Research On Specific Harmonic Elimination Technology Based On Chaotic Particle Swarm Optimization

With the rapid development of high power semiconductors,especially insulated gate bipolar transistors(IGBTs)and integrated gate Commutation Thyristor(IGCTs),medium voltage high power transmission equipment is increasingly used in the chemical industry,mining and steel industry....Gold smelting industry as a technology and transportation.This device saves energy,increases productivity and improves quality.Furthermore,the problem of harmonics it creates cannot be ignored,so eliminating these harmonics has become an important part of inverter research.SHEPWM technology has the advantages of low frequency switching power supplies and superior signal quality and is widely used in medium and high voltage and high bandwidth applications.In this article,we mainly study 2-tier and multi-tier inverters,and also thoroughly study SHEPWM technology.Firstly,the basic topology and control mode of common multilevel inverter are described,and the basic characteristics of multilevel inverter are analyzed.Taking two-level inverter and seven level inverter as examples,this paper systematically expounds the working mechanism of SHEPWM,constructs and calculates the two-level SHEPWM equations,carries out simulation verification,and eliminates the required harmonics.It also analyzes the defects of existing operation methods,such as numerical algorithm and genetic al gorithm,in the process of calculating SHEPWM equations.The primary problem of SHEPWM modulation is the solution of its nonlinear transcendental ordinary differential equations.To solve this problem,numerical solutions such as Newton iteration method,homotopy algorithm and Walsh function method were firstly produced.However,since the traditional single numerical solution is highly dependent on initial values,people advocate using intelligent optimization algorithm to solve SHEPWM nonlinear differential equations.Although the intelligent optimization algorithm does not depend on the initial value,It usually has the problem of slow convergence speed and low accuracy.Therefore,this paper presents a solution of SHEPWM nonlinear equations using logistic model optimization particle swarm optimization(CPSO)in chaos theory.This method combines the swarm search method of particle swarm optimization algorithm and the advantages of chaos algorithm in perturbation and local optimization,which greatly improves the search range and accuracy of the algorithm.In order to verify the effectiveness of the proposed algorithm,a simulation experiment is carried out to solve the SHEPWM equations.Next,we will conduct several simulation experiments with SHEPWM technology,based on an optimization algorithm for a chaotic swarm of particles.The experimental results show that the accuracy and the probability of convergence of the optimization algorithm for a chaotic swarm of particles are high and the computation is premature.To test the switching angles of the optimization algorithm for a chaotic swarm of particles,a two-tier inverter experimental platform was built.The results show that the switching angle solved by the chaotic swarm optimization algorithm is valid.