Research On The Control Strategies Of Main Circuit Of Current Fed Z-source Inverter

This dissertation firstly describes the situation of the development of inverter at home and abroad. Analyzes the shortcomings and limitations of the traditional inverter, and then analyze a new type Z-source inverter. It can overcome the deficiencies of the traditional inverter and has the new features that the traditional inverter not have.The second chapter of the disertation analyzes the mathematical modeling of the current-fed Z-source inverter. First of all, it builds the mathematical modeling of three-phase coordinate system of the Z-source inverter, and then turn it into two-phase stationary coordinate system, last turn it into two-phase rotating coordinate system, So we have the theoretical basis for after application.The third chapter of the disertation analyzes the working principle of the current-fed Z-source inverter, including the main circuit topology, the buck-boost mechanism, and the design of main circuit.The fourth chapter of the disertation describes the control strategy of the the current-fed Z-source inverter. Traditional control method does not apply to new type Z-source inverter, so a three-valued logic control strategy is proposed. After conversion, we can turn the traditional control strategy to the three-valued logic control strategy, after that, We analyzed the PWM control strategy, include the method of the third harmonic injection, the SVPWM control strategy and so on.In the fifth chapter of the disertation we made a simulation of the inverter using the simulink of MATLAB, firstly we built the two-three logic switching model, so we can convert the two-valued logic control strategy to the three-valued logic control strategy. Then we applied the third harmonic injection method and the SVPWM control strategy and so on. At last, we analyzed the current and voltage waveforms of the current-fed Z-source inverter. And verify the effectiveness of the strategy.Finally, we have the summary and outlook of the research and application of the current-fed Z-source inverter, and points out the work to be carried out after.