Study On Parallel Inversion Technologies Based On Novel Composite Control Strategies

Inverter power supplies have many advantages,such as high reliability,safe operation,high power density and stable frequency amplitude,so they are widely used in many industrial fields.At present,the design of inverter power supply has been perfected,but there is still a disadvantage of a power supply output waveform difference and a weak load capacity.Therefore,how to use the corresponding control strategy to improve the output quality of the inverter power supply is a key problem that needs to be solved urgently.Study on Parallel Inversion technologies based on novel composite control strategies has important theoretical significance and practical value.Firstly,the mathematical model and topology of the three-phase combined inverter power supply are analyzed,and the factors that generate higher harmonics and the reasons that affect the quality of the output voltage waveform are listed.In order to cope with the nonlinear load,this set of inverters is combined.Based on the characteristics of the power supply,a suitable control algorithm is selected,and a new adaptive combined repetitive control strategy is proposed to improve the quality of the output side voltage waveform.Based on the three-phase combined power supply,the parallel system is studied.It adopts the control method without interconnection.The accuracy of the pre-synchronization before parallel is improved by using the SOGI control algorithm.The power calculation of active and reactive power is performed.The droop control lays the foundation and optimizes the drooping algorithm.A suppression inductor is added between the two inverters to enhance the function of the droop control in the power system.According to the optimized strategy and experimental adjustment,the appropriate one is selected.The droop coefficient is used to analyze the performance of the parallel system.The inverter power supply system during the island operation was simulated.The new composite control algorithm was used as the core to carry out detailedcomparative analysis on the various load conditions of the power supply.The parallel system is simulated and verified,and the adjustment ability of the drooping algorithm and the reliability of the switching time are verified.The overall design and analysis of the three-phase combined inverter power system is carried out,including transformer selection,passive output filter selection,device selection,drive selection;hardware circuit design includes: AC/DC voltage sampling circuit design,current sampling circuit design,hardware over current protection current design;main program writing,and interrupt service function writing.Finally,using STM32F407ZGT6 as the main control chip,a prototype of three-phase combined inverter power supply was built.Through the prototype experiment,the new composite control strategy of the inverter power supply was verified,and the working capacity of the inverter power supply during the island operation was analyzed.And reliability.