Research On Control Strategy Of Single-Phase High-Frequency Link Inverter

In recent years,with the rapid development of science and technology,different walks of life have put forward higher and higher requirements for the performance of DC/AC inverters.DC/AC inverter devices are generally required to have the characteristics of small size,light weight,high power density,and fast in dynamic response in the fields of new energy power generation,aerospace,communications,transportation,etc.Due to the traditional isolated DC/AC inverter use the power frequency transformer isolation technology,the above requirements cannot be met,so the high-frequency link inverter with good performance stands out.The research value is quite considerable and has been favored by scientists.Firstly,the research is based on single phase high-frequency link inverter.By comparing and analyzing the characteristics and applications of various topologies,the full bridge-bridge high-frequency link inverter topology is chosen.Secondly,it introduces several commonly used control strategies,summarizes the advantages and disadvantages of each control strategy and studies an improved sinusoidal pulse width and position modulation strategy(SPWPM)based on full bridge-bridge circuit topology.The equivalent circuit and working principle of the high-frequency link inverter at different times under this strategy are analyzed in detail.This control strategy can not only effectively reduce the number of times of switching of the circuit,reduce the switching loss of the inverter but also solve the problem of safe commutation of the post-stage cycloconverter and improve the reliability of the system.At the end of the chapter,the effectiveness of the proposed control strategy is verified by PSIM simulation.Then,the paper builds the model of the pre-stage full bridge inverter and the post-stage cycloconverter.The feasibility of the control strategy is proved by mathematical derivation and use the PSIM simulation software to verify the theoretical derivation.After that,the high-frequency link inverter closed-loop control method was explored.Through the analysis and comparison of the performance of the PI regulator and the PR regulator,the closed-loop control of the voltage and current double closed-loop control system with the classical quasi-PR regulator as the core is selected and the simulation of the load step is carried out.The results show that the designed closed-loop system has good static response and dynamic response.Finally,a full bridge-bridge high-frequency link inverter experimental prototype with input DC voltage of 410V,output AC voltage of 220V/50Hz and rated power of 1kW was built.The experimental results show the correctness of this improved control strategy.