Research And Design Of Grid-Connected Three-Phase PV Inverter Based On The SVPWM

With the development of society, energy shortage and environment pollution is becoming more and more serious. Therefore, developing green non-pollution new energy has become the hot spot of the energy research. Solar , which is one of the endless green energy, has been vigorously adored. Photovoltaic (PV) grid generation technology is the main form of the solar energy application in the future.Through in-depth study on the principle of photovoltaic (PV) grid generation technology, the paper finally confirmed the SVPWM modulation technology as the foundation. Composite control method, which is based on PI control and repeat control, voltage feed-forward control, transforms and controls the output current of the inverter. As a result, the system could output the current which has the same phase and frequency. Furthermore, the output current waveform is perfect of which harmonic content is less. This paper mainly includes the following five aspects:1. Introduce the composition of the Photovoltaic power generation system, Analyses core components of the Photovoltaic power generation system , Grid inverter requirements, working principle and the topological structure, Choose a suitable three-phase bridge inverter.2. Analysis three topology structure of three-phase voltage source type grid inverter and control strategy, Namely L type, LC type, LCL type, respectively establish state space model for three-phase photovoltaic inverter using three different grid filter . Also the grid control strategy are further classified and analysis at the same time ,Choose a better performance filter of LCL topology structure as this type of research object.3. In-depth analysis of two kinds of modulation method of the grid inverter, Namely SPWM modulation technology and SVPWM modulation technology , Choose SVPWM control technology which has a good performance as this paper grid inverter modulation method.4. In order to improve the quality of grid current, put forward the hybrid control strategy combining based on vector transform, current PI control, repetitive control, voltage feed-forward control , Using the strategy to grid inverter greatly improved grid current quality, improve the system stability and anti-jamming ability. 5. Based on the above analysis, the paper has designed the 10 kW photovoltaic (PV) grid inverter simulation model. The paper has built simulation models of three control strategy for three-phase photovoltaic (PV) grid inverter based on SVPWM modulation technology in Matlab/Simulink. According to the simulation results, it can be seen that composite control strategy based on PI, repetitive control and voltage feed-forward control could improve the quality of the grid current. And the power factor of the inverter output power could reach to 1.