| With fossil fuels as the representative of the primary energy depleting anddemand for energy of human society increasing, the energy crisis has become a globalproblem. At the same time, the environmental pollution problems which caused byconsumption of traditional energy has caused more and more people’s attention.Therefore, the new energy humans want to develop need to have abundant andpollution-free characteristics. Solar energy as widely distributed green energy to meetthese two requirements.PV is the main form of solar energy utilization in the future. The inverter is thecore component of the photovoltaic system, solar system responsible for convertingsolar energy into electrical energy. Traditional three-level inverter belong to buckconverter, the output power has low voltage change rate and less harmonic contentand so on. But in order to prevent the short circuit state, the same bridge arm can’t beconducted at the same time so the phase modulated wave must contains dead time,which in turn reduces the system reliability and the quality of the output power. Forthe Z-source inverter that include Z-source network, can work in two modes ofstraight and non-straight state, and D can be adjusted to control the buckcharacteristics. Thus, Z-source inverter has a wider input voltage range and highersystem reliability. In order to give full play to the advantages of both, the paper takesa Z-source three-level inverter, and analyzes its topology and working principle.Policy on the use of SPWM modulation strategy and focus on the principle of layeredcarrier generation method is analyzed and simulated. Using the three-loop controlstrategy and network strategies to improve the quality of the current network and theconversion efficiency of the systems, and design hardware control part of it.By Matlab/simulink simulation tools to build a simulation model, simulationresults reach the theoretical expected results， verify the correctness and feasibility ofthe system. |
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