Research on the SVPWM Grid-connected System with Double Closed-loop Control Based on NPC Three-level Inverter

NPC three-level inverter is a new type of inverter topology. In order to improve the stability and power quality of two-level inverters when connected to the grid, an NPC three-level inverter and SVPWM dual closed-loop control strategy were designed on the basis of traditional two-level inverters. Design the inductance, resonant frequency and other parameters of the LCL filter, construct a relevant model, and use its output voltage and current values as inputs. The control signal of the NPC inverter is generated through a dual closed-loop control module and an SVPWM modulation module. Finally, by building a MATLAB/Simulink simulation model, comparative experiments were conducted with traditional two-level inverter circuits. The simulation results show that the proposed method can effectively improve the response speed, power quality and other properties of the system, and can effectively suppress system fluctuations in the face of interference, further improving the stability of the grid connected system.