Research On Control Technology Of Single-phase Inverter Based On DSP

The rapid development of new energy grid-connected inverter control technology promotes the development of power electronic technology.A number of power electronic devices are connected to the grid,which seriously challenges the stability of the power system.Since power electronic devices affect the performance of the power system,it is of great significance to design power electronic control strategies for this effect.In order to solve this problem,this thesis proposes a switching sequence control method.Different from PWM(Pulse Width Modulation)and MPC(Model Predictive Control),this method rigorously analyzes the stability of the power system in theory and steady-state accuracy.This article initially tries to apply it to the single-phase Ltype inverter system,that is,to study the switching sequence control of the first-order system.The contributions of this dissertation are as follows.1)In view of the influence of power electronic components on the power system,this thesis transforms the switching control problem of power electronic components into a switching sequence control problem,and uses mathematical methods to describe the switching sequence control problem in detail,which mainly includes selecting the time switching sequence and the switching subsystem sequence.We can realize the tracking of the given current according to the output current on the inverter side by selecting the time switching sequence and the switching subsystem sequence2)For the first-order continuous system,a continuous switching sequence control method is proposed.By designing a continuous fixed frequency switching sequence controller and a continuous variable frequency switching sequence controller,the inverter side output current can track the given current quickly and stably.Compared with the traditional inverter current control method,this method has a systematic theoretical analysis and can accurately calculate the steady-state accuracy of the switching system,and researchers can choose appropriate system parameters to improve tracking accuracy.3)In order to realize the digital control of the switching system,the continuous model of the first-order system is discretized,and the discrete switching sequence control method for the first-order open-loop and closed-loop systems are proposed.In the firstorder open-loop and closed-loop systems,discrete fixed-frequency switching sequence controllers and discrete variable-frequency switching sequence controllers are designed to achieve fast and stable tracking of the given current according to the output current on the inverter side.Compared with the traditional inverter current control method,this method has a detailed theoretical basis,which can obtain precise tracking accuracy and improve the performance of the system by selecting appropriate system parameters.This text verifies the effectiveness of the switch sequence controller through simulation,and it verifies its feasibility through DSP experiments.The switch control method proposed in this thesis can not only effectively analyze the performance of the switch system,but also improve the tracking accuracy.It provides new research ideas for the field of grid inverter current control technology,and it is significancant for power electronic system modulation technology.