Study On SPWPM-Mode-Controlled High-Frequency Link Inverter

Recently, with the rapid development of power electronics, more and more attention and research work has been paid to the high-frequency link (HFL) inverter. Obviously, it has huge advantages in the application situations of realizing high efficiency, high power density and small in size and light in weight. The research work of the paper is carried out based on this key guiding idea.First of all, with an overview of the application feilds of inverters, the paper classifies inverters into two categories: low-frequency link and high-frequency link. During the dissertation of development of the HFL inverter, the advantages and disadvantages of several typical voltage mode and current mode are discussed in detail, and the proposed topology and existing control strategies of bi-directional voltage mode HFL inverter up to now, are discussed and analyzed as the key points.Secondly, based on the analysis above, taking the full-bridge and full-bridge mode two-stage (DC/AC/AC) power conversion topology as an example, discusses and analyzes the basic principles of main circuit: the twelve kinds of circuit mode within one high frequency switching period are carefully analyzed and the steady-state output characteristic curves are given. After the dissertation and analysis of uni-polarity phase-shifted control sinusoidal pulse width phase modulation (SPWPM), introduces the soft-switching principle of phase-shifted full bridge in a brief way.Then, based on the principles of main circuit, a comprehensive analysis of uni-polarity phase-shifted SPWPM mode high-frequency linkage principle is carried out. After establishing the mathematic mode of the DC/AC converter pre-stage and the last cycloconverter stage respectively, analyzes and explains the HFL principles using mathematic methods. At last, the simulation results based on Matlab and PSIM validates the feasibility and validity of theoretic analysis process.Thirdly, this paper emphasizes the design and implementation process of full-bridge bi-directional HFL inverter. As the key component of hardware circuit, the high-frequency transformer's design process is introduced carefully. Meanwhile, the design and the realization process of software system based on DSP (digital signal processor) are described in detail. After debugging and testing the system, the experimental results are given and analyzed detailedly. The results indicated: the control theory of uni-polarity phase-shifted SPWPM mode high frequency linkage is absolutely right and feasibility; the output performance of the power supply is good. So it will be a good developing direction for HFL inverters. Finally, the HFL inverter is combined with the dual-loop control method based on voltage and current feedback. The dual-loop control method has two typical control schemes, including the inductance current inner loop feedback and the capacitance current inner loop feedback. After analyzing and designing the two control schemes, two different simulation models are established. At last, compares and analyzes the respective characteristics of the two strategies through simulation. The simulation results indicated: this kind of inverter based on the combination of the HFL and the dual-loop control method, has high electric performance. In the occasion of realizing high performance, high efficiency and high power density, it will have extensive application prospect and research value.