The Design And Simulation Of Three-level Inverter

Because of the superiority such as higher power quality, lower harmonic components, better electromagnetic compatibility, and lower switching losses in its output, three-level inverter is applied widely in high-voltage and high-power applications. PWM control technology could gain excellent sine wave output by altering on and off sequence and duration in inverter’s switching device in reasonable way. By far, PWM control takes a leading role in three level.This article firstly briefly introduces the research background of multi-level inverter, the significance and research progress. Three-level inverter three basic topological structure of the working principle and characteristics of understanding, analysis to select the diode clamp structure as the design of the main circuit, and to build up the mathematical model of this topology.Then based on the control DOF combination of ideas, several existing carrier PWM method, a new carrier on the basis of the RP-overlap-Switching frequency optimal PWM method, and proved by the simulation, the methodeffectively improve the utilization of DC voltage.Then the paper focuses on the three-level inverter common midpoint potential imbalance, from its formation mechanism start to the neutral current as a breakthrough, leads to the accurate calculation of the zero-sequence voltage and zero-sequence voltage that freedom.injected into the improved PWM method, and on this basis by adding Test-Restrict-Verify-Revise " real-time control algorithms.At last this paper establishes three level inverter control model based on MATLAB software. The simulation results show the researched PWM algorithm is feasible and effective. It also has the advantage of carrying out in simple and intuitive way.