Energy-shaping Control For Z-source Inverter In Photovoltage Power Generation

Solar energy power generation as a kind of new energy has a big advantage. It hasthe advantages of no noise, easier miniaturization installation, suitable residentialinstallation. So it gets a fast development. The research is mainly about the new controlstrategy of Z-source inverter which is applicable to the solar power. Through theanalysis of the current situation of the development of Z-source inverter, the deficiencyof the current Z-source inverter is found. Through the analysis of the advantages of theenergy-shaping control and combined with the characteristics of photovoltaic powergeneration, using energy-shaping control strategy is proposed for Z-source invertercontrol research.First of all, the theoretical basis of Z-source inverter is explained. Then the threevoltage boost modulation mode is analyzed in detail and it tells how to insert theshort-through time into the inverter with SVPWM modulation strategy.Secondly, the traditional PI control of Z-source inverter is studied. Based on thegrid current closed-loop control strategy, control characteristics of the grid control areanalyzed. By adjusting the parameters of the PI, the system is made to meet theexpected control goal; and then the off-grid characteristic of Z-source inverter isanalyzed based on the output voltage closed loop control. In the grid and off-grid switch,the modulation signal control and given current increasing control are proposed toreduce the switch impact. The deficiencies of PI control are summarized, which laid afoundation for the propose of energy-shaping control strategy.Thirdly, through the analysis of the theoretical basis of energy-shaping controlstrategy, combined with the characteristics of Z-source inverter, its comprehensive PCHmodel is established. On the basis of the PCH model by damping injection andinterconnection matrix design method, the Z-source energy-shaping control model isdesigned. The validity of the controller is validated by computer simulation. Based onthe above research, by comparing the PI control and energy-shaping control of theZ-source inverter, the merits and demerits of the two control methods are obtained. ThePI control has the disadvantages of parameters adjusting consuming time, poorrobustness, and often appearing output saturation or volatile situation. However, theenergy-shaping control has the advantages that the parameters can be calculated and therobustness is better.Finally, through the establishment of photovoltaic generation simulation model, theoutput characteristics and the MPPT control strategy are analyzed. On this basis,combining with the energy shaping control, the MPPT control algorithm is embeddedinto the energy-shaping controller in the form of differential equation. Then thecomprehensive control model of energy-shaping control for Z-source inverter in photovoltage power generation with MPPT is created. The overall system simulationresults prove the effectiveness of the control.