Single-phase High-frequency Grid Inverter Control Technology Research

Since energy shortage and environmental pollution become a big problem, theutilization of renewable energy has aroused huge interest. The grid-connected inverteris the key energy processing unit in the renewable energy generation systems.Technical difficulties in the design of grid inverter is how to design the control link.Inorder to achieve the output terminal of alternating current with the grid voltage of thesame frequency and the same phase of the sinusoidal signal. Based on single-phasehigh-frequency inverter system, the dissertation focused on the key technologyresearch, and provides the necessary theoretical warrants and a basic realizableapproach for design and development of the system.1. The inverter system’s application field and development trend have beenresearched. The theory and technique foundation have been deeply researched basedon the system’s current control and pulse width modulation. The paper explained theresearch background of the project and the project tasks undertaken by author.2. The single-phase high-frequency inverter can be divided into high frequencyinverter, cycloconverter and output filtering. According to the given topography of thevoltage inverter, its mathematical model is studied. Analyze and design the LC filterparameters particularly using the equivalent model.3. In order to solve the problem of the poor performance and load adaptability ofinverter being not strong, this paper researched three kinds of practical inverter currentcontrol method. Through algorithm theoretical derivation and analysis, and combinedwith the mathematical model，three kinds of current control method was improved. Thecorresponding simulation results were given. Results showed that the improved PIDand PR mixed double closed-loop current control method, performed high accuracy,robust and strong load adaptability.4. In order to realize the current control technology, this paper studied the highfrequcency grid inverter pulse width modulation technology. Research was mainlyfocused on the specific Harmonic eliminating pulse width modulation (SHEPWM) method. The SHEPWM modulation model of the high frequcency grid inverter waspresented in this thesis. The correctness of the modulation model was verified bysimulation.5. Finally, the experimental platform for the high frequency grid inverter was setup. Based on SHEPWM modulation of mixed double closed-loop current controllingmethod was realized in the DSP. Results showed that experimental values werebasically in agreement with standard ones, the mathematical model and controlstrategy were correct and feasible.