The Design And Implement Of Harmonic Suppression Inverter Based On The Frequency Dividing Droop Control

With the increasing installation capacity of distributed generation, the harmonic content of the power system is on the rise when the distributed power which as a harmonic source connecting to the grid. What is worse, the widely use of nonlinear loads makes the harmonic pollution problem of the power system more seriously. By taking the grid-connected inverter which was based on voltage-controlled mode as research object, and choosing harmonic suppression as research purpose, this paper finally introduces the strategy of frequency dividing droop control. This strategy makes the inverter have the ability of suppressing particular harmonic when the inverter is transferring power, which will improve the adaptability of the power system for nonlinear loads.This paper studies the principle of using the inverter to suppress particular harmonic, and develop the prototype. Specific work is as follows:1. It introduces harmonic and the research status of suppressing harmonic at home and abroad. Finally this part put forward the strategy of frequency dividing droop control according the situation that the number of nonlinear loads in the power system is rapidly increasing.2. It introduces several traditional control strategies of the grid-connected inverter, among these control strategies, droop control is focused on.3. It emphasizes the importance of the method of detecting harmonic, and then introduces two common methods of detecting harmonic, compares them and chooses one as the harmonic detection method of this paper.4. It introduces the design of frequency dividing droop controller: the strategy of the fundamental part is robust control which is evolved from the traditional droop control, and the strategy of the harmonic part is the frequency dividing droop control which is acquired through building the mathematical model to analyze the principle of suppressing harmonic. Finally, this part uses PSCAD to run the simulations and verifies the validity of the frequency dividing droop control strategy from the results of simulations.5. It introduces the design of the prototype. The heavy-current part of the prototype includes the chosen of the power devices and its driver, the weak-current part of the prototype includes the DSP minimum system and its peripheral extended circuit, the signal processing circuit.6. It conducts the experiments, and verifies the strategy of frequency dividing droop control from the results of experiments.