Research On Back - To - Back Voltage Source Converter

Concern of the energy-saving, environmental protection and new energy development in today’s world, the back-to-back converter system has been widely used in many fields, such as widely used in the field of HVDC systems, wind power, and the motor frequency control, etc. The back-to-back voltage source type variable flow system has become the core technology of the field. Therefore, in-depth study of the back-to-back voltage source converter system in theory and practice have great significance.In paper, the back-voltage source converter is mainly researched by analyzing the converter topology, control strategy, the device parameters, hardware design, software design, software simulation, testing and commissioning aspects.Firstly, according to the research background and significance of this topic, through analysis the back-to-back voltage source converter development status and control strategy research status, to analysis and research the significance and the prospect of development in this topic.Secondly, this part simply introduces the classification of PWM converter and two different topological structures, then the working principle of back-to-back voltage source converter and power flow control are analyzed in detail. In the analysis the mathematical model of back-to-back VSC converter system is established on the basis of its working principle, and analysis two different control strategies used in the system.Again, this paper introduces the design of hardware circuit of back-to-back VSC converter system in this dissertation, and through the software to simulate and verify it. Among them, firstly simple introduction the control system of the core, DSP TMS320F28335 chip model; secondly, circuit various components especially parameter calculation and selection of inductance and capacitance; finally, through the MATLAB software on the of simulation to verify feasibility of the principle experiment.Then, the thesis introduces the software design principle and design steps of back-to-back VSC converter system in this project. The software design of the whole system mainly consists of three parts:the main program design, main interrupt program design and protection program design, and in the three part of the design principles and processes are introduced, which in the main interrupt program design part of the software phase-locked loop design and digital PID design to do a detailed introduction and analysis.Finally, according to the experimental requirements, the hardware circuit board welding, then experimental platform were completed, and the experiment was carried out. Modular debugging of the variable flow system. First, the experiment is carried out on one side converter, then the inverter rectifier is separated from the experiment, finally the system experiment is carried out. The experiment shows that the output waveform is good, which meets the final design requirements. In addition,this paper briefly introduces the problems and defects in the research of this subject, and the problems to be solved.