Research On Inverter Harmonic Optimization Based On Improved Particle Swarm Optimization

Since the start of twenty-first Century, related technologies in the field of power electronics, microelectronics and industrial control continue to break through. PWM modulation technology has been more and more widely used in a variety of power electronic inverter device.With the development of nonlinear devices, harmonic hazards are more and more serious. The inverter is a kind of harmonic source. This paper deeply studies the application of the Newton iterative method, genetic algorithm, especially the particle swarm optimization algorithm in specific harmonic elimination technology.Although SPWM, SVPWM and other traditional control methods have been widely used in inverter, there is still limits to low DC voltage utilization and large power consumption. This paper breaks the traditional PWM control mode to study the specific harmonic elimination pulse width modulation technology based on the improved particle swarm optimization algorithm.First of all, this paper describes the research background of the topic, introduces the current situation of harmonic suppression technology, analyzes the causes of the inverter output harmonic and the possible harm, and expounds the significance of this research.Then, the classical Single phase inverter circuit structure and several common control techniques are analyzed and studied. This paper mainly introduces the control methods of SPWM, SVPWM and random PWM, and compares their advantages and disadvantages and application environment, and then leads to the SHEPWM control technology of this paper study.It has a brief overview of SHEPWM technology. The phase voltage mathematical model of the voltage type inverter output is established based on Fourier series expansion of periodic signal. The Fourier series expansion of phase voltage is an effective basis to analyze the distribution law of harmonic and to establish the SHEPWM equation group.SHEPWM equations are nonlinear transcendental equations, which relate to the relationship between the fundamental and harmonic wave of the inverter output voltage and switching angle.Solving the equations is the solution of switching angle.the solving prthe Newton iterative method depends on the initial value of the selection.Although the genetic algorithm is not strictly dependent on the selection of initial value, the algorithm is also easy to fall into local optimum.More and more swarm intelligence algorithms are applied to the solution of SHEPWM equations. Particle swarm optimization algorithm is a kind of intelligent algorithm. It is simple and easy to understand. The process does not depend on the initial value of the selection. Through the reasonable improvement of the inertia weight and the shrinkage factor of the particle swarm algorithm, the premature convergence of the SHEPWM nonlinear transcendental equations is avoided.According to Newton iterative method, genetic algorithm and improved particle swarm optimization algorithm, the MATLAB is applied to calculate and compare the 5 switching angles SHEPWM equations in the 1/4 period. The results show that the improved particle swarm optimization algorithm has more advantages in the comparison of the parameters of the iterative times and harmonic distortion. The effectiveness of the improved particle swarm optimization algorithm for harmonic wave optimization is verified. Finally, based on MATLAB/Simulink, the simulation platform of single phase inverter is established, and the data obtained by the improved particle swarm optimization algorithm is used in the experiment. The results show that the algorithm is feasible.