Analysis And Control Of Residual Harmonics In Specific Harmonic Elimination Technology

At present,the application of power electronic devices is more and more extensive,and high-power switching devices are used in many important work situations.Frequent switching of high-power switching devices generates a large amount of harmonics in electrical equipment,and also increases Unnecessary energy loss.Therefore,in order to improve the utilization efficiency of electric energy,it is necessary to deal with the harmonics generated by the high-power switching device,and the specific harmonic elimination technology is one of the better ways to eliminate the harmonic effect at present,and the method can effectively suppress the specified subharmonic,Therefore,the application of specific harmonic elimination technology to high-power switching devices can improve the utilization efficiency of electric energy and produce high-quality sine waves.Due to the actual operating conditions,there must be residual harmonics in addition to the harmonics that have been eliminated.Therefore,it is necessary to analyze the distribution law of residual harmonics and study the way to control the residual harmonic distribution and amplitude.Firstly,a specific harmonic elimination technique is established for the mathematical model of the output voltage Fourier decomposition applied to the unipolar and bipolar three-phase inverter circuits,and the Newton iterative method is used to solve the nonlinear transcendental equations.If the undesired solution of the initial value selection has the possibility of divergence,it is only suitable for solving the switching angle in the offline state.This paper proposes to apply the particle swarm optimization algorithm to a specific harmonic elimination technique.When solving this algorithm,it is not necessary to assign a specific initial value and the convergence speed is faster.Secondly,the bipolar three-phase inverter circuit is used as the simulation model.The particle swarm optimization algorithm is used to solve the solution of the nonlinear transcendental equations,and the simulated annealing algorithm is introduced into the particle swarm optimization algorithm to improve the premature and local search of the original algorithm.Excellent defect.The optimized algorithm is combined with the Newton iteration method,namely Newton iteration-simulated annealing to optimize the particle swarm optimization algorithm to find the solution that satisfies the precision.Under this algorithm,the total harmonic distortion rate of the output voltage and current is lower,and the suppression effect of the harmonics to be eliminated is also better.Then,compare the SPWM technology with the ability of specific harmonic elimination techniques for harmonic suppression.The spectrum analysis of the SPWM and the specific harmonic output current is compared in a simulation model in which the remaining modules and parameters are identical except for the signal generation module.Under the control of specific harmonic elimination technology,the effects of load properties and resistance values in the load on the output current are analyzed.Finally,the distribution law of residual harmonics in the output voltage of the bipolar three-phase inverter circuit under the control of SPWM technology and specific harmonic elimination technology is summarized.It is verified by simulation experiments that changing the carrier ratio in SPWM technology and changing the number of switching angles(below a certain number of switching angles)in a specific harmonic elimination technique can control the distribution of residual harmonics,and increase the modulation degree in these two techniques.Both can reduce the value of the total harmonic distortion rate.