety of harmonic suppression methods can eliminate a certain number of harmonics, but may cause other number of the harmonic content increases or other issues. In order to solve the problem of the high power multi-level PWM inverter with large output high harmonic content, this paper uses the harmonic suppression method based on the PSO algorithm, the results of the simulation prove the effectiveness of the algorithm.First, this article analyzes the multi-level inverter topology and its working principle, and the harmonic of typical multi-level inverter topology output voltage waveform, which provides a theoretical basis for later simulation analysis. Second, this paper determines the evaluation function, which the target is the total harmonic distortion rate of the output voltage and current, and builts the three-level and five-level inverter models in Matlab/Simulink based on the PSO algorithm. The harmonic suppression method bansed on the PSO algorithm, can redunce the harmonic content of the multi-level inveter output voltage and current greatly.As to the narrow pulse width problem in the high power low frequency multi-level inverter system, in order to reduce the switching losses of switching devices and the output harmonic content, this paper uses a narrow pulse suppression strategy firstly based on the PSO algorithm resolved the narrow pulse problem in the multi-level inverter successfully on the basis of not increasing the total harmonic content.